Sample records for giant paleo landslides
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McMurtry, Gary M.; Herrero-Bervera, Emilio; Cremer, Maximilian D.; Smith, John R.; Resig, Johanna; Sherman, Clark; Torresan, Michael E.
1999-01-01
Previous work has found evidence for giant tsunami waves that impacted the coasts of Lanai, Molokai and other southern Hawaiian Islands, tentatively dated at 100 + and 200 + ka by U-series methods on uplifted coral clasts. Seafloor imaging and related work off Hawaii Island has suggested the Alika phase 2 debris avalanche as the source of the ~ 100 ka "giant wave deposits", although its precise age has been elusive. More recently, a basaltic sand bed in ODP site 842 (~ 300 km west of Hawaii) estimated at 100 ?? 20 ka has been suggested to correlate with this or another large Hawaiian landslide. Our approach to the timing and linkage of giant submarine landslides and paleo-tsunami deposits is a detailed stratigraphic survey of pelagic deposits proximal to the landslide feature, beginning with a suite of seven piston, gravity and box cores collected in the vicinity of the Alika 2 slide. We used U-series dating techniques, including excess 230Th and 210Pb profiling, high-resolution paleomagnetic stratigraphy, including continuous, U-channel analysis, δ18O stratigraphy, visual and X-ray sediment lithology, and the petrology and geochemistry of the included turbidites and ash layers. Minimum ages for the Alika phase 2a slide from detailed investigation of two of the cores are 112 ± 15 ka and 125 ± 24 ka (2σ) based on excess 230Th dating. A less precise age for the Alika phase 1 and/or South Kona slide is 242 ± 80 ka (2σ), consistent with previous geological estimates. Oxygen isotope analyses of entrained planktonic foraminifera better constrain the Alika phase 2a maximum age at 127 ± 5 ka, which corresponds to the beginning of the stage 5e interglacial period. It is proposed that triggering of these giant landslides may be related to climate change when wetter periods increase the possibility of groundwater intrusion and consequent phreatomagmatic eruptions of shallow magma chambers. Our study indicates the contemporaneity of the Alika giant submarine landslides
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Directory of Open Access Journals (Sweden)
Panpan Tang
2015-07-01
Full Text Available The region near Dujiangyan City and Wenchuan County, Sichuan China, including significant giant panda habitats, was severely impacted by the Wenchuan earthquake. Large-area landslides occurred and seriously threatened the lives of people and giant pandas. In this paper, we report the development of an enhanced multi-temporal interferometric synthetic aperture radar (MTInSAR methodology to monitor potential post-seismic landslides by analyzing coherent scatterers (CS and distributed scatterers (DS points extracted from multi-temporal l-band ALOS/PALSAR data in an integrated manner. Through the integration of phase optimization and mitigation of the orbit and topography-related phase errors, surface deformations in the study area were derived: the rates in the line of sight (LOS direction ranged from −7 to 1.5 cm/a. Dozens of potential landslides, distributed mainly along the Minjiang River, Longmenshan Fault, and in other the high-altitude areas were detected. These findings matched the distribution of previous landslides. InSAR-derived results demonstrated that some previous landslides were still active; many unstable slopes have developed, and there are significant probabilities of future massive failures. The impact of landslides on the giant panda habitat, however ranged from low to moderate, would continue to be a concern for conservationists for some time in the future.
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A preliminary study of landslide gouge dating by TL technique
Energy Technology Data Exchange (ETDEWEB)
Fengju, Ji; Jianping, Li [Inst. of Geology, National Seismological Bereau, Beijing (China); Mingda, Liu [Inst. of Crustal Dynamics, SSB, Beijing (China)
1993-04-01
The key to date slipping of landslide by TL method is whether the temperature and pressure caused by slipping can lead the original TL to 'zero'for some minerals within the slipping band. For this purpose, the simulated experiments under different temperature-pressure were made and the TL annealing effect of landslide gouge was studied. The results show that the frictional heating caused during slipping is a main factor leading the mineral's TL to decrease on the slip plane and that increment of temperature is in close relation with strength of shear stress, thickness of landslide gouge and amount of displacement. As an example, the slipping age of a paleo-landslide at Huangtupo, Hubei Province, has been dated to be about 140 ka.
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Kaucká, Petra
2012-01-01
Topic: Paleo Diet Objectives: The aim of bachelor thesis is to study available literature about Paleo Diet and evaluated it. Then determine whether there is awareness of Paleo Diet in Czech republic. In addition, find out whether there is any experience in dieting according to Paleo Diet and whether Paleo Diet coul be applied in our environment. Methods: As a source of information served a survey. The research group consists of respondents who should have any experience in dieting according t...
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Giant landslides and turbidity currents in the Agadir Canyon Region, NW-Africa
Krastel, Sebastian; Wynn, Russell B.; Stevenson, Christopher; Feldens, Peter; Mehringer, Lisa; Schürer, Anke
2017-04-01
Coring and drilling of the Moroccan Turbidite System off NW-Africa revealed a long sequence of turbidites, mostly sourced from the Moroccan continental margin and the volcanic Canary Islands. The largest individual flow deposits in the Moroccan Turbidite System contain sediment volumes >100 km3, although these large-scale events are relatively infrequent with a recurrence interval of 10,000 years (over the last 200,000 years). The largest siliciclastic flow in the last 200,000 years was the 'Bed 5 event', which transported 160 km3 of sediment up to 2000 km from the Agadir Canyon region to the southwest Madeira Abyssal Plain. While the Moroccan Turbidite System is extremely well investigated, almost no data from the source region, i.e. the Agadir Canyon, are available. Understanding why some submarine landslides remain as coherent blocks of sediment throughout their passage downslope, while others mix and disintegrate almost immediately after initial failure, is a major scientific challenge, which was addressed in the Agadir Canyon source region during RV Maria S. Merian Cruise MSM32 in late 2013. A major landslide area was identified 200 km south of the Agadir Canyon. A landslide was traced from this failure area to the Agadir Canyon. This landslide entered the canyon in about 2500 m water depth. Despite a significant increase in slope angle, the landslide did not disintegrate into a turbidity current when entering the canyon but moved on as landslide for at least another 200 km down the canyon. The age of the landslide ( 145 ka) does not correspond to any major turbidte deposit in the Moroccan Turbidite System, further supporting the fact that the landslide did not disintegrate into a major turbidity current. A core taken about 350 m above the thalweg in the head region of Agadir Canyon shows a single coarse-grained turbidite, which resembles the composition of the Bed 5 event in the Madeira Abyssal Plain. Hence, the Bed 5 turbidite originated as a failure in the
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Submarine landslides on the north continental slope of the South China Sea
Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping
2018-02-01
Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.
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Krastel, Sebastian; Böttner, Christof; Cartigny, Matthieu; Feldens, Peter; Fu, Lili; Glogowski, Silke; Guggolz, Theresa; Hellmann, Sebastian; Hühnerbach, Veit; Jähmlich, Heiko; Kraus, Katrin; Kretschmer, Jacob; Matthew, Duncan; Meier, Daniela; Mücke, Isabell
2014-01-01
Agadir Canyon is one of the largest submarine canyons in the World, supplying giant submarine sediment gravity flows to the Agadir Basin and the wider Moroccan Turbidite System. While the Moroccan Turbidite System is extremely well investigated, almost no data from the source region, i.e. the Agadir Canyon, are available. Understanding why some submarine landslides remain as coherent blocks of sediment throughout their passage downslope, while others mix and disintegrate almost immediately af...
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Wang, H. B.; Li, J. W.; Zhou, B.; Yuan, Z. Q.; Chen, Y. P.
2013-03-01
In the last few decades, the development of Geographical Information Systems (GIS) technology has provided a method for the evaluation of landslide susceptibility and hazard. Slope units were found to be appropriate for the fundamental morphological elements in landslide susceptibility evaluation. Following the DEM construction in a loess area susceptible to landslides, the direct-reverse DEM technology was employed to generate 216 slope units in the studied area. After a detailed investigation, the landslide inventory was mapped in which 39 landslides, including paleo-landslides, old landslides and recent landslides, were present. Of the 216 slope units, 123 involved landslides. To analyze the mechanism of these landslides, six environmental factors were selected to evaluate landslide occurrence: slope angle, aspect, the height and shape of the slope, distance to river and human activities. These factors were extracted in terms of the slope unit within the ArcGIS software. The spatial analysis demonstrates that most of the landslides are located on convex slopes at an elevation of 100-150 m with slope angles from 135°-225° and 40°-60°. Landslide occurrence was then checked according to these environmental factors using an artificial neural network with back propagation, optimized by genetic algorithms. A dataset of 120 slope units was chosen for training the neural network model, i.e., 80 units with landslide presence and 40 units without landslide presence. The parameters of genetic algorithms and neural networks were then set: population size of 100, crossover probability of 0.65, mutation probability of 0.01, momentum factor of 0.60, learning rate of 0.7, max learning number of 10 000, and target error of 0.000001. After training on the datasets, the susceptibility of landslides was mapped for the land-use plan and hazard mitigation. Comparing the susceptibility map with landslide inventory, it was noted that the prediction accuracy of landslide occurrence
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Swann, Zerathe; Laurence, Audin; Carlos, Benavente; Régis, Braucher; Pierre-Henri, Blard; Didier, Bourlès; Julien, Carcaillet; Fabrizio, Delgado; Pascal, Lacroix; Valderrama Patricio, Murillo; Aster Team
2015-04-01
Giant landslides are recognized to be remarkably abundant on the Western Andean front of southern Peru and northern Chile, especially in the Arica Bend region (e.g. Crosta et al., 2014a). This area is characterized by strong topographic gradients and subsequent incision of deep canyons, due to the evolution of the Andean range that provide suitable conditions for the development of such instabilities. The climate is hyper-arid (Atacama Desert), although rare but highly impulsive wet events have been evidenced since the Pleistocene. In parallel, this region is submitted to strong (Mw 8-9) and recurrent (~100 yrs) subduction earthquakes. Previous studies suggest that large landslides represent the main agent of erosion of the Western Cordillera, providing soft material for subsequent fluvial remobilization. However the lack of time constrains on the numerous fossil landslides identified away from major canyons still hamper to assess a real mass balance of sliding material versus the known fluvial erosion and tectonic uplift rates. Finally the role of landslides in the long-term erosion rates of the Andean range on its arid flank remains quantitatively unknown. Recently, two studies gave divergent opinions about the main factor supposed to control the slope failures in that region. Based on cosmogenic nuclides derived erosion rates, McPhillips et al. (2014) argue that the last Holocene climate variation did not have had any effect on the rate of landsliding, suggesting that here landslides are mainly triggered by earthquake. On the other hand, Margirier et al. (2014) have showed a temporal correlation between a failure episode of the giant Chuquibamba landslide and the Ouki wet climatic event identified on the Altiplano ~100 ka ago. In this study we focus on dating the Cerro Caquilluco rock avalanche complex described by Crosta et al. (2014). With a total volume of about 15 km3, a length of 43 km and an internal structure characterized by various depositional lobes
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Silicon and Ge in the deep sea deduced from Si isotope and Ge measurements in giant glass sponges
Jochum, K. P.; Schuessler, J. A.; Haug, G. H.; Andreae, M. O.; Froelich, P. N.
2016-12-01
Biogenic silica, such as giant glass spicules of the deep-sea sponge Monorhaphis chuni, is an archive to monitor paleo-Si and -Ge in past seawater. Here we report on Si isotopes and Ge/Si ratios in up to 2.7 m long spicules using LA-(MC)-ICP-MS. Isotope ratios of Si are suitable proxies for Si concentrations in seawater, because Si isotope fractionation into biogenic silica is a function of seawater dissolved Si concentration. The δ30Si values for our specimens range from about - 0.5 ‰ to - 3.6 ‰ and are much lower than modern (>1000 m) seawater δ30Si of about 1.3 ‰. Interestingly, there is a systematic Si isotopic and Ge variation from the rim to the center of the cross sections, which we interpret as seawater paleo-Si and -Ge changes. The lifetime of the giant sponges appears to be between about 6 and 14 ka. These age estimates were obtained by comparing our analytical data with various paleo-markers of the glacial-interglacial termination. Thus, the entire Holocene and the end of the last glacial period are contained in the oldest giant spicules. The derived Si and Ge seawater concentrations are ca. 12 % higher and 20 % lower, respectively, during the late glacial than at present. Possible explanations for changing Si, Ge and Ge/Si during the deglaciation could be changes in riverine, glacial, and/or eolian deliveries of silica to the oceans and changes in marine sedimentary reverse weathering, which removes Ge into marine sediments during opal dissolution and diagenesis.
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Urban Landslides Induced by the 2004 Niigata-Chuetsu Earthquake
Kamai, T.; Trandafir, A. C.; Sidle, R. C.
2005-05-01
Landslides triggered by the Chuetsu earthquake occurred in artificial slopes of some new developments in suburban Nagaoka, the largest city in the affected area. The landslides occurred in hilly terrain of the eastern part of Nagaoka between the alluvial plain and Tertiary folded mountains of Yamakoshi. Although the extent of landslides in urban Nagaoka was small compared with landslides on natural slopes (especially near Yamakoshi), they represent an important case study for urban landslide disasters. Slope instabilities in urban residential areas were classified as: A) landslides in steep embankments; B) landslides in gently sloping artificial valley fills; C) re-activation of old landslides; and D) liquefaction in deep artificial valley fills. All these failures occurred in relatively uniform suburban landscapes, which were significantly modified from the original landforms. Recent destructive earthquakes in Japan caused similar types of slope failures in urban regions, suggesting that lessons from past earthquakes were not implemented. The greatest damage due to type-A failures occurred in the 25-yr old Takamachi residential area, where about 70 of 522 homes were judged to be uninhabitable. Before development, this area was an isolated hill (90 m elevation) with an adjacent terrace (60 m elevation) consisting of gravel, sand, and silt of the lower to middle Pleistocene deposits. Development earthworks removed the hill crest and created a wide plateau (70 m elevation); excavated soil was placed on the perimeter as an embankment. During the earthquake, the embankment slope collapsed, including retaining walls, perimeter road, and homes. The most serious damage occurred in five places around the margin of the plateau corresponding to shallow valley fills (5 to 8 m thick). Earthquake response analyses using an equivalent linear model indicated the amplification of seismic waves at the surface of embankment slopes, and the peak earthquake acceleration exceeded 1 G
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Vertebrate Fossils Imply Paleo-elevations of the Tibetan Plateau
Deng, T.; Wang, X.; Li, Q.; Wu, F.; Wang, S.; Hou, S.
2017-12-01
The uplift of the Tibetan Plateau remains unclear, and its paleo-elevation reconstructions are crucial to interpret the geodynamic evolution and to understand the climatic changes in Asia. Uplift histories of the Tibetan Plateau based on different proxies differ considerably, and two viewpoints are pointedly opposing on the paleo-elevation estimations of the Tibetan Plateau. One viewpoint is that the Tibetan Plateau did not strongly uplift to reach its modern elevation until the Late Miocene, but another one, mainly based on stable isotopes, argues that the Tibetan Plateau formed early during the Indo-Asian collision and reached its modern elevation in the Paleogene or by the Middle Miocene. In 1839, Hugh Falconer firstly reported some rhinocerotid fossils collected from the Zanda Basin in Tibet, China and indicated that the Himalayas have uplifted by more than 2,000 m since several million years ago. In recent years, the vertebrate fossils discovered from the Tibetan Plateau and its surrounding areas implied a high plateau since the late Early Miocene. During the Oligocene, giant rhinos lived in northwestern China to the north of the Tibetan Plateau, while they were also distributed in the Indo-Pakistan subcontinent to the south of this plateau, which indicates that the elevation of the Tibetan Plateau was not too high to prevent exchanges of large mammals; giant rhinos, the rhinocerotid Aprotodon, and chalicotheres still dispersed north and south of "Tibetan Plateau". A tropical-subtropical lowland fish fauna was also present in the central part of this plateau during the Late Oligocene, in which Eoanabas thibetana was inferred to be closely related to extant climbing perches from South Asia and Sub-Saharan Africa. In contrast, during the Middle Miocene, the shovel-tusked elephant Platybelodon was found from many localities north of the Tibetan Plateau, while its trace was absent in the Siwaliks of the subcontinent, which implies that the Tibetan Plateau had
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Elashvili, M.; Javakhishvili, Z.; Godoladze, T.; Karakhanyan, A.; Sukhishvili, L.; Nikolaeva, E.; Sokhadze, G.; Avanesyan, M.
2012-12-01
Current study concerns Javakheti area in the Lesser Caucasus. This area comprises a volcanic plateau with more than 20 volcanoes, several of them dated as having erupted during the Holocene. In the region the upper part of Lava complex is represented by Middle-Upper Quaternary formations. The region is an area of young deformations in the Alpine belt. Formation of relief began at the neotectonic stage (Sarmatian) and continues at present. Javakheti is one of the most seismically active regions in the Caucasus, earthquakes of 1899 and 1986 with magnitudes up to 6.0, causing severe damage and hundreds of casualties, occurred there. Historical data on earthquakes in 1088 and 1899 locate them in the same region, highlighting the importance on learning about the location and characteristics of their seismic sources. Javakheti highland seems to be actively populated at least from the Bronze Age period, forming a local culture to be strongly affected by Natural catastrophes and significant changes in Landscapes and climate. Study of potential seismic and associated natural hazards, such as landslide and rockfalls, possible volcanic activity in the region, including paleo and historical evidences, were addressed by number of International Projects (ISTC A-1418, NATO SFP # 983284 ) and multidisciplinary studies carried out by the Institute of Earth Sciences. Data gathered after the Installation of local GPS and Seismic networks have provided new look on seismicity pattern of the region and major seismic sources, while field studies (Geophysical survey, Paleo trenching, Archaeological studies, etc.) have provided new information on the dramatic Natural disasters which occurred in the region and probably played a vital role in its history. Remote sensing techniques became widely used in geological investigations during the decades. Interferometric synthetic aperture radar (InSAR), aerial and optical data analysis have contributed to the development of this work.. Case studies
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Luiza Coelho Netto, Ana; Facadio, Ana Carolina; Pereira, Roberta; Lima, Pedro Henrique
2017-04-01
Paleo-environmental studies point out an alternation of wet and dry periods during the Holocene in southeastern Brazil, marked by the expansion and retraction of the humid tropical rainforest in alternation with the campos de altitude vegetation ('high altitude grassland'); successive episodes of natural fire were recorded from 10,000 to 4,000 years BP in the mountainous region of SE-Brazil, reflecting warm-dry conditions. Present seasonal climatic variability is indicated by an increasing dry spell frequency throughout the XX and early XXI centuries together with an increasing rainfall concentration in the summer when extreme daily totals (above 100 mm) become progressively more frequent. Historical land use changes, at both regional and local scales, are mostly related to this climatic variability. Therefore extreme rainfall induced landslides have been responsible for severe disasters as recorded along the Atlantic slopes of Serra do Mar. The extreme one occurred in January 2011, affecting the municipalities of Nova Friburgo, Teresópolis and Petrópolis. Studies in Nova Friburgo shown the occurrence of 3.622 landslides scars within an area of 421 km2; this rainfall event reached the expected average monthly rainfall (300 mm) in less than 10 hours. The D'Antas creek basin (53 km2) was the most affected area by landslides; 86% of 326 scars where associated with shallow translational mechanisms among which 67% occurred within shallow concave up topographic hollows of 32° slope angle in average. Most of these landslide scars occurred in granite rocks and degraded vegetation due to historical land use changes (last 200 years) including secondary forest (64%) and grasslands (25%). The present-day association between extreme rainfall induced landslides and human induced vegetation changes seem to reflect similar geomorphic responses to natural Holocene bioclimatic changes; a common phenomenon between the two periods is fire (natural fire in the past time and man
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Gariano, Stefano Luigi; Guzzetti, Fausto
2017-04-01
According to the fifth report of the Intergovernmental Panel on Climate Change, "warming of the climate system is unequivocal". The influence of climate changes on slope stability and landslides is also undisputable. Nevertheless, the quantitative evaluation of the impact of global warming, and the related changes in climate, on landslides remains a complex question to be solved. The evidence that climate and landslides act at only partially overlapping spatial and temporal scales complicates the evaluation. Different research fields, including e.g., climatology, physics, hydrology, geology, hydrogeology, geotechnics, soil science, environmental science, and social science, must be considered. Climatic, environmental, demographic, and economic changes are strictly correlated, with complex feedbacks, to landslide occurrence and variation. Thus, a holistic, multidisciplinary approach is necessary. We reviewed the literature on landslide-climate studies, and found a bias in their geographical distribution, with several studies centered in Europe and North America, and large parts of the world not investigated. We examined advantages and drawbacks of the approaches adopted to evaluate the effects of climate variations on landslides, including prospective modelling and retrospective methods that use landslide and climate records, and paleo-environmental information. We found that the results of landslide-climate studies depend more on the emission scenarios, the global circulation models, the regional climate models, and the methods to downscale the climate variables, than on the description of the variables controlling slope processes. Using ensembles of projections based on a range of emissions scenarios would reduce (or at least quantify) the uncertainties in the obtained results. We performed a preliminary global assessment of the future landslide impact, presenting a global distribution of the projected impact of climate change on landslide activity and abundance
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Landslide prediction system for rainfall induced landslides in Slovenia (Masprem
Directory of Open Access Journals (Sweden)
Mateja Jemec Auflič
2016-12-01
Full Text Available In this paper we introduce a landslide prediction system for modelling the probabilities of landslides through time in Slovenia (Masprem. The system to forecast rainfall induced landslides is based on the landslide susceptibility map, landslide triggering rainfall threshold values and the precipitation forecasting model. Through the integrated parameters a detailed framework of the system, from conceptual to operational phases, is shown. Using fuzzy logic the landslide prediction is calculated. Potential landslide areas are forecasted on a national scale (1: 250,000 and on a local scale (1: 25,000 for fie selected municipalities where the exposure of inhabitants, buildings and different type of infrastructure is displayed, twice daily. Due to different rainfall patterns that govern landslide occurrences, the system for landslide prediction considers two different rainfall scenarios (M1 and M2. The landslides predicted by the two models are compared with a landslide inventory to validate the outputs. In this study we highlight the rainfall event that lasted from the 9th to the 14th of September 2014 when abundant precipitation triggered over 800 slope failures around Slovenia and caused large material damage. Results show that antecedent rainfall plays an important role, according to the comparisons of the model (M1 where antecedent rainfall is not considered. Although in general the landslides areas are over-predicted and largely do not correspond to the landslide inventory, the overall performance indicates that the system is able to capture the crucial factors in determining the landslide location. Additional calibration of input parameters and the landslide inventory as well as improved spatially distributed rainfall forecast data can further enhance the model's prediction.
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Assessing landslide exposure in areas with limited landslide information
Pellicani, R.; van Westen, C.J.; Spilotro, G.
2014-01-01
Landslide risk assessment is often a difficult task due to the lack of temporal data on landslides and triggering events (frequency), run-out distance, landslide magnitude and vulnerability. The probability of occurrence of landslides is often very difficult to predict, as well as the expected
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Environmental impact of the landslides caused by the 12 May 2008, Wenchuan, China earthquake
Highland, Lynn; Sun, Ping; Edited by Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji
2013-01-01
The magnitude 7.9 (Mw) Wenchuan, China, earthquake of May 12, 2008 caused at least 88,000 deaths of which one third are estimated to be due to the more than 56,000 earthquake-induced landslides. The affected area is mountainous, featuring densely-vegetated, steep slopes through which narrowly confined rivers and streams flow. Numerous types of landslides occurred in the area, including rock avalanches, rock falls, translational and rotational slides, lateral spreads and debris flows. Some landslides mobilized hundreds of million cubic meters of material, often resulting in the damming of rivers and streams, impacting river ecosystems and morphology. Through an extensive search of both Chinese- and English-language publications we provide a summary of pertinent research on environmental effects, emphasizing key findings. Environmental effects caused by landslides include the alteration of agriculture, changes to natural ecosystems, changes in river morphology due to landslide dams and other effects such as sedimentation and flooding. Damage by landslides to the giant panda reserve infrastructure and habitat, was severe, threatening the survival of one of the world’s rarest species. The Panda reserves are of national significance to China, and to the vital tourism economy of the region. One of the major impacts to both the natural and built environment is the complete relocation of some human populations and infrastructure to new areas, resulting in the abandonment of towns and other areas that were damaged by the earthquake and landslides. The landslide effects have affected the biodiversity of the affected area, and it has been hypothesized that strict forest preservation measures taken in the years preceding the earthquake resulted in a reduction of the environmental damage to the area.
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Allen, R. L.
2016-12-01
Computer enhancing of side scanning sonar plots revealed images of massive art, apparent ruins of cities, and subsea temples. Some images are about four to twenty kilometers in length. Present water depths imply that many of the finds must have been created over ten thousand years ago. Also, large carvings of giant sloths, Ice Age elk, mammoths, mastodons, and other cold climate creatures concurrently indicate great age. In offshore areas of North America, some human faces have beards and what appear to be Caucasian characteristics that clearly contrast with the native tribal images. A few images have possible physical appearances associated with Polynesians. Contacts and at least limited migrations must have occurred much further in the ancient past than previously believed. Greatly rising sea levels and radical changes away from late Ice Age climates had to be devastating to very ancient civilizations. Many images indicate that these cultures were capable of construction and massive art at or near the technological level of the Old Kingdom in Egypt. Paleo astronomy is obvious in some plots. Major concerns are how to further evaluate, catalog, protect, and conserve the creations of those cultures.
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Damm, Bodo; Klose, Martin
2014-05-01
This contribution presents an initiative to develop a national landslide database for the Federal Republic of Germany. It highlights structure and contents of the landslide database and outlines its major data sources and the strategy of information retrieval. Furthermore, the contribution exemplifies the database potentials in applied landslide impact research, including statistics of landslide damage, repair, and mitigation. The landslide database offers due to systematic regional data compilation a differentiated data pool of more than 5,000 data sets and over 13,000 single data files. It dates back to 1137 AD and covers landslide sites throughout Germany. In seven main data blocks, the landslide database stores besides information on landslide types, dimensions, and processes, additional data on soil and bedrock properties, geomorphometry, and climatic or other major triggering events. A peculiarity of this landslide database is its storage of data sets on land use effects, damage impacts, hazard mitigation, and landslide costs. Compilation of landslide data is based on a two-tier strategy of data collection. The first step of information retrieval includes systematic web content mining and exploration of online archives of emergency agencies, fire and police departments, and news organizations. Using web and RSS feeds and soon also a focused web crawler, this enables effective nationwide data collection for recent landslides. On the basis of this information, in-depth data mining is performed to deepen and diversify the data pool in key landslide areas. This enables to gather detailed landslide information from, amongst others, agency records, geotechnical reports, climate statistics, maps, and satellite imagery. Landslide data is extracted from these information sources using a mix of methods, including statistical techniques, imagery analysis, and qualitative text interpretation. The landslide database is currently migrated to a spatial database system
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Vogel, Sebastian; Märker, Michael
2010-05-01
SSP1.4 Understanding mixed siliciclastic-volcaniclastic depositional systems and their relationships with geodynamics or GD2.3/CL4.14/GM5.8/MPRG22/SSP3.5 Reconstruction of ancient continents: Dating and characterization of paleosurfaces Reconstructing the paleo-topography and paleo-environmental features of the Sarno River plain (Italy) before the AD 79 eruption of Somma-Vesuvius volcanic complex Sebastian Vogel[1] & Michael Märker[1] [1] Heidelberg Academy of Sciences and Humanities c/o University of Tübingen, Rümelinstraße 19-23, D-72070 Tübingen, Germany. Within the geoarchaeological research project "Reconstruction of the Ancient Cultural Landscape of the Sarno River Plain" undertaken by the German Archaeological Institute in cooperation with the Heidelberg Academy of Sciences and Humanities/University of Tübingen a methodology was developed to model the spatial dispersion of volcanic deposits of Somma-Vesuvius volcanic complex since its Plinian eruption AD 79. Eventually, this was done to reconstruct the paleo-topography and paleo-environment of the Sarno River plain before the eruption AD 79. We collected, localized and digitized more than 1,800 core drillings to gain a representative network of stratigraphical information covering the entire plain. Besides other stratigraphical data including the characteristics of the pre-AD 79 stratum, the depth to the pre-AD 79 paleo-surface was identified from the available drilling documentation. Instead of applying a simple interpolation of the drilling data, we reconstructed the pre-AD 79 paleo-surface with a sophisticated geostatistical methodology using a machine based learning approach based on classification and regression trees. We hypothesize that the present-day topography reflects the ancient topography, because the eruption of AD 79 coated the ancient topography, leaving ancient physiographic elements of the Sarno River plain still recognizable in the present-day topography. Therefore, a high resolution
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Multi-event behavior of El Golfo landslide (El Hierro Island, Canary Archipelago)
León, Ricardo; Biain, Ander; Urgeles, Roger; Somoza, Luis; Ferrer, Mercedes; García-Crespo, Jesús; Francisco Mediato, José; Galindo, Inés; Yepes, Jorge; Gimenez-Moreno, Julia
2017-04-01
Based on the re-interpretation of a vast onshore-offshore data set, a new morpho-structural characterization of the El Golfo giant landslide in the island of El Hierro (Canary Archipelago, Spain) is presented. Offshore multibeam echosounder data, chirp sub-bottom profiles, multichannel seismic reflection data and onshore information from water wells and galleries have been analyzed to determine the nature of the event. The subaerial headscarp shows a non-continuous arcuate profile formed by two nested semi-circular amphitheaters that extend offshore along a smooth chute, suggesting the occurrence of at least two large retrogressive events. Channels/gullies and escarpments developed along the submarine sector of the scar also indicate smaller-scale events and predominance of sediment bypass. At the base of submerged island, two subunits within the related submarine mass transport deposit (MTD) are identified on multichannel seismic reflection profiles confirming the multi-event nature of the landslide. The MTD, identified as a debris avalanche, has a total estimated volume of 318 km3: 84 km3 and 234 km3, for the lower and upper subunits respectively. Data from wells and galleries show abrasion platforms with beach deposits at sea-level (0 masl) formed after the landslide scar and buried by the El Golfo post-collapse infill lavas, suggesting an age at least older than 23.5-82.5 ka for the landslide. This work has been supported by the projects IGCP-640 S4SLIDE, High resolution seabed mapping EASME/EMFF/2016/005 and CTM2010-09496-E. Keywords: Submarine landslides, volcanic islands, debris avalanche, Canary Islands
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Modelling the landslide area and sediment discharge in landslide-dominated region, Taiwan
Teng, Tse-Yang; Huang, -Chuan, Jr.; Lee, Tsung-Yu; Chen, Yi-Chin; Jan, Ming-Young; Liu, Cheng-Chien
2016-04-01
Many studies have indicated the magnified increase of rainfall intensification, landsliding and subsequent sediment discharge due to the global warming effect. However, a few works synthesized the "chain reaction" from rainfall, landsliding to sediment discharge at the same time because of the limited observations of landslide area and sediment discharge during episodes. Besides, the sediment transport strongly depends on the sediment supply and stream power which interact conditionally. In this study, our goal is to build a model that can simulate time-series landslide area and subsequent sediment discharge. The synthesized model would be applied onto Tsengwen Reservoir watershed in southern Taiwan, where lots of landslides occur every year. Unlike other studies, our landslide model considers not only rainfall effect but also previous landslide status, which may be applied to landslide-dominated regions and explains the irrelevant relationship between typhoon rainfall and landslide area. Furthermore, our sediment transport model considers the sediment budget which couples transport- and supply-limited of sediment. The result shows that the simulated time-series landslide area and the sediment transport agree with the observation and the R2 are 0.88 and 0.56, respectively. Reactivated ratio of previous landslide area is 72.7% which indicates the high reoccurrence of historical landslide in landslide-dominated regions. We divided nine historical typhoons into three periods to demonstrate the effect of sediment supply/supply-limited condition upon sediment transport. For instance, the rainfall is smaller in period 3 than in period 1 but the sediment transport is higher in period 3 due to the catastrophic landslide (typhoon Morakot) during period 2. We argue that quantifying sediment transport should couple not only with water discharge but sediment budget, which is rarely considered in calculating sediment transport. Moreover, the parameterization of the controlling
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Experience in landslide control
Energy Technology Data Exchange (ETDEWEB)
Koz' min, L S
1983-06-01
The problems of slope stability in the Krasnoyarskugol' surface mines are discussed. Methods used for slide prevention and slide control from 1977 to 1982 are analyzed. Landslides were caused by weathering of the argillite layer in the coal seam roof. Sliding plane was parallel to the coal seam roof. At a later stage of landslide prevention sliding planes were in the coal seam floor (which consisted of weak rock layers). Range of landslides was evaluated. Losses caused by landslides were discussed: working time losses, losses of coal, damaged equipment. Landslide hazards were controlled by reducing slope angle and by changing cut geometry. Cross section of the cut with a spoil bank prone to landslides is shown in a scheme. Reducing angle of slope inclination, using strong rock layers as the spoil bank base and changing cut geometry eliminated landslides in 1982. Recommendations on landslide control in coal surface mines with layers of weak rocks influenced by weathering are made.
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Landslide hazard and risk assessment using semi-automatically created landslide inventories
Martinez, J.A.; van Westen, C.J.; Kerle, N.; Jetten, V.G.; Kumar, K.V.
2013-01-01
Landslide inventories prepared manually from remote sensing data or through field surveys have shown to be useful for preparation of landslide susceptibility and hazard maps. Recent literatures show several studies have been carried out to prepare landslide inventories from satellite data by
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How to make stone soup: Is the "Paleo diet" a missed opportunity for anthropologists?
Chang, Melanie L; Nowell, April
2016-09-01
For the past few years, people everywhere have been "going Paleo." Websites and social media touting the benefits of eating a "Paleo diet" and following a "Paleolithic life style" serve as calls to arms for health-conscious individuals seeking information about the latest health and fitness trends. Many of these people participate in programs such as Crossfit, which involve major social and life-style modification components and therefore facilitate the dissemination of dietary fads. 1 The PALEOf(x) TM conference, which bills itself as "the world's premier holistic wellness event," has attracted sellout crowds of thousands of attendees for the last four years. 2 Consumers can wear Paleo clothing, download Paleo shopping and exercise apps to their smartphones, order prepackaged Paleo food, prepare it using Paleo cooking implements, or expediently buy Paleo convenience foods from Paleodiet™ vending machines 3 and "Cultured Caveman" food trucks. 4 The Paleo diet is touted by movie stars, reality TV personalities, and professional athletes, including LeBron James and the entire Miami Dolphins NFL team. 5,6 Books with titles such as The Primal Blueprint, 7 Cavewomen Don't Get Fat, 8 and Paleo Perfected 9 (the latter by the stodgy America's Test Kitchen) are legion, and many are bestsellers. © 2016 Wiley Periodicals, Inc.
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Directory of Open Access Journals (Sweden)
Xin Wang
2010-09-01
Full Text Available As catastrophic phenomena, landslides often cause large-scale socio-economic destruction including loss of life, economic collapse, and human injury. In addition, landslides can impair the functioning of critical infrastructure and destroy cultural heritage and ecological systems. In order to build a more landslide resistant and resilient society, an original GIS-based decision support system is put forth in order to help emergency managers better prepare for and respond to landslide disasters. The GIS-based landslide monitoring and management system includes a Central Repository System (CRS, Disaster Data Processing Modules (DDPM, a Command and Control System (CCS and a Portal Management System (PMS. This architecture provides valuable insights into landslide early warning, landslide risk and vulnerability analyses, and critical infrastructure damage assessments. Finally, internet-based communications are used to support landslide disaster modelling, monitoring and management.
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International Nuclear Information System (INIS)
Kubik, Peter W.; Ivy-Ochs, Susan
2004-01-01
The sea level, high latitude 10 Be production rate for exposure dating obtained from the giant 9.8 ka landslide of Koefels (Austria) has been calculated based on a re-assessment of the contribution of the muonic cosmic ray component. The 0-10 ka production rate value is 5.44 ± 0.19 10 Be atoms/y g quartz
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Numerical modelling comparison of slow landslides: the Portalet case study (Central Pyrenees-Spain)
Fernandez-Merodo, Jose Antonio; Garcia-Davalillo, Juan Carlos; Herrera, Gerardo
2013-04-01
Slow-moving landslides are a wide-spread type of active mass movement that cause severe damages to infrastructures and may be a precursor of sudden catastrophic slope failures. In this context, modelling slow-moving landslide behaviour is an important task in order to quantify and reduce the risk associated to this geological process. In practice, landslide occurrence and stability conditions are evaluated for a given scenario through a stability factor based on limit equilibrium analysis. This "static" approximation is hardly applied when boundary conditions are time dependent. Apart from earthquake studies, time dependent analysis is required when: (i) hydrological conditions change as in the case of rainfall; (ii) resistant parameters are reduced as in the case of strain softening or weathering processes and (iii) creep behaviour is taken into account. Different numerical models can be applied to reproduce the kinematic behaviour of large slow landslides. This paper compares four different models: i) a direct correlation with measured rainfall, ii) a simple 1D infinite slope viscoplastic model [1], iii) a 2D elasto-plastic finite element model [2] and iv) a 2D visco-plastic finite element model [3]. These models, ordered by increasing level of complexity, are compared by applying them to the Portalet case study. The Portalet landslide (Central Spanish Pyrenees) is an active paleo-landslide that has been "reactivated" by the construction of a parking area at the toe of the slope in 2004. This landslide is still active despite the corrective measures carried out to stabilize it. The measurements obtained with different monitoring techniques (ground based SAR, advanced DInSAR processing of satellite SAR images, DGPS and inclinometers) indicate that the hillside is still moving today following two patterns. The first one corresponds to a slow continuous motion of constant speed of about 100 mm/year, the second one corresponds to accelerations of the moving mass when
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International Nuclear Information System (INIS)
Huang Shijie
1997-01-01
On the basis of comprehensively analyzing paleo-channel sandstone type uranium deposits at home and abroad, the author discusses the division of mineralization types of paleo-channel sandstone type uranium deposits, and analyzes the metallogenic geologic conditions such as regional geologic background, climatic and geomorphological conditions, basement and sedimentary cover, characteristics of paleo-valley and paleo-channel, mineralization features as well as epigenetic metallogenic process. Future prospecting direction is also proposed
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On the characteristics of landslide tsunamis.
Løvholt, F; Pedersen, G; Harbitz, C B; Glimsdal, S; Kim, J
2015-10-28
This review presents modelling techniques and processes that govern landslide tsunami generation, with emphasis on tsunamis induced by fully submerged landslides. The analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths. Scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed. It is found that the landslide acceleration determines the initial tsunami elevation for translational landslides, while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides. Retrogressive effects stretch the tsunami, and in certain cases produce enlarged amplitudes due to positive interference. In an example involving a deformable landslide, it is found that the landslide deformation has only a weak influence on tsunamigenesis. However, more research is needed to determine how landslide flow processes that involve strong deformation and long run-out determine tsunami generation. © 2015 The Authors.
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Small scale karst features (tube karren) as evidence of a latest Quaternary fossil landslide
Stöger, Tobias; Plan, Lukas; Draganits, Erich
2017-04-01
At least since 1933 numerous small dissolutional holes in the ceilings of overhangs and small caves have been known from a restricted area in the Northern Calcareous Alps in Lower Austria but not investigated yet. These tube-shaped structures are a few centimetres in diameter, more or less vertical, taper upwards, are closed at the top and penetrate some tens of centimetres into the Middle Triassic limestone. Very similar features were described by Simms (2002) from the shores of three lakes in western Ireland and termed Röhrenkarren or tube karren. According to his model they formed by condensation corrosion within air pockets trapped by seasonal floods. The features investigated in the present study occur on both sides of a valley in the north eastern part of the Northern Calcareous Alps south of the city Sankt Pölten. Presently there is no lake and so far no paleo lake is known from this area. Based on airborne laser scanning data and field observations in a narrow section of the valley downstream of the tube karren sites, a previously unknown potential fossil landslide was discovered. The clayey silty sediments upstream of the landslide are interpreted as palaeo-lake sediments. This interpretation is supported by the existence of abundant dragonfly eggs within these deposits. The same fine-grained sediments are partly also found inside the tube karren. These observations are interpreted that a landslide-dammed palaeo-lake formed due to the mass movement that blocked the river and the tube karren were formed by seasonal fluctuations of the lake level. Geochronological dating of calcite crusts covering the karren and of the organic material of the dragonfly eggs are on the way. As the karren features look quite fresh and unweathered and from the diffuse shape of the landslide a late Quaternary age is estimated. References Simms, M.J. 2002. The origin of enigmatic, tubular, lake-shore karren: a mechanism for rapid dissolution of limestone in carbonate
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Marc, Odin; Malet, Jean-Philippe; Stumpf, Andre; Gosset, Marielle
2017-04-01
In mountainous and hilly regions, landslides are an important source of damage and fatalities. Landsliding correlates with extreme rainfall events and may increase with climate change. Still, how precipitation drives landsliding at regional scales is poorly understood quantitatively in part because constraining simultaneously landsliding and rainfall across large areas is challenging. By combining optical images acquired from satellite observation platforms and rainfall measurements from satellite constellations we are building a database of landslide events caused by with single storm events. We present results from storm-induced landslides from Brazil, Taiwan, Micronesia, Central America, Europe and the USA. We present scaling laws between rainfall metrics derived by satellites (total rainfall, mean intensity, antecedent rainfall, ...) and statistical descriptors of landslide events (total area and volume, size distribution, mean runout, ...). Total rainfall seems to be the most important parameter driving non-linearly the increase in total landslide number, and area and volume. The maximum size of bedrock landslides correlates with the total number of landslides, and thus with total rainfall, within the limits of available topographic relief. In contrast, the power-law scaling exponent of the size distribution, controlling the relative abundance of small and large landslides, appears rather independent of the rainfall metrics (intensity, duration and total rainfall). These scaling laws seem to explain both the intra-storm pattern of landsliding, at the scale of satellite rainfall measurements ( 25kmx25km), and the different impacts observed for various storms. Where possible, we evaluate the limits of standard rainfall products (TRMM, GPM, GSMaP) by comparing them to in-situ data. Then we discuss how slope distribution and other geomorphic factors (lithology, soil presence,...) modulate these scaling laws. Such scaling laws at the basin scale and based only on a
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A landslide susceptibility map of Africa
Broeckx, Jente; Vanmaercke, Matthias; Duchateau, Rica; Poesen, Jean
2017-04-01
Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial patterns of landslides and rockfalls on this continent is very limited. Also in global landslide susceptibility maps, Africa is mostly underrepresented in the inventories used to construct these maps. As a result, predicted landslide susceptibilities remain subject to very large uncertainties. This research aims to produce a first continent-wide landslide susceptibility map for Africa, calibrated with a well-distributed landslide dataset. As a first step, we compiled all available landslide inventories for Africa. This data was supplemented by additional landslide mapping with Google Earth in underrepresented regions. This way, we compiled 60 landslide inventories from the literature (ca. 11000 landslides) and an additional 6500 landslides through mapping in Google Earth (including 1500 rockfalls). Various environmental variables such as slope, lithology, soil characteristics, land use, precipitation and seismic activity, were investigated for their significance in explaining the observed spatial patterns of landslides. To account for potential mapping biases in our dataset, we used Monte Carlo simulations that selected different subsets of mapped landslides, tested the significance of the considered environmental variables and evaluated the performance of the fitted multiple logistic regression model against another subset of mapped landslides. Based on these analyses, we constructed two landslide susceptibility maps for Africa: one for all landslide types and one excluding rockfalls. In both maps, topography, lithology and seismic activity were the most significant variables. The latter factor may be surprising, given the overall limited degree of seismicity in Africa. However, its significance indicates that frequent seismic events may serve as in important
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Analysis of Landslide Hazard Impact Using the Landslide Database for Germany
Klose, M.; Damm, B.
2014-12-01
The Federal Republic of Germany has long been among the few European countries that lack a national landslide database. Systematic collection and inventory of landslide data still shows a comprehensive research history in Germany, but only one focused on development of databases with local or regional coverage. This has changed in recent years with the launch of a database initiative aimed at closing the data gap existing at national level. The present contribution reports on this project that is based on a landslide database which evolved over the last 15 years to a database covering large parts of Germany. A strategy of systematic retrieval, extraction, and fusion of landslide data is at the heart of the methodology, providing the basis for a database with a broad potential of application. The database offers a data pool of more than 4,200 landslide data sets with over 13,000 single data files and dates back to 12th century. All types of landslides are covered by the database, which stores not only core attributes, but also various complementary data, including data on landslide causes, impacts, and mitigation. The current database migration to PostgreSQL/PostGIS is focused on unlocking the full scientific potential of the database, while enabling data sharing and knowledge transfer via a web GIS platform. In this contribution, the goals and the research strategy of the database project are highlighted at first, with a summary of best practices in database development providing perspective. Next, the focus is on key aspects of the methodology, which is followed by the results of different case studies in the German Central Uplands. The case study results exemplify database application in analysis of vulnerability to landslides, impact statistics, and hazard or cost modeling.
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A satellite-based global landslide model
Directory of Open Access Journals (Sweden)
A. Farahmand
2013-05-01
Full Text Available Landslides are devastating phenomena that cause huge damage around the world. This paper presents a quasi-global landslide model derived using satellite precipitation data, land-use land cover maps, and 250 m topography information. This suggested landslide model is based on the Support Vector Machines (SVM, a machine learning algorithm. The National Aeronautics and Space Administration (NASA Goddard Space Flight Center (GSFC landslide inventory data is used as observations and reference data. In all, 70% of the data are used for model development and training, whereas 30% are used for validation and verification. The results of 100 random subsamples of available landslide observations revealed that the suggested landslide model can predict historical landslides reliably. The average error of 100 iterations of landslide prediction is estimated to be approximately 7%, while approximately 2% false landslide events are observed.
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The National Landslide Information Center; data to reduce landslide damage
Brown, W. M.
1992-01-01
Almost every day a landslide disasters occurs somewhere in the world. Nearly any time there is heavy rainfall, an earthquake, a volcanic eruption, strong wave action on a shoreline, or some ill-considered alteration of sloping land by humans, landslides occur.
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Kirschbaum, Dalia; Malet, Jean-Philippe; Roessner, Sigrid
2017-04-01
Landslides occur around the world, on every continent, and play an important role in the evolution of landscapes. They also represent a serious hazard in many areas of the world. Despite their importance, it has been estimated that past landslide and landslide potential maps cover less than 1% of the slopes in these landmasses. Systematic information on the type, abundance, and distribution of existing landslides is lacking. Even in countries where landslide information is abundant (e.g. Italy), the vast majority of landslides caused by meteorological (intense or prolonged rainfall, rapid snowmelt) or geophysical (earthquake) triggers go undetected. This paucity of knowledge has consequences on the design of effective remedial and mitigation measures. Systematic use of Earth observation (EO) data and technologies can contribute effectively to detect, map, and monitor landslides, and landslide prone hillsides, in different physiographic and climatic regions. The CEOS (Committee on Earth Observation Satellites) Working Group on Disasters has recently launched a Landslide Pilot (period 2017-2019) with the aim to demonstrate the effective exploitation of satellite EO across the full cycle of landslide disaster risk management, including preparedness, response, and recovery at global, regional, and local scales, with a distinct multi-hazard focus on cascading impacts and risks. The Landslide Pilot is focusing efforts on three objectives: 1. Establish effective practices for merging different Earth Observation data (e.g. optical and radar) to better monitor and map landslide activity over time and space. 2. Demonstrate how landslide products, models, and services can support disaster risk management for multi-hazard and cascading landslide events. 3. Engage and partner with data brokers and end users to understand requirements and user expectations and get feedback through the activities described in objectives 1-2. The Landslide Pilot was endorsed in April 2016 and work
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Zieher, Thomas; Perzl, Frank; Rössel, Monika; Rutzinger, Martin; Meißl, Gertraud; Markart, Gerhard; Geitner, Clemens
2016-04-01
Geomorphological landslide inventories provide crucial input data for any study on the assessment of landslide susceptibility, hazard or risk. Several approaches for assessing landslide susceptibility have been proposed to identify areas particularly vulnerable to this natural hazard. What they have in common is the need for data of observed landslides. Therefore the first step of any study on landslide susceptibility is usually the compilation of a geomorphological landslide inventory using a geographical information system. Recent research has proved the feasibility of orthophoto interpretation for the preparation of an inventory aimed at the delineation of landslides with the use of distinctive signs in the imagery data. In this study a multi-annual landslide inventory focusing on shallow landslides (i.e. translational soil slides of 0-2 m in depth) was compiled for two study areas in Vorarlberg (Austria) from the interpretation of nine orthophoto series. In addition, derivatives of two generations of airborne laser scanning data aided the mapping procedure. Landslide scar areas were delineated on the basis of a high-resolution differential digital terrain model. The derivation of landslide volumes, depths and depth-to-length ratios are discussed. Results show that most mapped landslides meet the definition of a shallow landslide. The inventory therefore provides the data basis for the assessment of shallow landslide susceptibility and allows for the application of various modelling techniques.
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Landslide Economics: Concepts and Case Studies
Klose, Martin; Damm, Bodo
2015-04-01
Landslide economics is vital for fundamental understanding of landslide risk as dealing with two important topics: (i) impact assessment, either as damage statistics or cost modeling, and (ii) vulnerability assessment, i.e., the study of exposure, sensitivity, and resilience to landslide damage, ideally from both sociotechnical and financial perspective (e.g., Crovelli and Coe, 2009; Wills et al., 2014). Many aspects addressed in landslide economics have direct influence on landslide risk, including: (i) human activity is often a major causative factor of landslides, not only by predisposing or triggering them, but also as a result of inadequate (low-cost) landslide mitigation; (ii) the level of tolerable or acceptable risk, a measure driving a large part of landslide costs in industrialized countries, is highly variable, differing between individuals, public or private organizations, and societies, with its nature being to change over time; and (iii) decision makers are faced with finding the right balance in landslide mitigation, thus need to weight diverse geological and socioeconomic factors that control its effectiveness in both technical and financial terms (e.g., Klose et al., 2014a). A large part of the complexity in assessing landslide risk as measured by economic costs is due to unique problems in understanding of (i) what types of landslide damage affect human activity and infrastructure in which way, (ii) how society contributes and responds to various kinds of damage, and (iii) how landslide damage is valued in monetary terms. Landslide economics shows the potential to take account of these sociocultural factors to the benefit of risk analysis (e.g., Klose et al., 2014b). The present contribution introduces local and regional case studies in which different economic issues of landslide risk are highlighted using the example of public infrastructures in NW Germany. A special focus is on the following topics: (i) risk culture and created risk, (ii
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Landslides of Palestinian Region
Alwahsh, H.
2013-12-01
Natural disasters are extreme sudden events caused by environmental and natural actors that take away the lives of many thousands of people each year and damage large amount of properties. They strike anywhere on earth, often without any warning. A risk maps of natural disaster are very useful to identify the places that might be adversely affected in the event of natural disaster. The earthquakes are one of natural disaster that have the greatest hazards and will cause loss of life and properties due to damaging the structures of building, dams, bridges. In addition, it will affect local geology and soil conditions. The site effects play an important role in earthquake risk because of its amplification or damping simulation. Another parameter in developing risk map is landslide, which is also one of the most important topics in site effect hazards. Palestine region has been suffering landslide hazards because of the topographical and geological conditions of this region. Most Palestine consists of mountainous area, which has great steep slopes and the type of soil is mainly grayish to yellowish silty clay (Marl Soil). Due to the above mentioned factors many landslides have been occurred from Negev south to the northern borders of Palestine. An example of huge and destruction landslide in a Palestine authority is the landslide in the White Mountain area in the city of Nablus, which occurred in 1997. The geotechnical and geophysical investigation as well as slope stability analysis should be considered in making landslide maps that are necessary to develop risk levels of the natural disaster. Landslides occurred in slopes that are created naturally or by human beings. Failure of soil mass occurs, and hence landslide of soil mass happen due to sliding of soil mass along a plane or curved surface. In general, the slopes become unstable when the shear stresses (driving force) generated in the soil mass exceed the available shearing resistance on the rupture surface
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Løvholt, F.; Kim, J.; Laberg, J. S.
2016-12-01
The continental margin offshore Norway have experienced a range of giant submarine landslides having volumes ranging from hundreds to thousands of km3. The most recent and well documented of these events, are the 4500 BP Trænadjupet and the 8100 BP Storegga landslides. Both of these landslides are clay-rich, and involve common features such as retrogressive mass and momentum release mechanisms and weak layers that affect the tsunami generation. The retrogressive behaviour involved the release of several slide blocks which made the multistage failure and landslide evolution complex. The Storegga Slide reveals a rich and well documented onshore footprint in terms of paleotsunami deposits along the coastlines of Denmark, UK, the Faroe Islands, and Norway. In striking contrast, there exists no firm evidence of similar paleotsunami deposits from the younger Trænadjupet landslide. Here, we use a suit of new retrogressive and viscoplastic landslide models to simulate the run-out of both of these landslide events, and then couple the landslide to dispersive tsunami models. By using the new landslide models, we are able to obtain a better agreement with the observed paleotsunami deposits from the Storegga Slide compared to previous studies, and at the same time, to link the results to a landslide model that comply better with the slide morphology. Using the landslide model and soil parameters established for the Storegga Slide as the starting point, we set up a similar set of model scenarios for the Trænadjupet Slide. We discuss how the scenarios for the Trænadjupet landslide with different soil parameters produce different landslide velocities and tsunami heights. We then compare the resulting tsunami heights with constraints from the lack of onshore tsunami observations taking into account the contemporary shoreline position. Finally we briefly discuss the findings from the modeling in terms of both differences in tsunami observations and landslide morphology. The
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Albrecht, F.; Hölbling, D.; Friedl, B.
2017-09-01
Landslide mapping benefits from the ever increasing availability of Earth Observation (EO) data resulting from programmes like the Copernicus Sentinel missions and improved infrastructure for data access. However, there arises the need for improved automated landslide information extraction processes from EO data while the dominant method is still manual delineation. Object-based image analysis (OBIA) provides the means for the fast and efficient extraction of landslide information. To prove its quality, automated results are often compared to manually delineated landslide maps. Although there is awareness of the uncertainties inherent in manual delineations, there is a lack of understanding how they affect the levels of agreement in a direct comparison of OBIA-derived landslide maps and manually derived landslide maps. In order to provide an improved reference, we present a fuzzy approach for the manual delineation of landslides on optical satellite images, thereby making the inherent uncertainties of the delineation explicit. The fuzzy manual delineation and the OBIA classification are compared by accuracy metrics accepted in the remote sensing community. We have tested this approach for high resolution (HR) satellite images of three large landslides in Austria and Italy. We were able to show that the deviation of the OBIA result from the manual delineation can mainly be attributed to the uncertainty inherent in the manual delineation process, a relevant issue for the design of validation processes for OBIA-derived landslide maps.
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Directory of Open Access Journals (Sweden)
Dan Zarojanu
2017-07-01
Full Text Available In the county of Suceava, the landslides are a real and permanent problem. This paper presents the observations of landslides over the last 30 years in Suceava County, especially their morphology, theirs causes and the landslide stopping measures. It presents also several details regarding the lanslides from the town of Suceava, of Frasin and the village of Brodina.
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Directory of Open Access Journals (Sweden)
F. Albrecht
2017-09-01
Full Text Available Landslide mapping benefits from the ever increasing availability of Earth Observation (EO data resulting from programmes like the Copernicus Sentinel missions and improved infrastructure for data access. However, there arises the need for improved automated landslide information extraction processes from EO data while the dominant method is still manual delineation. Object-based image analysis (OBIA provides the means for the fast and efficient extraction of landslide information. To prove its quality, automated results are often compared to manually delineated landslide maps. Although there is awareness of the uncertainties inherent in manual delineations, there is a lack of understanding how they affect the levels of agreement in a direct comparison of OBIA-derived landslide maps and manually derived landslide maps. In order to provide an improved reference, we present a fuzzy approach for the manual delineation of landslides on optical satellite images, thereby making the inherent uncertainties of the delineation explicit. The fuzzy manual delineation and the OBIA classification are compared by accuracy metrics accepted in the remote sensing community. We have tested this approach for high resolution (HR satellite images of three large landslides in Austria and Italy. We were able to show that the deviation of the OBIA result from the manual delineation can mainly be attributed to the uncertainty inherent in the manual delineation process, a relevant issue for the design of validation processes for OBIA-derived landslide maps.
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Lin, Ying-Tong; Chang, Kuo-Chen; Yang, Ci-Jian
2017-04-01
As the result of global warming in the past decades, Taiwan has experienced more and more extreme typhoons with hazardous massive landslides. In this study, we use object-oriented analysis method to classify landslide area at Baolai village by using Formosat-2 satellite images. We used for multiresolution segmented to generate the blocks, and used hierarchical logic to classified 5 different kinds of features. After that, classification the landslide into different type of landslide. Beside, we use stochastic procedure to integrate landslide susceptibility maps. This study assumed that in the extreme event, 2009 Typhoon Morakot, which precipitation goes to 1991.5mm in 5 days, and the highest landslide susceptible area. The results show that study area's landslide area was greatly changes, most of landslide was erosion by gully and made dip slope slide, or erosion by the stream, especially at undercut bank. From the landslide susceptibility maps, we know that the old landslide area have high potential to occur landslides in the extreme event. This study demonstrates the changing of landslide area and the landslide susceptible area. Keywords: Formosat-2, object-oriented, segmentation, classification, landslide, Baolai Village, SW Taiwan, FS
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International Nuclear Information System (INIS)
Liu Jianjun
2000-01-01
The author briefly describes the genesis and ore-formation mechanism of paleo-channel sandstone-type uranium deposit in Nuheting area. Techniques such as remote sensing digital image data processing and data enhancement, as well as 3-dimension quantitative analysis of drill hole data are applied to extract information on metallogenic environment of paleo-channel sandstone-type uranium deposit and the distribution of paleo-channel
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Numerical modeling of landslides and generated seismic waves: The Bingham Canyon Mine landslides
Miallot, H.; Mangeney, A.; Capdeville, Y.; Hibert, C.
2016-12-01
Landslides are important natural hazards and key erosion processes. They create long period surface waves that can be recorded by regional and global seismic networks. The seismic signals are generated by acceleration/deceleration of the mass sliding over the topography. They consist in a unique and powerful tool to detect, characterize and quantify the landslide dynamics. We investigate here the processes at work during the two massive landslides that struck the Bingham Canyon Mine on the 10th April 2013. We carry a combined analysis of the generated seismic signals and the landslide processes computed with a 3D modeling on a complex topography. Forces computed by broadband seismic waveform inversion are used to constrain the study and particularly the force-source and the bulk dynamic. The source time function are obtained by a 3D model (Shaltop) where rheological parameters can be adjusted. We first investigate the influence of the initial shape of the sliding mass which strongly affects the whole landslide dynamic. We also see that the initial shape of the source mass of the first landslide constrains pretty well the second landslide source mass. We then investigate the effect of a rheological parameter, the frictional angle, that strongly influences the resulted computed seismic source function. We test here numerous friction laws as the frictional Coulomb law and a velocity-weakening friction law. Our results show that the force waveform fitting the observed data is highly variable depending on these different choices.
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Landsliding in partially saturated materials
Godt, J.W.; Baum, R.L.; Lu, N.
2009-01-01
[1] Rainfall-induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore-water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials. Copyright 2009 by the American Geophysical Union.
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Sinclair, L.; Conner, P.; le Roux, J.; Finley, T.
2015-12-01
The International Emergency Disasters Database indicates that a total of 482 people have been killed and another 27,530 have been affected by landslides in Rwanda and Uganda, although the actual numbers are thought to be much higher. Data for individual countries are poorly tracked, but hotspots for devastating landslides occur throughout Rwanda and Uganda due to the local topography and soil type, intense rainfall events, and deforestation. In spite of this, there has been little research in this region that utilizes satellite imagery to estimate areas susceptible to landslides. This project utilized Landsat 8 Operational Land Imager (OLI) data and Google Earth to identify landslides that occurred within the study area. These landslides were then added to SERVIR's Global Landslide Catalog (GLC). Next, Landsat 8 OLI, the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM), and Shuttle Radar Topography Mission Version 2 (SRTM V2) data were used to create a Landslide Susceptibility Map. This was combined with population data from the Socioeconomic Data and Applications Center (SEDAC) to create a Landslide Hazard map. A preliminary assessment of the relative performance of GPM and TRMM in identifying landslide conditions was also performed. The additions to the GLC, the Landslide Susceptibility Map, the Landslide Hazard Map, and the preliminary assessment of satellite rainfall performance will be used by SERVIR and the Regional Centre for Mapping of Resources for Development (RCMRD) for disaster risk management, land use planning, and determining landslide conditions and moisture thresholds.
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Van Den Eeckhaut, M.; Verstraeten, G.; Poesen, J.
2007-09-01
This study attempts to reconstruct the history of the Collinabos landslide, a landslide with a fresh morphology that is representative for more than 150 dormant, deep-seated (> 3 m) landslides in the Flemish Ardennes (Belgium). A geomorphological map was created based on LIDAR (Light Detection and Ranging)-derived maps and detailed field surveys. The map showed that the landslide consisted of three zones with significant differences in surface topography. The northern landslide zone 1 is characterised by at least five reverse slopes, whereas zones 2 and 3, the southern landslide zones, have only two reverse slopes and a convex foot. Electric resistivity profiles measured in zones 1 and 2 revealed that the differences in surface topography were not related to differences in internal structure as both parts of the landslide were initiated as a rotational earth slide with a surface of rupture at 15 m deep, where the displaced material broke apart in two blocks. However, two shear surfaces of reactivations within landslide debris were only distinguished in the accumulation area of zone 1. The observed differences in surface morphology can be caused by a temporary conversion of a forest into cropland in zone 2. It is suggested that reverse slopes of smaller reactivations within landslide debris were obliterated during the agricultural activities. AMS radiocarbon dating of organic material found in ponds located in reverse slopes generally resulted in relatively recent dates (i.e. 1400-1950 Cal AD) suggesting that several of the small local reactivations occurred in that period. One dating at 8700-8440 Cal BP of organic matter collected in a reverse slope in zone 1 suggests that an initiation under periglacial conditions cannot be excluded for the Collinabos landslide. By combining different technologies, this study provides valuable information for a better understanding of dormant landslides.
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Mohammed, F.
2016-12-01
Landslide hazards such as fast-moving debris flows, slow-moving landslides, and other mass flows cause numerous fatalities, injuries, and damage. Landslide occurrences in fjords, bays, and lakes can additionally generate tsunamis with locally extremely high wave heights and runups. Two-dimensional depth-averaged models can successfully simulate the entire lifecycle of the three-dimensional landslide dynamics and tsunami propagation efficiently and accurately with the appropriate assumptions. Landslide rheology is defined using viscous fluids, visco-plastic fluids, and granular material to account for the possible landslide source materials. Saturated and unsaturated rheologies are further included to simulate debris flow, debris avalanches, mudflows, and rockslides respectively. The models are obtained by reducing the fully three-dimensional Navier-Stokes equations with the internal rheological definition of the landslide material, the water body, and appropriate scaling assumptions to obtain the depth-averaged two-dimensional models. The landslide and tsunami models are coupled to include the interaction between the landslide and the water body for tsunami generation. The reduced models are solved numerically with a fast semi-implicit finite-volume, shock-capturing based algorithm. The well-balanced, positivity preserving algorithm accurately accounts for wet-dry interface transition for the landslide runout, landslide-water body interface, and the tsunami wave flooding on land. The models are implemented as a General-Purpose computing on Graphics Processing Unit-based (GPGPU) suite of models, either coupled or run independently within the suite. The GPGPU implementation provides up to 1000 times speedup over a CPU-based serial computation. This enables simulations of multiple scenarios of hazard realizations that provides a basis for a probabilistic hazard assessment. The models have been successfully validated against experiments, past studies, and field data
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Global Landslide Catalog Export
National Aeronautics and Space Administration — The Global Landslide Catalog (GLC) was developed with the goal of identifying rainfall-triggered landslide events around the world, regardless of size, impacts or...
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An analysis of on time evolution of landslide
Tsai, Chienwei; Lien, Huipang
2017-04-01
In recent years, the extreme hydrological phenomenon in Taiwan is obvious. Because the increase of heavy rainfall frequency has resulted in severe landslide disaster, the watershed management is very important and how to make the most effective governance within the limited funds is the key point. In recent years many scholars to develop empirical models said that virtually rainfall factors exist and as long as rainfall conditions are met the minimum requirements of the model, landslide will occur. However, rainfall is one of the elements to the landslide, but not the only one element. Rainfall, geology and earthquake all contributed to the landslide as well. Preliminary research found that many landslides occur at the same location constantly and after repeating landslide, the slope had the characteristic of landslide immunity over time, even if the rainfall exceeded the standard, the landslide could not be triggered in the near term. This study investigated the surface conditions of slope that occur repeated landslide. It is difficult to be the basis of subsequent anti-disaster if making rainfall is the only condition to contribute to the landslide. This study analyzes 50 landslides in 2004 2013. Repeated landslide is defined as existed landslide in satellite images of reference period which it's bare area is shrinking or disappearing gradually but the restoration occur landslide again in some period time. The statistical analysis of the study found that 96% of landslide has repeated landslide and on average repeated landslide occurs 3.4 years in 10 years by one year as the unit. The highest of repeated landslide happened in 2010. It would presume that Typhoon Morakot in 2010 brought torrential rain which suffered southern mountain areas severely so the areas occurred repeated landslide.
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Global Landslide Hazard Distribution
National Aeronautics and Space Administration — Global Landslide Hazard Distribution is a 2.5 minute grid of global landslide and snow avalanche hazards based upon work of the Norwegian Geotechnical Institute...
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Landslide triggering by rain infiltration
Iverson, Richard M.
2000-01-01
Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where D0 is the maximum hydraulic diffusivity of the soil and A is the catchment area that potentially affects groundwater pressures at a prospective landslide slip surface location with areal coordinates x, y and depth H. Times greater than A/D0 are necessary for establishment of steady background water pressures that develop at (x, y, H) in response to rainfall averaged over periods that commonly range from days to many decades. These steady groundwater pressures influence the propensity for landsliding at (x, y, H), but they do not trigger slope failure. Failure results from rainfall over a typically shorter timescale H2/D0 associated with transient pore pressure transmission during and following storms. Commonly, this timescale ranges from minutes to months. The shortest timescale affecting landslide responses to rainfall is √(H/g), where g is the magnitude of gravitational acceleration. Postfailure landslide motion occurs on this timescale, which indicates that the thinnest landslides accelerate most quickly if all other factors are constant. Effects of hydrologic processes on landslide processes across these diverse timescales are encapsulated by a response function, R(t*) = √(t*/π) exp (-1/t*) - erfc (1/√t*), which depends only on normalized time, t*. Use of R(t*) in conjunction with topographic data, rainfall intensity and duration information, an infinite-slope failure criterion, and Newton's second law predicts the timing, depth, and acceleration of rainfall-triggered landslides. Data from contrasting landslides that exhibit rapid, shallow
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Crozier, M. J.
2017-10-01
Multiple-occurrence regional landslide events (MORLEs) consist of hundreds to thousands of shallow landslides occurring more or less simultaneously within defined areas, ranging from tens to thousands of square kilometres. While MORLEs can be triggered by rainstorms and earthquakes, this paper is confined to those landslide events triggered by rainstorms. Globally, MORLEs occur in a range of geological settings in areas of moderate to steep slopes subject to intense rainstorms. Individual landslides in rainstorm-triggered events are dominantly small, shallow debris and earth flows, and debris and earth slides involving regolith or weathered bedrock. The model used to characterise these events assumes that energy distribution within the event area is represented on the land surface by a cell structure; with maximum energy expenditure within an identifiable core and rapid dissipation concentrically away from the centre. The version of the model presented here has been developed for rainfall-triggered landslide events. It proposes that rainfall intensity can be used to determine different critical landslide response zones within the cell (referred to as core, middle, and periphery zones). These zones are most readily distinguished by two conditions: the proportion of the slope that fails and the particular type of the slope stability factor that assumes dominance in determining specific sites of landslide occurrence. The latter condition means that the power of any slope stability factor to distinguish between stable and unstable sites varies throughout the affected area in accordance with the landslide response zones within the cell; certain factors critical for determining the location of landslide sites in one part of the event area have little influence in other parts of the event area. The implication is that landslide susceptibility maps (and subsequently derived mitigation measures) based on conventional slope stability factors may have only limited validity
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Lithofacies-paleo-geography and uranium sedimentary facies in Hailar basin
International Nuclear Information System (INIS)
Qi Fucheng
1992-01-01
Cretaceous-Tertiary sedimentary paleo-structure and lithofacies-paleo-geography in Hailar Basin are described. Taking Chenqi coal field as an example, the sedimentary facies pattern of coal-bearing series characterized by alternating sedimentation of fluviatile and lacustrine-swampy facies is reconstructed. It is pointed out that this sedimentary facies not only controls the sedimentation and distribution of syngenetic uranium mineralization, but also is a favourable place that converges uranium-bearing solution and reduces and precipitates uranium for the second time in epigenetic mineralization
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Radiometric method and abnormal explanation of landslide survey
International Nuclear Information System (INIS)
Ye Shulin; Sun Zhanxue; Luo Liangsheng
2003-01-01
Radioactivity exploration mechanism of landslide is researched. Radioactive measure technical and its anomaly explanation models of application is introduced. Test verification result of landslide body geological form (boundary and landslide body thickness) in the district of Wanzhou 233 of Chongqing city ancients landslide and the Yunyang new county Zhaiba landslide shows, it can be used in determining the body boundary (reason) line, investigating the underground current direction and landslide body moving direction, explaining that calculation of weathered zone thickness of landslide body. It can also increase the geological effect of landslide exploration in adaption with geology and drilling
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Directory of Open Access Journals (Sweden)
S. Pereira
2012-04-01
Full Text Available The aim of this study is to identify the landslide predisposing factors' combination using a bivariate statistical model that best predicts landslide susceptibility. The best model is one that has simultaneously good performance in terms of suitability and predictive power and has been developed using variables that are conditionally independent. The study area is the Santa Marta de Penaguião council (70 km2 located in the Northern Portugal.
In order to identify the best combination of landslide predisposing factors, all possible combinations using up to seven predisposing factors were performed, which resulted in 120 predictions that were assessed with a landside inventory containing 767 shallow translational slides. The best landslide susceptibility model was selected according to the model degree of fitness and on the basis of a conditional independence criterion. The best model was developed with only three landslide predisposing factors (slope angle, inverse wetness index, and land use and was compared with a model developed using all seven landslide predisposing factors.
Results showed that it is possible to produce a reliable landslide susceptibility model using fewer landslide predisposing factors, which contributes towards higher conditional independence.
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Directory of Open Access Journals (Sweden)
Ali Mohammadi Torkashvand
2014-12-01
Full Text Available One of the risks to threaten mountainous areas is that hillslope instability caused damage to lands. One of the most dangerous instabilities is mass movement and much movement occurs due to slip. The aim of this study is zonation of landslide hazards in a basin of the Ardebil province, the eastern slopes of Sabalan, Iran. Geological and geomorphologic conditions, climate and type of land use have caused susceptibility of this watershed to landslides. Firstly, maps of the main factors affecting landslide occurrence including slope, distance from faults, lithology, elevation and precipitation were prepared and digitized. Then, by using interpretation of aerial photos and satellite images and field views, the ground truth map of landslides was prepared. Each basic layer (factor and landslide map were integrated to compute the numeric value of each factor with the help of a Landslide Numerical Risk Factor (LNRF model and landslide occurrence percent obtained in different units from each of the maps. Finally, with overlapping different data layers, a landslide hazard zonation map was prepared. Results showed that 67.85% of the basin has high instability, 7.76% moderate instability and 24.39% low instability.
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Yavari Ramsheh, S.; Ataie-Ashtiani, B.
2017-12-01
Recent studies revealed that landslide-generated waves (LGWs) impose the largest tsunami hazard to our shorelines although earthquake-generated waves (EGWs) occur more often. Also, EGWs are commonly followed by a large number of landslide hazards. Dam reservoirs are more vulnerable to landslide events due to being located in mountainous areas. Accurate estimation of such hazards and their destructive consequences help authorities to reduce their risks by constructive measures. In this regard, a two-layer two-phase Coulomb mixture flow (2LCMFlow) model is applied to investigate the effects of landslide characteristics on LGWs for a real-sized simplification of the Maku dam reservoir, located in the North of Iran. A sensitivity analysis is performed on the role of landslide rheological and constitutive parameters and its initial submergence in LGW characteristics and formation patterns. The numerical results show that for a subaerial (SAL), a semi-submerged (SSL), and a submarine landslide (SML) with the same initial geometry, the SSLs can create the largest wave crest, up to 60% larger than SALs, for dense material. However, SMLs generally create the largest wave troughs and SALs travel the maximum runout distances beneath the water. Regarding the two-phase (solid-liquid) nature of the landslide, when interestial water is isolated from the water layer along the water/landslide interface, a LGW with up to 30% higher wave crest can be created. In this condition, increasing the pore water pressure within the granular layer results in up to 35% higher wave trough and 40% lower wave crest at the same time. These results signify the importance of appropriate description of two-phase nature and rheological behavior of landslides in accurate estimation of LGWs which demands further numerical, physical, and field studies about such phenomena.
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Valenciano, J.; Angenent, J.; Marshall, J. S.; Clark, K.; Litchfield, N. J.
2017-12-01
The Hikurangi subduction margin along the east coast of the North Island, New Zealand accommodates oblique convergence of the Pacific Plate westward beneath the Australian plate at 45 mm/yr. Pronounced forearc uplift occurs at the southern end of the margin along the Wairarapa coast, onshore of the subducting Hikurangi plateau. Along a narrow coastal lowland, a series of uplifted Holocene marine terraces and beach ridges preserve a geologic record of prehistoric coseismic uplift events. In January 2017, we participated in the Research Experience for Undergraduates (REU) program of the NSF SHIRE Project (Subduction at Hikurangi Integrated Research Experiment). We visited multiple coastal sites for reconnaissance fieldwork to select locations for future in-depth study. For the coastline between Flat Point and Te Kaukau Point, we used airborne LiDAR data provided by Land Information New Zealand (LINZ) to create ArcGIS digital terrain models for mapping and correlating uplifted paleo-shorelines. Terrace elevations derived from the LiDAR data were calibrated through the use of Real Time Kinematic (RTK) GPS surveying at one field site (Glenburn Station). Prior field mapping and radiocarbon dating results (Berryman et al., 2001; Litchfield and Clark, 2015) were used to guide our LiDAR mapping efforts. The resultant maps show between four and seven uplifted terraces and associated beach ridges along this coastal segment. At some sites, terrace mapping and lateral correlation are impeded by discontinuous exposures and the presence of landslide debris, alluvial fan deposits, and sand dunes. Tectonic uplift along the southern Hikurangi margin is generated by a complex interaction between deep megathrust slip and shallow upper-plate faulting. Each uplifted Holocene paleo-shoreline is interpreted to represent a single coseismic uplift event. Continued mapping, surveying, and age dating may help differentiate between very large margin-wide megathrust earthquakes (M8.0-9.0+) and
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Oh, Hyun-Joo; Pradhan, Biswajeet
2011-09-01
This paper presents landslide-susceptibility mapping using an adaptive neuro-fuzzy inference system (ANFIS) using a geographic information system (GIS) environment. In the first stage, landslide locations from the study area were identified by interpreting aerial photographs and supported by an extensive field survey. In the second stage, landslide-related conditioning factors such as altitude, slope angle, plan curvature, distance to drainage, distance to road, soil texture and stream power index (SPI) were extracted from the topographic and soil maps. Then, landslide-susceptible areas were analyzed by the ANFIS approach and mapped using landslide-conditioning factors. In particular, various membership functions (MFs) were applied for the landslide-susceptibility mapping and their results were compared with the field-verified landslide locations. Additionally, the receiver operating characteristics (ROC) curve for all landslide susceptibility maps were drawn and the areas under curve values were calculated. The ROC curve technique is based on the plotting of model sensitivity — true positive fraction values calculated for different threshold values, versus model specificity — true negative fraction values, on a graph. Landslide test locations that were not used during the ANFIS modeling purpose were used to validate the landslide susceptibility maps. The validation results revealed that the susceptibility maps constructed by the ANFIS predictive models using triangular, trapezoidal, generalized bell and polynomial MFs produced reasonable results (84.39%), which can be used for preliminary land-use planning. Finally, the authors concluded that ANFIS is a very useful and an effective tool in regional landslide susceptibility assessment.
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Application of radioisotopes in investigating landslides
International Nuclear Information System (INIS)
Turcek, P.; Ravinger, R.; Hulla, J.
1983-01-01
Radiotracer techniques have been used for geological investigations of landslide areas. It was possible to localize a landslide area and a weakened zone. Based on the results forecasts have been made of further possible landslide in the area
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Landslides Hazard Assessment Using Different Approaches
Directory of Open Access Journals (Sweden)
Coman Cristina
2017-06-01
Full Text Available Romania represents one of Europe’s countries with high landslides occurrence frequency. Landslide hazard maps are designed by considering the interaction of several factors which, by their joint action may affect the equilibrium state of the natural slopes. The aim of this paper is landslides hazard assessment using the methodology provided by the Romanian national legislation and a very largely used statistical method. The final results of these two analyses are quantitative or semi-quantitative landslides hazard maps, created in geographic information system environment. The data base used for this purpose includes: geological and hydrogeological data, digital terrain model, hydrological data, land use, seismic action, anthropic action and an inventory of active landslides. The GIS landslides hazard models were built for the geographical area of the Iasi city, located in the north-east side of Romania.
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Mechanical-mathematical modeling for landslide process
Svalova, V.
2009-04-01
Landslides process is one of the most widespread and dangerous processes in the urbanized territories. In Moscow the landslips occupy about 3 % of the most valuable territory of city. There are near 20 places of deep landslides and some hundreds of shallow landslides in Moscow. In Russia many towns are located near rivers on high coastal sides. There are many churches and historical buildings on high costs of Volga River and Moscow River. The organization of monitoring is necessary for maintenance of normal functioning of city infrastructure in a coastal zone and duly realization of effective protective actions. Last years the landslide process activization took place in Moscow. The right coast of river Moscow on its significant extent within the limits of city Moscow is struck by deep block landslides with depth up to 90 - 100 m which formation occurred in preglacial time with basis of sliding in Callovian-Oxford clays of Jurassic system on 25 - 30 m below modern level of the river . One of landslide sites is on Vorob'evy mountains, on a high slope of the right coast of the river Moscow with height of 65 m. There is a historical monument - «Andreevsky monastery», based in 1648. Also there are the complex of buildings of Presidium of the Russian Academy of Sciences, constructed in 70 - 80th years of 20-th century, bridge with station of underground "Vorob'evy mountain", constructions of sport complexes. Landslide slope is in active condition, and there are many attributes of activization of deep block landslide. In June 2007 a rather big landslide took place there near ski-jump. Another landslide site is in a southeast part of Moscow, occupying the right coast of river Moscow near museum - reserve "Kolomenskoye". The slope in this place has height of 38 - 40 m. Motions of deep landslips have begun from 1960 in connection with construction of collectors. In 70th years of XX century there was a strong activization of a slope with formation of cracks by extent up to
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Diagenetic paleo-conditions of the 'Francevillien A' (2.4-2.1 Gy) in Gabon
International Nuclear Information System (INIS)
Ossa Ossa, F.; El Albani, A.; Beaufort, D.; Meunier, A.; Fontaine, C.; Gauthier-Lafaye, F.
2009-01-01
The authors report a precise analysis of the geological structure and paleo-conditions of different parts of the Franceville paleo-proterozoic basin where manganese and uranium can be found, and where the presence of natural nuclear reactors in some geological formations make the Franceville basin a place of interest for the exploration of natural resources and for the paleo-migrations of 'radioactive wastes'. They tried to see whether clayey transformations are related to burying diagenesis or to hot fluid circulations induced by natural nuclear reactors
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Landslide Susceptibility Index Determination Using Aritificial Neural Network
Kawabata, D.; Bandibas, J.; Urai, M.
2004-12-01
The occurrence of landslide is the result of the interaction of complex and diverse environmental factors. The geomorphic features, rock types and geologic structure are especially important base factors of the landslide occurrence. Generating landslide susceptibility index by defining the relationship between landslide occurrence and that base factors using conventional mathematical and statistical methods is very difficult and inaccurate. This study focuses on generating landslide susceptibility index using artificial neural networks in Southern Japanese Alps. The training data are geomorphic (e.g. altitude, slope and aspect) and geologic parameters (e.g. rock type, distance from geologic boundary and geologic dip-strike angle) and landslides. Artificial neural network structure and training scheme are formulated to generate the index. Data from areas with and without landslide occurrences are used to train the network. The network is trained to output 1 when the input data are from areas with landslides and 0 when no landslide occurred. The trained network generates an output ranging from 0 to 1 reflecting the possibility of landslide occurrence based on the inputted data. Output values nearer to 1 means higher possibility of landslide occurrence. The artificial neural network model is incorporated into the GIS software to generate a landslide susceptibility map.
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Current status on techniques for determining paleo-temperature using geothermometer
International Nuclear Information System (INIS)
Kanazawa, Sunao; Oikawa, Teruki; Umeda, Koji; Tomiyama, Shingo
2005-01-01
Development of the research technologies for geotectonic events has been carried out to evaluate the long-term stability of geological environment. In terms of the effects of geothermal activity, it is necessary to estimate the geothermal regime and thermal history on any given site. This paper describes the current status on techniques for determining paleo-temperature using geothermometer, and presents a concept of the systematic research techniques. The application of geothermometer, especially thermochronology, has been effective in the studies on the cooling history of geological body and the paleo-geothermal structure at depth. (author)
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Paleo-eskimo mtDNA genome reveals matrilineal discontinuity in Greenland
DEFF Research Database (Denmark)
Gilbert, Marcus Thomas Pius; Kivisild, Toomas; Grønnow, Bjarne
2008-01-01
a mitochondrial genome from a Paleo-Eskimo human by using 3400-to 4500-year-old frozen hair excavated from an early Greenlandic Saqqaq settlement. The sample is distinct from modern Native Americans and Neo-Eskimos, falling within haplogroup D2a1, a group previously observed among modern Aleuts and Siberian......The Paleo-Eskimo Saqqaq and Independence I cultures, documented from archaeological remains in Northern Canada and Greenland, represent the earliest human expansion into the New World's northern extremes. However, their origin and genetic relationship to later cultures are unknown. We sequenced...
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A logical framework for ranking landslide inventory maps
Santangelo, Michele; Fiorucci, Federica; Bucci, Francesco; Cardinali, Mauro; Ardizzone, Francesca; Marchesini, Ivan; Cesare Mondini, Alessandro; Reichenbach, Paola; Rossi, Mauro; Guzzetti, Fausto
2014-05-01
Landslides inventory maps are essential for quantitative landslide hazard and risk assessments, and for geomorphological and ecological studies. Landslide maps, including geomorphological, event based, multi-temporal, and seasonal inventory maps, are most commonly prepared through the visual interpretation of (i) monoscopic and stereoscopic aerial photographs, (ii) satellite images, (iii) LiDAR derived images, aided by more or less extensive field surveys. Landslide inventory maps are the basic information for a number of different scientific, technical and civil protection purposes, such as: (i) quantitative geomorphic analyses, (ii) erosion studies, (iii) deriving landslide statistics, (iv) urban development planning (v) landslide susceptibility, hazard and risk evaluation, and (vi) landslide monitoring systems. Despite several decades of activity in landslide inventory making, still no worldwide-accepted standards, best practices and protocols exist for the ranking and the production of landslide inventory maps. Standards for the preparation (and/or ranking) of landslide inventories should indicate the minimum amount of information for a landslide inventory map, given the scale, the type of images, the instrumentation available, and the available ancillary data. We recently attempted at a systematic description and evaluation of a total of 22 geomorphological inventories, 6 multi-temporal inventories, 10 event inventories, and 3 seasonal inventories, in the scale range between 1:10,000 and 1:500,000, prepared for areas in different geological and geomorphological settings. All of the analysed inventories were carried out by using image interpretation techniques, or field surveys. Firstly, a detailed characterisation was performed for each landslide inventory, mainly collecting metadata related (i) to the amount of information used for preparing the landslide inventory (i.e. images used, instrumentation, ancillary data, digitalisation method, legend, validation
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Evaluation of landslide monitoring in the Polish Carpathians
Collins, Brian D.; Baum, Rex L.; Mrozek, Teresa; Nescieruk, Piotr; Perski, Zbigniew; Raczkowski, Wojciech; Graniczny, Marek
2011-01-01
In response to the June 15, 2010 request from the Polish Geological Institute (PGI) to the U.S. Geological Survey (USGS) for assistance and advice regarding real-time landslide monitoring, landslide specialists from the USGS Landslide Hazard Program visited PGI headquarters and field sites in September 2010. During our visit we became familiar with characteristics of landslides in the Polish Carpathians, reviewed PGI monitoring techniques, and assessed needs for monitoring at recently activated landslides. Visits to several landslides that are monitored by PGI (the Just, Hańczowa, Szymbark, Siercza and Łasńica landslides) revealed that current data collection (monthly GPS and inclinometer surveys, hourly piezometers readings) is generally sufficient for collecting basic information about landslide displacement, depth, and groundwater conditions. Large landslides are typically hydrologically complex, and we would expect such complexity in Carpathian landslides, given the alternating shale and sandstone stratigraphy and complex geologic structures of the flysch bedrock. Consequently groundwater observations could be improved by installing several piezometers that sample the basal shear zone of each landslide being monitored by PGI. These could be supplemented by additional piezometers at shallower depths to help clarify general flow directions and hydraulic gradients. Remedial works at Hańczowa
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Directory of Open Access Journals (Sweden)
Qianqian Wang
2015-12-01
Full Text Available Landslides are usually initiated under complex geological conditions. It is of great significance to find out the optimal combination of predisposing factors and create an accurate landslide susceptibility map based on them. In this paper, the Information Value Model was modified to make the Modified Information Value (MIV Model, and together with GIS (Geographical Information System and AUC (Area Under Receiver Operating Characteristic Curve test, 32 factor combinations were evaluated separately, and factor combination group with members Slope, Lithology, Drainage network, Annual precipitation, Faults, Road and Vegetation was selected as the optimal combination group with an accuracy of 95.0%. Based on this group, a landslide susceptibility zonation map was drawn, where the study area was reclassified into five classes, presenting an accurate description of different levels of landslide susceptibility, with 79.41% and 13.67% of the validating field survey landslides falling in the Very High and High zones, respectively, mainly distributed in the south and southeast of the catchment. It showed that MIV model can tackle the problem of “no data in subclass” well, generate the true information value and show real running trend, which performs well in showing the relationship between predisposing factors and landslide occurrence and can be used for preliminary landslide susceptibility assessment in the study area.
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The 22 March 2014 Oso landslide, Washington, USA
Wartman, Joseph; Montgomery, David R.; Anderson, Scott A.; Keaton, Jeffrey R.; Benoît, Jean; dela Chapelle, John; Gilbert, Robert
2016-01-01
The Oso, Washington, USA, landslide occurred on the morning of Saturday, 22 March 2014 and claimed the lives of 43 people. The landslide began within an 200-m-high hillslope comprised of unconsolidated glacial and previous landslide/colluvial deposits; it continued as a debris avalanche/debris flow that rapidly inundated a neighborhood of 35 single-family residences. An intense three-week rainfall that immediately preceded the event most likely played a role in triggering the landslide; and other factors that likely contributed to destabilization of the landslide mass include alteration of the local groundwater recharge and hydrogeological regime from previous landsliding, weakening and alteration of the landslide mass caused by previous landsliding, and changes in stress distribution resulting from removal and deposition of material from earlier landsliding. Field reconnaissance following the event revealed six distinctive zones and several subzones that are characterized on the basis of geomorphic expression, styles of deformation, geologic materials, and the types, size, and orientation of vegetation. Seismic recording of the landslide indicate that the event was marked by several vibration-generating episodes of mass movement. We hypothesize that the landslide occurred in two stages, with the first being a sequential remobilization of existing slide masses from the most recent (2006) landslide and from an ancient slide that triggered a devastating debris avalanche/debris flow. The second stage involved headward extension into previously unfailed material that occurred in response to unloading and redirection of stresses.
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Accuracy assessment of landslide prediction models
International Nuclear Information System (INIS)
Othman, A N; Mohd, W M N W; Noraini, S
2014-01-01
The increasing population and expansion of settlements over hilly areas has greatly increased the impact of natural disasters such as landslide. Therefore, it is important to developed models which could accurately predict landslide hazard zones. Over the years, various techniques and models have been developed to predict landslide hazard zones. The aim of this paper is to access the accuracy of landslide prediction models developed by the authors. The methodology involved the selection of study area, data acquisition, data processing and model development and also data analysis. The development of these models are based on nine different landslide inducing parameters i.e. slope, land use, lithology, soil properties, geomorphology, flow accumulation, aspect, proximity to river and proximity to road. Rank sum, rating, pairwise comparison and AHP techniques are used to determine the weights for each of the parameters used. Four (4) different models which consider different parameter combinations are developed by the authors. Results obtained are compared to landslide history and accuracies for Model 1, Model 2, Model 3 and Model 4 are 66.7, 66.7%, 60% and 22.9% respectively. From the results, rank sum, rating and pairwise comparison can be useful techniques to predict landslide hazard zones
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Fort, Monique; Braucher, Regis; Bourlès, Didier; Guillou, Valery; Nath Rimal, Lila; Gribenski, Natacha; Cossart, Etienne
2014-05-01
Large catastrophic slope failures have recently retained much attention in the northern dry Himalayas (1). They play a prominent role in the denudation history of active orogens at a wide range of spatial and time scales (2), and they impact durably landforms and process evolution in upstream catchments. Their occurrence mostly results from three different potential triggers: earthquakes, post-glacial debuttressing, and permafrost melting. We focus on two examples of giant rock slope failures that occurred across and north of the Higher Himalaya of Nepal and assess their respective influence on the regional, geomorphic evolution. The Ringmo rockslide (4.5 km3) results from the collapse of a mountain wall (5148 m) cut into palaeozoic dolomites of the Tethysian Himalayas. It caused the damming of the Suli Gad River at the origin of the Phoksumdo Lake (3600 m asl). The presence of glacial till at the very base of the sequence suggests the rockslide event is post-glacial, a field assumption confirmed by cosmogenic dating. Two consistent 36Cl ages of 20,885 ±1675 argue for a single, massive event of paraglacial origin that fits well with the last chronologies available on the Last Glacial Maximum in the Nepal Himalaya. The persistence of the Phoksumdo Lake is due to its dam stability (i.e. high lime content of landslide components) and to low sediment flux from the arid, upper Suli Gad catchment. The Dhampu-Chhoya rock avalanche (about 1 km3, area extent 10 km2) was derived from the northward failure of the Kaiku ridge, uphold by north-dipping, upper crystallines of the Higher Himalaya. It dammed the Kali Gandaki River, with complex interactions with the Late Pleistocene ice tongues derived from the Dhaulagiri (8167 m) and Nilgiris (7061 m) peaks. Both the rock avalanche and glaciers controlled the existence and level of the "Marpha Lake" (lacustrine deposits up to Kagbeni). Again, consistent 10Be ages of 29,680 ± 1015 ka obtained from two large blocks (>1000 m3
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Monsoon Rainfall and Landslides in Nepal
Dahal, R. K.; Hasegawa, S.; Bhandary, N. P.; Yatabe, R.
2009-12-01
A large number of human settlements on the Nepal Himalayas are situated either on old landslide mass or on landslide-prone areas. As a result, a great number of people are affected by large- and small-scale landslides all over the Himalayas especially during monsoon periods. In Nepal, only in the half monsoon period (June 10 to August 15), 70, 50 and 68 people were killed from landslides in 2007, 2008 and 2009, respectively. In this context, this paper highlights monsoon rainfall and their implications in the Nepal Himalaya. In Nepal, monsoon is major source of rainfall in summer and approximately 80% of the annual total rainfall occurs from June to September. The measured values of mean annual precipitation in Nepal range from a low of approximately 250 mm at area north of the Himalaya to many areas exceeding 6,000 mm. The mean annual rainfall varying between 1500 mm and 2500 mm predominate over most of the country. In Nepal, the daily distribution of precipitation during rainy season is also uneven. Sometime 10% of the total annual precipitation can occur in a single day. Similarly, 50% total annual rainfall also can occur within 10 days of monsoon. This type of uneven distribution plays an important role in triggering many landslides in Nepal. When spatial distribution of landslides was evaluated from record of more than 650 landslides, it is found that more landslides events were concentrated at central Nepal in the area of high mean annual rainfall. When monsoon rainfall and landslide relationship was taken into consideration, it was noticed that a considerable number of landslides were triggered in the Himalaya by continuous rainfall of 3 to 90 days. It has been noticed that continuous rainfall of few days (5 days or 7 days or 10 days) are usually responsible for landsliding in the Nepal Himalaya. Monsoon rains usually fall with interruptions of 2-3 days and are generally characterized by low intensity and long duration. Thus, there is a strong role of
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Crozier, M. J.
2018-04-01
Multiple-occurrence regional landslide events (MORLEs) consist of hundreds to thousands of shallow landslides occurring more or less simultaneously within defined areas, ranging from tens to thousands of square kilometres. While MORLEs can be triggered by rainstorms and earthquakes, this paper is confined to those landslide events triggered by rainstorms. Globally, MORLEs occur in a range of geological settings in areas of moderate to steep slopes subject to intense rainstorms. Individual landslides in rainstorm-triggered events are dominantly small, shallow debris and earth flows, and debris and earth slides involving regolith or weathered bedrock. The model used to characterise these events assumes that energy distribution within the event area is represented on the land surface by a cell structure; with maximum energy expenditure within an identifiable core and rapid dissipation concentrically away from the centre. The version of the model presented here has been developed for rainfall-triggered landslide events. It proposes that rainfall intensity can be used to determine different critical landslide response zones within the cell (referred to as core, middle, and periphery zones). These zones are most readily distinguished by two conditions: the proportion of the slope that fails and the particular type of the slope stability factor that assumes dominance in determining specific sites of landslide occurrence. The latter condition means that the power of any slope stability factor to distinguish between stable and unstable sites varies throughout the affected area in accordance with the landslide response zones within the cell; certain factors critical for determining the location of landslide sites in one part of the event area have little influence in other parts of the event area. The implication is that landslide susceptibility maps (and subsequently derived mitigation measures) based on conventional slope stability factors may have only limited validity
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Czech Academy of Sciences Publication Activity Database
Klimeš, Jan
2013-01-01
Roč. 70, č. 2 (2013), s. 913-925 ISSN 1866-6280 Institutional research plan: CEZ:AV0Z30460519 Keywords : landslide inventory * landslide frequency * susceptibility map Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.572, year: 2013
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Directions of the US Geological Survey Landslide Hazards Reduction Program
Wieczorek, G.F.
1993-01-01
The US Geological Survey (USGS) Landslide Hazards Reduction Program includes studies of landslide process and prediction, landslide susceptibility and risk mapping, landslide recurrence and slope evolution, and research application and technology transfer. Studies of landslide processes have been recently conducted in Virginia, Utah, California, Alaska, and Hawaii, Landslide susceptibility maps provide a very important tool for landslide hazard reduction. The effects of engineering-geologic characteristics of rocks, seismic activity, short and long-term climatic change on landslide recurrence are under study. Detailed measurement of movement and deformation has begun on some active landslides. -from Author
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Estimating the empirical probability of submarine landslide occurrence
Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger
2010-01-01
The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.
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Monitoring landslide dynamics using timeseries of UAV imagery
de Jong, S. M.; Van Beek, L. P.
2017-12-01
Landslides are worldwide occurring processes that can have large economic impact and sometimes result in fatalities. Multiple factors are important in landslide processes and can make an area prone to landslide activity. Human factors like drainage and removal of vegetation or land clearing are examples of factors that may cause a landslide. Other environmental factors such as topography and the shear strength of the slope material are more difficult to control. Triggering factors for landslides are typically heavy rainfall events or sometimes by earthquakes or under cutting processes by a river. The collection of data about existing landslides in a given area is important for predicting future landslides in that region. We have setup a monitoring program for landslide using cameras aboard Unmanned Airborne Vehicles. UAV with cameras are able to collect ultra-high resolution images and UAVs can be operated in a very flexible way, they just fit in the back of a car. Here, in this study we used Unmanned Aerial Vehicles to collect a time series of high-resolution images over landslides in France and Australia. The algorithm used to process the UAV images into OrthoMosaics and OrthoDEMs is Structure from Motion (SfM). The process generally results in centimeter precision in the horizontal and vertical direction. Such multi-temporal datasets enable the detection of landslide area, the leading edge slope, temporal patterns and volumetric changes of particular areas of the landslide. We measured and computed surface movement of the landslide using the COSI-Corr image correlation algorithm with ground validation. Our study shows the possibilities of generating accurate Digital Surface Models (DSMs) of landslides using images collected with an Unmanned Aerial Vehicle (UAV). The technique is robust and repeatable such that a substantial time series of datasets can be routinely collected. It is shown that a time-series of UAV images can be used to map landslide movements with
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Landslides in Flanders (Belgium): Where science meets public policy
van den Eeckhaut, M.; Poesen, J.; Vandekerckhove, L.
2009-04-01
Although scientific research on landslides in the Flemish Ardennes (710 km²; Belgium), has been conducted over the last decades, the Flemish Government only took account of slope failure as a soil degradation process after the occurrence of several damaging landslides in the beginning of the 21st century. Here we aim to present the successful collaboration between the Physical and Regional Geography Research Group (FRG; Dept. Earth and Environmental Sciences K.U.Leuven) and the Environment, Nature and Energy Department (LNE; Flemish Government) in landslide management. We will demonstrate how geomorphologists produced practical tools for landslide management which can be directly applied by LNE as well as other local and regional authorities and planners. Since 2004 three projects on landslide inventory mapping and susceptibility assessment in the Flemish Ardennes have been funded by LNE, and a fourth one on landslide susceptibility assessment in remaining hilly regions in Flanders west of Brussels recently started. Together with a steering committee composed of stakeholders, persons from LNE supervise the research carried out by geomorphologists experienced in landslide studies. For the establishment of the landslide inventory map of the Flemish Ardennes we combined the analysis of LIDAR-derived hillshade and contour line maps with detailed field controls. Additional information was collected through interviews with local authorities and inhabitants and from analysis of newspaper articles and technical reports. Then, a statistical model, logistic regression, was applied to produce a high quality classified landslide susceptibility map. The unique part of this collaboration is that all end products are online available at user-friendly websites designed by LNE. The scientific report containing (1) general information on landslides, (2) a description of the study area, (3) an explanation of the materials and methods used, (4) a presentation of the resulting
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Stepwise mitigation of the Macesnik landslide, N Slovenia
Directory of Open Access Journals (Sweden)
M. Mikoš
2005-01-01
Full Text Available The paper gives an overview of the history of evolution and mitigation of the Macesnik landslide in N Slovenia. It was triggered in 1989 above the Solčava village, but it enlarged with time. In 2005, the landslide has been threatening a few residential and farm houses, as well as the panoramic road, and it is only 1000 m away from the Savinja River and the village of Solčava. It is 2500 m long and up to more than 100 m wide with an estimated volume in excess of 2 million m3. Its depth is not constant: on average it is 10 to 15 m deep, but in the area of the toe, which is retained by a rock outcrop, it reaches the depth of 30 m. The unstable mass consists of water-saturated highly-weathered carboniferous formations. The presently active landslide lies within the fossil landslide which is up to 350 m wide and 50 m deep with the total volume estimated at 8 to 10 million m3. Since 2000, the landslide has been investigated by 36 boreholes, and 28 of them were equipped with inclinometer casings, which also serve as piezometers. Surface movements have been monitored geodetically in 20 cross sections. This helped to understand the causes and mechanics of the landslide. Therefore, landslide mitigation works were planned rather to reduce the landslide movement so that the resulting damages could be minimized. The construction of mitigation works was made difficult in the 1990s due to intensive landslide movements that could reach up to 50 cm/day with an average of 25 cm/day. Since 2001, surface drainage works in the form of open surface drains have mainly been completed around the circumference of the landslide as the first phase of the mitigation works and they are regularly maintained. As a final mitigation solution, plans have been made to build a combination of subsurface drainage works in the form of deep drains with retaining works in the form of concrete vertical shafts functioning as deep water wells to drain the landslide, and as dowels to stop
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Schwindt, Daniel; Sandmeier, Christine; Büdel, Christian; Jäger, Daniel; Wilde, Martina; Terhorst, Birgit
2016-04-01
Investigations on landslide activity in the cuesta landscape of Germany, usually characterized by an interbedding of morphologically hard (e.g. sand-/limestones) and soft (clay) sedimentary rocks are relatively sparse. However, spring 2013 has once again revealed a high susceptibility of the slopes in the Franconian and Swabian Alb to mass movements, when enduring rainfalls initiated numerous landslides causing considerable damage to settlements and infrastructure. Many aspects like the spatial distribution of landslides, triggering factors, and process dynamics - especially with view on the reactivation of landslides - require intensive investigations to allow for assessment of the landslide vulnerability and the development of reliable early-warning systems. Aim of the study is to achieve a deeper insight into the triggering factors and the process dynamics of landslides in the cuesta landscape with special regard on landslide proneness of slopes and the potential reactivation of old landslides. A multi-methodological approach was conducted based on geophysical investigations (seismic refraction tomography - SRT, electrical resistivity tomography - ERT), geomorphological mapping, morphometric GIS-based analysis, core soundings and substrate mapping. Study sites are located in the Swabian Alb (southwestern Germany) in the Jurassic escarpment where where Oxfordian marls and limestones superimpose Callovian clays, as well as in the northeastern Franconian Alb, within the escarpment of the so called Rhätolias with with red claystones of the late Norian (Feuerletten formation) below interbedding layers of sand- and claystones of the Rhaetian (Upper Triassic) and Hettangian ( Lower Jurassic). The investigated landslides strongly differ with respect to their age, from young landslides originated in spring 2013 to ancient landslides. Investigations reveal a distinct diversity of landslide types composed of a complex combination of processes. The applied methods allow
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Yen, Hsin-Yi; Lin, Guan-Wei
2017-04-01
Understanding the rainfall condition which triggers mass moment on hillslope is the key to forecast rainfall-induced slope hazards, and the exact time of landslide occurrence is one of the basic information for rainfall statistics. In the study, we focused on large-scale landslides (LSLs) with disturbed area larger than 10 ha and conducted a string of studies including the recognition of landslide-induced ground motions and the analyses of different terms of rainfall thresholds. More than 10 heavy typhoons during the periods of 2005-2014 in Taiwan induced more than hundreds of LSLs and provided the opportunity to characterize the rainfall conditions which trigger LSLs. A total of 101 landslide-induced seismic signals were identified from the records of Taiwan seismic network. These signals exposed the occurrence time of landslide to assess rainfall conditions. Rainfall analyses showed that LSLs occurred when cumulative rainfall exceeded 500 mm. The results of rainfall-threshold analyses revealed that it is difficult to distinct LSLs from small-scale landslides (SSLs) by the I-D and R-D methods, but the I-R method can achieve the discrimination. Besides, an enhanced three-factor threshold considering deep water content was proposed as the rainfall threshold for LSLs.
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Rainstorms as a landslide-triggering factor in Slovenia
Directory of Open Access Journals (Sweden)
Marko Komac
2005-12-01
Full Text Available Rainfall plays an important role in the landslide triggering processes. Analyses of landslide occurrence in the area of Slovenia have shown that areas where intensive rainstorms occure (maximal daily rainfall for the 100 years period, and where the geologicalsettings are favourable, abundance of landslide can be expected. This clearly indicates the spatial and temporal dependence of landslide occurrence upon the intensive rainfall. Regarding the landslide occurrence, the intensity of maximal daily and average annual rainfall for the the 30 years period were analysed. Results have shown that daily rainfall intensity, which significantly influences the triggering of landslides, ranges from 100 to 150 mm, most probably above 130 mm. Despite the vague influence, if any at all,of the average annual rainfall, the threshold above which significant number of landslides occurs is 1000 mm.
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Landslide research in the South Wales coalfield
International Nuclear Information System (INIS)
Bentley, S.P.; Siddle, H.J.
1996-01-01
The areal density of landslides in the coalfield of South Wales is one of the highest in the UK. During the past 100 years landsliding has had considerable impact, causing structural damage and loss of life. Most of the landslides were initiated under periglacial conditions but many became reactivated due to the activities of man, particularly, during the late 19th century when widespread urban and industrial development commenced in the Welsh valleys. A number of the area's larger landslides are first-time slides which occurred during the past 100 years. This paper sets out to chart the history of landslide research in the coalfield, which began through work by mining engineers. 47 refs., 6 figs., 2 tabs
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Investigating landslides caused by earthquakes - A historical review
Keefer, D.K.
2002-01-01
Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated with earthquake-induced landslides. This paper traces the historical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquake are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession of post-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing "retrospective" analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, synthesis of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still
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Investigating Landslides Caused by Earthquakes A Historical Review
Keefer, David K.
Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated withearthquake-induced landslides. This paper traces thehistorical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquakes are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession ofpost-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing ``retrospective'' analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, syntheses of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still
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Cross-slope Movement Patterns in Landslides
Petley, D.; Murphy, W.; Bulmer, M. H.; Keefer, D.
2002-12-01
There is growing evidence that there is a significant element of cross-slope movement in many large landslide systems. These movements may result in changing states of stress between landslide blocks that can establish complex displacement patterns. Such motions, which are not considered in traditional two-dimensional limit-equilibrium analyses, are important in the investigation of a variety of landslide types, such as those triggered by earthquakes. In addition, these movements may introduce considerable errors into the interpretation of strain patterns as derived from InSAR studies. Finally, even traditional interpretation techniques may lead to the amount of total displacement being underestimated. These observations suggest that a three dimensional form of analysis may be more appropriate for large landslide complexes. The significance of such cross-slope movements are being investigated using a detailed investigation of the Lishan landslide complex in Central Taiwan. This landslide system, which was reactivated in 1990 related to the construction of a hotel. The total recorded movements have been approximately 1.5 m over an area of sliding that is estimated to be 450 m wide and 200 m long. Extensive damage has been caused to roads and buildings within the town. Remediation work has resulted largely in the stabilization of the landslide complex. Detailed geomorphological mapping has revealed that the landslide complex is composed of two main components. The first, immediately upslope of the hotel construction site, is a relatively shallow earthflow. The second, which has formed a large headscarp upslope from the main road in the centre of the town, is a deeper translational slide. Both appear to have been reactivations of previous failures. While the displacement patterns of the earthflow indicate a relatively simple downslope movement, the vectors derived from kinematic analysis of surface features have indicated that the movement of the deeper
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Landslide Hazard Mapping in Rwanda Using Logistic Regression
Piller, A.; Anderson, E.; Ballard, H.
2015-12-01
Landslides in the United States cause more than $1 billion in damages and 50 deaths per year (USGS 2014). Globally, figures are much more grave, yet monitoring, mapping and forecasting of these hazards are less than adequate. Seventy-five percent of the population of Rwanda earns a living from farming, mostly subsistence. Loss of farmland, housing, or life, to landslides is a very real hazard. Landslides in Rwanda have an impact at the economic, social, and environmental level. In a developing nation that faces challenges in tracking, cataloging, and predicting the numerous landslides that occur each year, satellite imagery and spatial analysis allow for remote study. We have focused on the development of a landslide inventory and a statistical methodology for assessing landslide hazards. Using logistic regression on approximately 30 test variables (i.e. slope, soil type, land cover, etc.) and a sample of over 200 landslides, we determine which variables are statistically most relevant to landslide occurrence in Rwanda. A preliminary predictive hazard map for Rwanda has been produced, using the variables selected from the logistic regression analysis.
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Radbruch-Hall, D. H.; Varnes, D.J.
1976-01-01
Landslides can cause seismic disturbances; landslides can also result from seismic disturbances, and earthquake-induced slides have caused loss of life in many countries. Slides can cause disastrous flooding, particularly when landslide dams across streams are breached, and flooding may trigger slides. Slope movement in general is a major process of the geologic environment that places constraints on engineering development. In order to understand and foresee both the causes and effects of slope movement, studies must be made on a regional scale, at individual sites, and in the laboratory. Areal studies - some embracing entire countries - have shown that certain geologic conditions on slopes facilitate landsliding; these conditions include intensely sheared rocks; poorly consolidated, fine-grained clastic rocks; hard fractured rocks underlain by less resistant rocks; or loose accumulations of fine-grained surface debris. Field investigations as well as mathematical- and physical-model studies are increasing our understanding of the mechanism of slope movement in fractured rock, and assist in arriving at practical solutions to landslide problems related to all kinds of land development for human use. Progressive failure of slopes has been studied in both soil and rock mechanics. New procedures have been developed to evaluate earthquake response of embankments and slopes. The finite element method of analysis is being extensively used in the calculation of slope stability in rock broken by joints, faults, and other discontinuities. ?? 1976 International Association of Engineering Geology.
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Paleo-hydraulic Reconstructions of Topographically Inverted River Deposits on Earth and Mars
Hayden, A.; Lamb, M. P.; Fischer, W. W.; Ewing, R. C.; McElroy, B. J.
2015-12-01
River deposits are one of the keys to understanding the history of flowing water and sediment on Earth and Mars. Deposits of some ancient Martian rivers have been topographically inverted resulting in sinuous ridges visible from orbit. However, it is unclear what aspects of the fluvial deposits these ridges represent, so reconstructing paleo-hydraulics from ridge geometry is complicated. Most workers have assumed that ridges represent casts of paleo-river channels, such that ridge widths and slopes, for example, can be proxies for river widths and slopes at some instant in time. Alternatively, ridges might reflect differential erosion of extensive channel bodies, and therefore preserve a rich record of channel conditions and paleoenvironment over time. To explore these hypotheses, we examined well exposed inverted river deposits in the Jurassic Morrison and Early Cretaceous Cedar Mountain Formations across the San Rafael Swell of central Utah. We mapped features on foot and by UAV, measured stratigraphic sections and sedimentary structures to constrain deposit architecture and river paleo-hydraulics, and used field observations and drainage network analyses to constrain recent erosion. Our work partly confirms earlier work in that the local trend of the ridge axis generally parallels paleo-flow indicators. However, ridge relief is much greater than reconstructed channel depths, and ridge widths vary from zero to several times the reconstructed channel width. Ridges instead appear to record a rich history of channel lateral migration, floodplain deposition, and soil development over significant time. The ridge network is disjointed owing to active modern fluvial incision and scarp retreat. Our results suggest that ridge geometry alone contains limited quantitative information about paleo-rivers, and that stratigraphic sections and observations of sedimentary structures within ridge-forming deposits are necessary to constrain ancient river systems on Mars.
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Van Den Eeckhaut, Miet; Hervás, Javier
2012-02-01
A landslide inventory is the most important information source for quantitative zoning of landslide susceptibility, hazard and risk. It should give insight into the location, date, type, size, activity and causal factors of landslides as well as resultant damage. In Europe, many countries have created or are creating national and/or regional landslide databases (LDBs). Yet little is known on their contents, completeness, format, structure, language use and accessibility, and hence on their ability to perform national or transnational landslide zoning. Therefore, this study presents a detailed analysis of existing national LDBs in the EU member states, EU official candidate and potential candidate countries, and EFTA countries, and their possible use for landslide zoning. These national LDBs were compared with a subset of 22 regional databases. Twenty-two out of 37 contacted European countries currently have national LDBs, and six other countries have only regional LDBs. In total, the national LDBs contain 633,696 landslides, of which 485,004 are located in Italy, while Austria, the Czech Republic, France, Norway, Poland, Slovakia, and the UK also have > 10,000 landslides in their LDBs. National LDBs are generally created in the official language of each country and 58% of them contain other natural hazards (e.g. floods and sinkholes). About 68% of the LDBs contain less than 50% of all landslides in each country, but a positive observation is that 60% of the LDBs are updated at least once a year or after a major event. Most landslide locations are collected with traditional methods such as field surveys, aerial photo interpretation and analysis of historical records. Currently, integration of landslide information from different national LDBs is hampered because of differences in language and classification systems for landslide type and activity. Other problems are that currently only half of the national LDBs have a direct link between spatial and alphanumeric
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Landslides and engineering geology of the Seattle, Washington, area
Baum, Rex L.; Godt, Jonathan W.; Highland, Lynn M.
2008-01-01
This volume brings together case studies and summary papers describing the application of state-of-the-art engineering geologic methods to landslide hazard analysis for the Seattle, Washington, area. An introductory chapter provides a thorough description of the Quaternary and bedrock geology of Seattle. Nine additional chapters review the history of landslide mapping in Seattle, present case studies of individual landslides, describe the results of spatial assessments of landslide hazard, discuss hydrologic controls on landsliding, and outline an early warning system for rainfall-induced landslides.
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Investigating Earthquake-induced LandslidesÂa Historical Review
Keefer, D. K.; Geological Survey, Us; Park, Menlo; Usa, Ca
Although earthquake-induced landslides have been described in documents for more than 3700 years, accounts from earthquakes before the late eighteenth century are incomplete concerning landslide numbers and vague concerning landslide character- istics. They are thus typically misleading concerning the true abundance of landslides and range of landslide characteristics. Beginning with studies of the 1783 Calabria, Italy earthquake, more complete and precise data concerning the occurrence of land- slides in earthquakes have become available. The historical development of knowl- edge concerning landslides triggered by earthquakes can be divided into several peri- ods. The first period, from 1783 until the first application of aerial photography, was characterized by ground-based studies of earthquake effects, typically carried out by formal scientific commissions. These formal studies typically identified a large, but not necessarily comprehensive, sampling of localities where landslides had occurred. In some, but not all cases, landslide characteristics were also described in enough de- tail that the general range of landslide characteristics could begin to be determined. More recently, some nineteenth to mid-twentieth century earthquakes have been stud- ied using retrospective analyses, in which the landslide occurrences associated with the event are inferred years to decades later, using contemporary accounts, mapping from aerial photographs, statistical studies, and (or) geotechnical analyses. The first use of aerial photographs to map earthquake effects immediately after the event prob- ably occurred in 1948. Since that time, the use of aerial photography has greatly facil- itated the compilation of post-earthquake landslide inventories, although because of the limitations of aerial photography, ground-based field studies continue to be cru- cial in preparing accurate and comprehensive landslide maps. Beginning with a small California earthquake in 1957
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Modelling the Probability of Landslides Impacting Road Networks
Taylor, F. E.; Malamud, B. D.
2012-04-01
During a landslide triggering event, the threat of landslides blocking roads poses a risk to logistics, rescue efforts and communities dependant on those road networks. Here we present preliminary results of a stochastic model we have developed to evaluate the probability of landslides intersecting a simple road network during a landslide triggering event and apply simple network indices to measure the state of the road network in the affected region. A 4000 x 4000 cell array with a 5 m x 5 m resolution was used, with a pre-defined simple road network laid onto it, and landslides 'randomly' dropped onto it. Landslide areas (AL) were randomly selected from a three-parameter inverse gamma probability density function, consisting of a power-law decay of about -2.4 for medium and large values of AL and an exponential rollover for small values of AL; the rollover (maximum probability) occurs at about AL = 400 m2 This statistical distribution was chosen based on three substantially complete triggered landslide inventories recorded in existing literature. The number of landslide areas (NL) selected for each triggered event iteration was chosen to have an average density of 1 landslide km-2, i.e. NL = 400 landslide areas chosen randomly for each iteration, and was based on several existing triggered landslide event inventories. A simple road network was chosen, in a 'T' shape configuration, with one road 1 x 4000 cells (5 m x 20 km) in a 'T' formation with another road 1 x 2000 cells (5 m x 10 km). The landslide areas were then randomly 'dropped' over the road array and indices such as the location, size (ABL) and number of road blockages (NBL) recorded. This process was performed 500 times (iterations) in a Monte-Carlo type simulation. Initial results show that for a landslide triggering event with 400 landslides over a 400 km2 region, the number of road blocks per iteration, NBL,ranges from 0 to 7. The average blockage area for the 500 iterations (A¯ BL) is about 3000 m
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Integration of landslide susceptibility products in the environmental plans
Fiorucci, Federica; Reichenbach, Paola; Rossi, Mauro; Cardinali, Mauro; Guzzetti, Fausto
2015-04-01
Landslides are one of the most destructive natural hazard that causes damages to urban area worldwide. The knowledge of where a landslide could occur is essential for the strategic management of the territory and for a good urban planning . In this contest landslide susceptibility zoning (LSZ) is crucial to provide information on the degree to which an area can be affected by future slope movements. Despite landslide susceptibility maps have been prepared extensively during the last decades, there are few examples of application is in the environmental plans (EP). In this work we present a proposal for the integration of the landslide inventory map with the following landslide susceptibility products: (i) landslide susceptibility zonation , (ii) the associated error map and (iii) the susceptibility uncertainty map. Moreover we proposed to incorporate detailed morphological studies for the evaluation of landslide risk associated to local parceling plan. The integration of all this information is crucial for the management of landslide risk in urban expansions forecasts. Municipality, province and regional administration are often not able to support the costs of landslide risk evaluation for extensive areas but should concentrate their financial resources to specific hazardous and unsafe situations defined by the result of the integration of landslide susceptibility products. Zonation and detail morphological analysis should be performed taking into account the existing laws and regulations, and could become a starting point to discuss new regulations for the landslide risk management.
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Forecasting giant, catastrophic slope collapse: lessons from Vajont, Northern Italy
Kilburn, Christopher R. J.; Petley, David N.
2003-08-01
Rapid, giant landslides, or sturzstroms, are among the most powerful natural hazards on Earth. They have minimum volumes of ˜10 6-10 7 m 3 and, normally preceded by prolonged intervals of accelerating creep, are produced by catastrophic and deep-seated slope collapse (loads ˜1-10 MPa). Conventional analyses attribute rapid collapse to unusual mechanisms, such as the vaporization of ground water during sliding. Here, catastrophic collapse is related to self-accelerating rock fracture, common in crustal rocks at loads ˜1-10 MPa and readily catalysed by circulating fluids. Fracturing produces an abrupt drop in resisting stress. Measured stress drops in crustal rock account for minimum sturzstrom volumes and rapid collapse accelerations. Fracturing also provides a physical basis for quantitatively forecasting catastrophic slope failure.
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Landslide susceptibility mapping using a neuro-fuzzy
Lee, S.; Choi, J.; Oh, H.
2009-12-01
This paper develops and applied an adaptive neuro-fuzzy inference system (ANFIS) based on a geographic information system (GIS) environment using landslide-related factors and location for landslide susceptibility mapping. A neuro-fuzzy system is based on a fuzzy system that is trained by a learning algorithm derived from the neural network theory. The learning procedure operates on local information, and causes only local modifications in the underlying fuzzy system. The study area, Boun, suffered much damage following heavy rain in 1998 and was selected as a suitable site for the evaluation of the frequency and distribution of landslides. Boun is located in the central part of Korea. Landslide-related factors such as slope, soil texture, wood type, lithology, and density of lineament were extracted from topographic, soil, forest, and lineament maps. Landslide locations were identified from interpretation of aerial photographs and field surveys. Landslide-susceptible areas were analyzed by the ANFIS method and mapped using occurrence factors. In particular, we applied various membership functions (MFs) and analysis results were verified using the landslide location data. The predictive maps using triangular, trapezoidal, and polynomial MFs were the best individual MFs for modeling landslide susceptibility maps (84.96% accuracy), proving that ANFIS could be very effective in modeling landslide susceptibility mapping. Various MFs were used in this study, and after verification, the difference in accuracy according to the MFs was small, between 84.81% and 84.96%. The difference was just 0.15% and therefore the choice of MFs was not important in the study. Also, compared with the likelihood ratio model, which showed 84.94%, the accuracy was similar. Thus, the ANFIS could be applied to other study areas with different data and other study methods such as cross-validation. The developed ANFIS learns the if-then rules between landslide-related factors and landslide
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Landslide hazard assessment in the Collazzone area, Umbria, Central Italy
Directory of Open Access Journals (Sweden)
F. Guzzetti
2006-01-01
Full Text Available We present the results of the application of a recently proposed model to determine landslide hazard. The model predicts where landslides will occur, how frequently they will occur, and how large they will be in a given area. For the Collazzone area, in the central Italian Apennines, we prepared a multi-temporal inventory map through the interpretation of multiple sets of aerial photographs taken between 1941 and 1997 and field surveys conducted in the period between 1998 and 2004. We then partitioned the 79 square kilometres study area into 894 slope units, and obtained the probability of spatial occurrence of landslides by discriminant analysis of thematic variables, including morphology, lithology, structure and land use. For each slope unit, we computed the expected landslide recurrence by dividing the total number of landslide events inventoried in the terrain unit by the time span of the investigated period. Assuming landslide recurrence was constant, and adopting a Poisson probability model, we determined the exceedance probability of having one or more landslides in each slope unit, for different periods. We obtained the probability of landslide size, a proxy for landslide magnitude, by analysing the frequency-area statistics of landslides, obtained from the multi-temporal inventory map. Lastly, assuming independence, we determined landslide hazard for each slope unit as the joint probability of landslide size, of landslide temporal occurrence, and of landslide spatial occurrence.
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Roulleau, Louise; Bétard, François; Carlier, Benoît; Lissak, Candide; Fort, Monique
2016-04-01
Landslides are common natural hazards in the Southern French Alps, where they may affect human lives and cause severe damages to infrastructures. As a part of the SAMCO research project dedicated to risk evaluation in mountain areas, this study focuses on the Guil river catchment (317 km2), Queyras, to assess landslide hazard poorly studied until now. In that area, landslides are mainly occasional, low amplitude phenomena, with limited direct impacts when compared to other hazards such as floods or snow avalanches. However, when interacting with floods during extreme rainfall events, landslides may have indirect consequences of greater importance because of strong hillslope-channel connectivity along the Guil River and its tributaries (i.e. positive feedbacks). This specific morphodynamic functioning reinforces the need to have a better understanding of landslide hazards and their spatial distribution at the catchment scale to prevent local population from disasters with multi-hazard origin. The aim of this study is to produce a landslide susceptibility mapping at 1:50 000 scale as a first step towards global estimation of landslide hazard and risk. The three main methodologies used for assessing landslide susceptibility are qualitative (i.e. expert opinion), deterministic (i.e. physics-based models) and statistical methods (i.e. probabilistic models). Due to the rapid development of geographical information systems (GIS) during the last two decades, statistical methods are today widely used because they offer a greater objectivity and reproducibility at large scales. Among them, multivariate analyses are considered as the most robust techniques, especially the logistic regression method commonly used in landslide susceptibility mapping. However, this method like others is strongly dependent on the accuracy of the input data to avoid significant errors in the final results. In particular, a complete and accurate landslide inventory is required before the modelling
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Schwab, Marco; Rieke-Zapp, Dirk; Schneider, Heinz; Liniger, Markus; Schlunegger, Fritz
2008-05-01
This study explores the effects of hillslope mass failure on the sediment flux in the Waldemme drainage basin, Central Swiss Alps, over decadal time scales. This area is characterized by abundant landslides affecting principally flysch units and is therefore an important sediment source. The analysis concentrates on the Schimbrig landslide that potentially contributes up to 15% to the sediment budget of the Waldemme drainage basin. Volumetric changes are quantified using high-resolution elevation models that were extracted using digital photogrammetric techniques. Sediment discharge data were used to constrain the significance of the landslide for sediment flux in the channel network. The temporal extent of the photogrammetric analysis ranges from 1962 to 1998, including an earth slide event in 1994. The analyses reveal that during periods of low slip rates of the landslide, nearly all of the displaced sediments were eroded and supplied to the channel network. In contrast, during active periods, only a fraction of the displaced landslide mass was exported to the trunk stream. Interestingly, the 1994 earth slide event did not disturb the long-term sediment discharge pattern of the channel network, nor did it influence the sediment flux at a weekly scale. However, suspended sediment pulses correlate with higher-than-average precipitation events. This was especially the case in August 2005 when a storm event (> 100 years return period) triggered several debris flows and earth flows in the whole drainage basin and in the Schimbrig area. This storm did not result in a significant increase in the slip rates of the entire landslide's main body. It is therefore proposed that debris flows and earth flows perform the connectivity between hillslope processes (e.g. landsliding) and the trunk stream during and between phases of landslide activity in this particular setting.
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WU, Chunhung
2015-04-01
The research built the original logistic regression landslide susceptibility model (abbreviated as or-LRLSM) and landslide ratio-based ogistic regression landslide susceptibility model (abbreviated as lr-LRLSM), compared the performance and explained the error source of two models. The research assumes that the performance of the logistic regression model can be better if the distribution of landslide ratio and weighted value of each variable is similar. Landslide ratio is the ratio of landslide area to total area in the specific area and an useful index to evaluate the seriousness of landslide disaster in Taiwan. The research adopted the landside inventory induced by 2009 Typhoon Morakot in the Chishan watershed, which was the most serious disaster event in the last decade, in Taiwan. The research adopted the 20 m grid as the basic unit in building the LRLSM, and six variables, including elevation, slope, aspect, geological formation, accumulated rainfall, and bank erosion, were included in the two models. The six variables were divided as continuous variables, including elevation, slope, and accumulated rainfall, and categorical variables, including aspect, geological formation and bank erosion in building the or-LRLSM, while all variables, which were classified based on landslide ratio, were categorical variables in building the lr-LRLSM. Because the count of whole basic unit in the Chishan watershed was too much to calculate by using commercial software, the research took random sampling instead of the whole basic units. The research adopted equal proportions of landslide unit and not landslide unit in logistic regression analysis. The research took 10 times random sampling and selected the group with the best Cox & Snell R2 value and Nagelkerker R2 value as the database for the following analysis. Based on the best result from 10 random sampling groups, the or-LRLSM (lr-LRLSM) is significant at the 1% level with Cox & Snell R2 = 0.190 (0.196) and Nagelkerke R2
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Mechanisms of Forest Restoration in Landslide Treatment Areas
Directory of Open Access Journals (Sweden)
Yi-Chang Chen
2014-09-01
Full Text Available Reforestation after a landslide facilitates competition between herbaceous plants and arborous plants. Tangible variations in grassland areas in regions susceptible to landslides can only be found within collections of trees. A landslide area in the Sule Watershed was investigated. Relative illuminance results reveal that the Rhodes grass (Chloris gayana Kunth biomass in this landslide area increases with relative illuminance. A comparison of regions with tree islands indicates that the size of the grassland areas decreased and the number of tree islands increased during 2005–2010. Furthermore, a germination experiment in a soil-seed bank indicates that more woody plant species exist around the tree island than in other areas in the landslide region. Trees in a tree island change the micro-climate of the landslide region, and they gather as many nutrients and as much moisture as possible, enabling vegetation to expand around the tree island. Additionally, the area with Rhodes grass and its biomass declined annually in the tree island region. Investigation results show that tree islands and soil-seed banks are suited to reforestation in landslide regions. The pioneering research will assist regional landslide management in Taiwan.
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An illustrated landslide handbook for developing nations
Highland, Lynn M.; Bobrowsky, Peter
2008-01-01
As landslides continue to be a hazard that account for large numbers of human and animal casualties, property loss, and infrastructure damage, as well as impacts on the natural environment, it is incumbent on developed nations that resources be allocated to educate affected populations in less developed nations, and provide them with tools to effectively manage this hazard. Given that the engineering, planning and zoning, and mitigation techniques for landslide hazard reduction are more accessible to developed nations, it is crucial that such landslide hazard management tools be communicated to less developed nations in a language that is not overly technical, and provides information on basic scientific explanations on where, why and how landslides occur. The experiences of the United States, Canada, and many other nations demonstrate that, landslide science education, and techniques for reducing damaging landslide impacts may be presented in a manner that can be understood by the layperson. There are various methods through which this may be accomplished–community-level education, technology transfer, and active one-on-one outreach to national and local governments, and non-governmental organizations (NGOs), who disseminate information throughout the general population. The population at large can also benefit from the dissemination of landslide information directly to individual community members. The United States Geological Survey and the Geological Survey of Canada have just published and will distribute a universal landslide handbook that can be easily made available to emergency managers, local governments, and individuals. The handbook, “The Landslide Handbook: A Guide to Understanding Landslides” is initially published as U.S. Geological Survey Circular 1325, in English, available in print, and accessible on the internet. It is liberally illustrated with schematics and photographs, and provides the means for a basic understanding of landslides, with
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Comparison and Evolution of Extreme Rainfall-Induced Landslides in Taiwan
Directory of Open Access Journals (Sweden)
Chunhung WU
2017-11-01
Full Text Available This study analyzed the characteristics of, and locations prone to, extreme rainfall-induced landslides in three watersheds in Taiwan, as well as the long-term evolution of landslides in the Laonong River watershed (LRW, based on multiannual landslide inventories during 2003–2014. Extreme rainfall-induced landslides were centralized beside sinuous or meandering reaches, especially those with large sediment deposition. Landslide-prone strata during extreme rainfall events were sandstone and siltstone. Large-scale landslides were likely to occur when the maximum 6-h accumulated rainfall exceeded 420 mm. All of the large-scale landslides induced by short-duration and high-intensity rainfall developed from historical small-scale landslides beside the sinuous or meandering reaches or in the source area of rivers. However, most of the large-scale landslides induced by long-duration and high-intensity rainfall were new but were still located beside sinuous or meandering reaches or near the source. The frequency density of landslides under long-duration and high-intensity rainfall was larger by one order than those under short-duration rainfall, and the β values in the landslide frequency density-area analysis ranged from 1.22 to 1.348. The number of downslope landslides was three times larger than those of midslope and upslope landslides. The extreme rainfall-induced landslides occurred in the erosion gullies upstream of the watersheds, whereas those beside rivers were downstream. Analysis of the long-term evolution of landslides in the LRW showed that the geological setting, sinuousness of reaches, and sediment yield volume determined their location and evolution. Small-scale landslides constituted 71.9–96.2% of the total cases from 2003 to 2014, and were more easily induced after Typhoon Morakot (2009. The frequency density of landslides after Morakot was greater by one order than before, with 61% to 68% of total landslides located in the
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Landslides in the area of the Jastrzebie town protective pillar
Energy Technology Data Exchange (ETDEWEB)
Rybicki, S
1986-01-01
Analyzes 76 landslides in the area of the safety pillar of Jastrzebie in the Rybnik coal region. Of 76 landslides 60% fell on natural slopes with an angle of 25-50 degrees, 22% on natural slopes with a 5-25 degree angle, 10% on man-made cuts and 8% on embankments. About 78% of the landslides was associated with water bearing layers. Of the 76 landslides 32 were situated in the safety pillar and 44 close to the pillar. Thirty-three landslides were closely associated with underground mining: 30 landslides were caused by longwall mining (landslide position was related to working face position), a further 3 were associated with mining in general. Statistical data on landslides associated with underground coal mining are analyzed: landslide area, angle of slope inclination, height, landslide range, water conditions, types of soils, types of mining areas classified according to effects of mining damage. 8 refs.
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Nicolas, Bollot; Guillaume, Pierre; Gilles, Grandjean
2014-05-01
Key words : landslide, Champagne vineyards , geomorphology, geophysical data, superficial structure The Champagne region is strongly impacted by landslides. Usually inactive, these landslides suffer from partial reactivations leading to important damages, especially when they occur in the vineyards. In the Marne valley, and particularly in the center of Champagne vineyards area (Reuil), the Jacotines site is representative of such landslides since it presents typical surface characteristics widely observed in the region. However, its size, and especially its internal structure, can't be deduced from the surface analysis only. The aim of this work is to combine surface patterns analysis, geophysical data and borehole data to produce an interpretative model of the landslide. Preliminary geomorphological cartography was used for determining the influence of the landslide. From this information, geophysical investigations were carried out to image the internal structure of the landslide. Geophysical data fusion (combination of seismic and geoelectrical tomograms) was used to estimate the mechanical behavior and the fissuring pattern of the slope. Three transverse and longitudinal tomograms were used to define an heterogeneous area between 20 and 50 meters depth and a weathered zone from 0 to 10-20 meters depth. A 60 meters depth borehole on the main transverse tomogram found the shear plane and clarified the structure of the heterogeneous area as well as the uppermost weathered layer composed by debris flows resulting from partial reactivations processes.
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Paleo-oncology: the role of ancient remains in the study of cancer.
Halperin, Edward C
2004-01-01
Paleo-oncology is the study of carcinomas and sarcomas in ancient human populations and their hominid precursors. These populations are informative concerning the possible influences on cancer of morphologic and functional evolution, diet, lifestyle, and other environmental factors. The prevalence of cancer in ancient populations might have differed from that in modern humans, because of substantial differences in tobacco and alcohol use, diet, life expectancy, and the availability of treatment. The available physical data concerning cancer in antiquity includes evidence of its existence in animal fossils and ancient humans and their precursors. The difficulties of paleo-oncologic research include a limited soft tissue record. In evaluating cancer in ancient remains, one must also deal with the problem of pseudopathology: whether an observed tissue change is all antemortem pathologic lesion or a postmortem artifact. Future archeological discoveries and the application of improved diagnostic techniques may enable paleo-oncology to make further contributions to our understanding of cancer.
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Dendrogeomorphology in landslide analysis: State of art
Energy Technology Data Exchange (ETDEWEB)
Margottini, C [ENEA, Casaccia (Italy). Area Energia Ambiente e Salute; Fantucci, R
1994-01-01
This article summarizes the uses of dendrogeomorphological techniques in landslide analysis. It shows how to study different landslides events through the analysis of living trees. Living trees record any slope inclination variation as if they were natural inclinometers moreover they can be used to date landslide and their stabilization process with time.
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On the occurrence of fatal landslides in 2008
Petley, D.
2009-04-01
This paper represents the latest in an annual review of fatal landslide events worldwide, based upon the Durham Fatal Landslide Database. Landslide events were inevitably dominated by the occurrence of the 12th May Wenchuan Earthquake in Sichuan Province of China, which triggered very extensive landsliding. Whilst it will be very difficult to estimate the true impact of this event in terms of landslides, the Chinese authorities estimate that about 29,000 people were killed by landslides, with several thousand more losing their lives whilst trapped in rubble due to the inability of rescuers to pass through landslide affected areas. Considerable work is needed to understand the reasons for the intensity of the landslide processes. Elsewhere the number of fatal landslides recorded totalled 405 worldwide. These caused 3526 fatalities, giving a total for the year of about 32,526 people. To put this into context, according to the CRED EM-DAT database the recorded number of fatalities from volcanic eruptions in the period 2000 to 2008 inclusive is 221! The distribution of fatal landslides followed the familiar patterns observed in previous years, with distinct clusters in Central China, along the southern edge of the Himalayas, in the Caribbean, in Central America, western S. America, along the western edge of the Philippine Sea plate and in Indonesia, plus a scattering elsewhere. The temporal distribution shows strong seasonality, with the peak occurring during the northern hemisphere summer. Unusually however, the peak month was September (usually it is in July), and there were large numbers of landslide events right through to November. The November landslide clusters occurred in SE. Asia and in Central / S. America, reflecting very heavy rains in these regions at that time. The reasons for this are not clear at present, although may be linked to weakening La Nina conditions that have prevailed through much of the year. An analysis is made of the relationship between
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Can, Eray
2014-04-01
Landslides are natural phenomena in the same class of natural disasters as earthquakes, floods, hurricanes, erosion, and volcanic eruptions that adversely affect human lives and property. Owing to their widespread occurrence, landslides are easily visible and able to be partially understood by people witnessing them. Nevertheless, to comprehend the detail of their formation and determine their potential, it is necessary to undertake geodetic, geological, and geophysical measurements in regions prone to landslides. By analyzing these measurements, it is possible to better ascertain those regions predisposed to landslides and thus provide the means to prevent loss of life and property. The city of Zonguldak, situated in the Western Black Sea region of Turkey, has a high occurrence of landslides owing to its harsh topography with rugged and steep slopes and rainfall in almost every season. Furthermore, the diurnal temperature ranging up to 10 °C in all seasons, especially in winter, plays a crucial role in rock disintegration in this region. Other factors damage ground composition and trigger landslides, such as underground mining operations, road construction that collapses rocky hills using explosives, and excavation works in steep terrain for building construction. This study gives a detailed account of the causes and adverse effects of landslides and their parameters through examples of landslide occurrences in the region, together with the results and analyses of two periods of geodetic measurements conducted on the Zonguldak-Ereğli Highway in Ilıksu district.
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Assessing Landslide Hazard Using Artificial Neural Network
DEFF Research Database (Denmark)
Farrokhzad, Farzad; Choobbasti, Asskar Janalizadeh; Barari, Amin
2011-01-01
failure" which is main concentration of the current research and "liquefaction failure". Shear failures along shear planes occur when the shear stress along the sliding surfaces exceed the effective shear strength. These slides have been referred to as landslide. An expert system based on artificial...... and factor of safety. It can be stated that the trained neural networks are capable of predicting the stability of slopes and safety factor of landslide hazard in study area with an acceptable level of confidence. Landslide hazard analysis and mapping can provide useful information for catastrophic loss...... reduction, and assist in the development of guidelines for sustainable land use planning. The analysis is used to identify the factors that are related to landslides and to predict the landslide hazard in the future based on such a relationship....
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Case Histories of Landslide Impact: A Database-driven Approach
Klose, Martin; Damm, Bodo
2015-04-01
Fundamental understanding of landslide risk requires in-depth knowledge of how landslides have impacted society in the past (e.g., Corominas et al., 2014). A key to obtain insights into the evolution of landslide risk at single facilities of critical infrastructures are case histories of landslide impact. The purpose of such historical analyses is to inform about the site-specific interactions between landslides and land-use activity. Case histories support correlating landslide events and associated damages with multiple control variables of landslide risk, including (i) previous construction works, (ii) hazard awareness, (iii) the type of structure or its material properties, and (iv) measures of post-disaster mitigation. It is a key advantage of case histories to provide an overview of the changes in the exposure and vulnerability of infrastructures over time. Their application helps to learn more about changing patterns in risk culture and the effectiveness of repair or prevention measures (e.g., Klose et al., 2014). Case histories of landslide impact are developed on the basis of information extracted from landslide databases. The use of path diagrams and illustrated flowcharts as data modeling techniques is aimed at structuring, condensing, and visualizing complex historical data sets on landslide activity and land-use. Much of the scientific potential of case histories simply depends on the quality of available database information. Landslide databases relying on a bottom-up approach characterized by targeted local data specification are optimally suited for historical impact analyses. Combined with systematic retrieval, extraction, and integration of data from multiple sources, landslide databases constitute a valuable tool for developing case histories that enable to open a whole new window on the study of landslide impacts (e.g., Damm and Klose, 2014). The present contribution introduces such a case history for a well-known landslide site at a heavily
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Landslides in the western Columbia Gorge, Skamania County, Washington
Pierson, Thomas C.; Evarts, Russell C.; Bard, Joseph A.
2016-11-04
SummaryRecent light detection and ranging (lidar) imagery has allowed us to identify and map a large number of previously unrecognized landslides, or slides, in heavily forested terrain in the western Columbia Gorge, Skamania County, Washington, and it has revealed that the few previously recognized areas of instability are actually composites of multiple smaller landslides. The high resolution of the imagery further reveals that landslides in the map area have complex movement histories and span a wide range of relative ages. Movement histories are inferred from relative landslide locations and crosscutting relations of surface features. Estimated age ranges are based on (1) limited absolute dating; (2) relative fineness of landscape surface textures, calibrated by comparison with surfaces of currently active and dated landslides as interpreted from interferometric synthetic aperture radar (InSAR), global positioning system (GPS), and historical records; (3) sharpness and steepness of larger-scale surface morphologic features, calibrated by comparison with similar dated features in other regions; (4) degree of surface erosion; and (5) evidence of erosion or deposition by late Pleistocene (15–22 ka) Missoula floods at or below 200 m altitude. The relative age categories are recent (0 to ~1,000 years old), intermediate-age (~1,000 to ~15,000 years old), and old (>~15,000 years old). Within the 221.5 km2 map area, we identified 215 discrete landslides, covering 140.9 km2 (64 percent of the map area). At least 12 of the recent landslides are currently moving or have moved within the last two decades. Mapping for this study expanded the area of previously recognized unstable terrain by 56 percent. Landslide geometries suggest that more than half (62 percent) of these slope failures are translational landslides or composite landslides with translational elements, with failure occurring along gently sloping bedding planes in zones of deeply weathered, locally clay rich
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Landslide disaster avoidance: learning from Leyte
Davies, T. R.
2006-12-01
On 17 February 2006 a gigantic rockslide triggered a debris avalanche that overran the barangay Guinsaugon, St. Bernard in Southern Leyte Province, Philippines, burying 154 victims, with 990 missing including 246 school children. Even with satellite imagery, GIS-based landslide susceptibility modelling and real-time meteorological and seismic data analysis, scientific prediction of every potentially fatal landslide is not possible in most parts of the world. This is particular the case in steep, unstable, densely-populated country in which heavy rain is common. So how can further events of this type be prevented from turning into disasters? A number of precursory phenomena were noted by local inhabitants at Guinsaugon: a crack around the slope that failed was noticed in May 2005; coconut trees near the northern foot of the landslide scarp began to lean increasingly in the down-slope direction in December 2005; a slope around the northern edge of the 17 February 2006 landslide scarp failed on December 17, 2005; in the 9 days prior to the rockslide, 640 mm of rain fell; 450 mm in a 3-day period. Such phenomena are commonly reported by local inhabitants before large landslides (e.g. Elm, Mayunmarca, and many others). In many cases, therefore, it is in principle possible for local people to avoid the consequences of the landslide if they know enough to act appropriately in response to the precursory phenomena. For this possibility to be realized, appropriate information must be provided to and assimilated by the local population. Useful ways of achieving this include pamphlets, video, TV and radio programs and visits from civil defence personnel. The information must be properly presented; scientific language will be ineffective. A communication pyramid, leading from government agencies to local leaders, can facilitate the rapid availability of the information to all potentially susceptible communities. If science can determine those areas not vulnerable to landslide
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Landslide mobility and hazards: implications of the 2014 Oso disaster
Iverson, Richard M.; George, David L.; Allstadt, Kate E.; Reid, Mark E.; Collins, Brian D.; Vallance, James W.; Schilling, Steve P.; Godt, Jonathan W.; Cannon, Charles; Magirl, Christopher S.; Baum, Rex L.; Coe, Jeffrey A.; Schulz, William; Bower, J. Brent
2015-01-01
Landslides reflect landscape instability that evolves over meteorological and geological timescales, and they also pose threats to people, property, and the environment. The severity of these threats depends largely on landslide speed and travel distance, which are collectively described as landslide “mobility”. To investigate causes and effects of mobility, we focus on a disastrous landslide that occurred on 22 March 2014 near Oso, Washington, USA, following a long period of abnormally wet weather. The landslide's impacts were severe because its mobility exceeded that of prior historical landslides at the site, and also exceeded that of comparable landslides elsewhere. The ∼8×106 m3 landslide originated on a gently sloping (landslide began after about 50 s of preliminary slope movement, and observational evidence supports the hypothesis that the high mobility of the landslide resulted from liquefaction of water-saturated sediment at its base. Numerical simulation of the event using a newly developed model indicates that liquefaction and high mobility can be attributed to compression- and/or shear-induced sediment contraction that was strongly dependent on initial conditions. An alternative numerical simulation indicates that the landslide would have been far less mobile if its initial porosity and water content had been only slightly lower. Sensitive dependence of landslide mobility on initial conditions has broad implications for assessment of landslide hazards.
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Landslide inventory for the Little North Santiam River Basin, Oregon
Sobieszczyk, Steven
2010-01-01
This geodatabase is an inventory of existing landslides in the Little North Santiam River Basin, Oregon (2009). Each landslide feature shown has been classified according to a number of specific characteristics identified at the time recorded in the GIS database. The classification scheme was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009). Several significant landslide characteristics recorded in the database are portrayed with symbology on this map. The specific characteristics shown for each landslide are the activity of landsliding, landslide features, deep or shallow failure, type of landslide movement, and confidence of landslide interpretation. These landslide characteristics are determined primarily on the basis of geomorphic features, or landforms, observed for each landslide. This work was completed as part of the Master's thesis "Turbidity Monitoring and LiDAR Imagery Indicate Landslides are Primary Source of Suspended-Sediment Load in the Little North Santiam River Basin, Oregon, Winter 2009-2010" by Steven Sobieszczyk, Portland State University and U.S. Geological Survey. Data layers in this geodatabase include: landslide deposit boundaries (Deposits); field-verfied location imagery (Photos); head scarp or scarp flanks (Scarp_Flanks); and secondary scarp features (Scarps).The geodatabase template was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009).
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Quick clay and landslides of clayey soils.
Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; De Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel
2009-10-30
We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology.
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Landslide monitoring in the Atlantic Highlands area, New Jersey
Reilly, Pamela A.; Ashland, Francis X.; Fiore, Alex R.
2017-08-25
Shallow and deep-seated landslides have occurred episodically on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of Atlantic Highlands and Highlands) in New Jersey. The oldest documented deep-seated landslide occurred in April 1782 and significantly changed the morphology of the bluff. However, recent landslides have been mostly shallow in nature and have occurred during large storms with exceptionally heavy rainfall. These shallow landslides have resulted in considerable damage to residential property and local infrastructure and threatened human safety.The recent shallow landslides in the area (locations modified from New Jersey Department of Environmental Protection) consist primarily of slumps and flows of earth and debris within areas of historical landslides or on slopes modified by human activities. Such landslides are typically triggered by increases in shallow soil moisture and pore-water pressure caused by sustained and intense rainfall associated with spring nor’easters and late summer–fall tropical cyclones. However, the critical relation between rainfall, soil-moisture conditions, and landslide movement has not been fully defined. The U.S. Geological Survey is currently monitoring hillslopes within the Atlantic Highlands area to better understand the hydrologic and meteorological conditions associated with shallow landslide initiation.
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Caplan-Auerbach, J.
2017-12-01
On the evening of June 17 2017, a massive landslide fell from the wall of the Karrat Fjord, Greenland, generating a tsunami that caused the deaths of four residents in the nearby village of Nuugaatsiaq. The slide took place at a bluff 30 km from the village, where a broadband seismometer (DK.NUUG) is permanently deployed. The landslide generated a seismic signal initially interpreted as a magnitude 4.1 earthquake, as well as a tsunami that initially reached heights exceeding 100 m. Prior to the large seismic signal, however, station NUUG detected a series of several dozen small pulses, most of which were highly similar in time series. The pulses occur more frequently with time, until they effectively merge with the seismic signal of the landslide. The pulses were not detected on any other seismic stations, so their source locations cannot be calculated, but particle motions suggest that they were coming from an azimuth of 30o, consistent with the location of the landslide relative to Nuugaatsiaq. This particular sequence, in which small, repeating earthquakes occur with increasing frequency prior to a landslide, has been observed in at least four other locations: (1) on Mt. Baker (Washington) during an ice avalanche in 1976 (Weaver and Malone, 1979), (2) repeatedly on Iliamna volcano (Alaska) in association with glacial avalanches (Caplan-Auerbach and Huggel, 2007), (3) on Mt. Stellar (Alaska) prior to a 2006 rockfall (Huggel et al., 2010), and (4) as part of the Kausu landslide (Japan), in 2015 (Yamada et al., 2016). In all cases the precursory events exhibited waveform similarity, indicative of a repeating point of failure. These events represent stick-slip behavior at the landslide base. The precursory sequences last several hours, suggesting that detection of these events could provide a means of warning prior to failure. This may be useful in areas where instabilities or incipient failures are evident.
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Object-based Landslide Mapping: Examples, Challenges and Opportunities
Hölbling, Daniel; Eisank, Clemens; Friedl, Barbara; Chang, Kang-Tsung; Tsai, Tsai-Tsung; Birkefeldt Møller Pedersen, Gro; Betts, Harley; Cigna, Francesca; Chiang, Shou-Hao; Aubrey Robson, Benjamin; Bianchini, Silvia; Füreder, Petra; Albrecht, Florian; Spiekermann, Raphael; Weinke, Elisabeth; Blaschke, Thomas; Phillips, Chris
2016-04-01
Over the last decade, object-based image analysis (OBIA) has been increasingly used for mapping landslides that occur after triggering events such as heavy rainfall. The increasing availability and quality of Earth Observation (EO) data in terms of temporal, spatial and spectral resolution allows for comprehensive mapping of landslides at multiple scales. Most often very high resolution (VHR) or high resolution (HR) optical satellite images are used in combination with a digital elevation model (DEM) and its products such as slope and curvature. Semi-automated object-based mapping makes use of various characteristics of image objects that are derived through segmentation. OBIA enables numerous spectral, spatial, contextual and textural image object properties to be applied during an analysis. This is especially useful when mapping complex natural features such as landslides and constitutes an advantage over pixel-based image analysis. However, several drawbacks in the process of object-based landslide mapping have not been overcome yet. The developed classification routines are often rather complex and limited regarding their transferability across areas and sensors. There is still more research needed to further improve present approaches and to fully exploit the capabilities of OBIA for landslide mapping. In this study several examples of object-based landslide mapping from various geographical regions with different characteristics are presented. Examples from the Austrian and Italian Alps are shown, whereby one challenge lies in the detection of small-scale landslides on steep slopes while preventing the classification of false positives with similar spectral properties (construction areas, utilized land, etc.). Further examples feature landslides mapped in Iceland, where the differentiation of landslides from other landscape-altering processes in a highly dynamic volcanic landscape poses a very distinct challenge, and in Norway, which is exposed to multiple
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Landslides Mapped from LIDAR Imagery, Kitsap County, Washington
McKenna, Jonathan P.; Lidke, David J.; Coe, Jeffrey A.
2008-01-01
Landslides are a recurring problem on hillslopes throughout the Puget Lowland, Washington, but can be difficult to identify in the densely forested terrain. However, digital terrain models of the bare-earth surface derived from LIght Detection And Ranging (LIDAR) data express topographic details sufficiently well to identify landslides. Landslides and escarpments were mapped using LIDAR imagery and field checked (when permissible and accessible) throughout Kitsap County. We relied almost entirely on derivatives of LIDAR data for our mapping, including topographic-contour, slope, and hill-shaded relief maps. Each mapped landslide was assigned a level of 'high' or 'moderate' confidence based on the LIDAR characteristics and on field observations. A total of 231 landslides were identified representing 0.8 percent of the land area of Kitsap County. Shallow debris topples along the coastal bluffs and large (>10,000 m2) landslide complexes are the most common types of landslides. The smallest deposit mapped covers an area of 252 m2, while the largest covers 0.5 km2. Previous mapping efforts that relied solely on field and photogrammetric methods identified only 57 percent of the landslides mapped by LIDAR (61 percent high confidence and 39 percent moderate confidence), although nine landslides previously identified were not mapped during this study. The remaining 43 percent identified using LIDAR have 13 percent high confidence and 87 percent moderate confidence. Coastal areas are especially susceptible to landsliding; 67 percent of the landslide area that we mapped lies within 500 meters of the present coastline. The remaining 33 percent are located along drainages farther inland. The LIDAR data we used for mapping have some limitations including (1) rounding of the interface area between low slope surfaces and vertical faces (that is, along the edges of steep escarpments) which results in scarps being mapped too far headward (one or two meters), (2) incorrect laser
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Surveying perceptions of landslide risk management in Norway
Chiu, Jessica Ka Yi; Eidsvig, Unni
2016-04-01
Enhanced precipitation due to climate change leads to increase in both frequency and intensity of landslides in Norway. A proactive approach to risk management is therefore required to significantly reduce the losses associated with landslides. Opinions and perceptions from practitioners on the performance of landslide risk management can provide insights on areas for improvement in the landslide risk management strategies in Norway. The Risk Management Index (RMI), proposed by Cardona et al. (2004), is a well-established method to measure perceptions of disaster management of selected actors holistically. The RMI is measured based on opinion questionnaires to technical staff, decision-makers, and stakeholders involved in all stages of risk reduction strategies. It is a composite index that considers a wide variety of strategies to manage risks, including structural and non-structural measures, acceptance strategies, disaster management, and risk transfer. The RMI method was modified to be implemented in landslide hazards and to fit with Norwegian conditions. An opinion survey was conducted in autumn 2015 to measure perceptions of landslide risk management in Norway. Perceptions were surveyed for two time periods: 2015 and 2050, and are based on national, county, and municipality levels. Based on the survey results, performance of landslide risk management at any administrative levels in Norway is perceived to improve from `significant' in 2015 to `significant' to `outstanding' in 2050. Knowledge and technology, climate, risk perceptions, and anthropogenic activities are mostly considered by respondents for their 2050 perceptions. Several aspects of landslide risk management in Norway can be improved. For example, landslide hazard evaluation and mapping should be prioritised in Norway. Upgrading, retrofitting, and reconstruction of assets may also be included in the landslide risk reduction strategies. In addition, there should be more focus on inter
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Long, A. M.; Hill, J. C.
2017-12-01
In northeastern South Carolina, several shallow (migration of the ancestral Pee Dee River system along the southern limb of the Cape Fear Arch since the Pliocene. These paleo-channel complexes can be traced 80 km across the continental shelf via Boomer and Chirp subbottom data. The Murrells Inlet paleo-channel complex is the most well imaged offshore; and this data coverage provides an opportunity for a detailed seismic stratigraphic interpretation and analysis of downstream variability. Initial observations from this case study indicate that inner shelf incisions, where bedrock is folded and faulted, tend to be shallow with numerous channels, while the incisions across the middle shelf appear to be deeper and contains larger, more sinuous channels that are cut into broadly tilted strata with a gentle south-southeastward dip. This suggests the geometry and spatial distribution of the incisions were a function of the inherited fabric of the underlying basement, which created local deflection and areas of aggradation and degradation. The inner shelf paleo-channel complex fill is dominated by fluvial cut and fill seismic facies, while the middle shelf contains a wide variety of seismic facies (i.e. transparent, layered, chaotic, etc). This overall longitudinal fill pattern is most likely due to each location's general proximity to base level. The variation in the cut and fill seismic facies may be driven by substantial changes in discharge, driven locally by the joining of another major river or by climatic changes in the drainage basin. There also appears to be preferential reoccupation of previously filled paleo-channels, as the basement in this region is Tertiary and Cretaceous carbonates and siliciclastic rocks that are more resistant to erosion. The most recent occupation in any given paleo-channel tends to be on the southern margin, which may imply tectonic forcing from the uplift of the Cape Fear Arch. Preliminary results from this case study suggest that first
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Probabilistic clustering of rainfall condition for landslide triggering
Rossi, Mauro; Luciani, Silvia; Cesare Mondini, Alessandro; Kirschbaum, Dalia; Valigi, Daniela; Guzzetti, Fausto
2013-04-01
Landslides are widespread natural and man made phenomena. They are triggered by earthquakes, rapid snow melting, human activities, but mostly by typhoons and intense or prolonged rainfall precipitations. In Italy mostly they are triggered by intense precipitation. The prediction of landslide triggered by rainfall precipitations over large areas is commonly based on the exploitation of empirical models. Empirical landslide rainfall thresholds are used to identify rainfall conditions for the possible landslide initiation. It's common practice to define rainfall thresholds by assuming a power law lower boundary in the rainfall intensity-duration or cumulative rainfall-duration space above which landslide can occur. The boundary is defined considering rainfall conditions associated to landslide phenomena using heuristic approaches, and doesn't consider rainfall events not causing landslides. Here we present a new fully automatic method to identify the probability of landslide occurrence associated to rainfall conditions characterized by measures of intensity or cumulative rainfall and rainfall duration. The method splits the rainfall events of the past in two groups: a group of events causing landslides and its complementary, then estimate their probabilistic distributions. Next, the probabilistic membership of the new event to one of the two clusters is estimated. The method doesn't assume a priori any threshold model, but simple exploits the real empirical distribution of rainfall events. The approach was applied in the Umbria region, Central Italy, where a catalogue of landslide timing, were obtained through the search of chronicles, blogs and other source of information in the period 2002-2012. The approach was tested using rain gauge measures and satellite rainfall estimates (NASA TRMM-v6), allowing in both cases the identification of the rainfall condition triggering landslides in the region. Compared to the other existing threshold definition methods, the prosed
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Supporting response with science: the Oso, Washington, landslide
Godt, J.
2014-12-01
On 22 March 2014 a large, rapidly moving landslide impacted the community of Steelhead Haven, near Oso, Washington, killing 43 people. The slide displaced about 8 million m3 of sand and silt from a 200-m high glacial terrace destroying 40 homes and burying more than 1.0 km of State Route 530. The landslide temporarily dammed the North Fork of the Stillaguamish River flooding an area of about 1.4 km2. The unusually long travel distance, in excess of 700 m from the base of the slope, and apparent speed of the slide led to the great loss of life and destruction. Landslide science was critical in supporting the response to the disaster. Landslide monitoring, process understanding, pre- and post-event high-resolution digital topography, and numerical simulations were used to advise search operations. Recognizing that buildings and their contents were swept tens to hundreds of meters from their original locations, maps of deposit thickness, and estimates of landslide trajectories were used to develop safer and more efficient search strategies. Teams of county, state, and federal scientists, engineers, and specialists were formed to assess the stability of the landslide dam and to monitor stream flow and the level of the lake impounded by the slide, and to assess the geomorphic response of the river to the landslide for gauging future effects on flood hazards and aquatic ecosystems. Another scientific team assessed the threat of additional landslide activity to search operations. This team's activities included establishing a communications protocol among landslide watch officers and search operations, deploying instrument platforms developed for use on volcanoes (Spiders) to remotely detect ground movement by means of GPS technology and to detect vibrations indicative of landslide movement using seismometers. The team was responsible for monitoring and integrating data from the Spiders and other instruments and making determinations with regards to the potential for
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Prediction of Rainfall-Induced Landslides
Nadim, F.; Sandersen, F.
2009-12-01
Rainfall-induced landslides can be triggered by two main mechanisms: shear failure due to build-up of pore water pressure and erosion by surface water runoff when flow velocity exceeds a critical value. Field measurements indicate that, in the initial phase, the slip surface of a landslide often occurs along the top of a relatively impermeable layer located at some depth within the soil profile, e.g. at the contact with a shallow underlying bedrock or parent rock. The shear strength along this surface and hence the stability of the slope is governed by the pore water pressure. The pore pressure is in turn controlled by water seepage through the slope, either from infiltrated rain, or from groundwater that follows bedrock joints and soil layers with high permeability. When the infiltration rate of the underlying layer is too low for further downward penetration of water or when a wetting front is produced, pore water pressure builds up, reducing the soil shear strength. During high intensity rainfall, surface water runoff will exert shear stresses on the bed material. De-pending on the grain size distribution and specific gravity of the material, erosion might occur when the flow velocity exceeds a critical value. As erosion progresses and sediment concentration increases, the flow regime may become unstable with heavy erosion at high flow velocity locations triggering a debris flow. In many cases, previous landslides along steep gully walls have fed an abundance of loose soil material into the gullies. Landslides along gully walls that obstruct the water transport may also trigger debris flows when the landslide-dam collapses, creating a surge downstream. Both the long-duration (1 or more days) and short-duration precipitation (of the order of 1 hour) are significant in the triggering of shallow landslides, since the critical short-duration rainfall intensity reduces as the antecedent accumulated rainfall increases. Experiences in Norway indicate that the maxi
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Geomodels of coseismic landslides environments in Central Chile.
Serey, A.; Sepulveda, S. A.; Murphy, W.; Petley, D. N.
2017-12-01
Landslides are a major source of fatalities and damage during strong earthquakes in mountain areas. Detailed geomodels of coseismic landslides environments are essential parts of seismic landslide hazard analyses. The development of a site specific geological model is required, based on consideration of the regional and local geological and geomorphological history and the current ground surface conditions. An engineering geological model is any approximation of the geological conditions, at varying scales, created for the purpose of solving an engineering problem. In our case, the objective is the development of a methodology for earthquake-induced landslide hazard assessment applicable to urban/territorial planning and disaster prevention strategies assessment at a regional scale adapted for the Chilean tectonic conditions. We have developed the only 2 complete inventories of landslides triggered by earthquakes in Chile. The first from the Mw 6.2, shallow crustal Aysén earthquake in 2007. Second one from the Mw 8.8, megathrust subduction Maule earthquake in 2010. From the comparison of these 2 inventories with others from abroad, as well as analysis of large, prehistoric landslide inventories proposed as likely induced by seismic activity we have determined topographic, geomorphological, geological and seismic controlling factors in the occurrence of earthquake-triggered landslides. With the information collected we have defined different environments for generation of coseismic landslides based on the construction of geomodels. As a result we have built several geomodels in the Santiago Cordillera in central Chile (33°S), based upon the San Ramón Fault, a west-vergent reverse fault that outcrops at the edge of Santiago basin recently found to be active and a likely source of seismic activity in the future, with potential of triggering landslides in the Santiago mountain front as well as inland into the Mapocho and Maipo Cordilleran valleys. In conclusion
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Solid discharge and landslide activity at basin scale
Ardizzone, F.; Guzzetti, F.; Iadanza, C.; Rossi, M.; Spizzichino, D.; Trigila, A.
2012-04-01
This work presents a preliminary analysis aimed at understanding the relationship between landslide sediment supply and sediment yield at basin scale in central and southern Italy. A database of solid discharge measurements regarding 116 gauging stations, located along the Apennines chain in Italy, has been compiled by investigating the catalogues, named Annali Idrologici, published by Servizio Idrografico e Mareografico Italiano in the period from 1917 to 1997. The database records several information about the 116 gauging stations, and especially reports the sediment yield monthly measurements (103 ton) and the catchments area (km2). These data have been used to calculate the average solid yield and the normalized solid yield for each station in the observation period. The Italian Landslide Inventory (Progetto IFFI) has been used to obtained the size of the landslides, in order to estimate the landslide mobilization rates. The IFFI Project funded by the Italian Government is realized by ISPRA (Italian National Institute for Environmental Protection and Research - Geological Survey of Italy) in partnership with the 21 Regions and Self Governing Provinces. 21 of the 116 gauging stations and the related catchments have been selected on the basis of the length of the solid discharge observation period and excluding the catchments with dams located upstream the stations. The landslides inside the selected catchments have been extracted from the IFFI inventory, calculating the planimetric area of each landslide. Considering both the shallow and deep landslides, the landslide volume has been estimated using an empirical power law relation (landslide area vs. volume). The total landslide volume in the study areas and the average sediment yield measured at the gauging stations have been compared, analysing the behaviour of the basins which drainage towards the Tyrrhenian sea and the basins which drainage towards the Adriatic sea.
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Department of Homeland Security — These data are a digital version of U.S. Geological Survey Professional Paper 1183, Landslide Overview Map of the Conterminous United States. The map and digital...
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Tanyas, Hakan; Van Westen, Cees J.; Allstadt, Kate E.; Anna Nowicki Jessee, M.; Görüm, Tolga; Jibson, Randall W.; Godt, Jonathan W.; Sato, Hiroshi P.; Schmitt, Robert G.; Marc, Odin; Hovius, Niels
2017-01-01
Earthquake‐induced landslide (EQIL) inventories are essential tools to extend our knowledge of the relationship between earthquakes and the landslides they can trigger. Regrettably, such inventories are difficult to generate and therefore scarce, and the available ones differ in terms of their
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Landslide mobility and hazards: implications of the 2014 Oso disaster
Iverson, R. M.; George, D. L.; Allstadt, K.; Reid, M. E.; Collins, B. D.; Vallance, J. W.; Schilling, S. P.; Godt, J. W.; Cannon, C. M.; Magirl, C. S.; Baum, R. L.; Coe, J. A.; Schulz, W. H.; Bower, J. B.
2015-02-01
Landslides reflect landscape instability that evolves over meteorological and geological timescales, and they also pose threats to people, property, and the environment. The severity of these threats depends largely on landslide speed and travel distance, which are collectively described as landslide "mobility". To investigate causes and effects of mobility, we focus on a disastrous landslide that occurred on 22 March 2014 near Oso, Washington, USA, following a long period of abnormally wet weather. The landslide's impacts were severe because its mobility exceeded that of prior historical landslides at the site, and also exceeded that of comparable landslides elsewhere. The ∼ 8 ×106 m3 landslide originated on a gently sloping (<20°) riverside bluff only 180 m high, yet it traveled across the entire ∼1 km breadth of the adjacent floodplain and spread laterally a similar distance. Seismological evidence indicates that high-speed, flowing motion of the landslide began after about 50 s of preliminary slope movement, and observational evidence supports the hypothesis that the high mobility of the landslide resulted from liquefaction of water-saturated sediment at its base. Numerical simulation of the event using a newly developed model indicates that liquefaction and high mobility can be attributed to compression- and/or shear-induced sediment contraction that was strongly dependent on initial conditions. An alternative numerical simulation indicates that the landslide would have been far less mobile if its initial porosity and water content had been only slightly lower. Sensitive dependence of landslide mobility on initial conditions has broad implications for assessment of landslide hazards.
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Global Scale Analysis of Martian Landslide Mobility and Paleoenvironmental Clues
Crosta, Giovanni Battista; De Blasio, Fabio Vittorio; Frattini, Paolo
2018-04-01
The mobility of landslides on Mars is studied based on a database of 3,118 events. To establish the volume of the landslides for the whole data set based on the deposit area, a new volume-area relationship based on a representative data set of 222 landslides is used. By plotting the H/L ratio between fall height H and runout L versus volume, the landslide mobility is analyzed and compared with existing empirical relationships for Martian and terrestrial landslides. By analyzing the mobility in terms of normalized residuals, that is, the relative deviation of the H/L ratio from the data set best-fit line, mobility is found to depend on both the landslide location on Mars and the landslide typology. This allows us to identify four different types of high-mobility (hypermobile) landslides. Three classes of high-mobility landslides are associated respectively to meteoroid impact, the Olympus Mons aureoles, and landslides with Toreva-block failure style, and their mobility can be explained by the peculiar flow mechanics. The fourth class includes landslides associated with isolated craters, those in the regions wetted by the putative Oceanus Borealis, and the ones at high latitudes. We suggest that the common factor behind all the hypermobile landslides of this fourth kind is the presence of ice. This is confirmed by our data showing that landslides increase in mobility with latitude. The latitudinal trend mirrors the distribution of ice as detected by radar, neutron probes, and the presence of glacial and layered ejecta morphologies. Because the overall landslide distribution supports the presence of ice-lubricated conditions, two ice lubrication models are presented showing how ice melting within or underneath the landslides could enhance mobility. By proper analysis in terms of apparent friction residuals, we find that the mobility of landslides in Valles Marineris with the largest landslide concentration is lower than average. We explain this circumstance partly
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Galang, J. A. M. B.; Eco, R. C.; Lagmay, A. M. A.
2014-12-01
The M_w 7.2 October 15, 2013 Bohol earthquake is one of the more destructive earthquake to hit the Philippines in the 21st century. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". The earthquake resulted in 209 fatalities and over 57 million USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparations for this type of landslides rely heavily on the identification of fracture-related slope instability. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations of discontinuity sets were mapped using remote sensing techniques with the aid of a Digital Terrain Model (DTM) obtained in 2012. The DTM used is an IFSAR derived image with a 5-meter pixel resolution and approximately 0.5 meter vertical accuracy. Coltop 3D software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. Separately, a manually derived landslide inventory has been performed using post-earthquake satellite images and LIDAR. The results were compared to the landslide inventory which identified at least 873 landslides. Out of the 873 landslides identified through the inventory, 786 or 90% intersect the simulated structural-controlled landslide hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow
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Hydroclimatic conditions preceding the March 2014 Oso landslide
Henn, Brian; Cao, Qian; Lettenmaier, Dennis P.; Magirl, Christopher S.; Mass, Clifford; Bower, J. Brent; St. Laurent, Michael; Mao, Yixin; Perica, Sanja
2015-01-01
The 22 March 2014 Oso landslide was one of the deadliest in U.S. history, resulting in 43 fatalities and the destruction of more than 40 structures. We examine synoptic conditions, precipitation records and soil moisture reconstructions in the days, months, and years preceding the landslide. Atmospheric reanalysis shows a period of enhanced moisture transport to the Pacific Northwest beginning on 11 February 2014. The 21- to 42-day periods prior to the landslide had anomalously high precipitation; we estimate that 300-400 mm of precipitation fell at Oso in the 21 days prior to the landslide. Relative only to historical periods ending on 22 March, the return periods of these precipitation accumulations are large (25-88 years). However, relative to the largest accumulations from any time of the year (annual maxima), return periods are more modest (2-6 years). In addition to the 21-42 days prior to the landslide, there is a secondary maximum in the precipitation return periods for the 4 years preceding the landslide. Reconstructed soil moisture was anomalously high prior to the landslide, with a return period that exceeded 40 years about a week before the event.
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Determining rainfall thresholds that trigger landslides in Colombia
International Nuclear Information System (INIS)
Mayorga Marquez, Ruth
2003-01-01
Considering that rainfall is the natural event that more often triggers landslides, it is important to study the relationship between this phenomenon and the occurrence of earth mass movements, by determining rainfall thresholds that trigger landslides in different zones of Colombia. The research presents a methodology that allows proposing rainfall thresholds that trigger landslides in Colombia, by means of a relationship between the accumulated rain in the soil (antecedent rainfall) and the rain that falls the day of the landslide occurrence (event rainfall)
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Macario Galang, Jan Albert; Narod Eco, Rodrigo; Mahar Francisco Lagmay, Alfredo
2015-04-01
The M 7.2 October 15, 2013 Bohol earthquake is the most destructive earthquake to hit the Philippines since 2012. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". Its name, taken after the barangay (village) where the fault is best exposed and was first seen. The earthquake resulted in 209 fatalities and over 57 billion USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparedness against this type of landslide therefore, relies heavily on the identification of fracture-related unstable slopes. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations or discontinuity sets were mapped in the field with the aid of a 2012 IFSAR Digital Terrain Model (DTM) with 5-meter pixel resolution and software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. The results were compared to a post-earthquake landslide inventory of 456 landslides. Out the total number of landslides identified from post-earthquake high-resolution imagery, 366 or 80% intersect the structural-controlled hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow paths, located structurally-controlled unstable zones can be used to mark unsafe areas for settlement. The method can be further improved with the
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Landslide Susceptibility Statistical Methods: A Critical and Systematic Literature Review
Mihir, Monika; Malamud, Bruce; Rossi, Mauro; Reichenbach, Paola; Ardizzone, Francesca
2014-05-01
Landslide susceptibility assessment, the subject of this systematic review, is aimed at understanding the spatial probability of slope failures under a set of geomorphological and environmental conditions. It is estimated that about 375 landslides that occur globally each year are fatal, with around 4600 people killed per year. Past studies have brought out the increasing cost of landslide damages which primarily can be attributed to human occupation and increased human activities in the vulnerable environments. Many scientists, to evaluate and reduce landslide risk, have made an effort to efficiently map landslide susceptibility using different statistical methods. In this paper, we do a critical and systematic landslide susceptibility literature review, in terms of the different statistical methods used. For each of a broad set of studies reviewed we note: (i) study geography region and areal extent, (ii) landslide types, (iii) inventory type and temporal period covered, (iv) mapping technique (v) thematic variables used (vi) statistical models, (vii) assessment of model skill, (viii) uncertainty assessment methods, (ix) validation methods. We then pulled out broad trends within our review of landslide susceptibility, particularly regarding the statistical methods. We found that the most common statistical methods used in the study of landslide susceptibility include logistic regression, artificial neural network, discriminant analysis and weight of evidence. Although most of the studies we reviewed assessed the model skill, very few assessed model uncertainty. In terms of geographic extent, the largest number of landslide susceptibility zonations were in Turkey, Korea, Spain, Italy and Malaysia. However, there are also many landslides and fatalities in other localities, particularly India, China, Philippines, Nepal and Indonesia, Guatemala, and Pakistan, where there are much fewer landslide susceptibility studies available in the peer-review literature. This
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Development of geoportal for landslide monitoring
Directory of Open Access Journals (Sweden)
Sladić Dubravka
2012-01-01
Full Text Available The paper presents the implementation of geoportal for landslide monitoring which which includes two subsystems: a system for acquisition, storage and distribution of data on landslides and real time alert system. System for acquisition, storage and distribution of data on landslides include raster and vector spatial data on landslides affected areas, as well as metadata. Alert system in real time is associated with a sensor for detecting displacement, which performs constant measurements and signals in case of exceeding the reference value. The system was developed in accordance with the standards in the field of GIS: ISO 19100 series of standards and OpenGIS Consortium and is based on service-oriented architecture and principles of spatial data infrastructures. [Projekat Ministarstva nauke Republike Srbije, br. TR37017: Modeliranje stanja i strukture padinskih procesa primenom GNSS i tehnologija skeniranja laserom i georadarom
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Czech Academy of Sciences Publication Activity Database
Klimeš, Jan; Stemberk, Jakub; Blahůt, Jan; Krejčí, V.; Krejčí, O.; Hartvich, Filip; Kycl, P.
2017-01-01
Roč. 14, č. 2 (2017), s. 771-780 ISSN 1612-510X R&D Projects: GA MŠk(CZ) LG15007 Institutional support: RVO:67985891 Keywords : landslide inventory * ICL/IPL activities * landslide cost * landslide risk * fatal landslides * public awareness Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 3.657, year: 2016
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Landslide Hazard-Prevention in Balakot Region, Pakistan
Directory of Open Access Journals (Sweden)
Abdul Salam Soomro
2012-04-01
Full Text Available The earthquake triggered enormous landslides on 8th October 2005 in the various areas of Pakistan especially in Balakot Region. This research paper fulfilled the urge to develop alternative landslide planning based on the consideration of landslide preventing measures using GIS (Geographical Informaton Systems techniques. This specific type of land use planning differs from traditional type of land use planning due to consideration of the probable hazard of landslide disaster by applying zonation methodology for finding the appropriate suitable areas for various development purposes. The various parameters e.g. elevation, slope angle, forest/ vegetations, faults, landslide zones, and rainfall were utilized as GIS data themes in the vector format. The different GIS techniques were used: (i Clipping the data layers; (ii Spatial analysis by converting the vector layers into raster format; (iii Classification of data themes into certain classes; (iv Overlaying the data themes and (v Map calculation techniques through GIS standard software. This applied research has found that various different regions such as high suitable, moderate suitable, low suitable and unsuitable may be considered as preventive measures from the probable hazard of the landslide disaster in future for rehabilitation and redevelopment purpose which can save human lives, residential and commercial infrastructure in future. It is believed that the various predicted regions for preventing landslide hazards can be very beneficial to the decision makers for the redevelopment of the region in future.
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Landslide Hazard-Prevention in Balakot Region, Pakistan
International Nuclear Information System (INIS)
Soomro, A.S.
2011-01-01
The earthquake triggered enormous landslides on October 8, 2005 in the various areas of Pakistan especially in Balakot Region. This research paper fulfilled the urge to develop alternative landslide planning based on the consideration of landslide preventing measures using GIS (Geographical Information Systems) techniques. This specific type of land use planning differs from traditional type of land use planning due to consideration of the probable hazard of landslide disaster by applying zonation methodology for finding the appropriate suitable areas for various development purposes. The various parameters e.g. elevation, slope angle, forest/ vegetations, faults, landslide zones, and rainfall were utilized as GIS data themes in the vector format. The different GIS techniques were used: (i) Clipping the data layers; (II) Spatial analysis by converting the vector layers into raster format; (III) Classification of data themes into certain classes; (IV) Overlaying the data themes and (v) Map calculation techniques through GIS standard software. This applied research has found that various different regions such as high suitable, moderate suitable, low suitable and unsuitable may be considered as preventive measures from the probable hazard of the landslide disaster in future for rehabilitation and redevelopment purpose which can save human lives, residential and commercial infrastructure in future. It is believed that the various predicted regions for preventing landslide hazards can be very beneficial to the decision makers for the redevelopment of the region in future. (author)
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TRIGRS Application for landslide susceptibility mapping
Sugiarti, K.; Sukristiyanti, S.
2018-02-01
Research on landslide susceptibility has been carried out using several different methods. TRIGRS is a modeling program for landslide susceptibility by considering pore water pressure changes due to infiltration of rainfall. This paper aims to present a current state-of-the-art science on the development and application of TRIGRS. Some limitations of TRIGRS, some developments of it to improve its modeling capability, and some examples of the applications of some versions of it to model the effect of rainfall variation on landslide susceptibility are reviewed and discussed.
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Junginger, Annett
2017-04-01
A major challenge in paleo-anthropology is to understand the impact of climatic changes on human evolution. The Hominin Sites and Paleo-lakes Drilling Project (HSPDP) is currently meeting that challenge by providing records that cover the last 3.7 Ma of paleoenvironmental change all located in close proximity to key paleo-anthropological findings in East Africa. One of the cored climatic archives comes from the Chew Bahir basin in southern Ethiopia, where duplicate sediment cores provide valuable insights about East African environmental variability during the last 550 ka. The lake basins in the eastern branch of the East African Rift System today contain mainly shallow and alkaline lakes. However, paleo-shorelines in the form of wave cut notches, shell beds, and beach ridges are common morphological evidences for deep freshwater lakes that have filled the basins up to their overflow level during pronounced humid episodes, such as the African Humid Period (15-5 ka). Unfortunately, further back in time, many of those morphological features disappear due to erosion and the estimation of paleo-water depths depend merely on qualitative proxies from core analyses. We here present a method that shows high potential to translate qualitative proxy signals from sediment core analyses to quantitative climate signals in the Ethiopian Rift. The method aims at water level reconstruction in the Chew Bahir basin using strontium isotope ratios (87Sr/86Sr, SIR) in lacustrine microfossils. SIR reflect the lithology of the drained catchment. SIR have changed pronouncedly when higher elevated paleo-lakes Abaya, Chamo and Awassa were overflowing into paleo-lake Chew Bahir. This new method may help to quantify paleo-lake levels beyond the past 20 ka and may also detect migrational barriers or routes due to the occurrence of synchronous large, connected and deep paleo-lakes.
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Object-based landslide detection in different geographic regions
Friedl, Barbara; Hölbling, Daniel; Eisank, Clemens; Blaschke, Thomas
2015-04-01
Landslides occur in almost all mountainous regions of the world and rank among the most severe natural hazards. In the last decade - according to the world disaster report 2014 published by the International Federation of Red Cross and Red Crescent Societies (IRFC) - more than 9.000 people were killed by mass movements, more than 3.2 million people were affected and the total amount of disaster estimated damage accounts to more than 1.700 million US dollars. The application of remote sensing data for mapping landslides can contribute to post-disaster reconstruction or hazard mitigation, either by providing rapid information about the spatial distribution and location of landslides in the aftermath of triggering events or by creating and updating landslide inventories. This is especially valid for remote and inaccessible areas, where information on landslides is often lacking. However, reliable methods are needed for extracting timely and relevant information about landslides from remote sensing data. In recent years, novel methods such as object-based image analysis (OBIA) have been successfully employed for semi-automated landslide mapping. Several studies revealed that OBIA frequently outperforms pixel-based approaches, as a range of image object properties (spectral, spatial, morphometric, contextual) can be exploited during the analysis. However, object-based methods are often tailored to specific study areas, and thus, the transferability to regions with different geological settings, is often limited. The present case study evaluates the transferability and applicability of an OBIA approach for landslide detection in two distinct regions, i.e. the island of Taiwan and Austria. In Taiwan, sub-areas in the Baichi catchment in the North and in the Huaguoshan catchment in the southern-central part of the island are selected; in Austria, landslide-affected sites in the Upper Salzach catchment in the federal state of Salzburg are investigated. For both regions
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Monitoring and Warning of Landslides Based On Rainfall
Yudhbir, Y.
Management issues of landslide hazards assume much greater significance in poorest segments of society living in landslide risk prone hilly areas in developing countries. Analysis of the temporal recurrence of landslides shows that disastrous events occur with a frequency higher than the social and economic capacity of these societies to recover from previous events. In the context of landslide hazard management in In- dian Himalayan states this problem assumes much greater significance. Majority of the population lives on hill slopes which experience repeated landsliding activity es- pecially during the summer monsoon rains. Considering the high cost of structural control measures and the lack of necessary spatial database in respect of Quaternary geology, detailed topography and geohydrology etc., there is an acute need to develop a monitoring and warning system which is economical, easy to operate and does not require high technological inputs. Since most of the landslides in these areas are triggered by high incidence of rain, it appears attractive to explore development of a monitoring and warning network based on critical rainfall intensity thresholds. Such an option for management of landslide hazards would also provide useful meteorological data required for assessment of wa- ter resources, soil loss due to erosion, agricultural practices and flood incidence. In this paper, available approaches to the prediction and warning of landslide based on rainfall data will be critically reviewed. Various criteria recommended in litera- ture for threshold rainfall values in rain induced ground movements/failures would be compared and these relationships will be contrasted with the limited data available for the Indian Himalayan landslides. A plan for a network of automatic rain gauges and a suitable warning system will be discussed.
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Methods of Measuring and Mapping of Landslide Areas
Skrzypczak, Izabela; Kokoszka, Wanda; Kogut, Janusz; Oleniacz, Grzegorz
2017-12-01
The problem of attracting new investment areas and the inability of current zoning areas, allows us to understand why it is impossible to completely rule out building on landslide areas. Therefore, it becomes important issue of monitoring areas at risk of landslides. Only through appropriate monitoring and proper development of measurements resulting as maps of areas at risk of landslides enables us to estimate the risk and the relevant economic calculation for the realization of the anticipated investment in such areas. The results of monitoring of the surface and in-depth of the landslides are supplemented with constant observation of precipitation. The previous analyses and monitoring of landslides show that some of them are continuously active. GPS measurements, especially with laser scanning provide a unique activity data acquired on the surface of each individual landslide. The development of high resolution numerical models of terrain and the creation of differential models based on subsequent measurements, informs us about the size of deformation, both in units of distance (displacements) and volume. The compatibility of the data with information from in-depth monitoring allows the generation of a very reliable in-depth model of landslide, and as a result proper calculation of the volume of colluvium. Programs presented in the article are a very effective tool to generate in-depth model of landslide. In Poland, the steps taken under the SOPO project i.e. the monitoring and description of landslides are absolutely necessary for social and economic reasons and they may have a significant impact on the economy and finances of individual municipalities and also a whole country economy.
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Directory of Open Access Journals (Sweden)
RODRIGO I. CERRI
2017-08-01
Full Text Available ABSTRACT This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high slopes and many geological structures in a gneiss - migmatitic terrain. In contrast to traditional approaches, this method proposes that structural data (foliation, fractures and bedding planes and its relation with the slope geometry, is important to be consider in the landslide zonation hazard, along with declivity, relative relief, soil and rock properties, land use and vegetation cover and hydrogeological and climate factors. Results show that slopes with high hazard have the same dip direction of geological structures. Landslide zonation hazard using structural data contributes to a better understanding of how these structures, preserved in tropical residual soils, influence on slope stability and generates landslides.
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Cerri, Rodrigo I; Reis, Fábio A G V; Gramani, Marcelo F; Giordano, Lucilia C; Zaine, José Eduardo
2017-01-01
This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high slopes and many geological structures in a gneiss - migmatitic terrain. In contrast to traditional approaches, this method proposes that structural data (foliation, fractures and bedding planes) and its relation with the slope geometry, is important to be consider in the landslide zonation hazard, along with declivity, relative relief, soil and rock properties, land use and vegetation cover and hydrogeological and climate factors. Results show that slopes with high hazard have the same dip direction of geological structures. Landslide zonation hazard using structural data contributes to a better understanding of how these structures, preserved in tropical residual soils, influence on slope stability and generates landslides.
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Landslide susceptibility map: from research to application
Fiorucci, Federica; Reichenbach, Paola; Ardizzone, Francesca; Rossi, Mauro; Felicioni, Giulia; Antonini, Guendalina
2014-05-01
Susceptibility map is an important and essential tool in environmental planning, to evaluate landslide hazard and risk and for a correct and responsible management of the territory. Landslide susceptibility is the likelihood of a landslide occurring in an area on the basis of local terrain conditions. Can be expressed as the probability that any given region will be affected by landslides, i.e. an estimate of "where" landslides are likely to occur. In this work we present two examples of landslide susceptibility map prepared for the Umbria Region and for the Perugia Municipality. These two maps were realized following official request from the Regional and Municipal government to the Research Institute for the Hydrogeological Protection (CNR-IRPI). The susceptibility map prepared for the Umbria Region represents the development of previous agreements focused to prepare: i) a landslide inventory map that was included in the Urban Territorial Planning (PUT) and ii) a series of maps for the Regional Plan for Multi-risk Prevention. The activities carried out for the Umbria Region were focused to define and apply methods and techniques for landslide susceptibility zonation. Susceptibility maps were prepared exploiting a multivariate statistical model (linear discriminant analysis) for the five Civil Protection Alert Zones defined in the regional territory. The five resulting maps were tested and validated using the spatial distribution of recent landslide events that occurred in the region. The susceptibility map for the Perugia Municipality was prepared to be integrated as one of the cartographic product in the Municipal development plan (PRG - Piano Regolatore Generale) as required by the existing legislation. At strategic level, one of the main objectives of the PRG, is to establish a framework of knowledge and legal aspects for the management of geo-hydrological risk. At national level most of the susceptibility maps prepared for the PRG, were and still are obtained
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Samia, Jalal; Temme, Arnaud; Bregt, Arnold; Wallinga, Jakob; Guzzetti, Fausto; Ardizzone, Francesca; Rossi, Mauro
2017-01-01
Landslides are a major category of natural disasters, causing loss of lives, livelihoods and property. The critical roles played by triggering (such as extreme rainfall and earthquakes), and intrinsic factors (such as slope steepness, soil properties and lithology) have previously successfully
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Assessments on landslide susceptibility in the Tseng-wen reservoir watershed, Taiwan
Chen, Yu-Chin; Chen, Yung-Chau; Chen, Wen-Fu
2014-05-01
Typhoon Morakot under the strong influence of southwestern monsoon wind struck Taiwan on 8 August 2009, and dumped record-breaking rains in southern Taiwan. It triggered enormous landslides in mountains and severe flooding in low-lying areas. In addition, it destroyed or damaged houses, agricultural fields, roads, bridges, and other infrastructure facilities, causing massive economic loss and, more tragically, human casualties. In order to evaluate landslide hazard and risk assessment, it is important to understand the potential sites of landslide and their spatial distribution. Multi-temporal satellite images and geo-spatial data are used to build landslide susceptibility map for the post-disaster in the Tseng-wen reservoir watershed in this research. Elevation, slope, aspect, NDVI (normalized differential vegetation index), relief, roughness, distance to river, and distance to road are the considered factors for estimating landslide susceptibility. Maximum hourly rainfall and total rainfall, accompanied with typhoon event, are selected as the trigger factors of landslide events. Logistic regression analysis is adopted as the statistical method to model landslide susceptibility. The assessed susceptibility is represented in 4 levels which are high, high-intermediate, intermediate, and low level, respectively. Landslide spatial distribution can be depicted as a landslide susceptibility map with respect to each considered influence factors for a specified susceptible level. The landslide areas are about 358 ha and 1,485 ha before and after typhoon Morakot. The new landslide area, induced by typhoon Morakot, is as almost 4 times as the landslide area before typhoon Morakot. In addition, there is about 44.56% landslide area elevation ranging from 500m to 1000m and about 57.22% average slope ranging from 30° to 45° of landslide area. Furthermore, the devastating landslides were happened at those sites close to rivers, exposed area, and area with big land cover change
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Application of Video Recognition Technology in Landslide Monitoring System
Directory of Open Access Journals (Sweden)
Qingjia Meng
2018-01-01
Full Text Available The video recognition technology is applied to the landslide emergency remote monitoring system. The trajectories of the landslide are identified by this system in this paper. The system of geological disaster monitoring is applied synthetically to realize the analysis of landslide monitoring data and the combination of video recognition technology. Landslide video monitoring system will video image information, time point, network signal strength, power supply through the 4G network transmission to the server. The data is comprehensively analysed though the remote man-machine interface to conduct to achieve the threshold or manual control to determine the front-end video surveillance system. The system is used to identify the target landslide video for intelligent identification. The algorithm is embedded in the intelligent analysis module, and the video frame is identified, detected, analysed, filtered, and morphological treatment. The algorithm based on artificial intelligence and pattern recognition is used to mark the target landslide in the video screen and confirm whether the landslide is normal. The landslide video monitoring system realizes the remote monitoring and control of the mobile side, and provides a quick and easy monitoring technology.
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Slope failures in surface mines, methods of studying landslides
Energy Technology Data Exchange (ETDEWEB)
Flisiak, J; Korman, S; Mazurek, J
1977-01-01
This paper presents a review of methods of measuring landslide fissures, displacement of ground surface points in the landslide area and of points inside the landslide. An analysis of the landslide process is given, stressing various stages and phases of a landslide. Studies carried out by the Institute of Mining Geomechanics of the Technical University of Mining and Metallurgy in Cracow are evaluated. The studies concentrated on the final state of slopes in brown coal surface mines after a landslide occurs. The necessity of developing an apparatus for continuous recording of displacements of points on a landslide surface is stressed. An apparatus developed by the Institute and used for continuous measuring and recording of displacements is described. The apparatus is used to measure displacements of points during the initial phase of a landslide and during the phase of the largest displacements. The principle of the system consists in locating a number of observation points on the ground and a slope. The points are connected among themselves by flexible connectors. The connectors are equipped with potentiometric transmitters which transform the relative displacements into electric pulses. These pulses are recorded by a conventional recording apparatus. (55 refs.) (In Polish)
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Landslide susceptibility zonation in part of Tehri reservoir region
Indian Academy of Sciences (India)
Fuzzy logic; landslide susceptibility; frequency ratio. ... zones using landslide frequency ratio and fuzzy logic in GIS environment is presented for Tehri ... Temporal remote sensing data was used to prepare important landslide causative factor ...
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Hydrologic Controls on Shallow Landslide Location, Size, and Shape
Bellugi, D.; Milledge, D.; Perron, T.; McKean, J. A.; Dietrich, W.; Rulli, M.
2012-12-01
Shallow landslides, typically involving just the soil mantle, are principally controlled by topography, soil and root strengths, and soil thickness, and are typically triggered by storm-induced increases in pore water pressure. The response of a landscape to landslide-triggering storms will thus depend on factors such as rainfall totals, storm intensity and duration, and antecedent moisture conditions. The two dominant mechanisms that generate high pore water pressures at a point are topographically-steered lateral subsurface flow (over timescales of days to weeks), and rapid vertical infiltration (over timescales of minutes to hours). We aim to understand the impact of different storm characteristics and hydrologic regimes on shallow landslide location, size, and shape. We have developed a regional-scale model, which applies a low-parameter grid-based multi-dimensional slope stability model within a novel search algorithm, to generate discrete landslide predictions. This model shows that the spatial organization of parameters such as root strength and pore water pressure has a strong control on shallow landslide location, size, and shape. We apply this model to a field site near Coos Bay, OR, where a ten-year landslide inventory has been mapped onto high-resolution topographic data. Our model predicts landslide size generally increases with increasing rainfall intensity, except when root strength is extremely high and pore pressures are topographically steered. The distribution of topographic index values (the ratios of contributing area to slope) of predicted landslides is a clear signature of the pore water pressure generation mechanism: as laterally dominated flow increases, landslides develop in locations with lower slopes and higher contributing areas; in contrast, in the case of vertically-dominated pore pressure rise, landslides are consistently found in locations with higher slopes and lower contributing areas. While in both cases landslides are found in
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Landslide deposit boundaries for the Little North Santiam River Basin, Oregon
Sobieszczyk, Steven
2010-01-01
This layer is an inventory of existing landslides deposits in the Little North Santiam River Basin, Oregon (2009). Each landslide deposit shown on this map has been classified according to a number of specific characteristics identified at the time recorded in the GIS database. The classification scheme was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009). Several significant landslide characteristics recorded in the database are portrayed with symbology on this map. The specific characteristics shown for each landslide are the activity of landsliding, landslide features, deep or shallow failure, type of landslide movement, and confidence of landslide interpretation. These landslide characteristics are determined primarily on the basis of geomorphic features, or landforms, observed for each landslide. This work was completed as part of the Master's thesis "Turbidity Monitoring and LiDAR Imagery Indicate Landslides are Primary Source of Suspended-Sediment Load in the Little North Santiam River Basin, Oregon, Winter 2009-2010" by Steven Sobieszczyk, Portland State University and U.S. Geological Survey.Data layers in this geodatabase include: landslide deposit boundaries (Deposits); field-verfied location imagery (Photos); head scarp or scarp flanks (Scarp_Flanks); and secondary scarp features (Scarps).The geodatabase template was developed by the Oregon Department of Geology and Mineral Industries (Burns and Madin, 2009).
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Clayey landslide initiation and acceleration strongly modulated by soil swelling
Schulz, William; Smith, Joel B.; Wang, Gonghui; Jiang, Yao; Roering, Joshua J.
2018-01-01
Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poorly with landslide reactivation and speed. In situ and laboratory measurements strongly suggested that variable pressure along the landslide's lateral shear boundaries resulting from seasonal soil expansion and contraction modulated its reactivation and speed. Slope-stability modeling suggested that the landslide's observed behavior could be predicted by including transient swell pressure as a resistance term, whereas modeling considering only transient hydrologic conditions predicted movement 5–6 months prior to when it was observed. All clayey soils swell to some degree; hence, our findings suggest that swell pressure likely modulates motion of many landslides and should be considered to improve forecasts of clayey landslide initiation and mobility.
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Costs and deaths of landslides in Europe
Haque, Ubydul; Blum, Philipp
2016-04-01
Landslides cause human and large economic losses worldwide and also in Europe. However, the quantification of associated costs and deaths is highly underestimated and still incomplete, thus the estimation of landslide costs and risk is still rather ambitious. Hence, in this study a spatio-temporal analysis of fatal landslides is presented for 27 European countries from 1995-2014. These landslides are mainly concentrated in mountainous areas. A total of 1370 fatalities are reported resulting from 476 landslides. The highest fatalities with 335 are observed in Turkey. In general, an increasing trend of fatal landslides is recognized starting in 2008. The latter is almost certainly triggered by an increase in natural extreme events such as storms (i.e. heavy rainfall) and floods. The highest annual economic loss is observed in Italy with 3.9 billion Euro per year. In contrast, in Germany the annual total loss is only about 0.3 billion Euro. The results of this study serves as an initial baseline information for further risk studies integrating landslide locations, local land use data, cost data, and will therefore certainly support the studied countries to better protect their citizens and assets. Acknowledgements We would like to acknowledge the valuable contributions by Paula F. da Silva, Peter Andersen, Jürgen Pilz, Ali Ardalan, Sergey R. Chalov, Jean-Philippe Malet, Mateja Jemec Auflič, Norina Andres, Eleftheria Poyiadji, Pedro C. Lamas, Wenyi Zhang, Igor Pesevski, Halldór G. Pétursson, Tayfun Kurt, Nikolai Dobrev, Juan Carlos García Davalillo, Matina Halkia, Stefano Ferri, George Gaprindashvili, Johanna Engström and David Keellings.
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The paleo-climate change of Chaidam Basin during the last 2.85 Ma recorded by gamma-ray logging
International Nuclear Information System (INIS)
Chen Ye; Yuan Linwang; Liu Zechun
2000-01-01
The author deals with mainly the aspect of paleo-climate change of the basin. The approach used for the study consisted of (1) establishing the paleo-climate curve of the basin according to the climate indices, including the spore-pollen statistics, carbonate content and δ 18 O, obtained from the samples of the 760 m continuously-cored exploration holes sited in the basin, (2) comparing the paleo-climate curve with the natural gamma-logs of the same exploration holes, and (3) determining the paleo-climatic changes in the last 2.85 Ma on the basis of detailed geochronological calculations. These results are extremely important for comparison with the δ 18 O-based climate curve derived from the ODP659 in the Atlantic Ocean and with the cycles of paleosol in the Chinese loess
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Effects of Inventory Bias on Landslide Susceptibility Calculations
Stanley, T. A.; Kirschbaum, D. B.
2017-01-01
Many landslide inventories are known to be biased, especially inventories for large regions such as Oregon's SLIDO or NASA's Global Landslide Catalog. These biases must affect the results of empirically derived susceptibility models to some degree. We evaluated the strength of the susceptibility model distortion from postulated biases by truncating an unbiased inventory. We generated a synthetic inventory from an existing landslide susceptibility map of Oregon, then removed landslides from this inventory to simulate the effects of reporting biases likely to affect inventories in this region, namely population and infrastructure effects. Logistic regression models were fitted to the modified inventories. Then the process of biasing a susceptibility model was repeated with SLIDO data. We evaluated each susceptibility model with qualitative and quantitative methods. Results suggest that the effects of landslide inventory bias on empirical models should not be ignored, even if those models are, in some cases, useful. We suggest fitting models in well-documented areas and extrapolating across the study region as a possible approach to modeling landslide susceptibility with heavily biased inventories.
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Investigation of relationship between sediment yield and landslide in Iran
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Samad Shadfar
2012-07-01
Full Text Available Landslides have been made irreversible damage to urban areas and economic in Iran. In this research, at first, for Investigation of relationship between landslide and sediment yield was recognized some of effective factors on Landslide. These Factors were processed with use of ILWIS and Arc GIS software’s. Landslide hazard zonation was done using Density Area and Index Overlay methods in GIS and evaluated them using Quality Sum index. In after phase, were determined sediment yield in each of them. Finally, occurrence rate landslide investigated in sediment yield zones. The results indicated that, slope, lithology and distance from the hydrographic network have the greatest impact on landslides. Most of the landslides have occurred in the 15-40% slope class, units of conglomerate and marl, and within one km of drainage network. On the other hand, the relationship between landslide frequency and distance of the fault was not a linear relationship and Almost 60 %of landslides have occurred distance of one km of the faults. Evaluation using Quality Sum index showed that the density Area has a more logical answer and as Appropriate method will be introduced in the basin. Investigation of deposition potential in sub-basins showed that Javaherdeh sub basin with 92.74 deposition potential is the first priority. Nedasht and latmohalleh sub basins, each with a deposition potential of 20.08 are the next priorities. Relationship between landslide area and deposition potential were identified as 8/91% of the landslides in the area of low And about 79 percent of landslides are located in high and very high deposition potentials.
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Paleo-event data standards for dendrochronology
Elaine Kennedy Sutherland; P. Brewer; W. Gross
2017-01-01
Extreme environmental events, such as storm winds, landslides, insect infestations, and wildfire, cause loss of life, resources, and human infrastructure. Disaster riskreduction analysis can be improved with information about past frequency, intensity, and spatial patterns of extreme events. Tree-ring analyses can provide such information: tree rings reflect events as...
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Distributed modelling of shallow landslides triggered by intense rainfall
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G. B. Crosta
2003-01-01
Full Text Available Hazard assessment of shallow landslides represents an important aspect of land management in mountainous areas. Among all the methods proposed in the literature, physically based methods are the only ones that explicitly includes the dynamic factors that control landslide triggering (rainfall pattern, land-use. For this reason, they allow forecasting both the temporal and the spatial distribution of shallow landslides. Physically based methods for shallow landslides are based on the coupling of the infinite slope stability analysis with hydrological models. Three different grid-based distributed hydrological models are presented in this paper: a steady state model, a transient "piston-flow" wetting front model, and a transient diffusive model. A comparative test of these models was performed to simulate landslide occurred during a rainfall event (27–28 June 1997 that triggered hundreds of shallow landslides within Lecco province (central Southern Alps, Italy. In order to test the potential for a completely distributed model for rainfall-triggered landslides, radar detected rainfall intensity has been used. A new procedure for quantitative evaluation of distributed model performance is presented and used in this paper. The diffusive model results in the best model for the simulation of shallow landslide triggering after a rainfall event like the one that we have analysed. Finally, radar data available for the June 1997 event permitted greatly improving the simulation. In particular, radar data allowed to explain the non-uniform distribution of landslides within the study area.
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Geomorphological mapping of shallow landslides using UAVs
Fiorucci, Federica; Giordan, Daniele; Dutto, Furio; Rossi, Mauro; Guzzetti, Fausto
2015-04-01
The mapping of event shallow landslides is a critical activity, due to the large number of phenomena, mostly with small dimension, affecting extensive areas. This is commonly done through aerial photo-interpretation or through field surveys. Nowadays, landslide maps can be realized exploiting other methods/technologies: (i) airborne LiDARs, (ii) stereoscopic satellite images, and (iii) unmanned aerial vehicles (UAVs). In addition to the landslide maps, these methods/technologies allow the generation of updated Digital Terrain Models (DTM). In December 2013, in the Collazzone area (Umbria, Central Italy), an intense rainfall event triggered a large number of shallow landslides. To map the landslides occurred in the area, we exploited data and images obtained through (A) an airborne LiDAR survey, (B) a remote controlled optocopter (equipped with a Canon EOS M) survey, and (C) a stereoscopic satellite WorldView II MS. To evaluate the mapping accuracy of these methods, we select two landslides and we mapped them using a GPS RTK instrumentation. We consider the GPS survey as the benchmark being the most accurate system. The results of the comparison allow to highlight pros and cons of the methods/technologies used. LiDAR can be considered the most accurate system and in addition it allows the extraction and the classification of the digital surface models from the surveyed point cloud. Conversely, LiDAR requires additional time for the flight planning, and specific data analysis user capabilities. The analysis of the satellite WorldView II MS images facilitates the landslide mapping over large areas, but at the expenses of a minor resolution to detect the smaller landslides and their boundaries. UAVs can be considered the cheapest and fastest solution for the acquisition of high resolution ortho-photographs on limited areas, and the best solution for a multi-temporal analysis of specific landslide phenomena. Limitations are due to (i) the needs of optimal climatic
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Floristic and vegetation successional processes within landslides in a Mediterranean environment.
Neto, Carlos; Cardigos, Patrícia; Oliveira, Sérgio Cruz; Zêzere, José Luís
2017-01-01
Floristic and vegetation analysis in seven Mediterranean landslides led to the understanding of the successional processes occurring in different landslide disturbed sectors. Our study showed that in landslides that occurred between 1996 and 2010 there is a clear differentiation between the three main landslide sectors (scarp, main body and foot) concerning floristic composition, vegetation structure, floristic richness, successional processes and plant functional type. Additional differences were found between landslide areas and undisturbed agricultural areas adjacent to landslides. In this study 48 floristic relevés were made using a stratified random sampling design. The main landslide body exhibits the highest floristic richness whereas the landslide scarp has the lowest coverage rate and the highest presence of characteristic species from ruderal and strongly perturbed habitats. Finally, the landslide foot shows a late stage in the succession (maquis or pre-forest stage) with a high dominance of vines. We further discuss the importance of landslides as reservoirs of biodiversity especially for Mediterranean orchids. Copyright © 2016 Elsevier B.V. All rights reserved.
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Landslide tsunami hazard in the Indonesian Sunda Arc
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S. Brune
2010-03-01
Full Text Available The Indonesian archipelago is known for the occurrence of catastrophic earthquake-generated tsunamis along the Sunda Arc. The tsunami hazard associated with submarine landslides however has not been fully addressed. In this paper, we compile the known tsunamigenic events where landslide involvement is certain and summarize the properties of published landslides that were identified with geophysical methods. We depict novel mass movements, found in newly available bathymetry, and determine their key parameters. Using numerical modeling, we compute possible tsunami scenarios. Furthermore, we propose a way of identifying landslide tsunamis using an array of few buoys with bottom pressure units.
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Landslide Caused Damages in a Gallery
Poisel, R.; Mair am Tinkhof, K.; Preh, A.
2016-06-01
On October 5th, 2010, cracks were found in a gallery 1.8 m high and 1.4 m wide. The gallery is 100 years old, runs parallel to a valley flank and was excavated in a tectonically strongly stressed, weathered and slightly dipping sandwich of clayey shales, sandstones and marls. The cracks in the roof as well as in the invert ran parallel to the axis of the gallery. Monitoring showed that crack widths were increasing 1.5 mm per year, sidewall distances were increasing 3.5 mm per year, whereas the height of the gallery was decreasing 2.5 mm per year. After eliminating several possible causes of cracking, a landslide producing the damages had to be taken into consideration. Monitoring of the valley flank surface as well as inclinometer readings revealed that a landslide was occurring, loading the gallery lining. Most probably the landslide had been reactivated by excessive rainfall in 2009 as well as by works for the renewal of a weir in the valley bottom. As stabilization of the slope was not an option for several reasons, it was decided to replace the gallery by a new one deeper inside the slope, which will be ready for operation in 2017. Thus the old gallery has to be kept in operation till then and it was decided to reinforce the old gallery by a heavily reinforced shotcrete lining 10 cm thick. As slope displacements went on, cracks in the shotcrete lining developed with a completely different pattern: in the section where the gallery lies completely in the landslide shear zone no cracks formed until now due to heavy reinforcement, whereas in the transition sections stable ground-landslide and landslide-stable ground diagonal tension cracks in the roof due to shear by the landslide developed. Numerical models showed that cracking and spalling of the shotcrete lining would occur only after some centimetres of additional displacements of the slope, which hopefully will not occur before 2017.
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Landslides along Highways: GIS-based Inventory and Planning Issues
Jaeger, Ann-Kathrin; Klose, Martin; Damm, Bodo
2015-04-01
Highways rank as critical transportation infrastructures that are at risk of landslides in many areas worldwide (e.g., Hungr et al., 1999; Bhandary et al., 2013). Safe and affordable operations of traffic routes constitute the two main criteria for transportation planning in landslide-prone terrain. A right balancing of these often conflicting priorities requires profound knowledge of landslide locations across highway networks and the costs caused by landslides in the past (e.g., Saha et al., 2005). Much of the direct costs affecting transportation departments relate to capital investments for landslide repair or mitigation and operational expenditures in connection with maintenance works. A systematic collection and inventory of such data sets combined with an acquisition of hazard information on vulnerable road sections is still rarely the case in engineering practice. This is despite significant cost impacts and budgetary burdens, especially in peripheral mountain areas where financial resources are naturally limited (e.g., Klose et al., 2014). The present contribution introduces a regional inventory of landslides along highways in the Harz Mountains, NW Germany. As subset of a landslide database for the entire country, this focused GIS-based inventory has been compiled in close collaboration with the Lower Saxony Department of Transportation. The inventory includes data sets gathered by archive studies and relies on high-quality information sources such as maintenance protocols, geotechnical reports, and documents from tendering, controlling, and accounting. A mapping tool in ArcGIS format is used to specify and visualize road sections affected by landslides. This spatial information on hazard exposure is complemented by narrative risk profiles for landslide sites showing a long history of damage events. By summarizing the occurrence dates of landslides, the associated damages, and the types and costs of repair or prevention, such risk profiles are useful to
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Global Landslide Total Economic Loss Risk Deciles
National Aeronautics and Space Administration — Global Landslide Total Economic Loss Risk Deciles is a 2.5 minute grid of global landslide total economic loss risks. A process of spatially allocating Gross...
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Directory of Open Access Journals (Sweden)
Yueming Yang
2016-12-01
Full Text Available Great breakthrough recently achieved in the Sinian–Lower Paleozoic gas exploration in the Leshan–Longnüsi paleo-uplift, Sichuan Basin, has also made a common view reached, i.e., large-scale paleo-uplifts will be the most potential gas exploration target in the deep strata of this basin. Apart from the above-mentioned one, the other huge paleo-uplifts are all considered to be the ones formed in the post-Caledonian period, the impact of which, however, has rarely ever been discussed on the Sinian–Lower Paleozoic oil and gas reservoir formation. In view of this, based on outcrops, drilling and geophysical data, we analyzed the Sinian–Lower Paleozoic tectonic setting and sedimentary background in the East Sichuan Basin, studied the distribution rules of reservoirs and source rocks under the control of paleo-uplifts, and finally discussed, on the basis of structural evolution analysis, the conditions for the formation of Sinian–Lower Paleozoic gas reservoirs in this study area. The following findings were achieved. (1 The Dazhou–Kaijiang inherited uplift in NE Sichuan Basin which was developed before the Middle Cambrian controlled a large area of Sinian and Cambrian beach-facies development. (2 Beach-facies reservoirs were developed in the upper part of the paleo-uplift, while in the peripheral depression belts thick source rocks were developed like the Upper Sinian Doushantuo Fm and Lower Cambrian Qiongzhusi Fm, so there is a good source–reservoir assemblage. (3 Since the Permian epoch, the Dazhou–Kaijiang paleo-uplift had gradually become elevated from the slope zone, where the Permian oil generation peak occurred in the slope or lower and gentle uplift belts, while the Triassic gas generation peak occurred in the higher uplift belts, both with a favorable condition for hydrocarbon accumulation. (4 The lower structural layers, including the Lower Cambrian and its underlying strata, in the East Sichuan Basin, are now equipped with a
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van der Meer, Douwe G.
2017-01-01
In this thesis, I aimed at searching for new ways of constraining paleo-geographic, -atmosphere and -sea level reconstructions, through an extensive investigation of mantle structure in seismic tomographic models. To this end, I explored evidence for paleo-subduction in these models and how this may
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Modeling tsunamis induced by retrogressive submarine landslides
Løvholt, F.; Kim, J.; Harbitz, C. B.
2015-12-01
Enormous submarine landslides having volumes up to thousands of km3 and long run-out may cause tsunamis with widespread effects. Clay-rich landslides, such as Trænadjupet and Storegga offshore Norway commonly involve retrogressive mass and momentum release mechanisms that affect the tsunami generation. Therefore, such landslides may involve a large amount of smaller blocks. As a consequence, the failure mechanisms and release rate of the individual blocks are of importance for the tsunami generation. Previous attempts to model the tsunami generation due to retrogressive landslides are few, and limited to idealized conditions. Here, we review the basic effects of retrogression on tsunamigenesis in simple geometries. To this end, two different methods are employed for the landslide motion, a series block with pre-scribed time lags and kinematics, and a dynamic retrogressive model where the inter-block time lag is determined by the model. The effect of parameters such as time lag on wave-height, wave-length, and dispersion are discussed. Finally, we discuss how the retrogressive effects may have influenced the tsunamis due to large landslides such as the Storegga slide. The research leading to these results has received funding from the Research Council of Norway under grant number 231252 (Project TsunamiLand) and the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement 603839 (Project ASTARTE).
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Enriching Great Britain's National Landslide Database by searching newspaper archives
Taylor, Faith E.; Malamud, Bruce D.; Freeborough, Katy; Demeritt, David
2015-11-01
Our understanding of where landslide hazard and impact will be greatest is largely based on our knowledge of past events. Here, we present a method to supplement existing records of landslides in Great Britain by searching an electronic archive of regional newspapers. In Great Britain, the British Geological Survey (BGS) is responsible for updating and maintaining records of landslide events and their impacts in the National Landslide Database (NLD). The NLD contains records of more than 16,500 landslide events in Great Britain. Data sources for the NLD include field surveys, academic articles, grey literature, news, public reports and, since 2012, social media. We aim to supplement the richness of the NLD by (i) identifying additional landslide events, (ii) acting as an additional source of confirmation of events existing in the NLD and (iii) adding more detail to existing database entries. This is done by systematically searching the Nexis UK digital archive of 568 regional newspapers published in the UK. In this paper, we construct a robust Boolean search criterion by experimenting with landslide terminology for four training periods. We then apply this search to all articles published in 2006 and 2012. This resulted in the addition of 111 records of landslide events to the NLD over the 2 years investigated (2006 and 2012). We also find that we were able to obtain information about landslide impact for 60-90% of landslide events identified from newspaper articles. Spatial and temporal patterns of additional landslides identified from newspaper articles are broadly in line with those existing in the NLD, confirming that the NLD is a representative sample of landsliding in Great Britain. This method could now be applied to more time periods and/or other hazards to add richness to databases and thus improve our ability to forecast future events based on records of past events.
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Spatio-Temporal Distribution of Landslides in Java and the Triggering Factors
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Danang Sri Hadmoko
2017-07-01
Full Text Available Java Island, the most populated island of Indonesia, is prone to landslide disasters. Their occurrence and impact have increased mainly as the result of natural factors, aggravated by human imprint. This paper is intended to analyse: (1 the spatio-temporal variation of landslides in Java during short term and long-term periods, and (2 their causative factors such as rainfall, topography, geology, earthquakes, and land-use. The evaluation spatially and temporally of historical landslides and consequences were based on the landslide database covering the period of 1981 – 2007 in the GIS environment. Database showed that landslides distributed unevenly between West Java (67 %, Central Java (29 % and East Java (4 %. Slope failures were most abundant on the very intensively weathered zone of old volcanic materials on slope angles of 30O – 40O. Rainfall threshold analysis showed that shallow landslides and deep-seated landslides were triggered by rainfall events of 300 – 600 mm and > 600 mm respectively of antecedent rainfall during 30 consecutive days, and many cases showed that the landslides were not always initiated by intense rainfall during the landslide day. Human interference plays an important role in landslide occurrence through land conversion from natural forest to dryland agriculture which was the host of most of landslides in Java. These results and methods can be used as valuable information on the spatio-temporal characteristics of landslides in Java and their relationship with causative factors, thereby providing a sound basis for landslide investigation in more detail.
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Modeling landslide recurrence in Seattle, Washington, USA
Salciarini, Diana; Godt, Jonathan W.; Savage, William Z.; Baum, Rex L.; Conversini, Pietro
2008-01-01
To manage the hazard associated with shallow landslides, decision makers need an understanding of where and when landslides may occur. A variety of approaches have been used to estimate the hazard from shallow, rainfall-triggered landslides, such as empirical rainfall threshold methods or probabilistic methods based on historical records. The wide availability of Geographic Information Systems (GIS) and digital topographic data has led to the development of analytic methods for landslide hazard estimation that couple steady-state hydrological models with slope stability calculations. Because these methods typically neglect the transient effects of infiltration on slope stability, results cannot be linked with historical or forecasted rainfall sequences. Estimates of the frequency of conditions likely to cause landslides are critical for quantitative risk and hazard assessments. We present results to demonstrate how a transient infiltration model coupled with an infinite slope stability calculation may be used to assess shallow landslide frequency in the City of Seattle, Washington, USA. A module called CRF (Critical RainFall) for estimating deterministic rainfall thresholds has been integrated in the TRIGRS (Transient Rainfall Infiltration and Grid-based Slope-Stability) model that combines a transient, one-dimensional analytic solution for pore-pressure response to rainfall infiltration with an infinite slope stability calculation. Input data for the extended model include topographic slope, colluvial thickness, initial water-table depth, material properties, and rainfall durations. This approach is combined with a statistical treatment of rainfall using a GEV (General Extreme Value) probabilistic distribution to produce maps showing the shallow landslide recurrence induced, on a spatially distributed basis, as a function of rainfall duration and hillslope characteristics.
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Adjustment of the problems of landslide GIS data
Uchiyama, S.; Doshida, S.; Oyagi, N.; Shimizu, F.; Inokuchi, T.
2012-12-01
Information on the distribution of landslides is a basic type of data used by countries for disaster prevention. Since 1972, 1:50,000 landslide maps have been produced at the Japanese National Research Institute for Earth Science and Disaster Prevention. From October 2000, the institute has been producing landslide GIS data and transmitting these data over the web. The area that has been published so far covers over 80% of Japan. Presently, the number of diagrams printed are 980 (March 2012). In addition, 350,000 landslide GIS data graphs have been digitized with the same diagrams as a base. Twelve years have passed since this GIS data acquisition program was launched, and in that time, several problems have been identified. These problems are listed below. 1) Scarps do not become polygonized. 2) Landslides which extend over the boundaries of the printed graphs are divided into separate elements. 3) When the time taken to read and interpret the landslide data differs, the shape of the landslides can vary between diagrams. 4) There have been cases of inaccurate positions and shapes in landslide GIS data produced since 2005. 5) Obvious mistakes are present in the attribute data. The causes of such problems are as follows: 1) Lack of technical examination at the time of the start of the production of the landslide GIS data. 2) Limitations of the landslide GIS data editing systems which were developed separately. 3) Program bugs which occur during the conversion of information input to an individual editing system into general-purpose GIS data. 4) Problems which arise during the process of the production of landslide GIS data. This project at the National Research Institute for Earth Science and Disaster Prevention is planned to be completed in 2013. By the end of the project, we hope to present a catalogue of all identified problems and formulate a plan to resolve them, and pass them on to the next generation.; Problems: For the diagram, scarps are presented by
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Paleo magnetism of the Ceara-Mirim dyke swarm, Northeastern Brazil
International Nuclear Information System (INIS)
Ernesto, M.; Furtado, M.H.; Martins, G.; Macedo, J.W.P.
1991-01-01
The Mesozoic tholeiitic Ceara-Mirim dyke swarm has a general east-west trend cutting the Precambrian basement of northeastern Brazil. The dykes occur mainly in the State of Rio Grande do Norte (RN) but enter the neighbouring State of Ceara to the west where they trend SW-NE. Available K-Ar radiometric dates vary between 214 and 216 Ma. HORN et al. (1988) used a procedure which allowed the removal of argon-loss effects to conclude that the ages might be situated between Middle Jurassic and Early Cretaceous. Paleo magnetic data suggest that the emplacement of the sub-swarms was not simultaneous since they show distinct magnetization directions. New paleo magnetic results that confirm the above conclusion are presented here for the western part of the swarm, where the dykes show a SW-NE structural orientation. (author)
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Soil and biomass carbon re-accumulation after landslide disturbances
Schomakers, Jasmin; Jien, Shih-Hao; Lee, Tsung-Yu; Huang-Chuan, Jr.; Hseu, Zeng-Yei; Lin, Zan Liang; Lee, Li-Chin; Hein, Thomas; Mentler, Axel; Zehetner, Franz
2017-07-01
In high-standing islands of the Western Pacific, typhoon-triggered landslides occasionally strip parts of the landscape of its vegetative cover and soil layer and export large amounts of biomass and soil organic carbon (OC) from land to the ocean. After such disturbances, new vegetation colonizes the landslide scars and OC starts to re-accumulate. In the subtropical mountains of Taiwan and in other parts of the world, bamboo (Bambusoideae) species may invade at a certain point in the succession of recovering landslide scars. Bamboo has a high potential for carbon sequestration because of its fast growth and dense rooting system. However, it is still largely unknown how these properties translate into soil OC re-accumulation rates after landslide disturbance. In this study, a chronosequence was established on four former landslide scars in the Central Mountain Range of Taiwan, ranging in age from 6 to 41 years post disturbance as determined by landslide mapping from remote sensing. The younger landslide scars were colonized by Miscanthus floridulus, while after approx. 15 to 20 years of succession, bamboo species (Phyllostachys) were dominating. Biomass and soil OC stocks were measured on the recovering landslide scars and compared to an undisturbed Cryptomeria japonica forest stand in the area. After initially slow re-vegetation, biomass carbon accumulated in Miscanthus stands with mean annual accretion rates of 2 ± 0.5 Mg C ha- 1 yr- 1. Biomass carbon continued to increase after bamboo invasion and reached 40% of that in the reference forest site after 41 years of landslide recovery. Soil OC accumulation rates were 2.0 Mg C ha- 1 yr- 1, 6 to 41 years post disturbance reaching 64% of the level in the reference forest. Our results from this in-situ study suggest that recovering landslide scars are strong carbon sinks once an initial lag period of vegetation re-establishment is overcome.
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Hu, X.; Lu, Z.; Pierson, T. C.; Kramer, R.
2017-12-01
Understanding the precipitation triggering mechanism and quantifying the creeping landslide thickness are important to conduct early warnings and estimate potential failure volume and runout extent. However, it is problematic to use traditional geodetic methods to identify the active landslide boundaries and capture the transient mobility over hilly and vegetated landslide landscape. Here we present a novel InSAR processing strategy to characterize the spatial distribution and temporal behavior of the landslide movement in response to precipitation over Crescent lake landslide, WA using spaceborne SAR data of ALOS-1 PALSAR-1, ALOS-2 PALSAR-2 and Sentinel-1A. Time-series measurements reveal the seasonal deformation of landslide lobe, showing a much larger magnitude compared to the motion at lower elevated terrain expressed by an off-slide GPS station, suggesting an amplified hydrological loading effect associated with thick unconsolidated zone. Thanks to the high temporal resolution of Sentinel-1A and on-slide GPS data, we capture the progressive incipient motions in the wet season, characterized by the elastic slope-normal contraction due to loading during antecedent rainfall, followed by downslope slip and lateral propagation in less than one-month intense precipitation, because the elevated pore pressure and the reduced friction at the basal instigate the shear motion. The proposed threshold precipitation concept, in terms of the intensity and duration, can be an integral part of the landslide warning system. The active thickness can be inverted using three-dimensional (3D) displacement map based on the principle of mass conservation. We extract quasi-3D displacements using two independent (ascending and descending) InSAR measurements assuming that the targets move exclusively along the aspect direction on the slope-parallel plane. This routine of the extraction of quasi-3D displacement and the inversion of active lobe thickness can be utilized in the study of
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Plugs or flood-makers? the unstable landslide dams of eastern Oregon
Safran, Elizabeth B.; O'Connor, Jim E.; Ely, Lisa L.; House, P. Kyle; Grant, Gordon E.; Harrity, Kelsey; Croall, Kelsey; Jones, Emily
2015-01-01
Landslides into valley bottoms can affect longitudinal profiles of rivers, thereby influencing landscape evolution through base-level changes. Large landslides can hinder river incision by temporarily damming rivers, but catastrophic failure of landslide dams may generate large floods that could promote incision. Dam stability therefore strongly modulates the effects of landslide dams and might be expected to vary among geologic settings. Here, we investigate the morphometry, stability, and effects on adjacent channel profiles of 17 former and current landslide dams in eastern Oregon. Data on landslide dam dimensions, former impoundment size, and longitudinal profile form were obtained from digital elevation data constrained by field observations and aerial imagery; while evidence for catastrophic dam breaching was assessed in the field. The dry, primarily extensional terrain of low-gradient volcanic tablelands and basins contrasts with the tectonically active, mountainous landscapes more commonly associated with large landslides. All but one of the eastern Oregon landslide dams are ancient (likely of order 103 to 104 years old), and all but one has been breached. The portions of the Oregon landslide dams blocking channels are small relative to the area of their source landslide complexes (0.4–33.6 km2). The multipronged landslides in eastern Oregon produce marginally smaller volume dams but affect much larger channels and impound more water than do landslide dams in mountainous settings. As a result, at least 14 of the 17 (82%) large landslide dams in our study area appear to have failed cataclysmically, producing large downstream floods now marked by boulder outwash, compared to a 40–70% failure rate for landslide dams in steep mountain environments. Morphometric indices of landslide dam stability calibrated in other environments were applied to the Oregon dams. Threshold values of the Blockage and Dimensionless Blockage Indices calibrated to worldwide
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Great landslide events in Italian artificial reservoirs
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A. Panizzo
2005-01-01
Full Text Available The empirical formulations to forecast landslide generated water waves, recently defined in the framework of a research program funded by the Italian National Dam Office RID (Registro Italiano Dighe, are here used to study three real cases of subaerial landslides which fell down italian artificial reservoirs. It is well known that impulse water waves generated by landslides constitute a very dangerous menace for human communities living in the shoreline of the artificial basin or downstream the dam. In 1963, the menace became tragedy, when a 270 millions m3 landslide fell down the Vajont reservoir (Italy, generated an impulse wave which destroyed the city of Longarone, and killed 2000 people. The paper is aimed at presenting the very satisfactorily reproduction of the events at hand by using forecasting formulations.
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Great landslide events in Italian artificial reservoirs
Panizzo, A.; de Girolamo, P.; di Risio, M.; Maistri, A.; Petaccia, A.
2005-09-01
The empirical formulations to forecast landslide generated water waves, recently defined in the framework of a research program funded by the Italian National Dam Office RID (Registro Italiano Dighe), are here used to study three real cases of subaerial landslides which fell down italian artificial reservoirs. It is well known that impulse water waves generated by landslides constitute a very dangerous menace for human communities living in the shoreline of the artificial basin or downstream the dam. In 1963, the menace became tragedy, when a 270 millions m3 landslide fell down the Vajont reservoir (Italy), generated an impulse wave which destroyed the city of Longarone, and killed 2000 people. The paper is aimed at presenting the very satisfactorily reproduction of the events at hand by using forecasting formulations.
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Hibert, C.; Stark, C. P.; Ekstrom, G.
2014-12-01
Landslide failures on the scale of mountains are spectacular, dangerous, and spontaneous, making direct observations hard to obtain. Measurement of their dynamic properties during runout is a high research priority, but a logistical and technical challenge. Seismology has begun to help in several important ways. Taking advantage of broadband seismic stations, recent advances now allow: (i) the seismic detection and location of large landslides in near-real-time, even for events in very remote areas that may have remain undetected, such as the 2014 Mt La Perouse supraglacial failure in Alaska; (ii) inversion of long-period waves generated by large landslides to yield an estimate of the forces imparted by the bulk accelerating mass; (iii) inference of the landslide mass, its center-of-mass velocity over time, and its trajectory.Key questions persist, such as: What can the short-period seismic data tell us about the high-frequency impacts taking place within the granular flow and along its boundaries with the underlying bedrock? And how does this seismicity relate to the bulk acceleration of the landslide and the long-period seismicity generated by it?Our recent work on the joint analysis of short- and long-period seismic signals generated by past and recent events, such as the Bingham Canyon Mine and the Oso-Steelhead landslides, provides new insights to tackle these issues. Qualitative comparison between short-period signal features and kinematic parameters inferred from long-period surface wave inversion helps to refine interpretation of the source dynamics and to understand the different mechanisms for the origin of the short-period wave radiation. Our new results also suggest that quantitative relationships can be derived from this joint analysis, in particular between the short-period seismic signal envelope and the inferred momentum of the center-of-mass. In the future, these quantitative relationships may help to constrain and calibrate parameters used in
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Application of a complex assessment of landslide hazards in mountain regions
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Kateryna E. Boyko
2017-09-01
Full Text Available The main regional factors of occurrence and activation of landslides within the mountain region were examined. As a result of study of recommendations made by experts, geologists, and gap analysis of existing methods of forecasting the landslide process, an algorithm of comprehensive assessment of landslide hazard areas based on the construction of models in a GIS environment was proposed. These models describe the spatial patterns of landslides. All factors determining the tendency of the studies area to the landslide process development were divided into actual factors, reflecting the regional peculiarities of the territory and forming the landslide-prone slopes (static model, as well as triggering factors, initiating the landslide process and determining its activity (dynamic model. The first cartographic model was built, showing the distribution of the deterministic indirect indicator of landslide hazard, i.e. stability index.
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Topographic signatures of deep-seated landslides and a general landscape evolution model
Booth, A. M.; Roering, J. J.; Rempel, A. W.
2012-12-01
A fundamental goal of studying earth surface processes is to disentangle the complex web of interactions among baselevel, climate, and rock properties that generate characteristic landforms. Mechanistic geomorphic transport laws can quantitatively address this goal, but no widely accepted law for landslides exists. Here, we propose a transport law for deep-seated landslides and demonstrate its utility using a two-dimensional numerical landscape evolution model informed by study areas in the Waipaoa catchment, New Zealand and the Eel River catchment, California. We define a non-dimensional landslide number, which is the ratio of uplift to landslide flow time scales, that predicts three distinct landscape types. The first is dominated by stochastic landsliding, whereby discrete landslide events episodically erode material at rates far exceeding the long term uplift rate. The second is characterized by steady landsliding, in which the landslide flux at any location remains constant through time and is largest at the steepest locations in the catchment. The third is not significantly affected by landsliding. In both the "stochastic landsliding" and "steady landsliding" regimes, increases in the non-dimensional landslide number systematically reduce catchment relief and widen valley spacing, producing long, quasi-planar, low angle hillslopes despite high uplift rates. The stochastic landsliding regime best captures the frequent observation that deep-seated landslides produce a large sediment flux from a small aerial extent while being active only a fraction of the time. We suggest that this model is adaptable to a wide range of geologic settings and may be useful for interpreting climate-driven changes in landslide behavior.
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From Physical Process to Economic Cost - Integrated Approaches of Landslide Risk Assessment
Klose, M.; Damm, B.
2014-12-01
The nature of landslides is complex in many respects, with landslide hazard and impact being dependent on a variety of factors. This obviously requires an integrated assessment for fundamental understanding of landslide risk. Integrated risk assessment, according to the approach presented in this contribution, implies combining prediction of future landslide occurrence with analysis of landslide impact in the past. A critical step for assessing landslide risk in integrated perspective is to analyze what types of landslide damage affected people and property in which way and how people contributed and responded to these damage types. In integrated risk assessment, the focus is on systematic identification and monetization of landslide damage, and analytical tools that allow deriving economic costs from physical landslide processes are at the heart of this approach. The broad spectrum of landslide types and process mechanisms as well as nonlinearity between landslide magnitude, damage intensity, and direct costs are some main factors explaining recent challenges in risk assessment. The two prevailing approaches for assessing the impact of landslides in economic terms are cost survey (ex-post) and risk analysis (ex-ante). Both approaches are able to complement each other, but yet a combination of them has not been realized so far. It is common practice today to derive landslide risk without considering landslide process-based cause-effect relationships, since integrated concepts or new modeling tools expanding conventional methods are still widely missing. The approach introduced in this contribution is based on a systematic framework that combines cost survey and GIS-based tools for hazard or cost modeling with methods to assess interactions between land use practices and landslides in historical perspective. Fundamental understanding of landslide risk also requires knowledge about the economic and fiscal relevance of landslide losses, wherefore analysis of their
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Landslide inventory along a pipeline corridor in the Mackenzie Valley, Northwest Territories
Energy Technology Data Exchange (ETDEWEB)
Couture, R.; Riopel, S. [Natural Resources Canada, Ottawa, ON (Canada). Geological Survey of Canada
2007-07-01
The route for the proposed Mackenzie Valley gas pipeline in the Northwest Territories includes areas that are known for widespread landsliding. Natural Resources Canada initiated a landslide mapping project in an effort to develop a synthesis of the types, regional distribution, and controlling factors of landslides in the region. The study area is covered by unconsolidated sediments dominated by morainal, lacustrine, and alluvial deposits. Three types of permafrost were mapped, notably continuous, extensive discontinuous, and intermediate discontinuous. A preliminary inventory of 1,807 landslides and other natural terrain hazard features were identified by air photo interpretations. The landslide limits were digitized and catalogued in the Mackenzie Valley landslide spatial database. Several attributes were recorded for each landslide feature, including unique identifiers, landslide type, size, location, morphological parameters, and relative age. The landslide distribution was then characterized. The results indicate an average density of one landslide per 5 km{sup 2}. The dominant landslide types are retrogressive thaw flows and active layer detachments, followed by rock falls, debris flows, earth slides, surficial landslides, and retrogressive thaw slides. Nearly half of all landslides took place in morainal deposits, 19 per cent in lacustrine sediments, 14 per cent in bedrock, and 13 per cent in glaciofluvial sediments. According to tone, texture, and vegetation regrowth attributes, 39 per cent of the landslides were classified as being older than 50 years, 39 per cent were 10 to 50 years old and 22 per cent were less than 10 years old.
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Basal-topographic control of stationary ponds on a continuously moving landslide
Coe, J.A.; McKenna, J.P.; Godt, J.W.; Baum, R.L.
2009-01-01
The Slumgullion landslide in the San Juan Mountains of southwestern Colorado has been moving for at least the last few hundred years and has multiple ponds on its surface. We have studied eight ponds during 30 trips to the landslide between July 1998 and July 2007. During each trip, we have made observations on the variability in pond locations and water levels, taken ground-based photographs to document pond water with respect to moving landslide material and vegetation, conducted Global Positioning System surveys of the elevations of water levels and mapped pond sediments on the landslide surface. Additionally, we have used stereo aerial photographs taken in October 1939, October 1940 and July 2000 to measure topographic profiles of the eight pond locations, as well as a longitudinal profile along the approximate centerline of the landslide, to examine topographic changes over a 60- to 61-year period of time. Results from field observations, analyses of photographs, mapping and measurements indicate that all pond locations have remained spatially stationary for 60-300 years while landslide material moves through these locations. Water levels during the observation period were sensitive to changes in the local, spring-fed, stream network, and to periodic filling of pond locations by sediment from floods, hyperconcentrated flows, mud flows and debris flows. For pond locations to remain stationary, the locations must mimic depressions along the basal surface of the landslide. The existence of such depressions indicates that the topography of the basal landslide surface is irregular. These results suggest that, for translational landslides that have moved distances larger than the dimensions of the largest basal topographic irregularities (about 200 m at Slumgullion), landslide surface morphology can be used as a guide to the morphology of the basal slip surface. Because basal slip surface morphology can affect landslide stability, kinematic models and stability
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GIS-based landslide susceptibility mapping for the 2005 Kashmir earthquake region
Kamp, Ulrich; Growley, Benjamin J.; Khattak, Ghazanfar A.; Owen, Lewis A.
2008-11-01
The Mw 7.6 October 8, 2005 Kashmir earthquake triggered several thousand landslides throughout the Himalaya of northern Pakistan and India. These were concentrated in six different geomorphic-geologic-anthropogenic settings. A spatial database, which included 2252 landslides, was developed and analyzed using ASTER satellite imagery and geographical information system (GIS) technology. A multi-criterion evaluation was applied to determine the significance of event-controlling parameters in triggering the landslides. The parameters included lithology, faults, slope gradient, slope aspect, elevation, land cover, rivers and roads. The results showed four classes of landslide susceptibility. Furthermore, they indicated that lithology had the strongest influence on landsliding, particularly when the rock is highly fractured, such as in shale, slate, clastic sediments, and limestone and dolomite. Moreover, the proximity of the landslides to faults, rivers, and roads was also an important factor in helping to initiate failures. In addition, landslides occurred particularly in moderate elevations on south facing slopes. Shrub land, grassland, and also agricultural land were highly susceptible to failures, while forested slopes had few landslides. One-third of the study area was highly or very highly susceptible to future landsliding and requires immediate mitigation action. The rest of the region had a low or moderate susceptibility to landsliding and remains relatively stable. This study supports the view that (1) earthquake-triggered landslides are concentrated in specific zones associated with event-controlling parameters; and (2) in the western Himalaya deforestation and road construction contributed significantly to landsliding during and shortly after earthquakes.
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Landslide scaling and magnitude-frequency distribution (Invited)
Stark, C. P.; Guzzetti, F.
2009-12-01
Landslide-driven erosion is controlled by the scale and frequency of slope failures and by the consequent fluxes of debris off the hillslopes. Here I focus on the magnitude-frequency part of the process and develop a theory of initial slope failure and debris mobilization that reproduces the heavy-tailed distributions (PDFs) observed for landslide source areas and volumes. Landslide rupture propagation is treated as a quasi-static, non-inertial process of simplified elastoplastic deformation with strain weakening; debris runout is not considered. The model tracks the stochastically evolving imbalance of frictional, cohesive, and body forces across a failing slope, and uses safety-factor concepts to convert the evolving imbalance into a series of incremental rupture growth or arrest probabilities. A single rupture is simulated with a sequence of weighted ``coin tosses'' with weights set by the growth probabilities. Slope failure treated in this stochastic way is a survival process that generates asymptotically power-law-tail PDFs of area and volume for rock and debris slides; predicted scaling exponents are consistent with analyses of landslide inventories. The primary control on the shape of the model PDFs is the relative importance of cohesion over friction in setting slope stability: the scaling of smaller, shallower failures, and the size of the most common landslide volumes, are the result of the low cohesion of soil and regolith, whereas the negative power-law tail scaling for larger failures is tied to the greater cohesion of bedrock. The debris budget may be dominated by small or large landslides depending on the scaling of both the PDF and of the depth-length relation. I will present new model results that confirm the hypothesis that depth-length scaling is linear. Model PDF of landslide volumes.
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What rainfall events trigger landslides on the West Coast US?
Biasutti, Michela; Seager, Richard; Kirschbaum, Dalia
2016-04-01
A dataset of landslide occurrences compiled by collating google news reports covers 9 full years of data. We show that, while this compilation cannot provide consistent and widespread monitoring everywhere, it is adequate to capture the distribution of events in the major urban areas of the West Coast US and it can be used to provide a quantitative relationship between landslides and rainfall events. The case of the Seattle metropolitan area is presented as an example. The landslide dataset shows a clear seasonality in landslide occurrence, corresponding to the seasonality of rainfall, modified by the accumulation of soil moisture as winter progresses. Interannual variability of landslide occurrences is also linked to interannual variability of monthly rainfall. In most instances, landslides are clustered on consecutive days or at least within the same pentad and correspond to days of large rainfall accumulation at the regional scale. A joint analysis of the landslide data and of the high-resolution PRISM daily rainfall accumulation shows that on days when landslides occurred, the distribution of rainfall was shifted, with rainfall accumulation higher than 10mm/day being more common. Accumulations above 50mm/day much increase the probability of landslides, including the possibility of a major landslide event (one with multiple landslides in a day). The synoptic meteorological conditions associated with these major events show a mid-tropospheric ridge to the south of the target area steering a surface low and bringing enhanced precipitable water towards the Pacific North West. The interaction of the low-level flow with the local orography results in instances of a strong Puget Sound Convergence Zone, with widespread rainfall accumulation above 30mm/day and localized maxima as high as 100mm/day or more.
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Landslide Activity Maps Generation by Means of Persistent Scatterer Interferometry
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Silvia Bianchini
2013-11-01
Full Text Available In this paper a methodology is proposed to elaborate landslide activity maps through the use of PS (Persistent Scatterer data. This is illustrated through the case study of Tramuntana Range in the island of Majorca (Spain, where ALOS (Advanced Land Observing Satellite images have been processed through a Persistent Scatterer Interferometry (PSI technique during the period of 2007–2010. The landslide activity map provides, for every monitored landslide, an assessment of the PS visibility according to the relief, land use, and satellite acquisition parameters. Landslide displacement measurements are projected along the steepest slope, in order to compare landslide velocities with different slope orientations. Additionally, a ground motion activity map is also generated, based on active PS clusters not included within any known landslide phenomenon, but even moving, potentially referred to unmapped landslides or triggered by other kinds of geomorphological processes. In the Tramuntana range, 42 landslides were identified as active, four as being potential to produce moderate damage, intersecting the road Ma-10, which represents the most important road of the island and, thus, the main element at risk. In order to attest the reliability of measured displacements to represent landslide dynamics, a confidence degree evaluation is proposed. In this test site, seven landslides exhibit a high confidence degree, medium for 93 of them, and low for 51. A low confidence degree was also attributed to 615 detected active clusters with a potential to cause moderate damage, as their mechanism of the triggering cause is unknown. From this total amount, 18 of them intersect the Ma-10, representing further potentially hazardous areas. The outcomes of this work reveal the usefulness of landslide activity maps for environmental planning activities, being exportable to other radar data and different geomorphological settings.
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Submarine Landslides: What we Know and Where we are Going!
Moscardelli, L. G.; Mountjoy, J. J.; Micallef, A.; Strasser, M.; Vanneste, M.; Chaytor, J. D.; Mosher, D.; Krastel, S.; Lo Iacono, C.; Yamada, Y.
2015-12-01
Submarine landslides and other gravity-induced movements can disrupt very large areas of continental margins resulting in long-term seafloor morphologic change and multi-scale mass transport deposits (MTDs). Potential consequences of submarine landslides include damage to seabed infrastructure, offshore facilities, as well as generation or enhancement of tsunamis. MTDs are common on the modern seafloor and within the stratigraphic record. Slides, slumps and debris flows can be constituents of MTDs and can co-occur in the same event or depositional unit. Recent research indicates that relationships exist between MTD geological setting, causal mechanisms, and geometries. Quantitative data analysis suggests that MTD morphometric parameters can be used to link these three parameters. Despite many advances in this field, it still remains unclear how to definitively identify pre-conditioning factors and triggers of submarine landslides in modern slopes, and how submarine landslides evolve after initiation. In addition, new questions regarding the interaction between submarine landslides and active marine processes, such as bottom currents and fluid flow, have emerged.One of the mandates of the S4SLIDE (IGCP-640) project, a joint endeavor of UNESCO and IGCP that represents the broad field of submarine landslide research, is to facilitate interactions at an international level among scientists, industry and government representatives to advance our knowledge on a number of outstanding science questions: (i) What is the nature of the interaction between current-controlled sedimentation and submarine landslides? (ii) What role do transient turbulent-laminar flows play in the formation of submarine landslides? (iii) Do climatic variations control the occurrence of submarine landslides? (iv) What is the economic significance of submarine landslides? (v) Do we understand the hazards that submarine landslides pose to the environment and to humans? This presentation will cover
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Czech Academy of Sciences Publication Activity Database
Raška, P.; Zábranský, V.; Brázdil, Rudolf; Lamková, J.
2016-01-01
Roč. 255, feb (2016), s. 95-107 ISSN 0169-555X Institutional support: RVO:67179843 Keywords : flysch carpathians * shallow landslides * rainfall intensity * duration control * climatic-change * central-europe * debris flows * czechia * state * Landslide reconstruction * Documentary data * Little Ice Age * North Bohemia Subject RIV: EH - Ecology, Behaviour Impact factor: 2.958, year: 2016
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Zeng, Runqiang; Meng, Xingmin; Wang, Siyuan; Chen, Guan; Lee, Yajun; Zhang, Yi
2014-05-01
The construction of three large hydropower stations, i.e. Liujia, Yanguo and Bapan, resulted in the immigration of the impacted people to Heifangtai from 1960s. To support the living and farming of the immigrated people, a large amount of water has been pumped from the Yellow River to Heifangtai, which has changed the former underground water budget and led to 111 landslides from 1968 in this area. To reveal the deformation process of landslides in Heifangtai, a quantitative deformation analysis model of landslide based on multi-source DEM data is established using four periods of topographic maps obtained in 1970, 2001, 2010 and 2013 respectively, including two 1:10000 topographic maps and two 1:1000 data acquired from 3D Laser Scanner. The whole study area was divided into two sections based on the two distinct kinds of landslide patterns. The selected morphometric parameters, residual topographic surface and surface roughness, extracted from three typical landslides, and the statistical analysis (Box-plot diagrams) of the temporal variations of these parameters, allowed the reconstruction and tracking of these landslides. We monitored the changing of landslide boundaries, average vertical and horizontal displacement rates and zones of uplift and subsidence. The volumes of removed and/or accumulated material were estimated as well. We can then demonstrate the kinematics of landslides based on information from high-resolution DEM, and the changing table of underground water, ring-shear test and soil-water characteristic curve referenced from other researchers. The results provide a new insight on the use of multi-source high resolution DEM in the monitoring of irrigation-triggered landslides.
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Microseismic Events Detection on Xishancun Landslide, Sichuan Province, China
Sheng, M.; Chu, R.; Wei, Z.
2016-12-01
On landslide, the slope movement and the fracturing of the rock mass often lead to microearthquakes, which are recorded as weak signals on seismographs. The distribution characteristics of temporal and spatial regional unstability as well as the impact of external factors on the unstable regions can be understand and analyzed by monitoring those microseismic events. Microseismic method can provide some information inside the landslide, which can be used as supplementary of geodetic methods for monitoring the movement of landslide surface. Compared to drilling on landslide, microseismic method is more economical and safe. Xishancun Landslide is located about 60km northwest of Wenchuan earthquake centroid, it keep deforming after the earthquake, which greatly increases the probability of disasters. In the autumn of 2015, 30 seismometers were deployed on the landslide for 3 months with intervals of 200 500 meters. First, we used regional earthquakes for time correction of seismometers to eliminate the influence of inaccuracy GPS clocks and the subsurface structure of stations. Due to low velocity of the loose medium, the travel time difference of microseismic events on the landslide up to 5s. According to travel time and waveform characteristics, we found many microseismic events and converted them into envelopes as templates, then we used a sliding-window cross-correlation technique based on waveform envelope to detect the other microseismic events. Consequently, 100 microseismic events were detected with the waveforms recorded on all seismometers. Based on the location, we found most of them located on the front of the landslide while the others located on the back end. The bottom and top of the landslide accumulated considerable energy and deformed largely, radiated waves could be recorded by all stations. What's more, the bottom with more events seemed very active. In addition, there were many smaller events happened in middle part of the landslide where released
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Landsliding and its multiscale influence on mountainscapes
Restrepo, C.; Walker, L.R.; Bussmann, R.; Claessens, L.
2009-01-01
Landsliding is a complex process that modifies mountainscapes worldwide. Its severe and sometimes long-lasting negative effects contrast with the less-documented positive effects on ecosystems, raising numerous questions about the dual role of landsliding, the feedbacks between biotic and geomorphic
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Development research of expert system for diagnosis of landslide
Energy Technology Data Exchange (ETDEWEB)
Yoshikawa, Toru; Soeda, Yoshio; Nakamura, Hirohisa [Kansai Electric Power Co. Inc., Osaka (Japan)
1989-03-25
Measures against landslides are based upon a judgment to be made by combined application of professional knowledge of the scientific fields such as topography and geology, etc. and Kansai Electric Power Co. tried to construct a technical support system for preliminary diagnosis of landslide with which field engineers can easily utilize expert knowledge and to which artificial intelligence (AI) is applied. This system is to diagnose preliminarily the existence of such a landslide-prone area which is likely to hamper the project concerned at its early stage and after examination, those considered to be appropriate for the purpose were selected from among the artificial intelligence tools already developed. And as the knowledge base, knowledge was arranged in order with regard to the common features of landslide-prone areas, classification of landslide spots, landslide-prone topography and confusing topography, and procedures as well as remarks to be taken in reading the landslide topography, and was transformed as rule in order to input as the knowledge base into a computer. The system used the aerial photography interpretation theory as the base for its expert knowledge base and the materials necessary therefore were confined to easily obtainable aerial photographs and topographical maps. The system was prepared with a general purpose personal computer. 4 figs., 1 tab.
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Derivation of critical rainfall thresholds for landslide in Sicily
Caracciolo, Domenico; Arnone, Elisa; Noto, Leonardo V.
2015-04-01
Rainfall is the primary trigger of shallow landslides that can cause fatalities, damage to properties and economic losses in many areas of the world. For this reason, determining the rainfall amount/intensity responsible for landslide occurrence is important, and may contribute to mitigate the related risk and save lives. Efforts have been made in different countries to investigate triggering conditions in order to define landslide-triggering rainfall thresholds. The rainfall thresholds are generally described by a functional relationship of power in terms of cumulated or intensity event rainfall-duration, whose parameters are estimated empirically from the analysis of historical rainfall events that triggered landslides. The aim of this paper is the derivation of critical rainfall thresholds for landslide occurrence in Sicily, southern Italy, by focusing particularly on the role of the antecedent wet conditions. The creation of the appropriate landslide-rainfall database likely represents one of main efforts in this type of analysis. For this work, historical landslide events occurred in Sicily from 1919 to 2001 were selected from the archive of the Sistema Informativo sulle Catastrofi Idrogeologiche, developed under the project Aree Vulnerabili Italiane. The corresponding triggering precipitations were screened from the raingauges network in Sicily, maintained by the Osservatorio delle Acque - Agenzia Regionale per i Rifiuti e le Acque. In particular, a detailed analysis was carried out to identify and reconstruct the hourly rainfall events that caused the selected landslides. A bootstrapping statistical technique has been used to determine the uncertainties associated with the threshold parameters. The rainfall thresholds at different exceedance probability levels, from 1% to 10%, were defined in terms of cumulated event rainfall, E, and rainfall duration, D. The role of rainfall prior to the damaging events was taken into account by including in the analysis
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MULTI-CRITERIA ANALYSIS APPLIED TO LANDSLIDE SUSCEPTIBILITY MAPPING
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Mariana Madruga de Brito
2017-10-01
Full Text Available This paper presents the application of a multi-criteria analysis (MCA tool for landslide susceptibility assessment in Porto Alegre municipality, southern Brazil. A knowledge driven approach was used, aiming to ensure an optimal use of the available information. The landslide conditioning factors considered were slope, lithology, flow accumulation and distance from lineaments. Standardization of these factors was done through fuzzy membership functions, and evaluation of their relative importance for landslide predisposition was supported by the analytic hierarchy process (AHP, based on local expert knowledge. Finally, factors were integrated in a GIS environment using the weighted linear combination (WLC method. For validation, an inventory, including 107 landslide points recorded between 2007 and 2013 was used. Results indicated that 8.2% (39.40 km² of the study area are highly and very highly susceptible to landslides. An overall accuracy of 95% was found, with an area under the receiver operating characteristic (ROC curve of 0.960. Therefore, the resulting map can be regarded as useful for monitoring landslide-prone areas. Based on the findings, it is concluded that the proposed method is effective for susceptibility assessment since it yielded meaningful results and does not require extensive input data.
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InSAR deformation monitoring of high risk landslides
Singhroy, V.; Li, J.
2013-05-01
During the past year there were at least twenty five media reports of landslides and seismic activities some fatal, occurring in various areas in Canada. These high risk geohazards sites requires high resolution monitoring both spatially and temporally for mitigation purposes, since they are near populated areas and energy, transportation and communication corridors. High resolution air photos, lidar and satellite images are quite common in areas where the landslides can be fatal. Radar interferometry (InSAR) techniques using images from several radar satellites are increasingly being used in slope stability assessment. This presentation provides examples of using high-resolution (1-3m) frequent revisits InSAR techniques from RADARSAT 2 and TerraSAR X to monitor several types of high-risk landslides affecting transportation and energy corridors and populated areas. We have analyses over 200 high resolution InSAR images over a three year period on geologically different landslides. The high-resolution InSAR images are effective in characterizing differential motion within these low velocity landslides. The low velocity landslides become high risk during the active wet spring periods. The wet soils are poor coherent targets and corner reflectors provide an effective means of InSAR monitoring the slope activities.
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Angulo, Rodolfo J; Giannini, Paulo C F; Souza, Maria Cristina DE; Lessa, Guilherme C
2016-01-01
The present work discusses and reinterprets paleo-sea level indicators used to build Holocene sea-level curve for the coast of Rio de Janeiro at former works. We conclude that: (a) the paleo-sea levels inferred by vermetid remains show that sea-level has fallen over the past 4400 years, at least; (b) the paleo-sea level inferred by the beachrock facies and dated shells of Jaconé shows that sea-level was near the present elevation between 8198 and 5786 years before present; and (c) several shells from other beachrocks were deposited probably thousands of years after the specimens died and consequently do not allow precise reconstructions of paleo-sea levels. These conclusions differ from the conclusions of the original paper.
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Comparison of the landslide susceptibility models in Taipei Water Source Domain, Taiwan
WU, C. Y.; Yeh, Y. C.; Chou, T. H.
2017-12-01
Taipei Water Source Domain, locating at the southeast of Taipei Metropolis, is the main source of water resource in this region. Recently, the downstream turbidity often soared significantly during the typhoon period because of the upstream landslides. The landslide susceptibilities should be analysed to assess the influence zones caused by different rainfall events, and to ensure the abilities of this domain to serve enough and quality water resource. Generally, the landslide susceptibility models can be established based on either a long-term landslide inventory or a specified landslide event. Sometimes, there is no long-term landslide inventory in some areas. Thus, the event-based landslide susceptibility models are established widely. However, the inventory-based and event-based landslide susceptibility models may result in dissimilar susceptibility maps in the same area. So the purposes of this study were to compare the landslide susceptibility maps derived from the inventory-based and event-based models, and to interpret how to select a representative event to be included in the susceptibility model. The landslide inventory from Typhoon Tim in July, 1994 and Typhoon Soudelor in August, 2015 was collected, and used to establish the inventory-based landslide susceptibility model. The landslides caused by Typhoon Nari and rainfall data were used to establish the event-based model. The results indicated the high susceptibility slope-units were located at middle upstream Nan-Shih Stream basin.
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Coulomb Mechanics And Landscape Geometry Explain Landslide Size Distribution
Jeandet, L.; Steer, P.; Lague, D.; Davy, P.
2017-12-01
It is generally observed that the dimensions of large bedrock landslides follow power-law scaling relationships. In particular, the non-cumulative frequency distribution (PDF) of bedrock landslide area is well characterized by a negative power-law above a critical size, with an exponent 2.4. However, the respective role of bedrock mechanical properties, landscape shape and triggering mechanisms on the scaling properties of landslide dimensions are still poorly understood. Yet, unravelling the factors that control this distribution is required to better estimate the total volume of landslides triggered by large earthquakes or storms. To tackle this issue, we develop a simple probabilistic 1D approach to compute the PDF of rupture depths in a given landscape. The model is applied to randomly sampled points along hillslopes of studied digital elevation models. At each point location, the model determines the range of depth and angle leading to unstable rupture planes, by applying a simple Mohr-Coulomb rupture criterion only to the rupture planes that intersect downhill surface topography. This model therefore accounts for both rock mechanical properties, friction and cohesion, and landscape shape. We show that this model leads to realistic landslide depth distribution, with a power-law arising when the number of samples is high enough. The modeled PDF of landslide size obtained for several landscapes match the ones from earthquakes-driven landslides catalogues for the same landscape. In turn, this allows us to invert landslide effective mechanical parameters, friction and cohesion, associated to those specific events, including Chi-Chi, Wenchuan, Niigata and Gorkha earthquakes. The cohesion and friction ranges (25-35 degrees and 5-20 kPa) are in good agreement with previously inverted values. Our results demonstrate that reduced complexity mechanics is efficient to model the distribution of unstable depths, and show the role of landscape variability in landslide size
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Land use change and landslide characteristics analysis for community-based disaster mitigation.
Chen, Chien-Yuan; Huang, Wen-Lin
2013-05-01
On August 8, 2009, Typhoon Morakot brought heavy rain to Taiwan, causing numerous landslides and debris flows in the Taihe village area of Meishan Township, Chiayi County, in south-central Taiwan. In the Taihe land is primary used for agriculture and land use management may be a factor in the area's landslides. This study explores Typhoon Morakot-induced landslides and land use changes between 1999 and 2009 using GIS with the aid of field investigation. Spot 5 satellite images with a resolution of 2.5 m are used for landslide interpretation and manually digitalized in GIS. A statistical analysis for landslide frequency-area distribution was used to identify the landslide characteristics associated with different types of land use. There were 243 landslides with a total area of 2.75 km(2) in the study area. The area is located in intrinsically fragile combinations of sandstone and shale. Typhoon Morakot-induced landslides show a power-law distribution in the study area. Landslides were mainly located in steep slope areas containing natural forest and in areas planted with bamboo, tea, and betel nut. Land covered with natural forest shows the highest landslide ratio, followed by bamboo, betel nut, and tea. Landslides thus show a higher ratio in areas planted with shallow root vegetation such as bamboo, betel nut, and tea. Furthermore, the degree of basin development is proportional to the landslide ratio. The results show that a change in vegetation cover results in a modified landslide area and frequency and changed land use areas have higher landslide ratios than non-changed. Land use management and community-based disaster prevention are needed in mountainous areas of Taiwan for hazard mitigation.
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Microstructures in landslides in northwest China - Implications for creeping displacements?
Schäbitz, M.; Janssen, C.; Wenk, H.-R.; Wirth, R.; Schuck, B.; Wetzel, H.-U.; Meng, X.; Dresen, G.
2018-01-01
Microstructures, mineralogical composition and texture of selected landslide samples from three landslides in the southern part of the Gansu Province (China) were examined with optical microscopy, transmission electron microscopy (TEM), x-ray diffraction (XRD) and synchrotron x-ray diffraction measurements. Common sheet silicates are chlorite, illite, muscovite, kaolinite, pyrophyllite and dickite. Other minerals are quartz, calcite, dolomite and albite. In one sample, graphite and amorphous carbon were detected by TEM-EDX analyses and TEM high-angle annular dark-field images. The occurrence of graphite and pyrophyllite with very low friction coefficients in the gouge material of the Suoertou and Xieliupo landslides is particularly significant for reducing the frictional strength of the landslides. It is proposed that the landslides underwent comparable deformation processes as fault zones. The low friction coefficients provide strong evidence that slow-moving landsliding is controlled by the presence of weak minerals. In addition, TEM observations document that grain size reduction in clayey slip zone material was produced mainly by mechanical abrasion. For calcite and quartz, grain size reduction was attributed to both pressure solution and cataclasis. Therefore, besides landslide composition, the occurrence of ultrafine-grained slip zone material may also contribute to weakening processes of landslides. TEM images of slip-zone samples show both locally aligned clay particles, as well as kinked and folded sheet silicates, which are widely disseminated in the whole matrix. Small, newly formed clay particles have random orientations. Based on synchrotron x-ray diffraction measurements, the degree of preferred orientation of constituent sheet silicates in local shear zones of the Suoertou and Duang-He-Ba landslide is strong. This work is the first reported observation of well-oriented clay fabrics in landslides.
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Landslide detection using very high-resolution satellite imageries
Suga, Yuzo; Konishi, Tomohisa
2012-10-01
The heavy rain induced by the 12th typhoon caused landslide disaster at Kii Peninsula in the middle part of Japan. We propose a quick response method for landslide disaster mapping using very high resolution (VHR) satellite imageries. Especially, Synthetic Aperture Radar (SAR) is effective because it has the capability of all weather and day/night observation. In this study, multi-temporal COSMO-SkyMed imageries were used to detect the landslide areas. It was difficult to detect the landslide areas using only backscatter change pattern derived from pre- and post-disaster COSMOSkyMed imageries. Thus, the authors adopted a correlation analysis which the moving window was selected for the correlation coefficient calculation. Low value of the correlation coefficient reflects land cover change between pre- and post-disaster imageries. This analysis is effective for the detection of landslides using SAR data. The detected landslide areas were compared with the area detected by EROS-B high resolution optical image. In addition, we have developed 3D viewing system for geospatial visualizing of the damaged area using these satellite image data with digital elevation model. The 3D viewing system has the performance of geographic measurement with respect to elevation height, area and volume calculation, and cross section drawing including landscape viewing and image layer construction using a mobile personal computer with interactive operation. As the result, it was verified that a quick response for the detection of landslide disaster at the initial stage could be effectively performed using optical and SAR very high resolution satellite data by means of 3D viewing system.
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Earthquake-induced landslide-susceptibility mapping using an artificial neural network
Directory of Open Access Journals (Sweden)
S. Lee
2006-01-01
Full Text Available The purpose of this study was to apply and verify landslide-susceptibility analysis techniques using an artificial neural network and a Geographic Information System (GIS applied to Baguio City, Philippines. The 16 July 1990 earthquake-induced landslides were studied. Landslide locations were identified from interpretation of aerial photographs and field survey, and a spatial database was constructed from topographic maps, geology, land cover and terrain mapping units. Factors that influence landslide occurrence, such as slope, aspect, curvature and distance from drainage were calculated from the topographic database. Lithology and distance from faults were derived from the geology database. Land cover was identified from the topographic database. Terrain map units were interpreted from aerial photographs. These factors were used with an artificial neural network to analyze landslide susceptibility. Each factor weight was determined by a back-propagation exercise. Landslide-susceptibility indices were calculated using the back-propagation weights, and susceptibility maps were constructed from GIS data. The susceptibility map was compared with known landslide locations and verified. The demonstrated prediction accuracy was 93.20%.
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Aerial-Photointerpretation of landslides along the Ohio and Mississippi rivers
Su, W.-J.; Stohr, C.
2000-01-01
A landslide inventory was conducted along the Ohio and Mississippi rivers in the New Madrid Seismic Zone of southern Illinois, between the towns of Olmsted and Chester, Illinois. Aerial photography and field reconnaissance identified 221 landslides of three types: rock/debris falls, block slides, and undifferentiated rotational/translational slides. Most of the landslides are small- to medium-size, ancient rotational/translational features partially ob-scured by vegetation and modified by weathering. Five imagery sources were interpreted for landslides: 1:250,000-scale side-looking airborne radar (SLAR); 1:40,000-scale, 1:20,000-scale, 1:6,000-scale, black and white aerial photography; and low altitude, oblique 35-mm color photography. Landslides were identified with three levels of confidence on the basis of distinguishing characteristics and ambiguous indicators. SLAR imagery permitted identification of a 520 hectare mega-landslide which would not have been identified on medium-scale aerial photography. The leaf-off, 35-mm color, oblique photography provided the best imagery for confident interpretation of detailed features needed for smaller landslides.
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Rainfall-threshold conditions for landslides in a humid-tropical system
Larsen, Matthew C.; Simon, Andrew
1993-01-01
Landslides are triggered by factors such as heavy rainfall, seismic activity, and construction on hillslopes. The leading cause of landslides in Puerto Rico is intense and/or prolonged rainfall. A rainfall threshold for rainfall-triggered landsliding is delimited by 256 storms that occurred between 1959 and 1991 in the central mountains of Puerto Rico, where mean annual rainfall is close to or in excess of 2,000 mm. Forty one of the 256 storms produced intense and/or prolonged rainfall that resulted in tens to hundreds of landslides. A threshold fitted to the lower boundary of the field defined by landslide-triggering storms is expressed as
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International Nuclear Information System (INIS)
Dong Tingkuan; Kang Xiuping
2001-01-01
According to the characteristics of paleo-channel sedimentary evolution in Erlian Basin, the authors investigate the geomorphological forms, regional hydrogeological conditions, the distribution of recent and paleo-stream channels and alluvial-proluvial fans, the hydrodynamic conditions of recharge-run off-discharge for phreatic water and interlayer ground water, as well as the spatial distribution of local discharge areas applying the satellite image analysis techniques. Guided by the theory of hydrogenetic uranium deposit, and using geological, geophysical, hydrogeological data and materials of uranium occurrences and anomalies obtained by previous researchers the environmental relation between the distribution of paleo-channels-alluvial proluvial fans and the dispersion-concentration of uranium are synthesized and analysed. As a result, 19 uranium metallogenic prospective areas are delineated, and the direction for further uranium prospecting is proposed
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Landslide hazard assessment of the Black sea coastline (Caucasus, Russia) via drones
Kazeev, Andrey; Postoev, German; Fedotova, Ksenia
2017-04-01
Landslide hazard assessment of slopes of Sochi was performed along the railway between the cities Tuapse and Adler (total length 103 km). The railway passes through the territory with active development of hazardous geological processes such as landslides, rock falls and debris-flows. By the beginning of 2016, 36 landslide sites were discovered along the railway (total length 34 km), 48 rock-fall sites (length 31 km), and 5 debris-flow sites (length 0.14 km). In recent years the intensification of deformations was observed. For instance, during previous 10 years (1996¬¬-2005) 28 sudden deformations occurred due to slope processes, which caused interruptions in traffic. And in the present decade (2006-2015), 72 deformations were recorded. High landslide activity and economic loss determined the necessity of complex investigations of engineering geological conditions of landslides development and causes of its intensification. The protection strategy development was needed to minimize negative consequences. Thus, the investigations of landslide situation along the railway "Tuapse - Adler" included the categorization of landslide sites by level of hazard, with risk assessment based on numerical criteria. Preliminary evaluation of landslide hazard for the railway was conducted via the analysis of archived engineering-geological documents. 13 of 36 landslide sites (total length 13 km) were selected, reflecting the variety and peculiarities of landslide displacements on slopes (both active and inactive sites). Visual field observations of landslide slopes using drone "DJI Phantom 4" were completed during the second stage of this investigation. High-resolution photographs of landslide cirques, cracks, scarp walls, vegetation features were obtained via drone, which would have been impossible to obtain from the ground in conditions of dense subtropical vegetation cover. Possible approaches to the landslide activity and hazard assessment were evaluated: slope stability
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Multidisciplinary study on anthropogenic landslides in Nepal
Puglia, Christopher; Derron, Marc-Henri; Nicolet, Pierrick; Sudmeier-Rieux, Karen; Jaboyedoff, Michel; Devkota, Sanjay
2013-04-01
Nepal is a country in which shallow landslide is a frequent phenomenon. Monsoon is the main triggering factor but anthropogenic influence is often significant too. Indeed, many infrastructures, such as roads or water pipes, are not built in a rigorous way because of a lack of funds and knowledge. In the present study we examine the technical, social and economic issues of landslide management for two sites in Nepal. The first site is located in Sanusiruwari VDC (Sindhupalchock district, central Nepal) and the second one in Namadi VDC (Ramecchap district, central Nepal). Both sites are affected by landslides induced by the construction of hydropower plants. These landslides may threaten the viability of the hydropower plants. At both sites the problems are quite similar, but the first site project is a private one and the second one is a public one implemented by the United Nations Development Programme (UNDP). For both sites, bioengineering methods using Vetiver (Vetyveria zizanioides) plantations is the main stabilization measure. To follow the progression of both landslides, fieldwork observations were conducted before and after the 2012 rainy season, including photogrammetric and distancemeter acquisitions. Main issues were discussed with communities and stakeholders of the hydropower projects through interviews and participatory risk mapping. Main issues include: lack of communication between the project managers and communities leading to conflict and the lack of maintenance of the bio-engineering sites, leading to less effective Vetiver growth and slope stabilization. Comparing the landslide management (technical, social and economic) of the two projects allows to point out some specific issues within an integrated risk perspective.
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Mapping Landslides Susceptibility in a Traditional Northern Nigerian City
Oluwafemi, Olawale A.; Yakubu, Tahir A.; Muhammad, Mahmud U.; Shitta, Nyofo; Akinwumiju, Akinola S.
2018-05-01
As a result of dearth of relevant information about Landslides Susceptibility in Nigeria, the monitoring and assessment appears intractable. Hence, the study developed a Remote Sensing approach to mapping landslides susceptibility, landuse and landcover analysis in Jos South LGA, Plateau State, Nigeria. Field Observation, SPOT 5 2009 and 2012, ASTER DEM 2009, Geological Map 2006, Topographical Map 1966 were used to map Landslide Susceptibility and Landuse /Lancover Analysis in the study area. Geospatial Analytical Operations employed using ArcGIS 10.3 and Erdas Imagine 2014 include Spatial Modeling, Vectorization, Pre-lineament Extraction, Image Processing among others. Result showed that 72.38 % of the study area is underlain by granitic rocks. The landuse/cover types delineated for the study area include floodplain (29.27 %), farmland (23.96 %), sparsely vegetated land (15.43 %), built up area (13.65 %), vegetated outcrop (8.48 %), light vegetation (5.37 %), thick vegetation (2.39 %), water body (0.58 %), plantation (0.50 %) and mining pond (0.37 %). Landslide Susceptibility Analysis also revealed that 87 % of the study area is relatively at low to very low risk of landslide event. While only 13 % of the study area is at high to very high risk of landslide event. The study revealed that the susceptibility of landslide event is very low in the study area. However, possible landslide event in the hot spots could be pronounced and could destabilize the natural and man-made environmental systems of the study area.
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LANDSLIDE SUSCEPTIBILITY ASSESSMENT THROUGH FUZZY LOGIC INFERENCE SYSTEM (FLIS
Directory of Open Access Journals (Sweden)
T. Bibi
2016-09-01
Full Text Available Landslide is among one of the most important natural hazards that lead to modification of the environment. It is a regular feature of a rapidly growing district Mansehra, Pakistan. This caused extensive loss of life and property in the district located at the foothills of Himalaya. Keeping in view the situation it is concluded that besides structural approaches the non-structural approaches such as hazard and risk assessment maps are effective tools to reduce the intensity of damage. A landslide susceptibility map is base for engineering geologists and geomorphologists. However, it is not easy to produce a reliable susceptibility map due to complex nature of landslides. Since 1980s, several mathematical models have been developed to map landslide susceptibility and hazard. Among various models this paper is discussing the effectiveness of fuzzy logic approach for landslide susceptibility mapping in District Mansehra, Pakistan. The factor maps were modified as landslide susceptibility and fuzzy membership functions were assessed for each class. Likelihood ratios are obtained for each class of contributing factors by considering the expert opinion. The fuzzy operators are applied to generate landslide susceptibility maps. According to this map, 17% of the study area is classified as high susceptibility, 32% as moderate susceptibility, 51% as low susceptibility and areas. From the results it is found that the fuzzy model can integrate effectively with various spatial data for landslide hazard mapping, suggestions in this study are hope to be helpful to improve the applications including interpretation, and integration phases in order to obtain an accurate decision supporting layer.
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The impact of landslides on urban areas and infrastructure in Italy
Trigila, Alessandro; Spizzichino, Daniele; Iadanza, Carla
2010-05-01
Landslide risk in Italy is particularly high since in addition to the geological, geomorphological, seismic and structural settings which render it susceptible to frequent and widespread landslide phenomena, the Italian territory is also densely populated and highly urbanized. In terms of landslide hazard, 485,004 landslides occurred between A.D. 1116 and 2006 within Italy, with a landslide area of 20,721 km2 equal to 6.9% of the national territory. 5,708 municipal districts are affected by landslides (70.5% of the total), of which 2,940 with extremely high levels of criticality due to landslides affecting urban centres. This data emerges from the IFFI Project (Italian Landslide Inventory) which, set up by ISPRA - Institute for Environmental Protection and Research/Geological Survey of Italy and the Regions and self-governing Provinces, identifies landslide phenomena across Italy in accordance with standardized methods of data collection, recording and mapping. With regard to exposure and vulnerability, urban areas in Italy account for 17,929 km2, equal to 5.9% of the national territory. In the past 50 years, urban areas in Italy underwent a dramatic increase, whose surface has more than doubled. Often building areas did not benefit from any form of proper land use planning and management or detailed landslide hazard assessment. Moreover unauthorized building has reached levels as high as 60% in regions of Southern Italy. This study assesses the incidence of landslide phenomena and their impacts within urban areas of Italian provincial capitals in terms of number of landslides, surface area and type of movement. The people exposed to landslide risk at national level and critical points along highways, railways and road network has been also estimated. Landslides have been classified in two main categories: rapid and slow movements. The rapid phenomena are strictly correlated to the people safety, while the slow ones concern mainly losses and usability of buildings
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McFall, B. C.; Mohammed, F.; Fritz, H. M.
2012-04-01
Tsunamis generated by landslides and volcanic island collapses account for some of the most catastrophic events. Major tsunamis caused by landslides or volcanic island collapse were recorded at Krakatoa in 1883, Grand Banks, Newfoundland in 1929, Lituya Bay, Alaska in 1958, Papua New Guinea in 1998, and Java in 2006. Source and runup scenarios based on real world events are physically modeled in the three dimensional NEES tsunami wave basin (TWB) at Oregon State University (OSU). A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The LTG consists of a sliding box filled with up to 1,350 kg of naturally rounded river gravel which is accelerated by means of four pneumatic pistons down the 2H: 1V slope, launching the granular landslide towards the water at velocities of up to 5 m/s. Topographical and bathymetric features can greatly affect wave characteristics and runup heights. Landslide tsunamis are studied in different topographic and bathymetric configurations: far field propagation and runup, a narrow fjord and curved headland configurations, and a conical island setting representing landslides off an island or a volcanic flank collapse. Water surface elevations were measured using an array of resistance wave gauges. The granulate landslide width, thickness and front velocity were measured using above and underwater cameras. Landslide 3-dimensional surface reconstruction and surface velocity properties were measured using a stereo particle image velocimetry (PIV) setup. The speckled pattern on the surface of the granular landslide allows for cross-correlation based PIV analysis. Wave runup was measured with resistance wave gauges along the slope and verified with video image processing. The measured landslide and tsunami data serve to validate and advance 3-dimensional numerical landslide tsunami and prediction models.
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A spatial database for landslides in northern Bavaria: A methodological approach
Jäger, Daniel; Kreuzer, Thomas; Wilde, Martina; Bemm, Stefan; Terhorst, Birgit
2018-04-01
Landslide databases provide essential information for hazard modeling, damages on buildings and infrastructure, mitigation, and research needs. This study presents the development of a landslide database system named WISL (Würzburg Information System on Landslides), currently storing detailed landslide data for northern Bavaria, Germany, in order to enable scientific queries as well as comparisons with other regional landslide inventories. WISL is based on free open source software solutions (PostgreSQL, PostGIS) assuring good correspondence of the various softwares and to enable further extensions with specific adaptions of self-developed software. Apart from that, WISL was designed to be particularly compatible for easy communication with other databases. As a central pre-requisite for standardized, homogeneous data acquisition in the field, a customized data sheet for landslide description was compiled. This sheet also serves as an input mask for all data registration procedures in WISL. A variety of "in-database" solutions for landslide analysis provides the necessary scalability for the database, enabling operations at the local server. In its current state, WISL already enables extensive analysis and queries. This paper presents an example analysis of landslides in Oxfordian Limestones in the northeastern Franconian Alb, northern Bavaria. The results reveal widely differing landslides in terms of geometry and size. Further queries related to landslide activity classifies the majority of the landslides as currently inactive, however, they clearly possess a certain potential for remobilization. Along with some active mass movements, a significant percentage of landslides potentially endangers residential areas or infrastructure. The main aspect of future enhancements of the WISL database is related to data extensions in order to increase research possibilities, as well as to transfer the system to other regions and countries.
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The effect of terrain factors on landslide features along forest road ...
African Journals Online (AJOL)
Results indicate that the landslide area at a distance of 80 to 100 m from road edge was significantly more than that of other distances. The landslide dimensions increased with increasing slope angle. The mean of landslide area and mean of landslide volume on the Northwest aspect was significantly more than that on ...
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Rainfall-triggered landslides, anthropogenic hazards, and mitigation strategies
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M. C. Larsen
2008-01-01
Full Text Available Rainfall-triggered landslides are part of a natural process of hillslope erosion that can result in catastrophic loss of life and extensive property damage in mountainous, densely populated areas. As global population expansion on or near steep hillslopes continues, the human and economic costs associated with landslides will increase. Landslide hazard mitigation strategies generally involve hazard assessment mapping, warning systems, control structures, and regional landslide planning and policy development. To be sustainable, hazard mitigation requires that management of natural resources is closely connected to local economic and social interests. A successful strategy is dependent on a combination of multi-disciplinary scientific and engineering approaches, and the political will to take action at the local community to national scale.
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Landslide risk reduction strategies: an inventory for the Global South
Maes, Jan; Kervyn, Matthieu; Vranken, Liesbet; Dewitte, Olivier; Vanmaercke, Matthias; Mertens, Kewan; Jacobs, Liesbet; Poesen, Jean
2015-04-01
Landslides constitute a serious problem globally. Moreover, landslide impact remains underestimated especially in the Global South. It is precisely there where the largest impact is experienced. An overview of measures taken to reduce risk of landslides in the Global South is however still lacking. Because in many countries of the Global South disaster risk reduction (DRR) is at an emerging stage, it is crucial to monitor the ongoing efforts (e.g. discussions on the Post-2015 Framework for DRR). The first objective of this study is to make an inventory of techniques and strategies that are applied to reduce risk from landslides in tropical countries. The second objective is to investigate what are the main bottlenecks for implementation of DRR strategies. In order to achieve these objectives, a review of both scientific and grey literature was conducted, supplemented with expert knowledge. The compilation of recommended and implemented DRR measures from landslide-prone tropical countries is based on an adapted classification proposed by the SafeLand project. According to Vaciago (2013), landslide risk can be reduced by either reducing the hazard, the vulnerability, the number or value of elements at risk or by sharing the residual risk. In addition, these measures can be combined with education and/or awareness raising and are influenced by governance structures and cultural beliefs. Global landslide datasets have been used to identify landslide-prone countries, augmented with region-specific datasets. Countries located in the tropics were selected in order to include landslide-prone countries with a different Human Development Index (HDI) but with a similar climate. Preliminary results support the statement made by Anderson (2013) that although the importance of shifting from post-disaster emergency actions to pre-disaster mitigation is acknowledged, in practice this paradigm shift seems rather limited. It is expected that this is especially the case in countries
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Terrinha, Pedro; Duarte, Henrique; Noiva, João; Ribeiro, Carlos; Brito, Pedro; Baptista, Maria Ana; Miranda, Miguel; Omira, Rachid; Magalhães, Vitor; Roque, Cristina
2015-04-01
The seismic stratigraphy of the Tagus estuary ebb-tidal delta of Lisbon (Portugal) is investigated with the purpose of searching for evidences of possible sedimentary or erosive features associated with landslides or mass wasting deposits (MTD) events. A special attention was given to events that could have been triggered by large earthquakes that are known to have struck the West of Portugal and Spain in historical and pre-historical times. These earthquakes destroyed Lisbon at least twice in the last 500 years, being the 1755 Lisbon earthquake of estimated magnitude >8.5. To investigate these geological features the seismic reflection dataset used in this work consists of Chirp (Lisboa98 dataset), Sparker single channel (PACEMAKER 2011 dataset) and multichannel seismic (MCS) data (TAGUSDELTA 2013 dataset). Cross-lines of MCS data were acquired crossing the core sampling sites done in previous works. Calibration of the seismic lines width the core data led to infer that the Tagus ebb delta started its formation around 17ky BP and it consists of two main stratigraphic units, the younger of which initiated its formation at approximately 13ky BP. The lower deltaic unit contains several MTDs and/or landslides that could not be mapped with the present dataset. In the upper unit we report the existence of a landslide with 10km of length, 4.5km of width and 20m of maximum thickness that accounted for the collapse of half of the Tagus river delta front. The internal structure of the landslide varies laterally. The main different aspects are, as follows, i) the landslide can be dismembered along slope due to stretching parallel associated to differential movement along slope, ii) it can show internal discontinuities that represent mechanical detachments that separate imbricate wedges and iii) distal deposited bodies completely detached from the main landslide body. The age of the landslide is discussed; an estimated age of >8ky BP is proposed by stratigraphic correlation
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Dominguez-M, L.; Castañeda, A.; Ramirez, A.; González, A. E.
2013-05-01
One of the most catastrophic events, with economical losses and deaths, in Mexico and Latin America, is the landslide event. The Juan de Grijalva landslide, which blocked one of the largest rivers in the Chiapas state of Mexico, on November 4, 2007, is considered one of the greatest that have occurred in the world in the last 100 years (Dominguez, 2008) and it could be the one with the largest economic impact in the history of Mexico. This landslide occurred four days after a period of very heavy rains that caused, in the peak of the emergency, flooding in almost 62% of the area of the state of Tabasco (CENAPRED, 2009) and is also one of the most serious disasters that were faced by the Mexican government in the past 10 years. The Juan de Grijalva landslide mobilized the entire government apparatus and required an investment of just over 0.1 billions of US Dollars (CENAPRED, 2009) for the rehabilitation of the river runway and additional works in order to prevent further damages if another landslide occurs in the vicinity. A similar case of interest for Mexican researchers and specialists in earth sciences is the big landslide occurred in the communities of Santa Cruz Mitlatongo, municipality of Magdalena Jaltepec, and Santiago Mitlatongo, municipality of Nochixtlan, both in the state of Oaxaca (Dominguez, 2011). This landslide has dimensions of just over 2,500 m long and 900 m wide, and it remains active from September 2011. Since then, the landslide has moved just over 230 m in length and has destroyed about 850 houses. Given the geological and geotechnical characteristics of these landslides and the economic and social impact caused, the National Center for Disaster Prevention (CENAPRED) has initiated a research project in order to learn the main factors (constraints and triggers) that influenced both landslides. In relation with the National Hazard Landslide Map, developed by CENAPRED, these events are an important task of the National Inventory of Landslides
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Influence of landslides on biophysical diversity — A perspective from British Columbia
Geertsema, Marten; Pojar, James J.
2007-09-01
Landslides have long been overlooked or underestimated as important natural disturbance agents. In particular the ecological role of landslides in maintaining biological diversity has been largely ignored. Here we provide a western Canadian ( British Columbian) perspective on the influences of landslides on biophysical diversity, which is related in several ways to biological diversity. We recognize several types of biophysical/ecological diversity: site diversity, soil diversity, and the derivative habitat or ecosystem (including aquatic ecosystems) diversity. There are also a variety of landslide types, depending on materials and on the rate and style of movement. We discuss the roles of different landslide types on various aspects of terrestrial diversity. Landslides are simultaneously depositional and erosional processes that influence sites by redistributing materials and changing surface expression — usually creating a complex microtopography that can include very dry ridges and hummocks, and sometimes depressions with standing water. Landslide impacts to site also influence soil and soil development. Portions of landslides with exposed parent material are set back to the initial stages of soil development and ecological succession. Landslides can also change soil density, structure, porosity, surface texture, chemistry and microclimate. By changing site and soil, landslides also influence habitat. Landslides influence habitat diversity by engendering a mosaic of seral stages (often both primary and secondary), and in overwhelmingly forested landscapes often create nodes or hotspots of non-forested habitat and biota. In some areas, like the boreal forest, there is an important interplay between landslides and fire, while on the coast of British Columbia debris and snow avalanches can be the dominant disturbance agent. Low-gradient and deep-seated landslides are often opportunistically colonized by beaver and other water and shrub-loving fauna. Sag ponds and
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A tectonic reconstruction of accreted terranes along the paleo-Pacific margin of Gondwana
Bammel, Brandon
The southern oceanic margin of Gondwana was nearly 40,000 km long or 24,854.8 miles. The southern margin was the result of the Terra Australis orogen. Spanning 18,000 km or 11,184.7 miles and is proposed as one of the largest and longest lived orogens in Earth history. The paleo-Pacific margin of Gondwana consisted of segments of the Australian-Antarctic craton, southern South America (modern Argentina and Chile), southern South Africa, Marie Byrdland, New Zealand and its adjacent continental shelf, the Ellsworth Mountains, and the Transantarctic Mountains. The process of terrane accretion has played a substantial part in the assembly of the continents as they look today. The paleo-Pacific margin of Gondwana was an active region of terrane accretion from the Neoproterozoic to the Late Mesozoic. This research study examines the accretion of terranes across the paleo-Pacific Gondwana margin to provide a comprehensive reconstruction. A paleogeographic basemap was created using PALEOMAP Project maps and the geology data was provided by the School of Geoscience from the University of Witwatersrand of South Africa. Location and data analyzed for terranes were collected building a PDF library of journal articles across numerous geological publications.
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Toward a comprehensive areal model of earthquake-induced landslides
Miles, S.B.; Keefer, D.K.
2009-01-01
This paper provides a review of regional-scale modeling of earthquake-induced landslide hazard with respect to the needs for disaster risk reduction and sustainable development. Based on this review, it sets out important research themes and suggests computing with words (CW), a methodology that includes fuzzy logic systems, as a fruitful modeling methodology for addressing many of these research themes. A range of research, reviewed here, has been conducted applying CW to various aspects of earthquake-induced landslide hazard zonation, but none facilitate comprehensive modeling of all types of earthquake-induced landslides. A new comprehensive areal model of earthquake-induced landslides (CAMEL) is introduced here that was developed using fuzzy logic systems. CAMEL provides an integrated framework for modeling all types of earthquake-induced landslides using geographic information systems. CAMEL is designed to facilitate quantitative and qualitative representation of terrain conditions and knowledge about these conditions on the likely areal concentration of each landslide type. CAMEL is highly modifiable and adaptable; new knowledge can be easily added, while existing knowledge can be changed to better match local knowledge and conditions. As such, CAMEL should not be viewed as a complete alternative to other earthquake-induced landslide models. CAMEL provides an open framework for incorporating other models, such as Newmark's displacement method, together with previously incompatible empirical and local knowledge. ?? 2009 ASCE.
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Mitigation of landslide area around railway tunnel, South Sumatra Province, Indonesia
Toha, M. Taufik; Setiabudidaya, Dedi; Komar, Syamsul; Bochori, Ghadafi, Moamar A.; Adiwarman, Mirza; Rahim, S. E.
2017-09-01
Adequate and safe railway line infrastructures as well as facilities are required to support the rail transport system in South Sumatra. The slope stability along railway line of Lahat-Lubuk Linggau South Sumatra were studied during landslide that occured on January 23th, 2016. The landslide occurred on the mouth of railway tunnel in Gunung Gajah Village, Lahat District that causing the railway transportation system had to be stopped for a few days. A comprehensive research was conducted to analyze the causes of the landslide and to identify other landslide risky areas along the railway line Lahat-Lubuk Linggau. The research activities included surveying, sampling, laboratory testing, investigating condition of geology, geotechnics, hydrogeology/hydrology, morphology and land use. The factors that cause landslide in the past studies were found to be morphology, structural geology, physical and mechanical characteristics, hydrogeology, hydrology, external forces (train vibration, earthquake). Results back analysis of slope stability when the landslide occurred showed that the value Safety Factor (SF) = 1, angle of friction = 0°, and cohesion = 0.49 kg/cm2 (49 kPa). Based on the observation and analysis of the condition of the morphology and orientation of the structure of the rock layers, there was a location prone to landslide (labile) in the surrounding area of the landslide. Mitigations to potential landslide in adjacent area were building a retaining wall, draining channels, and shortcrete at the rock wall after landslides and maintaining the land use around the slopes.
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Susceptibility analysis of landslide in Chittagong City Corporation Area, Bangladesh
Directory of Open Access Journals (Sweden)
Sourav Das
2015-06-01
Full Text Available In Chittagong city, landslide phenomena is the most burning issue which causes great problems to the life and properties and it is increasing day by day and becoming one of the main problems of city life. On 11 June 2007, a massive landslide happened in Chittagong City Corporation (CCC area, a large number of foothill settlements and slums were demolished; more than 90 people died and huge resource destruction took place. It is therefore essential to analyze the landslide susceptibility for CCC area to prepare mitigation strategies as well as assessing the impacts of climate change. To assess community susceptibility of landslide hazard, a landslide susceptibility index map has been prepared using analytical hierarchy process (AHP model based on geographic information system (GIS and remote sensing (RS and its susceptibility is analyzed through community vulnerability assessment tool (CVAT. The major findings of the research are 27% of total CCC area which is susceptible to landslide hazard and whereas 6.5 sq.km areas are found very highly susceptible. The landslide susceptible areas of CCC have also been analyzed in respect of physical, social, economic, environmental and critical facilities and it is found that the overall CCC area is highly susceptible to landslide hazard. So the findings of the research can be utilized to prioritize risk mitigation investments, measures to strengthen the emergency preparedness and response mechanisms for reducing the losses and damages due to future landslide events. DOI: http://dx.doi.org/10.3126/ije.v4i2.12635 International Journal of Environment Vol.4(2 2015: 157-181
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Regional Landslide Hazard Assessment Considering Potential Climate Change
Almeida, S.; Holcombe, E.; Pianosi, F.; Wagener, T.
2016-12-01
Landslides have many negative economic and societal impacts, including the potential for significant loss of life and damage to infrastructure. These risks are likely to be exacerbated in the future by a combination of climatic and socio-economic factors. Climate change, for example, is expected to increase the occurrence of rainfall-triggered landslides, because a warmer atmosphere tends to produce more high intensity rainfall events. Prediction of future changes in rainfall, however, is subject to high levels of uncertainty, making it challenging for decision-makers to identify the areas and populations that are most vulnerable to landslide hazards. In this study, we demonstrate how a physically-based model - the Combined Hydrology and Stability Model (CHASM) - can be used together with Global Sensitivity Analysis (GSA) to explore the underlying factors controlling the spatial distribution of landslide risks across a regional landscape, while also accounting for deep uncertainty around potential future rainfall triggers. We demonstrate how GSA can be used to analyse CHASM which in turn represents the spatial variability of hillslope characteristics in the study region, while accounting for other uncertainties. Results are presented in the form of landslide hazard maps, utilising high-resolution digital elevation datasets for a case study in St Lucia in the Caribbean. Our findings about spatial landslide hazard drivers have important implications for data collection approaches and for long-term decision-making about land management practices.
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Guidance Index for Shallow Landslide Hazard Analysis
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Cheila Avalon Cullen
2016-10-01
Full Text Available Rainfall-induced shallow landslides are one of the most frequent hazards on slanted terrains. Intense storms with high-intensity and long-duration rainfall have high potential to trigger rapidly moving soil masses due to changes in pore water pressure and seepage forces. Nevertheless, regardless of the intensity and/or duration of the rainfall, shallow landslides are influenced by antecedent soil moisture conditions. As of this day, no system exists that dynamically interrelates these two factors on large scales. This work introduces a Shallow Landslide Index (SLI as the first implementation of antecedent soil moisture conditions for the hazard analysis of shallow rainfall-induced landslides. The proposed mathematical algorithm is built using a logistic regression method that systematically learns from a comprehensive landslide inventory. Initially, root-soil moisture and rainfall measurements modeled from AMSR-E and TRMM respectively, are used as proxies to develop the index. The input dataset is randomly divided into training and verification sets using the Hold-Out method. Validation results indicate that the best-fit model predicts the highest number of cases correctly at 93.2% accuracy. Consecutively, as AMSR-E and TRMM stopped working in October 2011 and April 2015 respectively, root-soil moisture and rainfall measurements modeled by SMAP and GPM are used to develop models that calculate the SLI for 10, 7, and 3 days. The resulting models indicate a strong relationship (78.7%, 79.6%, and 76.8% respectively between the predictors and the predicted value. The results also highlight important remaining challenges such as adequate information for algorithm functionality and satellite based data reliability. Nevertheless, the experimental system can potentially be used as a dynamic indicator of the total amount of antecedent moisture and rainfall (for a given duration of time needed to trigger a shallow landslide in a susceptible area. It is
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Lacroix, Pascal; Perfettini, Hugo; Berthier, Etienne; Taipe, Edu; Guillier, Bertrand
2015-04-01
Major earthquakes in mountainous areas often trigger landslides. The impact of earthquakes on slow-moving landslides is however not well constrained due to few co-seismic measurements of landslide motion. We document the first time-series of a landslide reactivation by an earthquake (Mw6.0, distance 20 km), using continuous GPS measurements over the Maca landslide (Peru). Our survey shows a coseismic response of the landslide of about 2 cm, followed by a relaxation period of 5 weeks during which postseismic slip is three times greater than the coseismic displacement itself. Our results confirm the coseismic activation of landslides and provide the first observation of a post seismic displacement. Finally, a multi-temporal survey using images from the very high resolution Pléiades optical satellite, allowed us to detect 9 active slow-moving landslides over the whole valley. Their pattern of motion show they have been reactivated by the same earthquake. We analyze this small but comprehensive database of landslides reactivated by the earthquake. We find that the landslide motion due to the earthquake is function of the shaking intensity, suggesting a friction at the basal interface dependent on the earthquake solicitation. These various observations are consistent with a mechanical model where slip on the landslide basal interface is governed by rate and state friction, analogous to the mechanics of creeping tectonic faults.
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West, A. Joshua; Hetzel, Ralf; Li, Gen; Jin, Zhangdong; Zhang, Fei; Hilton, Robert G.; Densmore, Alexander L.
2014-06-01
The concentration of 10Be in detrital quartz (10Beqtz) from river sediments is now widely used to quantify catchment-wide denudation rates but may also be sensitive to inputs from bedrock landslides that deliver sediment with low 10Beqtz. Major landslide-triggering events can provide large amounts of low-concentration material to rivers in mountain catchments, but changes in river sediment 10Beqtz due to such events have not yet been measured directly. Here we examine the impact of widespread landslides triggered by the 2008 Wenchuan earthquake on 10Beqtz in sediment samples from the Min Jiang river basin, in Sichuan, China. Landslide deposit material associated with the Wenchuan earthquake has consistently lower 10Beqtz than in river sediment prior to the earthquake. River sediment 10Beqtz decreased significantly following the earthquake downstream of areas of high coseismic landslide occurrence (i.e., with greater than ∼0.3% of the upstream catchment area affected by landslides), because of input of the 10Be-depleted landslide material, but showed no systematic changes where landslide occurrence was low. Changes in river sediment 10Beqtz concentration were largest in small first-order catchments but were still significant in large river basins with areas of 104-105 km. Spatial and temporal variability in river sediment 10Beqtz has important implications for inferring representative denudation rates in tectonically active, landslide-dominated environments, even in large basins. Although the dilution of 10Beqtz in river sediment by landslide inputs may complicate interpretation of denudation rates, it also may provide a possible opportunity to track the transport of landslide sediment. The associated uncertainties are large, but in the Wenchuan case, calculations based on 10Be mixing proportions suggest that river sediment fluxes in the 2-3 years following the earthquake increased by a similar order of magnitude in the 0.25-1 mm and the mixing calculations and
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Shao, Wei; Bogaard, Thom; Bakker, Mark; Berti, Matteo
2016-12-01
The fast pore water pressure response to rain events is an important triggering factor for slope instability. The fast pressure response may be caused by preferential flow that bypasses the soil matrix. Currently, most of the hydro-mechanical models simulate pore water pressure using a single-permeability model, which cannot quantify the effects of preferential flow on pressure propagation and landslide triggering. Previous studies showed that a model based on the linear-diffusion equation can simulate the fast pressure propagation in near-saturated landslides such as the Rocca Pitigliana landslide. In such a model, the diffusion coefficient depends on the degree of saturation, which makes it difficult to use the model for predictions. In this study, the influence of preferential flow on pressure propagation and slope stability is investigated with a 1D dual-permeability model coupled with an infinite-slope stability approach. The dual-permeability model uses two modified Darcy-Richards equations to simultaneously simulate the matrix flow and preferential flow in hillslopes. The simulated pressure head is used in an infinite-slope stability analysis to identify the influence of preferential flow on the fast pressure response and landslide triggering. The dual-permeability model simulates the height and arrival of the pressure peak reasonably well. Performance of the dual-permeability model is as good as or better than the linear-diffusion model even though the dual-permeability model is calibrated for two single pulse rain events only, while the linear-diffusion model is calibrated for each rain event separately. In conclusion, the 1D dual-permeability model is a promising tool for landslides under similar conditions.
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Challenges for operational forecasting and early warning of rainfall induced landslides
Guzzetti, Fausto
2017-04-01
In many areas of the world, landslides occur every year, claiming lives and producing severe economic and environmental damage. Many of the landslides with human or economic consequences are the result of intense or prolonged rainfall. For this reason, in many areas the timely forecast of rainfall-induced landslides is of both scientific interest and social relevance. In the recent years, there has been a mounting interest and an increasing demand for operational landslide forecasting, and for associated landslide early warning systems. Despite the relevance of the problem, and the increasing interest and demand, only a few systems have been designed, and are currently operated. Inspection of the - limited - literature on operational landslide forecasting, and on the associated early warning systems, reveals that common criteria and standards for the design, the implementation, the operation, and the evaluation of the performances of the systems, are lacking. This limits the possibility to compare and to evaluate the systems critically, to identify their inherent strengths and weaknesses, and to improve the performance of the systems. Lack of common criteria and of established standards can also limit the credibility of the systems, and consequently their usefulness and potential practical impact. Landslides are very diversified phenomena, and the information and the modelling tools used to attempt landslide forecasting vary largely, depending on the type and size of the landslides, the extent of the geographical area considered, the timeframe of the forecasts, and the scope of the predictions. Consequently, systems for landslide forecasting and early warning can be designed and implemented at several different geographical scales, from the local (site or slope specific) to the regional, or even national scale. The talk focuses on regional to national scale landslide forecasting systems, and specifically on operational systems based on empirical rainfall threshold
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A new methodology for modeling of direct landslide costs for transportation infrastructures
Klose, Martin; Terhorst, Birgit
2014-05-01
The world's transportation infrastructure is at risk of landslides in many areas across the globe. A safe and affordable operation of traffic routes are the two main criteria for transportation planning in landslide-prone areas. The right balancing of these often conflicting priorities requires, amongst others, profound knowledge of the direct costs of landslide damage. These costs include capital investments for landslide repair and mitigation as well as operational expenditures for first response and maintenance works. This contribution presents a new methodology for ex post assessment of direct landslide costs for transportation infrastructures. The methodology includes tools to compile, model, and extrapolate landslide losses on different spatial scales over time. A landslide susceptibility model enables regional cost extrapolation by means of a cost figure obtained from local cost compilation for representative case study areas. On local level, cost survey is closely linked with cost modeling, a toolset for cost estimation based on landslide databases. Cost modeling uses Landslide Disaster Management Process Models (LDMMs) and cost modules to simulate and monetize cost factors for certain types of landslide damage. The landslide susceptibility model provides a regional exposure index and updates the cost figure to a cost index which describes the costs per km of traffic route at risk of landslides. Both indexes enable the regionalization of local landslide losses. The methodology is applied and tested in a cost assessment for highways in the Lower Saxon Uplands, NW Germany, in the period 1980 to 2010. The basis of this research is a regional subset of a landslide database for the Federal Republic of Germany. In the 7,000 km² large Lower Saxon Uplands, 77 km of highway are located in potential landslide hazard area. Annual average costs of 52k per km of highway at risk of landslides are identified as cost index for a local case study area in this region. The
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Weights of Evidence Method for Landslide Susceptibility Mapping in Takengon, Central Aceh, Indonesia
Pamela; Sadisun, Imam A.; Arifianti, Yukni
2018-02-01
Takengon is an area prone to earthquake disaster and landslide. On July 2, 2013, Central Aceh earthquake induced large numbers of landslides in Takengon area, which resulted in casualties of 39 people. This location was chosen to assess the landslide susceptibility of Takengon, using a statistical method, referred to as the weight of evidence (WoE). This WoE model was applied to indicate the main factors influencing the landslide susceptible area and to derive landslide susceptibility map of Takengon. The 251 landslides randomly divided into two groups of modeling/training data (70%) and validation/test data sets (30%). Twelve thematic maps of evidence are slope degree, slope aspect, lithology, land cover, elevation, rainfall, lineament, peak ground acceleration, curvature, flow direction, distance to river and roads used as landslide causative factors. According to the AUC, the significant factor controlling the landslide is the slope, the slope aspect, peak ground acceleration, elevation, lithology, flow direction, lineament, and rainfall respectively. Analytical result verified by using test data of landslide shows AUC prediction rate is 0.819 and AUC success rate with all landslide data included is 0.879. This result showed the selective factors and WoE method as good models for assessing landslide susceptibility. The landslide susceptibility map of Takengon shows the probabilities, which represent relative degrees of susceptibility for landslide proneness in Takengon area.
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Soil characteristics of landslides on Mount Elgon (Uganda): implications for estimating their age
Van Eynde, Elise; Dondeyne, Stefaan; Isabirye, Moses; Deckers, Jozef; Poesen, Jean
2017-04-01
The slopes of Mount Elgon, a complex volcano at the border between Uganda and Kenya, are frequently affected by landslides with disastrous effects on the livelihood of its population. Since local people greatly depend on the land for crop production, we examined if and how fast physico-chemical characteristics in landslide scars recover. A chronosequence of 18 landslides covering a period of 103 years was sampled in order to explore differences between topsoil within and outside landslide scars. For each landslide, two topsoil samples were taken within the landslide and two in nearby undisturbed soils to compare their physico-chemical characteristics. No differences were found for available P, Ca2+, Mg2+ content or for the fine earth texture. Recent landslides had however lower content of soil organic carbon (OC) and K+, and higher content of rock fragments and Na+ than the adjacent soils. Soil OC content increased significantly with age and reached levels of the corresponding undisturbed soils after ca. 60 years. Older landslides had even higher OC contents than soils adjacent to the landslide. Hence landslide scars act as local carbon sink. We suggest that the occurrence of rock fragments in the topsoil is a useful indicator for mapping past landslides. Moreover, the difference in soil OC content between landslide scars and adjacent soil could be used for estimating the age of landslides in data-poor regions.
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Landslides triggered by the 1946 Ancash earthquake, Peru
Kampherm, T. S.; Evans, S. G.; Valderrama Murillo, P.
2009-04-01
The 1946 M7.3 Ancash Earthquake triggered a large number of landslides in an epicentral area that straddled the Continental Divide of South America in the Andes of Peru. A small number of landslides were described in reconnaissance reports by E. Silgado and Arnold Heim published shortly after the earthquake, but further details of the landslides triggered by the earthquake have not been reported since. Utilising field traverses, aerial photograph interpretation and GIS, our study mapped 45 landslides inferred to have been triggered by the event. 83% were rock avalanches involving Cretaceous limestones interbedded with shales. The five largest rock/debris avalanches occurred at Rio Llama (est. vol. 37 M m3), Suytucocha (est. vol., 13.5 Mm3), Quiches (est. vol. 10.5 Mm3 ), Pelagatos (est. vol. 8 Mm3), and Shundoy (est. vol. 8 Mm3). The Suytucocha, Quiches, and Pelagatos landslides were reported by Silgado and Heim. Rock slope failure was most common on slopes with a southwest aspect, an orientation corresponding to the regional dip direction of major planar structures in the Andean foreland belt (bedding planes and thrust faults). In valleys oriented transverse to the NW-SE structural grain of the epicentral area, south-westerly dipping bedding planes combined with orthogonal joint sets to form numerous wedge failures. Many initial rock slope failures were transformed into rock/debris avalanches by the entrainment of colluvium in their path. At Acobamba, a rock avalanche that transformed into a debris avalanche (est. vol. 4.3 Mm3) overwhelmed a village resulting in the deaths of 217 people. The cumulative volume-frequency plot shows a strong power law relation below a marked rollover, similar in form to that derived for landslides triggered by the 1994 Northridge Earthquake. The total volume of the 45 landslides is approximately 93 Mm3. The data point for the Ancash Earthquake plots near the regression line calculated by Keefer (1994), and modified by Malamud et al
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Assessment of Rainfall-induced Landslide Potential and Spatial Distribution
Chen, Yie-Ruey; Tsai, Kuang-Jung; Chen, Jing-Wen; Chiang, Jie-Lun; Hsieh, Shun-Chieh; Chue, Yung-Sheng
2016-04-01
Recently, due to the global climate change, most of the time the rainfall in Taiwan is of short duration but with high intensity. Due to Taiwan's steep terrain, rainfall-induced landslides often occur and lead to human causalities and properties loss. Taiwan's government has invested huge reconstruction funds to the affected areas. However, after rehabilitation they still face the risk of secondary sediment disasters. Therefore, this study assesses rainfall-induced (secondary) landslide potential and spatial distribution in watershed of Southern Taiwan under extreme climate change. The study areas in this research are Baolai and Jianshan villages in the watershed of the Laonongxi River Basin in the Southern Taiwan. This study focused on the 3 years after Typhoon Morakot (2009 to 2011). During this period, the study area experienced six heavy rainfall events including five typhoons and one heavy rainfall. The genetic adaptive neural network, texture analysis and GIS were implemented in the analysis techniques for the interpretation of satellite images and to obtain surface information and hazard log data and to analyze land use change. A multivariate hazards evaluation method was applied to quantitatively analyze the weights of various natural environmental and slope development hazard factors. Furthermore, this study established a slope landslide potential assessment model and depicted a slope landslide potential diagram by using the GIS platform. The interaction between (secondary) landslide mechanism, scale, and location was analyzed using association analysis of landslide historical data and regional environmental characteristics. The results of image classification before and after six heavy rainfall events show that the values of coefficient of agreement are at medium-high level. By multivariate hazards evaluation method, geology and the effective accumulative rainfall (EAR) are the most important factors. Slope, distance from fault, aspect, land disturbance
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Multi-scale landslide risk assessment in Cuba
Castellanos Abella, E.A.
2008-01-01
Landslides cause a considerable amount of damage in the mountainous regions of Cuba, which cover about 25% of the territory. Until now, only a limited amount of research has been carried out in the field of landslide risk assessment in the country. This research presents a methodology and its
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Vulnerability assessment for reinforced concrete buildings exposed to landslides
International Nuclear Information System (INIS)
Mavrouli, O.; Corominas, J.; Fotopoulou, S.; Pitilakis, K.; Zuccaro, G.; Cacace, F.; De Gregorio, D.; Santo, A.; Di Crescenzo, G.; Foerster, E.; Ulrich, T.
2014-01-01
The methodologies available for the analytical quantification of the vulnerability of buildings which are subject to actions resulting from slope instabilities and landslides are relatively limited in comparison with other components of quantitative landslide risk assessment. This paper provides a general methodology for calculating the vulnerabilities of reinforced concrete frame structures that are subject to three types of slope instability: slow-moving landslides, rapid flow-type slides and rock falls. The vulnerability is expressed using sets of fragility curves. A description of the general framework and of the specialised procedures employed is presented here, separately for each landslide mechanism, through the example of a single-bay one-storey reinforced concrete frame. The properties of the frame are taken into account as variables with associated uncertainties. The derived vulnerability curves presented here can be used directly by risk assessment practitioners without having to repeat the procedure, given the expected range of landslide intensities and for similar building typologies and ranges of structural characteristics. This permits the applicability of the calculated vulnerability to a wide variety of similar frames for a range of landslide intensity parameters. (authors)
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Climate-Induced Landsliding within the Larch Dominant Permafrost Zone of Central Siberia
Kharuk, Viacheslav I.; Shushpanov, Alexandr S.; Im, Sergei T.; Ranson, Kenneth J.
2016-01-01
Climate impact on landslide occurrence and spatial patterns were analyzed within the larch-dominant communities associated with continuous permafrost areas of central Siberia. We used high resolution satellite imagery (i.e. QuickBird, WorldView) to identify landslide scars over an area of 62 000 km2. Landslide occurrence was analyzed with respect to climate variables (air temperature, precipitation, drought index SPEI), and Gravity Recovery and Climate Experiment satellite derived equivalent of water thickness anomalies (EWTA). Landslides were found only on southward facing slopes, and the occurrence of landslides increased exponentially with increasing slope steepness. Lengths of landslides correlated positively with slope steepness. The observed upper elevation limit of landslides tended to coincide with the tree line. Observations revealed landslides occurrence was also found to be strongly correlated with August precipitation (r = 0.81) and drought index (r = 0.7), with June-July-August soil water anomalies (i.e., EWTA, r = 0.68-0.7), and number of thawing days (i.e., a number of days with t (max) > 0 deg C; r = 0.67). A significant increase in the variance of soil water anomalies was observed, indicating that occurrence of landslides may increase even with a stable mean precipitation level. The key-findings of this study are (1) landslides occurrence increased within the permafrost zone of central Siberia in the beginning of the 21st century; (2) the main cause of increased landslides occurrence are extremes in precipitation and soil water anomalies; and (3) landslides occurrence are strongly dependent on relief features such as southward facing steep slopes.
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Towards an EO-based Landslide Web Mapping and Monitoring Service
Hölbling, Daniel; Weinke, Elisabeth; Albrecht, Florian; Eisank, Clemens; Vecchiotti, Filippo; Friedl, Barbara; Kociu, Arben
2017-04-01
National and regional authorities and infrastructure maintainers in mountainous regions require accurate knowledge of the location and spatial extent of landslides for hazard and risk management. Information on landslides is often collected by a combination of ground surveying and manual image interpretation following landslide triggering events. However, the high workload and limited time for data acquisition result in a trade-off between completeness, accuracy and detail. Remote sensing data offers great potential for mapping and monitoring landslides in a fast and efficient manner. While facing an increased availability of high-quality Earth Observation (EO) data and new computational methods, there is still a lack in science-policy interaction and in providing innovative tools and methods that can easily be used by stakeholders and users to support their daily work. Taking up this issue, we introduce an innovative and user-oriented EO-based web service for landslide mapping and monitoring. Three central design components of the service are presented: (1) the user requirements definition, (2) the semi-automated image analysis methods implemented in the service, and (3) the web mapping application with its responsive user interface. User requirements were gathered during semi-structured interviews with regional authorities. The potential users were asked if and how they employ remote sensing data for landslide investigation and what their expectations to a landslide web mapping service regarding reliability and usability are. The interviews revealed the capability of our service for landslide documentation and mapping as well as monitoring of selected landslide sites, for example to complete and update landslide inventory maps. In addition, the users see a considerable potential for landslide rapid mapping. The user requirements analysis served as basis for the service concept definition. Optical satellite imagery from different high resolution (HR) and very high
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Detection of rainfall-induced landslides on regional seismic networks
Manconi, Andrea; Coviello, Velio; Gariano, Stefano Luigi; Picozzi, Matteo
2017-04-01
Seismic techniques are increasingly adopted to detect signals induced by mass movements and to quantitatively evaluate geo-hydrological hazards at different spatial and temporal scales. By analyzing landslide-induced seismicity, it is possible obtaining significant information on the source of the mass wasting, as well as on its dynamics. However, currently only few studies have performed a systematic back analysis on comprehensive catalogues of events to evaluate the performance of proposed algorithms. In this work, we analyze a catalogue of 1058 landslides induced by rainfall in Italy. Among these phenomena, there are 234 rock falls, 55 debris flows, 54 mud flows, and 715 unspecified shallow landslides. This is a subset of a larger catalogue collected by the Italian research institute for geo-hydrological protection (CNR IRPI) during the period 2000-2014 (Brunetti et al., 2015). For each record, the following information are available: the type of landslide; the geographical location of the landslide (coordinates, site, municipality, province, and 3 classes of geographic accuracy); the temporal information on the landslide occurrence (day, month, year, time, date, and 3 classes of temporal accuracy); the rainfall conditions (rainfall duration and cumulated event rainfall) that have resulted in the landslide. We consider here only rainfall-induced landslides for which exact date and time were known from chronicle information. The analysis of coeval seismic data acquired by regional seismic networks show clear signals in at least 3 stations for 64 events (6% of the total dataset). Among them, 20 are associated to local earthquakes and 2 to teleseisms; 10 are anomalous signals characterized by irregular and impulsive waveforms in both time and frequency domains; 33 signals are likely associated to the landslide occurrence, as they have a cigar-shaped waveform characterized by emerging onsets, duration of several tens of seconds, and low frequencies (1-10 Hz). For
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Automatic Extraction and Size Distribution of Landslides in Kurdistan Region, NE Iraq
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Arsalan A. Othman
2013-05-01
Full Text Available This study aims to assess the localization and size distribution of landslides using automatic remote sensing techniques in (semi- arid, non-vegetated, mountainous environments. The study area is located in the Kurdistan region (NE Iraq, within the Zagros orogenic belt, which is characterized by the High Folded Zone (HFZ, the Imbricated Zone and the Zagros Suture Zone (ZSZ. The available reference inventory includes 3,190 landslides mapped from sixty QuickBird scenes using manual delineation. The landslide types involve rock falls, translational slides and slumps, which occurred in different lithological units. Two hundred and ninety of these landslides lie within the ZSZ, representing a cumulated surface of 32 km2. The HFZ implicates 2,900 landslides with an overall coverage of about 26 km2. We first analyzed cumulative landslide number-size distributions using the inventory map. We then proposed a very simple and robust algorithm for automatic landslide extraction using specific band ratios selected upon the spectral signatures of bare surfaces as well as posteriori slope and the normalized difference vegetation index (NDVI thresholds. The index is based on the contrast between landslides and their background, whereas the landslides have high reflections in the green and red bands. We applied the slope threshold map to remove low slope areas, which have high reflectance in red and green bands. The algorithm was able to detect ~96% of the recent landslides known from the reference inventory on a test site. The cumulative landslide number-size distribution of automatically extracted landslide is very similar to the one based on visual mapping. The automatic extraction is therefore adapted for the quantitative analysis of landslides and thus can contribute to the assessment of hazards in similar regions.
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The Hollin Hill Landslide Observatory - a decade of geophysical characterization and monitoring
Uhlemann, S.; Wilkinson, P. B.; Meldrum, P.; Smith, A.; Dixon, N.; Merritt, A.; Swift, R. T.; Whiteley, J.; Gunn, D.; Chambers, J. E.
2017-12-01
Landslides are major and frequent natural hazards. They shape the Earth's surface, and endanger communities and infrastructure worldwide. Within the last decade, landslides caused more than 28,000 fatalities and direct damage exceeding $1.8 billion. Climate change, causing more frequent weather extremes, is likely to increase occurrences of shallow slope failures worldwide. Thus, there is a need to improve our understanding of these shallow, rainfall-induced landslides. In this context, integrated geophysical characterization and monitoring can play a crucial role by providing volumetric data that can be linked to the hydrological and geotechnical conditions of a slope. This enables understanding of the complex hydrological processes most-often being associated with landslides. Here we present a review of a decade of characterizing and monitoring a complex, inland, clayey landslide - forming the "Hollin Hill Landslide Observatory". Within the last decade, this landslide has experienced different activity characteristics, including creep, flow, and rotational failures - thereby providing an excellent testbed for the development of geophysical and geotechnical monitoring instrumentation and methodologies. These include developments of 4D geoelectrical monitoring techniques to estimate electrode positions from the resistivity data, incorporating these into a time-lapse inversion, and imaging moisture dynamics that control the landslide behaviour. Other developments include acoustic emission monitoring, and active and passive seismic monitoring. This work is underpinned by detailed characterization of the landslide, using geomorphological and geological mapping, geotechnical investigations, and a thorough geoelectrical and seismic characterization of the landslide mass. Hence, the data gained from the Hollin Hill landslide observatory has improved our understanding of the shallow landslide dynamics in response to climate change, their mechanics and evolution. The
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Cold-water coral banks and submarine landslides: a review
de Mol, Ben; Huvenne, Veerle; Canals, Miquel
2009-06-01
This paper aims to review the relation between cold-water coral bank development and submarine landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these locations, positive and negative relationships between both features are discussed, based on available datasets. Locally submarine landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of submarine landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between submarine landslides and cold-water coral banks.
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UAV Based Agricultural Planning and Landslide Monitoring
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Servet Yaprak
2017-12-01
Full Text Available The use of Unmanned Aerial Vehicle (UAV tools has become widespread in map production, land surveying, landslide, erosion monitoring, monitoring of agricultural activities, aerial crop surveying, forest fire detection and monitoring operations. In this study, GEO 2 UAV manufactured by TEKNOMER equipped with SONY A6000 camera has been used. The flight plan have been performed with 100 m altitude, with 80% longitudinal and 60% side overlapping. Ground Control Points (GCPs have been observed with Topcon and Trimble GNSS geodetic receivers. Recorded GNSS signals have been processed with LGO V.8.4 software to get sensitive location information. 985 photos have been taken for the 344 hectares the agricultural area. 291 photos have been taken for 50 hectares the landslide area. All photos were processed by PIX4D software. For the agricultural area, 25 GCPs and for the landslide area, 8 GCPs have been included in the evaluation. 3D images were produced with pixel matching algorithms. As a result, the RMS evaluation was obtained as ±0.054 m for the agricultural area and as ±0.018 m for the landslide area. UAV images have indisputable contributions to the management of catastrophes such as landslides and earthquakes, and it is impossible to make terrestrial measurements in areas where disaster impact continues.
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Yilmaz, Işık
2009-06-01
The purpose of this study is to compare the landslide susceptibility mapping methods of frequency ratio (FR), logistic regression and artificial neural networks (ANN) applied in the Kat County (Tokat—Turkey). Digital elevation model (DEM) was first constructed using GIS software. Landslide-related factors such as geology, faults, drainage system, topographical elevation, slope angle, slope aspect, topographic wetness index (TWI) and stream power index (SPI) were used in the landslide susceptibility analyses. Landslide susceptibility maps were produced from the frequency ratio, logistic regression and neural networks models, and they were then compared by means of their validations. The higher accuracies of the susceptibility maps for all three models were obtained from the comparison of the landslide susceptibility maps with the known landslide locations. However, respective area under curve (AUC) values of 0.826, 0.842 and 0.852 for frequency ratio, logistic regression and artificial neural networks showed that the map obtained from ANN model is more accurate than the other models, accuracies of all models can be evaluated relatively similar. The results obtained in this study also showed that the frequency ratio model can be used as a simple tool in assessment of landslide susceptibility when a sufficient number of data were obtained. Input process, calculations and output process are very simple and can be readily understood in the frequency ratio model, however logistic regression and neural networks require the conversion of data to ASCII or other formats. Moreover, it is also very hard to process the large amount of data in the statistical package.
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Wohlers, Annika; Damm, Bodo
2017-04-01
Regional data of the Central German Uplands are extracted from the German landslide database in order to understand the complex interactions between landslide risks and public risk awareness considering transportation infrastructure. Most information within the database is gathered by means of archive studies from inventories of emergency agencies, state, press and web archives, company and department records as well as scientific and (geo)technical literature. The information includes land use practices, repair and mitigation measures with resultant costs of the German road network as well as railroad and waterway networks. It therefore contains valuable information of historical and current landslide impacts, elements at risk and provides an overview of spatiotemporal changes in social exposure and vulnerability to landslide hazards over the last 120 years. On a regional scale the recorded infrastructure damages, and consequential repair or mitigation measures were categorized and classified, according to relevant landslide types, processes and types of infrastructure. In a further step, the data of recent landslides are compared with historical and modern repair and mitigation measures and are correlated with socioeconomic concepts. As a result, it is possible to identify some complex interactions between landslide hazard, risk perception, and damage impact, including time lags and intensity thresholds. The data reveal distinct concepts of repairing respectively mitigating landslides on different types of transportation infrastructure, which are not exclusively linked to higher construction efforts (e.g. embankments on railroads and channels), but changing levels of economic losses and risk perception as well. In addition, a shift from low cost prevention measures such as the removal of loose rock and vegetation, rock blasting, and catch barriers towards expensive mitigation measures such as catch fences, soil anchoring and rock nailing over time can be noticed
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Citizen science, GIS, and the global hunt for landslides
Juang, C.; Stanley, T.; Kirschbaum, D.
2017-12-01
Landslides occur across the United States and around the world, causing much suffering and infrastructure damage. Many of these events have been recorded in the Global Landslide Catalog (GLC), a worldwide record of recently rainfall-triggered landslides. The extent and composition of this database has been affected by the limits of media search tools and available staffing. Citizen scientists could expand the effort exponentially, as well as diversify the knowledge base of the research team. In order to enable this collaboration the NASA Center for Climate Simulation has created a GIS portal for viewing, editing, and managing the GLC. The data is also exposed through a Rest API, for easy incorporation into geospatial websites by third parties. Future developments may include the ability to store polygons delineating large landslides, digitization from recent satellite imagery, and the establishment of a community for international landslide research that is open to both lay and academic users.
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Size distributions and failure initiation of submarine and subaerial landslides
ten Brink, Uri S.; Barkan, R.; Andrews, B.D.; Chaytor, J.D.
2009-01-01
Landslides are often viewed together with other natural hazards, such as earthquakes and fires, as phenomena whose size distribution obeys an inverse power law. Inverse power law distributions are the result of additive avalanche processes, in which the final size cannot be predicted at the onset of the disturbance. Volume and area distributions of submarine landslides along the U.S. Atlantic continental slope follow a lognormal distribution and not an inverse power law. Using Monte Carlo simulations, we generated area distributions of submarine landslides that show a characteristic size and with few smaller and larger areas, which can be described well by a lognormal distribution. To generate these distributions we assumed that the area of slope failure depends on earthquake magnitude, i.e., that failure occurs simultaneously over the area affected by horizontal ground shaking, and does not cascade from nucleating points. Furthermore, the downslope movement of displaced sediments does not entrain significant amounts of additional material. Our simulations fit well the area distribution of landslide sources along the Atlantic continental margin, if we assume that the slope has been subjected to earthquakes of magnitude ??? 6.3. Regions of submarine landslides, whose area distributions obey inverse power laws, may be controlled by different generation mechanisms, such as the gradual development of fractures in the headwalls of cliffs. The observation of a large number of small subaerial landslides being triggered by a single earthquake is also compatible with the hypothesis that failure occurs simultaneously in many locations within the area affected by ground shaking. Unlike submarine landslides, which are found on large uniformly-dipping slopes, a single large landslide scarp cannot form on land because of the heterogeneous morphology and short slope distances of tectonically-active subaerial regions. However, for a given earthquake magnitude, the total area
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Experiences from site-specific landslide early warning systems
Michoud, C.; Bazin, S.; Blikra, L. H.; Derron, M.-H.; Jaboyedoff, M.
2013-10-01
Landslide early warning systems (EWSs) have to be implemented in areas with large risk for populations or infrastructures when classical structural remediation measures cannot be set up. This paper aims to gather experiences of existing landslide EWSs, with a special focus on practical requirements (e.g., alarm threshold values have to take into account the smallest detectable signal levels of deployed sensors before being established) and specific issues when dealing with system implementations. Within the framework of the SafeLand European project, a questionnaire was sent to about one-hundred institutions in charge of landslide management. Finally, we interpreted answers from experts belonging to 14 operational units related to 23 monitored landslides. Although no standard requirements exist for designing and operating EWSs, this review highlights some key elements, such as the importance of pre-investigation work, the redundancy and robustness of monitoring systems, the establishment of different scenarios adapted to gradual increasing of alert levels, and the necessity of confidence and trust between local populations and scientists. Moreover, it also confirms the need to improve our capabilities for failure forecasting, monitoring techniques and integration of water processes into landslide conceptual models.
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Controls on slow-moving landslides revealed by satellite and airborne InSAR
Handwerger, Alexander L.; Fielding, Eric J.
2017-04-01
Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains
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Characteristic and Behavior of Rainfall Induced Landslides in Java Island, Indonesia : an Overview
Christanto, N.; Hadmoko, D. S.; Westen, C. J.; Lavigne, F.; Sartohadi, J.; Setiawan, M. A.
2009-04-01
Landslides are important natural hazards occurring on mountainous area situated in the wet tropical climate like in Java, Indonesia. As a central of economic and government activity, Java become the most populated island in Indonesia and is increasing every year. This condition create population more vulnerable to hazard. Java is populated by 120 million inhabitants or equivalent with 60% of Indonesian population in only 6,9% of the total surface of Indonesia. Due to its geological setting, its topographical characteristics, and its climatic characteristics, Java is the most exposed regions to landslide hazard and closely related to several factors: (1) located on a subduction zone, 60% of Java is mountainous, with volcano-tectonic mountain chains and 36 active volcanoes out of the 129 in Indonesia, and these volcanic materials are intensively weathered (2) Java is under a humid tropical climate associated with heavy rainfall during the rainy season from October to April. On top of these "natural" conditions, the human activity is an additional factor of landslide occurrence, driven by a high demographic density The purpose of this paper was to collect and analyze spatial and temporal data concerning landslide hazard for the period 1981-2007 and to evaluate and analyze the characteristic and the behavior of landslide in Java. The results provides a new insight into our understanding of landslide hazard and characteristic in the humid tropics, and a basis for predicting future landslides and assessing related hazards at a regional scale. An overview of characteristic and behavior of landslides in Java is given. The result of this work would be valuable for decision makers and communities in the frame of future landslide risk reduction programs. Landslide inventory data was collected from internal database at the different institutions. The result is then georefenced. The temporal changes of landslide activities was done by examining the changes in number and
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Regional rainfall thresholds for landslide occurrence using a centenary database
Vaz, Teresa; Luís Zêzere, José; Pereira, Susana; Cruz Oliveira, Sérgio; Garcia, Ricardo A. C.; Quaresma, Ivânia
2018-04-01
This work proposes a comprehensive method to assess rainfall thresholds for landslide initiation using a centenary landslide database associated with a single centenary daily rainfall data set. The method is applied to the Lisbon region and includes the rainfall return period analysis that was used to identify the critical rainfall combination (cumulated rainfall duration) related to each landslide event. The spatial representativeness of the reference rain gauge is evaluated and the rainfall thresholds are assessed and calibrated using the receiver operating characteristic (ROC) metrics. Results show that landslide events located up to 10 km from the rain gauge can be used to calculate the rainfall thresholds in the study area; however, these thresholds may be used with acceptable confidence up to 50 km from the rain gauge. The rainfall thresholds obtained using linear and potential regression perform well in ROC metrics. However, the intermediate thresholds based on the probability of landslide events established in the zone between the lower-limit threshold and the upper-limit threshold are much more informative as they indicate the probability of landslide event occurrence given rainfall exceeding the threshold. This information can be easily included in landslide early warning systems, especially when combined with the probability of rainfall above each threshold.
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Spatial prediction of landslide hazard using discriminant analysis and GIS
Peter V. Gorsevski; Paul Gessler; Randy B. Foltz
2000-01-01
Environmental attributes relevant for spatial prediction of landslides triggered by rain and snowmelt events were derived from digital elevation model (DEM). Those data in conjunction with statistics and geographic information system (GIS) provided a detailed basis for spatial prediction of landslide hazard. The spatial prediction of landslide hazard in this paper is...
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The inventorying and mapping of landslide potential in Manado – Indonesia
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Mithel Kumajas
2016-05-01
Full Text Available Landslide constitutes a frequent problem occurs in Manado. It happens for many times from year to year and brings both material disadvantage and casualty. The way and hilly topography of Manado, unstabel geological condition, high rainfall, and the improper land use are assumed to be the trigger for the problem. The objective of this study is to inventory and map landslide potential area as well as to design the preventive plan. Mapping method employs spatial approach by using land unit as the analysis unit. The technique of analysis applies the assistance of GIS with its ArcView soft ware. The result of mapping shows that the level landslide potential from potential until very potential category in Manado is 1.815,72 Ha; potential is 1282,10 ha and very potential category is 533,62 ha. The faktors cause the landslide comprise of rocky declivity, high rainfall, and the condition of stone as well as the unstabel and porous soil. The existence of Cesar zone extends to the center of the city and the use of settlement land located in improper zone become the trigger that quicken the occurrence of landslide. The strategy implemented to manage the landslide potential area can be carried out through 1 law enforcement in relation to city lay out, 2 landslide prevention through civil and vegetative technique, 3 the improvement of social consciousness of the danger of landslide disaster and the attempt for social empowerment, and 4 the provision of the landslide potential danger map as the ground for policy making in the effort to manage the landslide disaster.
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Non-susceptible landslide areas in Italy and in the Mediterranean region
Marchesini, I.; Ardizzone, F.; Alvioli, M.; Rossi, M.; Guzzetti, F.
2014-08-01
We used landslide information for 13 study areas in Italy and morphometric information obtained from the 3-arcseconds shuttle radar topography mission digital elevation model (SRTM DEM) to determine areas where landslide susceptibility is expected to be negligible in Italy and in the landmasses surrounding the Mediterranean Sea. The morphometric information consisted of the local terrain slope which was computed in a square 3 × 3-cell moving window, and in the regional relative relief computed in a circular 15 × 15-cell moving window. We tested three different models to classify the "non-susceptible" landslide areas, including a linear model (LNR), a quantile linear model (QLR), and a quantile, non-linear model (QNL). We tested the performance of the three models using independent landslide information presented by the Italian Landslide Inventory (Inventario Fenomeni Franosi in Italia - IFFI). Best results were obtained using the QNL model. The corresponding zonation of non-susceptible landslide areas was intersected in a geographic information system (GIS) with geographical census data for Italy. The result determined that 57.5% of the population of Italy (in 2001) was located in areas where landslide susceptibility is expected to be negligible. We applied the QNL model to the landmasses surrounding the Mediterranean Sea, and we tested the synoptic non-susceptibility zonation using independent landslide information for three study areas in Spain. Results showed that the QNL model was capable of determining where landslide susceptibility is expected to be negligible in the validation areas in Spain. We expect our results to be applicable in similar study areas, facilitating the identification of non-susceptible landslide areas, at the synoptic scale.
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Landslide Susceptibility Assessment Using Frequency Ratio Technique with Iterative Random Sampling
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Hyun-Joo Oh
2017-01-01
Full Text Available This paper assesses the performance of the landslide susceptibility analysis using frequency ratio (FR with an iterative random sampling. A pair of before-and-after digital aerial photographs with 50 cm spatial resolution was used to detect landslide occurrences in Yongin area, Korea. Iterative random sampling was run ten times in total and each time it was applied to the training and validation datasets. Thirteen landslide causative factors were derived from the topographic, soil, forest, and geological maps. The FR scores were calculated from the causative factors and training occurrences repeatedly ten times. The ten landslide susceptibility maps were obtained from the integration of causative factors that assigned FR scores. The landslide susceptibility maps were validated by using each validation dataset. The FR method achieved susceptibility accuracies from 89.48% to 93.21%. And the landslide susceptibility accuracy of the FR method is higher than 89%. Moreover, the ten times iterative FR modeling may contribute to a better understanding of a regularized relationship between the causative factors and landslide susceptibility. This makes it possible to incorporate knowledge-driven considerations of the causative factors into the landslide susceptibility analysis and also be extensively used to other areas.
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Modeling Accumulated Volume of Landslides Using Remote Sensing and DTM Data
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Zhengchao Chen
2014-02-01
Full Text Available Landslides, like other natural hazards, such as avalanches, floods, and debris flows, may result in a lot of property damage and human casualties. The volume of landslide deposits is a key parameter for landslide studies and disaster relief. Using remote sensing and digital terrain model (DTM data, this paper analyzes errors that can occur in calculating landslide volumes using conventional models. To improve existing models, the mechanisms and laws governing the material deposited by landslides are studied and then the mass balance principle and mass balance line are defined. Based on these ideas, a novel and improved model (Mass Balance Model, MBM is proposed. By using a parameter called the “height adaptor”, MBM translates the volume calculation into an automatic search for the mass balance line within the scope of the landslide. Due to the use of mass balance constraints and the height adaptor, MBM is much more effective and reliable. A test of MBM was carried out for the case of a typical landslide, triggered by the Wenchuan Earthquake of 12 May 2008.
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Landslide hazards and systems analysis: A Central European perspective
Klose, Martin; Damm, Bodo; Kreuzer, Thomas
2016-04-01
Part of the problem with assessing landslide hazards is to understand the variable settings in which they occur. There is growing consensus that hazard assessments require integrated approaches that take account of the coupled human-environment system. Here we provide a synthesis of societal exposure and vulnerability to landslide hazards, review innovative approaches to hazard identification, and lay a focus on hazard assessment, while presenting the results of historical case studies and a landslide time series for Germany. The findings add to a growing body of literature that recognizes societal exposure and vulnerability as a complex system of hazard interactions that evolves over time as a function of social change and development. We therefore propose to expand hazard assessments by the framework and concepts of systems analysis (e.g., Liu et al., 2007) Results so far have been promising in ways that illustrate the importance of feedbacks, thresholds, surprises, and time lags in the evolution of landslide hazard and risk. In densely populated areas of Central Europe, landslides often occur in urbanized landscapes or on engineered slopes that had been transformed or created intentionally by human activity, sometimes even centuries ago. The example of Germany enables to correlate the causes and effects of recent landslides with the historical transition of urbanization to urban sprawl, ongoing demographic change, and some chronic problems of industrialized countries today, including ageing infrastructures or rising government debts. In large parts of rural Germany, the combination of ageing infrastructures, population loss, and increasing budget deficits starts to erode historical resilience gains, which brings especially small communities to a tipping point in their efforts to risk reduction. While struggling with budget deficits and demographic change, these communities are required to maintain ageing infrastructures that are particularly vulnerable to
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Geological control of earthquake induced landslide in El Salvador
Tsige Aga, Meaza
2010-05-01
Geological control of earthquake induced landslides in El Salvador. M., Tsige(1), I., Garcia-Flórez(1), R., Mateos(2) (1)Universidad Complutense de Madrid, Facultad de Geología, Madrid, Spain, (meaza@geo.ucm.es) (2)IGME, Mallorca El Salvador is located at one of the most seismically active areas en Central America, and suffered severe damage and loss of life in historical and recent earthquakes, as a consequence of earthquake induced landslides. The most common landslides were shallow disrupted soil-slides on steep slopes and were particularly dense in the central part of the country. Most of them are cited in the recent mechanically weak volcanic pyroclastic deposits known as "Tierra Blanca" and "Tierra Color Café" which are prone to seismic wave amplification and are supposed to have contributed to the triggering of some of the hundreds of landslides related to the 2001 (Mw = 7.6 and Mw = 6.7), seismic events. The earthquakes also triggered numerous deep large scale landslides responsible for the enormous devastation of villages and towns and are the source for the current high seismic hazard as well. Many of these landslides are located at distances more than 50 and 100 km from the focal distance, although some of them occurred at near field. Until now there has been little effort to explain the causes and concentration of the deep large-scale landslides especially their distribution, failure mechanism and post-rapture behavior of the landslide mass (long run-out). It has been done a field investigation of landslides, geological materiales and interpretation of aerial photographs taken before and after the two 2001 (Mw= 7.6 and Mw= 6.7) El Salvador earthquakes. The result of the study showed that most of the large-scale landslides occured as coherent block slides with the sliding surface parallel to a pre-existing fractures and fault planes (La Leona, Barriolera, El Desague, Jiboa landslides). Besides that the pre-existing fractures are weak zones controlling
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High-speed landslide mechanism extracted from long-period surface waves
Zhao, Juan
2016-04-01
Long-period seismic signals gathered at stations far from landslide area can be used to recover the landslide source force applied on ground during the rapid sliding process. This force history is helpful to improve our ability to deduce the characteristics of the event as well as the dynamic properties of bulk motion. We use source mechanism inversion to analyse two different large landslides. Seismic waves generated by these two events have been recorded respectively by more than 5 stations, with the distance range from 69km to 1325km. The first event is the sudden failure happened at Qianjiangping village (30.97°N, 110.61°E) on 13 July 2003, on the bank of the Qinggan river. The landslide flow brought about 20 million cubic meters rock and soil masses right into the river in a short time. It moved about 250 meters in the main sliding direction of S45°E before stopped by the opposite bank. It is a typical reservoir landslide, which has been compared to the 1963 Vaiont landslide in Italy. The other event is the Xiaolin (120.64°E; 23.16°N) deep-seated landslide, located in southwestern Taiwan and had volume of about 27 million cubic meters. The landslide moved in the westward direction, divided into two streams at about the middle of the run-out, because there had been a small ridge and two valleys extended from the west side of the ridge. The deposit spreading length of this landslide is about 2300 meters. We discuss the different characteristics of the two events in both geological structure and movement mode based on the field survey. Then we show that those differences are also revealed by the source force-time functions from inversion.
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Sentinel-2 for rapid operational landslide inventory mapping
Stumpf, André; Marc, Odin; Malet, Jean-Philippe; Michea, David
2017-04-01
Landslide inventory mapping after major triggering events such as heavy rainfalls or earthquakes is crucial for disaster response, the assessment of hazards, and the quantification of sediment budgets and empirical scaling laws. Numerous studies have already demonstrated the utility of very-high resolution satellite and aerial images for the elaboration of inventories based on semi-automatic methods or visual image interpretation. Nevertheless, such semi-automatic methods are rarely used in an operational context after major triggering events; this is partly due to access limitations on the required input datasets (i.e. VHR satellite images) and to the absence of dedicated services (i.e. processing chain) available for the landslide community. Several on-going initiatives allow to overcome these limitations. First, from a data perspective, the launch of the Sentinel-2 mission offers opportunities for the design of an operational service that can be deployed for landslide inventory mapping at any time and everywhere on the globe. Second, from an implementation perspective, the Geohazards Exploitation Platform (GEP) of the European Space Agency (ESA) allows the integration and diffusion of on-line processing algorithms in a high computing performance environment. Third, from a community perspective, the recently launched Landslide Pilot of the Committee on Earth Observation Satellites (CEOS), has targeted the take-off of such service as a main objective for the landslide community. Within this context, this study targets the development of a largely automatic, supervised image processing chain for landslide inventory mapping from bi-temporal (before and after a given event) Sentinel-2 optical images. The processing chain combines change detection methods, image segmentation, higher-level image features (e.g. texture, shape) and topographic variables. Based on a few representative examples provided by a human operator, a machine learning model is trained and
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Directory of Open Access Journals (Sweden)
B. Casson
2005-01-01
Full Text Available Landslide activity is partly controlled by the geometry of the slip surface. This activity is traduced at the surface by displacements and topographic variations. Consequently, multi-temporal remote sensing images can be used in order to characterize the geometry of landslide slip surface and its spatial and temporal evolution. Differential Digital Elevation Models (DEMs are obtained by subtracting two DEMs of different years. A method of multi-temporal images correlation allows to generate displacement maps that can be interpreted in terms of velocity and direction of movements. These data are then used to characterize qualitatively the geometry of the slip surface of the la Clapière landslide (French Southern Alps. Distribution of displacement vectors and of topographic variations are in accordance with a curved slip surface, characterizing a preferential rotational behaviour of this landslide. On the other hand, a spatial and temporal evolution of the geometry of the slip surface is pointed out. Indeed, a propagation of the slip surface under the Iglière bar, in the W part of the landslide, is suspected and can be linked to the acceleration of the landslide in 1987. This study shows the high potential of multi-temporal remote sensing images for slip surface characterization. Although this method could not replace in situ investigations, it can really help to well distribute geophysical profiles or boreholes on unstable areas.
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Assessment of landslide risk using gis and statistical methods in kysuce region
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Barančoková Mária
2014-03-01
Full Text Available The landslide susceptibility was assessed based on multivariation analysis. The input parameters were represented by lithology, land use, slope inclination and average annual precipitation. These parameters were evaluated as independent variables, and the existing landslides as dependent variables. The individual input parameters were reclassified and spatially adjusted. Spatial analysis resulted in 15 988 combinations of input parameters representing the homogeneous condition unit (HCU . Based on the landslide density within individual units, the HCU polygons have been classified according to landslide risk into stable, conditionally stable, conditionally stable and unstable (subdivided into low, medium and high landslide risk. A total of 2002 HCU s were affected by landslides, and the remaining 13 986 were not affected. The total HCU area affected by landslides is about 156.92 km2 (20.1%. Stable areas covered 623.01 km2 (79.8%, and conditionally stable areas covered 228.77 km2 (29.33% out of this area. Unstable areas were divided into three levels of landslide risk - low, medium and high risk. An area of 111.19 km2 (14.3% represents low landslide risk, medium risk 29.7 km2 (3.8% and 16.01 km2 (2% represents high risk. Since Zlín Formation lithological unit covers approximately one-third of the study area, it also influences the overall landslide risk assessment. This lithological formation covers the largest area within all landslide risk classes as well as in conditionally stable areas. The most frequent slope class was in the range of 14-19. The higher susceptibility of Zlín Formation to landslides is caused mainly by different geomorphological value of claystone and sandstone sequence. The higher share of claystone results in higher susceptibility of this formation to exogenous degradation processes.
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Earthquake-triggered landslides in southwest China
X. L. Chen; Q. Zhou; H. Ran; R. Dong
2012-01-01
Southwest China is located in the southeastern margin of the Tibetan Plateau and it is a region of high seismic activity. Historically, strong earthquakes that occurred here usually generated lots of landslides and brought destructive damages. This paper introduces several earthquake-triggered landslide events in this region and describes their characteristics. Also, the historical data of earthquakes with a magnitude of 7.0 or greater, having occurred in this region, is col...
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Samodra, G.; Chen, G.; Sartohadi, J.; Kasama, K.
2018-04-01
This paper proposes an approach for landslide inventory mapping considering actual conditions in Indonesia. No satisfactory landslide database exists. What exists is inadequate, focusing, on data response, rather than on pre-disaster preparedness and planning. The humid tropical climate also leads a rapid vegetation growth so past landslides signatures are covered by vegetation or dismantled by erosion process. Generating landslide inventory using standard techniques still seems difficult. A catalog of disasters from local government (village level) was used as a basis of participatory landslide inventory mapping. Eyewitnesses or landslide disaster victims were asked to participate in the reconstruction of past landslides. Field investigation focusing on active participation from communities with the use of an innovative technology was used to verify the landslide events recorded in the disaster catalog. Statistical analysis was also used to obtain the necessary relationships between geometric measurements, including the height of the slope and length of run out, area and volume of displaced materials, the probability distributions of landslide area and volume, and mobilization rate. The result shows that run out distance is proportional to the height of the slope. The frequency distribution calculated by using non-cumulative distribution empirically exhibits a power law (fractal statistic) even though rollover can also be found in the dataset. This cannot be the result of the censoring effect or incompleteness of the data because the landslide inventory dataset can be classified as having complete data or nearly complete data. The so-called participatory landslide inventory mapping method is expected to solve the difficulties of landslide inventory mapping and can be applied to support pre-disaster planning and preparedness action to reduce the landslide disaster risk in Indonesia. It may also supplement the usually incomplete data in a typical landslide inventory.
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Directory of Open Access Journals (Sweden)
Wolfgang Wagner
2012-05-01
Full Text Available Predicting the spatial and temporal occurrence of rainfall triggered landslides represents an important scientific and operational issue due to the high threat that they pose to human life and property. This study investigates the relationship between rainfall, soil moisture conditions and landslide movement by using recorded movements of a rock slope located in central Italy, the Torgiovannetto landslide. This landslide is a very large rock slide, threatening county and state roads. Data acquired by a network of extensometers and a meteorological station clearly indicate that the movements of the unstable wedge, first detected in 2003, are still proceeding and the alternate phases of quiescence and reactivation are associated with rainfall patterns. By using a multiple linear regression approach, the opening of the tension cracks (as recorded by the extensometers as a function of rainfall and soil moisture conditions prior the occurrence of rainfall, are predicted for the period 2007–2009. Specifically, soil moisture indicators are obtained through the Soil Water Index, SWI, a product derived by the Advanced SCATterometer (ASCAT on board the MetOp (Meteorological Operational satellite and by an Antecedent Precipitation Index, API. Results indicate that the regression performance (in terms of correlation coefficient, r significantly enhances if an indicator of the soil moisture conditions is included. Specifically, r is equal to 0.40 when only rainfall is used as a predictor variable and increases to r = 0.68 and r = 0.85 if the API and the SWI are used respectively. Therefore, the coarse spatial resolution (25 km of satellite data notwithstanding, the ASCAT SWI is found to be very useful for the prediction of landslide movements on a local scale. These findings, although valid for a specific area, present new opportunities for the effective use of satellite-derived soil moisture estimates to improve landslide forecasting.
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COMPARISON of FUZZY-BASED MODELS in LANDSLIDE HAZARD MAPPING
Directory of Open Access Journals (Sweden)
N. Mijani
2017-09-01
Full Text Available Landslide is one of the main geomorphic processes which effects on the development of prospect in mountainous areas and causes disastrous accidents. Landslide is an event which has different uncertain criteria such as altitude, slope, aspect, land use, vegetation density, precipitation, distance from the river and distance from the road network. This research aims to compare and evaluate different fuzzy-based models including Fuzzy Analytic Hierarchy Process (Fuzzy-AHP, Fuzzy Gamma and Fuzzy-OR. The main contribution of this paper reveals to the comprehensive criteria causing landslide hazard considering their uncertainties and comparison of different fuzzy-based models. The quantify of evaluation process are calculated by Density Ratio (DR and Quality Sum (QS. The proposed methodology implemented in Sari, one of the city of Iran which has faced multiple landslide accidents in recent years due to the particular environmental conditions. The achieved results of accuracy assessment based on the quantifier strated that Fuzzy-AHP model has higher accuracy compared to other two models in landslide hazard zonation. Accuracy of zoning obtained from Fuzzy-AHP model is respectively 0.92 and 0.45 based on method Precision (P and QS indicators. Based on obtained landslide hazard maps, Fuzzy-AHP, Fuzzy Gamma and Fuzzy-OR respectively cover 13, 26 and 35 percent of the study area with a very high risk level. Based on these findings, fuzzy-AHP model has been selected as the most appropriate method of zoning landslide in the city of Sari and the Fuzzy-gamma method with a minor difference is in the second order.
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A Critical Review of Landslide Failure Mechanisms
Stead, D.; Wolter, A.; Clague, J. J.
2011-12-01
During the last ten years several comprehensive geotechnical studies have been completed on major historic landslides including Randa in Switzerland, Frank in Canada, Aknes in Norway, La Clapiere in France and Vaiont in Italy. In addition, numerous researchers have documented deep-seated gravitational deformations and a wide variety of large prehistoric rock slope failures. The information provided by these studies is evidence of the significant advances made in our ability to map, monitor and model landslides. Over the same period, the mining industry has developed large open pits with slope heights exceeding 1000 m that provide important analogues to high mountain slopes. In this paper we analyse data from the literature to illustrate the importance of brittle fracture, 3D controls, anisotropy, overburden stress, geomorphic processes, groundwater and temperature in major landslides and provide some indicators as to the research required to further understand the complexity of rock slope failure mechanisms. The nature of the landslide failure surface has received inadequate attention in the past, with failure surfaces typically considered in 2D and simulated as discrete, smooth and often planar features. Current work shows that failure surfaces are inherently three-dimensional and have much structural variability across the area of the landslide scarp, reflecting complex structural histories. Such anisotropy and variations may result in multiple events or distinct blocks that move at different rates. Just as most failure surfaces vary spatially, they may also change with depth and thus should more realistically be considered failure zones rather than discrete surfaces. The increasing recognition of the importance of step-path failures, internal dilation and brittle fracture are indicative of the complexity in slope failure surfaces. Related to the variation in failure surface characteristics is the importance of 3D rotational displacements and both the
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Landslide hazard in the Nebrodi Mountains (Northeastern Sicily)
Cubito, A.; Ferrara, V.; Pappalardo, G.
2005-03-01
The eastern sector of the Nebrodi Mountains (NE Sicily), a part of the Apenninic-Maghrebian orogenic chain, is characterized by an high landslide hazard. The village of S. Domenica Vittoria, which lies in the area, has been particularly affected by various landslide phenomena, with resulting damage to buildings and infrastructure. The rocks outcropping in the area belong to the Cretaceous Monte Soro Flysch; they consist of an alternation of argillaceous and calcareous beds at the base and argillaceous and quartzarenitic beds at the top. The lithotechnical characteristics of the formation and the steepness of the slopes in the area lead to an elevated instability, as testified by the widespread occurrence of sub-vertical arcuate cliffs (landslide scarps) and sub-horizontal areas (landslide terraces), typical of a landslide-controlled morphology. From a kinematics point of view, the observed phenomena can be referred to multiple rotational slides, flows, and complex landslides, often with a retrogressive development and enlargement. Triggering causes lie principally in the intense rainfalls that determine the decay of the geomechanical properties of the terrain and supply discontinuos groundwater circulation that is evident in seasonal springs. Human activity, such as the construction of roads and buildings on steep slopes and dispersal of water from supply systems and sewers has a significant impact as well. Due to the instability of the area, expansion of the village, which is already limited by the morphological conditions, is made difficult by the high hazard level, especially in the areas at higher elevations, where the principal landslide scarps are located, and even more on the rims of the scarps. Considering the high hazard level, S. Domenica Vittoria has been inserted by the National Geological Service among the sites in Sicily to be monitored by means of a GPS network. The survey carried out along the entire slope hosting the village has furnished the base
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Pourghasemi, Hamid Reza; Rossi, Mauro
2017-10-01
Landslides are identified as one of the most important natural hazards in many areas throughout the world. The essential purpose of this study is to compare general linear model (GLM), general additive model (GAM), multivariate adaptive regression spline (MARS), and modified analytical hierarchy process (M-AHP) models and assessment of their performances for landslide susceptibility modeling in the west of Mazandaran Province, Iran. First, landslides were identified by interpreting aerial photographs, and extensive field works. In total, 153 landslides were identified in the study area. Among these, 105 landslides were randomly selected as training data (i.e. used in the models training) and the remaining 48 (30 %) cases were used for the validation (i.e. used in the models validation). Afterward, based on a deep literature review on 220 scientific papers (period between 2005 and 2012), eleven conditioning factors including lithology, land use, distance from rivers, distance from roads, distance from faults, slope angle, slope aspect, altitude, topographic wetness index (TWI), plan curvature, and profile curvature were selected. The Certainty Factor (CF) model was used for managing uncertainty in rule-based systems and evaluation of the correlation between the dependent (landslides) and independent variables. Finally, the landslide susceptibility zonation was produced using GLM, GAM, MARS, and M-AHP models. For evaluation of the models, the area under the curve (AUC) method was used and both success and prediction rate curves were calculated. The evaluation of models for GLM, GAM, and MARS showed 90.50, 88.90, and 82.10 % for training data and 77.52, 70.49, and 78.17 % for validation data, respectively. Furthermore, The AUC value of the produced landslide susceptibility map using M-AHP showed a training value of 77.82 % and validation value of 82.77 % accuracy. Based on the overall assessments, the proposed approaches showed reasonable results for landslide
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Liu, Yong; Qin, Zhimeng; Hu, Baodan; Feng, Shuai
2018-04-01
Stability analysis is of great significance to landslide hazard prevention, especially the dynamic stability. However, many existing stability analysis methods are difficult to analyse the continuous landslide stability and its changing regularities in a uniform criterion due to the unique landslide geological conditions. Based on the relationship between displacement monitoring data, deformation states and landslide stability, a state fusion entropy method is herein proposed to derive landslide instability through a comprehensive multi-attribute entropy analysis of deformation states, which are defined by a proposed joint clustering method combining K-means and a cloud model. Taking Xintan landslide as the detailed case study, cumulative state fusion entropy presents an obvious increasing trend after the landslide entered accelerative deformation stage and historical maxima match highly with landslide macroscopic deformation behaviours in key time nodes. Reasonable results are also obtained in its application to several other landslides in the Three Gorges Reservoir in China. Combined with field survey, state fusion entropy may serve for assessing landslide stability and judging landslide evolutionary stages.
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Relationship between gullying and landslides within the Barlad Plateau, Romania
Niacsu, Lilian; Ionita, Ion
2016-04-01
Located in the eastern Romania and extending on 8200 km2 the Barlad Plateau is considered the most typical subunit of the Moldavian Plateau. The sedimentary Miocene-Pliocene clay-sandy layers, inter-bedded with shallow sandstone and limestone are gently dipping toward S-SE as homoclinal structure. Land degradation through soil erosion, gullying and landslides represent the most important environmental threat in the region. By using both the classical research methods such as repeated field surveys and mapping, mathematical-statistical processing as well as the present-day methods based on the GIS software it was possible to precisely measure and evaluate the gully erosion rates and triggered landslides during the last two centuries, especially with a very high accuracy since 1960. Results have indicated that the landslide development is strongly controlled by gullying. Generally, by combining the areal growth of both gullying and new landslides within the selected study catchments, it is noticeable that 62 % of the total recent land degradation occurred during the last 55 years, with the remainder pre-1960. In addition, half of the gully areal growth occurred since 1961 but the new triggered landslides amount over three-quarters of the total area under landslides. This asymmetrical distribution reveals that usually a preparing time lag of tens of years is required for triggering landslides by gullying and this pattern depicts the common mechanism for landslide development. Acknowledgements: This work was partly supported by a grant from the Romanian National Authority for Scientific Research, CNDI-UEFISCDI, Project number PN-II-PT-PCCA-2011-3.2-0975.
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Some rapid and long traveled landslides triggered by the May 12, 2008 Sichuan earthquake
Wang, G.; Kamai, T.; Chigira, M.; Wu, X. Y.; Zhang, D. X.
2009-04-01
On May 12, 2008, a 7.9M earthquake struck Sichuan province of China, causing a huge number of death and injuries, and great loss of properties, becoming the most damaging earthquake since the 1976 Tangshan earthquake, in China. The collapse of buildings during the earthquake is the main reason for the casualties. There are a huge number of landslides that had been triggered by this earthquake. Almost all the roads to the mountainous areas had been blocked and many dams were formed by the displaced landslide materials, resulting in great difficulties for the aftershock rescue activities. Also a big portion of the casualties was directly caused by the landslides. The authors had reconnaissance field trips of the landslides, and performed preliminary investigation on some of the catastrophic ones. In this report, four landslides, i.e., Xiejiadian landslide in Pengzhou city, Donghekou landslide and Magongxiang landslide in Qingchuan County, and Niujuangou landslide on the epicenter area of Yingxiu Town, are introduced. The characteristics of deposited landslide masses in Donghekou landslide were investigated by means of a multichannel surface wave technique. Two earthquake recorders were installed at the upper part and deposit area of Donghekou landslide. The seismic responses of different parts of the landslides were monitored, and recorded successfully during the aftershocks that occurred in Qingchuan County on July 24, 2008. Also the drained and undrained dynamic shear behaviors of samples from the landslide areas were examined. Some preliminary analyzing results will be presented in this report.
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Analysis of the 2003 Varunawat Landslide, Uttarkashi, India using Earth Observation data
Vinod Kumar, K.; Lakhera, R. C.; Martha, Tapas R.; Chatterjee, R. S.; Bhattacharya, A.
2008-08-01
Mass movements such as landslides in mountainous terrains are natural degradation processes and one of the most important landscape-building factors. Varunawat Parbat overlooking Uttarkashi town witnessed a series of landslides on 23 September 2003 and the debris slides and rock falls continued for 2 weeks. This landslide complex was triggered due to the incessant rainfall prior to the event, and its occurrence led to the blockage of the pilgrim route to Gangotri (source of the Ganges river) and evacuation of thousands of people to safer places. Though there was no loss of lives due to timely evacuation, heavy losses to the property were reported. High-resolution stereoscopic earth observation data were acquired after the incidence to study the landslide in detail with emphasis on the cause of the landslide and mode of failure. Areas along the road and below the Varunawat foothill region are mapped for landslide risk. It was found that the foothill region of the Varunawat Parbat was highly disturbed by man-made activities and houses are dangerously located below steep slopes. The potential zones for landslides along with the existing active and old landslides are mapped. These areas are critical and their treatment with priority is required in order to minimise further landslide occurrences.
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Landslide susceptibility and risk assessment: specificities for road networks
Pellicani, Roberta; Argentiero, Ilenia; Parisi, Alessandro; Spilotro, Giuseppe
2017-04-01
A regional-scale assessment of landslide susceptibility and risk along the main road corridors crossing the provincial territory of Matera (Basilicata Region, Southern Italy) was carried out. The entire provincial road network extends for about 1,320 km through a territory, of which represents the main connection infrastructure among thirty-one municipalities due to the lack of an efficient integrated transportation system through the whole regional territory. For this reason, the strategic importance of these roads consists in their uniqueness in connecting every urban center with the socio-economic surrounding context. These roads and their vehicular traffic are continuously exposed to instability processes (about the 40% of the total length is disrupted by landslides), characterized both by high intensity and low frequency and by low intensity and high frequency. This last typology, consisting in small shallow landslides, is particularly hazardous for the roads since it is widespread along the road network, its occurrence is connected to rainfalls and determines high vulnerability conditions for the road in terms of interruption of vehicular traffic. A GIS-based heuristic-bivariate statistical predictive model was performed to assess and map the landslide susceptibility in the study area, by using a polynomial function of eight predisposing factors, weighted according to their influence on the landslide phenomena, recognized and collected in an inventory. Susceptibility associated to small shallow phenomena was assessed by using a polynomial function of specific factors, such as slope angle and aspect, lithological outcrops, rainfalls, etc. In absence of detailed input data, the spatial distribution of landslide risk along the road corridors was assessed and mapped using a qualitative hazard-consequence matrix approach, by which risk is obtained by combining hazard categories with consequence classes pairwise in a two-dimensional table or matrix. Landslide
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Recent advances in modeling landslides and debris flows
2015-01-01
Landslides and debris flows belong to the most dangerous natural hazards in many parts of the world. Despite intensive research, these events continue to result in human suffering, property losses, and environmental degradation every year. Better understanding of the mechanisms and processes of landslides and debris flows will help make reliable predictions, develop mitigation strategies and reduce vulnerability of infrastructure. This book presents contributions to the workshop on Recent Developments in the Analysis, Monitoring and Forecast of Landslides and Debris Flow, in Vienna, Austria, September 9, 2013. The contributions cover a broad spectrum of topics from material behavior, physical modelling over numerical simulation to applications and case studies. The workshop is a joint event of three research projects funded by the European Commission within the 7th Framework Program: MUMOLADE (Multiscale modelling of landslides and debris flows, www.mumolade.com), REVENUES (Numerical Analysis of Slopes with V...
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From Urey To The Ocean's Glacial Ph: News From The Boron-11 Paleo-acidimetry.
Zeebe, R. E.; Wolf-Gladrow, D. A.; Bijma, J.
Boron paleo-acidimetry is based on the stable boron isotope composition of foraminiferal shells which has been shown to be a function of seawater pH. It is cur- rently one of the most promising paleo-carbonate chemistry proxies. One important parameter of the proxy is the equilibrium fractionation between the dissolved boron species B(OH)3 and B(OH)- which was calculated to be 19 per mil at 25C by Kak- 4 ihana and Kotaka (1977), based on Urey's theory. The calculated equilibrium frac- tionation, however, depends on the vibrational frequencies of the molecules for which different values have been reported in the literature. We have recalculated the equilib- rium fractionation and find that it may be distinctly different from 19 per mil (this is the bad news). The good news is that - theoretically - the use of 11B as a paleo-pH indicator is not compromised through vital effects in planktonic foraminifera. We de- rive this conclusion by the use of a diffusion-reaction model that calculates pH profiles and 11B values in the vicinity of a foraminifer.
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Long-term Observation of Soil Creep Activity around a Landslide Scar
Rate of sediment infilling into landslide scars by soil creep is needed to estimate the timing of subsequent landslide activity at a particular site. However, knowledge about the spatial distribution of its activity around the landslide scar is scarce. Additionally, there are few...
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Integration of fluvial erosion factors for predicting landslides along meandering rivers
Chen, Yi-chin; Chang, Kang-tsung; Ho, Jui-yi
2015-04-01
River incision and lateral erosion are important geomorphologic processes in mountainous areas of Taiwan. During a typhoon or storm event, the increase of water discharge, flow velocity, and sediment discharge enhances the power of river erosion on channel bank. After the materials on toe of hillslope were removed by river erosion, landslides were triggered at outer meander bends. Although it has been long expected that river erosion can trigger landslide, studies quantifying the effects of river erosion on landslide and the application of river erosion index in landslide prediction are still overlooked. In this study, we investigated the effect of river erosion on landslide in a particular meanders landscape of the Jhoukou River, southern Taiwan. We developed a semi-automatic model to separate meandering lines into several reach segments based on the inflection points and to calculate river erosion indexes, e.g. sinuosity of meander, stream power, and stream order, for each reach segment. This model, then, built the spatial relationship between the reaches and its corresponding hillslopes, of which the toe was eroded by the reach. Based on the spatial relationship, we quantified the correlations between these indexes and landslides triggered by Typhoon Morakot in 2009 to examine the effects of river erosion on landslide. The correlated indexes were then used as landslide predictors in logistic regression model. Results of the study showed that there is no significant correlation between landslide density and meander sinuosity. This may be a result of wider channel dispersing the erosion at a meandering reach. On the other hand, landslide density at concave bank is significantly higher than that at convex bank in the downstream (stream order > 3), but that is almost the same in the upstream (stream order bank. In contrast, river sediment in the downstream is an erosion agent eroding the concave bank laterally, but also depositing on the concave side and protecting
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International Nuclear Information System (INIS)
Aman, S N A; Latif, Z Abd; Pradhan, B
2014-01-01
Landslide occurrence depends on various interrelating factors which consequently initiate to massive mass of soil and rock debris that move downhill due to the gravity action. LiDAR has come with a progressive approach in mitigating landslide by permitting the formation of more accurate DEM compared to other active space borne and airborne remote sensing techniques. The objective of this research is to assess the susceptibility of landslide in Ulu Klang area by investigating the correlation between past landslide events with geo environmental factors. A high resolution LiDAR DEM was constructed to produce topographic attributes such as slope, curvature and aspect. These data were utilized to derive second deliverables of landslide parameters such as topographic wetness index (TWI), surface area ratio (SAR) and stream power index (SPI) as well as NDVI generated from IKONOS imagery. Subsequently, a probabilistic based frequency ratio model was applied to establish the spatial relationship between the landslide locations and each landslide related factor. Factor ratings were summed up to obtain Landslide Susceptibility Index (LSI) to construct the landslide susceptibility map
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Hydrologic Impacts of Landslide Disturbances: Implications for Remobilization and Hazard Persistence
Mirus, Benjamin B.; Smith, Joel B.; Baum, Rex L.
2017-10-01
Landslides typically alter hillslope topography, but may also change the hydrologic connectivity and subsurface water-storage dynamics. In settings where mobile materials are not completely evacuated from steep slopes, influences of landslide disturbances on hillslope hydrology and susceptibility to subsequent failures remain poorly characterized. Since landslides often recur at the site of previous failures, we examine differences between a stable vegetated hillslope (VH) and a recent landslide (LS). These neighboring hillslopes exhibit similar topography and are situated on steep landslide-prone coastal bluffs of glacial deposits along the northeastern shore of Puget Sound, Washington. Our control hillslope, VH, is mantled by a heterogeneous colluvium, supporting a dense forest. In early 2013, our test hillslope, LS, also supported a forest before a landslide substantially altered the topography and disturbed the hillslope. In 2015, we observed a clay-rich landslide deposit at LS with sparse vegetation and limited root reinforcement, soil structures, and macropores. Our characterization of the sites also found matrix porosity and hydraulic conductivity are both lower at LS. Continuous monitoring during 2015-2016 revealed reduced effective precipitation at VH (due to canopy interception), an earlier seasonal transition to near-saturated conditions at LS, and longer persistence of positive pore pressures and slower drainage at LS (both seasonally and between major storm events). These differences, along with episodic, complex slope failures at LS support the hypothesis that, despite a reduced average slope, other disturbances introduced by landsliding may promote the hydrologic conditions leading to slope instability, thus contributing to the persistence of landslide hazards.
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Hydrologic impacts of landslide disturbances: Implications for remobilization and hazard persistence
Mirus, Benjamin B.; Smith, Joel B.; Baum, Rex L.
2017-01-01
Landslides typically alter hillslope topography, but may also change the hydrologic connectivity and subsurface water-storage dynamics. In settings where mobile materials are not completely evacuated from steep slopes, influences of landslide disturbances on hillslope hydrology and susceptibility to subsequent failures remain poorly characterized. Since landslides often recur at the site of previous failures, we examine differences between a stable vegetated hillslope (VH) and a recent landslide (LS). These neighboring hillslopes exhibit similar topography and are situated on steep landslide-prone coastal bluffs of glacial deposits along the northeastern shore of Puget Sound, Washington. Our control hillslope, VH, is mantled by a heterogeneous colluvium, supporting a dense forest. In early 2013, our test hillslope, LS, also supported a forest before a landslide substantially altered the topography and disturbed the hillslope. In 2015, we observed a clay-rich landslide deposit at LS with sparse vegetation and limited root reinforcement, soil structures, and macropores. Our characterization of the sites also found matrix porosity and hydraulic conductivity are both lower at LS. Continuous monitoring during 2015-2016 revealed reduced effective precipitation at VH (due to canopy interception), an earlier seasonal transition to near-saturated conditions at LS, and longer persistence of positive pore pressures and slower drainage at LS (both seasonally and between major storm events). These differences, along with episodic, complex slope failures at LS support the hypothesis that, despite a reduced average slope, other disturbances introduced by landsliding may promote the hydrologic conditions leading to slope instability, thus contributing to the persistence of landslide hazards.
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Landslide hazard assessment : LIFE+IMAGINE project methodology and Liguria region use case
Spizzichino, Daniele; Campo, Valentina; Congi, Maria Pia; Cipolloni, Carlo; Delmonaco, Giuseppe; Guerrieri, Luca; Iadanza, Carla; Leoni, Gabriele; Trigila, Alessandro
2015-04-01
Scope of the work is to present a methodology developed for analysis of potential impacts in areas prone to landslide hazard in the framework of the EC project LIFE+IMAGINE. The project aims to implement a web services-based infrastructure addressed to environmental analysis, that integrates, in its own architecture, specifications and results from INSPIRE, SEIS and GMES. Existing web services has been customized to provide functionalities for supporting environmental integrated management. The implemented infrastructure has been applied to landslide risk scenarios, developed in selected pilot areas, aiming at: i) application of standard procedures to implement a landslide risk analysis; ii) definition of a procedure for assessment of potential environmental impacts, based on a set of indicators to estimate the different exposed elements with their specific vulnerability in the pilot area. The landslide pilot and related scenario are focused at providing a simplified Landslide Risk Assessment (LRA) through: 1) a landslide inventory derived from available historical and recent databases and maps; 2) landslide susceptibility and hazard maps; 3) assessment of exposure and vulnerability on selected typologies of elements at risk; 4) implementation of a landslide risk scenario for different sets of exposed elements 5) development of a use case; 6) definition of guidelines, best practices and production of thematic maps. The LRA has been implemented in Liguria region, Italy, in two different catchment areas located in the Cinque Terre National Park, characterized by a high landslide susceptibility and low resilience. The landslide risk impact analysis has been calibrated taking into account the socio-economic damage caused by landslides triggered by the October 2011 meteorological event. During this event, over 600 landslides were triggered in the selected pilot area. Most of landslides affected the diffuse system of anthropogenic terraces and caused the direct
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Legorreta Paulin, G.; Bursik, M. I.; Contreras, T.
2015-12-01
This poster provides an overview of the on-going research project (Grant PAPIIT # IN102115) from the Institute of Geography at the National Autonomous University of Mexico (UNAM) that seeks to conduct a multi-temporal landslide inventory, produce a landslide susceptibility map, and estimate sediment production by using Geographic Information Systems (GIS). The Río La Carbonera watershed on the southeastern flank of Pico de Orizaba volcano, the highest mountain in Mexico, is selected as a study area. The catchment covers 71.9 km2 with elevations ranging from 1224 to 3643 m a.s.l. and hillslopes between landslides. The methodology encompasses three main stages of analysis to assess landslide hazards: Stage 1 builds a historic landslide inventory. In the study area, an inventory of more than 200 landslides is created from multi-temporal aerial-photo-interpretation and local field surveys to assess landslide distribution. All landslides were digitized into a geographic information system (GIS), and a spatial geo-database of landslides was constructed from standardized GIS datasets. Stage 2 calculates the susceptibility for the watershed. During this stage, (SINMAP using default values) is evaluated. Stage 3 Estimate the potential total material delivered to the main stream drainage channel by all landslides in the catchment. Detailed geometric measurements of individual landslides visited during the field work will be carried out to obtain the landslide area and volume. These measurements revealed an empirical relationship between area and volume that took the form of a power law. This relationship will be used to estimate the potential volume of material delivered to the catchment. The technique and its implementation of each stage in a GIS-based technology is presented and discussed.
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Wu, Chunhung
2016-04-01
Few researches have discussed about the applicability of applying the statistical landslide susceptibility (LS) model for extreme rainfall-induced landslide events. The researches focuses on the comparison and applicability of LS models based on four methods, including landslide ratio-based logistic regression (LRBLR), frequency ratio (FR), weight of evidence (WOE), and instability index (II) methods, in an extreme rainfall-induced landslide cases. The landslide inventory in the Chishan river watershed, Southwestern Taiwan, after 2009 Typhoon Morakot is the main materials in this research. The Chishan river watershed is a tributary watershed of Kaoping river watershed, which is a landslide- and erosion-prone watershed with the annual average suspended load of 3.6×107 MT/yr (ranks 11th in the world). Typhoon Morakot struck Southern Taiwan from Aug. 6-10 in 2009 and dumped nearly 2,000 mm of rainfall in the Chishan river watershed. The 24-hour, 48-hour, and 72-hours accumulated rainfall in the Chishan river watershed exceeded the 200-year return period accumulated rainfall. 2,389 landslide polygons in the Chishan river watershed were extracted from SPOT 5 images after 2009 Typhoon Morakot. The total landslide area is around 33.5 km2, equals to the landslide ratio of 4.1%. The main landslide types based on Varnes' (1978) classification are rotational and translational slides. The two characteristics of extreme rainfall-induced landslide event are dense landslide distribution and large occupation of downslope landslide areas owing to headward erosion and bank erosion in the flooding processes. The area of downslope landslide in the Chishan river watershed after 2009 Typhoon Morakot is 3.2 times higher than that of upslope landslide areas. The prediction accuracy of LS models based on LRBLR, FR, WOE, and II methods have been proven over 70%. The model performance and applicability of four models in a landslide-prone watershed with dense distribution of rainfall
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Landslides susceptibility mapping at Gunung Ciremai National Park
Faizin; Nur, Bambang Azis
2018-02-01
In addition to agriculture, tourism became one of primary economic income for communities around Mount Ciremai, West, Java. Unfortunately, the landscape of West Java has many potential causes to disasters, mainly landslides. Mapping of disaster susceptibility area is needed as a consideration of tourism planning. The study was conducted in Gunung Ciremai National Park, West Java. This paper propose a methodology to map landslides susceptibilities based on spatial data. Using Geographic Information System tools, several environmental parameters such as slope, land use, elevation, and lithology are scored to build a landslide susceptibility map. Then, susceptibility map is overlaid with Utilization Zone.
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TRMM Applications for Rainfall-Induced Landslide Early Warning
Dok, A.; Fukuoka, H.; Hong, Y.
2012-04-01
Early warning system (EWS) is the most effective method in saving lives and reducing property damages resulted from the catastrophic landslides if properly implemented in populated areas of landslide-prone nations. For predicting the occurrence of landslides, it requires examination of empirical relationship between rainfall characteristics and past landslide occurrence. In developed countries like Japan and the US, precipitation is monitored by rain radars and ground-based rain gauge matrix. However, in developing regions like Southeast Asian countries, very limited number of rain gauges is available, and there is no implemented methodology for issuing effective warming of landslides yet. Correspondingly, satellite precipitation monitoring could be therefore a possible and promising solution for launching landslide quasi-real-time early warning system in those countries. It is due to the fact that TMPA (TRMM Multi-satellite Precipitation Analysis) can provides a globally calibration-based sequential scheme for combining precipitation estimates from multiple satellites, and gauge analyses where feasible, at fine scales (3-hourly with 0.25°x0.25° spatial resolution). It is available both after and in quasi-real time, calibrated by TRMM Combined Instrument and TRMM Microwave Imager precipitation product. However, validation of ground based rain gauge and TRMM satellite data in the vulnerable regions is still not yet operative. Snake-line/Critical-line and Soil Water Index (SWI) are used for issuing warning of landslide occurrence in Japan; whereas, Caine criterion is preferable in Europe and western nations. Herewith, it presents rainfall behavior which took place in Beichuan city (located on the 2008 Chinese Wenchuan earthquake fault), Hofu and Shobara cities in Japan where localized heavy rainfall attacked in 2009 and 2010, respectively, from TRMM 3B42RT correlated with ground based rain gauge data. The 1-day rainfall intensity and 15-day cumulative rainfall
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International Nuclear Information System (INIS)
Leitch-Devlin, M.A.; Millar, T.J.; Williams, D.A.
1976-01-01
Infrared observations of the Orion nebula have been interpreted by Rowan-Robinson (1975) to imply the existence of 'giant' grains, radius approximately 10 -2 cm, throughout a volume about a parsec in diameter. Although Rowan-Robinson's model of the nebula has been criticized and the presence of such grains in Orion is disputed, the proposition is accepted, that they exist, and in this paper situations in which giant grains could arise are examined. It is found that, while a giant-grain component to the interstellar grain density may exist, it is difficult to understand how giant grains arise to the extent apparently required by the Orion nebula model. (Auth.)
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Application of an advanced fuzzy logic model for landslide susceptibility analysis
Directory of Open Access Journals (Sweden)
Biswajeet Pradhan
2010-09-01
Full Text Available The aim of this study is to evaluate the susceptibility of landslides at Klang valley area, Malaysia, using a Geographic Information System (GIS and remote sensing. Landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys. Topographical and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. A data derived model (frequency ratio and a knowledge-derived model (fuzzy operator were combined for landslide susceptibility analysis. The nine factors that influence landslide occurrence were extracted from the database and the frequency ratio coefficient for each factor was computed. Using the factors and the identified landslide, the fuzzy membership values were calculated. Then fuzzy algebraic operators were applied to the fuzzy membership values for landslide susceptibility mapping. Finally, the produced map was verified by comparing with existing landslide locations for calculating prediction accuracy. Among the fuzzy operators, in the case in which the gamma operator (l = 0.8 showed the best accuracy (91% while the case in which the fuzzy algebraic product was applied showed the worst accuracy (79%.
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An Improved Information Value Model Based on Gray Clustering for Landslide Susceptibility Mapping
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Qianqian Ba
2017-01-01
Full Text Available Landslides, as geological hazards, cause significant casualties and economic losses. Therefore, it is necessary to identify areas prone to landslides for prevention work. This paper proposes an improved information value model based on gray clustering (IVM-GC for landslide susceptibility mapping. This method uses the information value derived from an information value model to achieve susceptibility classification and weight determination of landslide predisposing factors and, hence, obtain the landslide susceptibility of each study unit based on the clustering analysis. Using a landslide inventory of Chongqing, China, which contains 8435 landslides, three landslide susceptibility maps were generated based on the common information value model (IVM, an information value model improved by an analytic hierarchy process (IVM-AHP and our new improved model. Approximately 70% (5905 of the inventory landslides were used to generate the susceptibility maps, while the remaining 30% (2530 were used to validate the results. The training accuracies of the IVM, IVM-AHP and IVM-GC were 81.8%, 78.7% and 85.2%, respectively, and the prediction accuracies were 82.0%, 78.7% and 85.4%, respectively. The results demonstrate that all three methods perform well in evaluating landslide susceptibility. Among them, IVM-GC has the best performance.
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An Assessment of Monsoon Triggered Landslides in Western Nepal
Sudan Acharya, Madhu
2010-05-01
Due to heavy monsoon rain, rugged topography and very young mountains, frequent slope failures and soil erosion are very common in Nepal but in most of cases the natural slopes are disturbed by men to construct a road through it and the situation further aggravated by the Monsoon rain. Summer usually tests the disaster response capacity of Nepal, when the monsoons trigger water induced disasters. This year Nepal's Western regions were most severely affected by floods and landslides. Every year, sadly, it is the same story of mostly poor people living in remote villages succumbing to landslides and flooding and those who survive facing hardships brought on by the disaster. The tail end of the monsoon in October has triggered flood and landslides in Nepal which affected a total of 14 districts in the mid and far-west regions, of which Kailali, Bardiya, Banke, Dadeldhura, Accham and Kanchapur district are most affected. The affected areas are geographically scattered and remote, and are therefore difficult to access. In this year (2009), flood and landslides have claimed 62 lives, affecting more than 152,000 individuals from 27,000 families. More than 4,000 families are displaced and are taking shelter in schools, open space and forest areas with no protection from the external elements. In the above context the prevention and mitigation measures for landslides is a great challenge for Nepal. Nepal has been investing its huge amount of resources to stabilize landslides and roadside slope failures, still then it has become unmanageable during Monsoon time. Considering the above facts, an assessment of landslides which were occurred during the Monsoon (July-October 2009), along Khodpe - Jhota - Chainpur road in far western region of Nepal has been carried out based on the field observation of various landslides. The paper presents the causes and mechanisms of failures of different landslides which are mostly triggered by Monsoon rain. It also suggests some low cost
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Erosion patterns produced by the paleo Haizishan ice cap, SE Tibetan Plateau
Fu, P.; Stroeven, A. P.; Harbor, J.; Hättestrand, C.; Heyman, J.; Caffee, M. W.
2017-12-01
Erosion is a primary driver of landscape evolution, topographic relief production, geochemical cycles, and climate change. Combining in situ 10Be and 26Al exposure age dating, geomorphological mapping, and field investigations, we examine glacial erosion patterns of the almost 4,000 km2 paleo Haizishan ice cap on the southeastern Tibetan Plateau. Our results show that ice caps on the low relief Haizishan Plateau produced a zonal pattern of landscape modification. In locations where apparent exposure ages on bedrock are consistent with the last deglaciation, complete resetting of the cosmogenic exposure age clock indicates glacial erosion of at least a few meters. However, older apparent exposure ages on bedrock in areas known to have been covered by the paleo ice cap during the Last Glacial Maximum indicate inheritance and thus limited glacial erosion. Inferred surface exposure ages from cosmogenic depth profiles through two saprolites vary from resetting and thus saprolite profile truncation to nuclide inheritance indicating limited erosion. Finally, significant nuclide inheritance in river sand samples from basins on the scoured plateau surface also indicate limited glacial erosion during the last glaciation. Hence, for the first time, our study shows clear evidence of preservation under non-erosive ice on the Tibetan Plateau. As patterns of glacial erosion intensity are largely driven by the basal thermal regime, our results confirm earlier inferences from geomorphology for a concentric basal thermal pattern for the paleo Haizishan ice cap during the LGM.
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Frictional velocity-weakening in landslides on Earth and on other planetary bodies.
Lucas, Antoine; Mangeney, Anne; Ampuero, Jean Paul
2014-03-04
One of the ultimate goals in landslide hazard assessment is to predict maximum landslide extension and velocity. Despite much work, the physical processes governing energy dissipation during these natural granular flows remain uncertain. Field observations show that large landslides travel over unexpectedly long distances, suggesting low dissipation. Numerical simulations of landslides require a small friction coefficient to reproduce the extension of their deposits. Here, based on analytical and numerical solutions for granular flows constrained by remote-sensing observations, we develop a consistent method to estimate the effective friction coefficient of landslides. This method uses a constant basal friction coefficient that reproduces the first-order landslide properties. We show that friction decreases with increasing volume or, more fundamentally, with increasing sliding velocity. Inspired by frictional weakening mechanisms thought to operate during earthquakes, we propose an empirical velocity-weakening friction law under a unifying phenomenological framework applicable to small and large landslides observed on Earth and beyond.
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Regional landslide hazard assessment in a deep uncertain future
Almeida, Susana; Holcombe, Liz; Pianosi, Francesca; Wagener, Thorsten
2017-04-01
Landslides have many negative economic and societal impacts, including the potential for significant loss of life and damage to infrastructure. These risks are likely to be exacerbated in the future by a combination of climatic and socio-economic factors. Climate change, for example, is expected to increase the occurrence of rainfall-triggered landslides, because a warmer atmosphere tends to produce more high intensity rainfall events. Prediction of future changes in rainfall, however, is subject to high levels of uncertainty, making it challenging for decision-makers to identify the areas and populations that are most vulnerable to landslide hazards. In this study, we demonstrate how a physically-based model - the Combined Hydrology and Stability Model (CHASM) - can be used together with Global Sensitivity Analysis (GSA) to explore the underlying factors controlling the spatial distribution of landslide risks across a regional landscape, while also accounting for deep uncertainty around future rainfall conditions. We demonstrate how GSA can used to analyse CHASM which in turn represents the spatial variability of hillslope characteristics in the study region, while accounting for other uncertainties. Results are presented in the form of landslide hazard maps, utilising high-resolution digital elevation datasets for a case study in St Lucia in the Caribbean. Our findings about spatial landslide hazard drivers have important implications for data collection approaches and for long-term decision-making about land management practices.
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Landslide movement in southwest Colorado triggered by atmospheric tides
Schulz, W.H.; Kean, J.W.; Wang, G.
2009-01-01
Landslides are among the most hazardous of geological processes, causing thousands of casualties and damage on the order of billions of dollars annually. The movement of most landslides occurs along a discrete shear surface, and is triggered by a reduction in the frictional strength of the surface. Infiltration of water into the landslide from rainfall and snowmelt and ground motion from earthquakes are generally implicated in lowering the frictional strength of this surface. However, solid-Earth and ocean tides have recently been shown to trigger shear sliding in other processes, such as earthquakes and glacial motion. Here we use observations and numerical modelling to show that a similar processatmospheric tidescan trigger movement in an ongoing landslide. The Slumgullion landslide, located in the SanJuan Mountains of Colorado, shows daily movement, primarily during diurnal low tides of the atmosphere. According to our model, the tidal changes in air pressure cause air and water in the sediment pores to flow vertically, altering the frictional stress of the shear surface; upward fluid flow during periods of atmospheric low pressure is most conducive to sliding. We suggest that tidally modulated changes in shear strength may also affect the stability of other landslides, and that the rapid pressure variations associated with some fast-moving storm systems could trigger a similar response. ?? 2009 Macmillan Publishers Limited. All rights reserved.
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The use of remote sensing for landslide studies in Europe
Tofani, Veronica; Agostini, Andrea; Segoni, Samuele; Catani, Filippo; Casagli, Nicola
2013-04-01
The existing remote sensing techniques and their actual application in Europe for landslide detection, mapping and monitoring have been investigated. Data and information necessary to evaluate the subjects have been collected through a questionnaire, designed using a Google form, which was disseminated among end-users and researchers involved in landslide. In total, 49 answers were collected, coming from 17 European countries and from different kinds of institutions (universities, research institutes, public institutes and private companies). The spatial distribution of the answers is consistent with the distribution of landslides in Europe, the significance of landslides impact on society and the estimated landslide susceptibility in the various countries. The outcomes showed that landslide detection and mapping is mainly performed with aerial photos, often associated with optical and radar imagery. Concerning landslide monitoring, satellite radars prevail over the other types of data followed by aerial photos and meteorological sensors. Since subsampling the answers according to the different typology of institutions it is not noticeable a clear gap between research institutes and end users, it is possible to infer that in landslide remote sensing the research is advancing at the same pace as its day-to-day application. Apart from optical and radar imagery, other techniques are less widespread and some of them are not so well established, notwithstanding their performances are increasing at a fast rate as scientific and technological improvements are accomplished. Remote sensing is mainly used for detection/mapping and monitoring of slides, flows and lateral spreads with a preferably large scale of analysis (1:5000 - 1:25000). All the compilers integrate remote sensing data with other thematic data, mainly geological maps, landslide inventory maps and DTMs and derived maps. Concerning landslide monitoring, the results of the questionnaire stressed that the best
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A GIS-based extended fuzzy multi-criteria evaluation for landslide susceptibility mapping.
Feizizadeh, Bakhtiar; Shadman Roodposhti, Majid; Jankowski, Piotr; Blaschke, Thomas
2014-12-01
Landslide susceptibility mapping (LSM) is making increasing use of GIS-based spatial analysis in combination with multi-criteria evaluation (MCE) methods. We have developed a new multi-criteria decision analysis (MCDA) method for LSM and applied it to the Izeh River basin in south-western Iran. Our method is based on fuzzy membership functions (FMFs) derived from GIS analysis. It makes use of nine causal landslide factors identified by local landslide experts. Fuzzy set theory was first integrated with an analytical hierarchy process (AHP) in order to use pairwise comparisons to compare LSM criteria for ranking purposes. FMFs were then applied in order to determine the criteria weights to be used in the development of a landslide susceptibility map. Finally, a landslide inventory database was used to validate the LSM map by comparing it with known landslides within the study area. Results indicated that the integration of fuzzy set theory with AHP produced significantly improved accuracies and a high level of reliability in the resulting landslide susceptibility map. Approximately 53% of known landslides within our study area fell within zones classified as having "very high susceptibility", with the further 31% falling into zones classified as having "high susceptibility".
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HAZARD ASSESSMENT OF LANDSLIDE DISASTER IN FUJIAN PROVINCE BASED ON FUZZY MATHEMATICS
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J. M. Wang
2018-04-01
Full Text Available Landslide disasters are the most frequent geological disasters in Fujian Province. They are also the type of geological disasters that cause the most serious economic and population losses each year. This study uses the fuzzy mathematics method to carry on the hazard assessment of landslide disaster in Fujian Province, in order to explore the mechanism of the landslide disaster, and provides the reference for the construction land expansion in Fujian Province. The calculation results show that landslide disasters in Fujian Province have a high correlation with external forces, that is, long-term precipitation and short-term strong precipitation are likely to trigger landslide disasters. Among the internal stress factors, the correlation between the occurrence of landslides and slopes is the highest, and the probability of landslides occurs in areas with steep slopes. The evaluation results show that the areas with high landslide hazards are mainly distributed in the central region of Fujian Province. From the remote sensing images, it can be seen that most of the dangerous areas are in rapidly developing cities, and their vegetation coverage is relatively low, and the environment is greatly affected by humans.
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Hazard Assessment of Landslide Disaster in Fujian Province Based on Fuzzy Mathematics
Wang, J. M.; Gong, A. D.; Chen, Y. L.; Li, J.; Zeng, T. T.
2018-04-01
Landslide disasters are the most frequent geological disasters in Fujian Province. They are also the type of geological disasters that cause the most serious economic and population losses each year. This study uses the fuzzy mathematics method to carry on the hazard assessment of landslide disaster in Fujian Province, in order to explore the mechanism of the landslide disaster, and provides the reference for the construction land expansion in Fujian Province. The calculation results show that landslide disasters in Fujian Province have a high correlation with external forces, that is, long-term precipitation and short-term strong precipitation are likely to trigger landslide disasters. Among the internal stress factors, the correlation between the occurrence of landslides and slopes is the highest, and the probability of landslides occurs in areas with steep slopes. The evaluation results show that the areas with high landslide hazards are mainly distributed in the central region of Fujian Province. From the remote sensing images, it can be seen that most of the dangerous areas are in rapidly developing cities, and their vegetation coverage is relatively low, and the environment is greatly affected by humans.
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Filling, storing and draining. Three key aspects of landslide hydrology
Bogaard, Thom; Greco, Roberto
2016-04-01
Rainfall-triggered landslides are among the most widespread hazards in the world. The hydrology in and around a landslide area is key to pore pressure build-up in the soil skeleton which reduces shear strength due to the buoyancy force exerted by water in a saturated soil and to soil suction in an unsaturated soil. Extraordinary precipitation events trigger most of the landslides, but, at the same time, the vast majority of slopes do not fail. The intriguing question is: 'When and where exactly can a slope become triggered to slide and flow downwards?' The objective of this article is to present and discuss landslide hydrology at three scales - pore, hillslope, and catchment - which, taken together, give an overview of this interdisciplinary science. In fact, for rainfall-triggered landslides to occur, an unfavourable hydrological interplay should exist between fast and/or prolonged infiltration, and a relatively 'slow' drainage. The competition of water storage, pressure build-up and the subsequently induced drainage contains the importance of the timing, which is indisputably one of the more delicate but relevant aspects of landslide modelling, the overlay of hydrological processes with different time scales. As slopes generally remain stable, we can argue that effective drainage mechanisms spontaneously develop, as the best for a slope to stay stable is getting rid of the overload of water (above field capacity), either vertically or laterally. So, landslide hydrology could be framed as 'Filling-Storing-Draining'. Obviously, 'Storing' is added to stress the importance of dynamic pressure build-up for slope stability. 'Draining' includes all removal of water from the system (vertical and lateral flow, evaporation and transpiration) and thus pore water pressure release. Furthermore, by addressing landslide hydrology from both earth sciences and soil mechanics perspectives, we aim to manifest the hydrological processes in hillslopes and their influence on behaviour
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Directory of Open Access Journals (Sweden)
Christos Chalkias
2014-04-01
Full Text Available The main aim of this paper is landslide susceptibility assessment using fuzzy expert-based modeling. Factors that influence landslide occurrence, such as elevation, slope, aspect, lithology, land cover, precipitation and seismicity were considered. Expert-based fuzzy weighting (EFW approach was used to combine these factors for landslide susceptibility mapping (Peloponnese, Greece. This method produced a landslide susceptibility map of the investigated area. The landslides under investigation have more or less same characteristics: lateral based and downslope shallow movement of soils or rocks. The validation of the model reveals, that predicted susceptibility levels are found to be in good agreement with the past landslide occurrences. Hence, the obtained landslide susceptibility map could be acceptable, for landslide hazard prevention and mitigation at regional scale.
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A method to add richness to the National Landslide Database of Great Britain
Taylor, Faith; Freeborough, Katy; Malamud, Bruce; Demeritt, David
2014-05-01
Landslides in Great Britain (GB) pose a risk to infrastructure, property and livelihoods. Our understanding of where landslide hazard and impact will be greatest is based on our knowledge of past events. Here, we present a method to supplement existing records of landslides in GB by searching electronic archives of local and regional newspapers. In Great Britain, the British Geological Survey (BGS) are responsible for updating and maintaining records of GB landslide events and their impacts in the National Landslide Database (NLD). The NLD contains records of approximately 16,500 landslide events in Great Britain. Data sources for the NLD include field surveys, academic articles, grey literature, news, public reports and, since 2012, social media. Here we aim to supplement the richness of the NLD by (i) identifying additional landslide events and (ii) adding more detail to existing database entries. This is done by systematically searching the LexisNexis digital archive of 568 local and regional newspapers published in the UK. The first step in the methodology was to construct Boolean search criteria that optimised the balance between minimising the number of irrelevant articles (e.g. "a landslide victory") and maximising those referring to landslide events. This keyword search was then applied to the LexisNexis archive of newspapers for all articles published between 1 January and 31 December 2012, resulting in 1,668 articles. These articles were assessed to determine whether they related to a landslide event. Of the 1,668 articles, approximately 30% (~700) referred to landslide events, with others referring to landslides more generally or themes unrelated to landslides. Examples of information obtained from newspaper articles included: date/time of landslide occurrence, spatial location, size, impact, landslide type and triggering mechanism, although the amount of detail and precision attainable from individual articles was variable. Of the 700 articles found for
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A precipitation-induced landslide susceptibility model for natural gas transmission pipelines
Energy Technology Data Exchange (ETDEWEB)
Finley, Jason P. [Fugro William Lettis and Associates, Inc., Valencia, California (United States); Slayter, David L.; Hitchcock, Chris S. [Fugro William Lettis and Associates, Inc., Walnut Creek, California (United States); Lee, Chih-Hung [Pacific Gas and Electric Company, Gas Systems Integrity Management, Walnut Creek, California (United States)
2010-07-01
Landslides related to heavy rainfall can cause extensive damage to natural gas transmission pipelines. Fugro William Lettis and Associates Inc. have developed and implemented a geographic information system (GIS) model that evaluates near real-time precipitation-induced landslide susceptibility. The model incorporates state-wide precipitation data and geologically-based landslide classifications to produce rapid landslide risk evaluation for Pacific Gas and Electric Company's (PGandE) gas transmission system during winter rain storms in California. The precipitation data include pre-storm event quantitative precipitation forecasts (QPF) and post-storm event quantitative precipitation estimate (QPE) from the United States National Oceanic and Atmospheric Administration (NOAA). The geologic classifications are based on slope, susceptible geologic formations, and the locations of historic or known landslide occurrences. Currently the model is calibrated using qualitative measures. This paper describes the development of the model algorithm and input data, model results, calibration efforts, and the on-going research and landslide collection warranted for continued refinement of the model.
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Huang, H. H.; Hsu, Y. J.; Kuo, C. Y.; Chen, C. C.; Kuo, L. W.; Chen, R. F.; Lin, C. R.; Lin, P. P.; Lin, C. W.; Lin, M. L.; Wang, K. L.
2017-12-01
A unique landslide monitoring project integrating multidisciplinary geophysics experiments such as GPS, inclinometer, piezometer, and spontaneous potential log has been established at Lantai, Ilan area to investigating the possible detachment depth range and the physical mechanism of a slowly creeping landslide. In parallel with this, a lately deployed local seismic network also lends an opportunity to employ the passive seismic imaging technique to detect the time-lapse changes of seismic velocity in and around the landslide area. Such technique that retrieves Green's functions by cross-correlation of continuous ambient noise has opened new opportunities to seismologically monitoring the environmental and tectonic events such as ground water variation, magma intrusion under volcanos, and co-seismic medium damage in recent years. Integrating these geophysical observations, we explore the primary controls of derived seismic velocity changes and especially the hydrological response of the landslide to the passage of Megi typhoon in the last September 2016, which could potentially further our understanding of the dynamic system of landslides and in turn help the hazard mitigation.
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Remote landslide mapping using a laser rangefinder binocular and GPS
Directory of Open Access Journals (Sweden)
M. Santangelo
2010-12-01
Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.
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An integrated methodology to develop a standard for landslide early warning systems
Fathani, Teuku Faisal; Karnawati, Dwikorita; Wilopo, Wahyu
2016-01-01
Landslides are one of the most widespread and commonly occurring natural hazards. In regions of high vulnerability, these complex hazards can cause significant negative social and economic impacts. Considering the worldwide susceptibility to landslides, it is necessary to establish a standard for early warning systems specific to landslide disaster risk reduction. This standard would provide guidance in conducting landslide detection, prediction, interpretation, and response...
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On the paleo-magnetospheres of Earth and Mars
Scherf, Manuel; Khodachenko, Maxim; Alexeev, Igor; Belenkaya, Elena; Blokhina, Marina; Johnstone, Colin; Tarduno, John; Lammer, Helmut; Tu, Lin; Guedel, Manuel
2017-04-01
The intrinsic magnetic field of a terrestrial planet is considered to be an important factor for the evolution of terrestrial atmospheres. This is in particular relevant for early stages of the solar system, in which the solar wind as well as the EUV flux from the young Sun were significantly stronger than at present-day. We therefore will present simulations of the paleo-magnetospheres of ancient Earth and Mars, which were performed for ˜4.1 billion years ago, i.e. the Earth's late Hadean eon and Mars' early Noachian. These simulations were performed with specifically adapted versions of the Paraboloid Magnetospheric Model (PMM) of the Skobeltsyn Institute of Nuclear Physics of the Moscow State University, which serves as ISO-standard for the Earth's magnetic field (see e.g. Alexeev et al., 2003). One of the input parameters into our model is the ancient solar wind pressure. This is derived from a newly developed solar/stellar wind evolution model, which is strongly dependent on the initial rotation rate of the early Sun (Johnstone et al., 2015). Another input parameter is the ancient magnetic dipole field. In case of Earth this is derived from measurements of the paleomagnetic field strength by Tarduno et al., 2015. These data from zircons are varying between 0.12 and 1.0 of today's magnetic field strength. For Mars the ancient magnetic field is derived from the remanent magnetization in the Martian crust as measured by the Mars Global Surveyor MAG/ER experiment. These data together with dynamo theory are indicating an ancient Martian dipole field strength in the range of 0.1 to 1.0 of the present-day terrestrial dipole field. For the Earth our simulations show that the paleo-magnetosphere during the late Hadean eon was significantly smaller than today, with a standoff-distance rs ranging from ˜3.4 to 8 Re, depending on the input parameters. These results also have implications for the early terrestrial atmosphere. Due to the significantly higher EUV flux, the
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Kinematic analysis for the implementation of landslide mitigation measures
Delmonaco, Giuseppe; Margottini, Claudio; Spizzichino, Daniele
2010-05-01
The present work is finalised at the implementation of a landslide risk mitigation master plan of the ancient citadel of Machu Picchu. After the warning launched in March 2001, by the scientific community on potential collapse of the citadel from a near-disastrous landslide event different studies have been promoted to reconstruct landslide activity and suggest landslide risk mitigation measures for the protection and conservation of Machu Picchu cultural heritage. A site-scale analysis has been implemented following the application and integration of geomechanical classifications, ambient noise measurements and structural and kinematical analysis. The geology of the area is characterized by granitoid bodies that had been emplaced in the axial zones of the main rift system that are now exposed at the highest altitudes, together with country rocks (Precambrian and Lower Paleozoic metamorphics) originally constituting the rift ‘roots'. The bedrock of the Inca citadel of Machu Picchu is mainly composed by granite and subordinately granodiorite. This is mainly located in the lower part of the slopes. Superficially, the granite is jointed in blocks with variable dimensions, promoted by local structural setting. Single blocks vary from 10-1 to about 200 m3. Soil cover, widely outcropping in the area, is mainly composed by individual blocks and subordinately by coarse materials originated by chemical and physical weathering of minerals. Regional tectonic uplift and structural setting rule the general morphological features of the area and as a consequence, landslide type and evolution. Rock falls, rock slides, debris flows and debris slides are the main landslide typologies affecting the citadel slopes. In the last mission in May 2009, elastic and deformation rock parameters have been collected using a passive seismic innovative technique based on natural microtremor measurements and geostructural scan lines elaboration. A landslide zoning of the citadel has been
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Landsliding and flooding event triggered by heavy rains in the Rize region
Yalcin, Ali; Kavurmaci, M. Murat
2013-04-01
Rize province has been significantly damaged by frequent landslides and floods which are caused by severe rainfalls and result in many casualties. The area is prone to landslides because of the climate conditions, geologic, and land cover characteristics of the region. The most recent landslide occurred on August 26, 2010 in Gundogdu town. The landslides have caused large numbers of casualties and huge economic losses in the region. Thirteen people died, twenty houses collapsed, more than a hundred houses damaged, and one hundred fifty vehicles were damaged in the Gundogdu landslide. Flood event is often seen in the region of Rize, due to continuous rainfall. Floods cause huge loss of life and property in this region. Rainfall is the most frequent landslide-triggering factor in East Black Sea region, Turkey, especially Rize region. Rize is the rainiest city of Turkey. Total annual precipitation is over 2300 mm, and precipitation is equally distributed in each month. However, in August 26, 166.5 mm precipitation rained within 24 hours in the region and this rainstorm caused great damage. The intensity rainfall periods were become as an indicator of landslide activity. It is very important that the presence of suitable lithologic units for occurring landslides. There are appropriate materials to contributed constitution of landslides in the study area; completely weathered dacite. In addition, intensity land cover types as tea plantations have been blocked surface flows and rainfall is able to quickly penetrate into the soil through open tension cracks that appear in the landslide head and in stretching zones. According to the results of the analysis, the study area has been overlaid tea garden 70 % percentage approximately. Furthermore, the landslide risks have increased by devastation of land cover in this region. In this region, over-steepened slopes, slope saturation in areas of heavy rainfall, and removal of slope vegetation can also increase landslide potential
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ANFIS modeling for the assessment of landslide susceptibility for the Cameron Highland (Malaysia)
Pradhan, Biswajeet; Sezer, Ebru; Gokceoglu, Candan; Buchroithner, Manfred F.
2010-05-01
Landslides are one of the recurrent natural hazard problems throughout most of Malaysia. In landslide literature, there are several approaches such as probabilistic, bivariate and multivariate statistical models, fuzzy and artificial neural network models etc. However, a neuro-fuzzy application on the landslide susceptibility assessment has not been encountered in the literature. For this reason, this study presents the results of an adaptive neuro-fuzzy inference system (ANFIS) using remote sensing data and GIS for landslide susceptibility analysis in a part of the Cameron Highland areas in Malaysia. Landslide locations in the study area were identified by interpreting aerial photographs and satellite images, supported by extensive field surveys. Landsat TM satellite imagery was used to map vegetation index. Maps of topography, lineaments, NDVI and land cover were constructed from the spatial datasets. Seven landslide conditioning factors such as altitude, slope angle, curvature, distance from drainage, lithology, distance from faults and NDVI were extracted from the spatial database. These factors were analyzed using an ANFIS to produce the landslide susceptibility maps. During the model development works, total 5 landslide susceptibility models were constructed. For verification, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the ROC curves for all landslide susceptibility models were drawn and the area under curve values were calculated. Landslide locations were used to validate results of the landslide susceptibility map and the verification results showed 97% accuracy for the model 5 employing all parameters produced in the present study as the landslide conditioning factors. The validation results showed sufficient agreement between the obtained susceptibility map and the existing data on landslide areas. Qualitatively, the model yields reasonable results which can be used for preliminary land
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Preliminary Map of Landslide Deposits in the Mesa Verde National Park Area, Colorado
Carrara, Paul E.
2009-01-01
This report presents a preliminary map of landslide deposits in the Mesa Verde National Park area (see map sheet) at a compilation scale of 1:50,000. Landslide is a general term for landforms produced by a wide variety of gravity-driven mass movements, including various types of flows, slides, topples and falls, and combinations thereof produced by the slow to rapid downslope transport of surficial materials or bedrock. The map depicts more than 200 landslides ranging in size from small (0.01 square miles) earthflows and rock slumps to large (greater than 0.50 square miles) translational slides and complex landslides (Varnes, 1978). This map has been prepared to provide a regional overview of the distribution of landslide deposits in the Mesa Verde area, and as such constitutes an inventory of landslides in the area. The map is suitable for regional planning to identify broad areas where landslide deposits and processes are concentrated. It should not be used as a substitute for detailed site investigations. Specific areas thought to be subject to landslide hazards should be carefully studied before development. Many of the landslides depicted on this map are probably stable as they date to the Pleistocene (approximately 1.8-0.011 Ma) and hence formed under a different climate regime. However, the recognition of these landslides is important because natural and human-induced factors can alter stability. Reduction of lateral support (by excavations or roadcuts), removal of vegetation (by fire or development), or an increase in pore pressure (by heavy rains) may result in the reactivation of landslides or parts of landslides.
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Landslides in West Coast Metropolitan Areas: The Role of Extreme Weather Events
Biasutti, Michela; Seager, Richard; Kirschbaum, Dalia B.
2016-01-01
Rainfall-induced landslides represent a pervasive issue in areas where extreme rainfall intersects complex terrain. A farsighted management of landslide risk requires assessing how landslide hazard will change in coming decades and thus requires, inter alia, that we understand what rainfall events are most likely to trigger landslides and how global warming will affect the frequency of such weather events. We take advantage of 9 years of landslide occurrence data compiled by collating Google news reports and of a high-resolution satellite-based daily rainfall data to investigate what weather triggers landslide along the West Coast US. We show that, while this landslide compilation cannot provide consistent and widespread monitoring everywhere, it captures enough of the events in the major urban areas that it can be used to identify the relevant relationships between landslides and rainfall events in Puget Sound, the Bay Area, and greater Los Angeles. In all these regions, days that recorded landslides have rainfall distributions that are skewed away from dry and low-rainfall accumulations and towards heavy intensities. However, large daily accumulation is the main driver of enhanced hazard of landslides only in Puget Sound. There, landslide are often clustered in space and time and major events are primarily driven by synoptic scale variability, namely "atmospheric rivers" of high humidity air hitting anywhere along the West Coast, and the interaction of frontal system with the coastal orography. The relationship between landslide occurrences and daily rainfall is less robust in California, where antecedent precipitation (in the case of the Bay area) and the peak intensity of localized downpours at sub-daily time scales (in the case of Los Angeles) are key factors not captured by the same-day accumulations. Accordingly, we suggest that the assessment of future changes in landslide hazard for the entire the West Coast requires consideration of future changes in the
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Implications of climate change on landslide hazard in Central Italy.
Alvioli, Massimiliano; Melillo, Massimo; Guzzetti, Fausto; Rossi, Mauro; Palazzi, Elisa; von Hardenberg, Jost; Brunetti, Maria Teresa; Peruccacci, Silvia
2018-07-15
The relation between climate change and its potential effects on the stability of slopes remains an open issue. For rainfall induced landslides, the point consists in determining the effects of the projected changes in the duration and amounts of rainfall that can initiate slope failures. We investigated the relationship between fine-scale climate projections obtained by downscaling and the expected modifications in landslide occurrence in Central Italy. We used rainfall measurements taken by 56 rain gauges in the 9-year period 2003-2011, and the RainFARM technique to generate downscaled synthetic rainfall fields from regional climate model projections for the 14-year calibration period 2002-2015, and for the 40-year projection period 2010-2049. Using a specific algorithm, we extracted a number of rainfall events, i.e. rainfall periods separated by dry periods of no or negligible amount of rain, from the measured and the synthetic rainfall series. Then, we used the selected rainfall events to forcethe Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model TRIGRS v. 2.1. We analyzed the results in terms of variations (or lack of variations) in the rainfall thresholds for the possible initiation of landslides, in the probability distribution of landslide size (area), and in landslide hazard. Results showed that the downscaled rainfall fields obtained by RainFARM can be used to single out rainfall events, and to force the slope stability model. Results further showed that while the rainfall thresholds for landslide occurrence are expected to change in future scenarios, the probability distribution of landslide areas are not. We infer that landslide hazard in the study area is expected to change in response to the projected variations in the rainfall conditions. We expect our results to contribute to regional investigations of the expected impact of projected climate variations on slope stability conditions and on landslide hazards. Copyright
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Dévoli, G.; Strauch, W.; Álvarez, A.; Muñoz, A.; Kjekstad, O.
2009-04-01
A successful landslide hazard and risk assessment requires awareness and good understanding of the potential landslide problems within the geographic area involved. However, this requirement is not always met in developing countries where population, scientific community, and the government may not be aware of the landslide threat. The landslide hazard assessment is often neglected or is based on sparse and not well documented technical information. In Nicaragua (Central America), the basic conditions for landslide hazard and risk assessment were first created after the catastrophic landslides triggered by Hurricane Mitch in October 1998. A single landslide took the life of thousands of people at Casita volcano forcing entire communities to be evacuated or relocated and, furthermore, thousands of smaller landslides caused loss of fertile soils and pasture lands, and made serious damages to the infrastructure. Since those events occurred, the public awareness has increased and the country relies now on new local and national governmental laws and policies, on a number of landslide investigations, and on educational and training programs. Dozens of geologists have been capacitated to investigate landslide prone areas, The Instituto Nicaragüense de Estudios Territoriales (INETER), governmental geo-scientific institution, has assumed the responsibility to help land-use planners and public officials to reduce geological hazard losses. They are committed to work cooperatively with national, international, and local agencies, universities and the private sector to provide scientific information and improve public safety through forecasting and warnings. However, in order to provide successful long-term landslide hazard assessment, the institutions must face challenges related to the scarcity and varied quality of available landslide information; collection and access to dispersed data and documents; organization of landslide information in a form that can be easy to
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Hydrodynamic modeling of tsunamis from the Currituck landslide
Geist, E.L.; Lynett, P.J.; Chaytor, J.D.
2009-01-01
Tsunami generation from the Currituck landslide offshore North Carolina and propagation of waves toward the U.S. coastline are modeled based on recent geotechnical analysis of slide movement. A long and intermediate wave modeling package (COULWAVE) based on the non-linear Boussinesq equations are used to simulate the tsunami. This model includes procedures to incorporate bottom friction, wave breaking, and overland flow during runup. Potential tsunamis generated from the Currituck landslide are analyzed using four approaches: (1) tsunami wave history is calculated from several different scenarios indicated by geotechnical stability and mobility analyses; (2) a sensitivity analysis is conducted to determine the effects of both landslide failure duration during generation and bottom friction along the continental shelf during propagation; (3) wave history is calculated over a regional area to determine the propagation of energy oblique to the slide axis; and (4) a high-resolution 1D model is developed to accurately model wave breaking and the combined influence of nonlinearity and dispersion during nearshore propagation and runup. The primary source parameter that affects tsunami severity for this case study is landslide volume, with failure duration having a secondary influence. Bottom friction during propagation across the continental shelf has a strong influence on the attenuation of the tsunami during propagation. The high-resolution 1D model also indicates that the tsunami undergoes nonlinear fission prior to wave breaking, generating independent, short-period waves. Wave breaking occurs approximately 40-50??km offshore where a tsunami bore is formed that persists during runup. These analyses illustrate the complex nature of landslide tsunamis, necessitating the use of detailed landslide stability/mobility models and higher-order hydrodynamic models to determine their hazard.
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Legorreta Paulin, G.; Bursik, M. I.; Contreras, T.; Polenz, M.; Ramírez Herrera, M.; Paredes Mejía, L.; Arana Salinas, L.
2012-12-01
This poster provides an overview of the on-going research project (Grant SEP-CONACYT no 167495) from the Institute of Geography at the National Autonomous University of Mexico (UNAM) that seeks to conduct a multi-temporal landslide inventory, produce a landslide susceptibility map, and estimate sediment production by using Geographic Information Systems (GIS). The Río El Estado watershed on the southwestern flank of Pico de Orizaba volcano, the highest mountain in Mexico, is selected as a study area. The catchment covers 5.2 km2 with elevations ranging from 2676.79 to 4248.2 m a.s.l. and hillslopes between 0° and 56°. The stream system of Río El Estado catchment erodes Tertiary and Quaternary lavas, pyroclastic flows, and fall deposits. The geologic and geomorphologic factors in combination with high seasonal precipitation, high degree of weathering, and steep slopes predispose the study area to landslides. The methodology encompasses three main stages of analysis to assess landslide hazards: Stage 1 builds a historic landslide inventory. In the study area, an inventory of more than 170 landslides is created from multi-temporal aerial-photo-interpretation and local field surveys to assess landslide distribution. All landslides were digitized into a geographic information system (GIS), and a spatial geo-database of landslides was constructed from standardized GIS datasets. Stage 2 Calculates the susceptibility for the watershed. During this stage, Multiple Logistic Regression and SINMAP) will be evaluated to select the one that provides scientific accuracy, technical accessibility, and applicability. Stage 3 Estimate the potential total material delivered to the main stream drainage channel by all landslides in the catchment. Detailed geometric measurements of individual landslides visited during the field work will be carried out to obtain the landslide area and volume. These measurements revealed an empirical relationship between area and volume that took the
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Landslides in Colorado, USA--Impacts and loss estimation for 2010
Highland, Lynn M.
2012-01-01
The focus of this study is to investigate landslides and consequent losses which affected Colorado in the year 2010. By obtaining landslide reports from a variety of sources, this report will demonstrate the feasibility of creating a profile of landslides and their effects on communities. A short overview of the current status of landslide-loss studies for the United States is introduced, followed by a compilation of landslide occurrence and associated losses and impacts which affected Colorado for the year 2010. Direct costs are summarized in descriptive and tabular form, and where possible, indirect costs are also noted or estimated. Total direct costs of landslides in Colorado for the year 2010 were approximately $9,149,335.00 (2010 U.S. dollars). (Since not all data for damages and costs were obtained, this figure realistically could be considerably higher.) Indirect costs were noted where available but are not totaled due to the fact that most indirect costs were not obtainable for various reasons outlined later in this report. Casualty data are considered as being within the scope of loss evaluation, and are reported in Appendix 1, but are not assigned dollar losses. More details on the source material for loss data not found in the reference section are reported in Appendix 2, and Appendix 3 summarizes notes on landslide-loss investigations in general and lessons learned during the process of loss-data collection.
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Satellite-Based Assessment of Rainfall-Triggered Landslide Hazard for Situational Awareness
Kirschbaum, Dalia; Stanley, Thomas
2018-03-01
Determining the time, location, and severity of natural disaster impacts is fundamental to formulating mitigation strategies, appropriate and timely responses, and robust recovery plans. A Landslide Hazard Assessment for Situational Awareness (LHASA) model was developed to indicate potential landslide activity in near real-time. LHASA combines satellite-based precipitation estimates with a landslide susceptibility map derived from information on slope, geology, road networks, fault zones, and forest loss. Precipitation data from the Global Precipitation Measurement (GPM) mission are used to identify rainfall conditions from the past 7 days. When rainfall is considered to be extreme and susceptibility values are moderate to very high, a "nowcast" is issued to indicate the times and places where landslides are more probable. When LHASA nowcasts were evaluated with a Global Landslide Catalog, the probability of detection (POD) ranged from 8% to 60%, depending on the evaluation period, precipitation product used, and the size of the spatial and temporal window considered around each landslide point. Applications of the LHASA system are also discussed, including how LHASA is used to estimate long-term trends in potential landslide activity at a nearly global scale and how it can be used as a tool to support disaster risk assessment. LHASA is intended to provide situational awareness of landslide hazards in near real-time, providing a flexible, open-source framework that can be adapted to other spatial and temporal scales based on data availability.
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Tsunami Generation and Propagation by 3D deformable Landslides and Application to Scenarios
McFall, Brian C.; Fritz, Hermann M.
2014-05-01
Tsunamis generated by landslides and volcano flank collapse account for some of the most catastrophic natural disasters recorded and can be particularly devastative in the near field region due to locally high wave amplitudes and runup. The events of 1958 Lituya Bay, 1963 Vajont reservoir, 1980 Spirit Lake, 2002 Stromboli and 2010 Haiti demonstrate the danger of tsunamis generated by landslides or volcano flank collapses. Unfortunately critical field data from these events is lacking. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by means of four pneumatic pistons down a 2H:1V slope. The landslide is launched from the sliding box and continues to accelerate by gravitational forces up to velocities of 5 m/s. The landslide Froude number at impact with the water is in the range 1
landslides to study the granulometry effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified -
Criteria for the optimal selection of remote sensing optical images to map event landslides
Fiorucci, Federica; Giordan, Daniele; Santangelo, Michele; Dutto, Furio; Rossi, Mauro; Guzzetti, Fausto
2018-01-01
Landslides leave discernible signs on the land surface, most of which can be captured in remote sensing images. Trained geomorphologists analyse remote sensing images and map landslides through heuristic interpretation of photographic and morphological characteristics. Despite a wide use of remote sensing images for landslide mapping, no attempt to evaluate how the image characteristics influence landslide identification and mapping exists. This paper presents an experiment to determine the effects of optical image characteristics, such as spatial resolution, spectral content and image type (monoscopic or stereoscopic), on landslide mapping. We considered eight maps of the same landslide in central Italy: (i) six maps obtained through expert heuristic visual interpretation of remote sensing images, (ii) one map through a reconnaissance field survey, and (iii) one map obtained through a real-time kinematic (RTK) differential global positioning system (dGPS) survey, which served as a benchmark. The eight maps were compared pairwise and to a benchmark. The mismatch between each map pair was quantified by the error index, E. Results show that the map closest to the benchmark delineation of the landslide was obtained using the higher resolution image, where the landslide signature was primarily photographical (in the landslide source and transport area). Conversely, where the landslide signature was mainly morphological (in the landslide deposit) the best mapping result was obtained using the stereoscopic images. Albeit conducted on a single landslide, the experiment results are general, and provide useful information to decide on the optimal imagery for the production of event, seasonal and multi-temporal landslide inventory maps.
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Directory of Open Access Journals (Sweden)
Pascal Lacroix
2013-05-01
Full Text Available Earthquake is one of the dominant triggering factors of landslides. Given the wide areas covered by mega earthquake-triggered landslides, their inventory requires development of automatic or semi-automatic methods applied to satellite imagery. A detection method is here proposed for this purpose, to fit with simple datasets; SPOT5 panchromatic images of 5 m resolution coupled with a freely and globally available DEM. The method takes advantage of multi-temporal images to detect changes based on radiometric variations after precise coregistration/orthorectification. Removal of false alarms is then undertaken using shape, orientation and radiometric properties of connected pixels defining objects. 80% of the landslides and 93% of the landslide area are detected indicating small omission errors but 50% of false alarms remain. They are removed using expert based analysis of the inventory. The method is applied to realize the first comprehensive inventory of landslides triggered by the Pisco earthquake (Peru, 15/08/2007, Mw 8.0 over an area of 27,000 km2. 866 landslides larger than 100 m2 are detected covering a total area of 1.29 km2. The area/number distribution follows a power-law with an exponent of 1.63, showing a very particular regime of triggering in this arid environment compared to other areas in the world. This specific triggering can be explained by the little soil cover in the coastal and forearc regions of Peru. Analysis of this database finally shows a major control of the topography (both orientation and inclination on the repartition of the Pisco-triggered landslides.
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OVERVIEW OF MODERN RESEARCH OF LANDSLIDES ACCORDING TO AERIAL AND SATELLITE IMAGERY
Directory of Open Access Journals (Sweden)
K. M. Lyapishev
2015-01-01
Full Text Available This article is an overview of researches of landslides using remote sensing methods such as aerial photography, satellite images, radar interferometry, and their combination with the use of GIS technology. Modern methods of investigation of landslides are very diverse. The authors propose different approaches to the identification, classification and monitoring of landslides. Data analysis techniques can help in creating more sophisticated approach to the analysis of landslides.
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Landslide Mobility and Hazards: A Geophysical Overview of the Oso Disaster
Iverson, R. M.; George, D. L.; Allstadt, K.; Godt, J.; Reid, M. E.; Vallance, J. W.; Schilling, S. P.; Cannon, C.; Magirl, C. S.; Collins, B. D.; Baum, R. L.; Coe, J. A.; Schulz, W. H.; Bower, J. B.
2014-12-01
Some landslides move slowly or intermittently downslope, whereas others accelerate catastrophically and run out long distances across flat or gently sloping terrain. Seldom does landsliding of one type transition abruptly into the other, however, and seldom are the consequences more severe than at a site near Oso, Washington, where more than 40 fatalities resulted from a high-speed, long-runout landslide on 22 March 2014. Our interpretations of seismic data inversions and eyewitness accounts indicate that the Oso event began gradually, with remobilization of old landslide deposits that were unusually wet due to months of exceptional precipitation. For about 50 s, relatively slow downslope motion of these deposits withdrew support from a bluff above them, and then the bluff collapsed abruptly. This collapse radiated strong broadband seismic energy and rapidly loaded the old landslide material downslope. We infer that this rapid loading of previously dilated landslide debris caused contractive deformation, widespread liquefaction, and runaway acceleration. The resulting debris avalanche flow (DAF) had a volume of 8 ×106 m3and a fahrböschung (H/L ratio) of 0.106, making it exceptionally mobile for a landslide of its size. The leading edge of the Oso DAF may have gained mobility by entraining water as it displaced the adjacent Stillaguamish River and by liquefying wet floodplain sediments as it overran them, and it formed distal deposits that resembled those of many wood-freighted debris flows. The transition from relatively slow landslide motion (which had occurred intermittently for decades at the Oso site) to high-speed motion and long runout appears to have been very sensitive to contingencies. Our simulations of the Oso event using a new numerical model (D-Claw) show that small differences in water-saturated porosity (n) were sufficient to cause divergent landslide behaviors. In a case with n = 0.38, D-Claw predicts runaway liquefaction and high-speed runout
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Kovács, Gábor; Raveloson, Andrea; Székely, Balázs; Timár, Gábor
2013-04-01
The northern scarp of the Pinka flat - situated in the western part of the Pannonian Basin - is largely characterized by landslides and gullies. This area is a transition zone between the uplifting Eastern Alps and the subsiding Little Hungarian Plain. The interaction of the juxtaposed units results in neotectonically induced features, such as unstable slopes, gullies and landslides. These mass movements represented economical and social hazard in the 20th century. Earlier studies of this area (eg. Kecskés, 1968; Szilágyi, 1989) concentrated on regional scale, but the real nature of mass movements is still unclear. Therefore our goal was to study the landslides on smaller scales. This contribution presents an individual landslide (in the vicinity of Olad, outskirt of Szombathely) that has been examined in detail, using different geophysical and geomorphological methods. Field surveys and geomorphological measurements have been achieved several times (from 2006) to have a better view on the role of geomorphology in the formation of the landslide. Fixed points were deployed inside the landslide as well as near to it to quantify movements of surface over time. The structure of the slope was studied using shallow boreholes and vertical electrical sounding (VES) measurements. Furthermore Electrical Resistivity Tomography (ERT) was used along several transverse and longitudinal profiles to complement these studies with two dimensional electrical resistivity sections. Results from the last 6 years show that the evolution of the landslide seems to be triggered by the weather conditions of the Alpine foothills and the northern scarp of Pinka flat, though the origin of the landslide is neotectonic. Geophysical results show that the sliding mass is situated on a clayey layer. The main cause of mass movement seems to be the slope-parallel layering of the clayey and sandy sediment, though recent time human influence played an important role as well. This research was financed
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Spear, B.; Haritashya, U. K.; Kargel, J. S.
2017-12-01
Gorkha Nepal has been a hot bed of landslide activity since the 7.8 magnitude earthquake that occurred on April 25th 2015. Even though previous studies have mapped and analyzed the landslides that were directly related to the earthquake, this research maps and analyzes the landslides that occurred during monsoon or after monsoon season in 2015 and 2016. Specifically, our objectives included monitoring post-earthquake landslide evolution and reactivation. We also observed landslides which occurred in the steep side slopes of various small rivers and threatened to block the flow of river. Consequently, we used Landsat, Sentinel, ASTER and images available at Google Earth Engine to locate, map, and analyze these landslides. Our preliminary result indicates 5,270 landslides, however 957 of these landslides occurred significantly after the earthquake. Of the 957 landslides, 508 of them occurred during the monsoon season of 2015 and 48 in the 2016 monsoon season. As well as locating and mapping these landslides, we were able to identify that there were 22 landslides blocking rivers and 24 were reactivated. Our result and landslide density maps clearly identifies zones that are prone to landslides. For example, the steepest areas, such as the Helambu or Langtang region, have a very high concentration of landslides since the earthquake. Furthermore, landslides with the largest area were often nearby each other in very steep regions. This research can be used to determine which areas in the Gorkha Nepal region are safe to use and which areas are high risk.
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Landslide Susceptibility Assessment Using Spatial Multi-Criteria Evaluation Model in Rwanda
Directory of Open Access Journals (Sweden)
Jean Baptiste Nsengiyumva
2018-01-01
Full Text Available Landslides susceptibility assessment has to be conducted to identify prone areas and guide risk management. Landslides in Rwanda are very deadly disasters. The current research aimed to conduct landslide susceptibility assessment by applying Spatial Multi-Criteria Evaluation Model with eight layers of causal factors including: slope, distance to roads, lithology, precipitation, soil texture, soil depth, altitude and land cover. In total, 980 past landslide locations were mapped. The relationship between landslide factors and inventory map was calculated using the Spatial Multi-Criteria Evaluation. The results revealed that susceptibility is spatially distributed countrywide with 42.3% of the region classified from moderate to very high susceptibility, and this is inhabited by 49.3% of the total population. In addition, Provinces with high to very high susceptibility are West, North and South (40.4%, 22.8% and 21.5%, respectively. Subsequently, the Eastern Province becomes the peak under low susceptibility category (87.8% with no very high susceptibility (0%. Based on these findings, the employed model produced accurate and reliable outcome in terms of susceptibility, since 49.5% of past landslides fell within the very high susceptibility category, which confirms the model’s performance. The outcomes of this study will be useful for future initiatives related to landslide risk reduction and management.
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Landslide Susceptibility Assessment Using Spatial Multi-Criteria Evaluation Model in Rwanda
Nsengiyumva, Jean Baptiste; Luo, Geping; Nahayo, Lamek; Huang, Xiaotao; Cai, Peng
2018-01-01
Landslides susceptibility assessment has to be conducted to identify prone areas and guide risk management. Landslides in Rwanda are very deadly disasters. The current research aimed to conduct landslide susceptibility assessment by applying Spatial Multi-Criteria Evaluation Model with eight layers of causal factors including: slope, distance to roads, lithology, precipitation, soil texture, soil depth, altitude and land cover. In total, 980 past landslide locations were mapped. The relationship between landslide factors and inventory map was calculated using the Spatial Multi-Criteria Evaluation. The results revealed that susceptibility is spatially distributed countrywide with 42.3% of the region classified from moderate to very high susceptibility, and this is inhabited by 49.3% of the total population. In addition, Provinces with high to very high susceptibility are West, North and South (40.4%, 22.8% and 21.5%, respectively). Subsequently, the Eastern Province becomes the peak under low susceptibility category (87.8%) with no very high susceptibility (0%). Based on these findings, the employed model produced accurate and reliable outcome in terms of susceptibility, since 49.5% of past landslides fell within the very high susceptibility category, which confirms the model’s performance. The outcomes of this study will be useful for future initiatives related to landslide risk reduction and management. PMID:29385096
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Development of a methodology for detection of trigger-landslide rains
International Nuclear Information System (INIS)
Mayorga Marquez, Ruth
2003-01-01
The natural landscape and the environment on where the human kind is developing itself are getting smaller due to human actions. The development of these human activities is diminishing the vegetation in many areas of our planet causing the development of bare soils, which are so vulnerable to the mass land removing processes. Wherever these processes take place, they affect the regional geomorphology and the social end economic development of the regions. Colombia is a country that due to its geographic, geologic, geomorphologic and climatic characteristics is prone to mass land removing processes, especially landslides. These landslides have a great impact on the shaping of the Colombian landscape and their occurrence is very common. According to studies carried out by Castellanos, 1996, 96% of the landslides that take place in Colombia are caused by meteorological events, such as long rainfall periods and strong rainfalls of short duration. Considering that rainfalls are the phenomena that more often speed up mass movements, it is so important to study the relationship between rainfalls and the landslide occurrence. This can be done by determining rainfall thresholds that speed up landslides and by considering factors such as intensity, duration and frequency of the rainfalls events. Research studies on the determination of relationship between rainfalls and mass movements carried out in many countries around the world assume the existence of two main type of speeding up effects caused by rainfalls. The first one, the accumulative effect of the rainfalls, this is a medium term effect (some days) the second one, the immediately effect of the rainfalls which take place some time before the landslide occurrence. The research carried out shows the critical rainfall method for the determination of rainfall thresholds that speed up landslides. This method is based on the analysis of the accumulated precipitation that has fallen previously to the landslide occurrence
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MULTI-SENSOR NETWORK FOR LANDSLIDES SIMULATION AND HAZARD MONITORING - DESIGN AND DEPLOYMENT
Directory of Open Access Journals (Sweden)
H. Wu
2012-08-01
Full Text Available This paper describes a newly developed multi-sensor network system for landslide and hazard monitoring. Landslide hazard is one of the most destructive natural disasters, which has severely affected human safety, properties and infrastructures. We report the results of designing and deploying the multi-sensor network, based on the simulated landslide model, to monitor typical landslide areas and with a goal to predict landslide hazard and mitigate damages. The integration and deployment of the prototype sensor network were carried out in an experiment area at Tongji University in Shanghai. In order to simulate a real landslide, a contractible landslide body is constructed in the experiment area by 7m*1.5m. Then, some different kind of sensors, such as camera, GPS, crackmeter, accelerometer, laser scanning system, inclinometer, etc., are installed near or in the landslide body. After the sensors are powered, continuous sampling data will be generated. With the help of communication method, such as GPRS, and certain transport devices, such as iMesh and 3G router, all the sensor data will be transported to the server and stored in Oracle. These are the current results of an ongoing project of the center. Further research results will be updated and presented in the near future.
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A GIS-based extended fuzzy multi-criteria evaluation for landslide susceptibility mapping
Feizizadeh, Bakhtiar; Shadman Roodposhti, Majid; Jankowski, Piotr; Blaschke, Thomas
2014-01-01
Landslide susceptibility mapping (LSM) is making increasing use of GIS-based spatial analysis in combination with multi-criteria evaluation (MCE) methods. We have developed a new multi-criteria decision analysis (MCDA) method for LSM and applied it to the Izeh River basin in south-western Iran. Our method is based on fuzzy membership functions (FMFs) derived from GIS analysis. It makes use of nine causal landslide factors identified by local landslide experts. Fuzzy set theory was first integrated with an analytical hierarchy process (AHP) in order to use pairwise comparisons to compare LSM criteria for ranking purposes. FMFs were then applied in order to determine the criteria weights to be used in the development of a landslide susceptibility map. Finally, a landslide inventory database was used to validate the LSM map by comparing it with known landslides within the study area. Results indicated that the integration of fuzzy set theory with AHP produced significantly improved accuracies and a high level of reliability in the resulting landslide susceptibility map. Approximately 53% of known landslides within our study area fell within zones classified as having “very high susceptibility”, with the further 31% falling into zones classified as having “high susceptibility”. PMID:26089577
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Application of remote monitoring technology in landslides in the Luoshan mining area
Energy Technology Data Exchange (ETDEWEB)
Man-chao He; Zhi-gang Tao; Bin Zhang [China University of Mining & Technology, Beijing (China). Research Center of Geotechnical Engineering
2009-09-15
With the scale extending of mining, the landslide disaster in the earth's surface will become more and more serious, and these landslide disasters are being threatened to the sustainable safe mining of the underground mine and the open-pit mine. Based on the theory that sliding force is greater than the shear resistance (resisting force) at the potential slip surface is the necessary and sufficient condition to occur the landslide as the sliding criterion, the principle and method for sliding force remote monitoring is presented, and the functional relationship between the human mechanical quantity and the natural sliding force is derived, hereby, the natural sliding force can be calculated according to the human mechanical quantity. Based on above principle and method, a new system of landslide remote monitoring is designed and 53 systems are installed on the landslide body in the Luoshan mining area, which make up the landslide remote monitoring network. According to the results of field test around 8 months, monitoring curves between sliding force and time are obtained, which can describe and forecast the develop trend of landslide. According to above analysis, the results show that this system has some following advantages: (1) real-time monitoring; (2) remote intelligent transmission; (3) landslides early warning. 11 refs., 8 figs., 1 tab.
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Spatial forecast of landslides in three gorges based on spatial data mining.
Wang, Xianmin; Niu, Ruiqing
2009-01-01
The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc). China-Brazil Earth Resources Satellite (Cbers) images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County) in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods.
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Fukuoka, Hiroshi; Watanabe, Eisuke
2017-04-01
Since Keefer published the paper on earthquake magnitude and affected area, maximum epicentral/fault distance of induced landslide distribution in 1984, showing the envelope of plots, a lot of studies on this topic have been conducted. It has been generally supposed that landslides have been triggered by shallow quakes and more landslides are likely to occur with heavy rainfalls immediately before the quake. In order to confirm this, we have collected 22 case records of earthquake-induced landslide distribution in Japan and examined the effect of hypocenter depth and antecedent precipitation. Earthquake magnitude by JMA (Japan Meteorological Agency) of the cases are from 4.5 to 9.0. Analysis on hycpocenter depth showed the deeper quake cause wider distribution. Antecedent precipitation was evaluated using the Soil Water Index (SWI), which was developed by JMA for issuing landslide alert. We could not find meaningful correlation between SWI and the earthquake-induced landslide distribution. Additionally, we found that smaller minimum size of collected landslides results in wider distribution especially between 1,000 to 100,000 m2.
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Landslide Geohazard Monitoring, Early Warning and Stabilization Control Methods
Bednarczyk, Zbigniew
2014-03-01
This paper is a presentation of landslide monitoring, early warning and remediation methods recommended for the Polish Carpathians. Instrumentation included standard and automatic on-line measurements with the real-time transfer of data to an Internet web server. The research was funded through EU Innovative Economy Programme and also by the SOPO Landslide Counteraction Project. The landslides investigated were characterized by relatively low rates of the displacements. These ranged from a few millimetres to several centimetres per year. Colluviums of clayey flysch deposits were of a soil-rock type with a very high plasticity and moisture content. The instrumentation consisted of 23 standard inclinometers set to depths of 5-21 m. The starting point of monitoring measurements was in January 2006. These were performed every 1-2 months over the period of 8 years. The measurements taken detected displacements from several millimetres to 40 cm set at a depth of 1-17 m. The modern, on-line monitoring and early warning system was installed in May 2010. The system is the first of its kind in Poland and only one of several such real-time systems in the world. The installation was working with the Local Road Authority in Gorlice. It contained three automatic field stations for investigation of landslide parameters to depths of 12-16 m and weather station. In-place tilt transducers and innovative 3D continuous inclinometer systems with sensors located every 0.5 m were used. It has the possibility of measuring a much greater range of movements compared to standard systems. The conventional and real-time data obtained provided a better recognition of the triggering parameters and the control of geohazard stabilizations. The monitoring methods chosen supplemented by numerical modelling could lead to more reliable forecasting of such landslides and could thus provide better control and landslide remediation possibilities also to stabilization works which prevent landslides.
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Apply data mining to analyze the rainfall of landslide
Directory of Open Access Journals (Sweden)
Lee Chou-Yuan
2018-01-01
Full Text Available Taiwan is listed as extremely dangerous country which suffers from many disasters. The disasters from the landslide result in the loss of agricultural productions, life and property and so on. Many researchers concern about the disasters of landslide, but there are few discussions for the threshold of rainfall for landslide. In this paper, data mining is applied to establish rules and the threshold of rainfall for landslide in Huafan University, Taiwan. These used variables include rainfall, insolation, insolation rate, averaged humidity, averaged temperature, wind speed, and the tilt of inclinometer. The inclinometer is an important instrument for measuring tilt, elevation or depression of an object with respect to gravity. There are 26 inclinometers in Talun mountain area of Huafan University. In this research, the used data were collected from January 2008 to July 2014. In the proposed approach, the regression analysis is used to predict rainfall first. Then, decision tree is used to obtain decision rules and set the threshold of rainfall for landslide. The output of this approach can provide more information for understanding the change of rainfall. The threshold of rainfall could also provide useful information to maintain the security for Huafan University.
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Management of a typhoon-induced landslide in Otomura (Japan)
Fujisawa, Kazunori; Marcato, Gianluca; Nomura, Yasuhiro; Pasuto, Alessandro
2010-12-01
Late in January 2004 slope instability evidence such as cracks and subsidence appeared on a retaining wall along National Highway 168, near Otomura (Nara Prefecture, Japan). This road plays a strategic role as a long distance route for passenger vehicles and trucks, therefore detailed investigations and constant surveillance have to be carried out in order to manage the induced risk situations. Six months later, on August 10th, a large landslide occurred due to heavy rainfalls related to typhoons #10 and #11 that hit Japan on the first week of August. Field and aerial surveys of the site were carried out soon after the appearance of the first geomorphologic evidence of landslide movements, and a monitoring system was immediately set up. Landslide displacements have been measured since the early stage of movement and road traffic was strictly controlled in order to minimize possible damage. This paper illustrates the effects of landslide activation and the investigations carried out in order to assess landslide hazard and predict the time of failure. Suitable methods for risk management oriented to increase the public safety and including risk control and crisis mitigation acts are also discussed.
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The Fractal Characteristics of the Landslides by Box-Counting and P-A Model
Wang, Zhiwang; Zhou, Fangfang; Cao, Hao
2018-01-01
The landslide is a kind of complicated phenomenon with nonlinear inter-reaction. The traditional theories and methods are difficult to study the uncertainty characteristics of dynamic evolution of the landslides. This paper applies box-counting and P-A model to study the fractal characteristics of geometric shape and spatial distribution of the landslide hazards in the study area from Badong county to Zigui county in TGP reservoir region. The data obtained from the study area shows power-law distributions of geometric shape and spatial distribution of the landslides, and thus reveals some fractal or self-similarity properties. The fractral dimensions DAP of the spatial distribution of landslides by P-A model shows that DAP of the western landslides in the study area are smaller than those of the east, which shows that the geometry of the eastern landslide is more irregular and complicated than the western ones. The results show box-counting model and P-A model can be used to characterize the fractal characteristics of geometric shape and spatial distribution of the landslides.
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Hyperspectral and thermal methodologies applied to landslide monitoring
Vellico, Michela; Sterzai, Paolo; Pietrapertosa, Carla; Mora, Paolo; Berti, Matteo; Corsini, Alessandro; Ronchetti, Francesco; Giannini, Luciano; Vaselli, Orlando
2010-05-01
Landslide monitoring is a very actual topic. Landslides are a widespread phenomenon over the European territory and these phenomena have been responsible of huge economic losses. The aim of the WISELAND research project (Integrated Airborne and Wireless Sensor Network systems for Landslide Monitoring), funded by the Italian Government, is to test new monitoring techniques capable to rapidly and successfully characterize large landslides in fine soils. Two active earthflows in the Northern Italian Appenines have been chosen as test sites and investigated: Silla (Bologna Province) and Valoria (Modena Province). The project implies the use of remote sensing methodologies, with particular focus on the joint use of airborne Lidar, hyperspectral and thermal systems. These innovative techniques give promising results, since they allow to detect the principal landslide components and to evaluate the spatial distribution of parameters relevant to landslide dynamics such as surface water content and roughness. In this paper we put the attention on the response of the terrain related to the use of a hyperspectral system and its integration with the complementary information obtained using a thermal sensor. The potentiality of a hyperspectral dataset acquired in the VNIR (Visible Near Infrared field) and of the spectral response of the terrain could be high since they give important information both on the soil and on the vegetation status. Several significant indexes can be calculated, such as NDVI, obtained considering a band in the Red field and a band in the Infrared field; it gives information on the vegetation health and indirectly on the water content of soils. This is a key point that bridges hyperspectral and thermal datasets. Thermal infrared data are closely related to soil moisture, one of the most important parameter affecting surface stability in soil slopes. Effective stresses and shear strength in unsaturated soils are directly related to water content, and
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Bacha, Alam Sher; Shafique, Muhammad; van der Werff, H.M.A.
2018-01-01
A comprehensive landslide inventory and susceptibility maps are prerequisite for developing and implementing landslide mitigation strategies. Landslide susceptibility maps for the landslides prone regions in northern Pakistan are rarely available. The Hunza-Nagar valley in northern Pakistan is known
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Coupled DEM-CFD analyses of landslide-induced debris flows
Zhao, Tao
2017-01-01
This book reflects the latest research results in computer modelling of landslide-induced debris flows. The book establishes an understanding of the initiation and propagation mechanisms of landslides by means of numerical simulations, so that mitigation strategies to reduce the long-term losses from landslide hazards can be devised. In this context, the book employs the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) to investigate the mechanical and hydraulic behaviour of granular materials involved in landslides – an approach that yields meaningful insights into the flow mechanisms, concerning e.g. the mobilization of sediments, the generation and dissipation of excess pore water pressures, and the evolution of effective stresses. As such, the book provides valuable information, useful methods and robust numerical tools that can be successfully applied in the field of debris flow research.
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Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River, China
Directory of Open Access Journals (Sweden)
Yueping Yin
2016-10-01
Full Text Available The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir (TGR. After construction of the TGR, the water level was raised from 70 m to 175 m above sea level (ASL, and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008. This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014. The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment. Based on this, the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns, i.e. accumulation landslide, dip-slope landslide, reversed bedding landslide, rockfall, and karst breccia landslide. The accumulation landslides and dip-slope landslides account for more than 90%. Taking the Shuping accumulation landslide (a sliding mass volume of 20.7 × 106 m3 in Zigui County and the Outang dip-slope landslide (a sliding mass volume of about 90 × 106 m3 in Fengjie County as two typical cases, the mechanisms of reactivation of the two landslides are analyzed. The monitoring data and factor of safety (FOS calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL, and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL. The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied, and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region. Simulation results of the Ganjingzi landslide in Wushan County indicate the
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Sudmeier-Rieux, K.; Breguet, A.; Dubois, J.; Jaboyedoff, M.
2009-04-01
Several thousand landslides were triggered by the Kashmir earthquake, scarring the hillside with cracks. Monsoon rains continue to trigger landslides, which have increased the exposure of populations because of lost agricultural lands, blocked roads and annual fatalities due to landslides. The great majority of these landslides are shallow and relatively small but greatly impacting the population. In this region, landslides were a factor before the earthquake, mainly due to road construction and gravel excavation, but the several thousand landslides triggered by the earthquake have completely overwhelmed the local population and authorities. In Eastern Nepal, the last large earthquake to hit this region occurred in 1988, also triggering numerous landslides and cracks. Here, landslides can be considered a more common phenomenon, yet coping capacities amount to local observations of landslide movement, subsequent abandonment of houses and land as they become too dangerous. We present a comparative case study from Kashmir, Pakistan and Eastern Nepal, highlighting an interdisciplinary approach to understanding the complex interactions between land use, landslides and vulnerability. Our approach sets out to understand underlying causes of the massive landslides triggered by the 2005 earthquake in Kashmir, Pakistan, and also the increasing number of landslides in Nepal. By approaching the issue of landslides from multiple angles (risk perceptions, land use, local coping capacities, geological assessment, risk mapping) and multiple research techniques (remote sensing, GIS, geological assessment, participatory mapping, focus groups) we are better able to create a more complete picture of the "hazardscape". We find that by combining participatory social science research with hazard mapping, we obtain a more complete understanding of underlying causes, coping strategies and possible mitigation options, placing natural hazards in the context of everyday life. This method is
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Wartman, J.; Keaton, J. R.; Scott, A.; Benoit, J.; delaChapelle, J.; Gilbert, R.; Montgomery, D. R.
2014-12-01
We report the findings of the NSF-supported Geotechnical Extreme Events Reconnaissance (GEER) investigation of the Oso Landslide. Our findings are principally based on data collected during a four-day team reconnaissance across the entire landslide area, but also draw upon other data sources including lidar surveys, high-resolution imagery, geologic mapping, precipitation data, and seismic records. The Oso Landslide claimed 43 lives, making it the deadliest landslide disaster in U.S. history. The landslide occurred within a thick sequence of glacial sediments that were deposited into the North Fork Stillaguamish River valley during the last glacial advance. Geomorphic evidence suggests that the valley in the vicinity of Oso Landslide has experienced multiple large landslides over at least the past 6,000 years. Intense three-week rainfall that immediately preceded the event very probably played an important role in triggering the landslide; however, many other factors likely contributed to destabilization of the landslide mass. These include: (i) alteration of the local groundwater recharge and hydrogeological regime due to previous landsliding and, possibly, land use practices, (ii) weakening and alteration of the landslide mass due to previous landsliding and other natural geologic processes, and (iii) changes in stress distribution resulting from removal and deposition of material from earlier landsliding. During our field reconnaissance we identified six distinctive landslide zones and several subzones that are characterized by different geomorphic expression resulting from deformation styles, geologic materials, vegetation, and sequence of deposition. Based on the reconnaissance observations and other available data, we hypothesize that the landslide occurred in two major stages. The first stage of movement is interpreted to be a remobilization of the 2006 slide mass and headward extension that included part or all of the forested slope of an ancient landslide
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Evolution of earthquake-triggered landslides in the Kashmir Himalaya, northern Pakistan
Khattak, G.A.; Owen, L.A.; Kamp, U.; Harp, E.L.
2010-01-01
The influence of the 08 October 2005 Kashmir earthquake and subsequent snow melt and monsoon rainfall on slope stability was evaluated using repeat photography in the Kashmir Himalaya of northern Pakistan. Sixty-eight landslide-affected locations were selected and photographed in November 2005, May/June 2006, June 2007, and August 2007 to evaluate all potential geomorphic changes. Eighty percent of the locations showed no or very little change, 11% of the locations showed a partial vegetation recovery on the slopes, while 9% showed an increase in the landslide area. All those locations that showed an increase in landsliding were located along rivers and/or roads. The small change in landslide extent is remarkable given that the region experienced one of the heaviest monsoon seasons in the last decade and is counter to earlier predictions of accelerated slope erosion by landsliding in the immediate years following the earthquake. Extensive fissures and ground cracks at many localities, however, still present a potential of future landsliding under wetter conditions. ?? 2009 Elsevier B.V. All rights reserved.
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Plan curvature and landslide probability in regions dominated by earth flows and earth slides
Ohlmacher, G.C.
2007-01-01
Damaging landslides in the Appalachian Plateau and scattered regions within the Midcontinent of North America highlight the need for landslide-hazard mapping and a better understanding of the geomorphic development of landslide terrains. The Plateau and Midcontinent have the necessary ingredients for landslides including sufficient relief, steep slope gradients, Pennsylvanian and Permian cyclothems that weather into fine-grained soils containing considerable clay, and adequate precipitation. One commonly used parameter in landslide-hazard analysis that is in need of further investigation is plan curvature. Plan curvature is the curvature of the hillside in a horizontal plane or the curvature of the contours on a topographic map. Hillsides can be subdivided into regions of concave outward plan curvature called hollows, convex outward plan curvature called noses, and straight contours called planar regions. Statistical analysis of plan-curvature and landslide datasets indicate that hillsides with planar plan curvature have the highest probability for landslides in regions dominated by earth flows and earth slides in clayey soils (CH and CL). The probability of landslides decreases as the hillsides become more concave or convex. Hollows have a slightly higher probability for landslides than noses. In hollows landslide material converges into the narrow region at the base of the slope. The convergence combined with the cohesive nature of fine-grained soils creates a buttressing effect that slows soil movement and increases the stability of the hillside within the hollow. Statistical approaches that attempt to determine landslide hazard need to account for the complex relationship between plan curvature, type of landslide, and landslide susceptibility. ?? 2007 Elsevier B.V. All rights reserved.
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Landslide Susceptibility Assessment in the Central Part of Republic of Moldova
Ercanoglu, Murat; Boboc, Nicolae; Sirodoev, Igor; Ahmet Temiz, F.; Sirodoev, Ghenadi
2010-05-01
There has been an increasing interest in natural hazard assessments within the scientific community, particularly in the last two decades. In other respect, there is also a dramatically rising trend in the number of natural hazards. Growing population and expansion of settlements and lifelines over hazardous areas have largely increased the impact of natural disasters both in industrialized and developing countries. Furthermore, natural disasters such as earthquakes, landslides, floods have dramatic effects on human life, infrastructures, environment, and so on. Landslides, one of the most destructive natural hazards, constitute a major geological hazard throughout the world, like in Turkey and Moldova. There are a lot of regions affected by landslides in Turkey (particularly the West, Middle and East Black Sea Region) and Moldova (e.g.: area between Nisporeni, Calarasi, Balti, Western Rezina District, Codri Hills in Central Moldova etc.), and consequences of landslides are of great importance in the two countries. In the last 50 years' period, only the economic loss due to landslides in Turkey is estimated about 5 billion , and 12.5 % of the whole settlement areas, including big and populated cities, are facing landslide threat. Similar to Turkey, there are about 16000 areas affected by landslides in Moldova. In February-March, 1998 the intensity of landslides in the central part of Moldova, including Chisinau, considerably increased. In total, 357 private households involving 1400 people were affected, 214 houses were destroyed, and 137 were damaged. The total national damage accounted for 44.3 million Lei. At present on Moldavian territory, there are more than 17000 landslides of various types. These landslides are mostly located within Central Moldavian heights, one of the most complicated geomorphologic structure and territory's fragmentation. Among major landslide triggering factors, in addition to natural ones, one should also consider the anthropogenic
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The Paleo-Anthropocene and the Genesis of the Current Landscape of Israel
Directory of Open Access Journals (Sweden)
Ackermann Oren
2017-12-01
Full Text Available Worldwide, human impact on natural landscapes has intensified since prehistoric times, and this is well documented in the global archaeological record. The period between the earliest hominids and the Industrial Revolution of the late 18-19th centuries is known as the Paleo-Anthropocene. The current study reviews key geoarchaeological, floral and faunal factors of the Paleo-Anthropocene in Israel, an area that has undergone human activities in various intensities since prehistoric times. It discusses significant human imprints on these three features in the Israeli landscape, demonstrating that its current form is almost entirely anthropogenic. Moreover, some of the past physical changes still dynamically shape Israel’s zoological, archaeological and geomorphic landscape today. It is hoped that insights from this article might aid in guiding present-day management strategies of undeveloped areas through renewal of human activity guided by traditional knowledge.
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Muto, Francesco; Conforti, Massimo; Critelli, Salvatore; Fabbricatore, Davide; Filomena, Luciana; Rago, Valeria; Robustelli, Gaetano; Scarciglia, Fabio; Versace, Pasquale
2014-05-01
The interaction of landslides with linear infrastructures is often the cause of disasters. In Italy landslide impact on roads, railways and buildings cause millions of Euro per year in damage and restoration as well. The proposed study is aimed to the landslide susceptibility evaluation using a multidisciplinary approach: geological and geomorphological survey, statistical analysis and GIS technique, along a section of highway "A3 (Salerno-Reggio Calabria)" between Cosenza Sud and Altilia, northern Calabria. This study is included in a wider research project, named: PON01-01503, Landslides Early Warning-Sistemi integrati per il monitoraggio e la mitigazione del rischio idrogeologico lungo le grandi vie di comunicazione - aimed at the hydrogeological risk mitigation and at the early warning along the highways. The work was first based on air-photo interpretations and field investigations, in order to realize the geological map, geomorphological map and landslide inventory map. In the study area the geomorphology is strongly controlled by its bedrock geology and tectonics. The bedrock geology consists of Neogene sedimentary rocks that cover a thick stack of allochthonous nappes. These nappes consist of crystalline rocks mainly gneiss, phyllite and schist. A total of 835 landslides were mapped and the type of movement are represented mainly by slides and complex and subordinately flow. In order to estimate and validate landslide susceptibility the landslides were divided in two group. One group (training set) was used to prepare susceptibility map and the second group (validation set) to validate the map. Then, the selection of predisposing factors was performed, according with the geological and geomorphological settings of the study area: lithology, distance from tectonic elements, land use, slope, aspect, stream power index (SPI) and plan curvature. In order to evaluate landslide susceptibility Conditional Analysis was applied to Unique Conditions Units (UCUs
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Use of Satellite Remote Sensing Data in the Mapping of Global Landslide Susceptibility
Hong, Yang; Adler, Robert F.; Huffman, George J.
2007-01-01
Satellite remote sensing data has significant potential use in analysis of natural hazards such as landslides. Relying on the recent advances in satellite remote sensing and geographic information system (GIS) techniques, this paper aims to map landslide susceptibility over most of the globe using a GIs-based weighted linear combination method. First , six relevant landslide-controlling factors are derived from geospatial remote sensing data and coded into a GIS system. Next, continuous susceptibility values from low to high are assigned to each of the six factors. Second, a continuous scale of a global landslide susceptibility index is derived using GIS weighted linear combination based on each factor's relative significance to the process of landslide occurrence (e.g., slope is the most important factor, soil types and soil texture are also primary-level parameters, while elevation, land cover types, and drainage density are secondary in importance). Finally, the continuous index map is further classified into six susceptibility categories. Results show the hot spots of landslide-prone regions include the Pacific Rim, the Himalayas and South Asia, Rocky Mountains, Appalachian Mountains, Alps, and parts of the Middle East and Africa. India, China, Nepal, Japan, the USA, and Peru are shown to have landslide-prone areas. This first-cut global landslide susceptibility map forms a starting point to provide a global view of landslide risks and may be used in conjunction with satellite-based precipitation information to potentially detect areas with significant landslide potential due to heavy rainfall. 1
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Multiple Landslide-Hazard Scenarios Modeled for the Oakland-Berkeley Area, Northern California
Pike, Richard J.; Graymer, Russell W.
2008-01-01
With the exception of Los Angeles, perhaps no urban area in the United States is more at risk from landsliding, triggered by either precipitation or earthquake, than the San Francisco Bay region of northern California. By January each year, seasonal winter storms usually bring moisture levels of San Francisco Bay region hillsides to the point of saturation, after which additional heavy rainfall may induce landslides of various types and levels of severity. In addition, movement at any time along one of several active faults in the area may generate an earthquake large enough to trigger landslides. The danger to life and property rises each year as local populations continue to expand and more hillsides are graded for development of residential housing and its supporting infrastructure. The chapters in the text consist of: *Introduction by Russell W. Graymer *Chapter 1 Rainfall Thresholds for Landslide Activity, San Francisco Bay Region, Northern California by Raymond C. Wilson *Chapter 2 Susceptibility to Deep-Seated Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike and Steven Sobieszczyk *Chapter 3 Susceptibility to Shallow Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Kevin M. Schmidt and Steven Sobieszczyk *Chapter 4 Landslide Hazard Modeled for the Cities of Oakland, Piedmont, and Berkeley, Northern California, from a M=7.1 Scenario Earthquake on the Hayward Fault Zone by Scott B. Miles and David K. Keefer *Chapter 5 Synthesis of Landslide-Hazard Scenarios Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike The plates consist of: *Plate 1 Susceptibility to Deep-Seated Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike, Russell W. Graymer, Sebastian Roberts, Naomi B. Kalman, and Steven Sobieszczyk *Plate 2 Susceptibility to Shallow Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Kevin M. Schmidt and Steven
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Geertsema, Marten; Blais-Stevens, Andrée; Kwoll, Eva; Menounos, Brian; Venditti, Jeremy G.; Grenier, Alain; Wiebe, Kelsey
2018-02-01
The Lakelse Lake area in northwestern British Columbia, Canada, has a long history, and prehistory, of rapid sensitive clay landslides moving on very low gradients. However, until now, many landslides have gone undetected. We use an array of modern tools to identify hitherto unknown or poorly known landslide deposits, including acoustic subbottom profiles, multibeam sonar, and LiDAR. The combination of these methods reveals not only landslide deposits, but also geomorphic and sedimentologic structures that give clues about landslide type and mode of emplacement. LiDAR and bathymetric data reveal the areal extent of landslide deposits as well as the orientation of ridges that differentiate between spreading and flowing kinematics. The subbottom profiles show two-dimensional structures of disturbed landslide deposits, including horst and grabens indicative of landslides classified as spreads. A preliminary computer tomography (CT) scan of a sediment core confirms the structures of one subbottom profile. We also use archival data from the Ministry of Transportation and Infrastructure and resident interviews to better characterize historic landslides.
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A systematic review of the health impacts of mass Earth movements (landslides).
Kennedy, Iain T R; Petley, Dave N; Williams, Richard; Murray, Virginia
2015-04-30
Background. Mass ground movements (commonly referred to as 'landslides') are common natural hazards that can have significant economic, social and health impacts. They occur as single events, or as clusters, and are often part of 'disaster' chains, occurring secondary to, or acting as the precursor of other disaster events. Whilst there is a large body of literature on the engineering and geological aspects of landslides, the mortality and morbidity caused by landslides is less well documented. As far as we are aware, this is the first systematic review to examine the health impacts of landslides. Methods. The MEDLINE, EMBASE, CINAHL, SCOPUS databases and the Cochrane library were systematically searched to identify articles which considered the health impacts of landslides. Case studies, case series, primary research and systematic reviews were included. News reports, editorials and non-systematic reviews were excluded. Only articles in English were considered. The references of retrieved papers were searched to identify additional articles. Findings. 913 abstracts were reviewed and 143 full text articles selected for review. A total of 27 papers reporting research studies were included in the review (25 from initial search, 1 from review of references and 1 from personal correspondence). We found a limited number of studies on the physical health consequences of landslides. Only one study provided detail of the causes of mortality and morbidity in relation a landslide event. Landslides cause significant mental health impacts, in particular the prevalence of PTSD may be higher after landslides than other types of disaster, though these studies tend to be older with only 3 papers published in the last 5 years, with 2 being published 20 years ago, and diagnostic criteria have changed since they were produced. Discussion. We were disappointed at the small number of relevant studies, and the generally poor documentation of the health impacts of landslides. Mental
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Landslide hazard zonation around Gilgel Gibe-II Hydroelectric ...
African Journals Online (AJOL)
The present study was carried out along the newly constructed road from Fofa town to Gilgel Gibe-II powerhouse in South western Ethiopia. In this study, an attempt has been made to provide information on the landslide hazard zones present along the new road. In order to delineate the hazardous zones the landslide ...
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Studying Landslide Displacements in Megamendung (Indonesia Using GPS Survey Method
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Hasanuddin Z. Abidin
2004-11-01
Full Text Available Landslide is one of prominent geohazards that frequently affects Indonesia, especially in the rainy season. It destroys not only environment and property, but usually also causes deaths. Landslide monitoring is therefore very crucial and should be continuously done. One of the methods that can have a contribution in studying landslide phenomena is repeated GPS survey method. This paper presents and discusses the operational performances, constraints and results of GPS surveys conducted in a well known landslide prone area in West Java (Indonesia, namely Megamendung, the hilly region close to Bogor. Three GPS surveys involving 8 GPS points have been conducted, namely on April 2002, May 2003 and May 2004, respectively. The estimated landslide displacements in the area are relatively quite large in the level of a few dm to a few m. Displacements up to about 2-3 m were detected in the April 2002 to May 2003 period, and up to about 3-4 dm in the May 2003 to May 2004 period. In both periods, landslides in general show the northwest direction of displacements. Displacements vary both spatially and temporally. This study also suggested that in order to conclude the existence of real and significant displacements of GPS points, the GPS estimated displacements should be subjected to three types of testing namely: the congruency test on spatial displacements, testing on the agreement between the horizontal distance changes with the predicted direction of landslide displacement, and testing on the consistency of displacement directions on two consecutive periods.
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Long term monitoring of landslide: observation gravitational slope cycles
Palis, Edouard; Lebourg, Thomas; Vidal, Maurin
2016-04-01
Since several years of studies on landslides, we realized the role and subtle interactions that existed between the structural complexity, masses dynamics and complex internal circulation of fluids. Thus, to gain a better understanding of the processes taking place during the evolution of an unstable slope, an observational study is necessary. In this perspective, our team currently monitors slow moving landslide zones. The aim of such a monitoring is to gain a better knowledge of the links between external forcing (meteorological, seismological) and signals going out of the slope (kinematic, vibrations, electrical resistivity). In December 2000, a dramatic event affected the sandy/clayey landslide in the Southern Alpes Maritimes (France). A 10 meters high scarp appeared at the foot of the landslide and affected private yards nearby. This area then became a major concern for local authorities and understand the processes taking place, a scientific challenge. In order to understand the land-sliding reactivations and to quantify the natural cycles of deformations, we analyse the main factors of this complex system. After 10 years of observation we are now able to highlight some of the complex behaviours by the measurement of physical parameters (geophysical monitoring). A permanent 115 m ERT line (5 meters electrode spacing) has been installed and provides an acquisition daily since 2006. The daily acquisitions are now accompanied by continuous measurements from boreholes (thermometers, piezometers, tiltmeters) and pluviometry. We are able to control the whole monitoring from the lab, and all these data are transmitted in real time. The analysis of these large amounts of data over large time series allows the detection of seasonal cycles of surface activity. The deformation taking place can be assimilated to a near-elastic deformation and show a lateral decoupling on both sides of the fault cutting the landslide. These deformation cycles can be associated with the
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Object-oriented identification of forested landslides with derivatives of single pulse LiDAR data
Van Den Eeckhaut, Miet; Kerle, Norman; Poesen, Jean; Hervás, Javier
2012-11-01
In contrast to the many studies that use expert-based analysis of LiDAR derivatives for landslide mapping in forested terrain, only few studies have attempted to develop (semi-)automatic methods for extracting landslides from LiDAR derivatives. While all these studies are pixel-based, it has not yet been tested whether object-oriented analysis (OOA) could be an alternative. This study investigates the potential of OOA using only single-pulse LiDAR derivatives, such as slope gradient, roughness and curvature to map landslides. More specifically, the focus is on both LiDAR data segmentation and classification of slow-moving landslides in densely vegetated areas, where spectral data do not allow accurate landslide identification. A multistage procedure has been developed and tested in the Flemish Ardennes (Belgium). The procedure consists of (1) image binarization and multiresolution segmentation, (2) classification of landslide parts (main scarps and landslide body segments) and non-landslide features (i.e. earth banks and cropland fields) with supervised support vector machines at the appropriate scale, (3) delineation of landslide flanks, (4) growing of a landslide body starting from its main scarp, and (5) final cleaning of the inventory map. The results obtained show that OOA using LiDAR derivatives allows recognition and characterization of profound morphologic properties of forested deep-seated landslides on soil-covered hillslopes, because more than 90% of the main scarps and 70% of the landslide bodies of an expert-based inventory were accurately identified with OOA. For mountainous areas with bedrock, on the other hand, creation of a transferable model is expected to be more difficult.
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Allometry indicates giant eyes of giant squid are not exceptional.
Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Gamarra, Ashlee R; Lee, Johanna J; Wainwright, Peter C
2013-02-18
The eyes of giant and colossal squid are among the largest eyes in the history of life. It was recently proposed that sperm whale predation is the main driver of eye size evolution in giant squid, on the basis of an optical model that suggested optimal performance in detecting large luminous visual targets such as whales in the deep sea. However, it is poorly understood how the eye size of giant and colossal squid compares to that of other aquatic organisms when scaling effects are considered. We performed a large-scale comparative study that included 87 squid species and 237 species of acanthomorph fish. While squid have larger eyes than most acanthomorphs, a comparison of relative eye size among squid suggests that giant and colossal squid do not have unusually large eyes. After revising constants used in a previous model we found that large eyes perform equally well in detecting point targets and large luminous targets in the deep sea. The eyes of giant and colossal squid do not appear exceptionally large when allometric effects are considered. It is probable that the giant eyes of giant squid result from a phylogenetically conserved developmental pattern manifested in very large animals. Whatever the cause of large eyes, they appear to have several advantages for vision in the reduced light of the deep mesopelagic zone.
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Wdowinski, S.; Peng, Z.; Ferrier, K.; Lin, C. H.; Hsu, Y. J.; Shyu, J. B. H.
2017-12-01
Earthquakes, landslides, and tropical cyclones are extreme hazards that pose significant threats to human life and property. Some of the couplings between these hazards are well known. For example, sudden, widespread landsliding can be triggered by large earthquakes and by extreme rainfall events like tropical cyclones. Recent studies have also shown that earthquakes can be triggered by erosional unloading over 100-year timescales. In a NASA supported project, titled "Cascading hazards: Understanding triggering relations between wet tropical cyclones, landslides, and earthquake", we study triggering relations between these hazard types. The project focuses on such triggering relations in Taiwan, which is subjected to very wet tropical storms, landslides, and earthquakes. One example for such triggering relations is the 2009 Morakot typhoon, which was the wettest recorded typhoon in Taiwan (2850 mm of rain in 100 hours). The typhoon caused widespread flooding and triggered more than 20,000 landslides, including the devastating Hsiaolin landslide. Six months later, the same area was hit by the 2010 M=6.4 Jiashian earthquake near Kaohsiung city, which added to the infrastructure damage induced by the typhoon and the landslides. Preliminary analysis of temporal relations between main-shock earthquakes and the six wettest typhoons in Taiwan's past 50 years reveals similar temporal relations between M≥5 events and wet typhoons. Future work in the project will include remote sensing analysis of landsliding, seismic and geodetic monitoring of landslides, detection of microseismicity and tremor activities, and mechanical modeling of crustal stress changes due to surface unloading.
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Landslide Change Detection Based on Multi-Temporal Airborne LiDAR-Derived DEMs
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Omar E. Mora
2018-01-01
Full Text Available Remote sensing technologies have seen extraordinary improvements in both spatial resolution and accuracy recently. In particular, airborne laser scanning systems can now provide data for surface modeling with unprecedented resolution and accuracy, which can effectively support the detection of sub-meter surface features, vital for landslide mapping. Also, the easy repeatability of data acquisition offers the opportunity to monitor temporal surface changes, which are essential to identifying developing or active slides. Specific methods are needed to detect and map surface changes due to landslide activities. In this paper, we present a methodology that is based on fusing probabilistic change detection and landslide surface feature extraction utilizing multi-temporal Light Detection and Ranging (LiDAR derived Digital Elevation Models (DEMs to map surface changes demonstrating landslide activity. The proposed method was tested in an area with numerous slides ranging from 200 m2 to 27,000 m2 in area under low vegetation and tree cover, Zanesville, Ohio, USA. The surface changes observed are probabilistically evaluated to determine the likelihood of the changes being landslide activity related. Next, based on surface features, a Support Vector Machine (SVM quantifies and maps the topographic signatures of landslides in the entire area. Finally, these two processes are fused to detect landslide prone changes. The results demonstrate that 53 out of 80 inventory mapped landslides were identified using this method. Additionally, some areas that were not mapped in the inventory map displayed changes that are likely to be developing landslides.
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Frontally confined versus frontally emergent submarine landslides: A 3D seismic characterisation
Energy Technology Data Exchange (ETDEWEB)
Frey-Martinez, Jose; Cartwright, Joe; James, David [3DLab. School of Earth, Ocean and Planetary Sciences, Cardiff University, P.O. Box 914, Cardiff CF10 3YE (United Kingdom)
2006-06-15
Three-dimensional (3D) seismic data from the continental margin offshore Israel (Eastern Mediterranean) have been used to analyse the compressional structures within the toe regions of two major buried submarine landslides: the ISC and the T20. Both landslides are developed within a Plio-Pleistocene slope succession composed predominately of claystones, limestones and siltstones. The high spatial resolution provided by the seismic data has allowed a detailed analysis of the geometries and deformational structures within the toe regions of the two landslides, and this has been used to develop a mechanical model for their development. Importantly, it has been recognised that submarine landslides may be divided into two main types according to their form of frontal emplacement: frontally confined and frontally emergent. In the former, the landslide undergoes a restricted downslope translation and does not overrun the undeformed downslope strata. In the latter, much larger downslope translation occurs because the landslide is able to ramp up from its original basal shear surface and translate in an unconfined manner over the seafloor. We propose that these two types of submarine landslides are end members of a continuum of gravity-driven slope failure processes, which extends from landslides where the headscarp is completely evacuated, to landslides where the material remains entirely within the headscarp. The differentiation of these two end members is of critical importance as their respective mechanisms of formation, downslope propagation and emplacement are significantly different, and hence need to be taken into consideration when analysing their respective kinematics. (author)
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Exploring the utility of real-time hydrologic data for landslide early warning
Mirus, B. B.; Smith, J. B.; Becker, R.; Baum, R. L.; Koss, E.
2017-12-01
Early warning systems can provide critical information for operations managers, emergency planners, and the public to help reduce fatalities, injuries, and economic losses due to landsliding. For shallow, rainfall-triggered landslides early warning systems typically use empirical rainfall thresholds, whereas the actual triggering mechanism involves the non-linear hydrological processes of infiltration, evapotranspiration, and hillslope drainage that are more difficult to quantify. Because hydrologic monitoring has demonstrated that shallow landslides are often preceded by a rise in soil moisture and pore-water pressures, some researchers have developed early warning criteria that attempt to account for these antecedent wetness conditions through relatively simplistic storage metrics or soil-water balance modeling. Here we explore the potential for directly incorporating antecedent wetness into landslide early warning criteria using recent landslide inventories and in-situ hydrologic monitoring near Seattle, WA, and Portland, OR. We use continuous, near-real-time telemetered soil moisture and pore-water pressure data measured within a few landslide-prone hillslopes in combination with measured and forecasted rainfall totals to inform easy-to-interpret landslide initiation thresholds. Objective evaluation using somewhat limited landslide inventories suggests that our new thresholds based on subsurface hydrologic monitoring and rainfall data compare favorably to the capabilities of existing rainfall-only thresholds for the Seattle area, whereas there are no established rainfall thresholds for the Portland area. This preliminary investigation provides a proof-of-concept for the utility of developing landslide early warning criteria in two different geologic settings using real-time subsurface hydrologic measurements from in-situ instrumentation.
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Development of potential map for landslides by comparing instability indices of various time periods
Chiang, Jie-Lun; Tian, Yu-Qing; Chen, Yie-Ruey; Tsai, Kuang-Jung
2017-04-01
In recent years, extreme rainfall events occur frequently and induced serious landslides and debris flow disasters in Taiwan. The instability indices will differ when using landslide maps of different time periods. We analyzed the landslide records during the period year, 2008 2012, the landslide area contributed 0.42% 2.94% of the total watershed area, the 2.94% was caused by the typhoon Morakot in August, 2009, which brought massive rainfall in which the cumulative maximum rainfall was up to 2900 mm. We analyzed the instability factors including elevation, slope, aspect, soil, and geology. And comparing the instability indices by using individual landslide map of 2008 2012, the landslide maps of the union of the five years, and interaction of the five years. The landslide area from union of the five years contributed 3.71%,the landslide area from interaction of the five years contributed 0.14%. In this study, Kriging was used to establish the susceptibility map in selected watershed. From interaction of the five years, we found the instability index above 4.3 can correspond to those landslide records. The potential landslide area of the selected watershed, where collapses occur more likely, belongs to high level and medium-high level; the area is 13.43% and 3.04% respectively.
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Airborne laser scanning for forested landslides investigation in temperate and tropical environments
Razak, K.A.
2014-01-01
Landslide hazard and risk have increased over the last decades and pose a significant threat to modern society. Despite remarkable efforts of compiling and updating landslide maps at regional, national or global scales, the number of landslide events is often underestimated, especially in forested
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Landslide Spatial Distribution Analysis Using GIS. Case Study Secașelor Plateau.
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Gheorghe Rosian
2017-05-01
Full Text Available Landslides represent an extremely frequent geomorphological phenomenon in the Secașelor Plateau. The regional unit is located in the South-Eastern part of the Transylvanian Basin (large basin within the Carpathian Mountains. In this paper, we analyzed the distribution of the landslides through spatial statistics techniques and GIS. In order to analyze the distribution of the landslides we took into consideration 5 criteria: geology, height, slope, exposition and the territorial administrative units. This type of study is necessary to find out the way in which the actual landslides are distributed and on the other hand, the research will collect information on the susceptible fields which are favored by these geomorphological processes. After the visual analysis of the area using the 1:5000 aerial photography and topographic maps, 835 landslides were identified and vectorized. At the level of administrative-territorial units, these cover mostly agricultural areas. Given the lithological conditions (the presence of friable rocks of marl, clay and poorly cemented sands and the land use (mostly agricultural it can be said that in the future new landslides will ocure in similar conditions of slope, exposition and geological characteristic etc. The identification of areas that are susceptible to landslides is beneficial for the future territorial planning actions and also to avoid building on areas which are prone to landslides.
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Comparison of event landslide inventories: the Pogliaschina catchment test case, Italy
Mondini, A. C.; Viero, A.; Cavalli, M.; Marchi, L.; Herrera, G.; Guzzetti, F.
2014-07-01
Event landslide inventory maps document the extent of populations of landslides caused by a single natural trigger, such as an earthquake, an intense rainfall event, or a rapid snowmelt event. Event inventory maps are important for landslide susceptibility and hazard modelling, and prove useful to manage residual risk after a landslide-triggering event. Standards for the preparation of event landslide inventory maps are lacking. Traditional methods are based on the visual interpretation of stereoscopic aerial photography, aided by field surveys. New and emerging techniques exploit remotely sensed data and semi-automatic algorithms. We describe the production and comparison of two independent event inventories prepared for the Pogliaschina catchment, Liguria, Northwest Italy. The two inventories show landslides triggered by an intense rainfall event on 25 October 2011, and were prepared through the visual interpretation of digital aerial photographs taken 3 days and 33 days after the event, and by processing a very-high-resolution image taken by the WorldView-2 satellite 4 days after the event. We compare the two inventories qualitatively and quantitatively using established and new metrics, and we discuss reasons for the differences between the two landslide maps. We expect that the results of our work can help in deciding on the most appropriate method to prepare reliable event inventory maps, and outline the advantages and the limitations of the different approaches.
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Topographic registers of paleo-valleys on the southeastern Brazilian continental shelf
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Luis Américo Conti
2009-06-01
Full Text Available The evolution of paleo-incised-valleys in the São Paulo State region of the southeastern Brazilian continental shelf is presented in this study in relation to the post Last Glacial Maximum (LGM sea-level rises based on the submarine topography modeled by a detailed Digital Elevation Model and evidences noted in high resolution seismic profiles. The hypothesis that has guided this study is that the set of paleo-valley characteristics (i.e. the fluvial parameters of modern coastal drainage systems, the topographical shape and dimensions of the valleys and of the subsurface channels may indicate aspects of the relation between the influence of the fluvial and the eustatic variation regime in geomorphological-stratigraphic registers. Models described in the literature sustain the view that faster marine transgressions tend to increase erosion in estuaries, which may explain the lack of registers of paleo-drainage both in topography and the sub-surface in areas with wider shelves. On the other hand, on narrower shelves, with a higher slope angle, the transgression process can preserve, or even enhance, the incised valley registers during shoreface retreat. In the area studied, we observed that the dimensions and form of the continental shelf varies from the northern to the southern part of the area, affecting aspects of the geomorphological registers of the submerged incised valleys.Este trabalho apresenta aspectos da relação entre a evolução da paleo-drenagem e evolução do nível do mar pós Último Máximo Glacial (UMG para a região da plataforma continental do Estado de São Paulo. Para tal, foram analisados modelos topográficos de detalhe da região de Plataforma Continental a partir de Modelos Digitais de Terreno além de dados de subsuperfície obtidos a partir de linhas sísmicas de alta resolução. A hipótese que guiou este trabalho é de que o conjunto de características relativas aos paleo-vales (i.e. sua relação com a rede de
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Rainfall thresholds for the possible occurrence of landslides in Italy
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M. T. Brunetti
2010-03-01
Full Text Available In Italy, rainfall is the primary trigger of landslides that frequently cause fatalities and large economic damage. Using a variety of information sources, we have compiled a catalogue listing 753 rainfall events that have resulted in landslides in Italy. For each event in the catalogue, the exact or approximate location of the landslide and the time or period of initiation of the slope failure is known, together with information on the rainfall duration D, and the rainfall mean intensity I, that have resulted in the slope failure. The catalogue represents the single largest collection of information on rainfall-induced landslides in Italy, and was exploited to determine the minimum rainfall conditions necessary for landslide occurrence in Italy, and in the Abruzzo Region, central Italy. For the purpose, new national rainfall thresholds for Italy and new regional rainfall thresholds for the Abruzzo Region were established, using two independent statistical methods, including a Bayesian inference method and a new Frequentist approach. The two methods proved complementary, with the Bayesian method more suited to analyze small data sets, and the Frequentist method performing better when applied to large data sets. The new regional thresholds for the Abruzzo Region are lower than the new national thresholds for Italy, and lower than the regional thresholds proposed in the literature for the Piedmont and Lombardy Regions in northern Italy, and for the Campania Region in southern Italy. This is important, because it shows that landslides in Italy can be triggered by less severe rainfall conditions than previously recognized. The Frequentist method experimented in this work allows for the definition of multiple minimum rainfall thresholds, each based on a different exceedance probability level. This makes the thresholds suited for the design of probabilistic schemes for the prediction of rainfall-induced landslides. A scheme based on four
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Evidences of landslide earthquake triggering due to self-excitation process
Bozzano, F.; Lenti, L.; Martino, Salvatore; Paciello, A.; Scarascia Mugnozza, G.
2011-06-01
The basin-like setting of stiff bedrock combined with pre-existing landslide masses can contribute to seismic amplifications in a wide frequency range (0-10 Hz) and induce a self-excitation process responsible for earthquake-triggered landsliding. Here, the self-excitation process is proposed to justify the far-field seismic trigger of the Cerda landslide (Sicily, Italy) which was reactivated by the 6th September 2002 Palermo earthquake ( M s = 5.4), about 50 km far from the epicentre. The landslide caused damage to farm houses, roads and aqueducts, close to the village of Cerda, and involved about 40 × 106 m3 of clay shales; the first ground cracks due to the landslide movement formed about 30 min after the main shock. A stress-strain dynamic numerical modelling, performed by FDM code FLAC 5.0, supports the notion that the combination of local geological setting and earthquake frequency content played a fundamental role in the landslide reactivation. Since accelerometric records of the triggering event are not available, dynamic equivalent inputs have been used for the numerical modelling. These inputs can be regarded as representative for the local ground shaking, having a PGA value up to 0.2 m/s2, which is the maximum expected in 475 years, according to the Italian seismic hazard maps. A 2D numerical modelling of the seismic wave propagation in the Cerda landslide area was also performed; it pointed out amplification effects due to both the structural setting of the stiff bedrock (at about 1 Hz) and the pre-existing landslide mass (in the range 3-6 Hz). The frequency peaks of the resulting amplification functions ( A( f)) fit well the H/ V spectral ratios from ambient noise and the H/ H spectral ratios to a reference station from earthquake records, obtained by in situ velocimetric measurements. Moreover, the Fourier spectra of earthquake accelerometric records, whose source and magnitude are consistent with the triggering event, show a main peak at about 1 Hz
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Spatial Forecast of Landslides in Three Gorges Based On Spatial Data Mining
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Xianmin Wang
2009-03-01
Full Text Available The Three Gorges is a region with a very high landslide distribution density and a concentrated population. In Three Gorges there are often landslide disasters, and the potential risk of landslides is tremendous. In this paper, focusing on Three Gorges, which has a complicated landform, spatial forecasting of landslides is studied by establishing 20 forecast factors (spectra, texture, vegetation coverage, water level of reservoir, slope structure, engineering rock group, elevation, slope, aspect, etc. China-Brazil Earth Resources Satellite (Cbers images were adopted based on C4.5 decision tree to mine spatial forecast landslide criteria in Guojiaba Town (Zhigui County in Three Gorges and based on this knowledge, perform intelligent spatial landslide forecasts for Guojiaba Town. All landslides lie in the dangerous and unstable regions, so the forecast result is good. The method proposed in the paper is compared with seven other methods: IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance, Parallelepiped and Information Content Model. The experimental results show that the method proposed in this paper has a high forecast precision, noticeably higher than that of the other seven methods.
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Rainfall-induced landslides in Europe: hotspots and thresholds (Invited)
Cepeda, J.; Jaedicke, C.; Nadim, F.; Kalsnes, B.
2010-12-01
This contribution presents preliminary results of the European project SafeLand. SafeLand is a large-scale integrating collaborative research project on landslide risks in Europe, funded by the Seventh Framework Programme for research and technological development (FP7) of the European Commission. SafeLand was launched in May 2009 and will run for three years. The project team, which comprises 27 institutions from 12 European countries, is coordinated by the International Centre for Geohazards (ICG) in Norway. SafeLand aims to develop and implement an integrated and comprehensive approach to help and guide decision-making in connection with mitigation of landslide risks. Quantifying the effects of global change (changes in demography and climate change) on evolution of landslide risk in Europe is one of the main goals of SafeLand. The methodologies are tested in selected hazard and risk "hotspots” in Europe, in turn improving knowledge, methodologies and integration strategies for the management of landslide risk. The present contribution is focused on two components of SafeLand: (1) the identification of landslide hazard and risk hotspots and (2) the estimation and assessment of rainfall thresholds for triggering of landslides. Hotspots of landslide hazard and risk were identified by an objective GIS-based analysis. The results show clearly where landslide pose the largest hazard in Europe and the objective approach allows a ranking of the countries by exposed area and population. In absolute numbers, Italy is the country with the highest amount of area and population exposed. Relative to absolute number of inhabitants and area, small alpine countries such as Lichtenstein and Montenegro score highest where as much as 40% of the population could be exposed. It is obvious that the type and quality of the input data are decisive for the quality of the results. Especially the estimation of extreme precipitation events needs improvement. These preliminary results are
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GIS and statistical analysis for landslide susceptibility mapping in the Daunia area, Italy
Mancini, F.; Ceppi, C.; Ritrovato, G.
2010-09-01
This study focuses on landslide susceptibility mapping in the Daunia area (Apulian Apennines, Italy) and achieves this by using a multivariate statistical method and data processing in a Geographical Information System (GIS). The Logistic Regression (hereafter LR) method was chosen to produce a susceptibility map over an area of 130 000 ha where small settlements are historically threatened by landslide phenomena. By means of LR analysis, the tendency to landslide occurrences was, therefore, assessed by relating a landslide inventory (dependent variable) to a series of causal factors (independent variables) which were managed in the GIS, while the statistical analyses were performed by means of the SPSS (Statistical Package for the Social Sciences) software. The LR analysis produced a reliable susceptibility map of the investigated area and the probability level of landslide occurrence was ranked in four classes. The overall performance achieved by the LR analysis was assessed by local comparison between the expected susceptibility and an independent dataset extrapolated from the landslide inventory. Of the samples classified as susceptible to landslide occurrences, 85% correspond to areas where landslide phenomena have actually occurred. In addition, the consideration of the regression coefficients provided by the analysis demonstrated that a major role is played by the "land cover" and "lithology" causal factors in determining the occurrence and distribution of landslide phenomena in the Apulian Apennines.
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Geospatial Assessment of Coseismic Landslides in Baturagung Area
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Aditya Saputra
2016-02-01
Full Text Available Java, the most densely populated island in Indonesia, is located on top of the most seismically active areas in Southeast Asia: the Sunda Megathrust. This area is frequently hit by strong earthquake. More than 3,300 M>5earthquakesoccurred between 1973-2014. The wide range of mountainous areas and high intensity of rainfall, make several part of the island one of the most exposed regions for coseismic landslides such as Baturagung area, the Southeast mountainous area of Yogyakarta Province. An integrated method between RS and GIS was used to conduct the vulnerability assessment due to the lack of the site specific slope instability analysis and coseismic landslides data. The seismic zonation of Baturagung area was obtained based on the analysis of Kanai attenuation. The geologic information was extracted using remote sensing interpretation based on the 1:100,000 geologic map of Yogyakarta and geomorphologic map of Baturagung area as well. The coseismic landslide hazard assessment has been estimated using scoring analysis in the GIS platform proposed by Mora and Vahrson (1993 with several modification. The accomplished coseismic landslide hazard map shows medium hazard coverage in the eastern areas, in the upper slope of Baturagung area, which consists of Semilir Formation. The result provides a distinct description of coseismic landslides hazard distribution in Batuaragung area. However, it should only be the preliminary assessment of the site specific investigation especially on valuable area or asset.
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Y. Li
2012-08-01
Full Text Available A GIS-based method for the assessment of landslide susceptibility in a selected area of Qingchuan County in China is proposed by using the back-propagation Artificial Neural Network model (ANN. Landslide inventory was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as rainfall-induced landslides (RIL in this study, and 885 earthquake-induced landslides (EIL were recorded into the landslide inventory map. To understand the different impacts of rainfall and earthquake on landslide occurrence, we first compared the variations between landslide spatial distribution and conditioning factors. Then, we compared the weight variation of each conditioning factor derived by adjusting ANN structure and factors combination respectively. Last, the weight of each factor derived from the best prediction model was applied to the entire study area to produce landslide susceptibility maps.
Results show that slope gradient has the highest weight for landslide susceptibility mapping for both RIL and EIL. The RIL model built with four different factors (slope gradient, elevation, slope height and distance to the stream shows the best success rate of 93%; the EIL model built with five different factors (slope gradient, elevation, slope height, distance to the stream and distance to the fault has the best success rate of 98%. Furthermore, the EIL data was used to verify the RIL model and the success rate is 92%; the RIL data was used to verify the EIL model and the success rate is 53%. -
A review on the study of landslides triggered by rains
International Nuclear Information System (INIS)
Aristizabal E; Martinez H; Velez J I
2010-01-01
This article attempts to give a very detailed perspective to the challenge and advances associated to rainfall-triggered landslides, which are characteristic and very common in tropical environments, such as Colombia. Landslides are one of the most common hazards around the world. Economic losses caused by landslides are huge, and are often exaggerated due to urban sprawl. Recent findings in this topic around the world have been applied for determining critical thresholds by physical or statistical models, combined with rainfall forecasting and near real time monitoring as fundamental component of an early warning system. Landslides are caused by several phenomena, including geological, geomorphologic and anthropogenic dynamics; however, one variable - precipitation - has a uniquely strong capability to cause rapid, intense slope failure. A review of several studies of rainfall-triggered landslides is presented some of who have used statistical tools that define critical thresholds based on intensity and duration rainfall. Other authors have focused upon physical based models combining hydrological and geotechnical aspects of rainfall, water pore pressure and slope stability.
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Basin Scale Assessment of Landslides Geomorphological Setting by Advanced InSAR Analysis
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Francesca Bozzano
2017-03-01
Full Text Available An extensive investigation of more than 90 landslides affecting a small river basin in Central Italy was performed by combining field surveys and remote sensing techniques. We thus defined the geomorphological setting of slope instability processes. Basic information, such as landslides mapping and landslides type definition, have been acquired thanks to geomorphological field investigations and multi-temporal aerial photos interpretation, while satellite SAR archive data (acquired by ERS and Envisat from 1992 to 2010 have been analyzed by means of A-DInSAR (Advanced Differential Interferometric Synthetic Aperture Radar techniques to evaluate landslides past displacements patterns. Multi-temporal assessment of landslides state of activity has been performed basing on geomorphological evidence criteria and past ground displacement measurements obtained by A-DInSAR. This step has been performed by means of an activity matrix derived from information achieved thanks to double orbital geometry. Thanks to this approach we also achieved more detailed knowledge about the landslides kinematics in time and space.
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Duman, T. Y.; Can, T.; Gokceoglu, C.; Nefeslioglu, H. A.; Sonmez, H.
2006-11-01
As a result of industrialization, throughout the world, cities have been growing rapidly for the last century. One typical example of these growing cities is Istanbul, the population of which is over 10 million. Due to rapid urbanization, new areas suitable for settlement and engineering structures are necessary. The Cekmece area located west of the Istanbul metropolitan area is studied, because the landslide activity is extensive in this area. The purpose of this study is to develop a model that can be used to characterize landslide susceptibility in map form using logistic regression analysis of an extensive landslide database. A database of landslide activity was constructed using both aerial-photography and field studies. About 19.2% of the selected study area is covered by deep-seated landslides. The landslides that occur in the area are primarily located in sandstones with interbedded permeable and impermeable layers such as claystone, siltstone and mudstone. About 31.95% of the total landslide area is located at this unit. To apply logistic regression analyses, a data matrix including 37 variables was constructed. The variables used in the forwards stepwise analyses are different measures of slope, aspect, elevation, stream power index (SPI), plan curvature, profile curvature, geology, geomorphology and relative permeability of lithological units. A total of 25 variables were identified as exerting strong influence on landslide occurrence, and included by the logistic regression equation. Wald statistics values indicate that lithology, SPI and slope are more important than the other parameters in the equation. Beta coefficients of the 25 variables included the logistic regression equation provide a model for landslide susceptibility in the Cekmece area. This model is used to generate a landslide susceptibility map that correctly classified 83.8% of the landslide-prone areas.
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Digital inventory of landslides and related deposits in Honduras triggered by Hurricane Mitch
Harp, Edwin L.; Hagaman, Kirk W.; Held, Matthew D.; McKenna, Jonathan P.
2002-01-01
Intense rainfall from Hurricane Mitch from October 27-31, 1998, exceeded 900 mm in places in Honduras and triggered in excess of 500,000 landslides throughout the country. Landslides damaged an estimated 70% of the road network in Honduras based on estimates by the U. S Army Corps of Engineers. Numbers of fatalities due to landslides are not accurately known due to the fact that numerous small villages throughout Honduras lost residents to landslides without an official count being recorded. A conservative estimate would place the number at near 1,000. Debris flows accounted for over 95% of the landslides and ranged in thickness from 1 to 15 m. Flow path lengths of these failures ranged from several meters to 7.5 km. The highest concentrations of debris flows occurred in the mountains near the town of Choluteca where over 900 mm of rain fell in three days. Although landslides other than debris flows were few, several deep-seated landslides in the city of Tegucigalpa severely impacted people and property. The 'El Berrinche' rotational slump/earth flow of approximately six million cubic meters volume destroyed the entire neighborhood of Colonia Soto near the center of the city. The landslide also dammed the Rio Choluteca and created a lagoon behind the landslide dam, which immediately posed a health problem for the city, because raw, untreated sewage was emptying into the Rio Choluteca. Several areas of highly concentrated landslides have been responsible for much of the flooding problem as well. Huge sediment influxes from landslide source areas near La Ceiba, La Libertad, Marale, and in several arms of El Cajon Reservoir have reduced stream capacities to practically nothing and have exacerbated flooding conditions in even the moderate rainfall seasons since Hurricane Mitch. The ongoing hazard to communities from landslides triggered during Hurricane Mitch are being analyzed using aerial photography taken by the U.S. Air Force and by supplemental photography taken
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Directory of Open Access Journals (Sweden)
Lei Gui
2016-09-01
Full Text Available Slow moving landslide is a major disaster in the Three Gorges Reservoir area. It is difficult to compare the deformation among different parts of this kind of landslide through GPS measurements when the displacement of different monitoring points is similar in values. So far, studies have been seldom carried out to find out the information hidden behind those GPS monitoring data to solve this problem. Therefore, in this study, three landslides were chosen to perform landslide displacement analysis based on fractal theory. The major advantage of this study is that it has not only considered the values of the displacement of those GPS monitoring points, but also considered the moving traces of them. This allows to reveal more information from GPS measurements and to obtain a broader understanding of the deformation history on different parts of a unique landslide, especially for slow moving landslides. The results proved that using the fractal dimension as an indicator is reliable to estimate the deformation of each landslide and to represent landslide deformation on both spatial and temporal scales. The results of this study could make sense to those working on landslide hazard and risk assessment and land use planning.
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Hydrate-bearing Submarine Landslides in the Orca Basin, Gulf of Mexico
Sawyer, D.; Mason, A.; Cook, A.; Portnov, A.; Hillman, J.
2017-12-01
The co-occurrence of submarine landslides and hydrate-bearing sediment suggests that hydrates may play a role in landslide triggering and/or the mobility and dynamic characteristics of the submarine landslide. In turn, the removal of large sections of seafloor perturbs the hydrate stability field by removing overburden pressure and disturbing the temperature field. These potential hydrate-landslide feedbacks are not well understood. Here we combine three-dimensional seismic and petrophysical logs to characterize the deposits of submarine landslides that failed from hydrate-bearing sediments in the Orca Basin in the northern Gulf of Mexico. The Orca Basin contains a regionally mappable bottom simulating reflector, hydrate saturations within sands and muds, as well as numerous landslides. In addition, the Orca Basin features a well-known 123 km2 anoxic hypersaline brine pool that is actively being fed by outcropping salt. Lying at the bottom of the brine pool are deposits of submarine landslides. Slope instability in the Orca Basin is likely associated with near-seafloor salt tectonics. The most prominent landslide scar observable on the seafloor has a correlative deposit that now lies at the bottom of the brine pool 11.6 km away. The headwall is amphitheater-shaped with an average height of 80 meters and with only a minor amount of rubble remaining near the headwall. A total of 8.7 km3 of material was removed and deposited between the lower slopes of the basin and the base of the brine pool. Around the perimeter of the landslide headwall, two industry wells were drilled and well logs show elevated resistivity that are likely caused by gas hydrate. The slide deposits have a chaotic seismic facies with large entrained blocks and the headwall area does not retain much original material, which together suggests a relatively mobile style of landslide and therefore may have generated a wave upon impacting the brine pool. Such a slide-induced wave may have sloshed
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Directory of Open Access Journals (Sweden)
Christos Chalkias
2016-03-01
Full Text Available In this paper, an integration landslide susceptibility model by combining expert-based and bivariate statistical analysis (Landslide Susceptibility Index—LSI approaches is presented. Factors related with the occurrence of landslides—such as elevation, slope angle, slope aspect, lithology, land cover, Mean Annual Precipitation (MAP and Peak Ground Acceleration (PGA—were analyzed within a GIS environment. This integrated model produced a landslide susceptibility map which categorized the study area according to the probability level of landslide occurrence. The accuracy of the final map was evaluated by Receiver Operating Characteristics (ROC analysis depending on an independent (validation dataset of landslide events. The prediction ability was found to be 76% revealing that the integration of statistical analysis with human expertise can provide an acceptable landslide susceptibility assessment at regional scale.
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Landslides triggered by Hurricane Hugo in eastern Puerto Rico, September 1989
Larsen, Matthew C.; Torres-Sanchez, Angel J.
1992-01-01
On the morning of September 18, 1989, a category-four hurricane struck eastern Puerto Rico with a sustained wind speed in excess of 46 m/s. The 24-h rainfall accumulation from the hurricane ranged from 100 to 339 mm. Average rainfall intensities ranging from 34 to 39 mm/h were calculated for 4 and 6 h periods, respectively, at a rain gage equipped with satellite telemetry, and at an observer station. The hurricane rainfall triggered more than 400 landslides in the steeply sloping, highly dissected mountains of eastern Puerto Rico. Of these landslides, 285 were mapped from aerial photography which covered 6474 ha. Many of the mapped landslides were on northeast- and northwest-facing slopes at the eastern terminus of the mountains, nearest the hurricane path. The surface area of individual landslides ranged from 18 m2 to 4500 m2, with a median size of 148 m2. The 285 landslides disturbed 0.11% of the land surface in the area covered by aerial photographs. An approximate denudation rate of 164 mm/1000 y was calculated from the volume of material eroded by landsliding and the 10-y rainfall recurrence interval.
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Directory of Open Access Journals (Sweden)
Hyun-Joo Oh
2017-09-01
Full Text Available The main purpose of this paper is to present some potential applications of sophisticated data mining techniques, such as artificial neural network (ANN and boosted tree (BT, for landslide susceptibility modeling in the Yongin area, Korea. Initially, landslide inventory was detected from visual interpretation using digital aerial photographic maps with a high resolution of 50 cm taken before and after the occurrence of landslides. The debris flows were randomly divided into two groups: training and validation sets with a 50:50 proportion. Additionally, 18 environmental factors related to landslide occurrence were derived from the topography, soil, and forest maps. Subsequently, the data mining techniques were applied to identify the influence of environmental factors on landslide occurrence of the training set and assess landslide susceptibility. Finally, the landslide susceptibility indexes from ANN and BT were compared with a validation set using a receiver operating characteristics curve. The slope gradient, topographic wetness index, and timber age appear to be important factors in landslide occurrence from both models. The validation result of ANN and BT showed 82.25% and 90.79%, which had reasonably good performance. The study shows the benefit of selecting optimal data mining techniques in landslide susceptibility modeling. This approach could be used as a guideline for choosing environmental factors on landslide occurrence and add influencing factors into landslide monitoring systems. Furthermore, this method can rank landslide susceptibility in urban areas, thus providing helpful information when selecting a landslide monitoring site and planning land-use.
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Drop Height and Volume Control the Mobility of Long-Runout Landslides on the Earth and Mars
Johnson, Brandon C.; Campbell, Charles S.
2017-12-01
Long-runout landslides are landslides with volumes of 105 m3 or more, which move much farther from their source than expected. The observation that Martian landslides are generally less mobile than terrestrial landslides offers important evidence regarding the mechanism responsible for the high mobility of long-runout landslides. Here we simulate landslides as granular flow using a soft-particle discrete element model. We show that while surface gravity plays a negligible role, observed differences in fall height naturally reproduce the observed differences in mobility of Martian and terrestrial landslides. We also demonstrate that landslides on Iapetus may fit this trend. Our simulations do not include any fluid and indicate that a mechanism similar to acoustic fluidization can explain the high mobility of long-runout landslides. This implies that long-runout landslides on Mars should not be considered as evidence for ice, saturated clays, or liquid water.
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DTMs Assessment to the Definition of Shallow Landslides Prone Areas
Martins, Tiago D.; Oka-Fiori, Chisato; Carvalho Vieira, Bianca; Montgomery, David R.
2017-04-01
Predictive methods have been developed, especially since the 1990s, to identify landslide prone areas. One of the examples it is the physically based model SHALSTAB (Shallow Landsliding Stability Model), that calculate the potential instability for shallow landslides based on topography and physical soil properties. Normally, in such applications in Brazil, the Digital Terrain Model (DTM), is obtained mainly from conventional contour lines. However, recently the LiDAR (Light Detection and Ranging) system has been largely used in Brazil. Thus, this study aimed to evaluate different DTM's, generated from conventional data and LiDAR, and their influence in generating susceptibility maps to shallow landslides using SHALSTAB model. For that were analyzed the physical properties of soil, the response of the model when applying conventional topographical data and LiDAR's in the generation of DTM, and the shallow landslides susceptibility maps based on different topographical data. The selected area is in the urban perimeter of the municipality of Antonina (PR), affected by widespread landslides in March 2011. Among the results, it was evaluated different LiDAR data interpolation, using GIS tools, wherein the Triangulation/Natural Neighbor presented the best performance. It was also found that in one of evaluation indexes (Scars Concentration), the LiDAR derived DTM presented the best performance when compared with the one originated from contour lines, however, the Landslide Potential index, has presented a small increase. Consequently, it was possible to assess the DTM's, and the one derived from LiDAR improved very little the certitude percentage. It is also noted a gap in researches carried out in Brazil on the use of products generated from LiDAR data on geomorphological analysis.
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The impacts of formative system on the landslides of Iran
Directory of Open Access Journals (Sweden)
Mojgan Entezari Najafabadi
2012-04-01
Full Text Available Landslide is one of the most challenging disasters on the earth, which is believed to cause other natural catastrophic incidents. Normally, in studying landslide we investigate different influencing factors such as gender land, atmospheric rainfall, gradients’ change, earthquake, volcanic eruption, subterranean water vibration, and human causes in the form of different models. These facts are blamed as the main share in appearing this phenomenon. However, correlative and sufficient condition for genesis such a phenomenon is historical base of lands’ bed, which needs specific formative process. There are several studies focused on distribution and dispersion of slides and their reasons. In this paper, we investigate the behavior of landslide and its effects on instigating instabilities. The preliminary results indicate that distribution of this phenomenon is associated with climate from a side and historical formative process on the other side. The weather condition of Iran is divided into four groups of cold, hot, humid and humid hot hole. Every region has its own special geomorphic properties and either directly or indirectly affects on landslide occurrence. In order to study this effect, we use Arc GIS 9.3 software dispersal map of Iran’s main landslides and formative systems on the other side and by local analyzing these two collections are evaluated based on their vicinity relationship using local-statistical techniques. Results of this research shows that the main part of this landslide occurs in cold hole and humid hole and only about 8 percent are happens in hot holl. In addition, density of landslides are more in thermodynamic bound of cold and hot hole as well as cold and humid hole.
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The 3D Elevation Program—Landslide recognition, hazard assessment, and mitigation support
Lukas, Vicki; Carswell, Jr., William J.
2017-01-27
The U.S. Geological Survey (USGS) Landslide Hazards Program conducts landslide hazard assessments, pursues landslide investigations and forecasts, provides technical assistance to respond to landslide emergencies, and engages in outreach. All of these activities benefit from the availability of high-resolution, three-dimensional (3D) elevation information in the form of light detection and ranging (lidar) data and interferometric synthetic aperture radar (IfSAR) data. Research on landslide processes addresses critical questions of where and when landslides are likely to occur as well as their size, speed, and effects. This understanding informs the development of methods and tools for hazard assessment and situational awareness used to guide efforts to avoid or mitigate landslide impacts. Such research is essential for the USGS to provide improved information on landslide potential associated with severe storms, earthquakes, volcanic activity, coastal wave erosion, and wildfire burn areas.Decisionmakers in government and the private sector increasingly depend on information the USGS provides before, during, and following disasters so that communities can live, work, travel, and build safely. The USGS 3D Elevation Program (3DEP) provides the programmatic infrastructure to generate and supply lidar-derived superior terrain data to address landslide applications and a wide range of other urgent needs nationwide. By providing data to users, 3DEP reduces users’ costs and risks and allows them to concentrate on their mission objectives. 3DEP includes (1) data acquisition partnerships that leverage funding, (2) contracts with experienced private mapping firms, (3) technical expertise, lidar data standards, and specifications, and (4) most important, public access to high-quality 3D elevation data.
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Tsunamis generated by long and thin granular landslides in a large flume
Miller, Garrett S.; Andy Take, W.; Mulligan, Ryan P.; McDougall, Scott
2017-01-01
In this experimental study, granular material is released down slope to investigate landslide-generated waves. Starting with a known volume and initial position of the landslide source, detailed data are obtained on the velocity and thickness of the granular flow, the shape and location of the submarine landslide deposit, the amplitude and shape of the near-field wave, the far-field wave evolution, and the wave runup elevation on a smooth impermeable slope. The experiments are performed on a 6.7 m long 30° slope on which gravity accelerates the landslides into a 2.1 m wide and 33.0 m long wave flume that terminates with a 27° runup ramp. For a fixed landslide volume of 0.34 m3, tests are conducted in a range of still water depths from 0.05 to 0.50 m. Observations from high-speed cameras and measurements from wave probes indicate that the granular landslide moves as a long and thin train of material, and that only a portion of the landslide (termed the "effective mass") is engaged in activating the leading wave. The wave behavior is highly dependent on the water depth relative to the size of the landslide. In deeper water, the near-field wave behaves as a stable solitary-like wave, while in shallower water, the wave behaves as a breaking dissipative bore. Overall, the physical model observations are in good agreement with the results of existing empirical equations when the effective mass is used to predict the maximum near-field wave amplitude, the far-field amplitude, and the runup of tsunamis generated by granular landslides.
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Analysis of landslide overgrowing rates at Vaskiny Dachi key site, Central Yamal, Russia
Khomutov, A.
2009-04-01
An estimation of overgrowing of landslide-affected slopes by vegetation at three main landslide elements: shear surface, landslide body and "frontal zone" at Vaskiny Dachi key site is presented. Vaskiny Dachi key site is located in the watershed of Se-Yakha and Mordy-Yakha rivers on Central Yamal, Russia. The area is represented by highly-dissected alluvial-lacustrine-marine plains and terraces. The closest to Vaskiny Dachi climate station is Marresale, about 90 km southwest of Vaskiny Dachi, at the Kara sea coast. The weather here is probably somewhat cooler than at Vaskiny Dachi. The average annual (summer) air temperature at Marresale is -8.3° C (4.3° C) ("Russia's Weather" Server). To estimate vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi", data published by O.Rebristaya and others (1995) were used. Their observations were done in 1991-1993, and were supplemented by further field observations (Leibman et al., 2000, Khomutov & Leibman 2007) and by field and remote sensing observations in 2008. An estimation of vegetation cover dynamics on cryogenic landslides at "Vaskiny Dachi" leads to the following results. Immediately after landsliding in 1989, landslide shear surface was bare without any vegetation, landslide body had initial vegetation, and "frontal zone" was under liquefied sediment masses. "Frontal zone" formed in front of a landslide body, appears as a result of damming of drainage routes by a landslide body with flooding of the shear surface "upstream" of the landslide body, formation of a sedge-cottongrass meadow there, and swamping downstream (Khomutov & Leibman 2007). By 1993, landslide shear surface got overgrown by species subordinate in surrounding initial landscapes (Alopecurus alpinus, Festuca ovina, Calamagrostis neglecta, Poa alpigena ssp. Alpigena, etc.). Landslide body was covered by initial communities which got depressed: vitality of Salix polaris, Vaccinium vitis-idaea was reduced, dead off moss cover and overgrown
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Krieger, Medora Louise Hooper
1977-01-01
The landslides in the Kearny and El Capitan Mountain quadrangles, Pinal and Gila Counties, Ariz., are tabular or lens like masses of megabreccia enclosed in Miocene basin deposits. The megabreccias within individual slide blocks are composed of pervasively brecciated Precambrian and younger formations that remain in normal stratigraphic sequence, indicating that each landslide moved as a fairly coherent mass. The megabreccias consist of fresh, mostly angular rock fragments in a comminuted matrix of the same composition as the fragments. The matrix ranges in amount from sparse to abundant. Where the matrix is sparse, the fragments fit tightly with little or no rotation. Locally fragments are rotated but not moved far; most units within a slide block are lithologically homogeneous. The Kearny landslides are conformably interbedded in steeply east-dipping playa and alluvial deposits. They form map units from a few tens of meters to nearly 4 km long and from less than 1 to 270 m wide. Narrow ridges expose sections through the landslides at about right angles to the direction of movement. The upper (proximal) ends have been eroded; the lower (distal) ends are buried. The El Capitan landslide dips very gently southward. Although partly dissected during erosion of the enclosing alluvial and lakebed deposits, its approximate original outline is still preserved. It forms a thin sheet, 5-15 m thick and at least 3.8 km long; the maximum outcrop width, near its distal end, is about 1.5 km. The Kearny landslides show little evidence of having exerted differential pressure on the underlying soft playa and alluvial deposits, and the contacts with the underlying sediments have little relief. The distal end of the El Capitan landslide, on the other hand, has considerable relief. As the landslide came to an abrupt stop, the end plowed into the underlying sediments, compressing them into fol9.s and forming sandstone dikes. The source of the El Capitan landslide is a well
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Booth, Adam M.; Roering, Josh J.; Rempel, Alan W.
2013-06-01
A fundamental goal of studying earth surface processes is to disentangle the complex web of interactions among baselevel, tectonics, climate, and rock properties that generate characteristic landforms. Mechanistic geomorphic transport laws can quantitatively address this goal, but no widely accepted law for landslides exists. Here we propose a transport law for deep-seated landslides in weathered bedrock and demonstrate its utility using a two-dimensional numerical landscape evolution model informed by study areas in the Waipaoa catchment, New Zealand, and the Eel River catchment, California. We define a non-dimensional landslide number, which is the ratio of the horizontal landslide flux to the vertical tectonic flux, that characterizes three distinct landscape types. One is dominated by stochastic landsliding, whereby discrete landslide events episodically erode material at rates exceeding the long-term uplift rate. Another is characterized by steady landsliding, in which the landslide flux at any location remains constant through time and is greatest at the steepest locations in the catchment. The third is not significantly affected by landsliding. In both the "stochastic landsliding" and "steady landsliding" regimes, increases in the non-dimensional landslide number systematically reduce catchment relief and widen valley spacing, producing long, low angle hillslopes despite high uplift rates. The stochastic landsliding regime captures the frequent observation that deep-seated landslides produce large sediment fluxes from small areal extents while being active only a fraction of the time. We suggest that this model is adaptable to a wide range of geologic settings and is useful for interpreting climate-driven changes in landslide behavior.
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Suppressing geo-facts in landslide-affected areas
Sajinkumar, Ks; Pradeepkumar, Ap; Rani, Vr; Di Capua, Giuseppe
2014-05-01
The Western Ghats, the bold westerly escarpment of India and which borders the eastern portion of Kerala State (India), bears the testimony of frequent landslides, especially during the monsoon season, and they cause widespread damage to life and property. The natural hazards can turn into disasters in this hilly state, due to the high density of population (~800 per km2). The elements at landslide risk in any area include human population, livestock, land and its resources, environmental values, buildings and economic activities. The loss of lives is the most heart breaking side of the story and cannot be compensated in pecuniary terms. The role of the geoscientist comes into picture to protect the life and property from imminent landslides. But the unbiased role of a geoscientist is blocked by several societal issues like fear of disapproval by the public, political interference, false information propagated through the fourth estate and last but not the least the lack of confidence in her/himself as the profession is now mainly non-societal. This paper aims at looking into these issues in a landslide-prone area of the state. The deontological vs consequential ethical behaviours that characterise the responses by the official machinery and the common man conspire to create disastrous situations, which ultimately brings suffering to the common man, while straining the resources of the state through recurrent payment of damages, every year. The "moral vs monetary" values of society and its government is laid bare in Kerala, especially during landslide disasters and the state's social contract obligations sometimes become ambiguous. Another aspect that has to be addressed is the impact on the marginalized during landslide disasters in Kerala. Does the newly instituted 'Disaster Insurance' scheme adequately cover them? What is the ethical dimensions that such schemes address? The Kerala state is the most socially, educationally, and demographically advanced one in
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A Database of Historical Information on Landslides and Floods in Italy
Guzzetti, F.; Tonelli, G.
2003-04-01
For the past 12 years we have maintained and updated a database of historical information on landslides and floods in Italy, known as the National Research Council's AVI (Damaged Urban Areas) Project archive. The database was originally designed to respond to a specific request of the Minister of Civil Protection, and was aimed at helping the regional assessment of landslide and flood risk in Italy. The database was first constructed in 1991-92 to cover the period 1917 to 1990. Information of damaging landslide and flood event was collected by searching archives, by screening thousands of newspaper issues, by reviewing the existing technical and scientific literature on landslides and floods in Italy, and by interviewing landslide and flood experts. The database was then updated chiefly through the analysis of hundreds of newspaper articles, and it now covers systematically the period 1900 to 1998, and non-systematically the periods 1900 to 1916 and 1999 to 2002. Non systematic information on landslide and flood events older than 20th century is also present in the database. The database currently contains information on more than 32,000 landslide events occurred at more than 25,700 sites, and on more than 28,800 flood events occurred at more than 15,600 sites. After a brief outline of the history and evolution of the AVI Project archive, we present and discuss: (a) the present structure of the database, including the hardware and software solutions adopted to maintain, manage, use and disseminate the information stored in the database, (b) the type and amount of information stored in the database, including an estimate of its completeness, and (c) examples of recent applications of the database, including a web-based GIS systems to show the location of sites historically affected by landslides and floods, and an estimate of geo-hydrological (i.e., landslide and flood) risk in Italy based on the available historical information.
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The landslide database for Germany: Closing the gap at national level
Damm, Bodo; Klose, Martin
2015-11-01
The Federal Republic of Germany has long been among the few European countries that lack a national landslide database. Systematic collection and inventory of landslide data still has a long research history in Germany, but one focussed on the development of databases with local or regional coverage. This has changed in recent years with the launch of a database initiative aimed at closing the data gap existing at national level. The present paper reports on this project that is based on a landslide database which evolved over the last 15 years to a database covering large parts of Germany. A strategy of systematic retrieval, extraction, and fusion of landslide data is at the heart of the methodology, providing the basis for a database with a broad potential of application. The database offers a data pool of more than 4,200 landslide data sets with over 13,000 single data files and dates back to the 12th century. All types of landslides are covered by the database, which stores not only core attributes, but also various complementary data, including data on landslide causes, impacts, and mitigation. The current database migration to PostgreSQL/PostGIS is focused on unlocking the full scientific potential of the database, while enabling data sharing and knowledge transfer via a web GIS platform. In this paper, the goals and the research strategy of the database project are highlighted at first, with a summary of best practices in database development providing perspective. Next, the focus is on key aspects of the methodology, which is followed by the results of three case studies in the German Central Uplands. The case study results exemplify database application in the analysis of landslide frequency and causes, impact statistics, and landslide susceptibility modeling. Using the example of these case studies, strengths and weaknesses of the database are discussed in detail. The paper concludes with a summary of the database project with regard to previous
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Submarine landslide: A case study from the southwestern of Taiwan offshore
Hung, Y. H.; Dong, J. J.
2016-12-01
Based on the new multibeam bathymetric data and seismic reflection profiles of the southwestern Taiwan, more and more submarine landslides developed there have been being discovered nowadays. Palm Ridge, located between the boundary of the active and passive margins, is the place where a deformation front passes through. And previous studies suspected that there were old submarine landslides developed here. To learn whether there are old submarine landslides here, a further study is conducted with the collection and analysis of new high-resolution swath-bathymetry and seismic data. Firstly, based on the swath-bathymetry, the topography range of the landslide is mapped and interpreted with the three dimensional model. Then, according to the profile of the mapping, the extending of the sliding surface is predicted. And referred on the properties of soil in adjacent region, the engineering geologic models of the landslide before and after failure are proposed. Thirdly, through a detailed analysis of the seismic data of Taiwan in the past three decades, a magnitude of 7.7 MW is selected as the lower bound of earthquake for the analysis of the trigger of the submarine landslide. And based on the record of earthquakes with 8 MW in the world, some other earthquake magnitudes are also considered in this study. After applying them into STABL 5M, the failure process of the landslide is modeled with its possible deposited ranges being reached. Finally, the sub-bottom and seismic data are used to verify the rationality of the above results. Preliminary result shows that there were at least three landslides occurred in Palm Ridge. The first landslide is largest which covers the approximate range of the study area. The second one is developed in the margin area of the first one, which is resulted by the occurrence of the first one. The third event is caused by the further collapse of the first one due to the loose of its inner structure.
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Precipitation thresholds for landslide occurrence near Seattle, Mukilteo, and Everett, Washington
Scheevel, Caroline R.; Baum, Rex L.; Mirus, Benjamin B.; Smith, Joel B.
2017-04-27
Shallow landslides along coastal bluffs frequently occur in the railway corridor between Seattle and Everett, Washington. These slides disrupt passenger rail service, both because of required track maintenance and because the railroad owner, Burlington Northern Santa Fe Railway, does not allow passenger travel for 48 hours after a disruptive landslide. Sound Transit, which operates commuter trains in the corridor, is interested in a decision-making tool to help preemptively cancel passenger railway service in dangerous conditions and reallocate resources to alternative transportation.Statistical analysis showed that a majority of landslides along the Seattle-Everett Corridor are strongly correlated with antecedent rainfall, but that 21-37 percent of recorded landslide dates experienced less than 1 inch of precipitation in the 3 days preceding the landslide and less than 4 inches of rain in the 15 days prior to the preceding 3 days. We developed two empirical thresholds to identify precipitation conditions correlated with landslide occurrence. The two thresholds are defined as P3 = 2.16-0.44P15 and P3 = 2.16-0.22P32, where P3 is the cumulative precipitation in the 3 days prior to the considered date and P15 or P32 is the cumulative precipitation in the 15 days or 32 days prior to P3 (all measurements given in inches). The two thresholds, when compared to a previously developed threshold, quantitatively improve the prediction rate.We also investigated rainfall intensity-duration (ID) thresholds to determine whether revision would improve identification of moderate-intensity, landslide-producing storms. New, optimized ID thresholds evaluate rainstorms lasting at least 12 hours and identify landslide-inducing storms that were typically missed by previously published ID thresholds. The main advantage of the ID thresholds appears when they are combined with recent-antecedent thresholds because rainfall conditions that exceed both threshold types are more likely to induce
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Rahardianto, Trias; Saputra, Aditya; Gomez, Christopher
2017-07-01
Research on landslide susceptibility has evolved rapidly over the few last decades thanks to the availability of large databases. Landslide research used to be focused on discreet events but the usage of large inventory dataset has become a central pillar of landslide susceptibility, hazard, and risk assessment. Indeed, extracting meaningful information from the large database is now at the forth of geoscientific research, following the big-data research trend. Indeed, the more comprehensive information of the past landslide available in a particular area is, the better the produced map will be, in order to support the effective decision making, planning, and engineering practice. The landslide inventory data which is freely accessible online gives an opportunity for many researchers and decision makers to prevent casualties and economic loss caused by future landslides. This data is advantageous especially for areas with poor landslide historical data. Since the construction criteria of landslide inventory map and its quality evaluation remain poorly defined, the assessment of open source landslide inventory map reliability is required. The present contribution aims to assess the reliability of open-source landslide inventory data based on the particular topographical setting of the observed area in Niigata prefecture, Japan. Geographic Information System (GIS) platform and statistical approach are applied to analyze the data. Frequency ratio method is utilized to model and assess the landslide map. The outcomes of the generated model showed unsatisfactory results with AUC value of 0.603 indicate the low prediction accuracy and unreliability of the model.
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Albrecht, Florian; Weinke, Elisabeth; Eisank, Clemens; Vecchiotti, Filippo; Hölbling, Daniel; Friedl, Barbara; Kociu, Arben
2017-04-01
Regional authorities and infrastructure maintainers in almost all mountainous regions of the Earth need detailed and up-to-date landslide inventories for hazard and risk management. Landslide inventories usually are compiled through ground surveys and manual image interpretation following landslide triggering events. We developed a web service that uses Earth Observation (EO) data to support the mapping and monitoring tasks for improving the collection of landslide information. The planned validation of the EO-based web service does not only cover the analysis of the achievable landslide information quality but also the usability and user friendliness of the user interface. The underlying validation criteria are based on the user requirements and the defined tasks and aims in the work description of the FFG project Land@Slide (EO-based landslide mapping: from methodological developments to automated web-based information delivery). The service will be validated in collaboration with stakeholders, decision makers and experts. Users are requested to test the web service functionality and give feedback with a web-based questionnaire by following the subsequently described workflow. The users will operate the web-service via the responsive user interface and can extract landslide information from EO data. They compare it to reference data for quality assessment, for monitoring changes and for assessing landslide-affected infrastructure. An overview page lets the user explore a list of example projects with resulting landslide maps and mapping workflow descriptions. The example projects include mapped landslides in several test areas in Austria and Northern Italy. Landslides were extracted from high resolution (HR) and very high resolution (VHR) satellite imagery, such as Landsat, Sentinel-2, SPOT-5, WorldView-2/3 or Pléiades. The user can create his/her own project by selecting available satellite imagery or by uploading new data. Subsequently, a new landslide
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Landslide Geohazard Monitoring, Early Warning and Stabilization Control Methods
Directory of Open Access Journals (Sweden)
Bednarczyk Zbigniew
2014-03-01
Full Text Available This paper is a presentation of landslide monitoring, early warning and remediation methods recommended for the Polish Carpathians. Instrumentation included standard and automatic on-line measurements with the real-time transfer of data to an Internet web server. The research was funded through EU Innovative Economy Programme and also by the SOPO Landslide Counteraction Project. The landslides investigated were characterized by relatively low rates of the displacements. These ranged from a few millimetres to several centimetres per year. Colluviums of clayey flysch deposits were of a soil-rock type with a very high plasticity and moisture content. The instrumentation consisted of 23 standard inclinometers set to depths of 5-21 m. The starting point of monitoring measurements was in January 2006. These were performed every 1-2 months over the period of 8 years. The measurements taken detected displacements from several millimetres to 40 cm set at a depth of 1-17 m. The modern, on-line monitoring and early warning system was installed in May 2010. The system is the first of its kind in Poland and only one of several such real-time systems in the world. The installation was working with the Local Road Authority in Gorlice. It contained three automatic field stations for investigation of landslide parameters to depths of 12-16 m and weather station. In-place tilt transducers and innovative 3D continuous inclinometer systems with sensors located every 0.5 m were used. It has the possibility of measuring a much greater range of movements compared to standard systems. The conventional and real-time data obtained provided a better recognition of the triggering parameters and the control of geohazard stabilizations. The monitoring methods chosen supplemented by numerical modelling could lead to more reliable forecasting of such landslides and could thus provide better control and landslide remediation possibilities also to stabilization works which
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Regional rainfall thresholds for landslide occurrence using a centenary database
Vaz, Teresa; Luís Zêzere, José; Pereira, Susana; Cruz Oliveira, Sérgio; Quaresma, Ivânia
2017-04-01
Rainfall is one of the most important triggering factors for landslides occurrence worldwide. The relation between rainfall and landslide occurrence is complex and some approaches have been focus on the rainfall thresholds identification, i.e., rainfall critical values that when exceeded can initiate landslide activity. In line with these approaches, this work proposes and validates rainfall thresholds for the Lisbon region (Portugal), using a centenary landslide database associated with a centenary daily rainfall database. The main objectives of the work are the following: i) to compute antecedent rainfall thresholds using linear and potential regression; ii) to define lower limit and upper limit rainfall thresholds; iii) to estimate the probability of critical rainfall conditions associated with landslide events; and iv) to assess the thresholds performance using receiver operating characteristic (ROC) metrics. In this study we consider the DISASTER database, which lists landslides that caused fatalities, injuries, missing people, evacuated and homeless people occurred in Portugal from 1865 to 2010. The DISASTER database was carried out exploring several Portuguese daily and weekly newspapers. Using the same newspaper sources, the DISASTER database was recently updated to include also the landslides that did not caused any human damage, which were also considered for this study. The daily rainfall data were collected at the Lisboa-Geofísico meteorological station. This station was selected considering the quality and completeness of the rainfall data, with records that started in 1864. The methodology adopted included the computation, for each landslide event, of the cumulative antecedent rainfall for different durations (1 to 90 consecutive days). In a second step, for each combination of rainfall quantity-duration, the return period was estimated using the Gumbel probability distribution. The pair (quantity-duration) with the highest return period was
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Paleo-Environmental Reconstruction Using Ancient DNA
DEFF Research Database (Denmark)
Pedersen, Mikkel Winther
The aim of this thesis has been to investigate and expand the methodology and applicability for using ancient DNA deposited in lake sediments to detect and determine its genetic sources for paleo-environmental reconstruction. The aim was furthermore to put this tool into an applicable context...... solving other scientifically interesting questions. Still in its childhood, ancient environmental DNA research has a large potential for still developing, improving and discovering its possibilities and limitations in different environments and for identifying various organisms, both in terms...... research on ancient and modern environmental DNA (Paper 1), secondly by setting up a comparative study (Paper 2) to investigate how an ancient plant DNA (mini)-barcode can reflect other traditional methods (e.g. pollen and macrofossils) for reconstructing floristic history. In prolongation of the results...
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Impact of landsliding on chemical weathering in the volcanic island of Reunion
Gayer, E.; Lucas, A.; Bouchez, J.; Sy, A.; Louvat, P.; Gaillardet, J.; Dosseto, A.; Kuessner, M.; Michon, L.; Yokochi, R.
2017-12-01
Tropical precipitation regimes allow for strong erosion that creates dramatic landscapes. Understanding and quantifying erosion processes in tropical volcanic islands is important for both scientific challenges (e.g. regarding their implications for global biogeochemical cycles and their links with climate) and societal matters (e.g. socio-economic and ecosystem damages in highly populated areas). Despite the fact that the link between chemical weathering and physical erosion has long been studied, most research has focused on active mountain ranges. Here we use Reunion Island as a natural laboratory to explore this link in a tectonically inactive environment.In Reunion, estimates show that intense erosion rates are mainly due to stochastic bedrock landsliding. Although landslides affect only a small portion of the landscape they supply rivers with huge amounts of fresh broken rocks and organic matter, which are then available for chemical alteration and for transport. In this study, we measured water chemistry of several streams in Reunion and of landslide seepage water sampled on 2 majors landslides ("Grand Éboulis" and "Mahavel", both > 50 yrs old). Seepage samples from Grand Éboulis show high Total Dissolved Solids (TDS) compared to local streams, in agreement with previous observations showing that landslides promote chemical weathering [1]. However, the low TDS of the Mahavel seep water samples compared to local streams, suggest that the impact of landslides on weathering fluxes may strongly depend on the rate at which landslide debris are transferred downstream and their subsequent residence time in the catchment. In order to calculate such sediment transfer rates in Mahavel, we developed an automated photogrammetric workflow allowing for deriving Digital Elevation Models from historical aerial photos. Using the 30 years of images archived at the Institut Geographique National (5 campaigns), we will be able to delineate the extent of landslide debris, to
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A cusp catastrophe model of mid-long-term landslide evolution over low latitude highlands of China
Tao, Yun; Cao, Jie; Hu, Jinming; Dai, Zhicheng
2013-04-01
Based on a model describing a certain landslide case and catastrophe theory, we derived a cusp catastrophe model and corresponding inversion method to study mid-long-term landslide evolution. According to data of landslides, precipitation, and socioeconomic development from 1976 to 2008, the cusp catastrophe model describing this landslide evolution across a low-latitude highland area in China is obtained with the least squares method. Results of the model indicate that human activity determines landslide intensity. Local precipitation also impacts yearly landslide intensity to some extent, and controls the time when a strong and abrupt change in landslides occurs. During the period 1976-2008, there was an abrupt decrease of landslide intensity during 1994-1995, and an abrupt increase during 1995-1996. Since then, there have been frequent landslides in the low-latitude highland, with greater intensity. All these factors provide a scientific basis for formulating a contingency plan regarding landslide disasters.
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Role of land use change in landslide-related sediment fluxes in tropical mountain regions
Guns, M.; Vanacker, V.; Demoulin, A.
2012-04-01
Tropical mountain regions are characterised by high denudation rates. Landslides are known to be recurrent phenomena in active mountain belts, but their contribution to the overall sedimentary fluxes is not yet well known. Previous studies on sedimentary cascades have mostly focused on natural environments, without considering the impact of human and/or anthropogenic disturbances on sedimentary budgets. In our work, we hypothesise that human-induced land use change might alter the sediment cascade through shifts in the landslide magnitude-frequency relationship. We have tested this assumption in the Virgen Yacu catchment (approximately 11km2), in the Ecuadorian Cordillera Occidental. Landslide inventories and land use maps were established based on a series of sequential aerial photos (1963, 1977, 1984 and 1989), a HR Landsat image (2001) and a VHR WorldView2 image (2010). Aerial photographs were ortho-rectified, and coregistred with the WorldView2 satellite image. Field campaigns were realised in 2010 and 2011 to collect field-based data on landslide type and geometry (depth, width and length). This allowed us to establish an empirical relationship between landslide area and volume, which was then applied to the landslide inventories to estimate landslide-related sediment production rates for various time periods. The contribution of landslides to the overall sediment flux of the catchment was estimated by comparing the landslide-related sediment production to the total sediment yield. The empirical landslide area-volume relationship established here for the Ecuadorian Andes is similar to that derived for the Himalayas. It suggests that landslides are the main source of sediment in this mountainous catchment. First calculations indicate that human-induced land use change alters the magnitude-frequency relationship through strong increase of small landslides.
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Milledge, David G; Bellugi, Dino; McKean, Jim A; Densmore, Alexander L; Dietrich, William E
2014-11-01
The size of a shallow landslide is a fundamental control on both its hazard and geomorphic importance. Existing models are either unable to predict landslide size or are computationally intensive such that they cannot practically be applied across landscapes. We derive a model appropriate for natural slopes that is capable of predicting shallow landslide size but simple enough to be applied over entire watersheds. It accounts for lateral resistance by representing the forces acting on each margin of potential landslides using earth pressure theory and by representing root reinforcement as an exponential function of soil depth. We test our model's ability to predict failure of an observed landslide where the relevant parameters are well constrained by field data. The model predicts failure for the observed scar geometry and finds that larger or smaller conformal shapes are more stable. Numerical experiments demonstrate that friction on the boundaries of a potential landslide increases considerably the magnitude of lateral reinforcement, relative to that due to root cohesion alone. We find that there is a critical depth in both cohesive and cohesionless soils, resulting in a minimum size for failure, which is consistent with observed size-frequency distributions. Furthermore, the differential resistance on the boundaries of a potential landslide is responsible for a critical landslide shape which is longer than it is wide, consistent with observed aspect ratios. Finally, our results show that minimum size increases as approximately the square of failure surface depth, consistent with observed landslide depth-area data.
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Effects of natural conditions on development of a landslide at a mining area
Energy Technology Data Exchange (ETDEWEB)
Palki, J
1982-01-01
Investigations show that 39.4% of landslides at the mining ground in the Rybnik coal region is caused by factors other than underground mining. Determining the actual cause of a landslide is of importance for an underground mine because, as a rule, all ground damage is claimed to be caused by underground mining. A case of a landslide in the Rybnik area is analyzed. Landslide development is shown in a photo and 17 schemes. Ground morphology, water conditions and effects of underground longwall mining are evaluated. The analyses show that ground subsidence caused by underground mining ranging from 2.0 m to 3.1 m reduced the angle of slope inclination preventing more intensive landslides. Intensity of horizontal deformation was too low to cause a landslide. Slope stability decrease was caused by loose rock layers (sands) at the base of a hill. Accumulation of atmospheric precipitation and disturbed water outflow caused an increase in the plasticity of the sand. Mechanical vibrations caused by train traffic on tracks located close to the slope were an additional factor causing landslide development. (6 refs.)
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Directory of Open Access Journals (Sweden)
M. Ercanoglu
2005-01-01
Full Text Available Landslides are significant natural hazards in Turkey, second only to earthquakes with respect to economic losses and casualties. The West Black Sea region of Turkey is known as one of the most landslide-prone regions in the country. The work presented in this paper is aimed at evaluating landslide susceptibility in a selected area in the West Black Sea region using Artificial Neural Network (ANN method. A total of 317 landslides were identified and mapped in the area by extensive field work and by use of air photo interpretations to build a landslide inventory map. A landslide database was then derived automatically from the landslide inventory map. To evaluate landslide susceptibility, six input parameters (slope angle, slope aspect, topographical elevation, topographical shape, wetness index, and vegetation index were used. To obtain maps of these parameters, Digital Elevation Model (DEM and ASTER satellite imagery of the study area were used. At the first stage, all data were normalized in [0, 1] interval, and parameter effects on landslide occurrence were expressed using Statistical Index values (Wi. Then, landslide susceptibility analyses were performed using an ANN. Finally, performance of the resulting map and the applied methodology is discussed relative to performance indicators, such as predicted areal extent of landslides and the strength of relation (rij value. Much of the areal extents of the landslides (87.2% were classified as susceptible to landsliding, and rij value of 0.85 showed a high degree of similarity. In addition to these, at the final stage, an independent validation strategy was followed by dividing the landslide data set into two parts and 82.5% of the validation data set was found to be correctly classified as landslide susceptible areas. According to these results, it is concluded that the map produced by the ANN is reliable and methodology applied in the study produced high performance, and satisfactory results.
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Remote Sensing for Landslide Investigations: An Overview of Recent Achievements and Perspectives
Directory of Open Access Journals (Sweden)
Marco Scaioni
2014-10-01
Full Text Available Landslides represent major natural hazards, which cause every year significant loss of lives and damages to buildings, properties and lifelines. In the last decades, a significant increase in landslide frequency took place, in concomitance to climate change and the expansion of urbanized areas. Remote sensing techniques represent a powerful tool for landslide investigation: applications are traditionally divided into three main classes, although this subdivision has some limitations and borders are sometimes fuzzy. The first class comprehends techniques for landslide recognition, i.e., the mapping of past or active slope failures. The second regards landslide monitoring, which entails both ground deformation measurement and the analysis of any other changes along time (e.g., land use, vegetation cover. The third class groups methods for landslide hazard analysis and forecasting. The aim of this paper is to give an overview on the applications of remote-sensing techniques for the three categories of landslide investigations, focusing on the achievements of the last decade, being that previous studies have already been exhaustively reviewed in the existing literature. At the end of the paper, a new classification of remote-sensing techniques that may be pertinently adopted for investigating specific typologies of soil and rock slope failures is proposed.
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Major risk from rapid, large-volume landslides in Europe (EU Project RUNOUT)
Kilburn, Christopher R. J.; Pasuto, Alessandro
2003-08-01
Project RUNOUT has investigated methods for reducing the risk from large-volume landslides in Europe, especially those involving rapid rates of emplacement. Using field data from five test sites (Bad Goisern and Köfels in Austria, Tessina and Vajont in Italy, and the Barranco de Tirajana in Gran Canaria, Spain), the studies have developed (1) techniques for applying geomorphological investigations and optical remote sensing to map landslides and their evolution; (2) analytical, numerical, and cellular automata models for the emplacement of sturzstroms and debris flows; (3) a brittle-failure model for forecasting catastrophic slope failure; (4) new strategies for integrating large-area Global Positioning System (GPS) arrays with local geodetic monitoring networks; (5) methods for raising public awareness of landslide hazards; and (6) Geographic Information System (GIS)-based databases for the test areas. The results highlight the importance of multidisciplinary studies of landslide hazards, combining subjects as diverse as geology and geomorphology, remote sensing, geodesy, fluid dynamics, and social profiling. They have also identified key goals for an improved understanding of the physical processes that govern landslide collapse and runout, as well as for designing strategies for raising public awareness of landslide hazards and for implementing appropriate land management policies for reducing landslide risk.
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Lacroix, P.; Perfettini, H.; Taipe, E.; Guillier, B.
2014-10-01
We document the first time series of a landslide reactivation by an earthquake using continuous GPS measurements over the Maca landslide (Peru). Our survey shows a coseismic response of the landslide of about 2 cm, followed by a relaxation period of 5 weeks during which postseismic slip is 3 times greater than the coseismic displacement itself. Our results confirm the coseismic activation of landslides and provide the first observation of a postseismic displacement. These observations are consistent with a mechanical model where slip on the landslide basal interface is governed by rate and state friction, analogous to the mechanics of creeping tectonic faults, opening new perspectives to study the mechanics of landslides and active faults.
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Landslide hazard mapping with selected dominant factors: A study case of Penang Island, Malaysia
International Nuclear Information System (INIS)
Tay, Lea Tien; Alkhasawneh, Mutasem Sh.; Ngah, Umi Kalthum; Lateh, Habibah
2015-01-01
Landslide is one of the destructive natural geohazards in Malaysia. In addition to rainfall as triggering factos for landslide in Malaysia, topographical and geological factors play important role in the landslide susceptibility analysis. Conventional topographic factors such as elevation, slope angle, slope aspect, plan curvature and profile curvature have been considered as landslide causative factors in many research works. However, other topographic factors such as diagonal length, surface area, surface roughness and rugosity have not been considered, especially for the research work in landslide hazard analysis in Malaysia. This paper presents landslide hazard mapping using Frequency Ratio (FR) and the study area is Penang Island of Malaysia. Frequency ratio approach is a variant of probabilistic method that is based on the observed relationships between the distribution of landslides and each landslide-causative factor. Landslide hazard map of Penang Island is produced by considering twenty-two (22) landslide causative factors. Among these twenty-two (22) factors, fourteen (14) factors are topographic factors. They are elevation, slope gradient, slope aspect, plan curvature, profile curvature, general curvature, tangential curvature, longitudinal curvature, cross section curvature, total curvature, diagonal length, surface area, surface roughness and rugosity. These topographic factors are extracted from the digital elevation model of Penang Island. The other eight (8) non-topographic factors considered are land cover, vegetation cover, distance from road, distance from stream, distance from fault line, geology, soil texture and rainfall precipitation. After considering all twenty-two factors for landslide hazard mapping, the analysis is repeated with fourteen dominant factors which are selected from the twenty-two factors. Landslide hazard map was segregated into four categories of risks, i.e. Highly hazardous area, Hazardous area, Moderately hazardous area
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Landslide hazard mapping with selected dominant factors: A study case of Penang Island, Malaysia
Energy Technology Data Exchange (ETDEWEB)
Tay, Lea Tien; Alkhasawneh, Mutasem Sh.; Ngah, Umi Kalthum [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Lateh, Habibah [School of Distance Education, Universiti Sains Malaysia, 11600 Penang (Malaysia)
2015-05-15
Landslide is one of the destructive natural geohazards in Malaysia. In addition to rainfall as triggering factos for landslide in Malaysia, topographical and geological factors play important role in the landslide susceptibility analysis. Conventional topographic factors such as elevation, slope angle, slope aspect, plan curvature and profile curvature have been considered as landslide causative factors in many research works. However, other topographic factors such as diagonal length, surface area, surface roughness and rugosity have not been considered, especially for the research work in landslide hazard analysis in Malaysia. This paper presents landslide hazard mapping using Frequency Ratio (FR) and the study area is Penang Island of Malaysia. Frequency ratio approach is a variant of probabilistic method that is based on the observed relationships between the distribution of landslides and each landslide-causative factor. Landslide hazard map of Penang Island is produced by considering twenty-two (22) landslide causative factors. Among these twenty-two (22) factors, fourteen (14) factors are topographic factors. They are elevation, slope gradient, slope aspect, plan curvature, profile curvature, general curvature, tangential curvature, longitudinal curvature, cross section curvature, total curvature, diagonal length, surface area, surface roughness and rugosity. These topographic factors are extracted from the digital elevation model of Penang Island. The other eight (8) non-topographic factors considered are land cover, vegetation cover, distance from road, distance from stream, distance from fault line, geology, soil texture and rainfall precipitation. After considering all twenty-two factors for landslide hazard mapping, the analysis is repeated with fourteen dominant factors which are selected from the twenty-two factors. Landslide hazard map was segregated into four categories of risks, i.e. Highly hazardous area, Hazardous area, Moderately hazardous area
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Tatard, Lucile; Villacorta, Sandra; Metzger, Pascale
2013-04-01
85% of people exposed to earthquakes, hurricanes, floods and drought live in developing countries (IPU, 2010). This population is also exposed to the landslide risk as this phenomenon is mainly triggered by earthquakes and rainfall. There is an urgent need to propose methods to evaluate and mitigate the landslide risk for developing countries, where few studies were undergone and data, and information on data, are scarce. In this study, we characterize a landslide inventory set up for the megalopolis of Lima, Peru, by the local geological bureau (INGEMMET). This inventory was set up using satellite images and includes landslides of all ages. It is composed of two landslide types: rockfalls and debris flows (huaycos) that we investigate together and separately. First, we describe qualitatively the landslide occurrences in terms of geology, slope steepness, altitude, etc. We notably find that debris flows occur at altitudes larger than the ones of the rockfalls, probably due to the climatic conditions. Then we find that the rockfalls and debris flows area distributions follow a power law when investigated separately whereas it does not follow a power law when investigated together. This highlights a logical difference of mechanics between the two landslide types. Then, using the dimension of correlation D (Grassberger and Procaccia, 1983) we show that the event spatial occurrences are not uniformly distributed but clustered. It supports the existence of controlling parameters on the spatial occurrence of landslides and the research to identify them. Last, we investigate the relationships between different landslide parameters (geology, altitude, slope steepness, ...) using the linear correlation coefficient r, and we find that all these parameters are independent to each other. This allows us to investigate each parameter separately in terms of landslide susceptibility and to define values for which the landslide susceptibility is low, medium or high for each
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Large eruption-triggered ocean-island landslide at Tenerife
DEFF Research Database (Denmark)
Harris, P; Branney, M; Storey, Michael
2011-01-01
An extensive debris-avalanche deposit has been discovered on Cañadas volcano, Tenerife (Canary Islands). The onshore component of the 733 ± 3 ka Abona landslide deposit exposes classic block facies and mixed facies across 90 km2. Three lines of evidence together show that the avalanche was trigge......An extensive debris-avalanche deposit has been discovered on Cañadas volcano, Tenerife (Canary Islands). The onshore component of the 733 ± 3 ka Abona landslide deposit exposes classic block facies and mixed facies across 90 km2. Three lines of evidence together show that the avalanche...... was triggered by an ignimbrite-forming explosive eruption: (1) the deposit is enclosed by phonolitic ignimbrites and is draped by a Plinian fallout layer, all within a single eruption unit; (2) it contains prismatic-jointed pumice blocks that were hot during landslide emplacement, indicated by chilled rims...... and breadcrust surfaces; (3) these blocks yield the same 40Ar/39Ar date as the associated ignimbrite and fall deposit. Landslide hummocks dammed surface water, forming ephemeral lakes perched on the volcano flank. Phonolite dome growth destabilized the southeast sector of a mid-Pleistocene Cañadas caldera wall...
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Automated reconstruction of rainfall events responsible for shallow landslides
Vessia, G.; Parise, M.; Brunetti, M. T.; Peruccacci, S.; Rossi, M.; Vennari, C.; Guzzetti, F.
2014-04-01
Over the last 40 years, many contributions have been devoted to identifying the empirical rainfall thresholds (e.g. intensity vs. duration ID, cumulated rainfall vs. duration ED, cumulated rainfall vs. intensity EI) for the initiation of shallow landslides, based on local as well as worldwide inventories. Although different methods to trace the threshold curves have been proposed and discussed in literature, a systematic study to develop an automated procedure to select the rainfall event responsible for the landslide occurrence has rarely been addressed. Nonetheless, objective criteria for estimating the rainfall responsible for the landslide occurrence (effective rainfall) play a prominent role on the threshold values. In this paper, two criteria for the identification of the effective rainfall events are presented: (1) the first is based on the analysis of the time series of rainfall mean intensity values over one month preceding the landslide occurrence, and (2) the second on the analysis of the trend in the time function of the cumulated mean intensity series calculated from the rainfall records measured through rain gauges. The two criteria have been implemented in an automated procedure written in R language. A sample of 100 shallow landslides collected in Italy by the CNR-IRPI research group from 2002 to 2012 has been used to calibrate the proposed procedure. The cumulated rainfall E and duration D of rainfall events that triggered the documented landslides are calculated through the new procedure and are fitted with power law in the (D,E) diagram. The results are discussed by comparing the (D,E) pairs calculated by the automated procedure and the ones by the expert method.
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Devoli, Graziella
2008-01-01
The thesis investigates and proposes a suitable form of collecting, organizing and analysing landslide data in order to improve the knowledge of landslide processes in Central America. The study recommends the organization of existing and new data in a national landslide database for Nicaragua in a digital format. The database is intended to support the scientific community and local and national authorities in landslide hazard assessment, emergency management, land-use planning and the devel...
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Community Capacity in The Face Of Landslide Hazards in the Southern Of Semarang City
Tjahjono, Heri; Suripin; Kismartini
2018-02-01
The study was done at Semarang, Central Java. The aims of the study are: (a) to know the variation in the level of community capacity in dealing with landslide hazards in the southern of Semarang city; (B) to know the factors that affect the capacity of communities in facing the hazards of landslides. This research was conducted by the sample method with a sample of 198 people, taken by purposive sampling. Samples taken are people living in areas that have experienced landslide or in areas that are expected to be vulnerable to landslides. The variables used in this research are (1) regulatory and institutional capacity in the prevention of landslide disaster, (2) early warning system in community, (3) education of disaster skill training, (4) mitigation to reduce basic risk factor, and (5) Preparedness on all fronts. Data were collected with questioner and interviews. Data analysis was performed by percentage descriptions, and map overlay analysis using ArcGIS release 10.3 technology. The result of the research shows that there are 5 variations of society's capacity level in facing the landslide hazard in southern Semarang city, that is the very high capacity of society as much as 4,35 % of the people that researched, the high community capacity is 7,25 % of the people that researched, the medium community capacity is 30.43 %. of the people that researched, low community capacity as much as 36.23 % of the people that researched and very low community capacity as much as 21.74% of the people that researched. Based on the result of overlay map of landslide threat in southern Semarang City with map about variation of community capacity level in facing landslide hazard indicate that community capacity with very high criterion and high occupancy area of threat of landslide with high and medium criterion which have been experienced landslide. While the capacity of the community with the criteria of medium, low and very low occupies the threat of landslide areas with high
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Landslides risk mitigation along lifelines
Capparelli, G.; Versace, P.; Artese, G.; Costanzo, S.; Corsonello, P.; Di Massa, G.; Mendicino, G.; Maletta, D.; Leone, S.; Muto, F.; Senatore, A.; Troncone, A.; Conte, E.; Galletta, D.
2012-04-01
The paper describes an integrated, innovative and efficient solution to manage risk issues associated to landslides interfering with infrastructures. The research project was submitted for financial support in the framework of the Multi -regional Operational Programme 2007-13: Research and Competitiveness funded by the Ministry of Research (MIUR) and co-funded by the European Regional Development Fund. The project is aimed to developing and demonstrating an integrated system of monitoring, early warning and mitigation of landslides risk. The final goal is to timely identify potentially dangerous landslides, and to activate all needed impact mitigation measures, including the information delivery. The essential components of the system include monitoring arrays, telecommunication networks and scenario simulation models, assisted by a data acquisition and processing centre, and a traffic control centres. Upon integration, the system will be experimentally validated and demonstrated over ca. 200 km of three highway sections, crossing the regions of Campania, Basilicata, Calabria and Sicily. Progress in the state of art is represented by the developments in the field of environmental monitoring and in the mathematical modeling of landslides and by the development of services for traffic management. The approach to the problem corresponds to a "systemic logics" where each developed component foresees different interchangeable technological solutions to maximize the operational flexibility. The final system may be configured as a simple to complex structure, including different configurations to deal with different scenarios. Specifically, six different monitoring systems will be realized: three "point" systems, made up of a network of locally measuring sensors, and three "area" systems to remotely measure the displacements of large areas. Each network will be fully integrated and connected to a unique data transmission system. Standardized and shared procedures for the
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Evaluation of Landslide Mapping Techniques and LiDAR-based Conditioning Factors
Mahalingam, R.; Olsen, M. J.
2014-12-01
Landslides are a major geohazard, which result in significant human, infrastructure, and economic losses. Landslide susceptibility mapping can help communities to plan and prepare for these damaging events. Mapping landslide susceptible locations using GIS and remote sensing techniques is gaining popularity in the past three decades. These efforts use a wide variety of procedures and consider a wide range of factors. Unfortunately, each study is often completed differently and independently of others. Further, the quality of the datasets used varies in terms of source, data collection, and generation, which can propagate errors or inconsistencies into the resulting output maps. Light detection and ranging (LiDAR) has proved to have higher accuracy in representing the continuous topographic surface, which can help minimize this uncertainty. The primary objectives of this paper are to investigate the applicability and performance of terrain factors in landslide hazard mapping, determine if LiDAR-derived datasets (slope, slope roughness, terrain roughness, stream power index and compound topographic index) can be used for predictive mapping without data representing other common landslide conditioning factors, and evaluate the differences in landslide susceptibility mapping using widely-used statistical approaches. The aforementioned factors were used to produce landslide susceptibility maps for a 140 km2 study area in northwest Oregon using six representative techniques: frequency ratio, weights of evidence, logistic regression, discriminant analysis, artificial neural network, and support vector machine. Most notably, the research showed an advantage in selecting fewer critical conditioning factors. The most reliable factors all could be derived from a single LiDAR DEM, reducing the need for laborious and costly data gathering. Most of the six techniques showed similar statistical results; however, ANN showed less accuracy for predictive mapping. Keywords : Li
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Harp, E.L.
1993-01-01
The generation of seismically induced landslide depends on the characteristics of shaking as well as mechanical properties of geologic materials. A very important parameter in the study of seismically induced landslide is the intensity based on a strong-motion accelerogram: it is defined as Arias intensity and is proportional to the duration of the shaking record as well as the amplitude. Having a theoretical relationship between Arias intensity, magnitude and distance it is possible to predict how far away from the seismic source landslides are likely to occur for a given magnitude earthquake. Field investigations have established that the threshold level of Arias intensity depends also on site effects, particularly the fracture characteristics of the outcrops present. -from Author
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Rainfall-induced landslide susceptibility zonation of Puerto Rico
Chiara Lepore; Sameer A. Kamal; Peter Shanahan; Rafael L. Bras
2011-01-01
Landslides are a major geologic hazard with estimated tens of deaths and $1â2 billion in economic losses per year in the US alone. The island of Puerto Rico experiences one or two large events per year, often triggered in steeply sloped areas by prolonged and heavy rainfall. Identifying areas susceptible to landslides thus has great potential value for Puerto Rico and...
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Characterization of groundwater dynamics in landslides in varved clays
Van der Spek, J.E.; Bogaard, T.A.; Bakker, M.
2013-01-01
Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trieves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and
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Delineation of potential deep seated landslides in a watershed using environmental index
Lai, Siao Ying; Lin, Chao Yuan; Lin, Cheng Yu
2016-04-01
The extreme rainfall induced deep seated landslides cause more attentions recently. Extreme rainfall can accelerate soil moisture content and surface runoff in slopeland which usually results in severe headward erosion and slope failures in an upstream watershed. It's a crucial issue for disaster prevention to extract the sites of potential deep seated landslide dynamically. Landslide risk and scale in a watershed were well discussed in this study. Risk of landslide occurrence in a watershed can be calculated from the multiplication of hazard and vulnerability for a certain event. A synthesis indicator derived from the indices of inverted extreme rainfall, road development and inverted normalized difference vegetation index can be effectively used as vulnerability for a watershed before the event. Landslide scale estimated from the indices of soil depth, headward erosion, river concave and dip slope could be applied to locate the hotspots of deep seated landslide in a watershed. The events of Typhoon Morakot in 2009 and Soudelor in 2015 were also selected in this study to verify the delineation accuracy of the model for the references of related authorities.
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Segmentation and Classification of Nepal Earthquake Induced Landslides Using SENTINEL-1 Product
Kunwar, Saket
2016-06-01
On April 26, 2015, an earthquake of magnitude 7.8 on the Richter scale occurred, with epicentre at Barpak (28°12'20''N,84°44'19''E), Nepal. Landslides induced due to the earthquake and its aftershock added to the natural disaster claiming more than 9000 lives. Landslides represented as lines that extend from the head scarp to the toe of the deposit were mapped by the staff of the British Geological Survey and is available freely under Open Data Commons Open Database License(ODC-ODbL) license at the Humanitarian Data Exchange Program. This collection of 5578 landslides is used as preliminary ground truth in this study with the aim of producing polygonal delineation of the landslides from the polylines via object oriented segmentation. Texture measures from Sentinel-1a Ground Range Detected (GRD) Amplitude data and eigenvalue-decomposed Single Look Complex (SLC) polarimetry product are stacked for this purpose. This has also enabled the investigation of landslide properties in the H-Alpha plane, while developing a classification mechanism for identifying the occurrence of landslides.
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Landslides Triggered by the 12 May 2008, M 7.9 Wenchuan, China Earthquake
Harp, E.; Jibson, R.; Godt, J.
2009-04-01
The 12 May 2008, M 7.9 Wenchuan earthquake in eastern Sichuan Province of China triggered tens of thousands of rock falls, rock slides, rock avalanches, and deep, complex, landslides. Of the approximately 87,000 deaths caused by the earthquake, more than 20,000 have been attributed to landsides. Numerous villages were buried by large landslides. Air-blasts resulting from the rapid failure and movement of landslides were observed and documented from numerous eye-witness accounts. More than 100 landslide-dammed lakes were created by the earthquake, 33 of which were evaluated to determine if spillway construction was necessary to minimize flooding by future breaching of the landslide dams. Spillways were ultimately constructed on at least 16 landslide dams. Preliminary observations in the field and from satellite imagery indicate that the most common types of landslides were rock falls and rock slides that ranged in size from several hundred cubic meters to several hundred thousand cubic meters in volume. There were hundreds to perhaps as many as one thousand landslides exceeding 1 million cubic meters in volume. The largest landslide identified using Jaxa's Alos/Prism satellite imagery (2.5 m resolution) is nearly 1 billion cubic meters in volume and is located approximately 12 km north-northeast of the city of Hanwang. This landslide appears to have resulted from the failure of a 1.5-km section of ridge crest that now occupies most of the adjacent valley to the northeast; its toe spills over the next ridge crest to the northeast. The satellite imagery of 4 June 2008 shows two small lakes dammed by the slide debris. Within the mountainous areas in the near-field zone of shaking, rock slides dammed chains of lakes in many drainages. Sections of streams 2-3 km long have been completely covered by rock debris as of the 4 June imagery The debris from the triggered landslides is being redistributed rapidly by post-earthquake rainfall. A 100-year rainstorm in September
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Sezer, Ebru; Pradhan, Biswajeet; Gokceoglu, Candan
2010-05-01
Landslides are one of the recurrent natural hazard problems throughout most of Malaysia. Recently, the Klang Valley area of Selangor state has faced numerous landslide and mudflow events and much damage occurred in these areas. However, only little effort has been made to assess or predict these events which resulted in serious damages. Through scientific analyses of these landslides, one can assess and predict landslide-susceptible areas and even the events as such, and thus reduce landslide damages through proper preparation and/or mitigation. For this reason , the purpose of the present paper is to produce landslide susceptibility maps of a part of the Klang Valley areas in Malaysia by employing the results of the adaptive neuro-fuzzy inference system (ANFIS) analyses. Landslide locations in the study area were identified by interpreting aerial photographs and satellite images, supported by extensive field surveys. Landsat TM satellite imagery was used to map vegetation index. Maps of topography, lineaments and NDVI were constructed from the spatial datasets. Seven landslide conditioning factors such as altitude, slope angle, plan curvature, distance from drainage, soil type, distance from faults and NDVI were extracted from the spatial database. These factors were analyzed using an ANFIS to construct the landslide susceptibility maps. During the model development works, total 5 landslide susceptibility models were obtained by using ANFIS results. For verification, the results of the analyses were then compared with the field-verified landslide locations. Additionally, the ROC curves for all landslide susceptibility models were drawn and the area under curve values was calculated. Landslide locations were used to validate results of the landslide susceptibility map and the verification results showed 98% accuracy for the model 5 employing all parameters produced in the present study as the landslide conditioning factors. The validation results showed sufficient
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Directory of Open Access Journals (Sweden)
D. Gauthier
2012-11-01
Full Text Available Heavy rains spread over some interval preceding large landslides in sensitive glaciomarine clay in eastern Canada are often noted as a triggering or causative factor in case studies or research reports for individual landslides, although the quantity or duration of the triggering rain event has never been characterized adequately. We selected five large landslide events that occurred in the glaciomarine clay in eastern Canada, and calculated cumulative antecedent precipitation for intervals ranging between one and 365 days preceding each event. We also calculated the antecedent precipitation values for every other day in the record, and computed the relative rank of the landslide day within the complete record. Our results show that several intervals for each landslide event are highly ranked – including those preceding a presumably earthquake-triggered landslide – but overall the rankings were highly variable, ranging between 99% and 6%. The set of highest-ranking intervals are unique for each event, including both short and long-term cumulative precipitation. All of the landslides occurred in the spring months, and the release of sequestered surface and ground water during the spring ground thaw may be related to the timing of the large landslides, so that the evolution of ground frost in the early winter may be of interest for landslide prediction. We found no simple precipitation threshold for triggering large landslides in sensitive glaciomarine clay in eastern Canada, suggesting that some complex temporal and spatial combination of pre-conditions, external energy (e.g. earthquakes, precipitation triggers and other factors such as ground frost formation and thaw are required to trigger a landslide.
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Effects of large deep-seated landslides on hillslope morphology, western Southern Alps, New Zealand
Korup, Oliver
2006-03-01
Morphometric analysis and air photo interpretation highlight geomorphic imprints of large landslides (i.e., affecting ≥1 km2) on hillslopes in the western Southern Alps (WSA), New Zealand. Large landslides attain kilometer-scale runout, affect >50% of total basin relief, and in 70% are slope clearing, and thus relief limiting. Landslide terrain shows lower mean local relief, relief variability, slope angles, steepness, and concavity than surrounding terrain. Measuring mean slope angle smoothes out local landslide morphology, masking any relationship between large landslides and possible threshold hillslopes. Large failures also occurred on low-gradient slopes, indicating persistent low-frequency/high-magnitude hillslope adjustment independent of fluvial bedrock incision. At the basin and hillslope scale, slope-area plots partly constrain the effects of landslides on geomorphic process regimes. Landslide imprints gradually blend with relief characteristics at orogen scale (102 km), while being sensitive to length scales of slope failure, topography, sampling, and digital elevation model resolution. This limits means of automated detection, and underlines the importance of local morphologic contrasts for detecting large landslides in the WSA. Landslide controls on low-order drainage include divide lowering and shifting, formation of headwater basins and hanging valleys, and stream piracy. Volumes typically mobilized, yet still stored in numerous deposits despite high denudation rates, are >107 m3, and theoretically equal to 102 years of basin-wide debris production from historic shallow landslides; lack of absolute ages precludes further estimates. Deposit size and mature forest cover indicate residence times of 101-104 years. On these timescales, large landslides require further attention in landscape evolution models of tectonically active orogens.
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Multi - band Persistent Scatterer Interferometry data integration for landslide analysis
Bianchini, Silvia; Mateos, Rosa; Mora, Oscar; García, Inma; Sánchez, Ciscu; Sanabria, Margarita; López, Maite; Mulas, Joaquin; Hernández, Mario; Herrera, Gerardo
2013-04-01
We present a methodology to perform a geomorphological assessment of ground movements over wide areas, by improving Persistent Scatterer Interferometry (PSI) analysis for landslide studies. The procedure relies on the integrated use of multi-band EO data acquired by different satellite sensors in different time intervals, to provide a detailed investigation of ground displacements. The methodology, throughout the cross-comparison and integration of PS data in different microwave bands (ALOS in L-band, ERS1/2 and ENVISAT in C-band, COSMOSKY-MED in X-band), is applied on the Tramontana Range in the northwestern part of Mallorca island (Spain), extensively affected by mass movements across time, especially during the last years. We increase the confidence degree of the available interferometric data and we homogenize all PS targets by implementing and classifying them through common criteria. Therefore, PSI results are combined with geo-thematic data and pre-existing landslide inventories of the study area, in order to improve the landslide database, providing additional information on the detected ground displacements. The results of this methodology are used to elaborate landslide activity maps, permitting to jointly exploit heterogeneous PS data for analyzing landslides at regional scale. Moreover, from a geomorphological perspective, the proposed approach exploits the implemented PS data to achieve a reliable spatial analysis of movement rates, whatever referred to certain landslide phenomena or to other natural processes, in order to perform ground motion activity maps within a wide area.
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Landslide in claystone derived soil
Energy Technology Data Exchange (ETDEWEB)
Richardson, A M
1979-07-01
This article describes a landslide that occured in the Pittsburgh area in a soil deposit derived from the Pittsburgh Redbed Claystone when a cut was made at the toe. (The Pittsburgh Redbed Claystone is the parent of much of the soil material involved in the Pittsburgh area and occurs about mid way between the base of Pittsburgh Coal and the top of the Upper Freepost Coal). The topography before the slide was known and the geometry of the slide mass was established. Slope stability analysis indicated that the landslide could have been predicted using effective stress-shear-strength parameters of s of 12 to 13 and c is 0, where s is angle of shearing resistance and c is cohesion intercept in terms of effective stresses.
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Rapid post-seismic landslide evacuation boosted by dynamic river width
Croissant, Thomas; Lague, Dimitri; Steer, Philippe; Davy, Philippe
2017-09-01
Mass wasting caused by large-magnitude earthquakes chokes mountain rivers with several cubic kilometres of sediment. The timescale and mechanisms by which rivers evacuate small to gigantic landslide deposits are poorly known, but are critical for predicting post-seismic geomorphic hazards, interpreting the signature of earthquakes in sedimentary archives and deciphering the coupling between erosion and tectonics. Here, we use a new 2D hydro-sedimentary evolution model to demonstrate that river self-organization into a narrower alluvial channel overlying the bedrock valley dramatically increases sediment transport capacity and reduces export time of gigantic landslides by orders of magnitude compared with existing theory. Predicted export times obey a universal non-linear relationship of landslide volume and pre-landslide valley transport capacity. Upscaling these results to realistic populations of landslides shows that removing half of the total coarse sediment volume introduced by large earthquakes in the fluvial network would typically take 5 to 25 years in various tectonically active mountain belts, with little impact of earthquake magnitude and climate. Dynamic alluvial channel narrowing is therefore a key, previously unrecognized mechanism by which mountain rivers rapidly digest extreme events and maintain their capacity to incise uplifted rocks.
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Fuzzy Shannon Entropy: A Hybrid GIS-Based Landslide Susceptibility Mapping Method
Directory of Open Access Journals (Sweden)
Majid Shadman Roodposhti
2016-09-01
Full Text Available Assessing Landslide Susceptibility Mapping (LSM contributes to reducing the risk of living with landslides. Handling the vagueness associated with LSM is a challenging task. Here we show the application of hybrid GIS-based LSM. The hybrid approach embraces fuzzy membership functions (FMFs in combination with Shannon entropy, a well-known information theory-based method. Nine landslide-related criteria, along with an inventory of landslides containing 108 recent and historic landslide points, are used to prepare a susceptibility map. A random split into training (≈70% and testing (≈30% samples are used for training and validation of the LSM model. The study area—Izeh—is located in the Khuzestan province of Iran, a highly susceptible landslide zone. The performance of the hybrid method is evaluated using receiver operating characteristics (ROC curves in combination with area under the curve (AUC. The performance of the proposed hybrid method with AUC of 0.934 is superior to multi-criteria evaluation approaches using a subjective scheme in this research in comparison with a previous study using the same dataset through extended fuzzy multi-criteria evaluation with AUC value of 0.894, and was built on the basis of decision makers’ evaluation in the same study area.
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Wu, Chunhung; Huang, Jyuntai
2017-04-01
Most of the landslide cases in Taiwan were triggered by rainfall or earthquake events. The heavy rainfall in the typhoon seasons, from June to October, causes the landslide hazard more serious. Renai Towhship is of the most large landslide cases after 2009 Typhoon Morakot (from Aug. 5 to Aug. 10, 2009) in Taiwan. Around 2,744 landslides cases with the total landslide area of 21.5 km2 (landslide ratio =1.8%), including 26 large landslide cases, induced after 2009 Typhoon Morakot in Renai Towhship. The area of each large landslides case is more than 0.1 km2, and the area of the largest case is around 0.96 km2. 58% of large landslide cases locate in the area with metamorphosed sandstone. The mean slope of 26 large landslide cases ranges from 15 degree to 56 degree, and the accumulated rainfall during 2009 Typhoon Morakot ranges from 530 mm to 937 mm. Three methods, including frequency ratio method (abbreviated as FR), weights of evidence method (abbreviated as WOE), and logistic regression method (abbreviated as LR), are used in this study to establish the landslides susceptibility in the Renai Township, Nantou County, Taiwan. Eight landslide related-factors, including elevation, slope, aspect, geology, land use, distance to drainage, distance to fault, accumulation rainfall during 2009 Typhoon Morakot, are used to establish the landslide susceptibility models in this study. The landslide inventory after 2009 Typhoon Morakot is also used to test the model performance in this study. The mean accumulated rainfall in Renai Township during 2009 typhoon Morakot was around 735 mm with the maximum 1-hr, 3-hrs, and 6-hrs rainfall intensity of 44 mm/1-hr, 106 mm/3-hrs and 204 mm/6-hrs, respectively. The range of original susceptibility values established by three methods are 4.0 to 20.9 for FR, -33.8 to -16.1 for WOE, and -41.7 to 5.7 for LR, and the mean landslide susceptibility value are 8.0, -24.6 and 0.38, respectively. The AUC values are 0.815 for FR, 0.816 for WOE, and 0
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Warning Model for Shallow Landslides Induced by Extreme Rainfall
Directory of Open Access Journals (Sweden)
Lien-Kwei Chien
2015-08-01
Full Text Available In this study, the geophysical properties of the landslide-prone catchment of the Gaoping River in Taiwan were investigated using zones based on landslide history in conjunction with landslide analysis using a deterministic approach based on the TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability model. Typhoon Morakot in 2009 was selected as a simulation scenario to calibrate the combination of geophysical parameters in each zone before analyzing changes in the factor of safety (FS. Considering the amount of response time required for typhoons, suitable FS thresholds for landslide warnings are proposed for each town in the catchment area. Typhoon Fanapi of 2010 was used as a test scenario to verify the applicability of the FS as well as the efficacy of the cumulative rainfall thresholds derived in this study. Finally, the amount of response time provided by the FS thresholds in cases of yellow and red alerts was determined. All five of the landslide events reported by the Soil and Water Conservation Bureau were listed among the unstable sites identified in the proposed model, thereby demonstrating its effectiveness and accuracy in determining unstable areas and areas that require evacuation. These cumulative rainfall thresholds provide a valuable reference to guide disaster prevention authorities in the issuance of yellow and red alerts with the ability to reduce losses and save lives.
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Directory of Open Access Journals (Sweden)
Ebrahim Karimi Sangchini
2015-01-01
Full Text Available Landslides are amongst the most damaging natural hazards in mountainous regions. Every year, hundreds of people all over the world lose their lives in landslides; furthermore, there are large impacts on the local and global economy from these events. In this study, landslide hazard zonation in Babaheydar watershed using logistic regression was conducted to determine landslide hazard areas. At first, the landslide inventory map was prepared using aerial photograph interpretations and field surveys. The next step, ten landslide conditioning factors such as altitude, slope percentage, slope aspect, lithology, distance from faults, rivers, settlement and roads, land use, and precipitation were chosen as effective factors on landsliding in the study area. Subsequently, landslide susceptibility map was constructed using the logistic regression model in Geographic Information System (GIS. The ROC and Pseudo-R2 indexes were used for model assessment. Results showed that the logistic regression model provided slightly high prediction accuracy of landslide susceptibility maps in the Babaheydar Watershed with ROC equal to 0.876. Furthermore, the results revealed that about 44% of the watershed areas were located in high and very high hazard classes. The resultant landslide susceptibility maps can be useful in appropriate watershed management practices and for sustainable development in the region.
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Landslide susceptibility estimations in the Gerecse hills (Hungary).
Gerzsenyi, Dávid; Gáspár, Albert
2017-04-01
Surface movement processes are constantly posing threat to property in populated and agricultural areas in the Gerecse hills (Hungary). The affected geological formations are mainly unconsolidated sediments. Pleistocene loess and alluvial terrace sediments are overwhelmingly present, but fluvio-lacustrine sediments of the latest Miocene, and consolidated Eocene and Mesozoic limestones and marls can also be found in the area. Landslides and other surface movement processes are being studied for a long time in the area, but a comprehensive GIS-based geostatistical analysis have not yet been made for the whole area. This was the reason for choosing the Gerecse as the focus area of the study. However, the base data of our study are freely accessible from online servers, so the used method can be applied to other regions in Hungary. Qualitative data was acquired from the landslide-inventory map of the Hungarian Surface Movement Survey and from the Geological Map of Hungary (1 : 100 000). Morphometric parameters derived from the SRMT-1 DEM were used as quantitative variables. Using these parameters the distribution of elevation, slope gradient, aspect and categorized geological features were computed, both for areas affected and not affected by slope movements. Then likelihood values were computed for each parameters by comparing their distribution in the two areas. With combining the likelihood values of the four parameters relative hazard values were computed for each cell. This method is known as the "empirical probability estimation" originally published by Chung (2005). The map created this way shows each cell's place in their ranking based on the relative hazard values as a percentage for the whole study area (787 km2). These values provide information about how similar is a certain area to the areas already affected by landslides based on the four predictor variables. This map can also serve as a base for more complex landslide vulnerability studies involving
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Issues and Advances in Understanding Landslide-Generated Tsunamis: Toward a Unified Model
Geist, E. L.; Locat, J.; Lee, H. J.; Lynett, P. J.; Parsons, T.; Kayen, R. E.; Hart, P. E.
2008-12-01
The physics of tsunamis generated from submarine landslides is highly complex, involving a cross- disciplinary exchange in geophysics. In the 10 years following the devastating Papua New Guinea tsunami, there have been significant advances in understanding landslide-generated tsunamis. However, persistent issues still remain related to submarine landslide dynamics that may be addressed with collection of new marine geologic and geophysical observations. We review critical elements of landslide tsunamis in the hope of developing a unified model that encompasses all stages of the process from triggering to tsunami runup. Because the majority of non-volcanogenic landslides that generate tsunamis are triggered seismically, advances in understanding inertial displacements and changes in strength and rheologic properties in response to strong-ground motion need to be included in a unified model. For example, interaction between compliant marine sediments and multi-direction ground motion results in greater permanent plastic displacements than predicted by traditional rigid-block analysis. When considering the coupling of the overlying water layer in the generation of tsunamis, the post-failure dynamics of landslides is important since the overall rate of seafloor deformation for landslides is less than or comparable to the phase speed of tsunami waves. As such, the rheologic and mechanical behavior of the slide material needs to be well understood. For clayey and silty debris flows, a non-linear (Herschel-Bulkley) and bilinear rheology have recently been developed to explain observed runout distances and deposit thicknesses. An additional complexity to this rheology is the inclusion of hydrate-laden sediment that commonly occurs along continental slopes. Although it has been proposed in the past that gas hydrate dissociation may provide potential failure planes for slide movement, it is unclear how zones of rigid hydrate-bearing sediment surrounded by a more viscoplastic
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Short Term Patterns of Landslides Causing Death in Latin America and the Caribbean
Sepulveda, S. A.; Petley, D. N.
2015-12-01
Among natural hazards, landslides represent a significant source of loss of life in mountainous terrains. Many regions of Latin America and the Caribbean are prone to landslide activity, due to strong topographic relief, high tectonic uplift rates, seismicity and/or climate. Further, vulnerable populations are often concentrated in deep valleys or mountain foothills susceptible to catastrophic landslides, with vulnerability further increased by dense urbanization and precarious settlements in some large cities. While historic extremely catastrophic events such as the 1999 Vargas flows in Venezuela or the 1970 Huascaran rock avalanche in Peru are commonly cited to characterize landslide hazards in this region, less known is the landslide activity in periods without such large disasters. This study assesses the occurrence of fatal landslides in Latin America and the Caribbean between 2004 and 2013. Over this time period we recorded 611 landslides that caused 11,631 deaths in 25 countries, mostly as a result of rainfall triggers. The countries with the highest number of fatal landslides are Brazil, Colombia, Mexico, Guatemala, Peru and Haiti. The highest death toll for a single event was ca.3000. The dataset has not captured a strong El Niño event or large earthquakes in landslide prone areas, thus the analysis is indicative of short term rather than long term spatial and temporal patterns. Results show that at continental scale, the spatial distribution of landslides in the 2004-2013 period correlates well with relief, precipitation and population density, while the temporal distribution reflects the regional annual rainfall patterns. In urban areas, the presence of informal settlements has a big impact on the number of fatalities, while at national level weaker correlations with gross income, human development and corruption indices can be found. This work was funded by the Durham International Fellowships for Research and Enterprise and Fondecyt project 1140317.
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Is air pollution causing landslides in China?
Zhang, Ming; McSaveney, Mauri J.
2018-01-01
Air pollution in China often exceeds "unhealthy" levels, but Chinese air is not only a threat from being breathed: the pollutants may also be causing fatal landslides. Very acid rain from severe air pollution falls widely in southwest China, where coal is a major energy source. We discuss where acid rain may provide an unsuspected link between mining and the fatal 2009 Jiweishan landslide in southwest China; it may have reduced the strength of a thin, calcareous, black sapropelic shale in Jiweishan Mountain by removing cementing carbonate minerals and sapropel matrix. Mining beneath the potential slide mass may not have directly triggered the landslide, but collapse of abandoned adits drained a perched aquifer above a regional black-shale aquiclude. Inflow of acid, oxygenated water and nutrients into the aquiclude may have accelerated the reduction of strength of the weakest rocks and consequently led to rapid sliding of a large rock mass on a layer of weathered shale left composed largely of soft, and slippery talc.
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High-throughput landslide modelling using computational grids
Wallace, M.; Metson, S.; Holcombe, L.; Anderson, M.; Newbold, D.; Brook, N.
2012-04-01
Landslides are an increasing problem in developing countries. Multiple landslides can be triggered by heavy rainfall resulting in loss of life, homes and critical infrastructure. Through computer simulation of individual slopes it is possible to predict the causes, timing and magnitude of landslides and estimate the potential physical impact. Geographical scientists at the University of Bristol have developed software that integrates a physically-based slope hydrology and stability model (CHASM) with an econometric model (QUESTA) in order to predict landslide risk over time. These models allow multiple scenarios to be evaluated for each slope, accounting for data uncertainties, different engineering interventions, risk management approaches and rainfall patterns. Individual scenarios can be computationally intensive, however each scenario is independent and so multiple scenarios can be executed in parallel. As more simulations are carried out the overhead involved in managing input and output data becomes significant. This is a greater problem if multiple slopes are considered concurrently, as is required both for landslide research and for effective disaster planning at national levels. There are two critical factors in this context: generated data volumes can be in the order of tens of terabytes, and greater numbers of simulations result in long total runtimes. Users of such models, in both the research community and in developing countries, need to develop a means for handling the generation and submission of landside modelling experiments, and the storage and analysis of the resulting datasets. Additionally, governments in developing countries typically lack the necessary computing resources and infrastructure. Consequently, knowledge that could be gained by aggregating simulation results from many different scenarios across many different slopes remains hidden within the data. To address these data and workload management issues, University of Bristol particle
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Effect of landslides on the structural characteristics of land-cover based on complex networks
He, Jing; Tang, Chuan; Liu, Gang; Li, Weile
2017-09-01
Landslides have been widely studied by geologists. However, previous studies mainly focused on the formation of landslides and never considered the effect of landslides on the structural characteristics of land-cover. Here we define the modeling of the graph topology for the land-cover, using the satellite images of the earth’s surface before and after the earthquake. We find that the land-cover network satisfies the power-law distribution, whether the land-cover contains landslides or not. However, landslides may change some parameters or measures of the structural characteristics of land-cover. The results show that the linear coefficient, modularity and area distribution are all changed after the occurence of landslides, which means the structural characteristics of the land-cover are changed.
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Barclay, R. S.; Soul, L.; Bolton, A.; Wilson, J. P.; Megonigal, P.; Wing, S. L.
2017-12-01
During the Late Cretaceous and Paleogene, the Earth's climate was much warmer than today, often punctuated by rapid hyperthermal events. The background warmth and hyperthermals are often attributed to increased atmospheric carbon dioxide (pCO2), yet paleo-pCO2 proxy estimates for this interval often disagree widely, and there are few paired records of temperature and pCO2. Consequently, we have an inadequate understanding of what generated past warm climates, and of the magnitude of pCO2 change associated with hyperthermals. We aim to develop a more reliable stomatal proxy for paleo-pCO2 by quantifying the effect of pCO2 and other environmental variables on stomatal properties of living Ginkgo biloba trees. Herbarium collections of G. biloba demonstrate that the stomatal index proxy for paleo-pCO2 is strongly correlated with pCO2 over the range of 290-400 ppm. However, despite wide application of the Ginkgo paleo-pCO2 barometer, our understanding of pCO2 in the fossil record has been hindered because the morphological and physiological changes in Ginkgo biloba stomata under pCO2 above 400 ppm have been poorly constrained. To address this problem, we are conducting an elevated CO2 experiment that will quantify the response of Ginkgo to elevated pCO2, an experiment we call 'Fossil Atmospheres'. We are growing 15 Ginkgo biloba trees in open-topped chambers in natural field conditions, under atmospheres with ambient (400), 600, 800, and 1,000 ppm of CO2. Each tree is regularly monitored for changes in stomatal frequency, and rates of photosynthesis and transpiration to constrain parameters used in gas exchange models of paleo-pCO2. We have also involved citizen scientists in the process of collecting stomatal index measurements with the Zooniverse platform, utilizing the interaction to educate citizens about modern climate change from the less-menacing viewpoint of deep-time climate change events. Our results can then be used to infer paleo-pCO2 from stomatal features
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Characteristic of selected frequency luminescence for paleo-debris flow deposits in Jiangjia valley
International Nuclear Information System (INIS)
Liu Zhaowen; Wei Mingjian; Pan Baolin; Liu Chao; Li Dongxu
2008-01-01
Eight paleo-debris flow samples from Nideping, Duozhao, Dawazi valley, and Jiangjia valley in Yunnan Province were tested with BG2003 luminescence spectrograph. The characteristic spectra of the selected frequency luminescence of paleo-debris flow deposits from the different locations were obtained. Excited at 488 nm, the wavelengths of emission photons from all samples are 300, 310, 320, 400 and 460 nm. With green excitation (532 nm), the wavelengths of emission photons from all samples are 300, 310, 320 and 460 nm. Then it is determined that the luminescence spectrographs of Nideping are almost same in different time, however, they are different in Dawazi valley and Duozhao. Taking Nideping for example, excited at green, the debris flow substances from the upper, middle, or lower zone of this platform. Response to increasing irradiation dose at 310, 320, and 460 nm, we can define the wavelengths used for dating. (authors)
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Probabilistic landslide hazards and risk mapping on Penang Island ...
Indian Academy of Sciences (India)
This paper deals with landslide hazards and risk analysis of Penang Island, Malaysia using Geo- .... require a priori knowledge of the main causes of landslides .... Soil. Rengam-bukit. 289450. 10.03. 96. 20.73. 2.07 temiang association. Selangor-kangkong. 34197. 1.18. 0. 0.00. 0.00 association. Local alluvium-. 373655.
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Characterization of groundwater dynamics in landslides in varved clays
Van der Spek, J.E.; Bogaard, T.A.; Bakker, M.
2013-01-01
Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trièves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and
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Experiences from coordinated national-level landslide and flood forecasting in Norway
Krøgli, Ingeborg; Fleig, Anne; Glad, Per; Dahl, Mads-Peter; Devoli, Graziella; Colleuille, Hervé
2015-04-01
While flood forecasting at national level is quite well established and operational in many countries worldwide, landslide forecasting at national level is still seldom. Examples of coordinated flood and landslide forecasting are even rarer. Most of the time flood and landslide forecasters work separately (investigating, defining thresholds, and developing models) and most of the time without communication with each other. One example of coordinated operational early warning systems (EWS) for flooding and shallow landslides is found at the Norwegian Water Resources and Energy Directorate (NVE) in Norway. In this presentation we give an introduction to the two separate but tightly collaborative EWSs and to the coordination of these. The two EWSs are being operated from the same office, every day using similar hydro-meteorological prognosis and hydrological models. Prognosis and model outputs on e.g. discharge, snow melt, soil water content and exceeded landslide thresholds are evaluated in a web based decision-making tool (xgeo.no). The experts performing forecasts are hydrologists, geologists and physical geographers. A similar warning scale, based on colors (green, yellow, orange and red) is used for both EWSs, however thresholds for flood and landslide warning levels are defined differently. Also warning areas may not necessary be the same for both hazards and depending on the specific meteorological event, duration of the warning periods can differ. We present how knowledge, models and tools, but also human and economic resources are being shared between the two EWSs. Moreover, we discuss challenges faced in the communication of warning messages using recent flood and landslide events as examples.
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A rapid extraction of landslide disaster information research based on GF-1 image
Wang, Sai; Xu, Suning; Peng, Ling; Wang, Zhiyi; Wang, Na
2015-08-01
In recent years, the landslide disasters occurred frequently because of the seismic activity. It brings great harm to people's life. It has caused high attention of the state and the extensive concern of society. In the field of geological disaster, landslide information extraction based on remote sensing has been controversial, but high resolution remote sensing image can improve the accuracy of information extraction effectively with its rich texture and geometry information. Therefore, it is feasible to extract the information of earthquake- triggered landslides with serious surface damage and large scale. Taking the Wenchuan county as the study area, this paper uses multi-scale segmentation method to extract the landslide image object through domestic GF-1 images and DEM data, which uses the estimation of scale parameter tool to determine the optimal segmentation scale; After analyzing the characteristics of landslide high-resolution image comprehensively and selecting spectrum feature, texture feature, geometric features and landform characteristics of the image, we can establish the extracting rules to extract landslide disaster information. The extraction results show that there are 20 landslide whose total area is 521279.31 .Compared with visual interpretation results, the extraction accuracy is 72.22%. This study indicates its efficient and feasible to extract earthquake landslide disaster information based on high resolution remote sensing and it provides important technical support for post-disaster emergency investigation and disaster assessment.
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Statistical characteristics and stability index (si) of large-sized landslide dams around the world
International Nuclear Information System (INIS)
Iqbal, J.; Dai, F.; Raja, I.A.
2014-01-01
In the last few decades, landslide dams have received greater attention of researchers, as they have caused loss to property and human lives. Over 261 large-sized landslide dams from different countries of the world with volume greater than 1 x 105 m have been reviewed for this study. The data collected for this study shows that 58% of the catastrophic landslides were triggered by earthquakes and 21 % by rainfall, revealing that earthquake and rainfall are the two major triggers, accounting for 75% of large-sized landslide dams. These land-slides were most frequent during last two decades (1990-2010) throughout the world. The mean landslide dam volume of the studied cases was 53.39 x 10 m with mean dam height of 71.98 m, while the mean lake volume was found to be 156.62 x 10 m. Failure of these large landslide dams pose a severe threat to the property and people living downstream, hence immediate attention is required to deal with this problem. A stability index (SI) has been derived on the basis on 59 large-sized landslide dams (out of the 261 dams) with complete parametric information. (author)
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Heyerdahl, Håkon; Høydal, Øyvind
2016-04-01
The Gudbrandsdalen valley in Eastern Norway lies in a region where annual precipitation is generally low (down to 300 mm/year). The landslide activity has consequently historically been low, although the lower part of the valley sides generally is draped with thick layers of Quaternary deposits, primarily of glacial or glaciofluvial origin. The perception of natural hazards in the valley was previously primarily connected to flooding in the main river in the valley bottom during early summer, due to large discharges resulting from snowmelt in the mountainous regions west and east of the valley. However, several high-intensity events have changed the image of the region. Starting with a localized, but intense, landslide event in the Northern part of the valley in year 2008, two larger events covering almost the entire valley occurred in the years 2011 and 2013. A high number of landslides was triggered in all these events, including many flash floods and debris flows/debris slides in small and steep tributary rivers along the valley slopes. Landslide triggering covers different release mechanisms: In 2008, landslides were triggered without precipitation in not-frozen soil deposits without snow cover in the lower part of the valley. Groundwater flow through the permeable bedrock ("Otta schist") resulting from snow-melt in the elevated mountainous areas caused landslide triggering due to positive pore-water pressures forming at the bedrock surface below soil deposits, or at depressions in the terrain. Subsequent rainfall resulted in even more landslides being released. In later events (years 2011 and 2013) many landslides were caused by surface water taking new paths downslope, often due to man-made changes in existing waterways (typically poorly planned drainage solutions or new roads). Relatively small discharges in slopes with unconsolidated and easily erodible glacial deposits (typically lateral moraine) in many cases lead to small initial slides that down
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Changing pattern of landslide risk in Europe - The SafeLand project
Nadim, F.; Kalsnes, B.
2012-04-01
The need to protect people and property with a changing pattern of landslide hazard and risk caused by climate change and changes in demography, and the reality for societies in Europe to live with the risk associated with natural hazards, were the motives for the project SafeLand: "Living with landslide risk in Europe: Assessment, effects of global change, and risk management strategies." SafeLand is a large, integrating research project under the European Commission's 7th Framework Programme (FP7). The project started on 1 May 2009 and will end on 30 April 2012. It involves 27 partners from 12 European countries, and has international collaborators and advisers from China, India, USA, Japan and Hong Kong. SafeLand also involves 25 End-Users from 11 countries. SafeLand is coordinated by the International Centre for Geohazards (ICG) at Norwegian Geotechnical Institute in Norway. Further information on the SafeLand project can be found at its web site http://safeland-fp7.eu/. Main results achieved in SafeLand include: - Various guidelines related to landslide triggering processes and run-out modelling. - Development and testing of several empirical methods for predicting the characteristics of threshold rainfall events for triggering of precipitation-induced landslides, and development of an empirical model for assessing the changes in landslide frequency (hazard) as a function of changes in the demography and population density. - Guideline for landslide susceptibility, hazard and risk assessment and zoning. - New methodologies for physical and societal vulnerability assessment. - Identification of landslide hazard and risk hotspots for Europe. The results show clearly where areas with the largest landslide risk are located in Europe and the objective approach allows a ranking of the countries by exposed area and population. - Different regional and local climate model simulations over selected regions of Europe at spatial resolutions of 10x10 km and 2.8x2.8 km
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Directory of Open Access Journals (Sweden)
Suhua Zhou
2016-04-01
Full Text Available The development of landslide susceptibility maps is of great importance due to rapid urbanization. The purpose of this study is to present a method to integrate the subjective weight with objective weight for regional landslide susceptibility mapping on the geographical information system (GIS platform. The analytical hierarchy process (AHP, which is subjective, was employed to weight predictive factors’ contribution to landslide occurrence. The frequency ratio (FR method, which is objective, was used to derive subclasses’ frequency ratio with respect to landslides that indicate the relative importance of a subclass within each predictive factor. A case study was carried out at Tsushima Island, Japan, using a historical inventory of 534 landslides and seven predictive factors: elevation, slope, aspect, terrain roughness index (TRI, lithology, land cover and mean annual precipitation (MAP. The landslide susceptibility index (LSI was calculated using the weighted linear combination of factors’ weights and subclasses’ weights. The study area was classified into five susceptibility zones according to the LSI. In addition, the produced susceptibility map was compared with maps generated using the conventional FR and AHP method and validated using the relative landslide index (RLI. The validation result showed that the proposed method performed better than the conventional application of the FR method and AHP method. The obtained landslide susceptibility maps could serve as a scientific basis for urban planning and landslide hazard management.
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Landslide susceptibility mapping on a global scale using the method of logistic regression
Directory of Open Access Journals (Sweden)
L. Lin
2017-08-01
Full Text Available This paper proposes a statistical model for mapping global landslide susceptibility based on logistic regression. After investigating explanatory factors for landslides in the existing literature, five factors were selected for model landslide susceptibility: relative relief, extreme precipitation, lithology, ground motion and soil moisture. When building the model, 70 % of landslide and nonlandslide points were randomly selected for logistic regression, and the others were used for model validation. To evaluate the accuracy of predictive models, this paper adopts several criteria including a receiver operating characteristic (ROC curve method. Logistic regression experiments found all five factors to be significant in explaining landslide occurrence on a global scale. During the modeling process, percentage correct in confusion matrix of landslide classification was approximately 80 % and the area under the curve (AUC was nearly 0.87. During the validation process, the above statistics were about 81 % and 0.88, respectively. Such a result indicates that the model has strong robustness and stable performance. This model found that at a global scale, soil moisture can be dominant in the occurrence of landslides and topographic factor may be secondary.
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Uncertainty evaluation of a regional real-time system for rain-induced landslides
Kirschbaum, Dalia; Stanley, Thomas; Yatheendradas, Soni
2015-04-01
A new prototype regional model and evaluation framework has been developed over Central America and the Caribbean region using satellite-based information including precipitation estimates, modeled soil moisture, topography, soils, as well as regionally available datasets such as road networks and distance to fault zones. The algorithm framework incorporates three static variables: a susceptibility map; a 24-hr rainfall triggering threshold; and an antecedent soil moisture variable threshold, which have been calibrated using historic landslide events. The thresholds are regionally heterogeneous and are based on the percentile distribution of the rainfall or antecedent moisture time series. A simple decision tree algorithm framework integrates all three variables with the rainfall and soil moisture time series and generates a landslide nowcast in real-time based on the previous 24 hours over this region. This system has been evaluated using several available landslide inventories over the Central America and Caribbean region. Spatiotemporal uncertainty and evaluation metrics of the model are presented here based on available landslides reports. This work also presents a probabilistic representation of potential landslide activity over the region which can be used to further refine and improve the real-time landslide hazard assessment system as well as better identify and characterize the uncertainties inherent in this type of regional approach. The landslide algorithm provides a flexible framework to improve hazard estimation and reduce uncertainty at any spatial and temporal scale.
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Hong, Yang; Adler, Robert F.; Huffman, George J.
2007-01-01
Landslides are one of the most widespread natural hazards on Earth, responsible for thousands of deaths and billions of dollars in property damage every year. In the U.S. alone landslides occur in every state, causing an estimated $2 billion in damage and 25- 50 deaths each year. Annual average loss of life from landslide hazards in Japan is 170. The situation is much worse in developing countries and remote mountainous regions due to lack of financial resources and inadequate disaster management ability. Recently, a landslide buried an entire village on the Philippines Island of Leyte on Feb 17,2006, with at least 1800 reported deaths and only 3 houses left standing of the original 300. Intense storms with high-intensity , long-duration rainfall have great potential to trigger rapidly moving landslides, resulting in casualties and property damage across the world. In recent years, through the availability of remotely sensed datasets, it has become possible to conduct global-scale landslide hazard assessment. This paper evaluates the potential of the real-time NASA TRMM-based Multi-satellite Precipitation Analysis (TMPA) system to advance our understanding of and predictive ability for rainfall-triggered landslides. Early results show that the landslide occurrences are closely associated with the spatial patterns and temporal distribution of rainfall characteristics. Particularly, the number of landslide occurrences and the relative importance of rainfall in triggering landslides rely on the influence of rainfall attributes [e.g. rainfall climatology, antecedent rainfall accumulation, and intensity-duration of rainstorms). TMPA precipitation data are available in both real-time and post-real-time versions, which are useful to assess the location and timing of rainfall-triggered landslide hazards by monitoring landslide-prone areas while receiving heavy rainfall. For the purpose of identifying rainfall-triggered landslides, an empirical global rainfall intensity
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Landslide: Systematic Dynamic Race Detection in Kernel Space
2012-05-01
schedule_in_flight← true; CAUSE_TIMER_INTERRUPT(); end if end function Thread Scheduling Finally, the Landslide scheduler is responsible for managing ...child process vanish() simultaneously. • double_wait: Tests interactions of multiple waiters on a single child. • double_thread_fork: Tests for...conditions using Landslide. We describe them here. • Too many waiters allowed. Using the double_wait test case, Group 1 found a bug in which more threads
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Eker, Remzi; Aydın, Abdurrahim; Hübl, Johannes
2017-12-19
In the present study, UAV-based monitoring of the Gallenzerkogel landslide (Ybbs, Lower Austria) was carried out by three flight missions. High-resolution digital elevation models (DEMs), orthophotos, and density point clouds were generated from UAV-based aerial photos via structure-from-motion (SfM). According to ground control points (GCPs), an average of 4 cm root mean square error (RMSE) was found for all models. In addition, light detection and ranging (LIDAR) data from 2009, representing the prefailure topography, was utilized as a digital terrain model (DTM) and digital surface model (DSM). First, the DEM of difference (DoD) between the first UAV flight data and the LIDAR-DTM was determined and according to the generated DoD deformation map, an elevation difference of between - 6.6 and 2 m was found. Over the landslide area, a total of 4380.1 m 3 of slope material had been eroded, while 297.4 m 3 of the material had accumulated within the most active part of the slope. In addition, 688.3 m 3 of the total eroded material had belonged to the road destroyed by the landslide. Because of the vegetation surrounding the landslide area, the Multiscale Model-to-Model Cloud Comparison (M3C2) algorithm was then applied to compare the first and second UAV flight data. After eliminating both the distance uncertainty values of higher than 15 cm and the nonsignificant changes, the M3C2 distance obtained was between - 2.5 and 2.5 m. Moreover, the high-resolution orthophoto generated by the third flight allowed visual monitoring of the ongoing control/stabilization work in the area.
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Combining heuristic and statistical techniques in landslide hazard assessments
Cepeda, Jose; Schwendtner, Barbara; Quan, Byron; Nadim, Farrokh; Diaz, Manuel; Molina, Giovanni
2014-05-01
As a contribution to the Global Assessment Report 2013 - GAR2013, coordinated by the United Nations International Strategy for Disaster Reduction - UNISDR, a drill-down exercise for landslide hazard assessment was carried out by entering the results of both heuristic and statistical techniques into a new but simple combination rule. The data available for this evaluation included landslide inventories, both historical and event-based. In addition to the application of a heuristic method used in the previous editions of GAR, the availability of inventories motivated the use of statistical methods. The heuristic technique is largely based on the Mora & Vahrson method, which estimates hazard as the product of susceptibility and triggering factors, where classes are weighted based on expert judgment and experience. Two statistical methods were also applied: the landslide index method, which estimates weights of the classes for the susceptibility and triggering factors based on the evidence provided by the density of landslides in each class of the factors; and the weights of evidence method, which extends the previous technique to include both positive and negative evidence of landslide occurrence in the estimation of weights for the classes. One key aspect during the hazard evaluation was the decision on the methodology to be chosen for the final assessment. Instead of opting for a single methodology, it was decided to combine the results of the three implemented techniques using a combination rule based on a normalization of the results of each method. The hazard evaluation was performed for both earthquake- and rainfall-induced landslides. The country chosen for the drill-down exercise was El Salvador. The results indicate that highest hazard levels are concentrated along the central volcanic chain and at the centre of the northern mountains.
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Landslide Hazard Analysis with Multidisciplinary Approach: İstanbul example
Kılıç, Osman; Baş, Mahmut; Yahya Menteşe, Emin; Tarih, Ahmet; Duran, Kemal; Gümüş, Salim; Rıza Yapar, Evrens; Emin Karasu, Muhammed; Acar Kara, Sema; Karaman, Abdullah; Özalaybey, Serdar; Zor, Ekrem; Ediger, Vedat; Arpat, Esen; Özgül, Necdet; Polat, Feyzi; Doǧan, Uǧur; Çakır, Ziyadin
2017-04-01
There are several methods that can be utilized for describing the landslide mechanisms. While some of them are commonly used, there are relatively new methods that have been proven to be useful. Obviously, each method has its own limitations and thus integrated use of these methods contributes to obtaining a realistic landslide model. The slopes of Küçükçekmece and Büyükçekmece Lagoons located at the Marmara Sea coast of İstanbul, Turkey, are among most specific examples of complex type landslides. The landslides in the area started developing at low sea level, and appears to ceased or at least slowed down to be at minimum after the sea level rise, as oppose to the still-active landslides that continue to cause damage especially in the valley slopes above the recent sea level between the two lagoons. To clarify the characteristics of these slope movements and classify them in most accurate way, Directorate of Earthquake and Ground Research of Istanbul Metropolitan Municipality launched a project in cooperation with Marmara Research Center of The Scientific and Technological Research Council of Turkey (TÜBİTAK). The project benefits the utility of the techniques of different disciplines such as geology, geophysics, geomorphology, hydrogeology, geotechnics, geodesy, remote sensing and meteorology. The observations include detailed mapping of topography by airborne LIDAR, deformation monitoring with more than 80 GPS stations, Ground Based Synthetic Aperture Radar measurements in 8 critical zones, 81 geological drills and more than 20 km of geophysical measurements. With three years of monitoring, the acquired data, and the results such as landslide hazard map, were integrated in GIS database for the purpose of easing tasks for the urban planners and the decision makers.
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Directory of Open Access Journals (Sweden)
I. Baroň
2013-10-01
Full Text Available Airborne geophysics is a promising method for investigating landslides. Here we present a case study of multisensor airborne geophysical survey at the catastrophic landslide Stože near Log pod Mangrtom in Slovenia, which was conducted in the framework of the European FP7th Project "SafeLand". Based on the survey itself and achieved results, we discuss applicability, limits, and benefits and costs of the method for investigating landslides in steep alpine terrains. Despite of several operational constraints, the airborne electromagnetic survey of the area well presented the lithological pattern and water saturation. The high resistivity regions mostly indicated drained slope scree and landslide mass, drained and loosened material of the moraine deposit in the tension zone of the landslide with present cracks and cavities. The minima of the resistivity pattern were attributed to the outcrop of marls rich in clay, to water-saturated moraine deposit above impermeable marls in the tension zone, and to water-saturated porous alluvial gravel and landslide scree along the Koritnica River. The magnetic survey proved to be inapplicable for such a small and rough area. The Potassium and Thorium maps, on the other hand, both well identified the regions of tension inside the landslide zone, outcrops of marls and dolomite, clay-rich colluvium, weathered zones along a regional tectonic fault, and alluvial deposits and deposits of debris flows, and the minima of the 137Cs clearly revealed the zones of material removal due to recent mass movements.
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Tracer techniques in landslide area surveys
Energy Technology Data Exchange (ETDEWEB)
Turcek, P [Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia)
1982-10-01
One of the most important effects leading to slope movements is the action of surface and ground water on rocks. The rock movement usually occurs as a result of dilatation. The increased rock porosity in the area of the slide zone leads to higher permeability. The measurement of the ground water flow rate by the single borehole method using the /sup 131/I radiotracer in objects with perforated casings, installed in the landslide zone, can be used to locate sliding surfaces. The method was successfully applied in landslides at Miksova, Turany, Liskova and Podhradi where drainage measures were taken, the efficiency of which can be checked periodically.
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Predictive susceptibility analysis of typhoon induced landslides in Central Taiwan
Shou, Keh-Jian; Lin, Zora
2017-04-01
Climate change caused by global warming affects Taiwan significantly for the past decade. The increasing frequency of extreme rainfall events, in which concentrated and intensive rainfalls generally cause geohazards including landslides and debris flows. The extraordinary, such as 2004 Mindulle and 2009 Morakot, hit Taiwan and induced serious flooding and landslides. This study employs rainfall frequency analysis together with the atmospheric general circulation model (AGCM) downscaling estimation to understand the temporal rainfall trends, distributions, and intensities in the adopted Wu River watershed in Central Taiwan. To assess the spatial hazard of the landslides, landslide susceptibility analysis was also applied. Different types of rainfall factors were tested in the susceptibility models for a better accuracy. In addition, the routes of typhoons were also considered in the predictive analysis. The results of predictive analysis can be applied for risk prevention and management in the study area.
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Social Geology and Landslide Disaster Risk Reduction in Sri Lanka
Directory of Open Access Journals (Sweden)
Jayasingha P
2017-03-01
Full Text Available AbstractLandslide disaster risk reduction is presently a challenging task facing by Sri Lankangeologists. Increasing trend of population growth in Sri Lanka has adversely affected thestability of central highland due to various human activities. Among them establishment ofhuman settlements and change in land use pattern have become a serious issue in triggeringland instabilities in central highland of the country. National Building Research Oragnisationwhich is the main focal point in land slide disaster risk reduction in Sri Lanka has takenvaluable and timely needed actions including preparation of landslide hazard zonation maps,early warnings and mitigations. Though the landslide is a geological phenomenon, it is highlyinteracted with human societies. Hence managing the issues arising with the landslideoccurrence should be addressed with a sociological approach. This new approach is known asSocio Geological approach which is discussed here.Key words: Landslide, Geology, Socio Geology, Social Geologist
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Combining TerraSAR-X and SPOT-5 data for object-based landslide detection
Friedl, B.; Hölbling, D.; Füreder, P.
2012-04-01
Landslide detection and classification is an essential requirement in pre- and post-disaster hazard analysis. In earlier studies landslide detection often was achieved through time-consuming and cost-intensive field surveys and visual orthophoto interpretation. Recent studies show that Earth Observation (EO) data offer new opportunities for fast, reliable and accurate landslide detection and classification, which may conduce to an effective landslide monitoring and landslide hazard management. To ensure the fast recognition and classification of landslides at a regional scale, a (semi-)automated object-based landslide detection approach is established for a study site situated in the Huaguoshan catchment, Southern Taiwan. The study site exhibits a high vulnerability to landslides and debris flows, which are predominantly typhoon-induced. Through the integration of optical satellite data (SPOT-5 with 2.5 m GSD), SAR (Synthetic Aperture Radar) data (TerraSAR-X Spotlight with 2.95 m GSD) and digital elevation information (DEM with 5 m GSD) including its derived products (e.g. slope, curvature, flow accumulation) landslides may be examined in a more efficient way as if relying on single data sources only. The combination of optical and SAR data in an object-based image analysis (OBIA) domain for landslide detection and classification has not been investigated so far, even if SAR imagery show valuable properties for landslide detection, which differ from optical data (e.g. high sensitivity to surface roughness and soil moisture). The main purpose of this study is to recognize and analyze existing landslides by applying object-based image analysis making use of eCognition software. OBIA provides a framework for examining features defined by spectral, spatial, textural, contextual as well as hierarchical properties. Objects are derived through image segmentation and serve as input for the classification process, which relies on transparent rulesets, representing knowledge
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Directory of Open Access Journals (Sweden)
C. Y. Wu
2013-09-01
Full Text Available Landslide spatial, temporal, and size probabilities were used to perform a landslide hazard assessment in this study. Eleven intrinsic geomorphological, and two extrinsic rainfall factors were evaluated as landslide susceptibility related factors as they related to the success rate curves, landslide ratio plots, frequency distributions of landslide and non-landslide groups, as well as probability–probability plots. Data on landslides caused by Typhoon Aere in the Shihmen watershed were selected to train the susceptibility model. The landslide area probability, based on the power law relationship between the landslide area and a noncumulative number, was analyzed using the Pearson type 5 probability density function. The exceedance probabilities of rainfall with various recurrence intervals, including 2, 5, 10, 20, 50, 100 and 200 yr, were used to determine the temporal probabilities of the events. The study was conducted in the Shihmen watershed, which has an area of 760 km2 and is one of the main water sources for northern Taiwan. The validation result of Typhoon Krosa demonstrated that this landslide hazard model could be used to predict the landslide probabilities. The results suggested that integration of spatial, area, and exceedance probabilities to estimate the annual probability of each slope unit is feasible. The advantage of this annual landslide probability model lies in its ability to estimate the annual landslide risk, instead of a scenario-based risk.
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Directory of Open Access Journals (Sweden)
Daniel Hölbling
2016-11-01
Full Text Available Accurate mapping of landslides and the reliable identification of areas most affected by landslides are essential for advancing the understanding of landslide erosion processes. Remote sensing data provides a valuable source of information on the spatial distribution and location of landslides. In this paper we present an approach for identifying landslide-prone “hotspots” and their spatio-temporal variability by analyzing historical and recent aerial photography from five different dates, ranging from 1944 to 2011, for a study site near the town of Pahiatua, southeastern North Island, New Zealand. Landslide hotspots are identified from the distribution of semi-automatically detected landslides using object-based image analysis (OBIA, and compared to hotspots derived from manually mapped landslides. When comparing the overlapping areas of the semi-automatically and manually mapped landslides the accuracy values of the OBIA results range between 46% and 61% for the producer’s accuracy and between 44% and 77% for the user’s accuracy. When evaluating whether a manually digitized landslide polygon is only intersected to some extent by any semi-automatically mapped landslide, we observe that for the natural-color images the landslide detection rate is 83% for 2011 and 93% for 2005; for the panchromatic images the values are slightly lower (67% for 1997, 74% for 1979, and 72% for 1944. A comparison of the derived landslide hotspot maps shows that the distribution of the manually identified landslides and those mapped with OBIA is very similar for all periods; though the results also reveal that mapping landslide tails generally requires visual interpretation. Information on the spatio-temporal evolution of landslide hotspots can be useful for the development of location-specific, beneficial intervention measures and for assessing landscape dynamics.
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Bird Perches Increase Forest Seeds on Puerto Rican Landslides.
Aaron B. Shiels; Lawrence R. Walker
2003-01-01
Landslides result in the loss of vertical vegetative structure, soil nutrients, and the soil seed bank. These losses impede timely recovery of tropical forest communities. In this study we added bird perches to six Puerto Rican landslides with three types of surfaces (bare, climbing fern, grass) in an effort to facilitate inputs of forest seeds through bird dispersal...
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Morphometry and kinematics of landslides inferred from precise DTMs in West Belgium
Directory of Open Access Journals (Sweden)
O. Dewitte
2005-01-01
Full Text Available The Flemish Ardennes (W Belgium are known to be affected by deep-seated landslides. The assessment of the landslide reactivation hazard requires understanding the driving processes and delimiting precisely not only the landslide boundaries but especially that of their most active parts. Precise 3D models of 13 landslides were produced by digital stereophotogrammetry using aerial photographs of different dates. Dealing with photographs at the scale 1:25000 or larger, we obtained for each model an accuracy better than 0.5m. As a first result, the main size parameters of the landslides (width, length, depth, volume, ... are easily computed. Moreover, the obtained DTMs may be subtracted from each other in order to determine the apparent vertical displacement of each pixel during the interval of time considered. Provided that more than 2 epochs are documented, such DTMs not only supply precise information about distribution and style of the landslide activity but may also point to temporal variations in this activity. The subtraction of DTMs allows us to give an estimation of the volume of the 'uplifted' and 'collapsed' terrains between two epochs.
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Chen, C. Y.; Willett, S.; West, A. J.; Dadson, S. J.; Hovius, N.; Christl, M.; Shyu, J. B. H.
2017-12-01
The southern Central Range of Taiwan is located at a tectonic transition zone between an oceanic subduction zone and the arc-continent collision forming the Taiwan orogen. The rapidly evolving tectonic setting, tropical climate and frequent typhoons result in a complex uplift pattern, transient landscapes and extensive landslides. For this study, we obtained a series of 10Be concentrations over the last decade for 13 major drainage basins in the southern Central Range, bracketing the occurrence of a major typhoon, Morakot, which hit Taiwan in 2009 and triggered thousands of landslides. This time series allows us to simultaneously estimate the background erosion rate and assess the impact of Morakot-triggered landslides on 10Be concentrations. The time series of 10Be concentrations shows temporally lower concentrations of 10Be indicating dilution following the Morakot event in most basins. The diluted 10Be concentrations imply erosion rates up to three times higher than the lowest measured rates in the same basins. We constructed a simple sediment-mixing model parameterized by a sudden input of sediment supplied from landslides superimposed on a background denudation rate. This model was calibrated to measured landslide inventories and the series of 10Be data. We obtain a range of permissible background erosion rate and fraction of landslide sediments over time for each basin. The inferred background erosion rate reveals a northward increasing trend, reflecting the initial stage of the mountain building and indicating tectonic forcing is the main driver of the landscape evolution in the southern Central Range. The temporal changes in fraction of landslide sediments show that the available landslide material generated by the Morakot event is decreasing over time with a timescale of several years.
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Paleo-channel deposition of natural uranium at a US Air Force landfill
International Nuclear Information System (INIS)
Young, Carl; Weismann, Joseph; Caputo, Daniel
2007-01-01
Available in abstract form only. Full text of publication follows: The US Air Force sought to identify the source of radionuclides that were detected in groundwater surrounding a closed solid waste landfill at the former Lowry Air Force Base in Denver, Colorado, USA. Gross alpha, gross beta, and uranium levels in groundwater were thought to exceed US drinking water standards and down-gradient concentrations exceeded up-gradient concentrations. Our study has concluded that the elevated radionuclide concentrations are due to naturally-occurring uranium in the regional watershed and that the uranium is being released from paleo-channel sediments beneath the site. Groundwater samples were collected from monitor wells, surface water and sediments over four consecutive quarters. A list of 23 radionuclides was developed for analysis based on historical landfill records. Concentrations of major ions and metals and standard geochemical parameters were analyzed. The only radionuclide found to be above regulatory standards was uranium. A search of regional records shows that uranium is abundant in the upstream drainage basin. Analysis of uranium isotopic ratios shows that the uranium has not been processed for enrichment nor is it depleted uranium. There is however slight enrichment in the U-234:U- 238 activity ratio, which is consistent with uranium that has undergone aqueous transport. Comparison of up-gradient versus down-gradient uranium concentrations in groundwater confirms that higher uranium concentrations are found in the down-gradient wells. The US drinking water standard of 30 μg/L for uranium was exceeded in some of the up-gradient wells and in most of the down-gradient wells. Several lines of evidence indicate that natural uranium occurring in streams has been preferentially deposited in paleo-channel sediments beneath the site, and that the paleo-channel deposits are causing the increased uranium concentrations in down-gradient groundwater compared to up
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Neural Network-Based Model for Landslide Susceptibility and Soil Longitudinal Profile Analyses
DEFF Research Database (Denmark)
Farrokhzad, F.; Barari, Amin; Choobbasti, A. J.
2011-01-01
The purpose of this study was to create an empirical model for assessing the landslide risk potential at Savadkouh Azad University, which is located in the rural surroundings of Savadkouh, about 5 km from the city of Pol-Sefid in northern Iran. The soil longitudinal profile of the city of Babol......, located 25 km from the Caspian Sea, also was predicted with an artificial neural network (ANN). A multilayer perceptron neural network model was applied to the landslide area and was used to analyze specific elements in the study area that contributed to previous landsliding events. The ANN models were...... studies in landslide susceptibility zonation....
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Pradhan, Biswajeet; Lee, Saro; Buchroithner, Manfred
Landslides are the most common natural hazards in Malaysia. Preparation of landslide suscep-tibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of landslides, producing a reliable susceptibility map is not easy. In this study, a new attempt is tried to produce landslide susceptibility map of a part of Cameron Valley of Malaysia. This paper develops an adaptive neuro-fuzzy inference system (ANFIS) based on a geographic information system (GIS) environment for landslide susceptibility mapping. To ob-tain the neuro-fuzzy relations for producing the landslide susceptibility map, landslide locations were identified from interpretation of aerial photographs and high resolution satellite images, field surveys and historical inventory reports. Landslide conditioning factors such as slope, plan curvature, distance to drainage lines, soil texture, lithology, and distance to lineament were extracted from topographic, soil, and lineament maps. Landslide susceptible areas were analyzed by the ANFIS model and mapped using the conditioning factors. Furthermore, we applied various membership functions (MFs) and fuzzy relations to produce landslide suscep-tibility maps. The prediction performance of the susceptibility map is checked by considering actual landslides in the study area. Results show that, triangular, trapezoidal, and polynomial MFs were the best individual MFs for modelling landslide susceptibility maps (86
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Human activity and damaging landslides and floods on Madeira Island
Baioni, D.
2011-11-01
Over the last few decades, the island of Madeira has become an important offshore tourism and business center, with rapid economic and demographic development that has caused changes to the landscape due to human activity. In Madeira's recent history, there has been an increase over time in the frequency of occurrence of damaging landslide and flood events. As a result, the costs of restoration work due to damage caused by landslide and flood events have become a larger and larger component of Madeira's annual budget. Landslides and floods in Madeira deserve particular attention because they represent the most serious hazard to human life, to property, and to the natural environment and its important heritage value. The work reported on in this paper involved the analysis of historical data regarding damaging landslide and flood events on Madeira (in particular from 1941 to 1991) together with data on geological characteristics, topographic features, and climate, and from field observations. This analysis showed that the main factor triggering the occurrence of damaging landslide and flood events is rainfall, but that the increase in the number of damaging events recorded on Madeira Island, especially in recent times, seems to be related mostly to human activity, specifically to economic development and population growth, rather than to natural factors.
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Estimate of landslide deformation and failure time by ESR technique of. alpha. -quartz
Energy Technology Data Exchange (ETDEWEB)
Xingzhong, Liang; Mingdong, Chen [Chengdu Coll. of Geology, SC (China); Jiyong, Chen; Jiamin, Feng [Sichuan Univ., Chengdu, SC (China)
1991-02-01
ESR dating has been applied to study landslides. A method of dose-difference to determine the landslide age has been developed. The ESR spectra of annealled quartz grain samples and the optimum conditions of thermal activation were studied. The signifcance of ESR dating of landslide in geological research was discussed.
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Seismic monitoring of soft-rock landslides: the Super-Sauze and Valoria case studies
Tonnellier, Alice; Helmstetter, Agnès; Malet, Jean-Philippe; Schmittbuhl, Jean; Corsini, Alessandro; Joswig, Manfred
2013-06-01
This work focuses on the characterization of seismic sources observed in clay-shale landslides. Two landslides are considered: Super-Sauze (France) and Valoria (Italy). The two landslides are developed in reworked clay-shales but differ in terms of dimensions and displacement rates. Thousands of seismic signals have been identified by a small seismic array in spite of the high-seismic attenuation of the material. Several detection methods are tested. A semi-automatic detection method is validated by the comparison with a manual detection. Seismic signals are classified in three groups based on the frequency content, the apparent velocity and the differentiation of P and S waves. It is supposed that the first group of seismic signals is associated to shearing or fracture events within the landslide bodies, while the second group may correspond to rockfalls or debris flows. A last group corresponds to external earthquakes. Seismic sources are located with an automatic beam-forming location method. Sources are clustered in several parts of the landslide in agreement with geomorphological observations. We found that the rate of rockfall and fracture events increases after periods of heavy rainfall or snowmelt. The rate of microseismicity and rockfall activity is also positively correlated with landslide displacement rates. External earthquakes did not influence the microseismic activity or the landslide movement, probably because the earthquake ground motion was too weak to trigger landslide events during the observation periods.
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Li, Yuanyao; Huang, Jinsong; Jiang, Shui-Hua; Huang, Faming; Chang, Zhilu
2017-12-07
It is important to monitor the displacement time series and to explore the failure mechanism of reservoir landslide for early warning. Traditionally, it is a challenge to monitor the landslide displacements real-timely and automatically. Globe Position System (GPS) is considered as the best real-time monitoring technology, however, the accuracies of the landslide displacements monitored by GPS are not assessed effectively. A web-based GPS system is developed to monitor the landslide displacements real-timely and automatically in this study. And the discrete wavelet transform (DWT) is proposed to assess the accuracy of the GPS monitoring displacements. Wangmiao landslide in Three Gorges Reservoir area in China is used as case study. The results show that the web-based GPS system has advantages of high precision, real-time, remote control and automation for landslide monitoring; the Root Mean Square Errors of the monitoring landslide displacements are less than 5 mm. Meanwhile, the results also show that a rapidly falling reservoir water level can trigger the reactivation of Wangmiao landslide. Heavy rainfall is also an important factor, but not a crucial component.
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The size, distribution, and mobility of landslides caused by the 2015 Mw7.8 Gorkha earthquake, Nepal
Roback, Kevin; Clark, Marin K.; West, A. Joshua; Zekkos, Dimitrios; Li, Gen; Gallen, Sean F.; Chamlagain, Deepak; Godt, Jonathan W.
2018-01-01
Coseismic landslides pose immediate and prolonged hazards to mountainous communities, and provide a rare opportunity to study the effect of large earthquakes on erosion and sediment budgets. By mapping landslides using high-resolution satellite imagery, we find that the 25 April 2015 Mw7.8 Gorkha earthquake and aftershock sequence produced at least 25,000 landslides throughout the steep Himalayan Mountains in central Nepal. Despite early reports claiming lower than expected landslide activity, our results show that the total number, area, and volume of landslides associated with the Gorkha event are consistent with expectations, when compared to prior landslide-triggering earthquakes around the world. The extent of landsliding mimics the extent of fault rupture along the east-west trace of the Main Himalayan Thrust and increases eastward following the progression of rupture. In this event, maximum modeled Peak Ground Acceleration (PGA) and the steepest topographic slopes of the High Himalaya are not spatially coincident, so it is not surprising that landslide density correlates neither with PGA nor steepest slopes on their own. Instead, we find that the highest landslide density is located at the confluence of steep slopes, high mean annual precipitation, and proximity to the deepest part of the fault rupture from which 0.5-2 Hz seismic energy originated. We suggest that landslide density was determined by a combination of earthquake source characteristics, slope distributions, and the influence of precipitation on rock strength via weathering and changes in vegetation cover. Determining the relative contribution of each factor will require further modeling and better constrained seismic parameters, both of which are likely to be developed in the coming few years as post-event studies evolve. Landslide mobility, in terms of the ratio of runout distance to fall height, is comparable to small volume landslides in other settings, and landslide volume-runout scaling is
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Pennington, Catherine; Freeborough, Katy; Dashwood, Claire; Dijkstra, Tom; Lawrie, Kenneth
2015-11-01
The British Geological Survey (BGS) is the national geological agency for Great Britain that provides geoscientific information to government, other institutions and the public. The National Landslide Database has been developed by the BGS and is the focus for national geohazard research for landslides in Great Britain. The history and structure of the geospatial database and associated Geographical Information System (GIS) are explained, along with the future developments of the database and its applications. The database is the most extensive source of information on landslides in Great Britain with over 17,000 records of landslide events to date, each documented as fully as possible for inland, coastal and artificial slopes. Data are gathered through a range of procedures, including: incorporation of other databases; automated trawling of current and historical scientific literature and media reports; new field- and desk-based mapping technologies with digital data capture, and using citizen science through social media and other online resources. This information is invaluable for directing the investigation, prevention and mitigation of areas of unstable ground in accordance with Government planning policy guidelines. The national landslide susceptibility map (GeoSure) and a national landslide domains map currently under development, as well as regional mapping campaigns, rely heavily on the information contained within the landslide database. Assessing susceptibility to landsliding requires knowledge of the distribution of failures, an understanding of causative factors, their spatial distribution and likely impacts, whilst understanding the frequency and types of landsliding present is integral to modelling how rainfall will influence the stability of a region. Communication of landslide data through the Natural Hazard Partnership (NHP) and Hazard Impact Model contributes to national hazard mitigation and disaster risk reduction with respect to weather and
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THE REDSHIFT DISTRIBUTION OF GIANT ARCS IN THE SLOAN GIANT ARCS SURVEY
International Nuclear Information System (INIS)
Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Oguri, Masamune; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon
2011-01-01
We measure the redshift distribution of a sample of 28 giant arcs discovered as a part of the Sloan Giant Arcs Survey. Gemini/GMOS-North spectroscopy provides precise redshifts for 24 arcs, and 'redshift desert' constrains for the remaining 4 arcs. This is a direct measurement of the redshift distribution of a uniformly selected sample of bright giant arcs, which is an observable that can be used to inform efforts to predict giant arc statistics. Our primary giant arc sample has a median redshift z = 1.821 and nearly two-thirds of the arcs, 64%, are sources at z ∼> 1.4, indicating that the population of background sources that are strongly lensed into bright giant arcs resides primarily at high redshift. We also analyze the distribution of redshifts for 19 secondary strongly lensed background sources that are not visually apparent in Sloan Digital Sky Survey imaging, but were identified in deeper follow-up imaging of the lensing cluster fields. Our redshift sample for the secondary sources is not spectroscopically complete, but combining it with our primary giant arc sample suggests that a large fraction of all background galaxies that are strongly lensed by foreground clusters reside at z ∼> 1.4. Kolmogorov-Smirnov tests indicate that our well-selected, spectroscopically complete primary giant arc redshift sample can be reproduced with a model distribution that is constructed from a combination of results from studies of strong-lensing clusters in numerical simulations and observational constraints on the galaxy luminosity function.
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Strauch, R. L.; Istanbulluoglu, E.
2017-12-01
We develop a landslide hazard modeling approach that integrates a data-driven statistical model and a probabilistic process-based shallow landslide model for mapping probability of landslide initiation, transport, and deposition at regional scales. The empirical model integrates the influence of seven site attribute (SA) classes: elevation, slope, curvature, aspect, land use-land cover, lithology, and topographic wetness index, on over 1,600 observed landslides using a frequency ratio (FR) approach. A susceptibility index is calculated by adding FRs for each SA on a grid-cell basis. Using landslide observations we relate susceptibility index to an empirically-derived probability of landslide impact. This probability is combined with results from a physically-based model to produce an integrated probabilistic map. Slope was key in landslide initiation while deposition was linked to lithology and elevation. Vegetation transition from forest to alpine vegetation and barren land cover with lower root cohesion leads to higher frequency of initiation. Aspect effects are likely linked to differences in root cohesion and moisture controlled by solar insulation and snow. We demonstrate the model in the North Cascades of Washington, USA and identify locations of high and low probability of landslide impacts that can be used by land managers in their design, planning, and maintenance.
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PaleoMac: A Macintosh™ application for treating paleomagnetic data and making plate reconstructions
Cogné, J. P.
2003-01-01
This brief note provides an overview of a new Macintosh™ application, PaleoMac, (MacOS 8.0 or later, 15Mb RAM required) which permits rapid processing of paleomagnetic data, from the demagnetization data acquired in the laboratory, to the treatment of paleomagnetic poles, plate reconstructions, finite rotation computations on a sphere, and characterization of relative plate motions. Capabilities of PaleoMac include (1) high interactivity between the user and data displayed on screen which provides a fast and easy way to handle, add and remove data or contours, perform computations on subsets of points, change projections, sizes, etc.; (2) performance of all standard principal component analysis and statistical processing on a sphere [, 1953] etc.); (3) output of high quality plots, compatible with graphic programs such as Adobe Illustrator, and output of numerical results as ASCII files. Beyond its usefulness in treating paleomagnetic data, its ability to handle plate motion computations should be of large interest to the Earth science community.
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International Nuclear Information System (INIS)
Loden, L.O.; Sundman, A.
1989-01-01
This study is part of an investigation of the possibility of using chemically peculiar (CP) stars to map local galactic structure. Correct luminosities of these stars are therefore crucial. CP stars are generally regarded as main-sequence or near-main-sequence objects. However, some CP stars have been classified as giants. A selection of stars, classified in literature as CP giants, are compared to normal stars in the same effective temperature interval and to ordinary 'non giant' CP stars. There is no clear confirmation of a higher luminosity for 'CP giants', than for CP stars in general. In addition, CP characteristics seem to be individual properties not repeated in a component star or other cluster members. (author). 50 refs., 5 tabs., 3 figs
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A Dynamic Hydrology-Critical Zone Framework for Rainfall-triggered Landslide Hazard Prediction
Dialynas, Y. G.; Foufoula-Georgiou, E.; Dietrich, W. E.; Bras, R. L.
2017-12-01
Watershed-scale coupled hydrologic-stability models are still in their early stages, and are characterized by important limitations: (a) either they assume steady-state or quasi-dynamic watershed hydrology, or (b) they simulate landslide occurrence based on a simple one-dimensional stability criterion. Here we develop a three-dimensional landslide prediction framework, based on a coupled hydrologic-slope stability model and incorporation of the influence of deep critical zone processes (i.e., flow through weathered bedrock and exfiltration to the colluvium) for more accurate prediction of the timing, location, and extent of landslides. Specifically, a watershed-scale slope stability model that systematically accounts for the contribution of driving and resisting forces in three-dimensional hillslope segments was coupled with a spatially-explicit and physically-based hydrologic model. The landslide prediction framework considers critical zone processes and structure, and explicitly accounts for the spatial heterogeneity of surface and subsurface properties that control slope stability, including soil and weathered bedrock hydrological and mechanical characteristics, vegetation, and slope morphology. To test performance, the model was applied in landslide-prone sites in the US, the hydrology of which has been extensively studied. Results showed that both rainfall infiltration in the soil and groundwater exfiltration exert a strong control on the timing and magnitude of landslide occurrence. We demonstrate the extent to which three-dimensional slope destabilizing factors, which are modulated by dynamic hydrologic conditions in the soil-bedrock column, control landslide initiation at the watershed scale.
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Data Mining Approaches for Landslide Susceptibility Mapping in Umyeonsan, Seoul, South Korea
Directory of Open Access Journals (Sweden)
Sunmin Lee
2017-07-01
Full Text Available The application of data mining models has become increasingly popular in recent years in assessments of a variety of natural hazards such as landslides and floods. Data mining techniques are useful for understanding the relationships between events and their influencing variables. Because landslides are influenced by a combination of factors including geomorphological and meteorological factors, data mining techniques are helpful in elucidating the mechanisms by which these complex factors affect landslide events. In this study, spatial data mining approaches based on data on landslide locations in the geographic information system environment were investigated. The topographical factors of slope, aspect, curvature, topographic wetness index, stream power index, slope length factor, standardized height, valley depth, and downslope distance gradient were determined using topographical maps. Additional soil and forest variables using information obtained from national soil and forest maps were also investigated. A total of 17 variables affecting the frequency of landslide occurrence were selected to construct a spatial database, and support vector machine (SVM and artificial neural network (ANN models were applied to predict landslide susceptibility from the selected factors. In the SVM model, linear, polynomial, radial base function, and sigmoid kernels were applied in sequence; the model yielded 72.41%, 72.83%, 77.17% and 72.79% accuracy, respectively. The ANN model yielded a validity accuracy of 78.41%. The results of this study are useful in guiding effective strategies for the prevention and management of landslides in urban areas.
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Evaluation of landslide susceptibility of Sete Cidades Volcano (S. Miguel Island, Azores
Directory of Open Access Journals (Sweden)
A. Gomes
2005-01-01
Full Text Available Sete Cidades is an active central volcano with a summit caldera located in the westernmost part of S. Miguel Island (Azores. Since the settlement of the Island, in the 15th century, many landslide events occurred in this volcano, causing extensive damages in buildings and infrastructures. The study of historical records and the observation of new occurrences showed that landslides in the region have been triggered by heavy rainfall periods, earthquakes and erosion. In order to assess landslide susceptibility at Sete Cidades Volcano, landslide scars and associated deposits were mapped through aerial photographs and field surveys. The obtained data were inserted in a GIS to produce a landslide distribution map. It was concluded that the high density landslide areas are related with (1 major scarp faults, (2 the margin of fluvial channels, (3 the sea cliffs and (4 volcanic landforms, namely the caldera wall. About 73% of the mapped events took place in areas where pyroclastic deposits are the dominant lithology and more than 77% occurred where slopes are equal or higher than 20°. These two parameters were integrated and used to generate a preliminary susceptibility map. The incorporation of vulnerability data into the GIS allowed concluding that 30% of dwellings and most of the roads on Sete Cidades Volcano are located in areas where landslide susceptibility is high to very high. Such conclusion should be taken into account for emergency and land use planning.
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Landslide Detection in the Carlyon Beach, WA Peninsula: Analysis Of High Resolution DEMs
Fayne, J.; Tran, C.; Mora, O. E.
2017-12-01
Landslides are geological events caused by slope instability and degradation, leading to the sliding of large masses of rock and soil down a mountain or hillside. These events are influenced by topography, geology, weather and human activity, and can cause extensive damage to the environment and infrastructure, such as the destruction of transportation networks, homes, and businesses. It is therefore imperative to detect early-warning signs of landslide hazards as a means of mitigation and disaster prevention. Traditional landslide surveillance consists of field mapping, but the process is expensive and time consuming. This study uses Light Detection and Ranging (LiDAR) derived Digital Elevation Models (DEMs) and k-means clustering and Gaussian Mixture Model (GMM) to analyze surface roughness and extract spatial features and patterns of landslides and landslide-prone areas. The methodology based on several feature extractors employs an unsupervised classifier on the Carlyon Beach Peninsula in the state of Washington to attempt to identify slide potential terrain. When compared with the independently compiled landslide inventory map, the proposed algorithm correctly classifies up to 87% of the terrain. These results suggest that the proposed methods and LiDAR-derived DEMs can provide important surface information and be used as efficient tools for digital terrain analysis to create accurate landslide maps.
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Seismically induced landslides: current research by the US Geological Survey.
Harp, E.L.; Wilson, R.C.; Keefer, D.K.; Wieczorek, G.F.
1986-01-01
We have produced a regional seismic slope-stability map and a probabilistic prediction of landslide distribution from a postulated earthquake. For liquefaction-induced landslides, in situ measurements of seismically induced pore-water pressures have been used to establish an elastic model of pore pressure generation. -from Authors
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Energy Technology Data Exchange (ETDEWEB)
Yoshioka, Ryuma; Mashima, Kiyotaka; Koizumi, Naoji
1988-10-01
A large-scale landslide took place at a southeastern slope of Mt. Jizuki, Nagano Prefecture, on July 26, 1985. It has been said that landslide is closely related to the hydrological and hydrogeochemical nature of groundwater involved. To investigate the weathering mechanism and the origin of groundwater, we collected and analyzed water samples from the large-scale landslide area. The following facts can be pointed out: (1) weather-rock interaction is remarkably active in the landslide area, (2) most of the waters from the landslide area are in equilibrium with Na-montmorillonite (3) immediately after the landslide occurred bicarbonate and sodium ions are dominant, but sulfate and sodium ions become dominant with time, and (4) groundwater passing through horizontally drilled holes dose not effectively drain off to stabilize a slope in the landslide area. And our hypothesis on the mechanism for the formation of sodium sulfate type water is also presented.
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Landslide rehabilitation with geo synthetics in open coal mine Oslomej
International Nuclear Information System (INIS)
Dimitrievski, Ljupcho; Ilievska, Frosina; Ilievski, Darko
2004-01-01
In November 2002 stability is violated and landslides are registered in open coal mine Oslomej, Republic of Macedonia. Around the profile IV existing open irrigation channel was interrupted and landslide was extended to the regional way R421 Kicevo - Oslomej. The landslide was classified like big and dangerous, including danger for disruption of the regional road and pipeline Studencica - Oslomej for supplying of thermal power plant Oslomej with technical water. According to the proposed solution, main project design for landslide rehabilitation was prepared with using geo synthetics Stabilenka 200/45. In fill is local soil material which had been placed and compacted in layers, it had formed a composite construction. Stabilenka acts as a reinforcement due to its ability to absorb tensile forces. With the design solution two retaining walls of reinforced soil and complete drainage system of geo composite materials had been constructed This paper deals with details of the design and the construction. (Author)
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PaleoClim: new datasets to quantify the impact of past climate changes on modern biodiversity
Hill, D. J.; Brown, J. T.; Carnaval, A. C.; Haywood, A. M.
2017-12-01
Palaeoclimate history is an important driver of modern patterns of biodiversity and many ecological modelling studies have shown the predictive power of palaeoclimate information. However, a major limiting factor to such studies is the availability of global palaeoclimate reconstructions in the relevant bioclim layers. The primary source of such fields is from climate model simulations, which are currently limited to the key PMIP (Paleoclimate Modelling Intercomparison Project) intervals of the mid-Holocene (6ka), the Last Glacial Maximum (21ka) and the Last Interglaciation (130ka). The PaleoClim project will significantly increase the availability of pre-processed palaeoclimate bioclim information and provide a new platform for accessing the information. The first new PaleoClim time period will be the mid-Pliocene Warm Period (3Ma). This is the last period of sustained globally warmer than modern climate in Earth history and represents the last global warmth before the cooling into the Pleistocene ice ages. Being 3 million years ago this represents a significant lengthening of the time range of available bioclim layers and the first time these have been available over evolutionary timescales. PaleoClim will also greatly expand the available Pleistocene time periods, looking to both quantify the differences between the late Pleistocene interglacial periods and understand the role of orbital changes in modulating tropical precipitation and driving modern biodiversity patterns.
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Harp, E.L.; Reid, M.E.; McKenna, J.P.; Michael, J.A.
2009-01-01
Loss of life and property caused by landslides triggered by extreme rainfall events demonstrates the need for landslide-hazard assessment in developing countries where recovery from such events often exceeds the country's resources. Mapping landslide hazards in developing countries where the need for landslide-hazard mitigation is great but the resources are few is a challenging, but not intractable problem. The minimum requirements for constructing a physically based landslide-hazard map from a landslide-triggering storm, using the simple methods we discuss, are: (1) an accurate mapped landslide inventory, (2) a slope map derived from a digital elevation model (DEM) or topographic map, and (3) material strength properties of the slopes involved. Provided that the landslide distribution from a triggering event can be documented and mapped, it is often possible to glean enough topographic and geologic information from existing databases to produce a reliable map that depicts landslide hazards from an extreme event. Most areas of the world have enough topographic information to provide digital elevation models from which to construct slope maps. In the likely event that engineering properties of slope materials are not available, reasonable estimates can be made with detailed field examination by engineering geologists or geotechnical engineers. Resulting landslide hazard maps can be used as tools to guide relocation and redevelopment, or, more likely, temporary relocation efforts during severe storm events such as hurricanes/typhoons to minimize loss of life and property. We illustrate these methods in two case studies of lethal landslides in developing countries: Tegucigalpa, Honduras (during Hurricane Mitch in 1998) and the Chuuk Islands, Micronesia (during Typhoon Chata'an in 2002).
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Web3DGIS-Based System for Reservoir Landslide Monitoring and Early Warning
Directory of Open Access Journals (Sweden)
Huang Huang
2016-02-01
Full Text Available Landslides are the most frequent type of natural disaster, and they bring about large-scale damage and are a threat to human lives and infrastructure; therefore, the ability to conduct real-time monitoring and early warning is important. In this study, a Web3DGIS (Web3D geographic information systems system for monitoring and forecasting landslides was developed using the Danjiangkou Reservoir area as a case study. The development of this technique involved system construction, functional design, organizing and managing multi-source spatial data, and implementing a forecasting plan and landslide-forecasting model. By integrating sensor technologies, spatial information technologies, 3D visualization technologies, and a landslide-forecasting model, the results of this study provide a tool for real-time monitoring at potential landslide sites. When relevant data from these sites reach threshold values, the model automatically initiates forecasting procedures, and sends information to disaster prevention sectors for emergency management.
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Gariano, Stefano Luigi; Brunetti, Maria Teresa; Iovine, Giulio; Melillo, Massimo; Peruccacci, Silvia; Terranova, Oreste Giuseppe; Vennari, Carmela; Guzzetti, Fausto
2015-04-01
Prediction of rainfall-induced landslides can rely on empirical rainfall thresholds. These are obtained from the analysis of past rainfall events that have (or have not) resulted in slope failures. Accurate prediction requires reliable thresholds, which need to be validated before their use in operational landslide warning systems. Despite the clear relevance of validation, only a few studies have addressed the problem, and have proposed and tested robust validation procedures. We propose a validation procedure that allows for the definition of optimal thresholds for early warning purposes. The validation is based on contingency table, skill scores, and receiver operating characteristic (ROC) analysis. To establish the optimal threshold, which maximizes the correct landslide predictions and minimizes the incorrect predictions, we propose an index that results from the linear combination of three weighted skill scores. Selection of the optimal threshold depends on the scope and the operational characteristics of the early warning system. The choice is made by selecting appropriately the weights, and by searching for the optimal (maximum) value of the index. We discuss weakness in the validation procedure caused by the inherent lack of information (epistemic uncertainty) on landslide occurrence typical of large study areas. When working at the regional scale, landslides may have occurred and may have not been reported. This results in biases and variations in the contingencies and the skill scores. We introduce two parameters to represent the unknown proportion of rainfall events (above and below the threshold) for which landslides occurred and went unreported. We show that even a very small underestimation in the number of landslides can result in a significant decrease in the performance of a threshold measured by the skill scores. We show that the variations in the skill scores are different for different uncertainty of events above or below the threshold. This