Sample records for chuetsu-oki earthquake influences

  1. Field reconnaissance of the 2007 Niigata-Chuetsu Oki earthquake

    Institute of Scientific and Technical Information of China (English)

    Georgios Apostolakis; Bing Qu; Nurhan Ecemis; Seda Dogruel


    As part of the 2007 Yri-Center Field Mission to Japan,a reconnaissance team comprised of fourteen graduate students and three faculty members from three U.S. earthquake engineering research centers,namely,Multidisciplinary Center for Earthquake Engineering Research (MCEER),Mid-America Earthquake Center(MAE),and Pacific Earthquake Engineering Research Center (PEER),undertook a reconnaissance visit to the affected area shortly after the 2007 NiigataChuetsu Oki earthquake.This mission provided an opportunity to review the nature of the earthquake damage that occurred,as well as to assess the significance of the damage from an educational perspective.This paper reports on the seismological characteristics of the earthquake,preliminary findings of geotechnical and structural damage,and the causes of the observed failures or collapses.In addition,economic and socio-economic considerations and experiences to enhance earthquake resilience are presented.

  2. Field reconnaissance of the 2007 Niigata-Chuetsu Oki earthquake (United States)

    Apostolakis, Georgios; Qu, Bing; Ecemis, Nurhan; Dogruel, Seda


    As part of the 2007 Tri-Center Field Mission to Japan, a reconnaissance team comprised of fourteen graduate students and three faculty members from three U.S. earthquake engineering research centers, namely, Multidisciplinary Center for Earthquake Engineering Research (MCEER), Mid-America Earthquake Center (MAE), and Pacific Earthquake Engineering Research Center (PEER), undertook a reconnaissance visit to the affected area shortly after the 2007 Niigata-Chuetsu Oki earthquake. This mission provided an opportunity to review the nature of the earthquake damage that occurred, as well as to assess the significance of the damage from an educational perspective. This paper reports on the seismological characteristics of the earthquake, preliminary findings of geotechnical and structural damage, and the causes of the observed failures or collapses. In addition, economic and socio-economic considerations and experiences to enhance earthquake resilience are presented.

  3. Geoengineering and seismological aspects of the Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 (United States)

    Kayen, R.; Brandenberg, S.J.; CoIlins, B.D.; Dickenson, S.; Ashford, S.; Kawamata, Y.; Tanaka, Y.; Koumoto, H.; Abrahamson, N.; Cluff, L.; Tokimatsu, K.


    The M6.6 Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 occurred off the west coast of Japan with a focal depth of 10 km, immediately west of Kashiwazaki City and Kariwa Village in southern Niigata Prefecture. Peak horizontal ground accelerations of 0.68 g were measured in Kashiwazaki City, as well as at the reactor floor level of the world's largest nuclear reactor, located on the coast at Kariwa Village. Liquefaction of historic and modern river deposits, aeolian dune sand, and manmade fill was widespread in the coastal region nearest the epicenter and caused ground deformations that damaged bridges, embankments, roadways, buildings, ports, railways and utilities. Landslides along the coast of southern Niigata Prefecture and in mountainous regions inland of Kashiwazaki were also widespread affecting transportation infrastructure. Liquefaction and a landslide also damaged the nuclear power plant sites. This paper, along with a companion digital map database available at http://walrus.wr.usgs.gOv/infobank/n/nii07jp/html/n-ii-07-jp.sites.kmz, describes the seismological and geo-engineering aspects of the event. ?? 2009, Earthquake Engineering Research Institute.


    Itoh, Kazuya; Noda, Masashi; Kikkawa, Naotaka; Hori, Tomohito; Tamate, Satoshi; Toyosawa, Yasuo; Suemasa, Naoaki

    Labour accidents in disaster-relief and disaster restoration work following the Niigata Chuetsu Earthquake (2004) and the Niigata Chuetsu-oki Earthquake (2007) were analysed and characterised in order to raise awareness of the risks and hazards in such work. The Niigata Chuetsu-oki Earthquake affected houses and buildings rather than roads and railways, which are generally disrupted due to landslides or slope failures caused by earthquakes. In this scenario, the predominant type of accident is a "fall to lower level," which increases mainly due to the fact that labourers are working to repair houses and buildings. On the other hand, landslides and slope failures were much more prevalent in the Niigata Chuetsu Earthquake, resulting in more accidents occurring in geotechnical works rather than in construction works. Therefore, care should be taken in preventing "fall to lower level" accidents associated with repair work on the roofs of low-rise houses, "cut or abrasion" accidents due to the demolition of damaged houses and "caught in or compressed by equipment" accidents in road works and water and sewage works.

  5. Seismological asperities from the point of view of dynamic rupture modeling: the 2007 Mw6.6 Chuetsu-Oki, Japan, earthquake (United States)

    Aochi, Hideo; Yoshimi, Masayuki


    We study the ground motion simulations based on three finite-source models for the 2007 Mw6.6 Niigata Chuetsu-oki, Japan, earthquake in order to discuss the performance of the input ground motion estimations for the near-field seismic hazard analysis. The three models include a kinematic source inverted from the regional accelerations, a dynamic source on a planar fault with three asperities inferred from the very-near-field ground motion particle motions, and another dynamic source model with conjugate fault segments. The ground motions are calculated for an available 3D geological model using a finite-difference method. For the comparison, we apply a goodness-of-fit score to the ground motion parameters at different stations, including the nearest one that is almost directly above the ruptured fault segments. The dynamic rupture models show good performance. We find that seismologically inferred earthquake asperities on a single fault plane can be expressed with two conjugate segments. The rupture transfer from one segment to another can generate a significant radiation; this could be interpreted as an asperity projected onto a single fault plane. This example illustrates the importance of the fault geometry that has to be taken into account when estimating the very-near-field ground motion.

  6. Concerns of Disaster Medical Assistance Team (DMAT) members about troubles at the nuclear power plant: experience from the Niigata Chuetsu-Oki earthquake, 16 July 2007, in Japan. (United States)

    Akashi, Makoto; Kumagaya, Ken; Kondo, Hisayoshi; Hirose, Yasuo


    An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 10:13 on 16 July 2007. The earthquake was followed by the sustained occurrence of numerous aftershocks, delaying the reconstruction of community lifelines. The earthquake affected the Kashiwazaki-Kariwa nuclear power plants (NPPs), the biggest NPP site in the world. The earthquake caused damage to NPPs, resulting in a small amount of radioactive materials being released into the air and the sea. However, no significant effects were detected in the public and the environment. As medical response to this earthquake, 42 Disaster Medical Assistance Teams (DMATs) were sent to hospitals and first-aid care centers at the NPP site. In order to evaluate the perceptions of the deployed DMAT personnel regarding concerns about the health effects of radiation and information about the damage to NPPs, questionnaires were sent to 40 facilities that dispatched DMATs to the earthquake area. Most of them were concerned with the effects of radiation, and adequate information about the problems at the NPPs was not communicated to them. This preliminary study suggests that communication of information is extremely important for DMAT members in the case of disasters, in particular if there exists a possibility of radiation exposure, since radiation cannot be detected by our senses. DMAT members are critical to any mass casualty incident, whether caused by humans or nature. We have learned from this earthquake that there is urgent need for an all-hazards approach, including a "combined disaster" strategy, which should be emphasized for current disaster planning and response. This is the first report on DMATs deployed to an earthquake site with damage to NPPs.

  7. Analysis of the strong motion records obtained from the 2007 Niigataken Chuetsuoki earthquake and determination of the design basis ground motions at the Kashiwazaki Kariwa Nuclear Power Plant. Part 1. Outline of the strong motion records and estimation of factors in large amplification

    Energy Technology Data Exchange (ETDEWEB)

    Tokumitsu, Ryoichi; Kikuchi, Masatomo; Nishimura, Isao (Nuclear Asset Management Dept., Tokyo Electric Power Company, Tokyo (Japan)), e-mail:; Shiba, Yoshiaki (Earthquake Engineering Sector, Central Research Inst. of Electric Power Industry, Chiba (Japan)), e-mail:; Tanaka, Shinya (Architectural Dept., Tokyo Electric Power Services CO., LTD.,Tokyo (Japan)), e-mail:


    In order to investigate the primary factor of the large ground motion observed at the Kashiwazaki Kariwa Nuclear Power Plant in the Niigataken Chuetsu-Oki Earthquake, the source, propagation and site effect of the Niigataken Chuetsu-Oki Earthquake, with the analysis and ground motion simulation analysis of observation record was examined


    Toyosawa, Yasuo; Itoh, Kazuya; Kikkawa, Naotaka

    Occupational safety and health in disaster restoration activity following the Great Hanshin Earthquake (1995), Niigata Chuetsu Earthquake (2004), Niigata Chuetsu-oki Earthquake (2007) Great East Japan Earthquake (2011) were analyzed and characterized in order to raise awareness on the risks and hazards in such work. In this scenario, the predominant type of accident is a "fall" which increases mainly due to the fact that labourers are working to repair houses and buildings. On the other hand, landslides were prevalent in the Niigata Chuetsu Earthquake, resulting in more accidents occurring during geotechnical works rather than in buildings construction works. In the abnormal conditions that characterize recovery activities, when safety and health measures have a tendency to be neglected, it is important to reinstate adequate measures as soon as possible by carrying out the usial risk assessments.

  9. Atmospheric Signals Associated with Major Earthquakes. A Multi-Sensor Approach. Chapter 9 (United States)

    Ouzounov, Dimitar; Pulinets, Sergey; Hattori, Katsumi; Kafatos, Menas; Taylor, Patrick


    We are studying the possibility of a connection between atmospheric observation recorded by several ground and satellites as earthquakes precursors. Our main goal is to search for the existence and cause of physical phenomenon related to prior earthquake activity and to gain a better understanding of the physics of earthquake and earthquake cycles. The recent catastrophic earthquake in Japan in March 2011 has provided a renewed interest in the important question of the existence of precursory signals preceding strong earthquakes. We will demonstrate our approach based on integration and analysis of several atmospheric and environmental parameters that were found associated with earthquakes. These observations include: thermal infrared radiation, radon! ion activities; air temperature and humidity and a concentration of electrons in the ionosphere. We describe a possible physical link between atmospheric observations with earthquake precursors using the latest Lithosphere-Atmosphere-Ionosphere Coupling model, one of several paradigms used to explain our observations. Initial results for the period of2003-2009 are presented from our systematic hind-cast validation studies. We present our findings of multi-sensor atmospheric precursory signals for two major earthquakes in Japan, M6.7 Niigata-ken Chuetsu-oki of July16, 2007 and the latest M9.0 great Tohoku earthquakes of March 11,2011

  10. A new algorithm to find earthquake clusters using neighboring cell connection and rate analysis. (United States)

    Peng, W.; Toda, S.


    To study earthquake interaction, it is important to objectively find a group of earthquakes occurred closely in space and time. Earthquake clusters are chosen with previous techniques that characterize them as mainshock-aftershock sequences or swarm sequences by empirical laws (e.g., Omori-Utsu; ETAS) or direct assumptions about physical processes such as stress transfer, transient stress loading, and fluid migration. Recent papers instead proposed non-parameterized techniques such as a kernel-based smoothing method. The cumulative rate clustering method (CURATE, Jacobs et al., 2013) is one of the approaches without any direct assumptions. The CURATE method was applied in New Zealand and provided a good result for selecting the swarm sequences comparing with the ETAS model. However, it is still difficult to choose a proper confined area and a time interval for extracting sequences from the catalog. To avoid arbitrariness in space and time parameters, here we propose a new method modifying the CURATE approach. We first identify the spatial clusters by looking into the spatial distribution in a 2-D cell-gridded map. The spatial clusters defined as multiple neighboring cells, each of which contains at least one earthquake in a time period T. From the selected spatial clusters, we then evaluate temporal clustering which is defined as a transient increase of seismicity rate comparing to the rate before the target event. We tested this method focusing on shallow crustal seismicity, northern Honshu, Japan. We chose the parameter range from T = 1 to 100 days and cell size = 0.01°to 0.1°. As a result, the number of the clusters increase with longer T and larger cell size. By choosing the T = 30 days and cell size = 0.05°, we successfully selected the long-lasting aftershock sequences associated with the 2004 M6.8 Chuetsu and 2007 M6.8 Chuetsu-oki earthquakes, while other empirical models and CURATE method failed to decluster.

  11. Influence of Japan Earthquake Upon Shipbuilding Industry

    Institute of Scientific and Technical Information of China (English)

    Sun Jianmiao


    On March 11,the strong earthquake of 9.0 magnitude and the tsunami in Japan made its entire social life,production and communication systems into chaos.As the world third largest economy.Japan is also a large trade,shipbuilding and marine equipment manufacturing country.The earthquake has not only greatly affected the Japanese shipbuilding industry,but also the international shipping industry and Chinese shipbuilding industry.

  12. Influence length and space-time correlation between earthquakes

    CERN Document Server

    Tosi, P; Loreto, V; Pietronero, L; Tosi, Patrizia; Rubeis, Valerio De; Loreto, Vittorio; Pietronero, Luciano


    Short and long range interactions between earthquakes are attracting increasing interest. Scale invariant properties of seismicity in time, space and energy argue for the presence of complex triggering mechanisms where, like a cascade process, each event produces aftershocks. A definitive method to assess any connection between two earthquakes separated in time and distance does not exist. Here we propose a novel method of data analysis that, based on the space-time combined generalization of the correlation integral leads to a self-consistent visualization and analysis of both spatial and temporal correlations. When analyzing global seismicity we discovered a universal relation linking the spatial Influence Length of a given earthquake to the time elapsed from the event itself. Following an event, time correlations (i.e. causality effects) exist in a region that shrinks over time, suggesting a long-range dissipating stress transfer. A different process is acting in the short-range where events are randomly s...

  13. Characterising large scenario earthquakes and their influence on NDSHA maps (United States)

    Magrin, Andrea; Peresan, Antonella; Panza, Giuliano F.


    The neo-deterministic approach to seismic zoning, NDSHA, relies on physically sound modelling of ground shaking from a large set of credible scenario earthquakes, which can be defined based on seismic history and seismotectonics, as well as incorporating information from a wide set of geological and geophysical data (e.g. morphostructural features and present day deformation processes identified by Earth observations). NDSHA is based on the calculation of complete synthetic seismograms; hence it does not make use of empirical attenuation models (i.e. ground motion prediction equations). From the set of synthetic seismograms, maps of seismic hazard that describe the maximum of different ground shaking parameters at the bedrock can be produced. As a rule, the NDSHA, defines the hazard as the envelope ground shaking at the site, computed from all of the defined seismic sources; accordingly, the simplest outcome of this method is a map where the maximum of a given seismic parameter is associated to each site. In this way, the standard NDSHA maps permit to account for the largest observed or credible earthquake sources identified in the region in a quite straightforward manner. This study aims to assess the influence of unavoidable uncertainties in the characterisation of large scenario earthquakes on the NDSHA estimates. The treatment of uncertainties is performed by sensitivity analyses for key modelling parameters and accounts for the uncertainty in the prediction of fault radiation and in the use of Green's function for a given medium. Results from sensitivity analyses with respect to the definition of possible seismic sources are discussed. A key parameter is the magnitude of seismic sources used in the simulation, which is based on information from earthquake catalogue, seismogenic zones and seismogenic nodes. The largest part of the existing Italian catalogues is based on macroseismic intensities, a rough estimate of the error in peak values of ground motion can

  14. Earthquake

    Institute of Scientific and Technical Information of China (English)


    正A serious earthquake happened in Wenchuan, Sichuan. Over 60,000 people died in the earhtquake, millins of people lost their homes. After the earthquake, people showed their love in different ways. Some gave food, medicine and everything necessary, some gave money,

  15. Earthquake potential revealed by tidal influence on earthquake size-frequency statistics (United States)

    Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki


    The possibility that tidal stress can trigger earthquakes is long debated. In particular, a clear causal relationship between small earthquakes and the phase of tidal stress is elusive. However, tectonic tremors deep within subduction zones are highly sensitive to tidal stress levels, with tremor rate increasing at an exponential rate with rising tidal stress. Thus, slow deformation and the possibility of earthquakes at subduction plate boundaries may be enhanced during periods of large tidal stress. Here we calculate the tidal stress history, and specifically the amplitude of tidal stress, on a fault plane in the two weeks before large earthquakes globally, based on data from the global, Japanese, and Californian earthquake catalogues. We find that very large earthquakes, including the 2004 Sumatran, 2010 Maule earthquake in Chile and the 2011 Tohoku-Oki earthquake in Japan, tend to occur near the time of maximum tidal stress amplitude. This tendency is not obvious for small earthquakes. However, we also find that the fraction of large earthquakes increases (the b-value of the Gutenberg-Richter relation decreases) as the amplitude of tidal shear stress increases. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. This suggests that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. We conclude that large earthquakes are more probable during periods of high tidal stress.

  16. Influence of Earthquake Parameters on Tsunami Wave Height and Inundation (United States)

    Kulangara Madham Subrahmanian, D.; Sri Ganesh, J.; Venkata Ramana Murthy, M.; V, R. M.


    After Indian Ocean Tsunami (IOT) on 26th December, 2004, attempts are being made to assess the threat of tsunami originating from different sources for different parts of India. The Andaman - Sumatra trench is segmented by transcurrent faults and differences in the rate of subduction which is low in the north and increases southward. Therefore key board model with initial deformation calculated using different strike directions, slip rates, are used. This results in uncertainties in the earthquake parameters. This study is made to identify the location of origin of most destructive tsunami for Southeast coast of India and to infer the influence of the earthquake parameters in tsunami wave height travel time in deep ocean as well as in the shelf and inundation in the coast. Five tsunamigenic sources were considered in the Andaman - Sumatra trench taking into consideration the tectonic characters of the trench described by various authors and the modeling was carried out using TUNAMI N2 code. The model results were validated using the travel time and runup in the coastal areas and comparing the water elevation along Jason - 1's satellite track. The inundation results are compared from the field data. The assessment of the tsunami threat for the area south of Chennai city the metropolitan city of South India shows that a tsunami originating in Car Nicobar segment of the Andaman - Sumatra subduction zone can generate the most destructive tsunami. Sensitivity analysis in the modelling indicates that fault length influences the results significantly and the tsunami reaches early and with higher amplitude. Strike angle is also modifying the tsunami followed by amount of slip.


    Directory of Open Access Journals (Sweden)

    Yesugey Sadik Cengiz


    Full Text Available Earthquakes are tectonic events that take place within the fractures of the earth's crust, namely faults. Above certain scale, earthquakes can result in widespread fatalities and substantial financial loss. In addition to the movement of tectonic plates relative to each other, it is widely discussed that there are other external influences originate outside earth that can trigger earthquakes. These influences are called "triggering effects". The purpose of this article is to present a statistical view to elaborate if the solar geomagnetic storms trigger earthquakes.As a model, the research focuses on the Anatolian peninsula, presenting 41 years of historical data on magnetic storms and earthquakes collated from national and international resources. As a result of the comparative assessment of the data, it is concluded that the geomagnetic storms do not trigger earthquakes.

  18. Influence of Oil Reservoir on Earthquake (IORE Theory

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Masoumi


    Full Text Available The effect of oil reservoirs on intensity of earthquake has been discussed in this paper. The data for this research have been obtained from IRIS Earthquake Browser which has given earthquake data for South West of Iran, where there are high pressure oil fields. In this article, attempt has been made to show seismicity of oil fields that has been changing with time. Some simple simulation experiments were also performed to get a relation between mechanical vibration through some compact soil in a box and absorption of these vibrations by a water bag which was placed underneath the soil, inside the box. The results were used to explain absorption of an earthquake impact by an oil reservoir and oil reservoirs work as dampers.

  19. Influence of hydrodynamic parameters on tsunami run-up uncertainty induced by earthquake random slip distribtutions (United States)

    Løvholt, Finn; Kim, Jihwan; Pedersen, Geir; Harbitz, Carl


    The standard approach in forward modeling of earthquake tsunamis usually assume a uniform slip pattern. This is assumption is used both in deterministic and probabilistic models. However, the slip distribution for an earthquake is subject to (aleatory) uncertainty, and consequently the induced tsunami run-up will have an uncertainty range even given the same moment magnitude and hypocentre earthquake location. Here, we present studies of run-up variability due to stochastic earthquake slip variation in both two and three dimensions. The approach taken is fully idealized, although we draw upon the experience from two of the most destructive events the last hundred years, namely the Mw8 1976 Moro Gulf earthquake and tsunami as well as the Mw9 2011 Tohoku earthquake tsunami. The former event is used to design the two-dimensional stochastic simulations, and the latter event the three-dimensional simulations. Our primary focus is not reproduce past run-up, but rather to investigate how the hydrodynamics influence uncertainty. These quantities include among others the non-hydrodynamic response during generation, frequency dispersion, friction from the seabed, and wave-breaking. We simulate tsunamis for an ensemble of synthetic random slip over an idealized shelf geometry broken into linear segments. The uncertainty propagation from source to run-up for the two different cases are discussed and compared. As demonstrated, both the dimensionality and the earthquake parameters influence the contributions of the hydrodynamic parameters on the uncertainty. Further work will be needed to explore the transitional behaviour between the two very different cases displayed here. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement 603839 (Project ASTARTE).

  20. The Influencing Factors of Escaped Radon from the Jiayuguan Fault Zone and Its Earthquake Reflecting Effect

    Institute of Scientific and Technical Information of China (English)

    Wang Bo; Huang Fuqiong; Jian Chunlin


    The paper analyzes the radon data of nearly two decades on the Jiayuguan fault zone, discusses the main influencing factors, and puts forward the relationship between radon and air temperature, ground temperature and rainfall. We summarized the earthquake reflecting effect for ML≥5. 0 about 400km within the Jiayuguan station, and reached the conclusion that it has better earthquake-reflecting ability before an earthquake, usually appearing as abnormal changes in sustained low value. By extracting the annual trend of radon in Jiayuguan station over many years, we discovered that the annual trend of radon has a close relationship with the seismic activity in surrounding areas, namely, if the annual variation of radon is larger, the seismic activity in surrounding areas is stronger; Otherwise, if the annual variation of radon is relatively stable, the seismic activity in the vicinity is weak.

  1. Isolating social influences on vulnerability to earthquake shaking: identifying cost-effective mitigation strategies. (United States)

    Bhloscaidh, Mairead Nic; McCloskey, John; Pelling, Mark; Naylor, Mark


    Until expensive engineering solutions become more universally available, the objective targeting of resources at demonstrably effective, low-cost interventions might help reverse the trend of increasing mortality in earthquakes. Death tolls in earthquakes are the result of complex interactions between physical effects, such as the exposure of the population to strong shaking, and the resilience of the exposed population along with supporting critical infrastructures and institutions. The identification of socio-economic factors that contribute to earthquake mortality is crucial to identifying and developing successful risk management strategies. Here we develop a quantitative methodology more objectively to assess the ability of communities to withstand earthquake shaking, focusing on, in particular, those cases where risk management performance appears to exceed or fall below expectations based on economic status. Using only published estimates of the shaking intensity and population exposure for each earthquake, data that is available for earthquakes in countries irrespective of their level of economic development, we develop a model for mortality based on the contribution of population exposure to shaking only. This represents an attempt to remove, as far as possible, the physical causes of mortality from our analysis (where we consider earthquake engineering to reduce building collapse among the socio-economic influences). The systematic part of the variance with respect to this model can therefore be expected to be dominated by socio-economic factors. We find, as expected, that this purely physical analysis partitions countries in terms of basic socio-economic measures, for example GDP, focusing analytical attention on the power of economic measures to explain variance in observed distributions of earthquake risk. The model allows the definition of a vulnerability index which, although broadly it demonstrates the expected income-dependence of vulnerability to

  2. Revisiting the global detection capability of earthquakes during the period immediately after a large earthquake: considering the influence of intermediate-depth and deep earthquakes

    Directory of Open Access Journals (Sweden)

    Takaki Iwata


    Full Text Available This study examines the global earthquake detection capability of the Global Centroid Moment Tensor (GCMT catalogue during the periods immediately following large earthquakes, including intermediate-depth (70 ≤ depth < 300 km and deep (300 km ≤ depth events. We have already shown that the detection capability beyond an aftershock zone degrades remarkably and that this condition persists for several hours after the occurrence of large shallow (depth < 70 km earthquakes. Because an intermediate-depth or deep earthquake occasionally generates seismic waves with significant amplitudes, it is necessary to investigate the change in the detection capability caused by such events. To this end, from the GCMT catalogue, we constructed the time sequences of the earthquakes that occurred immediately after the large earthquakes, and stacked these time sequences. To these stacked sequences, we then applied a statistical model representing the magnitude-frequency distribution of all observed earthquakes. This model has a parameter that characterizes the detection capability, and the temporal variation of the parameter is estimated by means of a Bayesian approach with a piecewise linear function. Consequently, we find that the global detection capability is lower after the occurrence of shallow earthquakes with magnitudes ≥ 5.45, intermediate-depth earthquakes with magnitudes ≥ 5.95, and deep earthquakes with magnitudes ≥ 6.95.

  3. Rapid Ice Mass Loss: Does It Have an Influence on Earthquake Occurrence in Southern Alaska? (United States)

    Sauber, Jeanne M.


    The glaciers of southern Alaska are extensive, and many of them have undergone gigatons of ice wastage on time scales on the order of the seismic cycle. Since the ice loss occurs directly above a shallow main thrust zone associated with subduction of the Pacific-Yakutat plate beneath continental Alaska, the region between the Malaspina and Bering Glaciers is an excellent test site for evaluating the importance of recent ice wastage on earthquake faulting potential. We demonstrate the influence of cumulative glacial mass loss following the 1899 Yakataga earthquake (M=8.1) by using a two dimensional finite element model with a simple representation of ice fluctuations to calculate the incremental stresses and change in the fault stability margin (FSM) along the main thrust zone (MTZ) and on the surface. Along the MTZ, our results indicate a decrease in FSM between 1899 and the 1979 St. Elias earthquake (M=7.4) of 0.2 - 1.2 MPa over an 80 km region between the coast and the 1979 aftershock zone; at the surface, the estimated FSM was larger but more localized to the lower reaches of glacial ablation zones. The ice-induced stresses were large enough, in theory, to promote the occurrence of shallow thrust earthquakes. To empirically test the influence of short-term ice fluctuations on fault stability, we compared the seismic rate from a reference background time period (1988-1992) against other time periods (1993-2006) with variable ice or tectonic change characteristics. We found that the frequency of small tectonic events in the Icy Bay region increased in 2002-2006 relative to the background seismic rate. We hypothesize that this was due to a significant increase in the rate of ice wastage in 2002-2006 instead of the M=7.9, 2002 Denali earthquake, located more than 100km away.

  4. A search for connections of gravitational influence of the Moon and the Sun with earthquakes of Carpathian region of Ukraine (United States)

    Kazantsev, A. M.; Kazantseva, L.


    If there is an influence of the Moon and Sun on the occurrence of earthquakes, the physical nature of such influence can only be the gravitational. A possible gravitational influence is caused by the resultant tidal forces of the Moon and the Sun, but not by their separate actions. The calculations algorithm for the tidal forces of the Sun and Moon and for their resultant is described. Relative changes of these forces for different zones on the earth's surface in time and at various depths are presented. Preliminary recommendations for searching of connections of gravitational influence of the Moon and the Sun with earthquakes was made.

  5. Influence of earthquake ground motion incoherency on multi-support structures

    Institute of Scientific and Technical Information of China (English)


    A linear response history analysis method is used to determine the influence of three factors: geometric incoherency, wave-passage, and local site characteristics on the response of multi-support structures subjected to differential ground motions. A one-span frame and a reduced model of a 24-span bridge, located in Las Vegas, Nevada are studied, in which the influence of each of the three factors and their combinations are analyzed. It is revealed that the incoherency of earthquake ground motion can have a dramatic influence on structural response by modifying the dynamics response to uniform excitation and inducing pseudo-static response, which does not exist in structures subjected to uniform excitation. The total response when all three sources of ground motion incoherency are included is generally larger than that of uniform excitation.

  6. Understanding Space Weather influence on earthquake triggering to shield people living in seismic regions (United States)

    Khachikyan, Galina; Inchin, Alexander; Kim, Alexander; Khassanov, Eldar


    There is an idea at present that space weather can influence not only the technological infrastructure and people's health, but seismic activity as well. Space weather impact on the Earth results from magnetic reconnection between the Sun's and Earth's magnetic fields. The effectiveness of reconnection depends on sign and magnitude of Z-components in solar wind magnetic field and earth's magnetic field as measured in the geocentric solar magnetosphere (GSM) coordinate system. The more negative value of Zgsm in the solar wind magnetic field, and the more positive value of Zgsm in the geomagnetic field, the more solar wind energy penetrates into the earth's environment due to reconnection. It was found recently by Khachikyan et al. [2012,] that maximal possible earthquake magnitude in a particular seismic region (seismic potential - Mmax) may be determined, in first approximation, on the base of maximal geomagnetic Zgsm value in this region, namely: Mmax = (5.22 +- 0.17) + (0.78 +- 0.06) x [abs (Zgsm)]. In this report we present statistical results on association between variations in space weather and global seismic activity, and demonstrate that a great Sumatra earthquake (M=9.1, on December 26, 2004, at 00:58:53 GMT) indeed occurred in region where the geomagnetic Zgsm components are largest at the globe. In the time of earthquake occurrence, geomagnetic Zgsm value in the epicenter (3.30N, 95.980E) was equal to ~37147 nT. A range of possible maximal magnitude, as estimated from above relation, could be of 8.8 - 9.2. The recorded magnitude M=9.1 is within this range.

  7. Influence of Forearc Structure on the Extent of Great Subduction Zone Earthquakes (United States)

    McGuire, J. J.; Llenos, A.


    Structural features associated with forearc basins appear to strongly influence the rupture processes of large subduction zone earthquakes. Recent studies demonstrated that a significant percentage of the global seismic moment release on subduction zone thrust faults is concentrated beneath the gravity lows resulting from forearc basins. To better determine the nature of this correlation and examine its effect on rupture directivity and termination, we estimated the rupture areas of a set of Mw 7.5-8.7 earthquakes that occurred in circum-Pacific subduction zones. We compare synthetic and observed seismograms by measuring frequency- dependent amplitude and arrival time differences of the first orbit Rayleigh waves. At low frequencies, the amplitude anomalies primarily result from the spatial and temporal extent of the rupture. We then invert the amplitude and arrival time measurements to estimate the second moments of the slip distribution which describe the rupture length, width, duration and propagation velocity of each earthquake. Comparing the rupture areas to the trench-parallel gravity anomaly (TPGA, Song and Simons 2003) above each rupture, we find that in 12 of the 14 events considered in this study the TPGA increases between the centroid and the limits of the rupture. Thus, local increases in TPGA appear to be related to the physical conditions along the plate interface that favor rupture termination. Owing to the inherently long time scales required for forearc basin formation, the correlation between the TPGA field and rupture termination regions indicates that long-lived material heterogeneity rather than short time-scale stress heterogeneities are responsible for arresting most great subduction zone ruptures.

  8. Influence of the Kunlun Mountain Ms8.1 Earthquake on Horizontal Crustal Deformation in the Sichuan and Yunnan Area

    Institute of Scientific and Technical Information of China (English)


    In order to track the space-time variation of regional strain field holistically (in a large scale)and to describe the regional movement field more objectively, the paper uses a nonlinear continuous strain model focused on extracting medium-low frequency strain information on the basis of a region with no rotation. According to the repeated measurements (1999 ~ 2001 ~2004) from GPS monitoring stations in the Sichuan and Yunnan area obtained by the Project of "China Crust Movement Measuring Network", and with the movement of 1999 ~ 2001 (stage deformation background) as the basic reference, we separated the main influencing factors of the Kunlun Mountain Ms8. 1 earthquake in 2001 from the data of 2001 and 2004, and the results indicate: (1) the Kunlun Mountain Ms8.1 earthquake has a discriminating effect on the Sichuan and Yunnan area, moreover, the deformation mode and background had not only certain similitude but also some diversity; (2) The movement field before the earthquake was very ordinal, while after the earthquake, order and disorder existed simultaneously in the displacement field; The displacement quantities of GPS monitoring stations were generally several millimeters; (3) The principal strain field before earthquake was basically tensile in an approximate EW direction and compressive in the SN direction, and tension was predominant.After the earthquake, the principal strain field in the Sichuan area was compressive in the EW direction and tensile in the SN direction, and the compression was predominant. In the Yunnan area, it was tensional in the NE direction and compressive in the NW direction, and tension was predominant; (4) The surficial strain before the earthquake was dominated by superficial expansion, the contractive area being located basically in the east boundary of Sichuan and Yunnan block and its neighborhood. After the earthquake, the Sichuan area was surface contractive (the further north, the greater it was), and south of it was

  9. The west Andaman fault and its influence on the aftershock pattern of the recent megathrust earthquakes in the Andaman-Sumatra region

    Digital Repository Service at National Institute of Oceanography (India)

    KameshRaju, K.A.; Murty, G.P.S.; Amarnath, D.; MohanKumar, M.L.

    Distinctly different rupture patterns of December 2004 and March 2005 megathrust earthquakes occurred in the Andaman-Sumatra region suggest strong influence of tectonic and structural elements. We have analysed the shipboard gravity, bathymetry...

  10. Influence of Viscoelastic Relaxation on Triggered Seismicity due to the March 25, 1990 Nicoya Gulf, Costa Rica Earthquake (United States)

    Elliott, C. E.; Bilek, S. L.; Lithgow-Bertelloni, C.


    The March 1990 Mw=7.0 earthquake off the coast of Nicoya Peninsula, Costa Rica is thought to have been caused by the rupture of a seamount which acted as an asperity [Protti, 1995; Husen, et al., 2002]. An extensive local network recorded the event and the subsequent seismicity in the region, including aftershocks with magnitude greater than 1.5. These earthquakes were located not only in the offshore region near the mainshock, but also approximately 70 km inland, in a region of shallow strike slip faults well away from the interplate thrust. We have examined the static stress changes associated with this event using Coulomb failure criteria and found that most of the subsequent seismicity located near the mainshock occurred in regions of increased Coulomb stress, ranging from 0.4 to 2 bars. Additionally, inland patches of seismicity can be attributed to an increase in Coulomb static stress. Because the stress increases are well within minimum thresholds for stress triggering [Stein, et al., 1992; Taylor, et al., 1996], we suggest that these inland earthquakes were related to the Mw=7.0 earthquake. However, further examination of the catalog of data, provided by OVSICORI, indicates a temporal relationship of stress-triggering of inland events, suggesting possible viscoelastic influences on the triggering. For example, the seismicity rate in one inland region increased from 1.74 events per day for the 84 days prior to the Mw 7.0 earthquake to 6.17 events per day for the 90 days following the event. Both seismic activity and moment release peaked between 70 and 90 days after the March 25 mainshock. Using a 2-D finite element model that is similar in geometry to the simpler elastic model used for the earlier Coloumb modeling, we incorporate viscoelastic relaxation to calculate the stress increases in the inland regions and compare with the results of the elastic version. In addition, we will parameterize the model to include possible material property variations on

  11. Influence of Inhomogeneity on Critical Behavior of Earthquake Model on Random Graph

    Institute of Scientific and Technical Information of China (English)

    ZHANG Duan-Ming; SUN Fan; YU Bo-Ming; PAN Gui-Jun; YIN Yan-Ping; LI Rui; SU Xiang-Ying


    We consider the earthquake model on a random graph. A detailed analysis of the probability distribution of the size of the avalanches will be given. The model with different inhomogeneities is studied in order to compare the critical behavior of different systems. The results indicate that with the increase of the inhomogeneities, the avalanche exponents reduce, i.e., the different numbers of defects cause different critical behaviors of the system. This is virtually ascribed to the dynamical perturbation.

  12. Analysis of prevalence of PTSD and its influencing factors among college students after the Wenchuan earthquake

    Directory of Open Access Journals (Sweden)

    Fu Yan


    Full Text Available Abstract Background This study explored the prevalence and severity of post-traumatic stress disorder (PTSD in college students who lived in earthquake center one year after the Wenchuan earthquake on May 12, 2008, the factors affecting the prevalence of PTSD was also investigated. Methods 2987 students studying at the senior normal school in Tibetan autonomous region which was one of the most devastated regions were selected for this study. The PTSD Checklist-Civilian Version (PCL-C was used as a screening instrument. Results A total of 420 cases (14.1% were diagnosed with PTSD, among which mild, moderate, severe and extreme symptoms were reported in 122, 185, 106 and 7 cases, respectively. The PTSD prevalence in college students lived in the severely affected area was significantly higher than that in the less severe area (P  Conclusions At one year after the earthquake, the PTSD rate in college students in the severely affected area was high. The social support, psychological help and rehabilitation project should be strengthened to improve their ability to cope with the trauma.

  13. Lunisolar tidal and tidal load elastic stress tensor components within the Earth's mantle and their influence on earthquake occurrences (United States)

    Varga, Peter; Grafarend, Erik


    The relationship of earthquakes with the tidal phenomenon since long is a subject of scientific debates and it cannot be regarded as clarified even today. For the purpose of theoretical investigation of this problem a set of second order spheroidal Love-Shida numbers (h(r), k(r), l(r)) and their radial derivatives were determined for the case of a symmetric, non-rotating, elastic, isotropic (SNREI) Earth with a liquid core. By these means, the stress tensor components from the surface to the core-mantle boundary (CMB) were calculated for the case of zonal, tesseral and sectorial tides. Since the tidal potential and its derivatives are coordinate dependent and the zonal, tesseral and sectorial tides have different distributions on and within the Earth, the lunisolar stress cannot influence the break-out of every seismological event in the same degree. A correlation between earthquake energy release and the lunisolar effect can exist in some cases where the seismic area is well determined and has either one seismic source or severe similar ones. Particularly in volcanic areas, where the seismic activity is connected to the volcano's activity, or in the case of some aftershock swarms, significant correlation was found by different authors.


    Directory of Open Access Journals (Sweden)

    Barbara Theilen-Willige


    Full Text Available The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in Valparaiso in Chile in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integrated into a spatial database using Geoinformation Systems (GIS and image processing techniques. The GIS integrated evaluation of satellite imageries, of digital topographic data and of various open-source geodata can contribute to the acquisition of those specific tectonic, geomorphologic/ topographic settings influencing local site conditions in Valparaiso, Chile. Using the weighted overlay techniques in GIS, susceptibility maps were produced indicating areas, where causal factors influencing near- surface earthquake shock occur aggregated. Causal factors (such as unconsolidated sedimentary layers within a basin’s topography, higher groundwater tables, etc. summarizing and interfering each other, rise the susceptibility of soil amplification and of earthquake related secondary effects. This approach was used as well to create a tsunami flooding susceptibility map. LANDSAT Thermal Band 6-imageries were analysed to get information of surface water currents in this area.

  15. The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake

    Institute of Scientific and Technical Information of China (English)

    高孟潭; 金学申; 安卫平; 吕晓健


    The geography information system of the 1303 Hongtong M=8 earthquake has been established. Using the spatial analysis function of GIS, the spatial distribution characteristics of damage and isoseismal of the earthquake are studied. By comparing with the standard earthquake intensity attenuation relationship, the abnormal damage distribution of the earthquake is found, so the relationship of the abnormal distribution with tectonics, site condition and basin are analyzed. In this paper, the influence on the ground motion generated by earthquake source and the underground structures near source also are studied. The influence on seismic zonation, anti-earthquake design, earthquake prediction and earthquake emergency responding produced by the abnormal density distribution are discussed.

  16. Detection of local site conditions influencing earthquake shaking and secondary effects in Southwest-Haiti using remote sensing and GIS-methods

    Directory of Open Access Journals (Sweden)

    B. Theilen-Willige


    Full Text Available The potential contribution of remote sensing and GIS techniques to earthquake hazard analysis was investigated in SW-Haiti in order to improve the systematic, standardized inventory of those areas that are more susceptible to earthquake ground motions or to earthquake related secondary effects such as landslides, liquefaction, soil amplifications, compaction or even tsunami-waves. Geophysical, topographical, geological data and satellite images were collected, processed, and integrated into a spatial database using Geoinformation Systems (GIS and image processing techniques. The GIS integrated evaluation of satellite imageries, of digital topographic data and of various open-source geodata can contribute to the acquisition of those specific tectonic, geomorphologic/topographic settings influencing local site conditions in Haiti and, thus, to a first data base stock. Using the weighted overlay techniques in GIS susceptibility maps were produced indicating areas where causal factors influencing surface-near earthquake shock occur aggregated and interfering each other and, thus, rise the susceptibility to soil amplification. This approach was used as well to create landslide and flooding susceptibility maps.

  17. The influence of critical Moho Reflections on strong ground motions recorded in San Francisco and Oakland during the 1989 Loma Prieta Earthquake (United States)

    Somerville, Paul; Yoshimura, Joanne


    The amplitudes of strong ground motions from the Loma Prieta earthquake recorded in the San Francisco and Oakland areas exceeded the levels predicted by standard empirical attenuation relations. Preliminary analysis of accelerograms having known trigger times strongly suggests that the elevation of ground motion amplitudes in the distance range of approximately 40 to 100 km was due to critical reflections from the base of the crust. These reflections, which are identified on the basis of their arrival times and phase velocity, and by comparison with simulated accelerograms, were large and occurred at relatively close range because of the deep focal depth of the earthquake and the strong velocity gradient at the base of the crust. These motions were further amplified, presumably by impedance contrast effects, at soft soil sites in San Francisco and Oakland. The effect of the critical reflections in amplifying peak accelerations of the Loma Prieta earthquake in the San Francisco and Oakland regions was as large as the effect of soft soil site conditions. Focal depth has an important influence on strong motion attenuation at distances beyond about 40 km, and empirical attenuation relations derived from shallow crustal earthquakes may underpredict the ground motions of deeper crustal events in this distance range. Further analyses using an expanded data base that includes recordings of aftershocks are required to rigorously test the proposed explanation of the ground motions recorded in San Francisco and Oakland, and the conclusions drawn from that explanation.

  18. LOCAL SITE CONDITIONS INFLUENCING EARTHQUAKE INTENSITIES AND SECONDARY COLLATERAL IMPACTS IN THE SEA OF MARMARA REGION - Application of Standardized Remote Sensing and GIS-Methods in Detecting Potentially Vulnerable Areas to Earthquakes, Tsunamis and Other Hazards.

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis


    Full Text Available The destructive earthquake that struck near the Gulf of Izmit along the North Anatolian fault in Northwest Turkey on August 17, 1999, not only generated a local tsunami that was destructive at Golcuk and other coastal cities in the eastern portion of the enclosed Sea of Marmara, but was also responsible for extensive damage from collateral hazards such as subsidence, landslides, ground liquefaction, soil amplifications, compaction and underwater slumping of unconsolidated sediments. This disaster brought attention in the need to identify in this highly populated region, local conditions that enhance earthquake intensities, tsunami run-up and other collateral disaster impacts. The focus of the present study is to illustrate briefly how standardized remote sensing techniques and GIS-methods can help detect areas that are potentially vulnerable, so that disaster mitigation strategies can be implemented more effectively. Apparently, local site conditions exacerbate earthquake intensities and collateral disaster destruction in the Marmara Sea region. However, using remote sensing data, the causal factors can be determined systematically. With proper evaluation of satellite imageries and digital topographic data, specific geomorphologic/topographic settings that enhance disaster impacts can be identified. With a systematic GIS approach - based on Digital Elevation Model (DEM data - geomorphometric parameters that influence the local site conditions can be determined. Digital elevation data, such as SRTM (Shuttle Radar Topography Mission, with 90m spatial resolution and ASTER-data with 30m resolution, interpolated up to 15 m is readily available. Areas with the steepest slopes can be identified from slope gradient maps. Areas with highest curvatures susceptible to landslides can be identified from curvature maps. Coastal areas below the 10 m elevation susceptible to tsunami inundation can be clearly delineated. Height level maps can also help locate

  19. Earthquake Facts (United States)

    Jump to Navigation Earthquake Facts The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, ... we know, there is no such thing as "earthquake weather" . Statistically, there is an equal distribution of ...

  20. Nowcasting earthquakes (United States)

    Rundle, J. B.; Turcotte, D. L.; Donnellan, A.; Grant Ludwig, L.; Luginbuhl, M.; Gong, G.


    Nowcasting is a term originating from economics and finance. It refers to the process of determining the uncertain state of the economy or markets at the current time by indirect means. We apply this idea to seismically active regions, where the goal is to determine the current state of the fault system and its current level of progress through the earthquake cycle. In our implementation of this idea, we use the global catalog of earthquakes, using "small" earthquakes to determine the level of hazard from "large" earthquakes in the region. Our method does not involve any model other than the idea of an earthquake cycle. Rather, we define a specific region and a specific large earthquake magnitude of interest, ensuring that we have enough data to span at least 20 or more large earthquake cycles in the region. We then compute the earthquake potential score (EPS) which is defined as the cumulative probability distribution P(n < n(t)) for the current count n(t) for the small earthquakes in the region. From the count of small earthquakes since the last large earthquake, we determine the value of EPS = P(n < n(t)). EPS is therefore the current level of hazard and assigns a number between 0% and 100% to every region so defined, thus providing a unique measure. Physically, the EPS corresponds to an estimate of the level of progress through the earthquake cycle in the defined region at the current time.

  1. Do Earthquakes Shake Stock Markets? (United States)

    Ferreira, Susana; Karali, Berna


    This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan.

  2. Influence of strong electromagnetic discharges on the dynamics of earthquakes time distribution in the Bishkek test area (Central Asia

    Directory of Open Access Journals (Sweden)

    P. Tosi


    Full Text Available From 08/01/1983 to 28/03/1990, at the Bishkek ElectroMagnetic (EM test site (Northern Tien Shan and Chu Valley area, Central Asia, strong currents, up to 2.5 kA, were released at a 4.5 km long electrical (grounded dipole. This area is seismically active and a catalogue with about 14100 events from 1975 to 1996 has been analyzed. The seismic catalogue was divided into three parts: 1975-1983 first part with no EM experiments, 1983-1990 second part during EM experiments and 1988-1996 after experiments part. Qualitative and quantitative time series non- linear analysis was applied to waiting times of earthquakes to the above three sub catalogue periods. The qualitative approach includes visual inspection of reconstructed phase space, Iterated Function Systems (IFS and Recurrence Quantification Analysis (RQA. The quantitative approach followed correlation integral calculation of reconstructed phase space of waiting time distribution, with noise reduction and surrogate testing methods. Moreover the Lempel- Ziv algorithmic complexity measure (LZC was calculated. General dynamics of earthquakes’ temporal distribution around the test area, reveals properties of low dimensional non linearity. Strong EM discharges lead to the increase in extent of regularity in earthquakes temporal distribution. After cessation of EM experiments the earthquakes’ temporal distribution becomes much more random than before experiments. To avoid non valid conclusions several tests were applied to our data set: differentiation of the time series was applied to check results not affected by non stationarity; the surrogate data approach was followed to reject the hypothesis that dynamics belongs to the colored noise type. Small earthquakes, below completeness threshold, were added to the analysis to check results robustness.

  3. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)


    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  4. Data completeness of the Kumamoto earthquake sequence in the JMA catalog and its influence on the estimation of the ETAS parameters (United States)

    Zhuang, Jiancang; Ogata, Yosihiko; Wang, Ting


    This study investigates the missing data problem in the Japan Meteorological Agency catalog of the Kumamoto aftershock sequence, which occurred since April 15, 2016, in Japan. Based on the assumption that earthquake magnitudes are independent of their occurrence times, we replenish the short-term missing data of small earthquakes by using a bi-scale transformation and study their influence on the maximum likelihood estimate (MLE) of the epidemic-type aftershock sequences (ETAS) parameters by comparing the analysis results from the original and the replenished datasets. The results show that the MLEs of the ETAS parameters vary when this model is fitted to the recorded catalog with different cutoff magnitudes, while those MLEs remain stable for the replenished dataset. Further analysis shows that the seismicity becomes quiescent after the occurrence of the second major shock, which can be regarded as a precursory phenomenon of the occurrence of the subsequent M_J7.3 mainshock. This relative quiescence is demonstrated more clearly by the analysis of the replenished dataset.

  5. Coseismic deformation due to the 2011 Tohoku-oki earthquake: influence of 3-D elastic structure around Japan (United States)

    Hashima, Akinori; Becker, Thorsten W.; Freed, Andrew M.; Sato, Hiroshi; Okaya, David A.


    We investigated the effects of elastic heterogeneity on coseismic deformation associated with the 2011 Tohoku-oki earthquake, Japan, using a 3-D finite element model, incorporating the geometry of regional plate boundaries. Using a forward approach, we computed displacement fields for different elastic models with a given slip distribution. Three main structural models are considered to separate the effects of different kinds of heterogeneity: a homogeneous model, a two-layered model with crust-mantle stratification, and a crust-mantle layered model with a strong subducting slab. We observed two counteracting effects: (1) On large spatial scales, elastic layering with increasing rigidity with depth leads to a decrease in surface displacement. (2) An increase in rigidity from above the slab interface to below causes an increase in surface displacement, because the weaker hanging wall deforms to accommodate coseismic slip. Results for slip inversions associated with the Tohoku-oki earthquake show that slip patterns are modified when comparing homogeneous and heterogeneous models. However, the maximum slip only changes slightly: It increases from 38.5 m in the homogeneous to 39.6 m in the layered case and decreases to 37.3 m when slabs are introduced. Potency, i.e., the product of slip and fault area, changes accordingly. Layering leads to inferred slip distributions that are broader and deeper compared to the homogeneous case, particularly to the south of the overall slip maximum. The introduction of a strong slab leads to a reduction in slip around the slip maximum near the trench. We also find that details of the vertical deformation patterns for heterogeneous models are sensitive to the Poisson's ratio. While elastic heterogeneity does therefore not have a dramatic effect on bulk quantities such as inferred potency, the mechanical response of a layered medium with a slab does lead to a systematically modified slip response, and such effects may bias studies of

  6. The Influence of the Earthquakes on the Compositional Change in Basement Groundwater (on the Example of the South Tatarian Arch) (United States)

    Ibragimov, R.; Plotnikova, I.


    The groundwater composition of deconsolidated zones in the Precambrian crystalline basement of the Volga-Ural anteclise's South Tatarstan Arch was monitored during the period from 1998 to 2003. Chemical and gas compositions of basement waters and fluid levels were monitored in five wells. Other monitoring parameters included total dissolved solids, density and acidity of water and the contents of methane, heavy hydrocarbon gases, hydrogen, helium, carbon dioxide, dissolved organic substances (bitumen carbon) and total nitrogen. In order to study the temporal relationship between variations in water composition and seismic activity, sampling was carried out right after seismic events. Earthquake recording in Tatarstan allowed water sampling to be conducted almost immediately after seismic events. Some regularity in the variation of salt and microelement compositions of water has been outlined. Earthquake frequency has been found to be related to salt and microelement compositions of water. Water samples have shown decreased total dissolved solids content. At the same time, the total iron content decreases and the boron content increases. Peaks of tectonic activity have been found to coincide with increased methane contents. Earthquake peaks have also been found to coincide with maximum hydrogen contents over the whole observation period. A similar relationship has been found for nitrogen Archaean/Proterozoic groundwater monitoring shows changes in total salt, trace-component and gas compositions. These can be related to geological processes of various intensities occurring in the Earth's crust. The total hydrocarbon content of groundwaters has been found to depend on the intensity of geological processes, which indicates the possible entry of additional gas amounts from deconsolidated zones of the crystalline basement into the sedimentary Devonian. It has been established that the most informative indicators of the relationship between groundwater parameters and

  7. Earthquake engineering research: 1982 (United States)

    The Committee on Earthquake Engineering Research addressed two questions: What progress has research produced in earthquake engineering and which elements of the problem should future earthquake engineering pursue. It examined and reported in separate chapters of the report: Applications of Past Research, Assessment of Earthquake Hazard, Earthquake Ground Motion, Soil Mechanics and Earth Structures, Analytical and Experimental Structural Dynamics, Earthquake Design of Structures, Seismic Interaction of Structures and Fluids, Social and Economic Aspects, Earthquake Engineering Education, Research in Japan.

  8. Scaling behavior of the earthquake intertime distribution: influence of large shocks and time scales in the Omori law. (United States)

    Lippiello, Eugenio; Corral, Alvaro; Bottiglieri, Milena; Godano, Cataldo; de Arcangelis, Lucilla


    We present a study of the earthquake intertime distribution D(Δt) for a California catalog in temporal periods of short duration T. We compare experimental results with theoretical predictions and analytical approximate solutions. For the majority of intervals, rescaling intertimes by the average rate leads to collapse of the distributions D(Δt) on a universal curve, whose functional form is well fitted by a Gamma distribution. The remaining intervals, exhibiting a more complex D(Δt), are all characterized by the presence of large shocks. These results can be understood in terms of the relevance of the ratio between the characteristic time c in the Omori law and T: Intervals with Gamma-like behavior are indeed characterized by a vanishing c/T. The above features are also investigated by means of numerical simulations of the Epidemic Type Aftershock Sequence (ETAS) model. This study shows that collapse of D(Δt) is also observed in numerical catalogs; however, the fit with a Gamma distribution is possible only assuming that c depends on the main-shock magnitude m. This result confirms that the dependence of c on m, previously observed for m>6 main shocks, extends also to small m>2.

  9. Connecting slow earthquakes to huge earthquakes. (United States)

    Obara, Kazushige; Kato, Aitaro


    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes.

  10. Connecting slow earthquakes to huge earthquakes (United States)

    Obara, Kazushige; Kato, Aitaro


    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes.

  11. Is Earthquake Triggering Driven by Small Earthquakes?

    CERN Document Server

    Helmstetter, A


    Using a catalog of seismicity for Southern California, we measure how the number of triggered earthquakes increases with the earthquake magnitude. The trade-off between this scaling and the distribution of earthquake magnitudes controls the relative role of small compared to large earthquakes. We show that seismicity triggering is driven by the smallest earthquakes, which trigger fewer aftershocks than larger earthquakes, but which are much more numerous. We propose that the non-trivial scaling of the number of aftershocks emerges from the fractal spatial distribution of aftershocks.

  12. Defeating Earthquakes (United States)

    Stein, R. S.


    The 2004 M=9.2 Sumatra earthquake claimed what seemed an unfathomable 228,000 lives, although because of its size, we could at least assure ourselves that it was an extremely rare event. But in the short space of 8 years, the Sumatra quake no longer looks like an anomaly, and it is no longer even the worst disaster of the Century: 80,000 deaths in the 2005 M=7.6 Pakistan quake; 88,000 deaths in the 2008 M=7.9 Wenchuan, China quake; 316,000 deaths in the M=7.0 Haiti, quake. In each case, poor design and construction were unable to withstand the ferocity of the shaken earth. And this was compounded by inadequate rescue, medical care, and shelter. How could the toll continue to mount despite the advances in our understanding of quake risk? The world's population is flowing into megacities, and many of these migration magnets lie astride the plate boundaries. Caught between these opposing demographic and seismic forces are 50 cities of at least 3 million people threatened by large earthquakes, the targets of chance. What we know for certain is that no one will take protective measures unless they are convinced they are at risk. Furnishing that knowledge is the animating principle of the Global Earthquake Model, launched in 2009. At the very least, everyone should be able to learn what his or her risk is. At the very least, our community owes the world an estimate of that risk. So, first and foremost, GEM seeks to raise quake risk awareness. We have no illusions that maps or models raise awareness; instead, earthquakes do. But when a quake strikes, people need a credible place to go to answer the question, how vulnerable am I, and what can I do about it? The Global Earthquake Model is being built with GEM's new open source engine, OpenQuake. GEM is also assembling the global data sets without which we will never improve our understanding of where, how large, and how frequently earthquakes will strike, what impacts they will have, and how those impacts can be lessened by

  13. Aseismic Slips Preceding Ruptures Assumed for Anomalous Seismicities and Crustal Deformations (United States)

    Ogata, Y.


    If aseismic slips occurs on a fault or its deeper extension, both seismicity and geodetic records around the source should be affected. Such anomalies are revealed to have occurred during the last several years leading up to the October 2004 Chuetsu Earthquake of M6.8, the March 2007 Noto Peninsula Earthquake of M6.9, and the July 2007 Chuetsu-Oki Earthquake of M6.8, which occurred successively in the near-field, central Japan. Seismic zones of negative and positive increments of the Coulomb failure stress, assuming such slips, show seismic quiescence and activation, respectively, relative to the predicted rate by the ETAS model. These are further supported by transient crustal movement around the source preceding the rupture. Namely, time series of the baseline distance records between a numbers of the permanent GPS stations deviated from the predicted trend, with the trend of different slope that is basically consistent with the horizontal displacements of the stations due to the assumed slips. References Ogata, Y. (2007) Seismicity and geodetic anomalies in a wide area preceding the Niigata-Ken-Chuetsu Earthquake of October 23, 2004, central Japan, J. Geophys. Res. 112, in press.

  14. The Christchurch earthquake stroke incidence study. (United States)

    Wu, Teddy Y; Cheung, Jeanette; Cole, David; Fink, John N


    We examined the impact of major earthquakes on acute stroke admissions by a retrospective review of stroke admissions in the 6 weeks following the 4 September 2010 and 22 February 2011 earthquakes. The control period was the corresponding 6 weeks in the previous year. In the 6 weeks following the September 2010 earthquake there were 97 acute stroke admissions, with 79 (81.4%) ischaemic infarctions. This was similar to the 2009 control period which had 104 acute stroke admissions, of whom 80 (76.9%) had ischaemic infarction. In the 6 weeks following the February 2011 earthquake, there were 71 stroke admissions, and 61 (79.2%) were ischaemic infarction. This was less than the 96 strokes (72 [75%] ischaemic infarction) in the corresponding control period. None of the comparisons were statistically significant. There was also no difference in the rate of cardioembolic infarction from atrial fibrillation between the study periods. Patients admitted during the February 2011 earthquake period were less likely to be discharged directly home when compared to the control period (31.2% versus 46.9%, p=0.036). There was no observable trend in the number of weekly stroke admissions between the 2 weeks leading to and 6 weeks following the earthquakes. Our results suggest that severe psychological stress from earthquakes did not influence the subsequent short term risk of acute stroke, but the severity of the earthquake in February 2011 and associated civil structural damages may have influenced the pattern of discharge for stroke patients.

  15. Hurricane Sandy and earthquakes




    Submit for consideration the connection between formation of a hurricane Sandy and earthquakes. As a rule, weather anomalies precede and accompany earthquakes. The hurricane Sandy emerged 2 days prior to strong earthquakes that occurred in the area. And the trajectory of the hurricane Sandy matched the epicenter of the earthquakes. Possibility of early prediction of natural disasters will minimize the moral and material damage.

  16. Influence of epistemic uncertainties on the slip distribution of continental earthquakes: application to the 2009 L'Aquila (Mw6.3) and 2016 Amatrice (Mw6.0) earthquakes, central Italy. (United States)

    Ragon, Théa; Sladen, Anthony; Bletery, Quentin; Simons, Mark; Magnoni, Frederica; Avallone, Antonio; Cavalié, Olivier; Vergnolle, Mathilde


    The increased availability of InSAR observations now allows a quasi-systematic study of the finite-fault slip distribution of continental earthquakes with Mw > 6.0. These data are often complemented by near-fault GPS and seismic records. Despite this deluge of new data, independent studies still frequently result in significantly different inferences of subsurface fault slip. For example, published models for the well-studied 2009 Mw 6.3 earthquake of L'Aquila, Italy, have a maximum coseismic slip patch whose amplitude varies from 0.8 m to 2.3 m, with a centroid depth that varies between 5 and 15 km. Assuming that observational uncertainties are relatively well known (and appropriately accounted for), the discrepancies between inferred source models can be primarily attributed to epistemic uncertainties and the inherent non-uniqueness of inverse problem. Two potentially strong sources of epistemic uncertainties are the poor knowledge of the fault geometry and the elastic properties of the medium around the fault. Here, we explore the contribution of these various effects (non-uniqueness, uncertainties in the elastic properties and fault geometry) on inferences for the L'Aquila, 2009, and Amatrice, 2016, earthquakes. We investigate the non uniqueness of the inverse problem by performing a fully Bayesian analysis, which allows the exploration of the whole solution space of fault-slip models compatible with the data, within the range of both observational and epistemic uncertainties. While the estimation of uncertainties related to elastic properties has been implemented recently on finite-fault slip inversions, the evaluation of fault geometry uncertainty remains unexplored yet and thus could represent a significant issue. The L'Aquila and Amatrice earthquakes share many characteristics, but larger uncertainties yet remain on the geometry of the Amatrice event and on its local elastic structure. This work aims at improving our knowledge of these earthquakes through

  17. Does Casing Material Influence Downhole Accelerometer Recordings? a Controlled Study of Earthquake and Experimental Data Recorded at the NEES@UCSB Wildlife Liquefaction Array (United States)

    Huthsing, D. A.; Seale, S. H.; Steidl, J. H.; Ratzesberger, H.; Hegarty, P.; Nees@Ucsb


    In 2004, NEES@UCSB outfitted the Wildlife Liquefaction Array (WLA) with new instrumentation and initiated an experiment to test whether casing material influences downhole recordings of strong ground motion. Two 5.5m boreholes were drilled meters apart. One of the boreholes was cased with traditional rigid PVC and the other with flexible Corex® drain pipe. Three-component strong-motion accelerometers were installed in both boreholes. Recently we have obtained a unique set of data at WLA that has allowed us to conduct a controlled study. On 15 June 2010, a Mw 5.7 event occurred near Ocotillo, CA, 57 km SW from WLA. A set of 60 aftershocks with M > 3.0 were recorded at WLA with good signal-to-noise ratio. These data are ideal for our study, as the events are approximately co-located relative to the site and they have similar focal mechanisms. We computed frequency spectra for the three components of motion for these events and we computed average spectral ratios between the data in the two boreholes. The spectral ratios are not flat ( = 1): certain frequencies within the range of engineering interest ( f factor of 1.4 is the maximum in this frequency range. In May 2010, NEES@UTexas visited WLA with the vibroseis truck T-Rex. We have performed spectral analysis of borehole recordings from 30 T-Rex pulses with frequencies ranging from 3 to 16 Hz. We present these spectral ratios for comparison with the ones computed from earthquake data.

  18. Relationship between public subsidies and vaccination rates with the 23-valent pneumococcal vaccine in elderly persons, including the influence of the free vaccination campaign after the Great East Japan Earthquake. (United States)

    Naito, Toshio; Matsuda, Naoto; Tanei, Mika; Watanabe, Yukiko; Watanabe, Akira


    Low vaccination rates with pneumococcal vaccine in elderly persons in Japan are thought to be related to low levels of public subsidy. To identify strategies to increase future pneumococcal vaccination rates, we examined the relationship between public subsidies and vaccination rates. We also investigated the influence of free vaccinations after the 2011 Great East Japan Earthquake on vaccination rates in the three Tohoku prefectures of Japan. We surveyed a total of 1742 municipalities in Japan about whether public subsidies were available and their monetary amount. Vaccination rates with the 23-valent pneumococcal vaccine were calculated as the "cumulative amount shipped to each municipality divided by the population aged ≥65 years." There were no subsidies in 773 municipalities (44.4%). In those municipalities with public subsidies, larger subsidies were significantly associated with elevated vaccination rates (p Japan, the vaccination rate was 52.1% in municipalities where the full cost was subsidized. The three prefectures (Iwate, Miyagi, and Fukushima) most affected by the Great East Japan Earthquake ranked as the top three prefectures for vaccination rates in Japan, presumably as a result of the free vaccination campaign for disaster victims. Our findings show that public subsidies play an important role in increasing the vaccination rate. The free vaccinations given to disaster victims after the Great East Japan Earthquake helped to achieve extremely high vaccination rates in the three Tohoku prefectures. We suggest that such public subsidies should be promoted throughout Japan.

  19. Spectral analysis of dike-induced earthquakes in Afar, Ethiopia (United States)

    Tepp, Gabrielle; Ebinger, Cynthia J.; Yun, Sang-Ho


    Shallow dike intrusions may be accompanied by fault slip above the dikes, a superposition which complicates seismic and geodetic data analyses. The diverse volcano-tectonic and low-frequency local earthquakes accompanying the 2005-2010 large-volume dike intrusions in the Dabbahu-Manda Hararo rift (Afar), some with fault displacements of up to 3 m at the surface, provide an opportunity to examine the relations among the earthquakes, dike intrusions, and surface ruptures. We apply the frequency index (FI) method to characterize the spectra of swarm earthquakes from six of the dikes. These earthquakes often have broad spectra with multiple peaks, making the usual peak frequency classification method unreliable. Our results show a general bimodal character with high FI earthquakes associated with deeper dikes (top > 3 km subsurface) and low FI earthquakes associated with shallow dikes, indicating that shallow dikes result in earthquakes with more low-frequency content and larger-amplitude surface waves. Low FI earthquakes are more common during dike emplacement, suggesting that interactions between the dike and faults may lead to lower FI. Taken together, likely source processes for low FI earthquakes are shallow hypocenters (<3 km) possibly with surface rupture, slow rupture velocities, and interactions with dike fluids. Strong site effects also heavily influence the earthquake spectral content. Additionally, our results suggest a continuum of spectral responses, implying either that impulsive volcano-tectonic earthquakes and the unusual, emergent earthquakes have similar source processes or that simple spectral analyses, such as FI, cannot distinguish different source processes.

  20. Earthquake vulnerability evaluation Faizabad district of Kermanshah

    Directory of Open Access Journals (Sweden)

    Saba Naderi


    Full Text Available This paper as examplehas been studied Faizabad district of Kermanshah and to reach its main purpose, which is reducing the damagecaused by the earthquake on the Faizabad district is been providedand in subsidiary purposes part the research is tried identify factors influence in vulnerability earthquakes,pay to provide the factors required; All these factors havean impact on reducing earthquake vulnerability. This data using geological data, soil texture, getting satelliteimages and layering over Arc Gis software identified and for long term periods donepredict using relation kernel PSHA also. In determining the level ofenvironmental risk is to use software crisis. Finally, by recognizing the riskzone, solutions for Faizabad district offered.

  1. Earthquakes: hydrogeochemical precursors (United States)

    Ingebritsen, Steven E.; Manga, Michael


    Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.

  2. Earthquake Damage - General (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An earthquake is the motion or trembling of the ground produced by sudden displacement of rock in the Earth's crust. Earthquakes result from crustal strain,...

  3. Earthquakes in Southern California (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — There have been many earthquake occurrences in Southern California. This set of slides shows earthquake damage from the following events: Imperial Valley, 1979,...

  4. Influence of the impoundment of the Three Gorges Reservoir on the micro-seismicity and the 2013 M5.1 Badong earthquake (Yangtze, China) (United States)

    Zhang, Huai; Cheng, Huihong; Pang, Yajin; Shi, Yaolin; Yuen, David A.


    On December 16, 2013, right after the Three Gorges Reservoir (TGR) reached its highest annual water level, a powerful M5.1 earthquake occurred in Badong County, China's Hubei Province. The epicenter is 5.5 km away from the upstream boundary and 100 km from the dam. Was this earthquake triggered by the impoundment of the TGR, and what are its subsequences? To answer these questions, we constructed a coupled three-dimensional poroelastic finite element model to examine the ground surface deformation, the Coulomb failure stress change (ΔCFS) due to the variation of elastic stress and pore pressure, and the elastic strain energy potential accumulation in the TGR region upon the occurrence of this event. Our calculated maximum surface deformation values beneath the TGR compare well with GPS observations, which validates our numerical model. At the hypocenter of the earthquake, ΔCFS is around 8.0 ∼ 11.0 kPa, revealing that it may be eventually triggered by the impoundment. We also discovered that the total elastic strain energy potential accumulation due to the impounded water load is around 1.7 × 1012 J, merely equivalent to 0.01% of the total energy released by this event, indicating that this earthquake is predominately controlled by the typical regional tectonic settings as well as the weak fault zones, and the reservoir impoundment might only facilitate its procedure or occurrence. Furthermore, the stress level in this region remains high after this earthquake and the subsequent reservoir-triggered micro-seismicity or even bigger event are highly possible.


    Institute of Scientific and Technical Information of China (English)



    Two measures of earthquakes, the seismic moment and the broadband radiated energy, show completely different scaling relations. For shallow earthquakes worldwide from January 1987 to December 1998, the frequency distribution of the seismic moment shows a clear kink between moderate and large earthquakes, as revealed by previous works. But the frequency distribution of the broadband radiated energy shows a single power law, a classical Gutenberg-Richter relation. This inconsistency raises a paradox in the self-organized criticality model of earthquakes.

  6. The desing of an earthquake immune mounting system for a building


    Aldasoro Manero, Nekane


    The focus of this project is to provide the reader with insight into the influence of earthquakes on buildings, and show how, over time, seismologists and engineers have developed designs and insulations to reduce significantly the effects produced by earthquakes. To provide that vision, the project will consist on several parts where different concepts will be explained. • Introduction to earthquakes: To understand the influence of earthquakes on structures, in the first part it wil...

  7. Redefining Earthquakes and the Earthquake Machine (United States)

    Hubenthal, Michael; Braile, Larry; Taber, John


    The Earthquake Machine (EML), a mechanical model of stick-slip fault systems, can increase student engagement and facilitate opportunities to participate in the scientific process. This article introduces the EML model and an activity that challenges ninth-grade students' misconceptions about earthquakes. The activity emphasizes the role of models…

  8. Children's Ideas about Earthquakes (United States)

    Simsek, Canan Lacin


    Earthquake, a natural disaster, is among the fundamental problems of many countries. If people know how to protect themselves from earthquake and arrange their life styles in compliance with this, damage they will suffer will reduce to that extent. In particular, a good training regarding earthquake to be received in primary schools is considered…

  9. Operational earthquake forecasting can enhance earthquake preparedness (United States)

    Jordan, T.H.; Marzocchi, W.; Michael, A.J.; Gerstenberger, M.C.


    We cannot yet predict large earthquakes in the short term with much reliability and skill, but the strong clustering exhibited in seismic sequences tells us that earthquake probabilities are not constant in time; they generally rise and fall over periods of days to years in correlation with nearby seismic activity. Operational earthquake forecasting (OEF) is the dissemination of authoritative information about these time‐dependent probabilities to help communities prepare for potentially destructive earthquakes. The goal of OEF is to inform the decisions that people and organizations must continually make to mitigate seismic risk and prepare for potentially destructive earthquakes on time scales from days to decades. To fulfill this role, OEF must provide a complete description of the seismic hazard—ground‐motion exceedance probabilities as well as short‐term rupture probabilities—in concert with the long‐term forecasts of probabilistic seismic‐hazard analysis (PSHA).

  10. Investigation of atmospheric anomalies associated with Kashmir and Awaran Earthquakes (United States)

    Mahmood, Irfan; Iqbal, Muhammad Farooq; Shahzad, Muhammad Imran; Qaiser, Saddam


    The earthquake precursors' anomalies at diverse elevation ranges over the seismogenic region and prior to the seismic events are perceived using Satellite Remote Sensing (SRS) techniques and reanalysis datasets. In the current research, seismic precursors are obtained by analyzing anomalies in Outgoing Longwave Radiation (OLR), Air Temperature (AT), and Relative Humidity (RH) before the two strong Mw>7 earthquakes in Pakistan occurred on 8th October 2005 in Azad Jammu Kashmir with Mw 7.6, and 24th September 2013 in Awaran, Balochistan with Mw 7.7. Multi-parameter data were computed based on multi-year background data for anomalies computation. Results indicate significant transient variations in observed parameters before the main event. Detailed analysis suggests presence of pre-seismic activities one to three weeks prior to the main earthquake event that vanishes after the event. These anomalies are due to increase in temperature after release of gases and physical and chemical interactions on earth surface before the earthquake. The parameter variations behavior for both Kashmir and Awaran earthquake events are similar to other earthquakes in different regions of the world. This study suggests that energy release is not concentrated to a single fault but instead is released along the fault zone. The influence of earthquake events on lightning were also investigated and it was concluded that there is a significant atmospheric lightning activity after the earthquake suggesting a strong possibility for an earthquake induced thunderstorm. This study is valuable for identifying earthquake precursors especially in earthquake prone areas.

  11. Influence of Earthquake Tsunami Acting on Dynamic Response of Offshore Bridges in Deep Water%地震海啸作用对近海深水桥梁结构动力响应的影响

    Institute of Scientific and Technical Information of China (English)

    黄信; 黄兆纬; 胡雪瀛; 蔡浩良; 齐麟; 刘涛


    It is need to analysis seismic responses of across-sea bridges to ensure safety of bridge structure. Meantime, it is necessary to study the influence of earthquake tsunami action on dynamic responses of bridges in deep water when tsunami is induced because of earthquake action. In this paper, the dynamic responses of offshore bridge in deep water are studied under tsunami action, and earthquake induced hydrodynamic pressure should also be considered based on radiation wave theory. The results indicated that; dynamic responses of bridge in deep water are augmented because of tsunami action, and the influence of tsunami action on seismic response of bridge in deep water is increased with the largen of tsunami wave height. Bridges in deep water will take serious damage and lost bearing capacity when tsunami wave height is more lager. In conclusion, the effect of earthquake tsunami action should be reasonable considered in seismic response analysis of offshore bridges in deep water.%为确保跨海桥梁结构安全,需要进行地震响应分析.同时,由于地震可能引发海啸,有必要分析地震海啸作用对深水桥梁动力响应的影响.本文考虑地震海啸作用,同时采用辐射波浪理论考虑桥墩地震动水压力,对近海深水桥梁结构进行地震响应分析.研究表明:海啸作用增大了桥梁结构的动力响应,其影响随着海啸浪高的增加而增大;海啸浪高较大会导致桥梁结构发生损伤破坏直至丧失承载能力.综上所述,近海深水桥梁结构抗震设计应合理考虑地震海啸作用的影响.

  12. Fluvial Process Influenced by Earthquake Lakes and Restoration of Mountain Rivers%地震堰塞湖对山区河流的影响与综合治理

    Institute of Scientific and Technical Information of China (English)



    On 12 May 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenehuan area, north-western Sichuan province, China. Wenchuan earthquake inevitably impaired the stability of mountains in the course of massive reverse-thrust strike-slip motion in the fault zone. Geohazards were triggered with the types of rock fall, rock avalanches, landslides, debris flows, and earthquake-lakes. In this paper, the types and characteristics of dammed lakes induced by Wenchuan earthquake are analized. The dammed lakes would seriously influence the riv-er sediment transportation, fluvial processes and ecoenvironment. Consequently, the guidline and effective approa-ches for river restoration of dammed lake are susggested, so as to mitigate hazard loss and make the rivers influ-enced by the dammed lake serve us better.%2008年5月12日,中国四川汶川发生里氏8.0级地震,对四川和甘肃的13个县市造成了严重破坏.强烈的主震和余震在地震区造成了大量的滚石、崩塌、滑坡、泥石流、碎屑流等次生山地灾害,大规模滑坡崩塌堵断河道形成堰塞湖,引起山区河流强烈演变.分析了汶川"5·12"地震在四川省境内形成的众多堰塞湖(体)的不同类型、组成特征,提出堰塞体等河道堆积物对河流自然形态、生态环境和人类社会可能存在的影响.针对震后山区河流开发保护与生态环境建设的目标,对堰塞体综合治理提出了具体的指导意见和措施,以便尽可能地避害趋利,有效维护河流的健康.

  13. Earthquake Science: a New Start

    Institute of Scientific and Technical Information of China (English)

    Chen Yun-tai


    @@ Understanding the mechanisms which cause earthquakes and thus earthquake prediction, is inher-ently difficult in comparison to other physical phenom-ena. This is due to the inaccessibility of the Earth's inte-rior, the infrequency of large earthquakes, and the com-plexities of the physical processes involved. Conse-quently, in its broadest sense, earthquake science--the science of studying earthquake phenomena, is a com-prehensive and inter-disciplinary field. The disciplines involved in earthquake science include: traditional seismology, earthquake geodesy, earthquake geology, rock mechanics, complex system theory, and informa-tion and communication technologies related to earth-quake studies.

  14. Wave-equation Based Earthquake Location (United States)

    Tong, P.; Yang, D.; Yang, X.; Chen, J.; Harris, J.


    Precisely locating earthquakes is fundamentally important for studying earthquake physics, fault orientations and Earth's deformation. In industry, accurately determining hypocenters of microseismic events triggered in the course of a hydraulic fracturing treatment can help improve the production of oil and gas from unconventional reservoirs. We develop a novel earthquake location method based on solving full wave equations to accurately locate earthquakes (including microseismic earthquakes) in complex and heterogeneous structures. Traveltime residuals or differential traveltime measurements with the waveform cross-correlation technique are iteratively inverted to obtain the locations of earthquakes. The inversion process involves the computation of the Fréchet derivative with respect to the source (earthquake) location via the interaction between a forward wavefield emitting from the source to the receiver and an adjoint wavefield reversely propagating from the receiver to the source. When there is a source perturbation, the Fréchet derivative not only measures the influence of source location but also the effects of heterogeneity, anisotropy and attenuation of the subsurface structure on the arrival of seismic wave at the receiver. This is essential for the accuracy of earthquake location in complex media. In addition, to reduce the computational cost, we can first assume that seismic wave only propagates in a vertical plane passing through the source and the receiver. The forward wavefield, adjoint wavefield and Fréchet derivative with respect to the source location are all computed in a 2D vertical plane. By transferring the Fréchet derivative along the horizontal direction of the 2D plane into the ones along Latitude and Longitude coordinates or local 3D Cartesian coordinates, the source location can be updated in a 3D geometry. The earthquake location obtained with this combined 2D-3D approach can then be used as the initial location for a true 3D wave

  15. Retrospective Evaluation of Earthquake Forecasts during the 2010-12 Canterbury, New Zealand, Earthquake Sequence (United States)

    Werner, M. J.; Marzocchi, W.; Taroni, M.; Zechar, J. D.; Gerstenberger, M.; Liukis, M.; Rhoades, D. A.; Cattania, C.; Christophersen, A.; Hainzl, S.; Helmstetter, A.; Jimenez, A.; Steacy, S.; Jordan, T. H.


    The M7.1 Darfield, New Zealand (NZ), earthquake triggered a complex earthquake cascade that provides a wealth of new scientific data to study earthquake triggering and the predictive skill of statistical and physics-based forecasting models. To this end, the Collaboratory for the Study of Earthquake Predictability (CSEP) is conducting a retrospective evaluation of over a dozen short-term forecasting models that were developed by groups in New Zealand, Europe and the US. The statistical model group includes variants of the Epidemic-Type Aftershock Sequence (ETAS) model, non-parametric kernel smoothing models, and the Short-Term Earthquake Probabilities (STEP) model. The physics-based model group includes variants of the Coulomb stress triggering hypothesis, which are embedded either in Dieterich's (1994) rate-state formulation or in statistical Omori-Utsu clustering formulations (hybrid models). The goals of the CSEP evaluation are to improve our understanding of the physical mechanisms governing earthquake triggering, to improve short-term earthquake forecasting models and time-dependent hazard assessment for the Canterbury area, and to understand the influence of poor-quality, real-time data on the skill of operational (real-time) forecasts. To assess the latter, we use the earthquake catalog data that the NZ CSEP Testing Center archived in near real-time during the earthquake sequence and compare the predictive skill of models using the archived data as input with the skill attained using the best available data today. We present results of the retrospective model comparison and discuss implications for operational earthquake forecasting.

  16. Encyclopedia of earthquake engineering

    CERN Document Server

    Kougioumtzoglou, Ioannis; Patelli, Edoardo; Au, Siu-Kui


    The Encyclopedia of Earthquake Engineering is designed to be the authoritative and comprehensive reference covering all major aspects of the science of earthquake engineering, specifically focusing on the interaction between earthquakes and infrastructure. The encyclopedia comprises approximately 265 contributions. Since earthquake engineering deals with the interaction between earthquake disturbances and the built infrastructure, the emphasis is on basic design processes important to both non-specialists and engineers so that readers become suitably well-informed without needing to deal with the details of specialist understanding. The content of this encyclopedia provides technically inclined and informed readers about the ways in which earthquakes can affect our infrastructure and how engineers would go about designing against, mitigating and remediating these effects. The coverage ranges from buildings, foundations, underground construction, lifelines and bridges, roads, embankments and slopes. The encycl...

  17. Control of seafloor roughness on earthquake rupture behavior (United States)

    Bilek, Susan L.; Schwartz, Susan Y.; Deshon, Heather R.


    Earthquake rupture complexity is described for three recent large underthrusting earthquakes along the Costa Rican subduction zone, the 1983 Osa, 1990 Nicoya Gulf, and 1999 Quepos events. These earthquakes occurred in regions characterized by distinctly different morphologic features on the subducting plate. The 1990 and 1999 events occurred along linear projections of subducting seamount chains and had fairly simple earthquake rupture histories. Both events are interpreted as failure of the basal contact of closely spaced isolated seamounts acting as asperities. In contrast, the 1983 event occurred along the subducting Cocos Ridge and had a complex rupture history. Comparison of rupture characteristics of these large underthrusting earthquakes with size and location of subducting features provides evidence that seamounts can be subducted to seismogenic depths and that variations in seafloor bathymetry of the subducting plate strongly influence the earthquake rupture process.

  18. Impact of the Wenchuan Earthquake on Tourism in Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    YANG Weiqiong; CHEN Guojie; WANG Daojie


    An intensive earthquake, the Wenchuan Earthquake of 8.0 on the Richter scale, struck western Sichuan, China on May 12, 2008. The earthquake has tremendously affected all industries in the quake-hit areas, with no exception :of the local tourism. The study of the effect of the earthquake on tourism enriches the theory of tourism, and more importantly,it well serves as the foundation for policy making. The objective of this study is to outline for readers the empirical findings on the various ways that the earthquake affected the operations and viability of tourism in the quake-hit areas. This paper is mainly divided into 3 parts. The first part is to discuss the importance of tourism in the quake-hit areas. The second is to analyze the influencing factors of tourism.The third is to assess the impact of the earthquake on tourism in Sichuan in different seasons.

  19. Earthquake at 40 feet (United States)

    Miller, G. J.


    The earthquake that struck the island of Guam on November 1, 1975, at 11:17 a.m had many unique aspects-not the least of which was the experience of an earthquake of 6.25 Richter magnitude while at 40 feet. My wife Bonnie, a fellow diver, Greg Guzman, and I were diving at Gabgab Beach in teh outer harbor of Apra Harbor, engaged in underwater phoyography when the earthquake struck. 

  20. Reduction of earthquake disasters

    Institute of Scientific and Technical Information of China (English)

    陈顒; 陈祺福; 黄静; 徐文立


    The article summarizes the researches on mitigating earthquake disasters of the past four years in China. The studyof earthquake disasters′ quantification shows that the losses increase remarkably when population concentrates inurban area and social wealth increase. The article also summarizes some new trends of studying earthquake disas-ters′ mitigation, which are from seismic hazard to seismic risk, from engineering disaster to social disaster andintroduces the community-centered approach.

  1. 地震应急救援影响因素重要性认识的调查和分析%The Survey and Analysis of the Importance Awareness of the Earthquake Emergency and Rescue Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    邓砚; 苏桂武; 高娜


    The importance analysis of earthquake emergency rescue influencing factors is the basis of earth-quake emergency rescue capabilities assessment,and also one of the important guidance to carry out the earthquake emergency preparedness and improve the capacity of earthquake emergency.Based on the theoretical analysis,lit-erature review and disaster relief cases analysis,the index system of earthquake emergency rescue capabilities is designed,and then take the questionnaire survey method,using the AHP principle,questionnaires are contributed 10 provinces,28 counties,including the department of earthquake,civil affairs and emergency affairs.The results show that,from the perspective of cognition,the infrastructure is the most important factor of the first-level factors. And building aseismic capacity,professional rescue teams and basic medical ability are respectively the most impor-tant factors in the infrastructure aspect and emergency manpower and financial resources.People self-and-commu-nal safe abilities,earthquake relief command coordination agency,acquisition of the disaster,emergency communi-cations equipment,earthquake emergency plan coverage;earthquake emergency drills and training are prominent factors in specialized experience and abilities.Population density,lithology and topographic conditions are the prominent factors in basic environment background.In the comprehensive sequencing,building aseismic capacity, level control hazards,evacuation site area,mobile phone penetration rate,population density,road density,lithol-ogy conditions,professional rescue teams,railway,basic medical ability are the 10 most important factors,which should be the priority.%在理论分析、文献查阅和救灾案例分析的基础上,设计了地震应急救援影响因素指标体系,然后采取问卷调查的手段,利用层次分析法(AHP)原理,设计了影响因素指标重要性的调查问卷,并在全国10省28个县(市)的地震、民政、应

  2. Research on the Influence of the Earthquake in Lushan on the Self-consciousness of Children%芦山地震对儿童自我意识的影响调查研究

    Institute of Scientific and Technical Information of China (English)

    王可晖; 王丽; 石静; 彭怀晴


    Objective:To research the influence of the earthquake on the self-consciousness of local children and analyze the rea-sons, in order to seek effective coping methods. Methods: Using"the scale of children's self-consciousness", the questionnaire and interview survey were carried out on more than 600 students in the earthquake-stricken area, and a course scheme was for-mulated and activities were implemented combined with the ac-tual situation. Result:The mental health level and self-awareness of the local pupils in Lushan were significantly lower than those of other students in the corresponding period. Conclusion:Disas-ters have a great influence on pupils, making their mental health level, sense of safety and self-awareness significantly lower.%目的:调查地震对当地学生儿童自我意识状况的影响,并分析原因,以寻求有效的应对方法。方法:通过《儿童自我意识》量表,对地震灾区600多名小学生进行问卷、访谈调查,并结合实际制定出课程方案,实施活动。结果:芦山当地小学生的心理健康水平、自我意识方面明显低于同期其他地方的学生。结论:灾难对小学生而言有着较大影响,使得他们心理健康水平、安全感、自我认识等方面明显较低。

  3. Earthquakes and Schools (United States)

    National Clearinghouse for Educational Facilities, 2008


    Earthquakes are low-probability, high-consequence events. Though they may occur only once in the life of a school, they can have devastating, irreversible consequences. Moderate earthquakes can cause serious damage to building contents and non-structural building systems, serious injury to students and staff, and disruption of building operations.…

  4. More Earthquake Misery

    Institute of Scientific and Technical Information of China (English)


    Less than four months after the devastation of the Wenchuan earthquake on May 12, another quake brings further death and destruction to southwest China on August 30, a 6.1-magnitude earthquake hit southwest China, the border of Sichuan Province and Yunnan Province. Panzhihua City, Huili County in Sichuan and Yuanmou County and Yongren County in Yunnan were worst hit.

  5. Bam Earthquake in Iran

    CERN Multimedia


    Following their request for help from members of international organisations, the permanent Mission of the Islamic Republic of Iran has given the following bank account number, where you can donate money to help the victims of the Bam earthquake. Re: Bam earthquake 235 - UBS 311264.35L Bubenberg Platz 3001 BERN

  6. Demand surge following earthquakes (United States)

    Olsen, Anna H.


    Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that labor cost increases, rather than the material component, drove the total repair cost increases, and this finding could be extended to earthquakes. A study of past large-scale disasters suggested that there may be additional explanations for demand surge. Two such explanations specific to earthquakes are the exclusion of insurance coverage for earthquake damage and possible concurrent causation of damage from an earthquake followed by fire or tsunami. Additional research into these aspects might provide a better explanation for increased monetary losses after large- vs. small-scale earthquakes.

  7. Modeling earthquake dynamics (United States)

    Charpentier, Arthur; Durand, Marilou


    In this paper, we investigate questions arising in Parsons and Geist (Bull Seismol Soc Am 102:1-11, 2012). Pseudo causal models connecting magnitudes and waiting times are considered, through generalized regression. We do use conditional model (magnitude given previous waiting time, and conversely) as an extension to joint distribution model described in Nikoloulopoulos and Karlis (Environmetrics 19: 251-269, 2008). On the one hand, we fit a Pareto distribution for earthquake magnitudes, where the tail index is a function of waiting time following previous earthquake; on the other hand, waiting times are modeled using a Gamma or a Weibull distribution, where parameters are functions of the magnitude of the previous earthquake. We use those two models, alternatively, to generate the dynamics of earthquake occurrence, and to estimate the probability of occurrence of several earthquakes within a year or a decade.

  8. Phase Transformations and Earthquakes (United States)

    Green, H. W.


    Phase transformations have been cited as responsible for, or at least involved in, "deep" earthquakes for many decades (although the concept of "deep" has varied). In 1945, PW Bridgman laid out in detail the string of events/conditions that would have to be achieved for a solid/solid transformation to lead to a faulting instability, although he expressed pessimism that the full set of requirements would be simultaneously achieved in nature. Raleigh and Paterson (1965) demonstrated faulting during dehydration of serpentine under stress and suggested dehydration embrittlement as the cause of intermediate depth earthquakes. Griggs and Baker (1969) produced a thermal runaway model of a shear zone under constant stress, culminating in melting, and proposed such a runaway as the origin of deep earthquakes. The discovery of Plate Tectonics in the late 1960s established the conditions (subduction) under which Bridgman's requirements for earthquake runaway in a polymorphic transformation could be possible in nature and Green and Burnley (1989) found that instability during the transformation of metastable olivine to spinel. Recent seismic correlation of intermediate-depth-earthquake hypocenters with predicted conditions of dehydration of antigorite serpentine and discovery of metastable olivine in 4 subduction zones, suggests strongly that dehydration embrittlement and transformation-induced faulting are the underlying mechanisms of intermediate and deep earthquakes, respectively. The results of recent high-speed friction experiments and analysis of natural fault zones suggest that it is likely that similar processes occur commonly during many shallow earthquakes after initiation by frictional failure.

  9. Earthquake Disaster Management and Insurance

    Institute of Scientific and Technical Information of China (English)


    As one of the most powerful tools to reduce the earthquake loss, the Earthquake Disaster Management [EDM] and Insurance [EI] have been highlighted and have had a great progress in many countries in recent years. Earthquake disaster management includes a series of contents, such as earthquake hazard and risk analysis, vulnerability analysis of building and infrastructure, earthquake aware training, and building the emergency response system. EI, which has been included in EDM after this practice has been...

  10. Earthquake engineering in Peru (United States)

    Vargas, N.J


    During the last decade, earthquake engineering research in Peru has been carried out at the Catholic University of Peru and at the Universidad Nacional de Ingeniera (UNI). The Geophysical Institute (IGP) under the auspices of the Organization of American States (OAS) has initiated in Peru other efforts in regional seismic hazard assessment programs with direct impact to the earthquake engineering program. Further details on these programs have been reported by L. Ocola in the Earthquake Information Bulletin, January-February 1982, vol. 14, no. 1, pp. 33-38. 

  11. 对影响大学生重游灾后四川的因素的研究%Study on Factors Influencing College Students’Revisiting Sichuan after Earthquake

    Institute of Scientific and Technical Information of China (English)

    吴萍; 黄玉理


    To investigate the influence factors on domestic college students’ perception of tourism image,revisiting willingness and other issues,an empirical study was made after earthquake in Sichuan.The findings show that tourism resources quality,perceived value and overall satisfaction on tourist revisiting intention has significant effect,more importantly,tourism resources quality,reception quality and perceived value have strong influences on tourists’ satisfaction.%为调查地震后大学生旅游者对四川众多旅游目的地的感知形象、重游意愿等问题,通过实证调研发现:旅游目的地资源质量、感知价值和总体满意对大学生旅游者的重游意愿具有显著影响;旅游资源质量、旅游接待质量和感知价值对大学生旅游者的满意度有很强的影响。

  12. Investigation of earthquake mechanisms and their impact on certain basic concepts in earthquake engineering and seismology

    Institute of Scientific and Technical Information of China (English)


    In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medium. The relationship of mantle flow to earthquakes is examined and clarified, and a new model, different from Haskell's, is proposed for the earthquake mechanism. The proposed new model is based on the discovery that two pairs of jump stress and jump velocity will start to act from the fault plane. Records obtained directly from recent earthquakes nearby and right on the fault break show a very large velocity impulse, which verify, indirectly, the new mechanism proposed by the author. Further, at least two physical parameters that characterize the seismic intensity must be specified, because according to the discontinuous (jump) wave theory, at the earthquake source, the stress jump and the velocity jump of particle motion should act simultaneously when a sudden break occurs. The third key parameter is shown to be the break (fracture) propagation speed together with the break plane area. This parameter influences the form of the unloading time function at the source. The maximum seismic stress in and displacement of a building are estimated for two unfavorable combinations of the building and its base ground in terms of their relative rigidity. Finally, it is shown that Bjot's theory of wave propagation in fluid saturated porous media is valid only when fluid flow cannot occur.

  13. 1988 Spitak Earthquake Database (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1988 Spitak Earthquake database is an extensive collection of geophysical and geological data, maps, charts, images and descriptive text pertaining to the...

  14. Earthquake Damage to Schools (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This set of slides graphically illustrates the potential danger that major earthquakes pose to school structures and to the children and adults who happen to be...

  15. Injection-induced earthquakes. (United States)

    Ellsworth, William L


    Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. Injection-induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Earthquakes can be induced as part of the process to stimulate the production from tight shale formations, or by disposal of wastewater associated with stimulation and production. Here, I review recent seismic activity that may be associated with industrial activity, with a focus on the disposal of wastewater by injection in deep wells; assess the scientific understanding of induced earthquakes; and discuss the key scientific challenges to be met for assessing this hazard.

  16. Injection-induced earthquakes (United States)

    Ellsworth, William L.


    Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. Injection-induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Earthquakes can be induced as part of the process to stimulate the production from tight shale formations, or by disposal of wastewater associated with stimulation and production. Here, I review recent seismic activity that may be associated with industrial activity, with a focus on the disposal of wastewater by injection in deep wells; assess the scientific understanding of induced earthquakes; and discuss the key scientific challenges to be met for assessing this hazard.

  17. Charles Darwin's earthquake reports (United States)

    Galiev, Shamil


    As it is the 200th anniversary of Darwin's birth, 2009 has also been marked as 170 years since the publication of his book Journal of Researches. During the voyage Darwin landed at Valdivia and Concepcion, Chile, just before, during, and after a great earthquake, which demolished hundreds of buildings, killing and injuring many people. Land was waved, lifted, and cracked, volcanoes awoke and giant ocean waves attacked the coast. Darwin was the first geologist to observe and describe the effects of the great earthquake during and immediately after. These effects sometimes repeated during severe earthquakes; but great earthquakes, like Chile 1835, and giant earthquakes, like Chile 1960, are rare and remain completely unpredictable. This is one of the few areas of science, where experts remain largely in the dark. Darwin suggested that the effects were a result of ‘ …the rending of strata, at a point not very deep below the surface of the earth…' and ‘…when the crust yields to the tension, caused by its gradual elevation, there is a jar at the moment of rupture, and a greater movement...'. Darwin formulated big ideas about the earth evolution and its dynamics. These ideas set the tone for the tectonic plate theory to come. However, the plate tectonics does not completely explain why earthquakes occur within plates. Darwin emphasised that there are different kinds of earthquakes ‘...I confine the foregoing observations to the earthquakes on the coast of South America, or to similar ones, which seem generally to have been accompanied by elevation of the land. But, as we know that subsidence has gone on in other quarters of the world, fissures must there have been formed, and therefore earthquakes...' (we cite the Darwin's sentences following researchspace. auckland. ac. nz/handle/2292/4474). These thoughts agree with results of the last publications (see Nature 461, 870-872; 636-639 and 462, 42-43; 87-89). About 200 years ago Darwin gave oneself airs by the

  18. Analysis on post-traumatic stress disorder of adolescents and influence fac-tors after earthquake%地震震后青少年创伤后应激障碍与相关影响因素分析

    Institute of Scientific and Technical Information of China (English)



    创伤后应急障碍是地震震后暴露者常见的心理障碍之一,而青少年是易罹患该障碍的高危人群。以文献复习方法归纳地震灾害后青少年创伤后应激障碍的患病情况和影响因素,并展望该问题下一步的研究趋势将有助于为青少年的心理危机干预提供更多的信息。%Post-traumatic stress disorder is one of epidemic psychological barriers in people after the earthquake,and adoles-cents have higher risk in the disorder. With the method of literature review,the research summarized the morbidity,symptom and influ-ence factors of post-traumatic stress disorder,and analyzed the trend for future research,those could contribute to the psychological cri-sis intervention for adolescent.

  19. Earthquake impact scale (United States)

    Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Bausch, D.


    With the advent of the USGS prompt assessment of global earthquakes for response (PAGER) system, which rapidly assesses earthquake impacts, U.S. and international earthquake responders are reconsidering their automatic alert and activation levels and response procedures. To help facilitate rapid and appropriate earthquake response, an Earthquake Impact Scale (EIS) is proposed on the basis of two complementary criteria. On the basis of the estimated cost of damage, one is most suitable for domestic events; the other, on the basis of estimated ranges of fatalities, is generally more appropriate for global events, particularly in developing countries. Simple thresholds, derived from the systematic analysis of past earthquake impact and associated response levels, are quite effective in communicating predicted impact and response needed after an event through alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1,000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses reaching $1M, $100M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness predominate in countries in which local building practices typically lend themselves to high collapse and casualty rates, and these impacts lend to prioritization for international response. In contrast, financial and overall societal impacts often trigger the level of response in regions or countries in which prevalent earthquake resistant construction practices greatly reduce building collapse and resulting fatalities. Any newly devised alert, whether economic- or casualty-based, should be intuitive and consistent with established lexicons and procedures. Useful alerts should

  20. Earthquake and Geothermal Energy

    CERN Document Server

    Kapoor, Surya Prakash


    The origin of earthquake has long been recognized as resulting from strike-slip instability of plate tectonics along the fault lines. Several events of earthquake around the globe have happened which cannot be explained by this theory. In this work we investigated the earthquake data along with other observed facts like heat flow profiles etc... of the Indian subcontinent. In our studies we found a high-quality correlation between the earthquake events, seismic prone zones, heat flow regions and the geothermal hot springs. As a consequence, we proposed a hypothesis which can adequately explain all the earthquake events around the globe as well as the overall geo-dynamics. It is basically the geothermal power, which makes the plates to stand still, strike and slip over. The plates are merely a working solid while the driving force is the geothermal energy. The violent flow and enormous pressure of this power shake the earth along the plate boundaries and also triggers the intra-plate seismicity. In the light o...

  1. Earthquake engineering in China

    Institute of Scientific and Technical Information of China (English)



    The development of earthquake engineering in China is described into three stages.The initial stage in 1950's -1960's was marked with the initiation of this branch of science from its creation in the first national 12-year plan of science andtechnology by specifying earthquake engineering as a branch item and IEM was one participant. The first earthquake zonationmap and the first seismic design code were soon completed and used in engineering design. Site effect on structural design andsite selection were seriously studied. The second stage marked with the occurrence of quite a few strong earthquakes in China,from which many lessons were learned and corresponding considerations were specified in our design codes and followed inconstruction practice. The third stage is a stage of disaster management, which is marked by a series of governmentdocumentations, leading by a national law of the People's Republic of China on the protecting against and mitigating earthquakedisasters adopted at the meeting of the Standing Committee of the National People's Congress of the People's Republic of Chinain 1997, and then followed by some provincial and municipal laws to force the actions outlined in the national law. It may beexpected that our society will be much more safer to resist the attack of future strong earthquakes with less losses. Lastly,possible future developments are also discussed.

  2. Earthquakes, March-April 1989 (United States)

    Person, W.J.


    The first major earthquake (7.0-7.9) of the year hit Mexico on April 25, killing three people and causing some damage. Earthquake-related deaths were also reported from Malawi, China, and New Britain. 

  3. Early earthquakes of the Americas

    Institute of Scientific and Technical Information of China (English)

    Niu Zhijun


    @@ In recent decades the science of seismology,in particular the study of individual earthquakes, has expanded dramatically. A seismologist can look for evidence of past earthquakes in the material remains that have been excavated by archaeologists.

  4. Earthquake Damage to Transportation Systems (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Earthquakes represent one of the most destructive natural hazards known to man. A serious result of large-magnitude earthquakes is the disruption of transportation...

  5. Recurrence Statistics of Great Earthquakes

    CERN Document Server

    Ben-Naim, E; Johnson, P A


    We investigate the sequence of great earthquakes over the past century. To examine whether the earthquake record includes temporal clustering, we identify aftershocks and remove those from the record. We focus on the recurrence time, defined as the time between two consecutive earthquakes. We study the variance in the recurrence time and the maximal recurrence time. Using these quantities, we compare the earthquake record with sequences of random events, generated by numerical simulations, while systematically varying the minimal earthquake magnitude Mmin. Our analysis shows that the earthquake record is consistent with a random process for magnitude thresholds 7.0<=Mmin<=8.3, where the number of events is larger. Interestingly, the earthquake record deviates from a random process at magnitude threshold 8.4<=Mmin<= 8.5, where the number of events is smaller; however, this deviation is not strong enough to conclude that great earthquakes are clustered. Overall, the findings are robust both qualitat...

  6. Dynamic strains for earthquake source characterization (United States)

    Barbour, Andrew; Crowell, Brendan W


    Strainmeters measure elastodynamic deformation associated with earthquakes over a broad frequency band, with detection characteristics that complement traditional instrumentation, but they are commonly used to study slow transient deformation along active faults and at subduction zones, for example. Here, we analyze dynamic strains at Plate Boundary Observatory (PBO) borehole strainmeters (BSM) associated with 146 local and regional earthquakes from 2004–2014, with magnitudes from M 4.5 to 7.2. We find that peak values in seismic strain can be predicted from a general regression against distance and magnitude, with improvements in accuracy gained by accounting for biases associated with site–station effects and source–path effects, the latter exhibiting the strongest influence on the regression coefficients. To account for the influence of these biases in a general way, we include crustal‐type classifications from the CRUST1.0 global velocity model, which demonstrates that high‐frequency strain data from the PBO BSM network carry information on crustal structure and fault mechanics: earthquakes nucleating offshore on the Blanco fracture zone, for example, generate consistently lower dynamic strains than earthquakes around the Sierra Nevada microplate and in the Salton trough. Finally, we test our dynamic strain prediction equations on the 2011 M 9 Tohoku‐Oki earthquake, specifically continuous strain records derived from triangulation of 137 high‐rate Global Navigation Satellite System Earth Observation Network stations in Japan. Moment magnitudes inferred from these data and the strain model are in agreement when Global Positioning System subnetworks are unaffected by spatial aliasing.

  7. Organizational changes at Earthquakes & Volcanoes (United States)

    Gordon, David W.


    Primary responsibility for the preparation of Earthquakes & Volcanoes within the Geological Survey has shifted from the Office of Scientific Publications to the Office of Earthquakes, Volcanoes, and Engineering (OEVE). As a consequence of this reorganization, Henry Spall has stepepd down as Science Editor for Earthquakes & Volcanoes(E&V).

  8. Earthquake scenarios based on lessons from the past (United States)

    Solakov, Dimcho; Simeonova, Stella; Aleksandrova, Irena; Popova, Iliana


    Earthquakes are the most deadly of the natural disasters affecting the human environment; indeed catastrophic earthquakes have marked the whole human history. Global seismic hazard and vulnerability to earthquakes are increasing steadily as urbanization and development occupy more areas that are prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas around the world is often associated with the construction of seismically unsafe buildings and infrastructures, and undertaken with an insufficient knowledge of the regional seismicity peculiarities and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The implementation of the earthquake scenarios into the policies for seismic risk reduction will allow focusing on the prevention of earthquake effects rather than on intervention following the disasters. The territory of Bulgaria (situated in the eastern part of the Balkan Peninsula) represents a typical example of high seismic risk area. Over the centuries, Bulgaria has experienced strong earthquakes. At the beginning of the 20-the century (from 1901 to 1928) five earthquakes with magnitude larger than or equal to MS=7.0 occurred in Bulgaria. However, no such large earthquakes occurred in Bulgaria since 1928, which may induce non-professionals to underestimate the earthquake risk. The 1986 earthquake of magnitude MS=5.7 occurred in the central northern Bulgaria (near the town of Strazhitsa) is the strongest quake after 1928. Moreover, the seismicity of the neighboring countries, like Greece, Turkey, former Yugoslavia and Romania (especially Vrancea-Romania intermediate earthquakes), influences the seismic hazard in Bulgaria. In the present study deterministic scenarios (expressed in seismic intensity) for two Bulgarian cities (Rouse and Plovdiv) are presented. The work on

  9. Quantification of social contributions to earthquake mortality (United States)

    Main, I. G.; NicBhloscaidh, M.; McCloskey, J.; Pelling, M.; Naylor, M.


    Death tolls in earthquakes, which continue to grow rapidly, are the result of complex interactions between physical effects, such as strong shaking, and the resilience of exposed populations and supporting critical infrastructures and institutions. While it is clear that the social context in which the earthquake occurs has a strong effect on the outcome, the influence of this context can only be exposed if we first decouple, as much as we can, the physical causes of mortality from our consideration. (Our modelling assumes that building resilience to shaking is a social factor governed by national wealth, legislation and enforcement and governance leading to reduced levels of corruption.) Here we attempt to remove these causes by statistically modelling published mortality, shaking intensity and population exposure data; unexplained variance from this physical model illuminates the contribution of socio-economic factors to increasing earthquake mortality. We find that this variance partitions countries in terms of basic socio-economic measures and allows the definition of a national vulnerability index identifying both anomalously resilient and anomalously vulnerable countries. In many cases resilience is well correlated with GDP; people in the richest countries are unsurprisingly safe from even the worst shaking. However some low-GDP countries rival even the richest in resilience, showing that relatively low cost interventions can have a positive impact on earthquake resilience and that social learning between these countries might facilitate resilience building in the absence of expensive engineering interventions.

  10. Uncertainty Analysis of Static Coulomb Stress Change Induced by Earthquake A Case Study on the 2008 Ms 8.0 Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)

    Wang Liwei; Chen Qifu


    Static Coulomb stress change induced by earthquake slip is frequently used to explain earthquake activities and aftershock distribution. However, some parameters for the Coulomb stress calculation are unable to be well constrained from laboratory experiments and field observations. Different parameters may directly affect the pattern of static Coulomb stress. The static Coulomb stress changes induced by the Wenchuan earthquake calculated by six research groups are not consistent with each other. To investigate how the parameters affect the calculation results, we change the parameters in turn through modeling and compare the results of different calculation parameters. We find that gravity, position and strike of receiver faults have little influence on coseismic Coulomb stress calculations, but other parameters can change the value and sign of the results in various degrees especially around the earthquake rupture plane. Therefore the uncertainty analysis of static Coulomb stress change induced by earthquake should be taken into consideration in the earthquake hazard analysis.

  11. New characteristics of intensity assessment of Sichuan Lushan "4.20" M s7.0 earthquake (United States)

    Sun, Baitao; Yan, Peilei; Chen, Xiangzhao


    The post-earthquake rapid accurate assessment of macro influence of seismic ground motion is of significance for earthquake emergency relief, post-earthquake reconstruction and scientific research. The seismic intensity distribution map released by the Lushan earthquake field team of the China Earthquake Administration (CEA) five days after the strong earthquake ( M7.0) occurred in Lushan County of Sichuan Ya'an City at 8:02 on April 20, 2013 provides a scientific basis for emergency relief, economic loss assessment and post-earthquake reconstruction. In this paper, the means for blind estimation of macroscopic intensity, field estimation of macro intensity, and review of intensity, as well as corresponding problems are discussed in detail, and the intensity distribution characteristics of the Lushan "4.20" M7.0 earthquake and its influential factors are analyzed, providing a reference for future seismic intensity assessments.

  12. Road Damage Following Earthquake (United States)


    Ground shaking triggered liquefaction in a subsurface layer of water-saturated sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and slit, which moved from right to left towards the Pajaro River. This mode of ground failure, termed lateral spreading, is a principal cause of liquefaction-related earthquake damage caused by the Oct. 17, 1989, Loma Prieta earthquake. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: S.D. Ellen, U.S. Geological Survey

  13. ALMA measures Calama earthquake (United States)

    Brito, R.; Shillue, B.


    On 4 March 2010, the ALMA system response to an extraordinarily large disturbance was measured when a magnitude 6.3 earthquake struck near Calama, Chile, relatively close to the ALMA site. Figures 1 through 4 demonstrate the remarkable performance of the ALMA system to a huge disturbance that was more than 100 times the specification for correction accuracy.

  14. Episodic tremor triggers small earthquakes (United States)

    Balcerak, Ernie


    It has been suggested that episodic tremor and slip (ETS), the weak shaking not associated with measurable earthquakes, could trigger nearby earthquakes. However, this had not been confirmed until recently. Vidale et al. monitored seismicity in the 4-month period around a 16-day episode of episodic tremor and slip in March 2010 in the Cascadia region. They observed five small earthquakes within the subducting slab during the ETS episode. They found that the timing and locations of earthquakes near the tremor suggest that the tremor and earthquakes are related. Furthermore, they observed that the rate of earthquakes across the area was several times higher within 2 days of tremor activity than at other times, adding to evidence of a connection between tremor and earthquakes. (Geochemistry, Geophysics, Geosystems, doi:10.1029/2011GC003559, 2011)

  15. Indonesian Earthquake Decision Support System

    CERN Document Server

    Warnars, Spits


    Earthquake DSS is an information technology environment which can be used by government to sharpen, make faster and better the earthquake mitigation decision. Earthquake DSS can be delivered as E-government which is not only for government itself but in order to guarantee each citizen's rights for education, training and information about earthquake and how to overcome the earthquake. Knowledge can be managed for future use and would become mining by saving and maintain all the data and information about earthquake and earthquake mitigation in Indonesia. Using Web technology will enhance global access and easy to use. Datawarehouse as unNormalized database for multidimensional analysis will speed the query process and increase reports variation. Link with other Disaster DSS in one national disaster DSS, link with other government information system and international will enhance the knowledge and sharpen the reports.

  16. Detailed source process of the 2007 Tocopilla earthquake. (United States)

    Peyrat, S.; Madariaga, R.; Campos, J.; Asch, G.; Favreau, P.; Bernard, P.; Vilotte, J.


    We investigated the detail rupture process of the Tocopilla earthquake (Mw 7.7) of the 14 November 2007 and of the main aftershocks that occurred in the southern part of the North Chile seismic gap using strong motion data. The earthquake happen in the middle of the permanent broad band and strong motion network IPOC newly installed by GFZ and IPGP, and of a digital strong-motion network operated by the University of Chile. The Tocopilla earthquake is the last large thrust subduction earthquake that occurred since the major Iquique 1877 earthquake which produced a destructive tsunami. The Arequipa (2001) and Antofagasta (1995) earthquakes already ruptured the northern and southern parts of the gap, and the intraplate intermediate depth Tarapaca earthquake (2005) may have changed the tectonic loading of this part of the Peru-Chile subduction zone. For large earthquakes, the depth of the seismic rupture is bounded by the depth of the seismogenic zone. What controls the horizontal extent of the rupture for large earthquakes is less clear. Factors that influence the extent of the rupture include fault geometry, variations of material properties and stress heterogeneities inherited from the previous ruptures history. For subduction zones where structures are not well known, what may have stopped the rupture is not obvious. One crucial problem raised by the Tocopilla earthquake is to understand why this earthquake didn't extent further north, and at south, what is the role of the Mejillones peninsula that seems to act as a barrier. The focal mechanism was determined using teleseismic waveforms inversion and with a geodetic analysis (cf. Campos et al.; Bejarpi et al., in the same session). We studied the detailed source process using the strong motion data available. This earthquake ruptured the interplate seismic zone over more than 150 km and generated several large aftershocks, mainly located south of the rupture area. The strong-motion data show clearly two S

  17. "5.12" Great Earthquake Influence the Tourism Development Characteristics of Sichuan Province%“5.12”大地震对四川省旅游业发展的影响特点

    Institute of Scientific and Technical Information of China (English)

    唐弘久; 张捷; 谭如诗


    Based on 12 data reflect tourism development indicators in the period from January 2006 to December 2011 in Sichuan Province, we use principal component loads to get the scores of tourism development, combined the K-means clustering with chart method to analysis the tourism development from macroscopic view; At the same time we use the mean, standard deviation and coefficient of variation to analysis Microscopic change rule of the tourism indicators. The results show that: ① From tourism development score, tourism industry in Sichuan province influenced by the 2008 "5.12" earthquake is quite huge, until 2011 year to return to the level of before earthquakes; ②The international tourism in Sichuan province affected by 2008 "5.12" sudden crisis events more serious;③The domestic tourism in Sichuan Province affected by 2008 "5.12" sudden crises smaller loss, and recover rapidly; ④The international tourism influenced by sudden crises reflect a more sensitive, and the domestic tourism is less affected, with rigid characteristics of its development in the domestic tourism, the reason for this difference is the domestic and foreign markets exist "information asymmetry" phenomenon.%基于12项反映四川省在2006年1月-2011年12月旅游业发展指标数据,利用主成分分析计算期间每月的旅游业发展状况得分,并结合K-均值聚类、图表法研究旅游业发展的宏观变化规律;同时运用均值、标准差、变异系数等方法分析期间旅游指标的微观变化特征.结果表明:①四川省旅游业受2008年“5.12”大地震的影响较大,直到2011年才恢复到震前水平;②四川省的国际旅游业绩受2008年“5.12”突发危机事件消极影响较大;③四川省的国内旅游业绩受2008年“5.12”突发危机事件消极影响较小,恢复较快;④国际旅游对突发危机事件反映比较敏感,而国内旅游受影响较小,其发展带有刚性特点,其原因是国内、国外市场存在“信息不对称”的差异.

  18. Gravitational body forces focus North American intraplate earthquakes (United States)

    Levandowski, Will; Zellman, Mark; Briggs, Rich


    Earthquakes far from tectonic plate boundaries generally exploit ancient faults, but not all intraplate faults are equally active. The North American Great Plains exemplify such intraplate earthquake localization, with both natural and induced seismicity generally clustered in discrete zones. Here we use seismic velocity, gravity and topography to generate a 3D lithospheric density model of the region; subsequent finite-element modelling shows that seismicity focuses in regions of high-gravity-derived deviatoric stress. Furthermore, predicted principal stress directions generally align with those observed independently in earthquake moment tensors and borehole breakouts. Body forces therefore appear to control the state of stress and thus the location and style of intraplate earthquakes in the central United States with no influence from mantle convection or crustal weakness necessary. These results show that mapping where gravitational body forces encourage seismicity is crucial to understanding and appraising intraplate seismic hazard.

  19. Listening to Earthquakes with Infrasound (United States)

    Mucek, A. E.; Langston, C. A.


    A tripartite infrasound array was installed to listen to earthquakes occurring along the Guy-Greenbrier fault in Arkansas. The active earthquake swarm is believed to be caused by deep waste water injections and will allow us to explain the mechanisms causing earthquake "booms" that have been heard during an earthquake. The array has an aperture of 50 meters and is installed next to the X301 seismograph station run by the Center for Earthquake Research and Information (CERI). This arrangement allows simultaneous recording of seismic and acoustic changes from the arrival of an earthquake. Other acoustic and seismic sources that have been found include thunder from thunderstorms, gunshots, quarry explosions and hydraulic fracturing activity from the local gas wells. The duration of the experiment is from the last week of June to the last week of September 2011. During the first month and a half, seven local earthquakes were recorded, along with numerous occurrences of the other infrasound sources. Phase arrival times of the recorded waves allow us to estimate wave slowness and azimuth of infrasound events. Using these two properties, we can determine whether earthquake "booms" occur at a site from the arrival of the P-wave or whether the earthquake "booms" occur elsewhere and travel through the atmosphere. Preliminary results show that the infrasound correlates well to the ground motion during an earthquake for frequencies below 15 Hertz.

  20. 汶川地震伤残人员2年后生存质量及影响因素调查%Survey of qual ity of l ife of the disabled in Wenchuan earthquake after 2 years and its influencing factors

    Institute of Scientific and Technical Information of China (English)

    王定玺; 李小麟; 吴学华; 朱仕超


    Obj ective:To know about the quality of life of the disabled in-Wenchuan earthquake stricken area after 2 years,and to analyze its influen-cing factors,so as to provide evidences for the rehabilitation of disabled per-sons and enhance their quality of life.Methods:After 2 years of Wenchuan earthquake,a total of 172 earthquake disabled persons in heavy disaster area were investigated on their quality of life by cross sectional survey,and the survey tool was concise health survey questionnaire (SF 3 6 ).Results:Af-ter 2 years,all mental health related qualty of life scores of quality of life in 172 cases earthquake disabled persons were lower than that of ordinary residents in Sichuan province;physical function score and general health score were higher than that in 1 year after the earthquake,and after 2 years in addition to the social functions,all dimensions scores were lower than that in 1 year after the earthquake (P<0.05).Single factor analysis was carried out for the 9 factors which may impact the quality of life of the earthquake disabled persons,and the results showed that gender,employ-ment status and disability complications had influence on the quality of life. The quality of life of disabled persons who were male and had disability complications and continued to work was higher than that of disabled per-sons who were female,leisure at home and had disability complications. Multivariate analysis of the quality of life of disabled persons in earthquake showed that the influencing factors of physical health related quality of life of disabled persons in earthquakes were:disability complications,disability complications,per capita monthly income,family structure changes;the in-fluencing factors of the earthquake damage residual mental health related quality of life of disabled persons in earthquakes:disability complications and sex.Conclusion:In 2 years after earthquake the quality of life of the earthquake disabled persons was lower than that of the general

  1. Engineering geological aspect of Gorkha Earthquake 2015, Nepal (United States)

    Adhikari, Basanta Raj; Andermann, Christoff; Cook, Kristen


    Strong shaking by earthquake causes massif landsliding with severe effects on infrastructure and human lives. The distribution of landslides and other hazards are depending on the combination of earthquake and local characteristics which influence the dynamic response of hillslopes. The Himalayas are one of the most active mountain belts with several kilometers of relief and is very prone to catastrophic mass failure. Strong and shallow earthquakes are very common and cause wide spread collapse of hillslopes, increasing the background landslide rate by several magnitude. The Himalaya is facing many small and large earthquakes in the past i.e. earthquakes i.e. Bihar-Nepal earthquake 1934 (Ms 8.2); Large Kangra earthquake of 1905 (Ms 7.8); Gorkha earthquake 2015 (Mw 7.8). The Mw 7.9 Gorkha earthquake has occurred on and around the main Himalayan Thrust with a hypocentral depth of 15 km (GEER 2015) followed by Mw 7.3 aftershock in Kodari causing 8700+ deaths and leaving hundreds of thousands of homeless. Most of the 3000 aftershocks located by National Seismological Center (NSC) within the first 45 days following the Gorkha Earthquake are concentrated in a narrow 40 km-wide band at midcrustal to shallow depth along the strike of the southern slope of the high Himalaya (Adhikari et al. 2015) and the ground shaking was substantially lower in the short-period range than would be expected for and earthquake of this magnitude (Moss et al. 2015). The effect of this earthquake is very unique in affected areas by showing topographic effect, liquefaction and land subsidence. More than 5000 landslides were triggered by this earthquake (Earthquake without Frontiers, 2015). Most of the landslides are shallow and occurred in weathered bedrock and appear to have mobilized primarily as raveling failures, rock slides and rock falls. Majority of landslides are limited to a zone which runs east-west, approximately parallel the lesser and higher Himalaya. There are numerous cracks in

  2. A review of the 2005 Kashmir earthquake-induced landslides; from a remote sensing prospective (United States)

    Shafique, Muhammad; van der Meijde, Mark; Khan, M. Asif


    The 8th October 2005 Kashmir earthquake, in northern Pakistan has triggered thousands of landslides, which was the second major factor in the destruction of the build-up environment, after earthquake-induced ground shaking. Subsequent to the earthquake, several researchers from home and abroad applied a variety of remote sensing techniques, supported with field observations, to develop inventories of the earthquake-triggered landslides, analyzed their spatial distribution and subsequently developed landslide-susceptibility maps. Earthquake causative fault rupture, geology, anthropogenic activities and remote sensing derived topographic attributes were observed to have major influence on the spatial distribution of landslides. These were subsequently used to develop a landslide susceptibility map, thereby demarcating the areas prone to landsliding. Temporal studies monitoring the earthquake-induced landslides shows that the earthquake-induced landslides are stabilized, contrary to earlier belief, directly after the earthquake. The biggest landslide induced dam, as a result of the massive Hattian Bala landslide, is still posing a threat to the surrounding communities. It is observed that remote sensing data is effectively and efficiently used to assess the landslides triggered by the Kashmir earthquake, however, there is still a need of more research to understand the mechanism of intensity and distribution of landslides; and their continuous monitoring using remote sensing data at a regional scale. This paper, provides an overview of remote sensing and GIS applications, for the Kashmir-earthquake triggered landslides, derived outputs and discusses the lessons learnt, advantages, limitations and recommendations for future research.

  3. Pain after earthquake

    Directory of Open Access Journals (Sweden)

    Angeletti Chiara


    Full Text Available Abstract Introduction On 6 April 2009, at 03:32 local time, an Mw 6.3 earthquake hit the Abruzzi region of central Italy causing widespread damage in the City of L Aquila and its nearby villages. The earthquake caused 308 casualties and over 1,500 injuries, displaced more than 25,000 people and induced significant damage to more than 10,000 buildings in the L'Aquila region. Objectives This observational retrospective study evaluated the prevalence and drug treatment of pain in the five weeks following the L'Aquila earthquake (April 6, 2009. Methods 958 triage documents were analysed for patients pain severity, pain type, and treatment efficacy. Results A third of pain patients reported pain with a prevalence of 34.6%. More than half of pain patients reported severe pain (58.8%. Analgesic agents were limited to available drugs: anti-inflammatory agents, paracetamol, and weak opioids. Reduction in verbal numerical pain scores within the first 24 hours after treatment was achieved with the medications at hand. Pain prevalence and characterization exhibited a biphasic pattern with acute pain syndromes owing to trauma occurring in the first 15 days after the earthquake; traumatic pain then decreased and re-surged at around week five, owing to rebuilding efforts. In the second through fourth week, reports of pain occurred mainly owing to relapses of chronic conditions. Conclusions This study indicates that pain is prevalent during natural disasters, may exhibit a discernible pattern over the weeks following the event, and current drug treatments in this region may be adequate for emergency situations.

  4. Earthquake engineering for nuclear facilities

    CERN Document Server

    Kuno, Michiya


    This book is a comprehensive compilation of earthquake- and tsunami-related technologies and knowledge for the design and construction of nuclear facilities. As such, it covers a wide range of fields including civil engineering, architecture, geotechnical engineering, mechanical engineering, and nuclear engineering, for the development of new technologies providing greater resistance against earthquakes and tsunamis. It is crucial both for students of nuclear energy courses and for young engineers in nuclear power generation industries to understand the basics and principles of earthquake- and tsunami-resistant design of nuclear facilities. In Part I, "Seismic Design of Nuclear Power Plants", the design of nuclear power plants to withstand earthquakes and tsunamis is explained, focusing on buildings, equipment's, and civil engineering structures. In Part II, "Basics of Earthquake Engineering", fundamental knowledge of earthquakes and tsunamis as well as the dynamic response of structures and foundation ground...

  5. Earthquake Size Distribution: Power-Law with Exponent Beta = 1/2 ?

    CERN Document Server

    Kagan, Yan Y


    We propose that the widely observed and universal Gutenberg-Richter relation is a mathematical consequence of the critical branching nature of earthquake process in a brittle fracture environment. These arguments, though preliminary, are confirmed by recent investigations of the seismic moment distribution in global earthquake catalogs and by the results on the distribution in crystals of dislocation avalanche sizes. We consider possible systematic and random errors in determining earthquake size, especially its seismic moment. These effects increase the estimate of the parameter beta of the power-law distribution of earthquake sizes. In particular we find that the decrease in relative moment uncertainties with earthquake size causes inflation in the beta-value by about 1-3%. Moreover, earthquake clustering greatly influences the beta-parameter. If clusters (aftershock sequences) are taken as the entity to be studied, then the exponent value for their size distribution would decrease by 5-10%. The complexity ...

  6. Foreshocks of strong earthquakes (United States)

    Guglielmi, A. V.; Sobisevich, L. E.; Sobisevich, A. L.; Lavrov, I. P.


    The specific enhancement of ultra-low-frequency (ULF) electromagnetic oscillations a few hours prior to the strong earthquakes, which was previously mentioned in the literature, motivated us to search for the distinctive features of the mechanical (foreshock) activity of the Earth's crust in the epicentral zones of the future earthquakes. Activation of the foreshocks three hours before the main shock is revealed, which is roughly similar to the enhancement of the specific electromagnetic ULF emission. It is hypothesized that the round-the-world seismic echo signals from the earthquakes, which form the peak of energy release 2 h 50 min before the main events, act as the triggers of the main shocks due to the cumulative action of the surface waves converging to the epicenter. It is established that the frequency of the fluctuations in the foreshock activity decreases at the final stages of the preparation of the main shocks, which probably testifies to the so-called mode softening at the approach of the failure point according to the catastrophe theory.

  7. Influence of Focal Mechanism Types on the Near-field Distribution of Peak Ground Acceleration---Case Study of Tangshan and Wenchuan Earthquake Regions%震源机制类型对近场峰值加速度(PGA)分布的影响--以唐山和汶川震区为例

    Institute of Scientific and Technical Information of China (English)

    孙丽娜; 王晓山; 杨家亮; 张素欣; 刁桂苓; 冯向东


    Peak ground acceleration (PGA)in the near field is associated with earthquake damage, but practical instances of the impact of PGA distribution in the near field of different types of fo-cal mechanism is rarely reported.Using the intensive digital seismic records of the capital circle strong motion network,this paper studies two earthquakes that occurred in April 2003 with an epicenter located in Tangshan.Using data from the strong motion network and the temporary seismic network in Sichuan,Gansu,and Shanxi,it also studies two earthquakes that occurred in July and August 2008 with an epicenter located in Wenchan.By using a function of the thematic map in ArcGIS software,the distribution of both the horizontal synthesis and vertical PGA is es-tablished,obtaining the differences in earthquake PGA distribution in the near field from the faults and strike-slip faults,and the thrust and strike-slip faults.In this paper,we study the impact of different focal mechanisms in the Ninghe and the Wenchuan earthquake on PGA ;the difference in the influence of various focal mechanisms to PGA is especially striking.The results show that this difference is prominent,and that the distribution of major earthquakes PGA is complex in the near field,while that of medium-small earthquakes is also complex.The most crucial place for death and destruction is in the near field.Spectrum analysis established that there are differences in the lower frequencies of seismic waves.Now that there are more buildings and that a greater proportion are multistory and large,the self-vibration period is longer.High values in PGA of nearly vertical strike-slip earthquakes are symmetrically distributed along the fault,while normal faults and reverse faults are concentrated in the hanging wall.The distribution of PGA is complex in the near field,and it is worth noting that the phenomenon of low frequency dip-lip earthquakes is crucial to the input of power and materials in emergency rescue following

  8. Earthquake triggering by slow earthquake propagation: the case of the large 2014 slow slip event in Guerrero, Mexico. (United States)

    Radiguet, M.; Perfettini, H.; Cotte, N.; Gualandi, A.; Kostoglodov, V.; Lhomme, T.; Walpersdorf, A.; Campillo, M.; Valette, B.


    Since their discovery nearly two decades ago, the importance of slow slip events (SSEs) in the processes of strain accommodation in subduction zones has been revealed. Nevertheless, the influence of slow aseismic slip on the nucleation of large earthquakes remains unclear. In this study, we focus on the Guerrero region of the Central American subduction zone in Mexico, where large SSEs have been observed since 1998, with a recurrence period of about 4 years, and produce aseismic slip in the Guerrero seismic gap. We investigate the large 2014 SSE (equivalent Mw=7.7), which initiated in early 2014 and lasted until the end of October 2014. During this time period, the 18 April Papanoa earthquake (Mw7.2) occurred on the western limit of the Guerrero gap. We invert the continuous GPS time series using the PCAIM (Principal Component Analysis Inversion Method) to assess the space and time evolution of slip on the subduction. To focus on the aseismic processes, we correct the cGPS time series from the co-seismic offsets. Our results show that the slow slip event initiated in the Guerrero gap region, as already observed during the previous SSEs. The Mw7.2 Papanoa earthquake occurred on the western limit of the region that was slipping aseismically before the earthquake. After the Papanoa earthquake, the aseismic slip rate increases. This geodetic signal consists of both the ongoing SSE and the postseismic (afterslip) response due to the Papanoa earthquake. The majority of the post-earthquake aseismic slip is concentrated downdip from the main earthquake asperity, but significant slip is also observed in the Guerrero gap region. Compared to previous SSEs in that region, the 2014 SSE produced a larger aseismic slip and the maximum slip is located downdip from the main brittle asperity corresponding to the Papanoa earthquake, a region that was not identified as active during the previous SSEs. Since the Mw 7.2 Papanoa earthquake occurred about 2 months after the onset of the

  9. Influence of Different Emergency Reception and Triage Workflows between Wenchuan and Lushan Earthquakes on the Victim's Length of Stay in Emergency Department%芦山和汶川地震中不同急诊接诊分诊流程对地震伤员急诊滞留时间的影响

    Institute of Scientific and Technical Information of China (English)

    盛洁; 席茜; 白艳; 胡海; 曹钰


    目的 比较在芦山和汶川地震伤员救治中四川大学华西医院两种不同急诊接诊、分诊流程对大规模地震伤员急诊滞留时间的影响.方法 回顾性分析芦山地震后12小时内华西医院急诊科收治的65例伤员的诊治信息及在急诊科滞留时间,与汶川地震时批量伤员急诊滞留时间相对比,分析两种院内急诊接诊、分诊流程对大规模地震伤员急诊滞留时间的影响.结果 芦山地震伤员按接诊、分诊流程在急诊滞留时间中位数为0.51 h,而汶川伤员在急诊滞留时间中位数为2.13h,两者差异有统计学意义(P<0.05).结论 芦山接诊、分诊流程是对汶川地震时的接诊、分诊流程的经验总结和改进,可作为类似灾后批量伤员院内急诊接诊、分诊的参考.%Objective To explore the influence of two emergency reception and triages workflows between Wenchuan and Lushan earthquakes on the victim's length of stay in emergency department of the West China Hospital of Sichuan University.Methods A total of 65 victims admitted in the West China Hospital within 12 hours after Lushan earthquake were retrospectively analyzed,and their diagnosis and treatment information and the length of stay in emergency department were collected and compared with those of the victims in Wenchuan earthquake.Then we analyzed the influence of two emergency reception and triage workflows on the length of stay of the batches of earthquake victims.Results For the Lushan earthquake victims,the median length of stay in the emergency reception and triage workflow was 0.51 hour,while that was 2.13 hours for the Wenchuan earthquake victims,with a significant difference (P<0.05).Conclusion The emergency reception and triage workflow for Lushan earthquake victims is a summarized experience and improvement based on that for Wenchuan earthquake,which can be used as references for treating batches of victims in the emergency department after a disaster.

  10. Earthquake forecasting and its verification

    Directory of Open Access Journals (Sweden)

    J. R. Holliday


    Full Text Available No proven method is currently available for the reliable short time prediction of earthquakes (minutes to months. However, it is possible to make probabilistic hazard assessments for earthquake risk. In this paper we discuss a new approach to earthquake forecasting based on a pattern informatics (PI method which quantifies temporal variations in seismicity. The output, which is based on an association of small earthquakes with future large earthquakes, is a map of areas in a seismogenic region ('hotspots'' where earthquakes are forecast to occur in a future 10-year time span. This approach has been successfully applied to California, to Japan, and on a worldwide basis. Because a sharp decision threshold is used, these forecasts are binary--an earthquake is forecast either to occur or to not occur. The standard approach to the evaluation of a binary forecast is the use of the relative (or receiver operating characteristic (ROC diagram, which is a more restrictive test and less subject to bias than maximum likelihood tests. To test our PI method, we made two types of retrospective forecasts for California. The first is the PI method and the second is a relative intensity (RI forecast based on the hypothesis that future large earthquakes will occur where most smaller earthquakes have occurred in the recent past. While both retrospective forecasts are for the ten year period 1 January 2000 to 31 December 2009, we performed an interim analysis 5 years into the forecast. The PI method out performs the RI method under most circumstances.

  11. Earthquake forecasting: Statistics and Information

    CERN Document Server

    Gertsik, V; Krichevets, A


    We present an axiomatic approach to earthquake forecasting in terms of multi-component random fields on a lattice. This approach provides a method for constructing point estimates and confidence intervals for conditional probabilities of strong earthquakes under conditions on the levels of precursors. Also, it provides an approach for setting multilevel alarm system and hypothesis testing for binary alarms. We use a method of comparison for different earthquake forecasts in terms of the increase of Shannon information. 'Forecasting' and 'prediction' of earthquakes are equivalent in this approach.

  12. 汶川地震安置点灾民抑郁症状及影响因素分析%An analysis on depression and influence factors of victims of Wenchuan earthquake in temporary settlements

    Institute of Scientific and Technical Information of China (English)

    陶炯; 王相兰; 温盛霖; 甘照宇; 李雷俊; 郑俩荣; 单鸿; 张晋碚; 李凌江


    Objective To investigate the symptoms of depression and influence factors of victims of Wen-chuan Earthquake in temporary settlements in the second week.Method A random sample of 225 cases were as-sessed by using Hamilton Rating Scale for Depression (HRSD),Stanford Acute Stress Reaction Questionnaire (SASRQ),Stress Reaction Questionnaire(SRQ) and a self-designed questionnaire.Result 29.33% of the vic-rims had symptoms of depression,11.11% of the victims had suicidal idea.The total score of HRSD(15.67±11.12) had positive correlation with SASRQ (r=0.725,P<0.01) and SRQ (r=0.767,P<0.01).There were statistical differences of the total score of HRSD(F=4.94,P<0.001),anxiety and somatization,blockade,dys-somnia and feeling of despair among 6 age groups by analysis of variance(ANOVA).The children had lower score of HRSD(10.35±9.17) than the adolescent(16.86±11.82),the middle age(19.31±11.94) and the preseni-urn (P<0.05).The dyssomnia of the female victims(3.27±2.25) was worse than the male(2.59±2.27) (t=2.145,P=0.033).The victims who had lost a loved one had higher scores of HRSD(22.82±13.99) than those with property loss only(14.51±10.06) (t=3.308,P=0.002).According to regression model,SRQ,disturbing degree,and SASRQ significantly explained HRSD variance.(R=0.870,F=95.307,P<0.01).Conclusion The victims had obvious symptoms of depression in the second week after the Wenchuan earthquake.The symptoms of depression had positive correlation with the symptoms of acute stress reaction.The symptoms of depression of children were milder.The female victims and the victims who had lost a loved one in the earthquake should be pay more attention to psychological intervention in the after-disaster.%目的 评估汶川地震后第2周安置点灾民的抑郁症状及影响因素.方法 对江油市太平镇安置点灾民随机抽样后,利用汉密尔顿抑郁量表(HRSD)、斯坦福急性应激反应量表(SASRQ)、应激反应问卷(SRQ)及自编调查问卷进行评估,225

  13. Increased stream discharge after the 3 September 2016 Mw 5.8 Pawnee, Oklahoma earthquake (United States)

    Manga, Michael; Wang, Chi-Yuen; Shirzaei, Manoochehr


    Earthquakes influence hydrogeological processes and properties in Earth's crust, some of which affect surface waters. We document increased discharge in a stream after the 3 September 2016 Mw 5.8 earthquake near Pawnee, Oklahoma, an event likely induced by underground wastewater disposal. Discharge increased by an order of magnitude and remained elevated until the change was obscured by rain 1 week later. Given the earthquake magnitude and distance from the stream, by comparison with previous examples of responses to earthquakes, increased discharge after this earthquake is expected. While the mechanism increasing discharge cannot be confirmed, the observations require changes in physical properties of the subsurface. Fluid injection may thus influence hydrogeological properties of shallow groundwater systems and aquifers indirectly by inducing seismicity, if the induced seismic events are large enough.

  14. 1964 Great Alaska Earthquake: a photographic tour of Anchorage, Alaska (United States)

    Thoms, Evan E.; Haeussler, Peter J.; Anderson, Rebecca D.; McGimsey, Robert G.


    On March 27, 1964, at 5:36 p.m., a magnitude 9.2 earthquake, the largest recorded earthquake in U.S. history, struck southcentral Alaska (fig. 1). The Great Alaska Earthquake (also known as the Good Friday Earthquake) occurred at a pivotal time in the history of earth science, and helped lead to the acceptance of plate tectonic theory (Cox, 1973; Brocher and others, 2014). All large subduction zone earthquakes are understood through insights learned from the 1964 event, and observations and interpretations of the earthquake have influenced the design of infrastructure and seismic monitoring systems now in place. The earthquake caused extensive damage across the State, and triggered local tsunamis that devastated the Alaskan towns of Whittier, Valdez, and Seward. In Anchorage, the main cause of damage was ground shaking, which lasted approximately 4.5 minutes. Many buildings could not withstand this motion and were damaged or collapsed even though their foundations remained intact. More significantly, ground shaking triggered a number of landslides along coastal and drainage valley bluffs underlain by the Bootlegger Cove Formation, a composite of facies containing variably mixed gravel, sand, silt, and clay which were deposited over much of upper Cook Inlet during the Late Pleistocene (Ulery and others, 1983). Cyclic (or strain) softening of the more sensitive clay facies caused overlying blocks of soil to slide sideways along surfaces dipping by only a few degrees. This guide is the document version of an interactive web map that was created as part of the commemoration events for the 50th anniversary of the 1964 Great Alaska Earthquake. It is accessible at the U.S. Geological Survey (USGS) Alaska Science Center website: The website features a map display with suggested tour stops in Anchorage, historical photographs taken shortly after the earthquake, repeat photography of selected sites, scanned documents

  15. Make an Earthquake: Ground Shaking! (United States)

    Savasci, Funda


    The main purposes of this activity are to help students explore possible factors affecting the extent of the damage of earthquakes and learn the ways to reduce earthquake damages. In these inquiry-based activities, students have opportunities to develop science process skills and to build an understanding of the relationship among science,…

  16. Heavy tails and earthquake probabilities (United States)

    Ellsworth, William L.


    The 21st century has already seen its share of devastating earthquakes, some of which have been labeled as “unexpected,” at least in the eyes of some seismologists and more than a few journalists. A list of seismological surprises could include the 2004 Sumatra-Andaman Islands; 2008 Wenchuan, China; 2009 Haiti; 2011 Christchurch, New Zealand; and 2011 Tohoku, Japan, earthquakes

  17. Earthquakes Threaten Many American Schools (United States)

    Bailey, Nancy E.


    Millions of U.S. children attend schools that are not safe from earthquakes, even though they are in earthquake-prone zones. Several cities and states have worked to identify and repair unsafe buildings, but many others have done little or nothing to fix the problem. The reasons for ignoring the problem include political and financial ones, but…

  18. Can Satellites Aid Earthquake Predictions?

    Institute of Scientific and Technical Information of China (English)

    John Roach; 李晓辉


    @@ Earthquake prediction is an imprecise science, and to illustrate the point,many experts point to the story of Tangshen①, China. On July 28, 1976, a magnitude② 7. 6 earthquake struck the city of Tangshen, China, without warning. None of the signs of the successful prediction from a year and half earlier were present. An estimated 250,000 people died.

  19. Testing earthquake source inversion methodologies

    KAUST Repository

    Page, Morgan T.


    Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They are also used to provide a rapid assessment of the severity of an earthquake and to estimate losses. However, because of uncertainties in the data, assumed fault geometry and velocity structure, and chosen rupture parameterization, it is not clear which features of these source models are robust. Improved understanding of the uncertainty and reliability of earthquake source inversions will allow the scientific community to use the robust features of kinematic inversions to more thoroughly investigate the complexity of the rupture process and to better constrain other earthquakerelated computations, such as ground motion simulations and static stress change calculations.

  20. The CATDAT damaging earthquakes database

    Directory of Open Access Journals (Sweden)

    J. E. Daniell


    Full Text Available The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes.

    Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon.

    Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected, and economic losses (direct, indirect, aid, and insured.

    Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto ($214 billion USD damage; 2011 HNDECI-adjusted dollars compared to the 2011 Tohoku (>$300 billion USD at time of writing, 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product, exchange rate, wage information, population, HDI (Human Development Index, and insurance information have been collected globally to form comparisons.

    This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global

  1. The 2015 Gorkha Nepal Earthquake: Insights from Earthquake Damage Survey

    Directory of Open Access Journals (Sweden)

    Katsuichiro eGoda


    Full Text Available The 2015 Gorkha Nepal earthquake caused tremendous damage and loss. To gain valuable lessons from this tragic event, an earthquake damage investigation team was dispatched to Nepal from 1 May 2015 to 7 May 2015. A unique aspect of the earthquake damage investigation is that first-hand earthquake damage data were obtained 6 to 11 days after the mainshock. To gain deeper understanding of the observed earthquake damage in Nepal, the paper reviews the seismotectonic setting and regional seismicity in Nepal and analyzes available aftershock data and ground motion data. The earthquake damage observations indicate that the majority of the damaged buildings were stone/brick masonry structures with no seismic detailing, whereas the most of RC buildings were undamaged. This indicates that adequate structural design is the key to reduce the earthquake risk in Nepal. To share the gathered damage data widely, the collected damage data (geo-tagged photos and observation comments are organized using Google Earth and the kmz file is made publicly available.

  2. Remarkable changes in behavior and physiology of laboratory mice after the massive 2011 Tohoku earthquake in Japan.

    Directory of Open Access Journals (Sweden)

    Shuichi Yanai

    Full Text Available A devastating earthquake and tsunami hit Japan on March 11, 2011, followed by several long and intense aftershocks. Laboratory mice housed in the Tokyo, located approximately 330 km south of this earthquake's epicenter, displayed remarkable changes in a variety of behaviors and physiological measures. Although unusual pre-earthquake behaviors have been previously reported in laboratory animals, little is known about behavioral and physiological changes that occur after a great earthquake. In the present study, the effects of Tohoku earthquake on mice behavior were investigated. "Earthquake-experienced" mice displayed a marked increase in food consumption without gaining body weight in response to the earthquake. They also displayed enhanced anxiety, and in a formal fear memory task, showed significantly greater tone- and context-dependent conditioned freezing. Water maze performance of earthquake-experienced mice showed the quicker acquisition of the task, faster swim speed and longer swim distance than the naive mice. Serum corticosterone levels were elevated compared to the naive mice, indicating that the earthquake and aftershocks were stressful for the mice. These results demonstrate that great earthquakes strongly affect mouse behaviors and physiology. Although the effects of a variety of experimental manipulations on mouse behaviors in disease models or in models of higher cognitive functions have been extensively examined, researchers need to be aware how natural phenomena, such as earthquakes and perhaps other natural environmental factors, influence laboratory animal behaviors and physiology.

  3. Remarkable changes in behavior and physiology of laboratory mice after the massive 2011 Tohoku earthquake in Japan. (United States)

    Yanai, Shuichi; Semba, Yuki; Endo, Shogo


    A devastating earthquake and tsunami hit Japan on March 11, 2011, followed by several long and intense aftershocks. Laboratory mice housed in the Tokyo, located approximately 330 km south of this earthquake's epicenter, displayed remarkable changes in a variety of behaviors and physiological measures. Although unusual pre-earthquake behaviors have been previously reported in laboratory animals, little is known about behavioral and physiological changes that occur after a great earthquake. In the present study, the effects of Tohoku earthquake on mice behavior were investigated. "Earthquake-experienced" mice displayed a marked increase in food consumption without gaining body weight in response to the earthquake. They also displayed enhanced anxiety, and in a formal fear memory task, showed significantly greater tone- and context-dependent conditioned freezing. Water maze performance of earthquake-experienced mice showed the quicker acquisition of the task, faster swim speed and longer swim distance than the naive mice. Serum corticosterone levels were elevated compared to the naive mice, indicating that the earthquake and aftershocks were stressful for the mice. These results demonstrate that great earthquakes strongly affect mouse behaviors and physiology. Although the effects of a variety of experimental manipulations on mouse behaviors in disease models or in models of higher cognitive functions have been extensively examined, researchers need to be aware how natural phenomena, such as earthquakes and perhaps other natural environmental factors, influence laboratory animal behaviors and physiology.

  4. New perspective of Earthquake generation in the east margins of Tibet, China (United States)

    Wang, Zhi; Wang, Xuben


    Global seismic waveform inversion can reveal where rupture initiated and how it expanded for the 2013 Ms 7.0 Lushan earthquake, Sichuan province of China. To investigate the generation mechanism of the Lushan earthquake and its relation to the 2008 Wenchuan earthquake (Ms 8.0), we installed 50 temporal seismic stations at the source area following the Lushan earthquake. We also collected crustal stress data along the Longmen-Shan fault zone (LMFZ) to reveal its influence on the Lushan earthquake generation. Our seismic imaging and crustal stress analysis indicates that the Lushan earthquake occurred in a distinct area with high-velocity (Vp, Vs), low-Poisson's ratio (σp and high crustal stress. The high velocity zone at the Lushan source may reflect the metamafic seismogenic layer that enables the accumulation of high crustal stress for large earthquake generation. However, a sharp contrast gap zone with low velocity and high-gσ anomalies is clearly imaged in the upper crust under the conjunction area between the Lushan and Wenchuan earthquakes. Our seismic images indicate that the slow velocity gap zone is associated with fluid-bearing ductile flow from the lower crustal materials of Tibet being pushed into the weakened segment of the LMFZ. Our study suggests that the 2013 Lushan earthquake may have been triggered by the high crustal stress accumulation together with the high coseismic stress increased by the Wenchuan Earthquake in the metamafic seismogenic layer. The contrasting rheological variation in the crust and crustal stress change along the LMFZ controls the rupture processes of the Lushan and Wenchuan earthquakes, as well as the generation of new earthquakes in the future.

  5. Seismic swarm associated with the 2008 eruption of Kasatochi Volcano, Alaska: earthquake locations and source parameters (United States)

    Ruppert, Natalia G.; Prejean, Stephanie G.; Hansen, Roger A.


    An energetic seismic swarm accompanied an eruption of Kasatochi Volcano in the central Aleutian volcanic arc in August of 2008. In retrospect, the first earthquakes in the swarm were detected about 1 month prior to the eruption onset. Activity in the swarm quickly intensified less than 48 h prior to the first large explosion and subsequently subsided with decline of eruptive activity. The largest earthquake measured as moment magnitude 5.8, and a dozen additional earthquakes were larger than magnitude 4. The swarm exhibited both tectonic and volcanic characteristics. Its shear failure earthquake features were b value = 0.9, most earthquakes with impulsive P and S arrivals and higher-frequency content, and earthquake faulting parameters consistent with regional tectonic stresses. Its volcanic or fluid-influenced seismicity features were volcanic tremor, large CLVD components in moment tensor solutions, and increasing magnitudes with time. Earthquake location tests suggest that the earthquakes occurred in a distributed volume elongated in the NS direction either directly under the volcano or within 5-10 km south of it. Following the MW 5.8 event, earthquakes occurred in a new crustal volume slightly east and north of the previous earthquakes. The central Aleutian Arc is a tectonically active region with seismicity occurring in the crusts of the Pacific and North American plates in addition to interplate events. We postulate that the Kasatochi seismic swarm was a manifestation of the complex interaction of tectonic and magmatic processes in the Earth's crust. Although magmatic intrusion triggered the earthquakes in the swarm, the earthquakes failed in context of the regional stress field.

  6. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi


    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  7. Earthquakes: Risk, Monitoring, Notification, and Research (United States)


    far away as Bangladesh , Taiwan, Thailand, and Vietnam. Several large aftershocks have occurred since the main seismic event. The May 12 earthquake...motion of tectonic plates; ! Earthquake geology and paleoseismology: studies of the history, effects, and mechanics of earthquakes; ! Earthquake hazards

  8. Determination of Design Basis Earthquake ground motion

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Muneaki [Japan Atomic Power Co., Tokyo (Japan)


    This paper describes principle of determining of Design Basis Earthquake following the Examination Guide, some examples on actual sites including earthquake sources to be considered, earthquake response spectrum and simulated seismic waves. In sppendix of this paper, furthermore, seismic safety review for N.P.P designed before publication of the Examination Guide was summarized with Check Basis Earthquake. (J.P.N.)

  9. 2010 Chile Earthquake Aftershock Response (United States)

    Barientos, Sergio


    The Mw=8.8 earthquake off the coast of Chile on 27 February 2010 is the 5th largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. The 2010 Chile earthquake ruptured the Concepcion-Constitucion segment of the Nazca/South America plate boundary, south of the Central Chile region and triggered a tsunami along the coast. Following the 2010 earthquake, a very energetic aftershock sequence is being observed in an area that is 600 km along strike from Valparaiso to 150 km south of Concepcion. Within the first three weeks there were over 260 aftershocks with magnitude 5.0 or greater and 18 with magnitude 6.0 or greater (NEIC, USGS). The Concepcion-Constitucion segment lies immediately north of the rupture zone associated with the great magnitude 9.5 Chile earthquake, and south of the 1906 and the 1985 Valparaiso earthquakes. The last great subduction earthquake in the region dates back to the February 1835 event described by Darwin (1871). Since 1835, part of the region was affected in the north by the Talca earthquake in December 1928, interpreted as a shallow dipping thrust event, and by the Chillan earthquake (Mw 7.9, January 1939), a slab-pull intermediate depth earthquake. For the last 30 years, geodetic studies in this area were consistent with a fully coupled elastic loading of the subduction interface at depth; this led to identify the area as a mature seismic gap with potential for an earthquake of magnitude of the order 8.5 or several earthquakes of lesser magnitude. What was less expected was the partial rupturing of the 1985 segment toward north. Today, the 2010 earthquake raises some disturbing questions: Why and how the rupture terminated where it did at the northern end? How did the 2010 earthquake load the adjacent segment to the north and did the 1985 earthquake only partially ruptured the plate interface leaving loaded asperities since

  10. The physics of an earthquake (United States)

    McCloskey, John


    The Sumatra-Andaman earthquake of 26 December 2004 (Boxing Day 2004) and its tsunami will endure in our memories as one of the worst natural disasters of our time. For geophysicists, the scale of the devastation and the likelihood of another equally destructive earthquake set out a series of challenges of how we might use science not only to understand the earthquake and its aftermath but also to help in planning for future earthquakes in the region. In this article a brief account of these efforts is presented. Earthquake prediction is probably impossible, but earth scientists are now able to identify particularly dangerous places for future events by developing an understanding of the physics of stress interaction. Having identified such a dangerous area, a series of numerical Monte Carlo simulations is described which allow us to get an idea of what the most likely consequences of a future earthquake are by modelling the tsunami generated by lots of possible, individually unpredictable, future events. As this article was being written, another earthquake occurred in the region, which had many expected characteristics but was enigmatic in other ways. This has spawned a series of further theories which will contribute to our understanding of this extremely complex problem.

  11. Ionospheric phenomena before strong earthquakes

    Directory of Open Access Journals (Sweden)

    A. S. Silina


    Full Text Available A statistical analysis of several ionospheric parameters before earthquakes with magnitude M > 5.5 located less than 500 km from an ionospheric vertical sounding station is performed. Ionospheric effects preceding "deep" (depth h > 33 km and "crust" (h 33 km earthquakes were analysed separately. Data of nighttime measurements of the critical frequencies foF2 and foEs, the frequency fbEs and Es-spread at the middle latitude station Dushanbe were used. The frequencies foF2 and fbEs are proportional to the square root of the ionization density at heights of 300 km and 100 km, respectively. It is shown that two days before the earthquakes the values of foF2 averaged over the morning hours (00:00 LT–06:00 LT and of fbEs averaged over the nighttime hours (18:00 LT–06:00 LT decrease; the effect is stronger for the "deep" earthquakes. Analysing the coefficient of semitransparency which characterizes the degree of small-scale turbulence, it was shown that this value increases 1–4 days before "crust" earthquakes, and it does not change before "deep" earthquakes. Studying Es-spread which manifests itself as diffuse Es track on ionograms and characterizes the degree of large-scale turbulence, it was found that the number of Es-spread observations increases 1–3 days before the earthquakes; for "deep" earthquakes the effect is more intensive. Thus it may be concluded that different mechanisms of energy transfer from the region of earthquake preparation to the ionosphere occur for "deep" and "crust" events.

  12. Fracking, wastewater disposal, and earthquakes (United States)

    McGarr, Arthur


    In the modern oil and gas industry, fracking of low-permeability reservoirs has resulted in a considerable increase in the production of oil and natural gas, but these fluid-injection activities also can induce earthquakes. Earthquakes induced by fracking are an inevitable consequence of the injection of fluid at high pressure, where the intent is to enhance permeability by creating a system of cracks and fissures that allow hydrocarbons to flow to the borehole. The micro-earthquakes induced during these highly-controlled procedures are generally much too small to be felt at the surface; indeed, the creation or reactivation of a large fault would be contrary to the goal of enhancing permeability evenly throughout the formation. Accordingly, the few case histories for which fracking has resulted in felt earthquakes have been due to unintended fault reactivation. Of greater consequence for inducing earthquakes, modern techniques for producing hydrocarbons, including fracking, have resulted in considerable quantities of coproduced wastewater, primarily formation brines. This wastewater is commonly disposed by injection into deep aquifers having high permeability and porosity. As reported in many case histories, pore pressure increases due to wastewater injection were channeled from the target aquifers into fault zones that were, in effect, lubricated, resulting in earthquake slip. These fault zones are often located in the brittle crystalline rocks in the basement. Magnitudes of earthquakes induced by wastewater disposal often exceed 4, the threshold for structural damage. Even though only a small fraction of disposal wells induce earthquakes large enough to be of concern to the public, there are so many of these wells that this source of seismicity contributes significantly to the seismic hazard in the United States, especially east of the Rocky Mountains where standards of building construction are generally not designed to resist shaking from large earthquakes.

  13. Fractal Models of Earthquake Dynamics

    CERN Document Server

    Bhattacharya, Pathikrit; Kamal,; Samanta, Debashis


    Our understanding of earthquakes is based on the theory of plate tectonics. Earthquake dynamics is the study of the interactions of plates (solid disjoint parts of the lithosphere) which produce seismic activity. Over the last about fifty years many models have come up which try to simulate seismic activity by mimicking plate plate interactions. The validity of a given model is subject to the compliance of the synthetic seismic activity it produces to the well known empirical laws which describe the statistical features of observed seismic activity. Here we present a review of two such models of earthquake dynamics with main focus on a relatively new model namely The Two Fractal Overlap Model.

  14. Earthquakes: Thinking about the unpredictable (United States)

    Geller, Robert J.

    The possibility of predicting earthquakes has been investigated by professionals and amateurs, seismologists and nonseismologists, for over 100 years. More than once, hopes of a workable earthquake prediction scheme have been raised only to be dashed. Such schemes—on some occasions accompanied by claims of an established track record—continue to be proposed, not only by Earth scientists, but also by workers in other fields. The assessment of these claims is not just a scientific or technical question. Public administrators and policy makers must make decisions regarding appropriate action in response to claims that some scheme has a predictive capability, or to specific predictions of imminent earthquakes.

  15. The threat of silent earthquakes (United States)

    Cervelli, Peter


    Not all earthquakes shake the ground. The so-called silent types are forcing scientists to rethink their understanding of the way quake-prone faults behave. In rare instances, silent earthquakes that occur along the flakes of seaside volcanoes may cascade into monstrous landslides that crash into the sea and trigger towering tsunamis. Silent earthquakes that take place within fault zones created by one tectonic plate diving under another may increase the chance of ground-shaking shocks. In other locations, however, silent slip may decrease the likelihood of destructive quakes, because they release stress along faults that might otherwise seem ready to snap.


    Directory of Open Access Journals (Sweden)

    Savaş TOPAL


    Full Text Available Earthquake-induced deformation structures which are called seismites may helpful to clasify the paleoseismic history of a location and to estimate the magnitudes of the potention earthquakes in the future. In this paper, seismites were investigated according to the types formed in deep and shallow lake sediments. Seismites are observed forms of sand dikes, introduced and fractured gravels and pillow structures in shallow lakes and pseudonodules, mushroom-like silts protruding laminites, mixed layers, disturbed varved lamination and loop bedding in deep lake sediments. Earthquake-induced deformation structures, by benefiting from previous studies, were ordered according to their formations and earthquake magnitudes. In this order, the lowest eartquake's record is loop bedding and the highest one is introduced and fractured gravels in lacustrine deposits.

  17. Newmark design spectra considering earthquake magnitudes and site categories (United States)

    Li, Bo; Xie, Wei-Chau; Pandey, M. D.


    Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies and larger amplitudes at low frequencies in comparison with spectra developed by statistical methods. To resolve this problem, this study considers three suites of ground motions recorded at three types of sites. Using these ground motions, influences of the shear-wave velocity, earthquake magnitudes, source-to-site distances on the ratios of ground motion parameters are studied, and spectrum amplification factors are statistically calculated. Spectral bounds for combinations of three site categories and two cases of earthquake magnitudes are estimated. Site design spectrum coefficients for the three site categories considering earthquake magnitudes are established. The problems of Newmark design spectra could be resolved by using the site design spectrum coefficients to modify the spectral values of Newmark design spectra in the acceleration sensitive, velocity sensitive, and displacement sensitive regions.

  18. Deterministic earthquake scenarios for the city of Sofia

    CERN Document Server

    Slavov, S I; Panza, G F; Paskaleva, I; Vaccari, P


    The city of Sofia is exposed to a high seismic risk. Macroseismic intensities in the range of VIII-X (MSK) can be expected in the city. The earthquakes, that can influence the hazard at Sofia, originate either beneath the city or are caused by seismic sources located within a radius of 40km. The city of Sofia is also prone to the remote Vrancea seismic zone in Romania, and particularly vulnerable are the long - period elements of the built environment. The high seismic risk and the lack of instrumental recordings of the regional seismicity makes the use of appropriate credible earthquake scenarios and ground motion modelling approaches for defining the seismic input for the city of Sofia necessary. Complete synthetic seismic signals, due to several earthquake scenarios, were computed along chosen geological profiles crossing the city, applying a hybrid technique, based on the modal summation technique and finite differences. The modelling takes into account simultaneously the geotechnical properties of the si...

  19. Twitter earthquake detection: Earthquake monitoring in a social world (United States)

    Earle, Paul S.; Bowden, Daniel C.; Guy, Michelle R.


    The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets) with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word "earthquake" clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.

  20. Earthquakes in cities revisited

    CERN Document Server

    Wirgin, Armand


    During the last twenty years, a number of publications of theoretical-numerical nature have appeared which come to the apparently-reassuring conclusion that seismic motion on the ground in cities is smaller than what this motion would be in the absence of the buildings (but for the same underground and seismic load). Other than the fact that this finding tells nothing about the motion within the buildings, it must be confronted with the overwhelming empirical evidence (e.g, earthquakes in Sendai (2011), Kathmandu (2015), Tainan City (2016), etc.) that shaking within buildings of a city is often large enough to damage or even destroy these structures. I show, on several examples, that theory can be reconciled with empirical evidence, and suggest that the crucial subject of seismic response in cities is in need of more thorough research.

  1. Earthquake Breccias (Invited) (United States)

    Rowe, C. D.; Melosh, B. L.; Lamothe, K.; Schnitzer, V.; Bate, C.


    Fault breccias are one of the fundamental classes of fault rocks and are observed in many exhumed faults. Some breccias have long been assumed to form co-seismically, but textural or mechanistic evidence for the association with earthquakes has never been documented. For example, at dilational jogs in brittle faults, it is common to find small bodies of chaotic breccia in lenticular or rhombohedral voids bounded by main slip surfaces and linking segments. Sibson interpreted these 'implosion breccias' as evidence of wall rock fracturing during sudden unloading when the dilational jogs open during earthquake slip (Sibson 1985, PAGEOPH v. 124, n. 1, 159-175). However, the role of dynamic fracturing in forming these breccias has not been tested. Moreover, the criteria for identifying implosion breccia have not been defined - do all breccias in dilational jogs or step-overs represent earthquake slip? We are building a database of breccia and microbreccia textures to develop a strictly observational set of criteria for distinction of breccia texture classes. Here, we present observations from the right-lateral Pofadder Shear Zone, South Africa, and use our textural criteria to identify the relative roles of dynamic and quasi-static fracture patterns, comminution/grinding and attrition, hydrothermal alteration, dissolution, and cementation. Nearly 100% exposure in the hyper-arid region south of the Orange River allowed very detailed mapping of frictional fault traces associated with rupture events, containing one or more right-steps in each rupture trace. Fracture patterns characteristic of on- and off-fault damage associated with propagation of dynamic rupture are observed along straight segments of the faults. The wall rock fractures are regularly spaced, begin at the fault trace and propagate at a high angle to the fault, and locally branch into subsidiary fractures before terminating a few cm away. This pattern of fractures has been previously linked to dynamic

  2. Discussion on Earthquake Forecasting and Early Warning

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaodong; Jiang Haikun; Li Mingxiao


    Through analysis of natural and social attributes of earthquake forecasting,the relationship between the natural and social attributes of earthquake forecasting (early warning) has been discussed.Regarding the natural attributes of earthquake forecasting,it only attempts to forecast the magnitude,location and occurrence time of future earthquake based on the aualysis of observational data and relevant theories and taking into consideration the present understanding of seismogeny and earthquake generation.It need not consider the consequences an earthquake forecast involves,and its purpose is to check out the level of scientific understanding of earthquakes.In respect of the social aspect of earthquake forecasting,people also focus on the consequence that the forecasting involves,in addition to its natural aspect,such as the uncertainty of earthquake prediction itself,the impact of earthquake prediction,and the earthquake resistant capability of structures (buildings),lifeline works,etc.In a word,it highlights the risk of earthquake forecasting and tries to mitigate the earthquake hazard as much as possible.In this paper,the authors also discuss the scientific and social challenges faced in earthquake prediction and analyze preliminarily the meanings and content of earthquake early warning.

  3. Sichuan Earthquake in China (United States)


    The Sichuan earthquake in China occurred on May 12, 2008, along faults within the mountains, but near and almost parallel the mountain front, northwest of the city of Chengdu. This major quake caused immediate and severe damage to many villages and cities in the area. Aftershocks pose a continuing danger, but another continuing hazard is the widespread occurrence of landslides that have formed new natural dams and consequently new lakes. These lakes are submerging roads and flooding previously developed lands. But an even greater concern is the possible rapid release of water as the lakes eventually overflow the new dams. The dams are generally composed of disintegrated rock debris that may easily erode, leading to greater release of water, which may then cause faster erosion and an even greater release of water. This possible 'positive feedback' between increasing erosion and increasing water release could result in catastrophic debris flows and/or flooding. The danger is well known to the Chinese earthquake response teams, which have been building spillways over some of the new natural dams. This ASTER image, acquired on June 1, 2008, shows two of the new large landslide dams and lakes upstream from the town of Chi-Kua-Kan at 32o12'N latitude and 104o50'E longitude. Vegetation is green, water is blue, and soil is grayish brown in this enhanced color view. New landslides appear bright off-white. The northern (top) lake is upstream from the southern lake. Close inspection shows a series of much smaller lakes in an elongated 'S' pattern along the original stream path. Note especially the large landslides that created the dams. Some other landslides in this area, such as the large one in the northeast corner of the image, occur only on the mountain slopes, so do not block streams, and do not form lakes.

  4. Extreme value statistics and thermodynamics of earthquakes. Large earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Lavenda, B. [Camerino Univ., Camerino, MC (Italy); Cipollone, E. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). National Centre for Research on Thermodynamics


    A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershocks sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Frechet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions show that self-similar power laws are transformed into non scaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Frechet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same catalogue of Chinese earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Frechet distribution. Earthquake temperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

  5. 抗震救灾官兵生活质量和心理健康状况及影响因素研究%Study on the quality of life and mental health as well as their influence factors in armed officers and soldiers from earthquake relief work

    Institute of Scientific and Technical Information of China (English)

    夜晓亮; 张步振


    目的 了解抗震救灾官兵生活质量和心理健康状况及影响因素.方法 采用随机整群抽样法,应用WHOQOL-BREF和SCL-90量表,对驻昆明某部280名抗震救灾官兵和330名非抗震救灾官兵进行问卷调查.结果 (1)抗震救灾官兵生活质量的生理、心理、社会及环境各领域百分制得分分别为(58.65±15.02)分、(56.88±14.66)分、(63.01±17.92)分、(50.73±15.16)分.除社会领域外,其余三个领域与非抗震救灾官兵之间的差异有统计学意义(P<0.01或P< 0.05).(2)在SCL-90评分中,除躯体化因子分外,抗震救灾官兵在其余各因子分均高于非抗震救灾官兵,且在强迫、抑郁、焦虑、恐怖、偏执和总均分两组之间的差异有统计学意义(P<0.01).(3)民族、籍贯、学历、职别、婚姻状况和是否为独生子女对抗震救灾官兵生活质量和SCL-90评分有不同程度的影响和相关性(P<0.01或P< 0.05).结论 抗震救灾官兵生活质量和心理健康水平均比非抗震救灾官兵差,其影响因素主要有民族、籍贯、学历、职别、婚姻状况和是否为独生子女等.%Objective To understand the quality of life and mental health status and influence factors on armed officers and soldiers from earthquake relief work. Methods sing cluster sampling and WHOQOL-BREF as well as the SCL-90 scale, a questionnaire survey was conducted in 280 officers and soldiers from earthquake relief work and 330 officers and soldiers not from earthquake relief work in Kunming. Results The scores of physiological, psychological, social and environmental domains of QOL among officers and soldiers from earthquake relief work were (58.65±15.02), (56.88±14.66), (63.01±l7.92), and (50.73±15.16), respectively. Statistically significant difference was found in the physiological, psychological, and environmental domains between officers and soldiers from earthquake relief work and those not from earthquake relief work (P<0.01 or P<0

  6. Behavior of Columns During Earthquakes (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The behavior of columns during earthquakes is very important since column failures may lead to additional structural failures and result in total building collapses....

  7. Medical complications associated with earthquakes. (United States)

    Bartels, Susan A; VanRooyen, Michael J


    Major earthquakes are some of the most devastating natural disasters. The epidemiology of earthquake-related injuries and mortality is unique for these disasters. Because earthquakes frequently affect populous urban areas with poor structural standards, they often result in high death rates and mass casualties with many traumatic injuries. These injuries are highly mechanical and often multisystem, requiring intensive curative medical and surgical care at a time when the local and regional medical response capacities have been at least partly disrupted. Many patients surviving blunt and penetrating trauma and crush injuries have subsequent complications that lead to additional morbidity and mortality. Here, we review and summarise earthquake-induced injuries and medical complications affecting major organ systems.

  8. Statistical earthquake focal mechanism forecasts

    CERN Document Server

    Kagan, Yan Y


    Forecasts of the focal mechanisms of future earthquakes are important for seismic hazard estimates and Coulomb stress and other models of earthquake occurrence. Here we report on a high-resolution global forecast of earthquake rate density as a function of location, magnitude, and focal mechanism. In previous publications we reported forecasts of 0.5 degree spatial resolution, covering the latitude range magnitude, and focal mechanism. In previous publications we reported forecasts of 0.5 degree spatial resolution, covering the latitude range from -75 to +75 degrees, based on the Global Central Moment Tensor earthquake catalog. In the new forecasts we've improved the spatial resolution to 0.1 degree and the latitude range from pole to pole. Our focal mechanism estimates require distance-weighted combinations of observed focal mechanisms within 1000 km of each grid point. Simultaneously we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method ...

  9. The Technical Efficiency of Earthquake Medical Rapid Response Teams Following Disasters: The Case of the 2010 Yushu Earthquake in China

    Directory of Open Access Journals (Sweden)

    Xu Liu


    Full Text Available Purpose: Performance assessments of earthquake medical rapid response teams (EMRRTs, particularly the first responders deployed to the hardest hit areas following major earthquakes, should consider efficient and effective use of resources. This study assesses the daily technical efficiency of EMRRTs in the emergency period immediately following the 2010 Yushu earthquake in China. Methods: Data on EMRRTs were obtained from official daily reports of the general headquarters for Yushu earthquake relief, the emergency office of the National Ministry of Health, and the Health Department of Qinghai Province, for a sample of data on 15 EMRRTs over 62 days. Data envelopment analysis was used to examine the technical efficiency in a constant returns to scale model, a variable returns to scale model, and the scale efficiency of EMRRTs. Tobit regression was applied to analyze the effects of corresponding influencing factors. Results: The average technical efficiency scores under constant returns to scale, variable returns to scale, and the scale efficiency scores of the 62 units of analysis were 77.95%, 89.00%, and 87.47%, respectively. The staff-to-bed ratio was significantly related to global technical efficiency. The date of rescue was significantly related to pure technical efficiency. The type of institution to which an EMRRT belonged and the staff-to-bed ratio were significantly related to scale efficiency. Conclusions: This study provides evidence that supports improvements to EMRRT efficiency and serves as a reference for earthquake emergency medical rapid assistance leaders and teams.

  10. A Study on Seismic Hazard Evaluation at the Nagaoka CO2 Storage Site, Japan (United States)

    Horikawa, S.


    RITE carried out the first Japanese pilot-scale CO2 sequestration project from July, 2003 to January, 2005 in Nagaoka City.Supercritical CO2 was injected into an onshore saline aquifer at a depth of 1,100m. CO2 was injected at a rate of 10,400 tonnes. 'Mid Niigata Prefecture Earthquake in 2004' (Mw6.6) and 'The Niigataken Chuetsu-oki Earthquake in 2007' (Mw6.6) occurred during the CO2 injection-test and after the completion of injection-test. Japan is one of the world's major countries with frequent earthquakes.This paper presents a result of seismic response analysis, and reports of seismic hazard evaluation of a reservoir and a caprock. In advance of dynamic response analysis, the earthquake motion recorded on the earth surface assumed the horizontally layer model, and set up the input wave from a basement layer by SHAKE ( = One-Dimensional Seismic Response Analysis). This wave was inputted into the analysis model and the equation of motion was solved using the direct integral calculus by Newmark Beta Method. In Seismic Response Analysis, authors have used Multiple Yield Model (MYM, Iwata, et al., 2013), which can respond also to complicated geological structure. The intensity deformation property of the foundation added the offloading characteristic to the composition rule of Duncan-Chang model in consideration of confining stress dependency, and used for and carried out the nonlinear repetition model. And the deformation characteristic which made it depend on confining stress with the cyclic loadings and un-loadings, and combined Mohr-Coulomb's law as a strength characteristic.The maximum dynamic shearing strain of caprock was generated about 1.1E-04 after the end of an earthquake. Although the dynamic safety factor was 1.925 on the beginning, after the end of an earthquake fell 0.05 point. The dynamic safety factor of reservoir fell to 1.20 from 1.29. As a result of CO2 migration monitoring by the seismic cross-hole tomography, CO2 has stopped in the reservoir

  11. Evaluating the role of large earthquakes on aquifer dynamics using data fusion and knowledge discovery techniques (United States)

    Friedel, Michael; Cox, Simon; Williams, Charles; Holden, Caroline


    Artificial adaptive systems are evaluated for their usefulness in modeling earthquake hydrology of the Canterbury region, NZ. For example, an unsupervised machine-learning technique, self-organizing map, is used to fuse about 200 disparate and sparse data variables (such as, well pressure response, ground acceleration, intensity, shaking, stress and strain; aquifer and well characteristics) associated with the M7.1 Darfield earthquake in 2010 and the M6.3 Christchurch earthquake in 2011. The strength of correlations, determined using cross-component plots, varied between earthquakes with pressure changes more strongly related to dynamic- than static stress-related variables during the M7.1 earthquake, and vice versa during the M6.3. The method highlights the importance of data distribution and that driving mechanisms of earthquake-induced pressure change in the aquifers are not straight forward to interpret. In many cases, data mining revealed that confusion and reduction in correlations are associated with multiple trends in the same plot: one for confined and one for unconfined earthquake response. The autocontractive map and minimum spanning tree techniques are used for grouping variables of similar influence on earthquake hydrology. K-means clustering of neural information identified 5 primary regions influenced by the two earthquakes. The application of genetic doping to a genetic algorithm is used for identifying optimal subsets of variables in formulating predictions of well pressures. Predictions of well pressure changes are compared and contrasted using machine-learning network and symbolic regression models with prediction uncertainty quantified using a leave-one-out cross-validation strategy. These preliminary results provide impetus for subsequent analysis with information from another 100 earthquakes that occurred across the South Island.

  12. Two models for earthquake forerunners (United States)

    Mjachkin, V.I.; Brace, W.F.; Sobolev, G.A.; Dieterich, J.H.


    Similar precursory phenomena have been observed before earthquakes in the United States, the Soviet Union, Japan, and China. Two quite different physical models are used to explain these phenomena. According to a model developed by US seismologists, the so-called dilatancy diffusion model, the earthquake occurs near maximum stress, following a period of dilatant crack expansion. Diffusion of water in and out of the dilatant volume is required to explain the recovery of seismic velocity before the earthquake. According to a model developed by Soviet scientists growth of cracks is also involved but diffusion of water in and out of the focal region is not required. With this model, the earthquake is assumed to occur during a period of falling stress and recovery of velocity here is due to crack closure as stress relaxes. In general, the dilatancy diffusion model gives a peaked precursor form, whereas the dry model gives a bay form, in which recovery is well under way before the earthquake. A number of field observations should help to distinguish between the two models: study of post-earthquake recovery, time variation of stress and pore pressure in the focal region, the occurrence of pre-existing faults, and any changes in direction of precursory phenomena during the anomalous period. ?? 1975 Birkha??user Verlag.

  13. Earthquakes - Volcanoes (Causes and Forecast) (United States)

    Tsiapas, E.


    EARTHQUAKES - VOLCANOES (CAUSES AND FORECAST) ELIAS TSIAPAS RESEARCHER NEA STYRA, EVIA,GREECE TEL.0302224041057 The earthquakes are caused by large quantities of liquids (e.g. H2O, H2S, SO2, ect.) moving through lithosphere and pyrosphere (MOHO discontinuity) till they meet projections (mountains negative projections or projections coming from sinking lithosphere). The liquids are moved from West Eastward carried away by the pyrosphere because of differential speed of rotation of the pyrosphere by the lithosphere. With starting point an earthquake which was noticed at an area and from statistical studies, we know when, where and what rate an earthquake may be, which earthquake is caused by the same quantity of liquids, at the next east region. The forecast of an earthquake ceases to be valid if these components meet a crack in the lithosphere (e.g. limits of lithosphere plates) or a volcano crater. In this case the liquids come out into the atmosphere by the form of gasses carrying small quantities of lava with them (volcano explosion).

  14. Intracontinental basins and strong earthquakes

    Institute of Scientific and Technical Information of China (English)

    邓起东; 高孟潭; 赵新平; 吴建春


    The September 17, 1303 Hongtong M=8 earthquake occurred in Linfen basin of Shanxi down-faulted basin zone. It is the first recorded M=8 earthquake since the Chinese historical seismic records had started and is a great earthquake occurring in the active intracontinental basin. We had held a Meeting of the 700th Anniversary of the 1303 Hongtong M=8 Earthquake in Shanxi and a Symposium on Intracontinental Basins and Strong Earthquakes in Taiyuan City of Shanxi Province on September 17~18, 2003. The articles presented on the symposium discussed the relationships between active intracontinental basins of different properties, developed in different regions, including tensional graben and semi-graben basins in tensile tectonic regions, compression-depression basins and foreland basins in compressive tectonic regions and pull-apart basins in strike-slip tectonic zones, and strong earthquakes in China. In this article we make a brief summary of some problems. The articles published in this special issue are a part of the articles presented on the symposium.

  15. Living with earthquakes - development and usage of earthquake-resistant construction methods in European and Asian Antiquity (United States)

    Kázmér, Miklós; Major, Balázs; Hariyadi, Agus; Pramumijoyo, Subagyo; Ditto Haryana, Yohanes


    outermost layer was treated this way, the core of the shrines was made of simple rectangular blocks. The system resisted both in-plane and out-of-plane shaking quite well, as proven by survival of many shrines for more than a millennium, and by fracturing of blocks instead of displacement during the 2006 Yogyakarta earthquake. Systematic use or disuse of known earthquake-resistant techniques in any one society depends on the perception of earthquake risk and on available financial resources. Earthquake-resistant construction practice is significantly more expensive than regular construction. Perception is influenced mostly by short individual and longer social memory. If earthquake recurrence time is longer than the preservation of social memory, if damaging quakes fade into the past, societies commit the same construction mistakes again and again. Length of the memory is possibly about a generation's lifetime. Events occurring less frequently than 25-30 years can be readily forgotten, and the risk of recurrence considered as negligible, not worth the costs of safe construction practices. (Example of recurring flash floods in Hungary.) Frequent earthquakes maintain safe construction practices, like the Java masonry technique throughout at least two centuries, and like the Fachwerk tradition on Modern Aegean Samos throughout 500 years of political and technological development. (OTKA K67583)

  16. Earthquake Response Modeling for a Parked and Operating Megawatt-Scale Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Prowell, I.; Elgamal, A.; Romanowitz, H.; Duggan, J. E.; Jonkman, J.


    Demand parameters for turbines, such as tower moment demand, are primarily driven by wind excitation and dynamics associated with operation. For that purpose, computational simulation platforms have been developed, such as FAST, maintained by the National Renewable Energy Laboratory (NREL). For seismically active regions, building codes also require the consideration of earthquake loading. Historically, it has been common to use simple building code approaches to estimate the structural demand from earthquake shaking, as an independent loading scenario. Currently, International Electrotechnical Commission (IEC) design requirements include the consideration of earthquake shaking while the turbine is operating. Numerical and analytical tools used to consider earthquake loads for buildings and other static civil structures are not well suited for modeling simultaneous wind and earthquake excitation in conjunction with operational dynamics. Through the addition of seismic loading capabilities to FAST, it is possible to simulate earthquake shaking in the time domain, which allows consideration of non-linear effects such as structural nonlinearities, aerodynamic hysteresis, control system influence, and transients. This paper presents a FAST model of a modern 900-kW wind turbine, which is calibrated based on field vibration measurements. With this calibrated model, both coupled and uncoupled simulations are conducted looking at the structural demand for the turbine tower. Response is compared under the conditions of normal operation and potential emergency shutdown due the earthquake induced vibrations. The results highlight the availability of a numerical tool for conducting such studies, and provide insights into the combined wind-earthquake loading mechanism.

  17. Anomalies of zenith tropospheric delay following the Mw 7.8 Haida Gwaii earthquake (United States)

    Yao, Y. B.; Lei, X. X.; Liu, Q.; He, C. Y.; Zhang, B.; Zhang, L.


    The 2012 Haida Gwaii earthquake was a massive Mw 7.8 earthquake that struck the Queen Carlotte Islands Region on 28 October 2012 (UTC). This study analyzed the variations in zenith tropospheric delay (ZTD) following the Mw 7.8 Haida Gwaii earthquake using near real-time ZTD data collected from eleven stations in the seismic region and the forecast ZTD of ECMWF. A new differential method was used to detect anomalies of ZTD time series. Result showed that obvious ZTD anomalies occurred on the day of the earthquake (day-of-year, doy 302). There were anomalous ZTD variations at eight stations in the post-earthquake period on doy 302, possibly due to the processes of earthquake-generated acoustic waves. Propagation of acoustic waves caused variations of tropospheric parameters (e.g., atmospheric pressure, temperate, and atmosphere density), thus influencing ZTD. Absence of anomalous ZTD variations at the remaining three stations was attributed to the special topographic conditions, i.e., the long epicentral distance and the presence of huge mountains as a natural protective screen. Our work provides new insights to the relationship between of earthquake event and ZTD variation. The proposed differential method is superior to conventional method for detecting specific ZTD anomalies caused by earthquake events.

  18. Twitter earthquake detection: earthquake monitoring in a social world

    Directory of Open Access Journals (Sweden)

    Daniel C. Bowden


    Full Text Available The U.S. Geological Survey (USGS is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word “earthquake” clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.

  19. The Electronic Encyclopedia of Earthquakes (United States)

    Benthien, M.; Marquis, J.; Jordan, T.


    The Electronic Encyclopedia of Earthquakes is a collaborative project of the Southern California Earthquake Center (SCEC), the Consortia of Universities for Research in Earthquake Engineering (CUREE) and the Incorporated Research Institutions for Seismology (IRIS). This digital library organizes earthquake information online as a partner with the NSF-funded National Science, Technology, Engineering and Mathematics (STEM) Digital Library (NSDL) and the Digital Library for Earth System Education (DLESE). When complete, information and resources for over 500 Earth science and engineering topics will be included, with connections to curricular materials useful for teaching Earth Science, engineering, physics and mathematics. Although conceived primarily as an educational resource, the Encyclopedia is also a valuable portal to anyone seeking up-to-date earthquake information and authoritative technical sources. "E3" is a unique collaboration among earthquake scientists and engineers to articulate and document a common knowledge base with a shared terminology and conceptual framework. It is a platform for cross-training scientists and engineers in these complementary fields and will provide a basis for sustained communication and resource-building between major education and outreach activities. For example, the E3 collaborating organizations have leadership roles in the two largest earthquake engineering and earth science projects ever sponsored by NSF: the George E. Brown Network for Earthquake Engineering Simulation (CUREE) and the EarthScope Project (IRIS and SCEC). The E3 vocabulary and definitions are also being connected to a formal ontology under development by the SCEC/ITR project for knowledge management within the SCEC Collaboratory. The E3 development system is now fully operational, 165 entries are in the pipeline, and the development teams are capable of producing 20 new, fully reviewed encyclopedia entries each month. Over the next two years teams will

  20. Evidence for Ancient Mesoamerican Earthquakes (United States)

    Kovach, R. L.; Garcia, B.


    Evidence for past earthquake damage at Mesoamerican ruins is often overlooked because of the invasive effects of tropical vegetation and is usually not considered as a casual factor when restoration and reconstruction of many archaeological sites are undertaken. Yet the proximity of many ruins to zones of seismic activity would argue otherwise. Clues as to the types of damage which should be soughtwere offered in September 1999 when the M = 7.5 Oaxaca earthquake struck the ruins of Monte Alban, Mexico, where archaeological renovations were underway. More than 20 structures were damaged, 5 of them seriously. Damage features noted were walls out of plumb, fractures in walls, floors, basal platforms and tableros, toppling of columns, and deformation, settling and tumbling of walls. A Modified Mercalli Intensity of VII (ground accelerations 18-34 %b) occurred at the site. Within the diffuse landward extension of the Caribbean plate boundary zone M = 7+ earthquakes occur with repeat times of hundreds of years arguing that many Maya sites were subjected to earthquakes. Damage to re-erected and reinforced stelae, walls, and buildings were witnessed at Quirigua, Guatemala, during an expedition underway when then 1976 M = 7.5 Guatemala earthquake on the Motagua fault struck. Excavations also revealed evidence (domestic pttery vessels and skeleton of a child crushed under fallen walls) of an ancient earthquake occurring about the teim of the demise and abandonment of Quirigua in the late 9th century. Striking evidence for sudden earthquake building collapse at the end of the Mayan Classic Period ~A.D. 889 was found at Benque Viejo (Xunantunich), Belize, located 210 north of Quirigua. It is argued that a M = 7.5 to 7.9 earthquake at the end of the Maya Classic period centered in the vicinity of the Chixoy-Polochic and Motagua fault zones cound have produced the contemporaneous earthquake damage to the above sites. As a consequences this earthquake may have accelerated the

  1. A Prospect of Earthquake Prediction Research

    CERN Document Server

    Ogata, Yosihiko


    Earthquakes occur because of abrupt slips on faults due to accumulated stress in the Earth's crust. Because most of these faults and their mechanisms are not readily apparent, deterministic earthquake prediction is difficult. For effective prediction, complex conditions and uncertain elements must be considered, which necessitates stochastic prediction. In particular, a large amount of uncertainty lies in identifying whether abnormal phenomena are precursors to large earthquakes, as well as in assigning urgency to the earthquake. Any discovery of potentially useful information for earthquake prediction is incomplete unless quantitative modeling of risk is considered. Therefore, this manuscript describes the prospect of earthquake predictability research to realize practical operational forecasting in the near future.

  2. Comparison of two large earthquakes: the 2008 Sichuan Earthquake and the 2011 East Japan Earthquake. (United States)

    Otani, Yuki; Ando, Takayuki; Atobe, Kaori; Haiden, Akina; Kao, Sheng-Yuan; Saito, Kohei; Shimanuki, Marie; Yoshimoto, Norifumi; Fukunaga, Koichi


    Between August 15th and 19th, 2011, eight 5th-year medical students from the Keio University School of Medicine had the opportunity to visit the Peking University School of Medicine and hold a discussion session titled "What is the most effective way to educate people for survival in an acute disaster situation (before the mental health care stage)?" During the session, we discussed the following six points: basic information regarding the Sichuan Earthquake and the East Japan Earthquake, differences in preparedness for earthquakes, government actions, acceptance of medical rescue teams, earthquake-induced secondary effects, and media restrictions. Although comparison of the two earthquakes was not simple, we concluded that three major points should be emphasized to facilitate the most effective course of disaster planning and action. First, all relevant agencies should formulate emergency plans and should supply information regarding the emergency to the general public and health professionals on a normal basis. Second, each citizen should be educated and trained in how to minimize the risks from earthquake-induced secondary effects. Finally, the central government should establish a single headquarters responsible for command, control, and coordination during a natural disaster emergency and should centralize all powers in this single authority. We hope this discussion may be of some use in future natural disasters in China, Japan, and worldwide.

  3. Earthquake Source and Ground Motion Characteristics of Great Kanto Earthquakes (United States)

    Somerville, P. G.; Sato, T.; Wald, D. J.; Graves, R. W.; Dan, K.


    This paper describes the derivation of a rupture model of the 1923 Kanto earthquake, and the estimation of ground motions that occurred during that earthquake and that might occur during future great Kanto earthquakes. The rupture model was derived from the joint inversion of geodetic and teleseismic data. The leveling and triangulation data place strong constraints on the distribution and orientation of slip on the fault. The most concentrated slip is in the shallow central and western part of the fault. The location of the hypocenter on the western part of the fault gives rise to strong near fault rupture directivity effects, which are largest toward the east in the Boso Peninsula. To estimate the ground motions caused by this earthquake, we first calibrated 1D and 3D wave propagation path effects using the Odawara earthquake of 5 August 1990 (M 5.1), the first earthquake larger than M 5 in the last 60 years near the hypocenter of the 1923 Kanto earthquake. The simulation of the moderate-sized Odawara earthquake demonstrates that the 3D velocity model works quite well at reproducing the recorded long-period (T > 3.33 sec) strong motions, including basin-generated surface waves, for a number of sites located throughout the Kanto basin region. Using this validated 3D model along with the rupture model described above, we simulated the long-period (T > 4 sec) ground motions in this region for the 1923 Kanto earthquake. The largest ground motions occur east of the epicenter along the central and southern part of the Boso Peninsula. These large motions arise from strong rupture directivity effects and are comprised of relatively simple, source-controlled pulses with a dominant period of about 10 sec. Other rupture models and hypocenter locations generally produce smaller long period ground motion levels in this region that those of the 1923 event. North of the epicentral region, in the Tokyo area, 3D basin-generated phases are quite significant, and these phases

  4. Earthquake, GIS and multimedia. The 1883 Casamicciola earthquake

    Directory of Open Access Journals (Sweden)

    M. Rebuffat


    Full Text Available A series of multimedia monographs concerning the main seismic events that have affected the Italian territory are in the process of being produced for the Documental Integrated Multimedia Project (DIMP started by the Italian National Seismic Survey (NSS. The purpose of the project is to reconstruct the historical record of earthquakes and promote an earthquake public education. Producing the monographs. developed in ARC INFO and working in UNIX. involved designing a special filing and management methodology to integrate heterogeneous information (images, papers, cartographies, etc.. This paper describes the possibilities of a GIS (Geographic Information System in the filing and management of documental information. As an example we present the first monograph on the 1883 Casamicciola earthquake. on the island of Ischia (Campania, Italy. This earthquake is particularly interesting for the following reasons: I historical-cultural context (first destructive seismic event after the unification of Italy; 2 its features (volcanic earthquake; 3 the socioeconomic consequences caused at such an important seaside resort.

  5. Extreme value statistics and thermodynamics of earthquakes: large earthquakes

    Directory of Open Access Journals (Sweden)

    B. H. Lavenda


    Full Text Available A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershock sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Fréchet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions shows that self-similar power laws are transformed into nonscaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Fréchet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same Catalogue of Chinese Earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Fréchet distribution. Earthquaketemperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

  6. Intra-day response of foreign exchange markets after the Tohoku-Oki earthquake (United States)

    Nakano, Shuhei; Hirata, Yoshito; Iwayama, Koji; Aihara, Kazuyuki


    Although an economy is influenced by a natural disaster, the market response to the disaster during the first 24 hours is not clearly understood. Here we show that an earthquake quickly causes temporal changes in a foreign exchange market by examining the case of the Tohoku-Oki earthquake. Recurrence plots and statistical change point detection independently show that the United States dollar-Japanese yen market responded to the earthquake activity without delay and with the delay of about 2 minutes, respectively. These findings support that the efficient market hypothesis nearly holds now in the time scale of minutes.

  7. Connectivity of earthquake-triggered landslides with the fluvial network: Implications for landslide sediment transport after the 2008 Wenchuan earthquake (United States)

    Li, Gen; West, A. Joshua; Densmore, Alexander L.; Hammond, Douglas E.; Jin, Zhangdong; Zhang, Fei; Wang, Jin; Hilton, Robert G.


    Evaluating the influence of earthquakes on erosion, landscape evolution, and sediment-related hazards requires understanding fluvial transport of material liberated in earthquake-triggered landslides. The location of landslides relative to river channels is expected to play an important role in postearthquake sediment dynamics. In this study, we assess the position of landslides triggered by the Mw 7.9 Wenchuan earthquake, aiming to understand the relationship between landslides and the fluvial network of the steep Longmen Shan mountain range. Combining a landslide inventory map and geomorphic analysis, we quantify landslide-channel connectivity in terms of the number of landslides, landslide area, and landslide volume estimated from scaling relationships. We observe a strong spatial variability in landslide-channel connectivity, with volumetric connectivity (ξ) ranging from ~20% to ~90% for different catchments. This variability is linked to topographic effects that set local channel densities, seismic effects (including seismogenic faulting) that regulate landslide size, and substrate effects that may influence both channelization and landslide size. Altogether, we estimate that the volume of landslides connected to channels comprises 43 + 9/-7% of the total coseismic landslide volume. Following the Wenchuan earthquake, fine-grained (90% of the total landslide volume) may be more significantly affected by landslide locations.

  8. The music of earthquakes and Earthquake Quartet #1 (United States)

    Michael, Andrew J.


    Earthquake Quartet #1, my composition for voice, trombone, cello, and seismograms, is the intersection of listening to earthquakes as a seismologist and performing music as a trombonist. Along the way, I realized there is a close relationship between what I do as a scientist and what I do as a musician. A musician controls the source of the sound and the path it travels through their instrument in order to make sound waves that we hear as music. An earthquake is the source of waves that travel along a path through the earth until reaching us as shaking. It is almost as if the earth is a musician and people, including seismologists, are metaphorically listening and trying to understand what the music means.

  9. Using earthquake intensities to forecast earthquake occurrence times

    Directory of Open Access Journals (Sweden)

    J. R. Holliday


    Full Text Available It is well known that earthquakes do not occur randomly in space and time. Foreshocks, aftershocks, precursory activation, and quiescence are just some of the patterns recognized by seismologists. Using the Pattern Informatics technique along with relative intensity analysis, we create a scoring method based on time dependent relative operating characteristic diagrams and show that the occurrences of large earthquakes in California correlate with time intervals where fluctuations in small earthquakes are suppressed relative to the long term average. We estimate a probability of less than 1% that this coincidence is due to random clustering. Furthermore, we show that the methods used to obtain these results may be applicable to other parts of the world.


    Takahashi, Masanori; Takayama, Jun-Ichi; Nakayama, Shoichiro

    Noto Peninsula earthquake occurred in Ishikawa Pref., in March, 2007, and the Noto Yuryo, and many arterial roads were damaged. This led to the conosiderable confusion of the road traffic in Noto Peninsula area and gave the influence on all kinds of social/economic activities. Therefore, an method of providing the traffic information for drivers is important in the case of disasters such as earthquakes. We carried out a questionnaire survey for local inhabitants and investigated the road use situation at the time of the Noto Peninsula earthquake and the information acquisition situation about it. We also analyzed whether or not the method of providing the traffic information was appropriate. In addition, we examined the best traffic information in the case of earthquakes.

  11. Earthquake forecast via neutrino tomography

    Institute of Scientific and Technical Information of China (English)

    WANG Bin; CHEN Ya-Zheng; LI Xue-Qian


    We discuss the possibility of forecasting earthquakes by means of (anti)neutrino tomography. An- tineutrinos emitted from reactors are used as a probe. As the antineutrinos traverse through a region prone to earthquakes, observable variations in the matter effect on the antineutrino oscillation would provide a tomog- raphy of the vicinity of the region. In this preliminary work, we adopt a simplified model for the geometrical profile and matter density in a fault zone. We calculate the survival probability of electron antineutrinos for cases without and with an anomalous accumulation of electrons which can be considered as a clear signal of the coming earthquake, at the geological region with a fault zone, and find that the variation may reach as much as 3% for ν emitted from a reactor. The case for a ν beam from a neutrino factory is also investigated, and it is noted that, because of the typically high energy associated with such neutrinos, the oscillation length is too large and the resultant variation is not practically observable. Our conclusion is that with the present reactor facilities and detection techniques, it is still a difficult task to make an earthquake forecast using such a scheme, though it seems to be possible from a theoretical point of view while ignoring some uncertainties. However, with the development of the geology, especially the knowledge about the fault zone, and with the improvement of the detection techniques, etc., there is hope that a medium-term earthquake forecast would be feasible.

  12. Triggering of Aftershocks of the Japan 2011 Earthquake by Earth Tides

    CERN Document Server

    Datta, Arjun


    The aftershock sequence of the devastating Japan earthquake of March 2011 is analyzed for the presence of periodicities at the Earth tide periods. We use spectral analysis as well as a time-domain method KORRECT developed earlier to detect presence of diurnal and semi-diurnal periodicities in the sequence of aftershocks (M \\geq 4). This suggests that large aftershocks in the fault zone of the Japan 2011 earthquake were strongly influenced by Earth tides.

  13. Retrospection on the Conclusions of Earthquake Tendency Forecast before the Wenchuan Ms8.0 Earthquake

    Institute of Scientific and Technical Information of China (English)

    Liu Jie; Guo Tieshuan; Yang Liming; Su Youjin; Li Gang


    The reason for the failure to forecast the Wenchuan Ms8.0 earthquake is under study, based on the systematically collection of the seismicity anomalies and their analysis results from annual earthquake tendency forecasts between the 2001 Western Kuulun Mountains Pass Ms8.1 earthquake and the 2008 Wenchuan Ms8.0 earthquake. The results show that the earthquake tendency estimation of Chinese Mainland is for strong earthquakes to occur in the active stage, and that there is still potential for the occurrence of a Ms8.0 large earthquake in Chinese Mainland after the 2001 Western Kunlun Mountains Pass earthquake. However the phenomena that many large earthquakes occurred around Chinese Mainland, and the 6-year long quietude of Ms7.0 earthquake and an obvious quietude of Ms5.0 and Ms6.0 earthquakes during 2002 ~2007 led to the distinctly lower forecast estimation of earthquake tendency in Chinese Mainland after 2006. The middle part in the north-south seismic belt has been designated a seismic risk area of strong earthquake in recent years, but, the estimation of the risk degree in Southwestern China is insufficient after the Ning'er Ms6.4 earthquake in Yunnan in 2007. There are no records of earthquakes with Ms≥7.0 in the Longmenshan fault, which is one of reasons that this fault was not considered a seismic risk area of strong earthquakes in recent years.

  14. Earthquakes in Central California, 1980-1984 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — There have been many earthquake occurrences in central California. This set of slides shows earthquake damage from the following events: Livermore, 1980, Coalinga,...

  15. Extreme value distribution of earthquake magnitude (United States)

    Zi, Jun Gan; Tung, C. C.


    Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent.

  16. The October 12, 1992, Dahshur, Egypt, Earthquake (United States)

    Thenhaus, P.C.; Celebi, M.; Sharp, R.V.


    Cairo and northeastern Egypt experienced a rare, damaging earthquake on October 12, 1992. The earthquake, which measured 5.9 on the Richter magnitude scale, was centered near the village of Dahshur, about 18 km south of Cairo. The computed hypocentral depth of the earthquake, about 25 km, is consistent with the fact that fault rupture associated with the earthquake did not reach the surface. 

  17. Nonstationary ETAS models for nonstandard earthquakes


    Kumazawa, Takao; Ogata, Yosihiko


    The conditional intensity function of a point process is a useful tool for generating probability forecasts of earthquakes. The epidemic-type aftershock sequence (ETAS) model is defined by a conditional intensity function, and the corresponding point process is equivalent to a branching process, assuming that an earthquake generates a cluster of offspring earthquakes (triggered earthquakes or so-called aftershocks). Further, the size of the first-generation cluster depends on the magnitude of...


    Directory of Open Access Journals (Sweden)

    Mustafa ULAS


    Full Text Available lot of people have died because of earthquakes every year. Therefore It is crucial to predict the time of the earthquakes reasonable time before it had happed. This paper presents recent information published in the literature about precursors of earthquakes. The relationships between earthquakes and ionosphere are targeted to guide new researches in order to study further to find novel prediction methods.

  19. Historical earthquake investigations in Greece

    Directory of Open Access Journals (Sweden)

    K. Makropoulos


    Full Text Available The active tectonics of the area of Greece and its seismic activity have always been present in the country?s history. Many researchers, tempted to work on Greek historical earthquakes, have realized that this is a task not easily fulfilled. The existing catalogues of strong historical earthquakes are useful tools to perform general SHA studies. However, a variety of supporting datasets, non-uniformly distributed in space and time, need to be further investigated. In the present paper, a review of historical earthquake studies in Greece is attempted. The seismic history of the country is divided into four main periods. In each one of them, characteristic examples, studies and approaches are presented.

  20. Fault geometry and earthquake mechanics

    Directory of Open Access Journals (Sweden)

    D. J. Andrews


    Full Text Available Earthquake mechanics may be determined by the geometry of a fault system. Slip on a fractal branching fault surface can explain: 1 regeneration of stress irregularities in an earthquake; 2 the concentration of stress drop in an earthquake into asperities; 3 starting and stopping of earthquake slip at fault junctions, and 4 self-similar scaling of earthquakes. Slip at fault junctions provides a natural realization of barrier and asperity models without appealing to variations of fault strength. Fault systems are observed to have a branching fractal structure, and slip may occur at many fault junctions in an earthquake. Consider the mechanics of slip at one fault junction. In order to avoid a stress singularity of order 1/r, an intersection of faults must be a triple junction and the Burgers vectors on the three fault segments at the junction must sum to zero. In other words, to lowest order the deformation consists of rigid block displacement, which ensures that the local stress due to the dislocations is zero. The elastic dislocation solution, however, ignores the fact that the configuration of the blocks changes at the scale of the displacement. A volume change occurs at the junction; either a void opens or intense local deformation is required to avoid material overlap. The volume change is proportional to the product of the slip increment and the total slip since the formation of the junction. Energy absorbed at the junction, equal to confining pressure times the volume change, is not large enongh to prevent slip at a new junction. The ratio of energy absorbed at a new junction to elastic energy released in an earthquake is no larger than P/µ where P is confining pressure and µ is the shear modulus. At a depth of 10 km this dimensionless ratio has th value P/µ= 0.01. As slip accumulates at a fault junction in a number of earthquakes, the fault segments are displaced such that they no longer meet at a single point. For this reason the

  1. EARTHQUAKES - VOLCANOES (Causes - Forecast - Counteraction) (United States)

    Tsiapas, Elias


    Earthquakes and volcanoes are caused by: 1)Various liquid elements (e.g. H20, H2S, S02) which emerge from the pyrosphere and are trapped in the space between the solid crust and the pyrosphere (Moho discontinuity). 2)Protrusions of the solid crust at the Moho discontinuity (mountain range roots, sinking of the lithosphere's plates). 3)The differential movement of crust and pyrosphere. The crust misses one full rotation for approximately every 100 pyrosphere rotations, mostly because of the lunar pull. The above mentioned elements can be found in small quantities all over the Moho discontinuity, and they are constantly causing minor earthquakes and small volcanic eruptions. When large quantities of these elements (H20, H2S, SO2, etc) concentrate, they are carried away by the pyrosphere, moving from west to east under the crust. When this movement takes place under flat surfaces of the solid crust, it does not cause earthquakes. But when these elements come along a protrusion (a mountain root) they concentrate on its western side, displacing the pyrosphere until they fill the space created. Due to the differential movement of pyrosphere and solid crust, a vacuum is created on the eastern side of these protrusions and when the aforementioned liquids overfill this space, they explode, escaping to the east. At the point of their escape, these liquids are vaporized and compressed, their flow accelerates, their temperature rises due to fluid friction and they are ionized. On the Earth's surface, a powerful rumbling sound and electrical discharges in the atmosphere, caused by the movement of the gasses, are noticeable. When these elements escape, the space on the west side of the protrusion is violently taken up by the pyrosphere, which collides with the protrusion, causing a major earthquake, attenuation of the protrusions, cracks on the solid crust and damages to structures on the Earth's surface. It is easy to foresee when an earthquake will occur and how big it is

  2. 13 CFR 120.174 - Earthquake hazards. (United States)


    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Earthquake hazards. 120.174... Applying to All Business Loans Requirements Imposed Under Other Laws and Orders § 120.174 Earthquake..., the construction must conform with the “National Earthquake Hazards Reduction Program...

  3. Earthquake Education in Prime Time (United States)

    de Groot, R.; Abbott, P.; Benthien, M.


    Since 2001, the Southern California Earthquake Center (SCEC) has collaborated on several video production projects that feature important topics related to earthquake science, engineering, and preparedness. These projects have also fostered many fruitful and sustained partnerships with a variety of organizations that have a stake in hazard education and preparedness. The Seismic Sleuths educational video first appeared in the spring season 2001 on Discovery Channel's Assignment Discovery. Seismic Sleuths is based on a highly successful curriculum package developed jointly by the American Geophysical Union and The Department of Homeland Security Federal Emergency Management Agency. The California Earthquake Authority (CEA) and the Institute for Business and Home Safety supported the video project. Summer Productions, a company with a reputation for quality science programming, produced the Seismic Sleuths program in close partnership with scientists, engineers, and preparedness experts. The program has aired on the National Geographic Channel as recently as Fall 2004. Currently, SCEC is collaborating with Pat Abbott, a geology professor at San Diego State University (SDSU) on the video project Written In Stone: Earthquake Country - Los Angeles. Partners on this project include the California Seismic Safety Commission, SDSU, SCEC, CEA, and the Insurance Information Network of California. This video incorporates live-action demonstrations, vivid animations, and a compelling host (Abbott) to tell the story about earthquakes in the Los Angeles region. The Written in Stone team has also developed a comprehensive educator package that includes the video, maps, lesson plans, and other supporting materials. We will present the process that facilitates the creation of visually effective, factually accurate, and entertaining video programs. We acknowledge the need to have a broad understanding of the literature related to communication, media studies, science education, and

  4. Computational methods in earthquake engineering

    CERN Document Server

    Plevris, Vagelis; Lagaros, Nikos


    This is the third book in a series on Computational Methods in Earthquake Engineering. The purpose of this volume is to bring together the scientific communities of Computational Mechanics and Structural Dynamics, offering a wide coverage of timely issues on contemporary Earthquake Engineering. This volume will facilitate the exchange of ideas in topics of mutual interest and can serve as a platform for establishing links between research groups with complementary activities. The computational aspects are emphasized in order to address difficult engineering problems of great social and economic importance. .

  5. Dancing Earthquake Science Assists Recovery from the Christchurch Earthquakes (United States)

    Egan, Candice J.; Quigley, Mark C.


    The 2010-2012 Christchurch (Canterbury) earthquakes in New Zealand caused loss of life and psychological distress in residents throughout the region. In 2011, student dancers of the Hagley Dance Company and dance professionals choreographed the performance "Move: A Seismic Journey" for the Christchurch Body Festival that explored…

  6. Diurnal changes of earthquake activity and geomagnetic Sq-variations

    Directory of Open Access Journals (Sweden)

    G. Duma


    Full Text Available Statistic analyses demonstrate that the probability of earthquake occurrence in many earthquake regions strongly depends on the time of day, that is on Local Time (e.g. Conrad, 1909, 1932; Shimshoni, 1971; Duma, 1997; Duma and Vilardo, 1998. This also applies to strong earthquake activity. Moreover, recent observations reveal an involvement of the regular diurnal variations of the Earth’s magnetic field, commonly known as Sq-variations, in this geodynamic process of changing earthquake activity with the time of day (Duma, 1996, 1999. In the article it is attempted to quantify the forces which result from the interaction between the induced Sq-variation currents in the Earth’s lithosphere and the regional Earth’s magnetic field, in order to assess the influence on the tectonic stress field and on seismic activity. A reliable model is obtained, which indicates a high energy involved in this process. The effect of Sq-induction is compared with the results of the large scale electromagnetic experiment "Khibiny" (Velikhov, 1989, where a giant artificial current loop was activated in the Barents Sea.

  7. Anomalous frequency characteristics of groundwater levels before major earthquakes in Taiwan

    Directory of Open Access Journals (Sweden)

    C.-H. Chen


    Full Text Available Unusual decreases in water levels were consistently observed in 78% (=42/54 of the wells in the Choshuichi Alluvial Fan of central Taiwan roughly 150 days before the Chi-Chi earthquake (M = 7.6 on 20 September 1999 when the influences of barometric pressure, earth tides, precipitation and artificial pumping were removed. Variations in groundwater levels measured in the anomalous wells between 1 August 1997 and 19 September 1999, the time period covering the unusual decreases, were transferred into the frequency domain to examine anomalous frequency bands associated with the Chi-Chi earthquake. Analytical results show that amplitudes at the frequency band between 0.02 day−1 and 0.04 day−1 were generally maintained at the low stage and were enhanced in the few weeks before the Chi-Chi earthquake. Variations in amplitude within this particular frequency band were further examined in association with earthquakes (M > 6 between 1 August 1997 and 31 December 2009. Enhanced amplitude phenomena are consistently observed prior to the other two earthquakes (the Rei-Li and Ming-Jian earthquakes during the 12.5 yr, which sheds a promising light on research into precursors of strong earthquakes when combined with other geophysical observations such as geomagnetic anomalies and crustal displacements.

  8. Scenario-based earthquake hazard and risk assessment for Baku (Azerbaijan

    Directory of Open Access Journals (Sweden)

    G. Babayev


    Full Text Available A rapid growth of population, intensive civil and industrial building, land and water instabilities (e.g. landslides, significant underground water level fluctuations, and the lack of public awareness regarding seismic hazard contribute to the increase of vulnerability of Baku (the capital city of the Republic of Azerbaijan to earthquakes. In this study, we assess an earthquake risk in the city determined as a convolution of seismic hazard (in terms of the surface peak ground acceleration, PGA, vulnerability (due to building construction fragility, population features, the gross domestic product per capita, and landslide's occurrence, and exposure of infrastructure and critical facilities. The earthquake risk assessment provides useful information to identify the factors influencing the risk. A deterministic seismic hazard for Baku is analysed for four earthquake scenarios: near, far, local, and extreme events. The seismic hazard models demonstrate the level of ground shaking in the city: PGA high values are predicted in the southern coastal and north-eastern parts of the city and in some parts of the downtown. The PGA attains its maximal values for the local and extreme earthquake scenarios. We show that the quality of buildings and the probability of their damage, the distribution of urban population, exposure, and the pattern of peak ground acceleration contribute to the seismic risk, meanwhile the vulnerability factors play a more prominent role for all earthquake scenarios. Our results can allow elaborating strategic countermeasure plans for the earthquake risk mitigation in the Baku city.

  9. Seismicity dynamics and earthquake predictability

    Directory of Open Access Journals (Sweden)

    G. A. Sobolev


    Full Text Available Many factors complicate earthquake sequences, including the heterogeneity and self-similarity of the geological medium, the hierarchical structure of faults and stresses, and small-scale variations in the stresses from different sources. A seismic process is a type of nonlinear dissipative system demonstrating opposing trends towards order and chaos. Transitions from equilibrium to unstable equilibrium and local dynamic instability appear when there is an inflow of energy; reverse transitions appear when energy is dissipating. Several metastable areas of a different scale exist in the seismically active region before an earthquake. Some earthquakes are preceded by precursory phenomena of a different scale in space and time. These include long-term activation, seismic quiescence, foreshocks in the broad and narrow sense, hidden periodical vibrations, effects of the synchronization of seismic activity, and others. Such phenomena indicate that the dynamic system of lithosphere is moving to a new state – catastrophe. A number of examples of medium-term and short-term precursors is shown in this paper. However, no precursors identified to date are clear and unambiguous: the percentage of missed targets and false alarms is high. The weak fluctuations from outer and internal sources play a great role on the eve of an earthquake and the occurrence time of the future event depends on the collective behavior of triggers. The main task is to improve the methods of metastable zone detection and probabilistic forecasting.

  10. Earthquake design for controlled structures

    Directory of Open Access Journals (Sweden)

    Nikos G. Pnevmatikos


    Full Text Available An alternative design philosophy, for structures equipped with control devices, capable to resist an expected earthquake while remaining in the elastic range, is described. The idea is that a portion of the earthquake loading is under¬taken by the control system and the remaining by the structure which is designed to resist elastically. The earthquake forces assuming elastic behavior (elastic forces and elastoplastic behavior (design forces are first calculated ac¬cording to the codes. The required control forces are calculated as the difference from elastic to design forces. The maximum value of capacity of control devices is then compared to the required control force. If the capacity of the control devices is larger than the required control force then the control devices are accepted and installed in the structure and the structure is designed according to the design forces. If the capacity is smaller than the required control force then a scale factor, α, reducing the elastic forces to new design forces is calculated. The structure is redesigned and devices are installed. The proposed procedure ensures that the structure behaves elastically (without damage for the expected earthquake at no additional cost, excluding that of buying and installing the control devices.

  11. Automatic earthquake confirmation for early warning system (United States)

    Kuyuk, H. S.; Colombelli, S.; Zollo, A.; Allen, R. M.; Erdik, M. O.


    Earthquake early warning studies are shifting real-time seismology in earthquake science. They provide methods to rapidly assess earthquakes to predict damaging ground shaking. Preventing false alarms from these systems is key. Here we developed a simple, robust algorithm, Authorizing GRound shaking for Earthquake Early warning Systems (AGREEs), to reduce falsely issued alarms. This is a network threshold-based algorithm, which differs from existing approaches based on apparent velocity of P and S waves. AGREEs is designed to function as an external module to support existing earthquake early warning systems (EEWSs) and filters out the false events, by evaluating actual shaking near the epicenter. Our retrospective analyses of the 2009 L'Aquila and 2012 Emilia earthquakes show that AGREEs could help an EEWS by confirming the epicentral intensity. Furthermore, AGREEs is able to effectively identify three false events due to a storm, a teleseismic earthquake, and broken sensors in Irpinia Seismic Network, Italy.

  12. On the agreement between small-world-like OFC model and real earthquakes

    CERN Document Server

    Ferreira, Douglas S R; Menezes, Ronaldo


    In this article we implemented simulations of the OFC model for earthquakes for two different topologies: regular and small-world, where in the latter the links are randomly rewired with probability $p$ . In both topologies, we have studied the distribution of time intervals between consecutive earthquakes and the border effects present in each one. In addition, we also have characterized the influence that the probability $p$ produces in certain characteristics of the lattice and in the intensity of border effects. From the two topologies, networks of consecutive epicenters were constructed, that allowed us to analyze the distribution of connectivities of each one. In our results distributions arise belonging to a family of non-traditional distributions functions, which agrees with previous studies using data from actual earthquakes. Our results reinforce the idea that the Earth is in a critical self-organized state and furthermore point towards temporal and spatial correlations between earthquakes in differ...

  13. The "SABEIS" Project: Warning systems based on earthquake and tsunamis-induced ionospheric effects. (United States)

    Rodriguez-Bouza, Marta; Sánchez-Dulcet, Francisco; Herraiz, Miguel; Rodríguez-Caderot, Gracia; Altadill, David; Blanch, Estefania; Santoyo, Miguel Angel


    The study of a possible lithosphere-atmosphere-ionosphere coupling (LAI) is mainly focused on the analysis and comprehension of atmospheric and ionospheric anomalies caused by extreme lithospheric events. In this context, earthquakes are considered as possible sources of atmosphere-ionosphere anomalies. The goal of the two-year long project SABEIS (Sistemas de Alerta Basados en Efectos de terremotos y tsunamis en la IonoSfera) granted by the Spanish Ministry of Economy and Competitiveness, is to analyze the disturbances caused by earthquakes and tsunamis and their possible contribution to warning systems. These topics are receiving increased attention in the scientific community and their correct understanding can meaningfully contribute to the protection of people and economic assets in areas subject to seismic threat. The project is based on the analysis of Total Electron Content (TEC) obtained from signals of Global Navigation Satellite Systems (GNSS) and anomalies of the ionospheric F2 layer observed in ionograms. This methodology was partially applied in a previous study of the Mw6.1 earthquake in Greece occurred on January 26, 2014. In that case two TEC disturbances were detected the days prior the earthquake. The first one, four days before, was registered by the majority of the stations analyzed over Europe and after studying its temporal variation, was considered unrelated to the earthquake. The second one occurred the day before the earthquake. This anomaly appeared only at stations close to the epicenter and their temporal proximity to the earthquake point to a possible connection with the earthquake preparation process. In the SABEIS project possible anomalies caused by earthquakes in Mexico and Peru with magnitude ranging from 5.5 to 8.2, will be studied. If the results confirm the influence of seismic events on the ionosphere, the possibility of incorporating this type of analysis in a seismic alert network for the Gulf of Cadiz (southern Iberian

  14. Tectonic controls on earthquake size distribution and seismicity rate: slab buoyancy and slab bending (United States)

    Nishikawa, T.; Ide, S.


    There are clear variations in maximum earthquake magnitude among Earth's subduction zones. These variations have been studied extensively and attributed to differences in tectonic properties in subduction zones, such as relative plate velocity and subducting plate age [Ruff and Kanamori, 1980]. In addition to maximum earthquake magnitude, the seismicity of medium to large earthquakes also differs among subduction zones, such as the b-value (i.e., the slope of the earthquake size distribution) and the frequency of seismic events. However, the casual relationship between the seismicity of medium to large earthquakes and subduction zone tectonics has been unclear. Here we divide Earth's subduction zones into over 100 study regions following Ide [2013] and estimate b-values and the background seismicity rate—the frequency of seismic events excluding aftershocks—for subduction zones worldwide using the maximum likelihood method [Utsu, 1965; Aki, 1965] and the epidemic type aftershock sequence (ETAS) model [Ogata, 1988]. We demonstrate that the b-value varies as a function of subducting plate age and trench depth, and that the background seismicity rate is related to the degree of slab bending at the trench. Large earthquakes tend to occur relatively frequently (lower b-values) in shallower subduction zones with younger slabs, and more earthquakes occur in subduction zones with deeper trench and steeper dip angle. These results suggest that slab buoyancy, which depends on subducting plate age, controls the earthquake size distribution, and that intra-slab faults due to slab bending, which increase with the steepness of the slab dip angle, have influence on the frequency of seismic events, because they produce heterogeneity in plate coupling and efficiently inject fluid to elevate pore fluid pressure on the plate interface. This study reveals tectonic factors that control earthquake size distribution and seismicity rate, and these relationships between seismicity and

  15. Comparison of earthquake source parameters and interseismic plate coupling variations in global subduction zones (Invited) (United States)

    Bilek, S. L.; Moyer, P. A.; Stankova-Pursley, J.


    Geodetically determined interseismic coupling variations have been found in subduction zones worldwide. These coupling variations have been linked to heterogeneities in interplate fault frictional conditions. These connections to fault friction imply that observed coupling variations are also important in influencing details in earthquake rupture behavior. Because of the wealth of newly available geodetic models along many subduction zones, it is now possible to examine detailed variations in coupling and compare to seismicity characteristics. Here we use a large catalog of earthquake source time functions and slip models for moderate to large magnitude earthquakes to explore these connections, comparing earthquake source parameters with available models of geodetic coupling along segments of the Japan, Kurile, Kamchatka, Peru, Chile, and Alaska subduction zones. In addition, we use published geodetic results along the Costa Rica margin to compare with source parameters of small magnitude earthquakes recorded with an onshore-offshore network of seismometers. For the moderate to large magnitude earthquakes, preliminary results suggest a complex relationship between earthquake parameters and estimates of strongly and weakly coupled segments of the plate interface. For example, along the Kamchatka subduction zone, these earthquakes occur primarily along the transition between strong and weak coupling, with significant heterogeneity in the pattern of moment scaled duration with respect to the coupling estimates. The longest scaled duration event in this catalog occurred in a region of strong coupling. Earthquakes along the transition between strong and weakly coupled exhibited the most complexity in the source time functions. Use of small magnitude (0.5 Osa Peninsula relative to the Nicoya Peninsula, mimicking the along-strike variations in calculated interplate coupling.

  16. Earthquake safety assessment of concrete arch and gravity dams

    Institute of Scientific and Technical Information of China (English)

    Lin Gao; Hu Zhiqiang


    Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

  17. Strong motions and engineering structure performances in recent major earthquakes

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Li


    @@ In recent years, a series of major earthquakes occurred, which resulted in considerable engineering damage and collapse, triggered heavy geological hazards, and caused extremely high casualties and huge property and economic loss. The earthquakes include the 1994 Northridge earthquake (M6.8), the 1995 Kobe earthquake (M6.8), the 1999 Izmit earthquake (M7.6), the 1999 Jiji (Chi-Chi) earthquake (M7.6), the 2005 northern Pakistan earthquake (M7.6), the 2008 Wenchuan earthquake (M8.0) and the 2010 Haiti earthquake (M7.0). Some villages, towns and even cities were devastated in the earthquakes, especially in the 2005 northern Pakistan earthquake, the 2008 Wenchuan earthquake and the 2010 Haiti earthquake.

  18. Estimation of Future Earthquake Losses in California (United States)

    Rowshandel, B.; Wills, C. J.; Cao, T.; Reichle, M.; Branum, D.


    Recent developments in earthquake hazards and damage modeling, computing, and data management and processing, have made it possible to develop estimates of the levels of damage from earthquakes that may be expected in the future in California. These developments have been mostly published in the open literature, and provide an opportunity to estimate the levels of earthquake damage Californians can expect to suffer during the next several decades. Within the past 30 years, earthquake losses have increased dramatically, mostly because our exposure to earthquake hazards has increased. All but four of the recent damaging earthquakes have occurred distant from California's major population centers. Two, the Loma Prieta earthquake and the San Fernando earthquake, occurred on the edges of major populated areas. Loma Prieta caused significant damage in the nearby Santa Cruz and in the more distant, heavily populated, San Francisco Bay area. The 1971 San Fernando earthquake had an epicenter in the lightly populated San Gabriel Mountains, but caused slightly over 2 billion dollars in damage in the Los Angeles area. As urban areas continue to expand, the population and infrastructure at risk increases. When earthquakes occur closer to populated areas, damage is more significant. The relatively minor Whittier Narrows earthquake of 1987 caused over 500 million dollars in damage because it occurred in the Los Angeles metropolitan area, not at its fringes. The Northridge earthquake had fault rupture directly beneath the San Fernando Valley, and caused about 46 billion dollars in damage. This vast increase in damage from the San Fernando earthquake reflected both the location of the earthquake directly beneath the populated area and the 23 years of continued development and resulting greater exposure to potential damage. We have calculated losses from potential future earthquake, both as scenarios of potential earthquakes and as annualized losses considering all the potential

  19. A Preliminary Study of the Types of Volcanic Earthquakes and Volcanic Activity at the Changbaishan Tianchi Volcano

    Institute of Scientific and Technical Information of China (English)

    Ming Yuehong; Su Wei; Fang Lihua


    Since 2002, a significant increase in seismicity, obvious ground deformation and geochemical anomalies have been observed in the Changbaishan Tianchi volcanic area. A series felt earthquakes occur near the caldera, causing great influence to society. In this paper, the types of volcanic earthquakes recorded by the temporal seismic network since 2002 have been classified by analyzing the spectrum, time-frequency characteristics and seismic waveforms at different stations. The risk of volcano eruptions was also estimated. Our results show that almost all earthquakes occurring in Tianchi volcano are volcanic-tectonic earthquakes. The low frequency seismic waveforms observed at a few stations may be caused by local mediums, and have no relation with long-period events. Although the level of seismicity increased obviously and earthquake swarms occurred more frequently than before, we considered that the magma activity is still in its early stage and the eruption risk of Changbaishan Tianchi volcano is still iow in the near future.

  20. Complexity of the Ibero-Magrhebian region: intermediate depth earthquakes (United States)

    Buforn, Elisa; Cesca, Simone; Del Fresno, Carmen; Udias, Agustin


    Complexity of the Ibero-Magrhebian region: intermediate depth earthquakes Buforn E. (1), Cesca S.(2), del Fresno C.(3), Udías, A. (1) (1) Dpt. Geofísica y Meteorología. Universidad Complutense, Madrid (Spain (2) Institute of Geophysics, University of Hamburg, Germany (3) Instituto Geográfico Nacional, Madrid (Spain) The Ibero-Magrhebian region is located at the plate boundary between Eurasia and Africa and it is a tectonically complex region. A sign of the complexity, is the occurrence of intermediate depth earthquakes (40earthquakes (h≈650) near Dúrcal (Granada). Intermediate depth shocks are mostly confined within a relatively narrow region (50 km width) located East of Gibraltar, extending NNE-SSW from the Malaga (Spain) area to a region offshore the Moroccan coast. The moderate magnitude of the intermediate depth events (less than 5.5), the heterogeneity of the crustal structure in the region, and the strong influence of microseismic noise on seismic data represent significant challenges for the inversion of focal mechanism based on waveform modelling. We have estimated the focal mechanisms of 9 intermediate depth earthquakes (Mw 3.3 to 4.5) occurred in the period 2002-2009 from moment tensor inversion of broad-band data at regional distances, using the recently developed Kiwi tools. Moment tensor inversion is carried out by fitting body waves amplitude spectra, solving for strike, dip, rake, scalar moment and improving the original hypocentral depth. For each earthquake, we carry out a set of inversions, comparing results using different station subsets, seismic phases and earth models. The new obtained results, together with other selected solutions estimated previously using different methods, show a change on the stress pattern: to the west of 4.5°W, focal mechanisms show vertical tension axis, while to the east

  1. Earthquake Forecasting as a System-Science Problem (United States)

    Jordan, T. H.


    renewal with the short-term clustering observed in aftershocks and extended seismic sequences. For this and other reasons, the stochastic ERFs are likely to be replaced, perhaps soon, by deterministic earthquake simulators that explicitly model rupture nucleation and stress evolution within fault systems. Several outstanding issues will be highlighted, such as the assimilation of historical seismicity data into simulator-based forecasting and the problem of forecasting rupture directivity, which can strongly influence ground motions.

  2. Hydrological anomalies connected to earthquakes in southern Apennines (Italy

    Directory of Open Access Journals (Sweden)

    E. Esposito


    Full Text Available The study of hydrological variations in the watersheds of seismic areas can be useful in order to acquire a new knowledge of the mechanisms by which earthquakes can produce hydrological anomalies. Italy has the availability of many long historical series both of hydrological parameters and of seismological data, and is an ideal laboratory to verify the validity of theoretical models proposed by various authors. In this work we analyse the hydrological anomalies associated with some of the big earthquakes that occurred in the last century in the southern Apennines: 1930, 1980 and 1984. For these earthquakes we analysed hydrometric and pluviometric data looking for significant anomalies in springs, water wells and mountain streams. The influence of rainfalls on the normal flows of rivers, springs and wells has been ascertained. Also, the earthquake of 1805, for which a lot of hydrological perturbations have been reported, is considered in order to point out effects imputable to this earthquake that can be similar to the effects of the other big earthquakes. The considered seismic events exhibit different modes of energy release, different focal mechanisms and different propagation of effects on the invested areas. Furthermore, even if their epicentres were not localised in contiguous seismogenetic areas, it seems that the hydrological effects imputable to them took place in the same areas. Such phenomena have been compared with macroseismic fields and transformed in parameters, in order to derive empirical relationships between the dimensions of the event and the characteristics of the hydrological variations. The results of this work point to a close dependence among hydrological anomalies, regional structures and fault mechanisms, and indicate that many clear anomalies have been forerunners of earthquakes. In 1993, the Naples Bureau of the Hydrographic National Service started the continuous monitoring of hydrologic parameters by a network of

  3. Earthquake Source Parameters Inferred from T-Wave Observations (United States)

    Perrot, J.; Dziak, R.; Lau, T. A.; Matsumoto, H.; Goslin, J.


    The seismicity of the North Atlantic Ocean has been recorded by two networks of autonomous hydrophones moored within the SOFAR channel on the flanks of the Mid-Atlantic Ridge (MAR). In February 1999, a consortium of U.S. investigators (NSF and NOAA) deployed a 6-element hydrophone array for long-term monitoring of MAR seismicity between 15o-35oN south of the Azores. In May 2002, an international collaboration of French, Portuguese, and U.S. researchers deployed a 6-element hydrophone array north of the Azores Plateau from 40o-50oN. The northern network (referred to as SIRENA) was recovered in September 2003. The low attenuation properties of the SOFAR channel for earthquake T-wave propagation results in a detection threshold reduction from a magnitude completeness level (Mc) of ˜ 4.7 for MAR events recorded by the land-based seismic networks to Mc=3.0 using hydrophone arrays. Detailed focal depth and mechanism information, however, remain elusive due to the complexities of seismo-acoustic propagation paths. Nonetheless, recent analyses (Dziak, 2001; Park and Odom, 2001) indicate fault parameter information is contained within the T-wave signal packet. We investigate this relationship further by comparing an earthquake's T-wave duration and acoustic energy to seismic magnitude (NEIC) and radiation pattern (for events M>5) from the Harvard moment-tensor catalog. First results show earthquake energy is well represented by the acoustic energy of the T-waves, however T-wave codas are significantly influenced by acoustic propagation effects and do not allow a direct determination of the seismic magnitude of the earthquakes. Second, there appears to be a correlation between T-wave acoustic energy, azimuth from earthquake source to the hydrophone, and the radiation pattern of the earthquake's SH waves. These preliminary results indicate there is a relationship between the T-wave observations and earthquake source parameters, allowing for additional insights into T

  4. 心理外环境对学生抗逆力的影响研究--以汶川特大地震为例%The Influence of Outside Pyschological Environment on Students’ Resilience Competence---A Case Study of Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)



    文章以汶川特大地震为例,从家庭心理环境的家庭教育方式、家庭信念、家庭人际关系;学校心理环境的教师的影响、朋辈的影响和社会心理环境的政府援助、社会各界援助、解放军援助和心理工作者的介入这些外部心理环境因素分析对学生抗逆力的不同影响,以期找到提高学生抗逆力的方法。%The case of Wenchuan Earthquake is taken to explore various influence of the outside psychological environment on students’ resilience competence.The outside psychologi-cal environment in this case includes the family psychological environment,such as educational approach,faith and family members’ relationship,school psychological environment,such as the influence from teachers and peers, social psychological environment, such as the help and aid from government,all sectors of society,soldiers and psychologists.

  5. The Characteristics of Earthquake Swarms in and around Jiangsu Province

    Institute of Scientific and Technical Information of China (English)

    Huang Yun; Tian Jianming; Miao Ali


    This paper systematically analyzed 36 earthquake swarms in and around Jiangsu Province, summarized their characteristics and discussed the relationship between earthquske swarms and subsequent strong earthquakes. It also analyzed the judgment criteria for precursory earthquake swarms. Earthquake swarms in Jiangsu Province are concentrated in several areas. Most of them were of magnitude ML2. 0 ~ 3. 9. For most earthquake swarms, the number of earthquakes was less than 30. Time duration for about 55% of earthquake swarms was less than 15 days. The biggest magnitude of one earthquake swarm was not proportional to the number of earthquakes and time duration. There are 78% of earthquake swarms corresponded to the forthcoming earthquakes of M 〉 4. 6 in which there're 57% occured in one year, This shows a medium- and short-term criterion. Distance between earthquake swarm and future earthquake was distributed dispersedly. There were no earthquakes occurring in the same location as earthquake swarms. There was no good correlation between the magnitude and the corresponding rate of future earthquakes and the intensity of earthquake swarms. There was also no good correlation between the number of earthquakes in an earthquake swarm and the corresponding rate. The study also shows that it's better to use U-p or whole-combination to determine the type of earthquake swarm.

  6. Relation between the characteristics of strong earthquake activities in Chinese mainland and the Wenchuan earthquake

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Zhang; Guohua Yang; Xian Lu; Mingxiao Li; Zhigao Yang


    This paper studies the relations between the great Wenchuan earthquake and the active-quiet periodic characteristics of strong earthquakes, the rhythmic feature of great earthquakes, and the grouped spatial distribution of MS8.0 earthquakes in Chinese mainland. We also studied the relation between the Wenchuan earthquake and the stepwise migration characteristics of MS≥7.0 earthquakes on the North-South seismic belt, the features of the energy releasing acceleration in the active crustal blocks related to the Wenchuan earthquake and the relation between the Wenchuan earthquake and the so called second-arc fault zone. The results can be summarized as follows: ① the occurrence of the Wenchuan earthquake was consistent with the active-quiet periodic characteristics of strong earthquakes; ② its occurrence is consistent with the features of grouped occurrence of MS8.0 earthquakes and follows the 25 years rhythm (each circulation experiences the same time) of great earthquakes; ③ the Wenchuan MS8.0 earthquake follows the well known stepwise migration feature of strong earthquakes on the North-South seismic belt; ④ the location where the Wenchuan MS8.0 earthquake took place has an obvious consistency with the temporal and spatial characteristic of grouped activity of MS≥7.0 strong earthquakes on the second-arc fault zone; ⑤ the second-arc fault zone is not only the lower boundary for earthquakes with more than 30 km focal depth, but also looks like a lower boundary for deep substance movement; and ⑥ there are obvious seismic accelerations nearby the Qaidam and Qiangtang active crustal blocks (the northern and southern neighbors of the Bayan Har active block, respectively), which agrees with the GPS observation data.

  7. Update earthquake risk assessment in Cairo, Egypt (United States)

    Badawy, Ahmed; Korrat, Ibrahim; El-Hadidy, Mahmoud; Gaber, Hanan


    The Cairo earthquake (12 October 1992; m b = 5.8) is still and after 25 years one of the most painful events and is dug into the Egyptians memory. This is not due to the strength of the earthquake but due to the accompanied losses and damages (561 dead; 10,000 injured and 3000 families lost their homes). Nowadays, the most frequent and important question that should rise is "what if this earthquake is repeated today." In this study, we simulate the same size earthquake (12 October 1992) ground motion shaking and the consequent social-economic impacts in terms of losses and damages. Seismic hazard, earthquake catalogs, soil types, demographics, and building inventories were integrated into HAZUS-MH to produce a sound earthquake risk assessment for Cairo including economic and social losses. Generally, the earthquake risk assessment clearly indicates that "the losses and damages may be increased twice or three times" in Cairo compared to the 1992 earthquake. The earthquake risk profile reveals that five districts (Al-Sahel, El Basateen, Dar El-Salam, Gharb, and Madinat Nasr sharq) lie in high seismic risks, and three districts (Manshiyat Naser, El-Waily, and Wassat (center)) are in low seismic risk level. Moreover, the building damage estimations reflect that Gharb is the highest vulnerable district. The analysis shows that the Cairo urban area faces high risk. Deteriorating buildings and infrastructure make the city particularly vulnerable to earthquake risks. For instance, more than 90 % of the estimated buildings damages are concentrated within the most densely populated (El Basateen, Dar El-Salam, Gharb, and Madinat Nasr Gharb) districts. Moreover, about 75 % of casualties are in the same districts. Actually, an earthquake risk assessment for Cairo represents a crucial application of the HAZUS earthquake loss estimation model for risk management. Finally, for mitigation, risk reduction, and to improve the seismic performance of structures and assure life safety

  8. A smartphone application for earthquakes that matter! (United States)

    Bossu, Rémy; Etivant, Caroline; Roussel, Fréderic; Mazet-Roux, Gilles; Steed, Robert


    Smartphone applications have swiftly become one of the most popular tools for rapid reception of earthquake information for the public, some of them having been downloaded more than 1 million times! The advantages are obvious: wherever someone's own location is, they can be automatically informed when an earthquake has struck. Just by setting a magnitude threshold and an area of interest, there is no longer the need to browse the internet as the information reaches you automatically and instantaneously! One question remains: are the provided earthquake notifications always relevant for the public? What are the earthquakes that really matters to laypeople? One clue may be derived from some newspaper reports that show that a while after damaging earthquakes many eyewitnesses scrap the application they installed just after the mainshock. Why? Because either the magnitude threshold is set too high and many felt earthquakes are missed, or it is set too low and the majority of the notifications are related to unfelt earthquakes thereby only increasing anxiety among the population at each new update. Felt and damaging earthquakes are the ones that matter the most for the public (and authorities). They are the ones of societal importance even when of small magnitude. A smartphone application developed by EMSC (Euro-Med Seismological Centre) with the financial support of the Fondation MAIF aims at providing suitable notifications for earthquakes by collating different information threads covering tsunamigenic, potentially damaging and felt earthquakes. Tsunamigenic earthquakes are considered here to be those ones that are the subject of alert or information messages from the PTWC (Pacific Tsunami Warning Centre). While potentially damaging earthquakes are identified through an automated system called EQIA (Earthquake Qualitative Impact Assessment) developed and operated at EMSC. This rapidly assesses earthquake impact by comparing the population exposed to each expected

  9. The 2010-2011 Canterbury Earthquake Sequence: Environmental effects, seismic triggering thresholds and geologic legacy (United States)

    Quigley, Mark C.; Hughes, Matthew W.; Bradley, Brendon A.; van Ballegooy, Sjoerd; Reid, Catherine; Morgenroth, Justin; Horton, Travis; Duffy, Brendan; Pettinga, Jarg R.


    Seismic shaking and tectonic deformation during strong earthquakes can trigger widespread environmental effects. The severity and extent of a given effect relates to the characteristics of the causative earthquake and the intrinsic properties of the affected media. Documentation of earthquake environmental effects in well-instrumented, historical earthquakes can enable seismologic triggering thresholds to be estimated across a spectrum of geologic, topographic and hydrologic site conditions, and implemented into seismic hazard assessments, geotechnical engineering designs, palaeoseismic interpretations, and forecasts of the impacts of future earthquakes. The 2010-2011 Canterbury Earthquake Sequence (CES), including the moment magnitude (Mw) 7.1 Darfield earthquake and Mw 6.2, 6.0, 5.9, and 5.8 aftershocks, occurred on a suite of previously unidentified, primarily blind, active faults in the eastern South Island of New Zealand. The CES is one of Earth's best recorded historical earthquake sequences. The location of the CES proximal to and beneath a major urban centre enabled rapid and detailed collection of vast amounts of field, geospatial, geotechnical, hydrologic, biologic, and seismologic data, and allowed incremental and cumulative environmental responses to seismic forcing to be documented throughout a protracted earthquake sequence. The CES caused multiple instances of tectonic surface deformation (≥ 3 events), surface manifestations of liquefaction (≥ 11 events), lateral spreading (≥ 6 events), rockfall (≥ 6 events), cliff collapse (≥ 3 events), subsidence (≥ 4 events), and hydrological (10s of events) and biological shifts (≥ 3 events). The terrestrial area affected by strong shaking (e.g. peak ground acceleration (PGA) ≥ 0.1-0.3 g), and the maximum distances between earthquake rupture and environmental response (Rrup), both generally increased with increased earthquake Mw, but were also influenced by earthquake location and source

  10. An Atlas of ShakeMaps and population exposure catalog for earthquake loss modeling (United States)

    Allen, T.I.; Wald, D.J.; Earle, P.S.; Marano, K.D.; Hotovec, A.J.; Lin, K.; Hearne, M.G.


    We present an Atlas of ShakeMaps and a catalog of human population exposures to moderate-to-strong ground shaking (EXPO-CAT) for recent historical earthquakes (1973-2007). The common purpose of the Atlas and exposure catalog is to calibrate earthquake loss models to be used in the US Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER). The full ShakeMap Atlas currently comprises over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these maps constrained-to varying degrees-by instrumental ground motions, macroseismic intensity data, community internet intensity observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies. Exposure to discrete levels of shaking intensity is obtained by correlating Atlas ShakeMaps with a global population database. Combining this population exposure dataset with historical earthquake loss data, such as PAGER-CAT, provides a useful resource for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. We illustrate two example uses for EXPO-CAT; (1) simple objective ranking of country vulnerability to earthquakes, and; (2) the influence of time-of-day on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices tend to cluster spatially in terms of relative vulnerability. We also find little quantitative evidence to suggest that time-of-day is a significant factor in earthquake mortality. Moreover, earthquake mortality appears to be more systematically linked to the population exposed to severe ground shaking (Modified Mercalli Intensity VIII+). Finally, equipped with the full Atlas of ShakeMaps, we merge each of these maps and find the maximum estimated peak ground acceleration at any grid point in the world for the past 35 years. We subsequently compare this "composite ShakeMap" with existing global

  11. The 2012 MW5.6 earthquake in the vicinity of the city of Sofia (United States)

    Simeonova, Stela; Solakov, Dimcho; Aleksandrova, Irena; Dimitrova, Liliya; Popova, Iliana; Raykova, Plamena


    The territory of Bulgaria represents a typical example of high seismic risk area in the eastern part of the Balkan Peninsula. The neotectonic movements on the Balkan Peninsula were controlled by extensional collapse of the Late Alpin orogen, and were influenced by extension behind the Aegean arc and by the complicated vertical and horizontal movements in the Pannonian region. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia seismic zone that is the most populated (more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. Seismicity in the zone is related mainly to the marginal neotectonic faults of Sofia graben. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=IX-X MSK64. The 1858 earthquake caused heavy destruction in the town of Sofia and the appearance of thermal springs in the western part of the town. After a quiescence of about 50 years a strong event with M=6.5 occurred in 1905 near the western marginal part of the Sofia zone. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK64). The earthquake caused a lot of damages in the town and changed the capacity of the thermal mineral springs in Sofia and the surrounding villages. The earthquake was felt in an area of 50000 km2 and followed by aftershocks, which lasted more than one year. Almost a century later (95 years) an earthquake of moment magnitude 5.6 hit Sofia seismic zone, on May 22nd, 2012, at 25 km south west of the city of Sofia. This shallow earthquake was largely felt in the region and up to Greece, FYROM, Serbia and Romania. No severe injuries have been reported so far, though

  12. Earthquake Risk, FEMA Earthquake Hazzard Risk Map, Published in 1994, Delaware Geological Survey. (United States)

    NSGIC GIS Inventory (aka Ramona) — This Earthquake Risk dataset, was produced all or in part from Published Reports/Deeds information as of 1994. It is described as 'FEMA Earthquake Hazzard Risk Map'....

  13. A resonance mechanism of earthquakes

    CERN Document Server

    Flambaum, V V


    It had been observed in [1] that there are periodic 4-6 hours pulses of ? 200 ?Hz seismogravita- tional oscillations ( SGO ) before 95 % of powerful earthquakes. We explain this by beating between an oscillation eigenmode of a whole tectonic plate and a local eigenmode of an active zone which tranfers the oscillation energy from the tectonic plate to the active zone causing the eathrquake. Oscillation frequencies of the plate and ones of the active zone are tuned to a resonance by an additional pressure applied to the active zone due to collision of neighboring plates or convection in the upper mantia (plume). Corresponding theory may be used for short-term prediction of the earthquakes and tsunami.

  14. Great East Japan Earthquake Tsunami (United States)

    Iijima, Y.; Minoura, K.; Hirano, S.; Yamada, T.


    The 11 March 2011, Mw 9.0 Great East Japan Earthquake, already among the most destructive earthquakes in modern history, emanated from a fault rupture that extended an estimated 500 km along the Pacific coast of Honshu. This earthquake is the fourth among five of the strongest temblors since AD 1900 and the largest in Japan since modern instrumental recordings began 130 years ago. The earthquake triggered a huge tsunami, which invaded the seaside areas of the Pacific coast of East Japan, causing devastating damages on the coast. Artificial structures were destroyed and planted forests were thoroughly eroded. Inrush of turbulent flows washed backshore areas and dunes. Coastal materials including beach sand were transported onto inland areas by going-up currents. Just after the occurrence of the tsunami, we started field investigation of measuring thickness and distribution of sediment layers by the tsunami and the inundation depth of water in Sendai plain. Ripple marks showing direction of sediment transport were the important object of observation. We used a soil auger for collecting sediments in the field, and sediment samples were submitted for analyzing grain size and interstitial water chemistry. Satellite images and aerial photographs are very useful for estimating the hydrogeological effects of tsunami inundation. We checked the correspondence of micro-topography, vegetation and sediment covering between before and after the tsunami. The most conspicuous phenomenon is the damage of pine forests planted in the purpose of preventing sand shifting. About ninety-five percent of vegetation coverage was lost during the period of rapid currents changed from first wave. The landward slopes of seawalls were mostly damaged and destroyed. Some aerial photographs leave detailed records of wave destruction just behind seawalls, which shows the occurrence of supercritical flows. The large-scale erosion of backshore behind seawalls is interpreted to have been caused by

  15. Pre-earthquake Magnetic Pulses

    CERN Document Server

    Scoville, John; Freund, Friedemann


    A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are observable because their extremely long wavelength allows them to pass through the Earth's crust. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stress is building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  16. A Method for Estimation of Death Tolls in Disastrous Earthquake (United States)

    Pai, C.; Tien, Y.; Teng, T.


    whether the districts are more urbanized or not. As the present researches are concerned, there were not a good and reliable relationship between the mortality and the characteristics of ground motions. We propose the concept of Equal Population Gaps to resolve the influence of mortality in a rural or urban district and decision of the weighting function to each district. The relationship between PGA Index and the mortality determined in this study can be expressed as:\\[M=28.9/[1+exp{(1.67-0.0029 \\times PGA)}] \\] Here M is mortality in %, and PGA is PGA Index in gals. The corresponding curve matches the data reasonably well, with R2=0.91. We process the estimation for districts in different scales to verify the feasibility of the method. The mortality-based on PGA Index is particularly useful in real-time application for death tolls prediction and assessment--a piece of information most critical for post earthquake emergency response operation.

  17. The Value, Protocols, and Scientific Ethics of Earthquake Forecasting (United States)

    Jordan, Thomas H.


    Earthquakes are different from other common natural hazards because precursory signals diagnostic of the magnitude, location, and time of impending seismic events have not yet been found. Consequently, the short-term, localized prediction of large earthquakes at high probabilities with low error rates (false alarms and failures-to-predict) is not yet feasible. An alternative is short-term probabilistic forecasting based on empirical statistical models of seismic clustering. During periods of high seismic activity, short-term earthquake forecasts can attain prospective probability gains up to 1000 relative to long-term forecasts. The value of such information is by no means clear, however, because even with hundredfold increases, the probabilities of large earthquakes typically remain small, rarely exceeding a few percent over forecasting intervals of days or weeks. Civil protection agencies have been understandably cautious in implementing operational forecasting protocols in this sort of "low-probability environment." This paper will explore the complex interrelations among the valuation of low-probability earthquake forecasting, which must account for social intangibles; the protocols of operational forecasting, which must factor in large uncertainties; and the ethics that guide scientists as participants in the forecasting process, who must honor scientific principles without doing harm. Earthquake forecasts possess no intrinsic societal value; rather, they acquire value through their ability to influence decisions made by users seeking to mitigate seismic risk and improve community resilience to earthquake disasters. According to the recommendations of the International Commission on Earthquake Forecasting (, operational forecasting systems should appropriately separate the hazard-estimation role of scientists from the decision-making role of civil protection authorities and individuals. They should

  18. Tangshan Women After the Earthquake

    Institute of Scientific and Technical Information of China (English)


    TWENTY years ago, Tangshan, a city in China’s Hebei Province, was struck by an earthquake which killed 240,000 people, injured 160,000, and destroyed 10,200 homes. In 7,200 families there were no survivors. After 20 years of rebuilding, a new Tangshan has risen from the debris. Tangshan women played a very important role in rebuilding their hometown.

  19. Understand mountain studies from earthquake

    Institute of Scientific and Technical Information of China (English)


    @@ The Sichuan earthquake on 12 May was the most devastating one to hit China over the past 60 years or so. As the affected were mostly mountainous areas, serious damages were caused by various secondary disasters ranging from mountain collapse to the formation of quake lakes. This leaves Prof. DENG Wei, director-general of the Institute of Mountain Hazards and Environment, CAS, much to think about, and he is calling for strengthening studies on mountain science.

  20. Dim prospects for earthquake prediction (United States)

    Geller, Robert J.

    I was misquoted by C. Lomnitz's [1998] Forum letter (Eos, August 4, 1998, p. 373), which said: [I wonder whether Sasha Gusev [1998] actually believes that branding earthquake prediction a ‘proven nonscience’ [Geller, 1997a] is a paradigm for others to copy.”Readers are invited to verify for themselves that neither “proven nonscience” norv any similar phrase was used by Geller [1997a].

  1. Earthquakes in Virginia and vicinity 1774 - 2004 (United States)

    Tarr, Arthur C.; Wheeler, Russell L.


    This map summarizes two and a third centuries of earthquake activity. The seismic history consists of letters, journals, diaries, and newspaper and scholarly articles that supplement seismograph recordings (seismograms) dating from the early twentieth century to the present. All of the pre-instrumental (historical) earthquakes were large enough to be felt by people or to cause shaking damage to buildings and their contents. Later, widespread use of seismographs meant that tremors too small or distant to be felt could be detected and accurately located. Earthquakes are a legitimate concern in Virginia and parts of adjacent States. Moderate earthquakes cause slight local damage somewhere in the map area about twice a decade on the average. Additionally, many buildings in the map area were constructed before earthquake protection was added to local building codes. The large map shows all historical and instrumentally located earthquakes from 1774 through 2004.

  2. The physics of rock failure and earthquakes

    CERN Document Server

    Ohnaka, Mitiyasu


    Despite significant advances in the understanding of earthquake generation processes and derivation of underlying physical laws, controversy remains regarding the constitutive law for earthquake ruptures and how it should be formulated. Laboratory experiments are necessary to obtain high-resolution measurements that allow the physical nature of shear rupture processes to be deduced, and to resolve the controversy. This important book provides a deeper understanding of earthquake processes from nucleation to their dynamic propagation. Its key focus is a deductive approach based on laboratory-derived physical laws and formulae, such as a unifying constitutive law, a constitutive scaling law, and a physical model of shear rupture nucleation. Topics covered include: the fundamentals of rock failure physics, earthquake generation processes, physical scale dependence, and large-earthquake generation cycles. Designed for researchers and professionals in earthquake seismology, rock failure physics, geology and earthq...

  3. Is There An Earthquake Migration Global Pattern? (United States)

    dos Santos, A. M.; Franca, G. S.; da Silveira, A. G.; Frigeri, G. V.; Marotta, G. S.


    Earthquake migration patterns before large earthquake were proposed by Mogi (1968) and existence of the correlation between earthquakes over distances that show probable global interdependence and this theme is certainly one of the most intriguing in field of seismology. In this job, we will present the phenomenology of earthquake migration global seismic pattern empirically, in order to ensure statistically the correlation of long range and lead to confrontation these seismic patterns. We used the international catalog available, such as, NEIC-USGS. We find that the pair of events that have a good correlation are confirmed statistically. As Shebalin (1996) has shown the earthquake chain, we show this first stage of the earthquake prediction correlation for large distances.

  4. Earthquake forewarning in the Cascadia region (United States)

    Gomberg, Joan S.; Atwater, Brian F.; Beeler, Nicholas M.; Bodin, Paul; Davis, Earl; Frankel, Arthur; Hayes, Gavin P.; McConnell, Laura; Melbourne, Tim; Oppenheimer, David H.; Parrish, John G.; Roeloffs, Evelyn A.; Rogers, Gary D.; Sherrod, Brian; Vidale, John; Walsh, Timothy J.; Weaver, Craig S.; Whitmore, Paul M.


    This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings of increased probabilities of a damaging earthquake. We begin by clarifying some terminology; a “prediction” refers to a deterministic statement that a particular future earthquake will or will not occur. In contrast to the 0- or 100-percent likelihood of a deterministic prediction, a “forecast” describes the probability of an earthquake occurring, which may range from >0 to 4 earthquakes on the plate interface north of the Mendocino region 

  5. Investigation and influencing factors of mental health for senior students in post-wenchuan-earthquake%汶川地震后高三学生心理健康状况调查及其影响因素

    Institute of Scientific and Technical Information of China (English)

    梁川; 王桢; 江新会; 时勘


    目的 探讨地震后高三学生的应对方式,社会支持、抑郁、应激水平和心理健康之间的关系.方法 采用整群随机抽样的方法从都江堰灾区临时安置点的6所中学抽取820个学生,通过卫生部心理问题调查问卷、贝克抑郁量表、社会支持问卷、简易应对方式问卷等工具进行测量,运用方差、相关、分层回归等方法分析变量间的关系.结果 卫生部心理问题调查问卷得分[(7.49±4.41)分],贝克抑郁量表得分[(14.66±9.12)分]偏高.心理问题与抑郁症状、应激水平正相关(r=0.69、0.15),与积极应对、社会支持负相关(r=-0.33、-0.30).积极应对和社会支持的交互作用显著(β=0.14,△R2=0.02),抑郁症状和应激水平的交互作用显著(β=0.07,△R2=0.01).结论 抑郁是积极应对和心理问题的中介变量;社会支持是积极应对和抑郁之间的显著调节变量,随着社会支持的升高,积极应对的保护作用增强;应激水平是抑郁和心理问题之间的调节变量.%Objective This article mainly discuss the relationship among coping style,social support,de-pression,stress level and mental health in senior students after the earthquake. Methods 820 sample students were selected randomly from 6 middle schools in temporary inhabitancy of Dujiangyan area. Mental investigational questionnaire of China Ministry of Health, Beck Depression Inventory 2nd edition ( BDI-2), social support ques-tionnaire,simple coping style questionnaire (SCSQ) and other methods were used, and variance, correlation, and hierarchical regression to analyze the relationship of the variable. Results The account for mental investigational questionnaire of China Ministry of Health was (7.49±4.41 ) ,the scoring of B DI (14.66±9.12) was on the high side. Mental problems was positively correlated with depression symptom and stress level (r=0.69,0.15 ), while it was negatively correlated with positive coping and social support (r=-0.33, -0

  6. 关东大地震对东京市财政的影响%The Influence of the Great Kanto Earthquake on Public Finance of the City of Tokyo

    Institute of Scientific and Technical Information of China (English)



    1923年发生的关东大地震给日本带来惨重损失。作为主要受灾地,东京市1⃝的经济遭到沉重打击,在财政方面体现得尤为明显。地震造成东京市社会财富严重受损,财政收入缩减。而灾后的应急救援和城市重建却需要依靠大量财政资金,财政支出增多。对此,东京市财政力所不逮,只能依靠政府债务完成东京城市复兴事业,但累积债务也成为此后阻碍东京市经济发展的关键因素。%The Great Kanto Earthquake in 1923 was a holocaust for Japan where economy of Tokyo especially the finance of Tokyo suffered a critical hit. The disaster hit numerous social resource and the revenue greatly reduced. The disaster relief and reconstruction relied much on the financial funds and the fiscal expenditure increased. The financial capacity of Tokyo was therefore limited. Taking debt to recover from the disaster was the only way to cope with the Capital Reconstruction Project, and debt was one of the factors to hinder the economic development of Tokyo for the future.

  7. Storm sudden commencements and earthquakes (United States)

    Lavrov, Ivan; Sobisevich, Aleksey; Guglielmi, Anatol


    We have investigated statistically the problem of possible impact of the geomagnetic storm sudden com-mencement (SSC) on the global seismic activity. SSC are used as reference points for comparative analysis of seismicity by the method of superposed epoch. We selected 405 earthquakes from 1973 to 2010 with M˜5 magnitudes from a representative part of USGS Catalog. The comparative analysis of seismicity was carried out at the intervals of ˜60 min relative to the reference point. With a high degree of reliability, it was found that before the reference point the number of earthquakes is noticeably greater than after it. In other words, the global seismicity is suppressed by SSC. We refer to some studies in which the chemical, thermal and force mechanisms of the electromagnetic field action on rocks are discussed. We emphasize the incompleteness of the study concerning the correlation between SSC and earthquakes because we still do not succeed in understanding and interpreting the relationship in terms of physics and mathematics. The study need to be continued to solve this problem of interest and importance.

  8. Pre-earthquake magnetic pulses

    Directory of Open Access Journals (Sweden)

    J. Scoville


    Full Text Available A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are generated deep in the Earth's crust, in and around the Hypocentral volume, days or even weeks before Earthquakes. They are observable at the surface because their extremely long wavelength allows them to pass through kilometers of rock. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stresses are building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  9. Global Significant Earthquake Database, 2150 BC to present (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Significant Earthquake Database is a global listing of over 5,700 earthquakes from 2150 BC to the present. A significant earthquake is classified as one that...

  10. Earthquake risk assessment for Istanbul metropolitan area

    Institute of Scientific and Technical Information of China (English)


    The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associated risk for rational formulation of contingency plans and mitigation strategies. In urban centers, the seismic risk is best quantified and portrayed through the preparation of "Earthquake Damage and Loss Scenarios." The components of such scenarios are the assessment of the hazard, inventories and the vulnerabilities of elements at risk. For the development of the earthquake risk scenario in Istanbul, two independent approaches, one based on intensities and the second on spectral displacements, are utilized. This paper will present the important features of a comprehensive study, highlight the methodology, discuss the results and provide insights to future developments.

  11. Statistical tests of simple earthquake cycle models (United States)

    DeVries, Phoebe M. R.; Evans, Eileen L.


    A central goal of observing and modeling the earthquake cycle is to forecast when a particular fault may generate an earthquake: a fault late in its earthquake cycle may be more likely to generate an earthquake than a fault early in its earthquake cycle. Models that can explain geodetic observations throughout the entire earthquake cycle may be required to gain a more complete understanding of relevant physics and phenomenology. Previous efforts to develop unified earthquake models for strike-slip faults have largely focused on explaining both preseismic and postseismic geodetic observations available across a few faults in California, Turkey, and Tibet. An alternative approach leverages the global distribution of geodetic and geologic slip rate estimates on strike-slip faults worldwide. Here we use the Kolmogorov-Smirnov test for similarity of distributions to infer, in a statistically rigorous manner, viscoelastic earthquake cycle models that are inconsistent with 15 sets of observations across major strike-slip faults. We reject a large subset of two-layer models incorporating Burgers rheologies at a significance level of α = 0.05 (those with long-term Maxwell viscosities ηM 4.6 × 1020 Pa s) but cannot reject models on the basis of transient Kelvin viscosity ηK. Finally, we examine the implications of these results for the predicted earthquake cycle timing of the 15 faults considered and compare these predictions to the geologic and historical record.

  12. Thermal infrared anomalies of several strong earthquakes. (United States)

    Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying


    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

  13. Evaluation and cataloging of Korean historical earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kew Hwa; Han, Young Woo; Lee, Jun Hui; Park, Ji Eok; Na, Kwang Wooing; Shin, Byung Ju [The Reaearch Institute of Basic Sciences, Seoul Nationl Univ., Seoul (Korea, Republic of)


    In order to systematically collect and analyze the historical earthquake data of the Korean peninsula which are very important in analyzing the seismicity and seismic risk of the peninsula by seismologist and historian, extensive governmental and private historical documents are investigated and relative reliabilities of these documents are examined. This research unearthed about 70 new earthquake records and revealed the change in the cultural, political and social effects of earthquakes with time in Korea. Also, the results of the vibration test of the Korean traditional wooden house are obtained in order to better estimate intensities of the historical earthquakes.

  14. Retrospective cohort analysis of chest injury characteristics and concurrent injuries in patients admitted to hospital in the Wenchuan and Lushan earthquakes in Sichuan, China.

    Directory of Open Access Journals (Sweden)

    Xi Zheng

    Full Text Available BACKGROUND: The aim of this study was to compare retrospectively the characteristics of chest injuries and frequencies of other, concurrent injuries in patients after earthquakes of different seismic intensity. METHODS: We compared the cause, type, and body location of chest injuries as well as the frequencies of other, concurrent injuries in patients admitted to our hospital after the Wenchuan and Lushan earthquakes in Sichuan, China. We explored possible relationships between seismic intensity and the causes and types of injuries, and we assessed the ability of the Injury Severity Score, New Injury Severity Score, and Chest Injury Index to predict respiratory failure in chest injury patients. RESULTS: The incidence of chest injuries was 9.9% in the stronger Wenchuan earthquake and 22.2% in the less intensive Lushan earthquake. The most frequent cause of chest injuries in both earthquakes was being accidentally struck. Injuries due to falls were less prevalent in the stronger Wenchuan earthquake, while injuries due to burial were more prevalent. The distribution of types of chest injury did not vary significantly between the two earthquakes, with rib fractures and pulmonary contusions the most frequent types. Spinal and head injuries concurrent with chest injuries were more prevalent in the less violent Lushan earthquake. All three trauma scoring systems showed poor ability to predict respiratory failure in patients with earthquake-related chest injuries. CONCLUSIONS: Previous studies may have underestimated the incidence of chest injury in violent earthquakes. The distributions of types of chest injury did not differ between these two earthquakes of different seismic intensity. Earthquake severity and interval between rescue and treatment may influence the prevalence and types of injuries that co-occur with the chest injury. Trauma evaluation scores on their own are inadequate predictors of respiratory failure in patients with earthquake

  15. On the agreement between small-world-like OFC model and real earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Douglas S.R., E-mail: [Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Paracambi, RJ (Brazil); Geophysics Department, Observatório Nacional, Rio de Janeiro, RJ (Brazil); Papa, Andrés R.R., E-mail: [Geophysics Department, Observatório Nacional, Rio de Janeiro, RJ (Brazil); Instituto de Física, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Menezes, Ronaldo, E-mail: [BioComplex Laboratory, Computer Sciences, Florida Institute of Technology, Melbourne (United States)


    In this article we implemented simulations of the OFC model for earthquakes for two different topologies: regular and small-world, where in the latter the links are randomly rewired with probability p. In both topologies, we have studied the distribution of time intervals between consecutive earthquakes and the border effects present in each one. In addition, we also have characterized the influence that the probability p produces in certain characteristics of the lattice and in the intensity of border effects. From the two topologies, networks of consecutive epicenters were constructed, that allowed us to analyze the distribution of connectivities of each one. In our results distributions arise belonging to a family of non-traditional distributions functions, which agrees with previous studies using data from actual earthquakes. Our results reinforce the idea that the Earth is in a critical self-organized state and furthermore point towards temporal and spatial correlations between earthquakes in different places. - Highlights: • OFC model simulations for regular and small-world topologies. • For small-world topology distributions agree remarkably well with actual earthquakes. • Reinforce the idea of a critical self-organized state for the Earth's crust. • Point towards temporal and spatial correlations between far earthquakes in far places.

  16. Forecast of Large Earthquakes Through Semi-periodicity Analysis of Labeled Point Processes (United States)

    Quinteros Cartaya, C. B.; Nava Pichardo, F. A.; Glowacka, E.; Gómez Treviño, E.; Dmowska, R.


    Large earthquakes have semi-periodic behavior as a result of critically self-organized processes of stress accumulation and release in seismogenic regions. Hence, large earthquakes in a given region constitute semi-periodic sequences with recurrence times varying slightly from periodicity. In previous papers, it has been shown that it is possible to identify these sequences through Fourier analysis of the occurrence time series of large earthquakes from a given region, by realizing that not all earthquakes in the region need belong to the same sequence, since there can be more than one process of stress accumulation and release in the region. Sequence identification can be used to forecast earthquake occurrence with well determined confidence bounds. This paper presents improvements on the above mentioned sequence identification and forecasting method: the influence of earthquake size on the spectral analysis, and its importance in semi-periodic events identification are considered, which means that earthquake occurrence times are treated as a labeled point process; a revised estimation of non-randomness probability is used; a better estimation of appropriate upper limit uncertainties to use in forecasts is introduced; and the use of Bayesian analysis to evaluate the posterior forecast performance is applied. This improved method was successfully tested on synthetic data and subsequently applied to real data from some specific regions. As an example of application, we show the analysis of data from the northeastern Japan Arc region, in which one semi-periodic sequence of four earthquakes with M ≥ 8.0, having high non-randomness probability was identified. We compare the results of this analysis with those of the unlabeled point process analysis.

  17. Modeling shallow slip deficit in large strike-slip earthquakes using simulations of spontaneous earthquake sequences in elasto-plastic media (United States)

    Kaneko, Y.; Fialko, Y.


    Slip inversions of several large strike-slip earthquakes point to coseismic slip deficit at shallow depths (Sierra El Mayor (Mexico) earthquake. Determining the origin of shallow slip deficit is important both for understanding physics of earthquakes and for estimating seismic hazard, as suppression of shallow rupture could greatly influence strong ground motion in the vicinity of active faults. Several mechanisms may be invoked to explain the deficit. A widely accepted interpretation is the presence of velocity-strengthening fault friction at shallow depths where the coseismic slip deficit is compensated by afterslip and interseismic creep. However, geodetic observations indicate that the occurrence of interseismic creep and afterslip at shallow depths is rather uncommon, except for certain locations near major creeping segments of mature faults and/or in areas with thick sedimentary covers with overpressurized pore fluids (e.g., Wei et al., 2009). Fialko et al. (2005) proposed that extensive inelastic failure of the shallow crust in the interseismic period or during earthquakes may result in coseismic slip deficit at shallow depths. In this work, we investigate whether inelastic failure of the shallow crust can lead to shallow coseismic slip deficit using simulations of spontaneous earthquake sequences on vertical planar strike-slip faults. To account for inelastic deformation, we incorporate off-fault plasticity into 2-D models of earthquake sequences on faults governed by laboratory-derived rate and state friction (Kaneko et al., 2010). Our preliminary results suggest that coseismic slip deficit could occur in a wide range of parameters that characterize inelastic material properties. We will report on our current efforts on identifying key parameters of fault friction and bulk rheology that link to the degree of coseismic slip deficit over multiple earthquake cycles.

  18. Historical Earthquakes in the Yellow Sea and Its Adjacent Area

    Institute of Scientific and Technical Information of China (English)

    Wu Ge; Wang Andong; Wu Di


    As a result of sorting out, estimating and cataloging of historical earthquakes, from the year of 2 A.D. to Aug., 1949, we found that there were 2187 earthquakes with M≥3.0 in the area of the Yellow Sea and its adjacent area. Among the earthquakes, the number of earthquakes with M ≥ 5.0 is 209, and at least 43 of the earthquakes caused serious losses, 20 of the earthquakes caused human causalities. It is demonstrated that there were 3 areas of historical earthquake concentration and the earthquake activity was higher in the 16th century and the first half if the 20th century.

  19. Earthquake Engineering Research Center: 25th anniversry edition (United States)


    The Earthquake Engineering Research Center exists to conduct research and develop technical information in all areas pertaining to earthquake engineering, including strong ground motion and ground failure, response of natural and manmade structures to earthquakes, design of structures to resist earthquakes, development of new systems for earthquake protection, and development of architectural and public policy aspects of earthquake engineering. The annual report for 1992-93 presents information on: Current Research Programs; Contracts and Grants; Public Service Program; National Information Service for Earthquake Engineering; Core Administration; Committees of the Earthquake Engineering Research Center; Research Participants - Faculty; and Research Participants - Students.

  20. Influence of soil strength on deformation and embedded depth of anti-slide pile in earthquake%地震中土体强度对抗滑桩变形和嵌固深度的影响

    Institute of Scientific and Technical Information of China (English)



    Aiming at different strength of debris landslides , we analyzed the response process of anti -slide pile reinforcing landslides with different soil strength under earthquake load through physical model test and numerical simulation .The results showed that anti-slide pile can better fulfill its performance with the increase of soil strength but with a certain amount of waste ;otherwise , the anti-sliding property would be declined .By utilizing the dynamic finite element process ANSYS , combined with dynamic analysis method of strengthreduction , we conclud and establish the calculation model and experience discrimination that consider the mutual effect of anchored depth and soil design strength cohesion force and internal friction angle .The design method and research mentality couldgive some references to related researches .%不同碎石土滑坡存在不同的强度差异。通过物理模型实验和数值模拟实验,分析了在地震荷载作用下不同土体强度抗滑桩支护滑坡的响应过程,得出:增大土体的强度,有利于发挥抗滑桩的抗滑作用,抗滑桩抗震效果较好,但是也存在一定程度的浪费;而减小土体强度,抗震效果并不好。利用ANSYS动力有限元程序,结合强度折减动力分析法,总结并建立了嵌固深度与土体强度设计值凝聚力、内摩擦角的相互作用计算模型和经验判别式。其设计方法和研究思路可为以后的相关研究提供借鉴和参考。

  1. Salient beliefs about earthquake hazards and household preparedness. (United States)

    Becker, Julia S; Paton, Douglas; Johnston, David M; Ronan, Kevin R


    Prior research has found little or no direct link between beliefs about earthquake risk and household preparedness. Furthermore, only limited work has been conducted on how people's beliefs influence the nature and number of preparedness measures adopted. To address this gap, 48 qualitative interviews were undertaken with residents in three urban locations in New Zealand subject to seismic risk. The study aimed to identify the diverse hazard and preparedness-related beliefs people hold and to articulate how these are influenced by public education to encourage preparedness. The study also explored how beliefs and competencies at personal, social, and environmental levels interact to influence people's risk management choices. Three main categories of beliefs were found: hazard beliefs; preparedness beliefs; and personal beliefs. Several salient beliefs found previously to influence the preparedness process were confirmed by this study, including beliefs related to earthquakes being an inevitable and imminent threat, self-efficacy, outcome expectancy, personal responsibility, responsibility for others, and beliefs related to denial, fatalism, normalization bias, and optimistic bias. New salient beliefs were also identified (e.g., preparedness being a "way of life"), as well as insight into how some of these beliefs interact within the wider informational and societal context.

  2. Intraplate triggered earthquakes: Observations and interpretation (United States)

    Hough, S.E.; Seeber, L.; Armbruster, J.G.


    We present evidence that at least two of the three 1811-1812 New Madrid, central United States, mainshocks and the 1886 Charleston, South Carolina, earthquake triggered earthquakes at regional distances. In addition to previously published evidence for triggered earthquakes in the northern Kentucky/southern Ohio region in 1812, we present evidence suggesting that triggered events might have occurred in the Wabash Valley, to the south of the New Madrid Seismic Zone, and near Charleston, South Carolina. We also discuss evidence that earthquakes might have been triggered in northern Kentucky within seconds of the passage of surface waves from the 23 January 1812 New Madrid mainshock. After the 1886 Charleston earthquake, accounts suggest that triggered events occurred near Moodus, Connecticut, and in southern Indiana. Notwithstanding the uncertainty associated with analysis of historical accounts, there is evidence that at least three out of the four known Mw 7 earthquakes in the central and eastern United States seem to have triggered earthquakes at distances beyond the typically assumed aftershock zone of 1-2 mainshock fault lengths. We explore the possibility that remotely triggered earthquakes might be common in low-strain-rate regions. We suggest that in a low-strain-rate environment, permanent, nonelastic deformation might play a more important role in stress accumulation than it does in interplate crust. Using a simple model incorporating elastic and anelastic strain release, we show that, for realistic parameter values, faults in intraplate crust remain close to their failure stress for a longer part of the earthquake cycle than do faults in high-strain-rate regions. Our results further suggest that remotely triggered earthquakes occur preferentially in regions of recent and/or future seismic activity, which suggests that faults are at a critical stress state in only some areas. Remotely triggered earthquakes may thus serve as beacons that identify regions of

  3. Spatial Evaluation and Verification of Earthquake Simulators (United States)

    Wilson, John Max; Yoder, Mark R.; Rundle, John B.; Turcotte, Donald L.; Schultz, Kasey W.


    In this paper, we address the problem of verifying earthquake simulators with observed data. Earthquake simulators are a class of computational simulations which attempt to mirror the topological complexity of fault systems on which earthquakes occur. In addition, the physics of friction and elastic interactions between fault elements are included in these simulations. Simulation parameters are adjusted so that natural earthquake sequences are matched in their scaling properties. Physically based earthquake simulators can generate many thousands of years of simulated seismicity, allowing for a robust capture of the statistical properties of large, damaging earthquakes that have long recurrence time scales. Verification of simulations against current observed earthquake seismicity is necessary, and following past simulator and forecast model verification methods, we approach the challenges in spatial forecast verification to simulators; namely, that simulator outputs are confined to the modeled faults, while observed earthquake epicenters often occur off of known faults. We present two methods for addressing this discrepancy: a simplistic approach whereby observed earthquakes are shifted to the nearest fault element and a smoothing method based on the power laws of the epidemic-type aftershock (ETAS) model, which distributes the seismicity of each simulated earthquake over the entire test region at a decaying rate with epicentral distance. To test these methods, a receiver operating characteristic plot was produced by comparing the rate maps to observed m>6.0 earthquakes in California since 1980. We found that the nearest-neighbor mapping produced poor forecasts, while the ETAS power-law method produced rate maps that agreed reasonably well with observations.

  4. Remotely triggered earthquakes following moderate main shocks (United States)

    Hough, S.E.


    Since 1992, remotely triggered earthquakes have been identified following large (M > 7) earthquakes in California as well as in other regions. These events, which occur at much greater distances than classic aftershocks, occur predominantly in active geothermal or volcanic regions, leading to theories that the earthquakes are triggered when passing seismic waves cause disruptions in magmatic or other fluid systems. In this paper, I focus on observations of remotely triggered earthquakes following moderate main shocks in diverse tectonic settings. I summarize evidence that remotely triggered earthquakes occur commonly in mid-continent and collisional zones. This evidence is derived from analysis of both historic earthquake sequences and from instrumentally recorded M5-6 earthquakes in eastern Canada. The latter analysis suggests that, while remotely triggered earthquakes do not occur pervasively following moderate earthquakes in eastern North America, a low level of triggering often does occur at distances beyond conventional aftershock zones. The inferred triggered events occur at the distances at which SmS waves are known to significantly increase ground motions. A similar result was found for 28 recent M5.3-7.1 earthquakes in California. In California, seismicity is found to increase on average to a distance of at least 200 km following moderate main shocks. This supports the conclusion that, even at distances of ???100 km, dynamic stress changes control the occurrence of triggered events. There are two explanations that can account for the occurrence of remotely triggered earthquakes in intraplate settings: (1) they occur at local zones of weakness, or (2) they occur in zones of local stress concentration. ?? 2007 The Geological Society of America.

  5. Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part B, historical earthquakes (United States)

    Wheeler, Russell L.


    Computation of probabilistic earthquake hazard requires an estimate of Mmax: the moment magnitude of the largest earthquake that is thought to be possible within a specified geographic region. The region specified in this report is the Central and Eastern United States and adjacent Canada. Parts A and B of this report describe the construction of a global catalog of moderate to large earthquakes that occurred worldwide in tectonic analogs of the Central and Eastern United States. Examination of histograms of the magnitudes of these earthquakes allows estimation of Central and Eastern United States Mmax. The catalog and Mmax estimates derived from it are used in the 2014 edition of the U.S. Geological Survey national seismic-hazard maps. Part A deals with prehistoric earthquakes, and this part deals with historical events.

  6. Diverse Approaches USED to Characterize the Earthquake and Tsunami Hazards Along the Southern Alaska Continental Margin (United States)

    Haeussler, P. J.; Witter, R. C.; Liberty, L. M.; Brothers, D. S.; Briggs, R. W.; Armstrong, P. A.; Freymueller, J. T.; Parsons, T.; Ryan, H. F.; Lee, H. J.; Roland, E. C.


    Earthquakes and tsunamis are the principal geohazards of southern Alaska. The entire margin has ruptured in megathrust earthquakes, including the M9.2 1964 event, and these earthquakes have launched deadly local and trans-Pacific tsunamis. Tsunamis have been by far the largest killer in these earthquakes. Moreover, the subduction zone displays a range in locking behavior from completely locked beneath Prince William Sound, to ­­­­nearly freely slipping beneath the Shumagin Islands. Characterizing earthquake-related tsunami sources requires a diverse set of methods, and we discuss several examples. One important source for tsunamis is from megathrust splay faults. The Patton Bay splay fault system ruptured during the 1964 earthquake and generated a tsunami that impacted coastlines tens of minutes after the earthquake. A combination of multibeam mapping, high-resolution and crustal-scale seismic data, thermochronology, and detrital zircon geochronology show focused exhumation along this splay fault system for the last 2-3 Ma. Moreover, this long term pattern of exhumation mimics the pattern of uplift in 1964. Submarine landslides are another example of a tsunami source. Numerous devastating slides were triggered by the 1964 earthquake. Multibeam bathymetry, bathymetry difference maps, high-resolution seismic data, and records of paleotsunamis in coastal marshes reveal a long history of submarine landsliding in the coastal fjords of Alaska. The Little Ice Age appears to have had a significant influence on the submarine landslides in the 1964 earthquake through increased sediment production, transport to fjord margins, and, locally, compaction by glacier advances. Glacial retreat before 1964 gave rise to over-steepened slopes susceptible to dynamic failure. Numerous blocks in the submarine landslides were particularly effective in generating high tsunami run up. Finally, regional tectonic displacements of the seafloor have launched trans-Pacific tsunamis. Coastal

  7. Modeling earthquake indexes derived from the earthquake warning system upon the planet earth

    Institute of Scientific and Technical Information of China (English)


    By studying the correlation between historical earthquake data and the distributional characteristics of parameters of solid earth tides in the earthquake epicenter, we are able to design a forecasting function of earthquake probability. We put forward a design method for the Earthquake Warning System. The model could theoretically simulate and be used to predict the probability of strong earthquakes that could occur anywhere at any time. In addition, the system could also conveniently obtain global or partial Modeling Earthquake Indexes to finally combine the precise pointing prediction and forecast of partial indexes. The literature quotes global data values, provided by NEIC, of 1544 M ≥ 6.5 earthquakes. It also gives examples of instantaneous earthquake indexes of the whole world and Taiwan Area on 1st January 2010, UT=0:00 and the average earthquake index near the Taiwan Area. According to the 10-year pointing prediction of strong earthquakes in San Francisco, the literature provides the average earthquake index on 24th June 2015 (± 15 days), in its neighborhood.

  8. Results of the Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California. (United States)

    Lee, Ya-Ting; Turcotte, Donald L; Holliday, James R; Sachs, Michael K; Rundle, John B; Chen, Chien-Chih; Tiampo, Kristy F


    The Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California was the first competitive evaluation of forecasts of future earthquake occurrence. Participants submitted expected probabilities of occurrence of M ≥ 4.95 earthquakes in 0.1° × 0.1° cells for the period 1 January 1, 2006, to December 31, 2010. Probabilities were submitted for 7,682 cells in California and adjacent regions. During this period, 31 M ≥ 4.95 earthquakes occurred in the test region. These earthquakes occurred in 22 test cells. This seismic activity was dominated by earthquakes associated with the M = 7.2, April 4, 2010, El Mayor-Cucapah earthquake in northern Mexico. This earthquake occurred in the test region, and 16 of the other 30 earthquakes in the test region could be associated with it. Nine complete forecasts were submitted by six participants. In this paper, we present the forecasts in a way that allows the reader to evaluate which forecast is the most "successful" in terms of the locations of future earthquakes. We conclude that the RELM test was a success and suggest ways in which the results can be used to improve future forecasts.

  9. Modeling earthquake indexes derived from the earthquake warning system upon the planet earth (United States)

    Li, Yong


    By studying the correlation between historical earthquake data and the distributional characteristics of parameters of solid earth tides in the earthquake epicenter, we are able to design a forecasting function of earthquake probability. We put forward a design method for the Earthquake Warning System. The model could theoretically simulate and be used to predict the probability of strong earthquakes that could occur anywhere at any time. In addition, the system could also conveniently obtain global or partial Modeling Earthquake Indexes to finally combine the precise pointing prediction and forecast of partial indexes. The literature quotes global data values, provided by NEIC, of 1544 M ⩾ 6.5 earthquakes. It also gives examples of instantaneous earthquake indexes of the whole world and Taiwan Area on 1st January 2010, UT=0:00 and the average earthquake index near the Taiwan Area. According to the 10-year pointing prediction of strong earthquakes in San Francisco, the literature provides the average earthquake index on 24th June 2015 (± 15 days), in its neighborhood.

  10. Putting down roots in earthquake country-Your handbook for earthquakes in the Central United States (United States)

    Contributors: Dart, Richard; McCarthy, Jill; McCallister, Natasha; Williams, Robert A.


    This handbook provides information to residents of the Central United States about the threat of earthquakes in that area, particularly along the New Madrid seismic zone, and explains how to prepare for, survive, and recover from such events. It explains the need for concern about earthquakes for those residents and describes what one can expect during and after an earthquake. Much is known about the threat of earthquakes in the Central United States, including where they are likely to occur and what can be done to reduce losses from future earthquakes, but not enough has been done to prepare for future earthquakes. The handbook describes such preparations that can be taken by individual residents before an earthquake to be safe and protect property.

  11. Research on strong earthquake type division and forecast method for subsequent strong earthquakes

    Institute of Scientific and Technical Information of China (English)


    The relationships between energy, amplitude and frequency of earthquake are correlative with the property of the seismic source. And the grade of the correlativity can be used as an index to distinguish the types of strong earthquakes. Primarily the strong earthquake can be divided into three types of main-after earthquakes, double-main earthquakes and swarm of strong earthquake. There are similarity and a certain repeatability at the quantificational indexes of hypocenter property between the same type of strong earthquakes, which supply basis for the forecast of subsequent strong shocks. The reference indexes of after strong shock forecast which are valuable for the applications of the method of type-divided forecast come from the analysis about more than fifty strong shock wide-band (BPZ wave) recording data of CDSN from 1988 to 1997.

  12. Earthquakes in the Pamplona zone, Yakutat block, south central Alaska (United States)

    Doser, Diane I.; Pelton, John R.; Veilleux, Annette M.


    The Pamplona zone is a region of complex deformation and moderate seismicity located within the Yakutat block, a region that has been relatively aseismic since a series of large (M>7.8) earthquakes in 1899. In 1970 a sequence of moderate to large sized earthquakes occurred within the Pamplona zone (largest event of Mw=6.7). Together with a Mw=6.1 event in 1958, these events are the only M≥5.5 events known to have occurred in the Pamplona region since 1900. Thus these events give important information on internal deformational processes within the Yakutat block. Waveform modeling of three earthquakes in April 1970, showed rupture complexity along low angle, thrust faults. Focal depths indicate that two of the events occurred above the Wrangell-Aleutian megathrust, while the largest event may have occurred on the megathrust. Events in 1958 and February 1970 indicate that deformation within the western Pamplona zone is occurring along high angle (>60°) faults with reverse-oblique motion. We believe the Pamplona spur, the easternmost part of the Pamplona zone, may have behaved as an asperity during the 1899 sequence. The location of the spur may be influenced by a north-south trending fault zone in the subducting Pacific plate that appears to be responsible for the 1987-1992 Gulf of Alaska sequence, occurring 50 to 200 km south of the Pamplona zone.

  13. Biological Anomalies around the 2009 L'Aquila Earthquake. (United States)

    Fidani, Cristiano


    The April 6, 2009 L'Aquila earthquake was the strongest seismic event to occur in Italy over the last thirty years with a magnitude of M = 6.3. Around the time of the seismic swarm many instruments were operating in Central Italy, even if not dedicated to biological effects associated with the stress field variations, including seismicity. Testimonies were collected using a specific questionnaire immediately after the main shock, including data on earthquake lights, gas leaks, human diseases, and irregular animal behavior. The questionnaire was made up of a sequence of arguments, based upon past historical earthquake observations and compiled over seven months after the main shock. Data on animal behavior, before, during and after the main shocks, were analyzed in space/time distributions with respect to the epicenter area, evidencing the specific responses of different animals. Several instances of strange animal behavior were observed which could causally support the hypotheses that they were induced by the physical presence of gas, electric charges and electromagnetic waves in atmosphere. The aim of this study was to order the biological observations and thereby allow future work to determine whether these observations were influenced by geophysical parameters.

  14. Estimation of earthquake risk curves of physical building damage (United States)

    Raschke, Mathias; Janouschkowetz, Silke; Fischer, Thomas; Simon, Christian


    In this study, a new approach to quantify seismic risks is presented. Here, the earthquake risk curves for the number of buildings with a defined physical damage state are estimated for South Africa. Therein, we define the physical damage states according to the current European macro-seismic intensity scale (EMS-98). The advantage of such kind of risk curve is that its plausibility can be checked more easily than for other types. The earthquake risk curve for physical building damage can be compared with historical damage and their corresponding empirical return periods. The number of damaged buildings from historical events is generally explored and documented in more detail than the corresponding monetary losses. The latter are also influenced by different economic conditions, such as inflation and price hikes. Further on, the monetary risk curve can be derived from the developed risk curve of physical building damage. The earthquake risk curve can also be used for the validation of underlying sub-models such as the hazard and vulnerability modules.

  15. GEM - The Global Earthquake Model (United States)

    Smolka, A.


    Over 500,000 people died in the last decade due to earthquakes and tsunamis, mostly in the developing world, where the risk is increasing due to rapid population growth. In many seismic regions, no hazard and risk models exist, and even where models do exist, they are intelligible only by experts, or available only for commercial purposes. The Global Earthquake Model (GEM) answers the need for an openly accessible risk management tool. GEM is an internationally sanctioned public private partnership initiated by the Organisation for Economic Cooperation and Development (OECD) which will establish an authoritative standard for calculating and communicating earthquake hazard and risk, and will be designed to serve as the critical instrument to support decisions and actions that reduce earthquake losses worldwide. GEM will integrate developments on the forefront of scientific and engineering knowledge of earthquakes, at global, regional and local scale. The work is organized in three modules: hazard, risk, and socio-economic impact. The hazard module calculates probabilities of earthquake occurrence and resulting shaking at any given location. The risk module calculates fatalities, injuries, and damage based on expected shaking, building vulnerability, and the distribution of population and of exposed values and facilities. The socio-economic impact module delivers tools for making educated decisions to mitigate and manage risk. GEM will be a versatile online tool, with open source code and a map-based graphical interface. The underlying data will be open wherever possible, and its modular input and output will be adapted to multiple user groups: scientists and engineers, risk managers and decision makers in the public and private sectors, and the public-at- large. GEM will be the first global model for seismic risk assessment at a national and regional scale, and aims to achieve broad scientific participation and independence. Its development will occur in a

  16. Earthquake precursory research in western Himalaya based on the multi-parametric geophysical observatory data (United States)

    Kumar, Naresh; Rawat, Gautam; Choubey, Vinay; Hazarika, Devajit


    The opening of cracks and influx of fluids in the dilatancy zone of impending earthquake is expected to induce short-term changes in physical/chemical/hydrological properties during earthquake build-up cycle, which should be reflected in time-varying geophysical fields. With this rationale, eleven geophysical parameters are being recorded in continuous mode at the Multi-Parametric Geophysical Observatory (MPGO), in Ghuttu, Garhwal Himalaya, for earthquake precursory research. The critical analysis of various geophysical time series indicates anomalous behavior at few occasions; however, the data is also influenced by many external forces. These external influences are the major deterrent for the isolation of precursory signals. The recent work is focused on the data adoptive techniques to estimate and eliminate effects of solar-terrestrial and hydrological/environmental factors for delimiting the data to identify short-term precursors. Although any significant earthquake is not reported close to the observatory, some weak precursory signals and coseismic changes have been identified in few parameters related to the occurrence of moderate and strong earthquakes.

  17. Napa Earthquake impact on water systems (United States)

    Wang, J.


    South Napa earthquake occurred in Napa, California on August 24 at 3am, local time, and the magnitude is 6.0. The earthquake was the largest in SF Bay Area since the 1989 Loma Prieta earthquake. Economic loss topped $ 1 billion. Wine makers cleaning up and estimated the damage on tourism. Around 15,000 cases of lovely cabernet were pouring into the garden at the Hess Collection. Earthquake potentially raise water pollution risks, could cause water crisis. CA suffered water shortage recent years, and it could be helpful on how to prevent underground/surface water pollution from earthquake. This research gives a clear view on drinking water system in CA, pollution on river systems, as well as estimation on earthquake impact on water supply. The Sacramento-San Joaquin River delta (close to Napa), is the center of the state's water distribution system, delivering fresh water to more than 25 million residents and 3 million acres of farmland. Delta water conveyed through a network of levees is crucial to Southern California. The drought has significantly curtailed water export, and salt water intrusion reduced fresh water outflows. Strong shaking from a nearby earthquake can cause saturated, loose, sandy soils liquefaction, and could potentially damage major delta levee systems near Napa. Napa earthquake is a wake-up call for Southern California. It could potentially damage freshwater supply system.

  18. Triggering of repeating earthquakes in central California (United States)

    Wu, Chunquan; Gomberg, Joan; Ben-Naim, Eli; Johnson, Paul


    Dynamic stresses carried by transient seismic waves have been found capable of triggering earthquakes instantly in various tectonic settings. Delayed triggering may be even more common, but the mechanisms are not well understood. Catalogs of repeating earthquakes, earthquakes that recur repeatedly at the same location, provide ideal data sets to test the effects of transient dynamic perturbations on the timing of earthquake occurrence. Here we employ a catalog of 165 families containing ~2500 total repeating earthquakes to test whether dynamic perturbations from local, regional, and teleseismic earthquakes change recurrence intervals. The distance to the earthquake generating the perturbing waves is a proxy for the relative potential contributions of static and dynamic deformations, because static deformations decay more rapidly with distance. Clear changes followed the nearby 2004 Mw6 Parkfield earthquake, so we study only repeaters prior to its origin time. We apply a Monte Carlo approach to compare the observed number of shortened recurrence intervals following dynamic perturbations with the distribution of this number estimated for randomized perturbation times. We examine the comparison for a series of dynamic stress peak amplitude and distance thresholds. The results suggest a weak correlation between dynamic perturbations in excess of ~20 kPa and shortened recurrence intervals, for both nearby and remote perturbations.

  19. Stress,strain and earthquake activity

    Institute of Scientific and Technical Information of China (English)

    Yaolin Shi


    @@ There are 13 papers in this special issue on stress field,crustal deformation and seismicity.The great Wenchuan earthquake is a grievous disaster,but Chinese scientists are trying to learn more from the event in order to understand better the physics of earthquakes for future hazard mitigation planning.

  20. Forecasting characteristic earthquakes in a minimalist model

    DEFF Research Database (Denmark)

    Vázquez-Prada, M.; Pacheco, A.; González, Á.


    Using error diagrams, we quantify the forecasting of characteristic-earthquake occurence in a recently introduced minimalist model. Initially we connect the earthquake alarm at a fixed time after the occurence of a characteristic event. The evaluation of this strategy leads to a one-dimensional n...

  1. Wood-framed houses for earthquake zones

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg

    Wood-framed houses with a sheathing are suitable for use in earthquake zones. The Direction describes a method of determining the earthquake forces in a house and shows how these forces can be resisted by diaphragm action in the walls, floors, and roof, of the house. An appendix explains how...

  2. A minimalist model of characteristic earthquakes

    DEFF Research Database (Denmark)

    Vázquez-Prada, M.; González, Á.; Gómez, J.B.;


    -earthquake behaviour of some seismic faults. This model, that has no parameter, is amenable to an algebraic description as a Markov Chain. This possibility illuminates some important results, obtained by Monte Carlo simulations, such as the earthquake size-frequency relation and the recurrence time...

  3. Acoustic wave-equation-based earthquake location (United States)

    Tong, Ping; Yang, Dinghui; Liu, Qinya; Yang, Xu; Harris, Jerry


    We present a novel earthquake location method using acoustic wave-equation-based traveltime inversion. The linear relationship between the location perturbation (δt0, δxs) and the resulting traveltime residual δt of a particular seismic phase, represented by the traveltime sensitivity kernel K(t0, xs) with respect to the earthquake location (t0, xs), is theoretically derived based on the adjoint method. Traveltime sensitivity kernel K(t0, xs) is formulated as a convolution between the forward and adjoint wavefields, which are calculated by numerically solving two acoustic wave equations. The advantage of this newly derived traveltime kernel is that it not only takes into account the earthquake-receiver geometry but also accurately honours the complexity of the velocity model. The earthquake location is obtained by solving a regularized least-squares problem. In 3-D realistic applications, it is computationally expensive to conduct full wave simulations. Therefore, we propose a 2.5-D approach which assumes the forward and adjoint wave simulations within a 2-D vertical plane passing through the earthquake and receiver. Various synthetic examples show the accuracy of this acoustic wave-equation-based earthquake location method. The accuracy and efficiency of the 2.5-D approach for 3-D earthquake location are further verified by its application to the 2004 Big Bear earthquake in Southern California.

  4. Earthquakes: Risk, Detection, Warning, and Research (United States)


    and central China, and as far away as Bangladesh , Taiwan, Thailand, and Vietnam. Several large aftershocks occurred after the main seismic event...34 The number of stations necessary to generate a data-based ShakeMap depends on the urban area and geology ...Research Congressional Research Service 24 • Earthquake geology and paleoseismology: studies of the history, effects, and mechanics of earthquakes

  5. Structural Earthquake Resistance Design Using Energy Method

    Institute of Scientific and Technical Information of China (English)

    Hu Rongrong


    A summary of status of researches in the field of structural earthquake resistance design on energy concept is presented in three parts: earthquake input, demands on the structure and supplied capacity of the structure. A new approach is proposed for analysis of the seismic response and damage criteria based on the momentary input energy.

  6. The 2010 Haiti earthquake response. (United States)

    Raviola, Giuseppe; Severe, Jennifer; Therosme, Tatiana; Oswald, Cate; Belkin, Gary; Eustache, Eddy


    This article presents an overview of the mental health response to the 2010 Haiti earthquake. Discussion includes consideration of complexities that relate to emergency response, mental health and psychosocial response in disasters, long-term planning of systems of care, and the development of safe, effective, and culturally sound mental health services in the Haitian context. This information will be of value to mental health professionals and policy specialists interested in mental health in Haiti, and in the delivery of mental health services in particularly resource-limited contexts in the setting of disasters.

  7. Earthquake Effects on Employee Transportation


    Bennett, Anna K; Little, David D.


    The Loma Prieta earthquake of October 17, 1989, had a disastrous impact on surface transportation in the Bay Area. The most tragic effect of the failures in the transportation system was the loss of life in the collapse of the Cypress structure on Interstate 880 in Oakland and of the section of the Bay Bridge. Less dramatic, but disrupting the daily routines of thousands of commuters, were the traffic delays and congestion that occurred in the month that the Bay Bridge and Highway 17 (between...

  8. Statistical properties of earthquakes clustering

    Directory of Open Access Journals (Sweden)

    A. Vecchio


    Full Text Available Often in nature the temporal distribution of inhomogeneous stochastic point processes can be modeled as a realization of renewal Poisson processes with a variable rate. Here we investigate one of the classical examples, namely, the temporal distribution of earthquakes. We show that this process strongly departs from a Poisson statistics for both catalogue and sequence data sets. This indicate the presence of correlations in the system probably related to the stressing perturbation characterizing the seismicity in the area under analysis. As shown by this analysis, the catalogues, at variance with sequences, show common statistical properties.

  9. Inference of postseismic deformation mechanisms of the 1923 Kanto earthquake (United States)

    Pollitz, F.F.; Nyst, M.; Nishimura, T.; Thatcher, W.


    stress pattern. This suggests that the influence of the 1923 earthquake on regional seismicity is fairly predictable and has persisted for at least seven decades following the earthquake.

  10. Earthquake Correlations and Networks- A Comparative Study

    CERN Document Server

    G., T R Krishna Mohan P


    We quantify the correlation between earthquakes and use the same to distinguish between relevant causally connected earthquakes. Our correlation metric is a variation on the one introduced by Baiesi and Paczuski (2004). A network of earthquakes is constructed, which is time ordered and with links between the more correlated ones. Recurrences to earthquakes are identified employing correlation thresholds to demarcate the most meaningful ones in each cluster. Data pertaining to three different seismic regions, viz. California, Japan and Himalayas, are comparatively analyzed using such a network model. The distribution of recurrence lengths and recurrence times are two of the key features analyzed to draw conclusions about the universal aspects of such a network model. We find that the unimodal feature of recurrence length distribution, which helps to associate typical rupture lengths with different magnitude earthquakes, is robust across the different seismic regions. The out-degree of the networks shows a hub ...

  11. Parallelization of the Coupled Earthquake Model (United States)

    Block, Gary; Li, P. Peggy; Song, Yuhe T.


    This Web-based tsunami simulation system allows users to remotely run a model on JPL s supercomputers for a given undersea earthquake. At the time of this reporting, predicting tsunamis on the Internet has never happened before. This new code directly couples the earthquake model and the ocean model on parallel computers and improves simulation speed. Seismometers can only detect information from earthquakes; they cannot detect whether or not a tsunami may occur as a result of the earthquake. When earthquake-tsunami models are coupled with the improved computational speed of modern, high-performance computers and constrained by remotely sensed data, they are able to provide early warnings for those coastal regions at risk. The software is capable of testing NASA s satellite observations of tsunamis. It has been successfully tested for several historical tsunamis, has passed all alpha and beta testing, and is well documented for users.

  12. Stochastic Differential Equation of Earthquakes Series (United States)

    Mariani, Maria C.; Tweneboah, Osei K.; Gonzalez-Huizar, Hector; Serpa, Laura


    This work is devoted to modeling earthquake time series. We propose a stochastic differential equation based on the superposition of independent Ornstein-Uhlenbeck processes driven by a Γ (α, β ) process. Superposition of independent Γ (α, β ) Ornstein-Uhlenbeck processes offer analytic flexibility and provides a class of continuous time processes capable of exhibiting long memory behavior. The stochastic differential equation is applied to the study of earthquakes by fitting the superposed Γ (α, β ) Ornstein-Uhlenbeck model to earthquake sequences in South America containing very large events (Mw ≥ 8). We obtained very good fit of the observed magnitudes of the earthquakes with the stochastic differential equations, which supports the use of this methodology for the study of earthquakes sequence.

  13. Antioptimization of earthquake exitation and response

    Directory of Open Access Journals (Sweden)

    G. Zuccaro


    Full Text Available The paper presents a novel approach to predict the response of earthquake-excited structures. The earthquake excitation is expanded in terms of series of deterministic functions. The coefficients of the series are represented as a point in N-dimensional space. Each available ccelerogram at a certain site is then represented as a point in the above space, modeling the available fragmentary historical data. The minimum volume ellipsoid, containing all points, is constructed. The ellipsoidal models of uncertainty, pertinent to earthquake excitation, are developed. The maximum response of a structure, subjected to the earthquake excitation, within ellipsoidal modeling of the latter, is determined. This procedure of determining least favorable response was termed in the literature (Elishakoff, 1991 as an antioptimization. It appears that under inherent uncertainty of earthquake excitation, antioptimization analysis is a viable alternative to stochastic approach.

  14. [Environmental security in the region with heavy exposure to sources of man-made earthquakes]. (United States)

    Kharlamova, E V; Shmandiĭ, V M; Gal'chuk, S V


    It is set that in separate regions substantial value at the study of terms of forming of ecological danger it is necessary to spare to research of vibrations of earth surface under effect of technogenic activity of man. Influence of technogenic earthquakes is investigational on a man and dwellings apartments medical and other establishments. Levels are set also intensities resulting in psychological discomfort.

  15. Theory of earthquakes interevent times applied to financial markets

    CERN Document Server

    Jagielski, Maciej; Sornette, Didier


    We analyze the probability density function (PDF) of waiting times between financial loss exceedances. The empirical PDFs are fitted with the self-excited Hawkes conditional Poisson process with a long power law memory kernel. The Hawkes process the simplest extension of the Poisson process that takes into account how past events influence the occurrence of future events. By analyzing the empirical data for 15 different financial assets, we show that the formalism of the Hawkes process used for earthquakes can successfully model the PDF of interevent times between successive market losses.

  16. Ground motion modeling of the 1906 San Francisco earthquake II: Ground motion estimates for the 1906 earthquake and scenario events

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, B; Brocher, T; Dreger, D; Frankel, A; Graves, R; Harmsen, S; Hartzell, S; Larsen, S; McCandless, K; Nilsson, S; Petersson, N A; Rodgers, A; Sjogreen, B; Tkalcic, H; Zoback, M L


    We estimate the ground motions produced by the 1906 San Francisco earthquake making use of the recently developed Song et al. (2008) source model that combines the available geodetic and seismic observations and recently constructed 3D geologic and seismic velocity models. Our estimates of the ground motions for the 1906 earthquake are consistent across five ground-motion modeling groups employing different wave propagation codes and simulation domains. The simulations successfully reproduce the main features of the Boatwright and Bundock (2005) ShakeMap, but tend to over predict the intensity of shaking by 0.1-0.5 modified Mercalli intensity (MMI) units. Velocity waveforms at sites throughout the San Francisco Bay Area exhibit characteristics consistent with rupture directivity, local geologic conditions (e.g., sedimentary basins), and the large size of the event (e.g., durations of strong shaking lasting tens of seconds). We also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern San Andreas fault, considering three additional hypocenters and an additional, random distribution of slip. Rupture directivity exerts the strongest influence on the variations in shaking, although sedimentary basins do consistently contribute to the response in some locations, such as Santa Rosa, Livermore, and San Jose. These scenarios suggest that future large earthquakes on the northern San Andreas fault may subject the current San Francisco Bay urban area to stronger shaking than a repeat of the 1906 earthquake. Ruptures propagating southward towards San Francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward.

  17. Normal fault earthquakes or graviquakes (United States)

    Doglioni, C.; Carminati, E.; Petricca, P.; Riguzzi, F.


    Earthquakes are dissipation of energy throughout elastic waves. Canonically is the elastic energy accumulated during the interseismic period. However, in crustal extensional settings, gravity is the main energy source for hangingwall fault collapsing. Gravitational potential is about 100 times larger than the observed magnitude, far more than enough to explain the earthquake. Therefore, normal faults have a different mechanism of energy accumulation and dissipation (graviquakes) with respect to other tectonic settings (strike-slip and contractional), where elastic energy allows motion even against gravity. The bigger the involved volume, the larger is their magnitude. The steeper the normal fault, the larger is the vertical displacement and the larger is the seismic energy released. Normal faults activate preferentially at about 60° but they can be shallower in low friction rocks. In low static friction rocks, the fault may partly creep dissipating gravitational energy without releasing great amount of seismic energy. The maximum volume involved by graviquakes is smaller than the other tectonic settings, being the activated fault at most about three times the hypocentre depth, explaining their higher b-value and the lower magnitude of the largest recorded events. Having different phenomenology, graviquakes show peculiar precursors. PMID:26169163

  18. Characterisation of Liquefaction Effects for Beyond-Design Basis Safety Assessment of Nuclear Power Plants (United States)

    Bán, Zoltán; Győri, Erzsébet; János Katona, Tamás; Tóth, László


    Preparedness of nuclear power plants to beyond design base external effects became high importance after 11th of March 2011 Great Tohoku Earthquakes. In case of some nuclear power plants constructed at the soft soil sites, liquefaction should be considered as a beyond design basis hazard. The consequences of liquefaction have to be analysed with the aim of definition of post-event plant condition, identification of plant vulnerabilities and planning the necessary measures for accident management. In the paper, the methodology of the analysis of liquefaction effects for nuclear power plants is outlined. The case of Nuclear Power Plant at Paks, Hungary is used as an example for demonstration of practical importance of the presented results and considerations. Contrary to the design, conservatism of the methodology for the evaluation of beyond design basis liquefaction effects for an operating plant has to be limited to a reasonable level. Consequently, applicability of all existing methods has to be considered for the best estimation. The adequacy and conclusiveness of the results is mainly limited by the epistemic uncertainty of the methods used for liquefaction hazard definition and definition of engineering parameters characterizing the consequences of liquefaction. The methods have to comply with controversial requirements. They have to be consistent and widely accepted and used in the practice. They have to be based on the comprehensive database. They have to provide basis for the evaluation of dominating engineering parameters that control the post-liquefaction response of the plant structures. Experience of Kashiwazaki-Kariwa plant hit by Niigata-ken Chuetsu-oki earthquake of 16 July 2007 and analysis of site conditions and plant layout at Paks plant have shown that the differential settlement is found to be the dominating effect in case considered. They have to be based on the probabilistic seismic hazard assessment and allow the integration into logic

  19. Probabilistic approach to earthquake prediction.

    Directory of Open Access Journals (Sweden)

    G. D'Addezio


    Full Text Available The evaluation of any earthquake forecast hypothesis requires the application of rigorous statistical methods. It implies a univocal definition of the model characterising the concerned anomaly or precursor, so as it can be objectively recognised in any circumstance and by any observer.A valid forecast hypothesis is expected to maximise successes and minimise false alarms. The probability gain associated to a precursor is also a popular way to estimate the quality of the predictions based on such precursor. Some scientists make use of a statistical approach based on the computation of the likelihood of an observed realisation of seismic events, and on the comparison of the likelihood obtained under different hypotheses. This method can be extended to algorithms that allow the computation of the density distribution of the conditional probability of earthquake occurrence in space, time and magnitude. Whatever method is chosen for building up a new hypothesis, the final assessment of its validity should be carried out by a test on a new and independent set of observations. The implementation of this test could, however, be problematic for seismicity characterised by long-term recurrence intervals. Even using the historical record, that may span time windows extremely variable between a few centuries to a few millennia, we have a low probability to catch more than one or two events on the same fault. Extending the record of earthquakes of the past back in time up to several millennia, paleoseismology represents a great opportunity to study how earthquakes recur through time and thus provide innovative contributions to time-dependent seismic hazard assessment. Sets of paleoseimologically dated earthquakes have been established for some faults in the Mediterranean area: the Irpinia fault in Southern Italy, the Fucino fault in Central Italy, the El Asnam fault in Algeria and the Skinos fault in Central Greece. By using the age of the

  20. Understanding earthquake hazards in urban areas - Evansville Area Earthquake Hazards Mapping Project (United States)

    Boyd, Oliver S.


    The region surrounding Evansville, Indiana, has experienced minor damage from earthquakes several times in the past 200 years. Because of this history and the proximity of Evansville to the Wabash Valley and New Madrid seismic zones, there is concern among nearby communities about hazards from earthquakes. Earthquakes currently cannot be predicted, but scientists can estimate how strongly the ground is likely to shake as a result of an earthquake and are able to design structures to withstand this estimated ground shaking. Earthquake-hazard maps provide one way of conveying such information and can help the region of Evansville prepare for future earthquakes and reduce earthquake-caused loss of life and financial and structural loss. The Evansville Area Earthquake Hazards Mapping Project (EAEHMP) has produced three types of hazard maps for the Evansville area: (1) probabilistic seismic-hazard maps show the ground motion that is expected to be exceeded with a given probability within a given period of time; (2) scenario ground-shaking maps show the expected shaking from two specific scenario earthquakes; (3) liquefaction-potential maps show how likely the strong ground shaking from the scenario earthquakes is to produce liquefaction. These maps complement the U.S. Geological Survey's National Seismic Hazard Maps but are more detailed regionally and take into account surficial geology, soil thickness, and soil stiffness; these elements greatly affect ground shaking.

  1. Are Earthquakes Predictable? A Study on Magnitude Correlations in Earthquake Catalog and Experimental Data (United States)

    Stavrianaki, K.; Ross, G.; Sammonds, P. R.


    The clustering of earthquakes in time and space is widely accepted, however the existence of correlations in earthquake magnitudes is more questionable. In standard models of seismic activity, it is usually assumed that magnitudes are independent and therefore in principle unpredictable. Our work seeks to test this assumption by analysing magnitude correlation between earthquakes and their aftershocks. To separate mainshocks from aftershocks, we perform stochastic declustering based on the widely used Epidemic Type Aftershock Sequence (ETAS) model, which allows us to then compare the average magnitudes of aftershock sequences to that of their mainshock. The results of earthquake magnitude correlations were compared with acoustic emissions (AE) from laboratory analog experiments, as fracturing generates both AE at the laboratory scale and earthquakes on a crustal scale. Constant stress and constant strain rate experiments were done on Darley Dale sandstone under confining pressure to simulate depth of burial. Microcracking activity inside the rock volume was analyzed by the AE technique as a proxy for earthquakes. Applying the ETAS model to experimental data allowed us to validate our results and provide for the first time a holistic view on the correlation of earthquake magnitudes. Additionally we search the relationship between the conditional intensity estimates of the ETAS model and the earthquake magnitudes. A positive relation would suggest the existence of magnitude correlations. The aim of this study is to observe any trends of dependency between the magnitudes of aftershock earthquakes and the earthquakes that trigger them.

  2. Study on the Sliding Displacement of a Sliding Structure Subjected to Multi-directional Earthquake Excitation

    Institute of Scientific and Technical Information of China (English)

    Fan Aiwu; Tang Jiaxiang; Li Li; Yang Jun


    Transient dynamic analysis is used to study the effect of the bidirectional interaction of friction on the response of sliding displacement of a sliding structure subjected to bidirectional earthquake ground motion. The analysis varies the parameters of amplitude ratio of earthquake excitation, the period of the superstructure, and the coefficient of friction in the sliding support. Numerical results show that the sliding structure is significantly influenced by the interaction of frictional forces. So the sliding displacement may be underestimated and the acceleration of the superstructure may be overrated if the bidirectional interaction of frictional forces is neglected.

  3. Ice Mass Fluctuations and Earthquake Hazard (United States)

    Sauber, J.


    evaluating the influence of ice mass changes since the end of the little Ice Age, the study is partially motivated by paleoseismic evidence from Yakataga and Kodiak regions which suggests that earlier glacier retreat may be associated with large earthquakes [Sauber et al., 2000; Carver et al., 2003].

  4. Seismicity prior to the 2016 Kumamoto earthquakes

    CERN Document Server

    Nanjo, K Z; Orihara, Y; Furuse, N; Togo, S; Nitta, H; Okada, T; Tanaka, R; Kamogawa, M; Nagao, T


    The 2016 Kumamoto earthquakes occurred under circumstance that seismicity remains high in all parts of Japan since the 2011 Tohoku-Oki earthquake. Identifying what happened before this incident is one starting point for promote earthquake forecast research to prepare for subsequent large earthquakes in the near future in Japan. Here we report precursory seismic patterns prior to the Kumamoto earthquakes, measured by four different methods based on seismicity changes that can be used for earthquake forecasting: b-value method, two kinds of seismic quiescence evaluation methods, and a method of detailed foreshock evaluation. The spatial extent of precursory patterns differs from one method to the other and ranges from local scales (typically asperity size), to regional scales (e.g., 2{\\deg} x 3{\\deg} around the source zone). The earthquakes are preceded by periods of pronounced anomalies, which lasted decade scales (e.g., 20 years or longer) to yearly scales (e.g., 1~2 years). We demonstrate that combination of...

  5. New geological perspectives on earthquake recurrence models

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, D.P. [Geological Survey, Menlo Park, CA (United States)


    In most areas of the world the record of historical seismicity is too short or uncertain to accurately characterize the future distribution of earthquakes of different sizes in time and space. Most faults have not ruptured once, let alone repeatedly. Ultimately, the ability to correctly forecast the magnitude, location, and probability of future earthquakes depends on how well one can quantify the past behavior of earthquake sources. Paleoseismological trenching of active faults, historical surface ruptures, liquefaction features, and shaking-induced ground deformation structures provides fundamental information on the past behavior of earthquake sources. These studies quantify (a) the timing of individual past earthquakes and fault slip rates, which lead to estimates of recurrence intervals and the development of recurrence models and (b) the amount of displacement during individual events, which allows estimates of the sizes of past earthquakes on a fault. When timing and slip per event are combined with information on fault zone geometry and structure, models that define individual rupture segments can be developed. Paleoseismicity data, in the form of timing and size of past events, provide a window into the driving mechanism of the earthquake engine--the cycle of stress build-up and release.

  6. Scaling of Seismic Memory with Earthquake Size

    CERN Document Server

    Zheng, Zeyu; Tenenbaum, Joel; Podobnik, Boris; Stanley, H Eugene


    It has been observed that the earthquake events possess short-term memory, i.e. that events occurring in a particular location are dependent on the short history of that location. We conduct an analysis to see whether real-time earthquake data also possess long-term memory and, if so, whether such autocorrelations depend on the size of earthquakes within close spatiotemporal proximity. We analyze the seismic waveform database recorded by 64 stations in Japan, including the 2011 "Great East Japan Earthquake", one of the five most powerful earthquakes ever recorded which resulted in a tsunami and devastating nuclear accidents. We explore the question of seismic memory through use of mean conditional intervals and detrended fluctuation analysis (DFA). We find that the waveform sign series show long-range power-law anticorrelations while the interval series show long-range power-law correlations. We find size-dependence in earthquake auto-correlations---as earthquake size increases, both of these correlation beha...

  7. Smartphone MEMS accelerometers and earthquake early warning (United States)

    Kong, Q.; Allen, R. M.; Schreier, L.; Kwon, Y. W.


    The low cost MEMS accelerometers in the smartphones are attracting more and more attentions from the science community due to the vast number and potential applications in various areas. We are using the accelerometers inside the smartphones to detect the earthquakes. We did shake table tests to show these accelerometers are also suitable to record large shakings caused by earthquakes. We developed an android app - MyShake, which can even distinguish earthquake movements from daily human activities from the recordings recorded by the accelerometers in personal smartphones and upload trigger information/waveform to our server for further analysis. The data from these smartphones forms a unique datasets for seismological applications, such as earthquake early warning. In this talk I will layout the method we used to recognize earthquake-like movement from single smartphone, and the overview of the whole system that harness the information from a network of smartphones for rapid earthquake detection. This type of system can be easily deployed and scaled up around the global and provides additional insights of the earthquake hazards.

  8. Ionospheric precursors for crustal earthquakes in Italy

    Directory of Open Access Journals (Sweden)

    L. Perrone


    Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  9. Stress triggering and the Canterbury earthquake sequence (United States)

    Steacy, Sandy; Jiménez, Abigail; Holden, Caroline


    The Canterbury earthquake sequence, which includes the devastating Christchurch event of 2011 February, has to date led to losses of around 40 billion NZ dollars. The location and severity of the earthquakes was a surprise to most inhabitants as the seismic hazard model was dominated by an expected Mw > 8 earthquake on the Alpine fault and an Mw 7.5 earthquake on the Porters Pass fault, 150 and 80 km to the west of Christchurch. The sequence to date has included an Mw = 7.1 earthquake and 3 Mw ≥ 5.9 events which migrated from west to east. Here we investigate whether the later events are consistent with stress triggering and whether a simple stress map produced shortly after the first earthquake would have accurately indicated the regions where the subsequent activity occurred. We find that 100 per cent of M > 5.5 earthquakes occurred in positive stress areas computed using a slip model for the first event that was available within 10 d of its occurrence. We further find that the stress changes at the starting points of major slip patches of post-Darfield main events are consistent with triggering although this is not always true at the hypocentral locations. Our results suggest that Coulomb stress changes contributed to the evolution of the Canterbury sequence and we note additional areas of increased stress in the Christchurch region and on the Porters Pass fault.

  10. The Road to Total Earthquake Safety (United States)

    Frohlich, Cliff

    Cinna Lomnitz is possibly the most distinguished earthquake seismologist in all of Central and South America. Among many other credentials, Lomnitz has personally experienced the shaking and devastation that accompanied no fewer than five major earthquakes—Chile, 1939; Kern County, California, 1952; Chile, 1960; Caracas,Venezuela, 1967; and Mexico City, 1985. Thus he clearly has much to teach someone like myself, who has never even actually felt a real earthquake.What is this slim book? The Road to Total Earthquake Safety summarizes Lomnitz's May 1999 presentation at the Seventh Mallet-Milne Lecture, sponsored by the Society for Earthquake and Civil Engineering Dynamics. His arguments are motivated by the damage that occurred in three earthquakes—Mexico City, 1985; Loma Prieta, California, 1989; and Kobe, Japan, 1995. All three quakes occurred in regions where earthquakes are common. Yet in all three some of the worst damage occurred in structures located a significant distance from the epicenter and engineered specifically to resist earthquakes. Some of the damage also indicated that the structures failed because they had experienced considerable rotational or twisting motion. Clearly, Lomnitz argues, there must be fundamental flaws in the usually accepted models explaining how earthquakes generate strong motions, and how we should design resistant structures.

  11. Mapping of earthquakes vulnerability area in Papua (United States)

    Muhammad Fawzy Ismullah, M.; Massinai, Muh. Altin


    Geohazard is a geological occurrence which may lead to a huge loss for human. A mitigation of these natural disasters is one important thing to be done properly in order to reduce the risks. One of the natural disasters that frequently occurs in the Papua Province is the earthquake. This study applies the principle of Geospatial and its application for mapping the earthquake-prone area in the Papua region. It uses earthquake data, which is recorded for 36 years (1973-2009), fault location map, and ground acceleration map of the area. The earthquakes and fault map are rearranged into an earthquake density map, as well as an earthquake depth density map and fault density map. The overlaid data of these three maps onto ground acceleration map are then (compiled) to obtain an earthquake unit map. Some districts area, such as Sarmi, Nabire, and Dogiyai, are identified by a high vulnerability index. In the other hand, Waropen, Puncak, Merauke, Asmat, Mappi, and Bouven Digoel area shows lower index. Finally, the vulnerability index in other places is detected as moderate.

  12. Earthquake rate and magnitude distributions of great earthquakes for use in global forecasts (United States)

    Kagan, Yan Y.; Jackson, David D.


    We have obtained new results in the statistical analysis of global earthquake catalogues with special attention to the largest earthquakes, and we examined the statistical behaviour of earthquake rate variations. These results can serve as an input for updating our recent earthquake forecast, known as the `Global Earthquake Activity Rate 1' model (GEAR1), which is based on past earthquakes and geodetic strain rates. The GEAR1 forecast is expressed as the rate density of all earthquakes above magnitude 5.8 within 70 km of sea level everywhere on earth at 0.1 × 0.1 degree resolution, and it is currently being tested by the Collaboratory for Study of Earthquake Predictability. The seismic component of the present model is based on a smoothed version of the Global Centroid Moment Tensor (GCMT) catalogue from 1977 through 2013. The tectonic component is based on the Global Strain Rate Map, a `General Earthquake Model' (GEM) product. The forecast was optimized to fit the GCMT data from 2005 through 2012, but it also fit well the earthquake locations from 1918 to 1976 reported in the International Seismological Centre-Global Earthquake Model (ISC-GEM) global catalogue of instrumental and pre-instrumental magnitude determinations. We have improved the recent forecast by optimizing the treatment of larger magnitudes and including a longer duration (1918-2011) ISC-GEM catalogue of large earthquakes to estimate smoothed seismicity. We revised our estimates of upper magnitude limits, described as corner magnitudes, based on the massive earthquakes since 2004 and the seismic moment conservation principle. The new corner magnitude estimates are somewhat larger than but consistent with our previous estimates. For major subduction zones we find the best estimates of corner magnitude to be in the range 8.9 to 9.6 and consistent with a uniform average of 9.35. Statistical estimates tend to grow with time as larger earthquakes occur. However, by using the moment conservation

  13. Typical Scenario of Preparation, Implementation, and Aftershock Sequence of a Large Earthquake (United States)

    Rodkin, Mikhail


    We have tried here to construct and examine the typical scenario of a large earthquake occurrence. The Harvard seismic moment GCMT catalog was used to construct the large earthquake generalized space-time vicinity (LEGV) and to investigate the seismicity behavior in LEGV. LEGV was composed of earthquakes falling into the zone of influence of any of the considerable number (100, 300, or 1,000) of largest earthquakes. The LEGV construction is aimed to enlarge the available statistics, diminish a strong random component, and to reveal in result the typical features of pre- and post-shock seismic activity in more detail. In result of the LEGV construction the character of fore- and aftershock cascades was examined in more detail than it was possible without of the use of the LEGV approach. It was shown also that the mean earthquake magnitude tends to increase, and the b-values, mean mb/mw ratios, apparent stress values, and mean depth tend to decrease. Amplitudes of all these anomalies increase with an approach to a moment of the generalized large earthquake (GLE) as a logarithm of time interval from GLE occurrence. Most of the discussed anomalies agree well with a common scenario of development of instability. Besides of such precursors of common character, one earthquake-specific precursor was found. The revealed decrease of mean earthquake depth during large earthquake preparation testifies probably for the deep fluid involvement in the process. The revealed in LEGV typical features of development of shear instability agree well with results obtained in laboratory acoustic emission (AE) study. Majority of the revealed anomalies appear to have a secondary character and are connected mainly with an increase in a mean earthquake magnitude in LEGV. The mean magnitude increase was shown to be connected mainly with a decrease of a portion of moderate size events (Mw 5.0 - 5.5) in a closer GLE vicinity. We believe that this deficit of moderate size events hardly can be

  14. Earthquakes (United States)

    ... Part 3 of 3) Hot Weather Tips Heat Stress in Older Adults FAQs Extreme Heat PSAs Related Links MMWR Bibliography CDC's Program Floods Flood Readiness Personal Hygiene After a Disaster Cleanup of Flood Water After a Flood Worker Safety Educational Materials Floods ...

  15. Earthquakes (United States)

    ... Landslides & Debris Flow Nuclear Blast Nuclear Power Plants Power Outages Pandemic Radiological Dispersion Device Severe Weather Snowstorms & Extreme ... Landslides & Debris Flow Nuclear Blast Nuclear Power Plants Power Outages Pandemic Radiological Dispersion Device Severe Weather Snowstorms & Extreme ...

  16. POST Earthquake Debris Management - AN Overview (United States)

    Sarkar, Raju

    Every year natural disasters, such as fires, floods, earthquakes, hurricanes, landslides, tsunami, and tornadoes, challenge various communities of the world. Earthquakes strike with varying degrees of severity and pose both short- and long-term challenges to public service providers. Earthquakes generate shock waves and displace the ground along fault lines. These seismic forces can bring down buildings and bridges in a localized area and damage buildings and other structures in a far wider area. Secondary damage from fires, explosions, and localized flooding from broken water pipes can increase the amount of debris. Earthquake debris includes building materials, personal property, and sediment from landslides. The management of this debris, as well as the waste generated during the reconstruction works, can place significant challenges on the national and local capacities. Debris removal is a major component of every post earthquake recovery operation. Much of the debris generated from earthquake is not hazardous. Soil, building material, and green waste, such as trees and shrubs, make up most of the volume of earthquake debris. These wastes not only create significant health problems and a very unpleasant living environment if not disposed of safely and appropriately, but also can subsequently impose economical burdens on the reconstruction phase. In practice, most of the debris may be either disposed of at landfill sites, reused as materials for construction or recycled into useful commodities Therefore, the debris clearance operation should focus on the geotechnical engineering approach as an important post earthquake issue to control the quality of the incoming flow of potential soil materials. In this paper, the importance of an emergency management perspective in this geotechnical approach that takes into account the different criteria related to the operation execution is proposed by highlighting the key issues concerning the handling of the construction

  17. Sense of Community and Depressive Symptoms among Older Earthquake Survivors Following the 2008 Earthquake in Chengdu China (United States)

    Li, Yawen; Sun, Fei; He, Xusong; Chan, Kin Sun


    This study examined the impact of an earthquake as well as the role of sense of community as a protective factor against depressive symptoms among older Chinese adults who survived an 8.0 magnitude earthquake in 2008. A household survey of a random sample was conducted 3 months after the earthquake and 298 older earthquake survivors participated…

  18. Ionospheric Signatures of the Earthquake in South Korea on 31 March 2014 (United States)

    Choi, P. H.; Yoon, M.; Yang, Y. M.; Lee, J.; Komjathy, A.


    Previous studies on interactions between the atmospheric waves and ionospheric perturbations concluded that the acoustic-gravity waves triggered by solid earth events such as earthquakes, tsunamis and underground nuclear tests may be used in detecting the ionospheric perturbations. Ionospheric perturbations have been observed using sounding radars and GPS remote sensing techniques since 1970s. As primary examples, ionospheric disturbances associated with the Tohoku earthquake and tsunami on March 11, 2011 were observed and analyzed using GPS measurements. In this work, we processed GPS stations in South Korea and analyzed traveling ionospheric disturbances that were coincident with the 2014 South Korean earthquake. The 31 March 2014 earthquake occurred at 19:48 UTC and the magnitude of this event was registered to be 5.0 Mw. This earthquake is the fourth strongest in South Korea since records began. After analyzing GPS measurements from nearby stations, strong ionospheric perturbations were observed about 20 minutes after the reported event, and the disturbances were shown to have primarily a wave train with periods of 60-120 minutes. The maximum VTEC perturbations turned out to be between 0.6 to 1.3 TECU. In this research, we will analyze the characteristics of the detected ionospheric perturbations associated with the earthquake and compare these results with those from man-made earthquakes such as underground nuclear tests. These findings are expected to verify our modeling results. We also hope to get a better understanding of the influence of both natural hazards and man-made hazards on the temporal and spatial variability of the global ionosphere

  19. A 'new generation' earthquake catalogue

    Directory of Open Access Journals (Sweden)

    E. Boschi


    Full Text Available In 1995, we published the first release of the Catalogo dei Forti Terremoti in Italia, 461 a.C. - 1980, in Italian (Boschi et al., 1995. Two years later this was followed by a second release, again in Italian, that included more earthquakes, more accurate research and a longer time span (461 B.C. to 1990 (Boschi et al., 1997. Aware that the record of Italian historical seismicity is probably the most extensive of the whole world, and hence that our catalogue could be of interest for a wider interna-tional readership, Italian was clearly not the appropriate language to share this experience with colleagues from foreign countries. Three years after publication of the second release therefore, and after much additional research and fine tuning of methodologies and algorithms, I am proud to introduce this third release in English. All the tools and accessories have been translated along with the texts describing the development of the underlying research strategies and current contents. The English title is Catalogue of Strong Italian Earthquakes, 461 B.C. to 1997. This Preface briefly describes the scientific context within which the Catalogue of Strong Italian Earthquakes was conceived and progressively developed. The catalogue is perhaps the most impor-tant outcome of a well-established joint project between the Istituto Nazionale di Geofisica, the leading Italian institute for basic and applied research in seismology and solid earth geophysics, and SGA (Storia Geofisica Ambiente, a private firm specialising in the historical investigation and systematisation of natural phenomena. In her contribution "Method of investigation, typology and taxonomy of the basic data: navigating between seismic effects and historical contexts", Emanuela Guidoboni outlines the general framework of modern historical seismology, its complex relation with instrumental seismology on the one hand and historical research on the other. This presentation also highlights

  20. The Focal Property of the 2014 Ms6.3 Kangding, China Earthquake and its Resulting Stress Changes on Surrounding Faults (United States)

    Xie, Z.


    An Ms6.3 earthquake struck Kangding County, Garze Tibetan Autonomous Prefecture in Sichuan province on November 22, 2014 and is one of the destructive earthquakes on the eastern boundary of Chuandian rhomb faulted-block in southwestern China, where is one of the areas with strong seismic activity in continent. During the earthquake, at least 5 people killed, 65 injured, lots of homes were collapsed and thousands people displaced. Ending the history that no large earthquake occurs at Xianshuihe fault zone for nearly 30 years, this moderate earthquake arouses the highly attention of many seismologists, not only for the serious disaster, but also for the potential seismic risk in and surrounding the epicenter. In order to better understand the seismogenic structure and the seismic risk of the source region, we collect teleseismic waveforms from IRIS and broadband seismograms from seismograph network in Yunnan and its surrounding provinces, and apply CAP method to grid search the focal mechanism and centroid depth of the earthquake. And the rupture process of this event is investigated based on finite fault inversion method. After that, we calculate stress influences on Kangding earthquake from the Wenchuan and Lushan earthquake, and study the stress changes on Xianshuihe Fault caused by the Kanding earthquake to assess the future seismic hazard. The result shows that the epicenter of Kangding earthquake is 101.689°E and 30.262°N, with a focal depth of 9 km and magnitude of about Mw6.0. The two nodal planes of focal mechanism are 235°/82°/-173° and 144°/83°/-8°. Considering the tectonic background, the latter nodal plane is adopted as the parameters of receiver fault while calculating the stress changes on the hypocenter of Kangding earthquake. the major slip is located around the hypocenter, spanning ~8 km along dip and ~10 km along strike with a maximum slip of 0.5 m. The stress accumulation on the Kangding-Daofu segment, surrounding to the epicenter of the

  1. Possible occurrence of a giant interplate earthquake in northeast Japan greater than the 2011 Tohoku earthquake (United States)

    Ohtani, M.; Hirahara, K.; Hori, T.; Hyodo, M.


    We supposed there occur M7-class earthquakes and the co-rupturing M8 earthquakes on the Pacific plate interface subducting beneath northeast Japan. Against our speculation, the 2011 Tohoku earthquake grew up to Mw9.0. We have so far constructed cycle models of this giant earthquake to understand why this grew up to Mw9.0. Next question is; is there any possibility that a much larger earthquake occurs in this region? In this study, we explore this possibility through quasi-dynamic earthquake cycle simulations. The 2011 Tohoku earthquake ruptured a large region of 200km x 500km. The rupture region includes a confined area with huge coseismic slip over 50 m in the shallow Off-Miyagi region close to the Japan Trench, and several M7 asperities in Off-Miyagi and Ibaraki regions which have been ruptured repeatedly at intervals of several ten years. The tsunami deposit surveys suggest this giant earthquake has the recurrence time of several hundred years. The afterslip occurs mainly in the deeper region of the coseismic slip region, except the Off-Miyagi region [Ozawa et al., 2012]. At Off-Kamaishi and Off-Fukushima regions located in the northern and southern sides of the Off-Miyagi region, we can find the local maximum of the afterslip. The Off-Kamaishi region did not produce much coseismic slip, and has not experienced historical large earthquakes. And no large afterslip extended to the northern region beyond Off-Kamaishi. Then, the Off-Kamaishi region is a kind of boundary between the 2011 Tohoku earthquake and its adjacent northern regions. In the northern region, there occurred the 1968 Off-Tokachi Mw8.3 earthquake, which has three M7 asperities with recurrence times of several ten years [Yamanaka & Kikuchi, 2004]. An aftershock of the 2011 Tohoku earthquake, which occurred 22 minutes after the main shock, is located at the southern asperity area. And there is a region close to the Japan Trench, where the 1897 Meiji-sanriku tsunami earthquake occurred. We performed

  2. Time-history simulation of civil architecture earthquake disaster relief- based on the three-dimensional dynamic finite element method

    Directory of Open Access Journals (Sweden)

    Liu Bing


    Full Text Available Earthquake action is the main external factor which influences long-term safe operation of civil construction, especially of the high-rise building. Applying time-history method to simulate earthquake response process of civil construction foundation surrounding rock is an effective method for the anti-knock study of civil buildings. Therefore, this paper develops a civil building earthquake disaster three-dimensional dynamic finite element numerical simulation system. The system adopts the explicit central difference method. Strengthening characteristics of materials under high strain rate and damage characteristics of surrounding rock under the action of cyclic loading are considered. Then, dynamic constitutive model of rock mass suitable for civil building aseismic analysis is put forward. At the same time, through the earthquake disaster of time-history simulation of Shenzhen Children’s Palace, reliability and practicability of system program is verified in the analysis of practical engineering problems.

  3. Revisit the classical Newmark displacement method for earthquake-induced wedge slide (United States)

    Yang, Che-Ming; Cheng, Hui-Yun; Wu, Wen-Jie; Hsu, Chang-Hsuan; Dong, Jia-Jyun; Lee, Chyi-Tyi


    Newmark displacement method has been widely used to study the earthquake-induced landslides and adopted to explore the initiation and kinematics of catastrophic planar failure in recent years. However, surprisingly few researchers utilize the Newmark displacement method to study the earthquake-induced wedge slide. The classical Newmark displacement method for earthquake-induced wedge sliding assumed the wedge is rigid and the vertical acceleration, as well as the horizontal acceleration perpendicular to the sliding direction, is neglected. Moreover, the friction coefficients on the weak planes are assumed as unchanged during sliding. The purpose of this study is to test the reasonableness of the aforementioned assumptions. This study uses Newmark displacement method incorporating the rigid wedge method (RWM) and maximum shear stress method (MSSM) to evaluate the influence of wedge deformation. We design the geometry of the wedge and input the synthetic seismicity to trigger the wedge slide. The influence for neglecting the vertical and horizontal (perpendicular to the sliding direction) accelerations is also assessed. Besides, this research incorporates the velocity-displacement dependent friction law in the analysis to evaluate the influence of constant friction coefficient assumption. Result of this study illustrated that the aforementioned assumptions have significant effects on the calculated permeant displacement, moving speed, and failure initiation. To conclude, this study provides new insights on the initiation and kinematics of an earthquake induced wedge slide.

  4. Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part A, Prehistoric earthquakes (United States)

    Wheeler, Russell L.


    Computation of probabilistic earthquake hazard requires an estimate of Mmax, the maximum earthquake magnitude thought to be possible within a specified geographic region. This report is Part A of an Open-File Report that describes the construction of a global catalog of moderate to large earthquakes, from which one can estimate Mmax for most of the Central and Eastern United States and adjacent Canada. The catalog and Mmax estimates derived from it were used in the 2014 edition of the U.S. Geological Survey national seismic-hazard maps. This Part A discusses prehistoric earthquakes that occurred in eastern North America, northwestern Europe, and Australia, whereas a separate Part B deals with historical events.

  5. Earthquake Risk - EARTHQUAKE_LIQUEFACTION_IN: Earthquake Paleoliquefaction Sites in Indiana (Indiana Geological Survey, 1:24,000, Point Shapefile) (United States)

    NSGIC GIS Inventory (aka Ramona) — EARTHQUAKE_LIQUEFACTION_IN is a point shapefile that shows sites where paleoliquefaction features have been identified in the field by Pat Munson of the Indiana...

  6. Earthquake Scenarios and Comparison with Historical Earthquakes, Hatay Region, SE Turkey (United States)

    Uskuplu, S.; Tuysuz, O.


    Hatay Province (Antioch on Orontes) and its surroundings, SE Turkey, have been studied in this research. Tectonically, the East Anatolian Fault Zone (EAFZ), Dead Sea Fault Zone (DAFZ) and Cyprus Arc juxtapose in this region and form a triple junction. Historical records, which extend back to 300 BC, indicate that repeated destructive earthquakes affected this historical region for many times. It is still a matter of debate in this region that which fault produced these earthquakes. It is indisputable for this region that the probability of occurrence of future big and destructive earthquakes are quite high. For that purpose, the damage distributions of the historical earthquakes of this region, which are compiled from various catalogues, have been investigated in this study. The active faults in the region are determined by field studies and the maximum magnitudes of the earthquakes that can be produced by those faults are calculated by using empirical formulas. In the next step we produced synthetic earthquake scenarios by using Geographical Information System (GIS) analysis techniques to estimate the damage distribution of earthquakes that would possibly be produced by different fault segments. In the last step we compared results of damage distribution of synthetic earthquake scenarios with the damage distribution from historical records. Based on these results we tried to estimate which fault segment produced which historical earthquake. Results of our study indicate that the historical earthquakes in the Hatay Province were mainly produced by different segments of the Dead Sea Fault, and the Antakya-Samandag Fault. Keywords; Earthquake scenarios, GIS, historical earthquakes, Hatay, intensity

  7. Strong Ground Motion in the 2011 Tohoku Earthquake: a 1Directional - 3Component Modeling

    CERN Document Server

    D'Avila, Maria Paola Santisi; Lenti, Luca


    Local wave amplification due to strong seismic motions in surficial multilayered soil is influenced by several parameters such as the wavefield polarization and the dynamic properties and impedance contrast between soil layers. The present research aims at investigating seismic motion amplification in the 2011 Tohoku earthquake through a one-directional three-component (1D-3C) wave propagation model. A 3D nonlinear constitutive relation for dry soils under cyclic loading is implemented in a quadratic line finite element model. The soil rheology is modeled by mean of a multi-surface cyclic plasticity model of the Masing-Prandtl-Ishlinskii-Iwan (MPII) type. Its major advantage is that the rheology is characterized by few commonly measured parameters. Ground motions are computed at the surface of soil profiles in the Tohoku area (Japan) by propagating 3C signals recorded at rock outcrops, during the 2011 Tohoku earthquake. Computed surface ground motions are compared to the Tohoku earthquake records at alluvial ...

  8. Space Geodetic Observations and Modeling of 2016 Mw 5.9 Menyuan Earthquake: Implications on Seismogenic Tectonic Motion

    Directory of Open Access Journals (Sweden)

    Yongsheng Li


    Full Text Available Determining the relationship between crustal movement and faulting in thrust belts is essential for understanding the growth of geological structures and addressing the proposed models of a potential earthquake hazard. A Mw 5.9 earthquake occurred on 21 January 2016 in Menyuan, NE Qinghai Tibetan plateau. We combined satellite interferometry from Sentinel-1A Terrain Observation with Progressive Scans (TOPS images, historical earthquake records, aftershock relocations and geological data to determine fault seismogenic structural geometry and its relationship with the Lenglongling faults. The results indicate that the reverse slip of the 2016 earthquake is distributed on a southwest dipping shovel-shaped fault segment. The main shock rupture was initiated at the deeper part of the fault plane. The focal mechanism of the 2016 earthquake is quite different from that of a previous Ms 6.5 earthquake which occurred in 1986. Both earthquakes occurred at the two ends of a secondary fault. Joint analysis of the 1986 and 2016 earthquakes and aftershocks distribution of the 2016 event reveals an intense connection with the tectonic deformation of the Lenglongling faults. Both earthquakes resulted from the left-lateral strike-slip of the Lenglongling fault zone and showed distinct focal mechanism characteristics. Under the shearing influence, the normal component is formed at the releasing bend of the western end of the secondary fault for the left-order alignment of the fault zone, while the thrust component is formed at the restraining bend of the east end for the right-order alignment of the fault zone. Seismic activity of this region suggests that the left-lateral strike-slip of the Lenglongling fault zone plays a significant role in adjustment of the tectonic deformation in the NE Tibetan plateau.

  9. Earthquake prediction with electromagnetic phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Masashi, E-mail: [Hayakawa Institute of Seismo Electomagnetics, Co. Ltd., University of Electro-Communications (UEC) Incubation Center, 1-5-1 Chofugaoka, Chofu Tokyo, 182-8585 (Japan); Advanced Wireless & Communications Research Center, UEC, Chofu Tokyo (Japan); Earthquake Analysis Laboratory, Information Systems Inc., 4-8-15, Minami-aoyama, Minato-ku, Tokyo, 107-0062 (Japan); Fuji Security Systems. Co. Ltd., Iwato-cho 1, Shinjyuku-ku, Tokyo (Japan)


    Short-term earthquake (EQ) prediction is defined as prospective prediction with the time scale of about one week, which is considered to be one of the most important and urgent topics for the human beings. If this short-term prediction is realized, casualty will be drastically reduced. Unlike the conventional seismic measurement, we proposed the use of electromagnetic phenomena as precursors to EQs in the prediction, and an extensive amount of progress has been achieved in the field of seismo-electromagnetics during the last two decades. This paper deals with the review on this short-term EQ prediction, including the impossibility myth of EQs prediction by seismometers, the reason why we are interested in electromagnetics, the history of seismo-electromagnetics, the ionospheric perturbation as the most promising candidate of EQ prediction, then the future of EQ predictology from two standpoints of a practical science and a pure science, and finally a brief summary.

  10. The ethics of earthquake prediction. (United States)

    Sol, Ayhan; Turan, Halil


    Scientists' responsibility to inform the public about their results may conflict with their responsibility not to cause social disturbance by the communication of these results. A study of the well-known Brady-Spence and Iben Browning earthquake predictions illustrates this conflict in the publication of scientifically unwarranted predictions. Furthermore, a public policy that considers public sensitivity caused by such publications as an opportunity to promote public awareness is ethically problematic from (i) a refined consequentialist point of view that any means cannot be justified by any ends, and (ii) a rights view according to which individuals should never be treated as a mere means to ends. The Parkfield experiment, the so-called paradigm case of cooperation between natural and social scientists and the political authorities in hazard management and risk communication, is also open to similar ethical criticism. For the people in the Parkfield area were not informed that the whole experiment was based on a contested seismological paradigm.

  11. Perception of earthquake risk in Taiwan: effects of gender and past earthquake experience. (United States)

    Kung, Yi-Wen; Chen, Sue-Huei


    This study explored how individuals in Taiwan perceive the risk of earthquake and the relationship of past earthquake experience and gender to risk perception. Participants (n= 1,405), including earthquake survivors and those in the general population without prior direct earthquake exposure, were selected and interviewed through a computer-assisted telephone interviewing procedure using a random sampling and stratification method covering all 24 regions of Taiwan. A factor analysis of the interview data yielded a two-factor structure of risk perception in regard to earthquake. The first factor, "personal impact," encompassed perception of threat and fear related to earthquakes. The second factor, "controllability," encompassed a sense of efficacy of self-protection in regard to earthquakes. The findings indicated prior earthquake survivors and females reported higher scores on the personal impact factor than males and those with no prior direct earthquake experience, although there were no group differences on the controllability factor. The findings support that risk perception has multiple components, and suggest that past experience (survivor status) and gender (female) affect the perception of risk. Exploration of potential contributions of other demographic factors such as age, education, and marital status to personal impact, especially for females and survivors, is discussed. Future research on and intervention program with regard to risk perception are suggested accordingly.

  12. Earthquake Damage Assessment Using Objective Image Segmentation: A Case Study of 2010 Haiti Earthquake (United States)

    Oommen, Thomas; Rebbapragada, Umaa; Cerminaro, Daniel


    In this study, we perform a case study on imagery from the Haiti earthquake that evaluates a novel object-based approach for characterizing earthquake induced surface effects of liquefaction against a traditional pixel based change technique. Our technique, which combines object-oriented change detection with discriminant/categorical functions, shows the power of distinguishing earthquake-induced surface effects from changes in buildings using the object properties concavity, convexity, orthogonality and rectangularity. Our results suggest that object-based analysis holds promise in automatically extracting earthquake-induced damages from high-resolution aerial/satellite imagery.

  13. Effects of acoustic waves on stick-slip in granular media and implications for earthquakes (United States)

    Johnson, P.A.; Savage, H.; Knuth, M.; Gomberg, J.; Marone, C.


    It remains unknown how the small strains induced by seismic waves can trigger earthquakes at large distances, in some cases thousands of kilometres from the triggering earthquake, with failure often occurring long after the waves have passed. Earthquake nucleation is usually observed to take place at depths of 10-20 km, and so static overburden should be large enough to inhibit triggering by seismic-wave stress perturbations. To understand the physics of dynamic triggering better, as well as the influence of dynamic stressing on earthquake recurrence, we have conducted laboratory studies of stick-slip in granular media with and without applied acoustic vibration. Glass beads were used to simulate granular fault zone material, sheared under constant normal stress, and subject to transient or continuous perturbation by acoustic waves. Here we show that small-magnitude failure events, corresponding to triggered aftershocks, occur when applied sound-wave amplitudes exceed several microstrain. These events are frequently delayed or occur as part of a cascade of small events. Vibrations also cause large slip events to be disrupted in time relative to those without wave perturbation. The effects are observed for many large-event cycles after vibrations cease, indicating a strain memory in the granular material. Dynamic stressing of tectonic faults may play a similar role in determining the complexity of earthquake recurrence. ??2007 Nature Publishing Group.

  14. Semen quality in adult male survivors 5 years after the 2008 Wenchuan earthquake. (United States)

    Chen, X M; Chen, S M; Yue, H X; Lin, L; Wu, Y B; Liu, B; Jiang, M; Ma, Y X


    The influence of the Wenchuan earthquake on semen quality of adult male survivors is unclear. We investigated the semen quality included 673 male survivors from the worse-affected counties in the earthquake between Aug 2008 and July 2013. Semen parameters including pH, volume, concentration, motility and morphology were measured according to the World Health Organization (WHO) criteria. Kruskal-Wallis analysis of variance was used to examine the statistical differences between years, and a logistic regression was used to analyse the impacts caused by earthquake on the changes of semen quality. We found the medians (5th and 95th) were 2.5 ml (0.6-5.5) for semen volume, 59.0 × 10(6)  ml(-1) [(13.0-133.0)] × 10(6)  ml(-1) for semen concentration, 46% (13-64%) for sperm progressive motility and 3.0% (0-17.5%) for normal morphology for adult male survivors. Semen concentration, the percentage of sperm progressive motility, total motility and sperm normal morphology were all decreased in the first 3 years, and the differences among years 1, 2 and 3 were significant except the percentage of sperm progressive motility (P earthquake had a negative effect on semen quality. The main findings will provide further diagnosis and therapy basis of male fertility by data, for affected populations in the earthquake.

  15. Maternal PTSD following Exposure to the Wenchuan Earthquake Is Associated with Impaired Mental Development of Children (United States)

    Cai, Dongge; Zhu, Zhongliang; Sun, Hongli; Qi, Yanhua; Xing, Lanying; Zhao, Xiaogui; Wan, Qiuyuan; Su, Qian; Li, Hui


    The purpose of this study was to explore whether earthquake-related maternal Post-Traumatic Stress Disorder (PTSD) is associated with impaired development of infants. Participants included 86 women who were pregnant during or after the earthquake in Ningqiang county, and their children. Data were collected from February to March of 2012. PTSD questionnaire (PTSD Checklist, Civilian Version (PCL-C)) was used to measure the effect of the earthquake on mothers, and that the scores greater than 50 were used to indicate presence of PTSD. Each child was assessed using the mental Developmental Screening Test (DST) according to age. Among the 86 women, PTSD scores equal to or greater than 50 accounted for 20.93%. Among the 86 children, 25.60% of development quotient (DQ) scores and 19.80% of mental index (MI) scores were less than 85. The correlation coefficient analysis showed that PTSD scores were inversely related to DQ and MI scores. Maternal PTSD following earthquake exposure is associated with relatively lower intellectual development in children age 0–3 years. Further research is needed to assess the persistent effects of this influence on offspring of mothers exposed to earthquake. PMID:28369095

  16. Application of fuzzy theory on earthquake damage rate estimation of buildings

    Institute of Scientific and Technical Information of China (English)

    邵扬威; 吴玉祥; 高士峰; 黄麒然; 张宽勇


    Variations between earthquakes result in many factors that influence post-earthquake building damage (e.g., ground motion parameters, building structure, site information, and quality of construction). Consequently, it is necessary to develop an appropriate building damage-rate estimation model. The building damage survey data were recorded and constructed into files by the Architecture and Building Research Institute (ABRI), Taiwan for the 1999 Chi-Chi earthquake in the Nantou region as a basis for developing a building damage rate estimation model by applying fuzzy theory to express the fragility curves of buildings as a membership function. Empirical verification was performed using post-earthquake building damage data in the Taichung city that suffered relatively severe damage. Results indicate that fuzzy theory can be applied to predict building damage rates and that the estimated results are similar to actual disaster figures. Prediction of disaster damage using building damage rates can provide a reference for immediate disaster response during earthquakes and for regular disaster prevention and rescue planning.

  17. Magnetic storm free ULF analysis in relation with earthquakes in Taiwan

    Directory of Open Access Journals (Sweden)

    S. Wen


    Full Text Available Despite early optimism, pre-earthquake anomalous phenomena can be determined by using enhanced amplitude at the ultra-low-frequency range from geomagnetic data via the Fourier transform. In reality, accuracy of the enhanced amplitude in relation to earthquakes (deduced from time-varied geomagnetic data would be damaged by magnetic storms and/or other unwanted influences resulting from solar activity and/or variations in the ionosphere, respectively. We substitute values of the cross correlation between amplitudes, summarized from the earthquake-related (0.1–0.01 Hz and the comparable (0.01–0.001 Hz frequency bands, for isolated amplitude enhancements as indexes of determination associated with seismo-magnetic anomalies to mitigate disturbance caused by magnetic storms. A station located about 300 km away from the others is also taken into account to further examine whether changes of the cross correlation values are caused by seismo-magnetic anomalies limited within local regions or not. Analytical results show that the values suddenly decrease near epicenters a few days before and after 67% (= 6/9 of earthquakes (M > = 5 in Taiwan between September 2010 and March 2011. Seismo-magnetic signals determined by using the values of cross correlation methods partially improve results yielded from the Fourier transform alone and provide advantageous information of earthquake locations.

  18. Analysis of Taipei Basin Response for Earthquakes of Various Depths and Locations Using Empirical Data

    Directory of Open Access Journals (Sweden)

    Vladimir Sokolov


    Full Text Available The response of Taipei basin upon earthquake excitation was studied using records of recent earthquakes. The strong-motion database includes records obtained at 32 stations of the Taipei TSMIP net work from 83 deep and 142 shallow earthquakes (M > 4.0 that occurred in 1992 - 2004. The characteristics of frequency-de pendent site response were obtained as spectral ratios between the actual earthquake records (horizontal components and those modelled for a hypothetical Very Hard Rock (VHR condition. The models for VHR spectra of Taiwan earthquakes had been recently proposed by Sokolov et al. (2005b, 2006. Analysis of site response characteristics and comparison with simple 1D models of the soil column resulted in the following conclusions: (1 The spectral ratios through out the basin obtained from deep earth quakes (depth > 35 km exhibit good agreement with the theoretical ratios calculated using the 1D models constructed using avail able geological and geotechnical data. (2 The spectral ratios obtained from shallow earth quakes show influence of: (a surface waves generated when travelling from distant sources to the basin and (b relatively low-frequency (< 1 - 2 Hz waves generated within the basin. (3 Some shallow earth quakes pro duce extremely high amplification at frequencies 0.3 - 1 Hz within the basin that may be dangerous for high-rise buildings and high way bridges. (4 The obtained results may be used in probabilistic seismic microzonation of the basin when many possible earth quakes located at various distances are considered. 2D and 3D simulation is necessary to model the seismic influence from particularly large earthquakes.

  19. Earthquake Damage, Northern Iran, June 21, 1990 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A magnitude 7.7 earthquake occurred in the Gilan Province between the towns of Rudbar and Manjil in northern Iran on Thursday, June 21, 1990. The event, the largest...


    Directory of Open Access Journals (Sweden)

    V.V. Kuznetsov


    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud

  1. Disturbances in equilibrium function after major earthquake (United States)

    Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi


    Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.

  2. Strong ground motion prediction using virtual earthquakes. (United States)

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C


    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  3. Is It Possible to Predict Strong Earthquakes?

    CERN Document Server

    Polyakov, Yuriy S; Solovyeva, Anna B; Timashev, Serge F


    The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on February 28, 2013), recorded at two different sites in the south-eastern part of the Kamchatka peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geoph...

  4. The 15 April 1909 Taipei Earthquake

    Directory of Open Access Journals (Sweden)

    Jeen-Hwa Wang


    Full Text Available In the very early morning at 03 h 53.7 m on 15 April 1909 (local time, a large earthquake occurred in northern Taiwan. In all, 9 persons were killed and 51 injured; 122 houses collapsed along with damage to another 1050 houses. This earthquake was one of the largest and most damaging events of the 20th century for the Taipei Metropolitan Area. The epicenter estimated by Hsu (1971 was determined to be 25¢XN, 121.53¢XE and its focal depth and earthquake magnitude evaluated by Gutenberg and Richter (1954 were ~80 km and MGR = 7.3, respectively. The event took place underneath the Taipei Metropolitan Area and might be located at the western edge of the subduction zone of the Philippine Sea plate. In this study, the magnitudes of the earthquakes determined by others will also be described.

  5. The aftershock signature of supershear earthquakes. (United States)

    Bouchon, Michel; Karabulut, Hayrullah


    Recent studies show that earthquake faults may rupture at speeds exceeding the shear wave velocity of rocks. This supershear rupture produces in the ground a seismic shock wave similar to the sonic boom produced by a supersonic airplane. This shock wave may increase the destruction caused by the earthquake. We report that supershear earthquakes are characterized by a specific pattern of aftershocks: The fault plane itself is remarkably quiet whereas aftershocks cluster off the fault, on secondary structures that are activated by the supershear rupture. The post-earthquake quiescence of the fault shows that friction is relatively uniform over supershear segments, whereas the activation of off-fault structures is explained by the shock wave radiation, which produces high stresses over a wide zone surrounding the fault.

  6. International Technical Communication after a Large Earthquake. (United States)

    Klein, Fred


    Discusses, in the context of southern California's severe earthquake in January 1994, attitudes to technology and the information superhighway. Argues that technology should not be worshipped as a solution. (SR)

  7. El Quindio Colombia Earthquake, January 25, 1999 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The El Quindio earthquake was one of the most destructive natural disasters to have occurred in Colombia in recent years. Long lasting economic and social impacts...

  8. NGA Nepal Earthquake Support Data Services (United States)

    National Geospatial Intelligence Agency — In support of the Spring 2015 Nepal earthquake response, NGA is providing to the public and humanitarian disaster response community these Nepal data services. They...

  9. Coping with earthquakes induced by fluid injection (United States)

    McGarr, Arthur F.; Bekins, Barbara; Burkardt, Nina; Dewey, James W.; Earle, Paul S.; Ellsworth, William L.; Ge, Shemin; Hickman, Stephen H.; Holland, Austin F.; Majer, Ernest; Rubinstein, Justin L.; Sheehan, Anne


    Large areas of the United States long considered geologically stable with little or no detected seismicity have recently become seismically active. The increase in earthquake activity began in the mid-continent starting in 2001 (1) and has continued to rise. In 2014, the rate of occurrence of earthquakes with magnitudes (M) of 3 and greater in Oklahoma exceeded that in California (see the figure). This elevated activity includes larger earthquakes, several with M > 5, that have caused significant damage (2, 3). To a large extent, the increasing rate of earthquakes in the mid-continent is due to fluid-injection activities used in modern energy production (1, 4, 5). We explore potential avenues for mitigating effects of induced seismicity. Although the United States is our focus here, Canada, China, the UK, and others confront similar problems associated with oil and gas production, whereas quakes induced by geothermal activities affect Switzerland, Germany, and others.

  10. Exploring Earthquakes in Real-Time (United States)

    Bravo, T. K.; Kafka, A. L.; Coleman, B.; Taber, J. J.


    Earthquakes capture the attention of students and inspire them to explore the Earth. Adding the ability to view and explore recordings of significant and newsworthy earthquakes in real-time makes the subject even more compelling. To address this opportunity, the Incorporated Research Institutions for Seismology (IRIS), in collaboration with Moravian College, developed ';jAmaSeis', a cross-platform application that enables students to access real-time earthquake waveform data. Students can watch as the seismic waves are recorded on their computer, and can be among the first to analyze the data from an earthquake. jAmaSeis facilitates student centered investigations of seismological concepts using either a low-cost educational seismograph or streamed data from other educational seismographs or from any seismic station that sends data to the IRIS Data Management System. After an earthquake, students can analyze the seismograms to determine characteristics of earthquakes such as time of occurrence, distance from the epicenter to the station, magnitude, and location. The software has been designed to provide graphical clues to guide students in the analysis and assist in their interpretations. Since jAmaSeis can simultaneously record up to three stations from anywhere on the planet, there are numerous opportunities for student driven investigations. For example, students can explore differences in the seismograms from different distances from an earthquake and compare waveforms from different azimuthal directions. Students can simultaneously monitor seismicity at a tectonic plate boundary and in the middle of the plate regardless of their school location. This can help students discover for themselves the ideas underlying seismic wave propagation, regional earthquake hazards, magnitude-frequency relationships, and the details of plate tectonics. The real-time nature of the data keeps the investigations dynamic, and offers students countless opportunities to explore.

  11. Mexican Earthquakes and Tsunamis Catalog Reviewed (United States)

    Ramirez-Herrera, M. T.; Castillo-Aja, R.


    Today the availability of information on the internet makes online catalogs very easy to access by both scholars and the public in general. The catalog in the "Significant Earthquake Database", managed by the National Center for Environmental Information (NCEI formerly NCDC), NOAA, allows access by deploying tabular and cartographic data related to earthquakes and tsunamis contained in the database. The NCEI catalog is the product of compiling previously existing catalogs, historical sources, newspapers, and scientific articles. Because NCEI catalog has a global coverage the information is not homogeneous. Existence of historical information depends on the presence of people in places where the disaster occurred, and that the permanence of the description is preserved in documents and oral tradition. In the case of instrumental data, their availability depends on the distribution and quality of seismic stations. Therefore, the availability of information for the first half of 20th century can be improved by careful analysis of the available information and by searching and resolving inconsistencies. This study shows the advances we made in upgrading and refining data for the earthquake and tsunami catalog of Mexico since 1500 CE until today, presented in the format of table and map. Data analysis allowed us to identify the following sources of error in the location of the epicenters in existing catalogs: • Incorrect coordinate entry • Place name erroneous or mistaken • Too general data that makes difficult to locate the epicenter, mainly for older earthquakes • Inconsistency of earthquakes and the tsunami occurrence: earthquake's epicenter located too far inland reported as tsunamigenic. The process of completing the catalogs directly depends on the availability of information; as new archives are opened for inspection, there are more opportunities to complete the history of large earthquakes and tsunamis in Mexico. Here, we also present new earthquake and

  12. Mechanical coupling between earthquakes, volcanos and landslides (United States)

    Feigl, K. L.; Retina Team


    "The eruption began as a large earthquake that triggered a massive landslide that culminated in a violent lateral explosion" [Malone et al., USGS 1981]. The 1980 eruption of Mount St. Helens taught a very powerful lesson -- that one natural hazard can trigger another. For example, earthquakes have triggered landslides in Papua New Guinea. Similarly, eruptions of Vesuvius are mechanically coupled to earthquakes in the Appenines, just as an inflating magma chamber can trigger earthquakes near Hengill volcano in SW Iceland and on the Izu Peninsula in Japan. The Luzon earthquake may have triggered the eruption of Mount Pinatubo. In many of these cases, the second triggered event caused more damage than the initial one. If we can better understand the mechanical coupling underlying the temporal and spatial correlation of such events, we will improve our assessments of the hazards they pose. The RETINA project has been funded by the European Commission's 5th Framework to study couplings between three classes of natural hazards: earthquakes, landslides, and volcanoes. These three phenomena are linked to and by the stress field in the crust. If the stress increases enough, the material will fail catastrophically. For example, magma injection beneath a volcano can trigger an earthquake by increasing stress on a fault. Increasing shear stress on unconsolidated materials on steep slopes can trigger landslides. Such stress change triggers may also be tectonic (from plate driving forces), hydrological (from heavy rain), or volcanic (magmatic injection). Any of these events can perturb the stress field enough to trigger another event. Indeed, stress changes as small as 0.1 bar (0.01 MPa) suffice to trigger an earthquake. If the medium is close to failure, this small change can increase the Coulomb stress beyond the yield threshold, breaking the material. This quantity is the primary means we will use for describing mechanical coupling. In this paper, we will review several case

  13. 10th World Earthquake Engineering Conference (United States)

    Ranguelov, Boyko; Housner, George

    The 10th World Conference on Earthquake Engineering (10WCEE) took place from July 19 to 24 in Madrid, Spain. More than 1500 participants from 51 countries attended the conference. All aspects of earthquake engineering were covered and a worldwide update of modern research and practice, as well as future directions in the field, was provided through reports, papers, posters, two keynote lectures, ten state-ofthe-art reports, and eleven special theme sessions.

  14. Evaluation of near-field earthquake effects

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, H.P.


    Structures and equipment, which are qualified for the design basis earthquake (DBE) and have anchorage designed for the DBE loading, do not require an evaluation of the near-field earthquake (NFE) effects. However, safety class 1 acceleration sensitive equipment such as electrical relays must be evaluated for both NFE and DBE since they are known to malfunction when excited by high frequency seismic motions.

  15. Earthquakes trigger the loss of groundwater biodiversity. (United States)

    Galassi, Diana M P; Lombardo, Paola; Fiasca, Barbara; Di Cioccio, Alessia; Di Lorenzo, Tiziana; Petitta, Marco; Di Carlo, Piero


    Earthquakes are among the most destructive natural events. The 6 April 2009, 6.3-Mw earthquake in L'Aquila (Italy) markedly altered the karstic Gran Sasso Aquifer (GSA) hydrogeology and geochemistry. The GSA groundwater invertebrate community is mainly comprised of small-bodied, colourless, blind microcrustaceans. We compared abiotic and biotic data from two pre-earthquake and one post-earthquake complete but non-contiguous hydrological years to investigate the effects of the 2009 earthquake on the dominant copepod component of the obligate groundwater fauna. Our results suggest that the massive earthquake-induced aquifer strain biotriggered a flushing of groundwater fauna, with a dramatic decrease in subterranean species abundance. Population turnover rates appeared to have crashed, no longer replenishing the long-standing communities from aquifer fractures, and the aquifer became almost totally deprived of animal life. Groundwater communities are notorious for their low resilience. Therefore, any major disturbance that negatively impacts survival or reproduction may lead to local extinction of species, most of them being the only survivors of phylogenetic lineages extinct at the Earth surface. Given the ecological key role played by the subterranean fauna as decomposers of organic matter and "ecosystem engineers", we urge more detailed, long-term studies on the effect of major disturbances to groundwater ecosystems.

  16. Earthquake detection through computationally efficient similarity search (United States)

    Yoon, Clara E.; O’Reilly, Ossian; Bergen, Karianne J.; Beroza, Gregory C.


    Seismology is experiencing rapid growth in the quantity of data, which has outpaced the development of processing algorithms. Earthquake detection—identification of seismic events in continuous data—is a fundamental operation for observational seismology. We developed an efficient method to detect earthquakes using waveform similarity that overcomes the disadvantages of existing detection methods. Our method, called Fingerprint And Similarity Thresholding (FAST), can analyze a week of continuous seismic waveform data in less than 2 hours, or 140 times faster than autocorrelation. FAST adapts a data mining algorithm, originally designed to identify similar audio clips within large databases; it first creates compact “fingerprints” of waveforms by extracting key discriminative features, then groups similar fingerprints together within a database to facilitate fast, scalable search for similar fingerprint pairs, and finally generates a list of earthquake detections. FAST detected most (21 of 24) cataloged earthquakes and 68 uncataloged earthquakes in 1 week of continuous data from a station located near the Calaveras Fault in central California, achieving detection performance comparable to that of autocorrelation, with some additional false detections. FAST is expected to realize its full potential when applied to extremely long duration data sets over a distributed network of seismic stations. The widespread application of FAST has the potential to aid in the discovery of unexpected seismic signals, improve seismic monitoring, and promote a greater understanding of a variety of earthquake processes. PMID:26665176

  17. Maximum magnitude earthquakes induced by fluid injection (United States)

    McGarr, A.


    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  18. Multiplicative earthquake likelihood models incorporating strain rates (United States)

    Rhoades, D. A.; Christophersen, A.; Gerstenberger, M. C.


    SUMMARYWe examine the potential for strain-rate variables to improve long-term earthquake likelihood models. We derive a set of multiplicative hybrid earthquake likelihood models in which cell rates in a spatially uniform baseline model are scaled using combinations of covariates derived from earthquake catalogue data, fault data, and strain-rates for the New Zealand region. Three components of the strain rate estimated from GPS data over the period 1991-2011 are considered: the shear, rotational and dilatational strain rates. The hybrid model parameters are optimised for earthquakes of M 5 and greater over the period 1987-2006 and tested on earthquakes from the period 2012-2015, which is independent of the strain rate estimates. The shear strain rate is overall the most informative individual covariate, as indicated by Molchan error diagrams as well as multiplicative modelling. Most models including strain rates are significantly more informative than the best models excluding strain rates in both the fitting and testing period. A hybrid that combines the shear and dilatational strain rates with a smoothed seismicity covariate is the most informative model in the fitting period, and a simpler model without the dilatational strain rate is the most informative in the testing period. These results have implications for probabilistic seismic hazard analysis and can be used to improve the background model component of medium-term and short-term earthquake forecasting models.

  19. New earthquake catalog reexamines Hawaii's seismic history (United States)

    Wright, Thomas L.; Klein, Fred W.


    On April 2,1868, an earthquake of magnitude 7.9 occurred beneath the southern part of the island of Hawaii. The quake, which was felt throughout all of the Hawaiian Islands, had a Modified Mercalli (MM) intensity of XII near its source.The destruction caused by a quake that large is nearly complete. A landslide triggered by the quake buried a small village, killing 31 people, and a tsunami that swept over coastal settlements added to the death toll. We know as much as we do about this and other early earthquakes thanks to detailed records kept by Hawaiian missionaries, including the remarkable diary maintained by the Lyman family that documented every earthquake felt at their home in Hilo between 1833 and 1917 [Wyss et al., 1992].Our analysis of these and other historical records indicates that Hawaii was at least as intensely seismic in the 19th century and first half of the 20th century as in its more recent past, with 26 M ≥6.0 earthquakes occurring from 1823 to 1903 and 20 M ≥6.0 earthquakes from 1904 to 1959. Just five M ≥6.0 earthquakes occurred from 1960 to 1999. The potential damage caused by a repeat of some of the larger historic events could be catastrophic today.

  20. Earthquakes trigger the loss of groundwater biodiversity (United States)

    Galassi, Diana M. P.; Lombardo, Paola; Fiasca, Barbara; di Cioccio, Alessia; di Lorenzo, Tiziana; Petitta, Marco; di Carlo, Piero


    Earthquakes are among the most destructive natural events. The 6 April 2009, 6.3-Mw earthquake in L'Aquila (Italy) markedly altered the karstic Gran Sasso Aquifer (GSA) hydrogeology and geochemistry. The GSA groundwater invertebrate community is mainly comprised of small-bodied, colourless, blind microcrustaceans. We compared abiotic and biotic data from two pre-earthquake and one post-earthquake complete but non-contiguous hydrological years to investigate the effects of the 2009 earthquake on the dominant copepod component of the obligate groundwater fauna. Our results suggest that the massive earthquake-induced aquifer strain biotriggered a flushing of groundwater fauna, with a dramatic decrease in subterranean species abundance. Population turnover rates appeared to have crashed, no longer replenishing the long-standing communities from aquifer fractures, and the aquifer became almost totally deprived of animal life. Groundwater communities are notorious for their low resilience. Therefore, any major disturbance that negatively impacts survival or reproduction may lead to local extinction of species, most of them being the only survivors of phylogenetic lineages extinct at the Earth surface. Given the ecological key role played by the subterranean fauna as decomposers of organic matter and ``ecosystem engineers'', we urge more detailed, long-term studies on the effect of major disturbances to groundwater ecosystems.

  1. Numerical simulations of deformation and movement of blocks within North China in response to 1976 Tangshan earthquake

    Institute of Scientific and Technical Information of China (English)

    白武明; 林邦慧; 陈祖安


    Using methods of discontinuous deformation analysis and finite element (DDA+FEM), this paper simulates dynamic processes of the Tangshan earthquake of 1976, which occurred in the northern North China where its internal blocks apparently interacted. Studies focus upon both the movement and deformation of the blocks, in particular, the Ordos block, and variations of stress states on the boundary faults. The Tangshan earthquake was composed of three events: slipping motions of NNE-striking major fault, NE-striking fault near the northeastern end of the NNE-striking fault, and NW-striking fault on the southeastern side of the NNE-striking fault. Compared with previous studies, our model yields a result that is more agreeable with the configuration of aftershock distributions. A number of data are presented, such as the principle stress field during the earthquake, contours of the maximum shear stress, the strike-slip deformation between blocks near the earthquake focus, time-dependent variations of slips of earthquake-triggered faulting, the maximum slip distance, and stress drops. These results are in accord with the earthquake source mechanism, basic parameters from earthquake wave study, macro-isoseismic line, observed horizontal displacement vectors, etc. The Tangshan earthquake exerted different influences on the adjacent blocks and boundary faults between them, thus resulting in differential movement and deformation. The Ordos block seems to have experienced the small-scale counterclockwise rotation and deformation, but its northeast part, bounded on the east by the Taihangshan and on the north by the Yanshan and Yinshan belts, underwent relatively stronger deformation. The Tangshan earthquake also changed the stress state of boundary faults of the North China, leading to an increase in shear stress and a decrease in normal stress in the NW-trending Zhangjiakou-Penglai fault through Tangshan City and the northern border faults of the Ordos block, and therefore

  2. Earthquakes in Arkansas and vicinity 1699-2010 (United States)

    Dart, Richard L.; Ausbrooks, Scott M.


    This map summarizes approximately 300 years of earthquake activity in Arkansas. It is one in a series of similar State earthquake history maps. Work on the Arkansas map was done in collaboration with the Arkansas Geological Survey. The earthquake data plotted on the map are from several sources: the Arkansas Geological Survey, the Center for Earthquake Research and Information, the National Center for Earthquake Engineering Research, and the Mississippi Department of Environmental Quality. In addition to earthquake locations, other materials presented include seismic hazard and isoseismal maps and related text. Earthquakes are a legitimate concern in Arkansas and parts of adjacent states. Arkansas has undergone a number of significant felt earthquakes since 1811. At least two of these events caused property damage: a magnitude 4.7 earthquake in 1931, and a magnitude 4.3 earthquake in 1967. The map shows all historical and instrumentally located earthquakes in Arkansas and vicinity between 1811 and 2010. The largest historic earthquake in the vicinity of the State was an intensity XI event, on December 16, 1811; the first earthquake in the New Madrid sequence. This violent event and the earthquakes that followed caused considerable damage to the then sparsely settled region.

  3. Retrospective stress-forecasting of earthquakes (United States)

    Gao, Yuan; Crampin, Stuart


    Observations of changes in azimuthally varying shear-wave splitting (SWS) above swarms of small earthquakes monitor stress-induced changes to the stress-aligned vertical microcracks pervading the upper crust, lower crust, and uppermost ~400km of the mantle. (The microcracks are intergranular films of hydrolysed melt in the mantle.) Earthquakes release stress, and an appropriate amount of stress for the relevant magnitude must accumulate before each event. Iceland is on an extension of the Mid-Atlantic Ridge, where two transform zones, uniquely run onshore. These onshore transform zones provide semi-continuous swarms of small earthquakes, which are the only place worldwide where SWS can be routinely monitored. Elsewhere SWS must be monitored above temporally-active occasional swarms of small earthquakes, or in infrequent SKS and other teleseismic reflections from the mantle. Observations of changes in SWS time-delays are attributed to stress-induced changes in crack aspect-ratios allowing stress-accumulation and stress-relaxation to be identified. Monitoring SWS in SW Iceland in 1988, stress-accumulation before an impending earthquake was recognised and emails were exchanged between the University of Edinburgh (EU) and the Iceland Meteorological Office (IMO). On 10th November 1988, EU emailed IMO that a M5 earthquake could occur soon on a seismically-active fault plane where seismicity was still continuing following a M5.1 earthquake six-months earlier. Three-days later, IMO emailed EU that a M5 earthquake had just occurred on the specified fault-plane. We suggest this is a successful earthquake stress-forecast, where we refer to the procedure as stress-forecasting earthquakes as opposed to predicting or forecasting to emphasise the different formalism. Lack of funds has prevented us monitoring SWS on Iceland seismograms, however, we have identified similar characteristic behaviour of SWS time-delays above swarms of small earthquakes which have enabled us to

  4. Dynamic Rupture Simulations Based on the Characterized Source Model of the 2011 Tohoku Earthquake (United States)

    Tsuda, Kenichi; Iwase, Satoshi; Uratani, Hiroaki; Ogawa, Sachio; Watanabe, Takahide; Miyakoshi, Jun'ichi; Ampuero, Jean Paul


    The 2011 Off the Pacific Coast of Tohoku earthquake (Tohoku earthquake, M w 9.0) occurred on the Japan Trench and caused a devastating tsunami. Studies of this earthquake have revealed complex features of its rupture process. In particular, the shallow parts of the fault (near the trench) hosted large slip and long period seismic wave radiation, whereas the deep parts of the rupture (near the coast) hosted smaller slip and strong radiation of short period seismic waves. Understanding such depth-dependent feature of the rupture process of the Tohoku earthquake is necessary as it may occur during future mega-thrust earthquakes in this and other regions. In this study, we investigate the "characterized source model" of the Tohoku earthquake through dynamic rupture simulations. This source model divides the fault plane into several parts characterized by different size and frictional strength (main asperity, background area, etc.) and is widely used in Japan for the prediction of strong ground motion and tsunami through kinematic rupture simulations. Our characterized source model of the Tohoku earthquake comprises a large shallow asperity with moderate frictional strength, small deep asperities with high frictional strength, a background area with low frictional strength, and an area with dynamic weakening close to the trench (low dynamic friction coefficient as arising from, e.g., thermal pressurization). The results of our dynamic rupture simulation reproduce the main depth-dependent feature of the rupture process of the Tohoku earthquake. We also find that the width of the area close to the trench (equal to the distance from the trench to the shallow asperity, interpreted as the size of the accretionary prism) and the presence of dynamic weakening in this area have a significant influence on the final slip distribution. These results are useful to construct characterized source models for other subduction zones with different scale of the accretionary prism, such

  5. Geological and historical evidence of irregular recurrent earthquakes in Japan. (United States)

    Satake, Kenji


    Great (M∼8) earthquakes repeatedly occur along the subduction zones around Japan and cause fault slip of a few to several metres releasing strains accumulated from decades to centuries of plate motions. Assuming a simple 'characteristic earthquake' model that similar earthquakes repeat at regular intervals, probabilities of future earthquake occurrence have been calculated by a government committee. However, recent studies on past earthquakes including geological traces from giant (M∼9) earthquakes indicate a variety of size and recurrence interval of interplate earthquakes. Along the Kuril Trench off Hokkaido, limited historical records indicate that average recurrence interval of great earthquakes is approximately 100 years, but the tsunami deposits show that giant earthquakes occurred at a much longer interval of approximately 400 years. Along the Japan Trench off northern Honshu, recurrence of giant earthquakes similar to the 2011 Tohoku earthquake with an interval of approximately 600 years is inferred from historical records and tsunami deposits. Along the Sagami Trough near Tokyo, two types of Kanto earthquakes with recurrence interval of a few hundred years and a few thousand years had been recognized, but studies show that the recent three Kanto earthquakes had different source extents. Along the Nankai Trough off western Japan, recurrence of great earthquakes with an interval of approximately 100 years has been identified from historical literature, but tsunami deposits indicate that the sizes of the recurrent earthquakes are variable. Such variability makes it difficult to apply a simple 'characteristic earthquake' model for the long-term forecast, and several attempts such as use of geological data for the evaluation of future earthquake probabilities or the estimation of maximum earthquake size in each subduction zone are being conducted by government committees.

  6. Small Stress Change Triggering a Big Earthquake: a Test of the Critical Point Hypothesis for Earthquakes

    Institute of Scientific and Technical Information of China (English)

    万永革; 吴忠良; 周公威


    Whether or not a small stress change can trigger a big earthquake is one of the most important problems related to the critical point hypothesis for earthquakes. We investigate global earthquakes with different focal mechanisms which have different levels of ambient shear stress. This ambient stress level is the stress level required by the earthquakes for their occurrence. Earthquake pairs are studied to see whether the occurrence of the preceding event encourages the occurrence of the succeeding one in terms of the Coulomb stress triggering. It is observed that the stress triggering effect produced by the change of Coulomb failure stress in the same order of magnitudes,about 10-2 MPa, is distinctly different for different focal mechanisms, and thus for different ambient stress levels.For non-strike-slip earthquakes with a relatively low ambient stress level, the triggering effect is more evident,while for strike-slip earthquakes with a relatively high ambient stress level, there is no evident triggering effect.This water level test provides an observational support to the critical point hypothesis for earthquakes.

  7. Accurate Location of the Yao'an Earthquake Sequence and the Yongsheng Earthquake Sequence

    Institute of Scientific and Technical Information of China (English)

    Wang Xinling; Liu Jie; Zhang Guomin; Zhao Cuiping


    The Yao'an Ms6.5 earthquake occurred on Jan. 15, 2000 and the Yongsheng Ms6.0 earthquake occurred on Oct. 27, 2001 in Yunnan Province, China. They are both located in the middle of the Dian block. Their epicenters are close to each other, the tectonic and strain characters of the earthquakes were similar, and there were many aftershocks after the two main shocks. In order to further study the spatial-temporal distributions and fault rupture characters of the main shocks and aftershocks, the latter are located using the Geiger earthquake location algorithm (Geiger) and the double difference earthquake location algorithm (DD) based on the seismic phase data of the two earthquake sequences. They were recorded by two Near Source Digital Seismic Networks (YNSSN and YSNSSN) deployed by the Yunnan Seismological Bureau (YNSB). Then, two main shock parameters were relocated using DD based on the data of larger magnitude aftershocks and the two main shocks that were recorded by the Kunming Regional Digital Seismic Network (KMSN). Combining the spatialtemporal distributions of the two earthquake sequences, the tectonic and strain characters of earthquakes, the rupture processes of the two aftershock sequences along faults are analyzed and discussed contrastively.

  8. Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake (United States)

    Hayes, Gavin P.; Herman, Matthew W.; Barnhart, William D.; Furlong, Kevin P.; Riquelme, Sebástian; Benz, Harley M.; Bergman, Eric; Barrientos, Sergio; Earle, Paul; Samsonov, Sergey


    The seismic gap theory identifies regions of elevated hazard based on a lack of recent seismicity in comparison with other portions of a fault. It has successfully explained past earthquakes (see, for example, ref. 2) and is useful for qualitatively describing where large earthquakes might occur. A large earthquake had been expected in the subduction zone adjacent to northern Chile which had not ruptured in a megathrust earthquake since a M ~8.8 event in 1877. On 1 April 2014 a M 8.2 earthquake occurred within this seismic gap. Here we present an assessment of the seismotectonics of the March–April 2014 Iquique sequence, including analyses of earthquake relocations, moment tensors, finite fault models, moment deficit calculations and cumulative Coulomb stress transfer. This ensemble of information allows us to place the sequence within the context of regional seismicity and to identify areas of remaining and/or elevated hazard. Our results constrain the size and spatial extent of rupture, and indicate that this was not the earthquake that had been anticipated. Significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence.

  9. Influence of cast-in-place floor slab on damage style of frame structures under earthquake%现浇楼板对钢筋混凝土框架结构在地震作用下破坏形式的影响

    Institute of Scientific and Technical Information of China (English)

    阎红霞; 杨庆出; 李吉涛


    Many reinforced concrete (RC) frame structures were severely damaged or even collapsed during the May 12, 2008 great Wenchuan earthquake. Based on survey data collected in Dujiangyan, it was found that plastic hinges appeared at column end, instead of beam end, in many frame structures. This did not coincide with "strong column-weak beam" seismic design criterion. It was believed that one of the main reasons was insufficiently understanding the cast-in-place floor slab effect on frame structures. Applying finite element software ABAQUS, 3D elastic-plastic time history simulation of a "strong beam -weak column" RC frame structure in Dujiangyan was analyzed to probe the influence of cast-in-slab on frame seismic performance from structural view. Results showed that RC frame designed according to current codes usually can not achieve "strong column-weak beam" yield mechanism. The numerical results suggested that the rebar in the width of six times of the plate thickness may take part in calculating the bearing capacity of negative moment at the beam end; the model of a frame structure with floor slab is suitable for analyzing the elastic-plastic deflection of frame structures under rare big earthquakes.%“5.12”汶川地震造成一些钢筋混凝土框架结构损坏甚至倒塌.灾后调查发现,框架结构震害特点也一是柱端而非梁端出现塑性铰的“强梁弱柱”破坏形式,这与结构抗震设计概念中的“强柱弱梁”不符.国内外研究表明现浇楼板增大了梁端抗负弯承载力,但其对整个框架结构屈服机制的影响研究依然不足.针对这种现象,应用有限元软件ABAQUS对汶川地震中都江堰市某典型“强梁弱柱”框架进行三维动力弹塑性时程数值模拟,着重从结构角度上分析了现浇楼板对框架结构抗震性能的影响、探讨了负弯矩作用下梁端有效翼缘的取值.经分析,发现按照目前我国规范设计的框架在遭遇大震时较难实观“

  10. Canonical correlation analysis between post-disaster psychological reaction and their influencing factor in survivors of Wenchuan earthquake%汶川地震幸存者灾后心理反应影响因素的典型相关分析

    Institute of Scientific and Technical Information of China (English)

    王刚; 徐广明; 张本; 牛俊红; 许瑞芬; 于振剑; 王聪哲


    目的 采用典型回归的方法分析不同危险因素共同对经历汶川地震的受灾人群灾后创伤后应激障碍(PTSD)临床症状的影响模式.方法 281例经历过汶川大地震且年龄≥18岁的受灾人群接受了自行编制的调查问卷、PTSD-17项筛查问卷(PCL-C)和艾森克人格问卷成人版的调查.结果 单因素分析结果表明女性更容易经常做噩梦和出现身体反应;神经质水平与易激惹呈正相关.典型相关分析发现内外向分低(r=-0.30)、神经质分低(r=-0.52)、男性(r=-0.73)更容易出现A1痛苦回忆(r=0.31)和丧失兴趣(r=0.34);而较少出现A2经常噩梦(r=-0.45)、A5身体反应(r=-0.44)和C5惊跳反应(r=-0.34).结论 性格特征与性别可能共同决定个体创伤后应激反应是兴奋还是抑制的倾向.%Objective To explore the presenting patterns of clinical symptoms of PTSD influenced by various trauma associates with canonical correlation analysis.Methods Totals of 281 survivors of Wenchuan earthquake aged 18 or older were investigated with the self-designed questionnaire,PTSD-17 screening questionnaire (PCL-C) and Eysenck Personality Questionnaire.Canonical correlation analysis was used to explore the relationships between PTSD symptom items and risk factors related to earthquake psychological traumatic consequences.Results Individuals with low dimension score of Extraversion/Introversion (r =-0.30),low dimensional score of Neuroticism/Stability (r =-0.52) and being male (r =-0.73) were prone to present more symptoms of A1(painful memory) (r =0.31) and B4(losing interest) (0.34).Meanwhile,those people rarely present stress symptoms of A2(frequent nightmares) (r =-0.45),A5(physical reaction) (r =-0.44) and C5(startle reaction) (r =-0.34).Conclusions Personality traits and gender seems to jointly determine the individual's excited or inhibited trauma stress response pattern.

  11. A modified exponential model for reported death toll during earthquakes

    Institute of Scientific and Technical Information of China (English)

    Xinyan Wu; Jianhua Gu


    Reliable earthquake death toll estimate can provide valuable references for disaster relief headquarters and civil administration departments to make arrangement and deployment plan during post-earthquake relief work, thus increasing the efficiency of the relief work to a certain extent. In this study, we acquired the death toll data of Wenchuan earthquake, fitted the data using modified exponential curve and compared the result with that of the exponential function. Experimental verification with Chi-Chi earthquake and Kobe earthquake data shows that the fitted result by modified exponential curve is more satisfactory. The final death toll resulting from future destructive earthquakes can be estimated by the acquired fitting function.

  12. The effects of earthquake measurement concepts and magnitude anchoring on individuals' perceptions of earthquake risk (United States)

    Celsi, R.; Wolfinbarger, M.; Wald, D.


    The purpose of this research is to explore earthquake risk perceptions in California. Specifically, we examine the risk beliefs, feelings, and experiences of lay, professional, and expert individuals to explore how risk is perceived and how risk perceptions are formed relative to earthquakes. Our results indicate that individuals tend to perceptually underestimate the degree that earthquake (EQ) events may affect them. This occurs in large part because individuals' personal felt experience of EQ events are generally overestimated relative to experienced magnitudes. An important finding is that individuals engage in a process of "cognitive anchoring" of their felt EQ experience towards the reported earthquake magnitude size. The anchoring effect is moderated by the degree that individuals comprehend EQ magnitude measurement and EQ attenuation. Overall, the results of this research provide us with a deeper understanding of EQ risk perceptions, especially as they relate to individuals' understanding of EQ measurement and attenuation concepts. ?? 2005, Earthquake Engineering Research Institute.

  13. Physically-based modelling of the competition between surface uplift and erosion caused by earthquakes and earthquake sequences. (United States)

    Hovius, Niels; Marc, Odin; Meunier, Patrick


    Large earthquakes deform Earth's surface and drive topographic growth in the frontal zones of mountain belts. They also induce widespread mass wasting, reducing relief. Preliminary studies have proposed that above a critical magnitude earthquake would induce more erosion than uplift. Other parameters such as fault geometry or earthquake depth were not considered yet. A new seismologically consistent model of earthquake induced landsliding allow us to explore the importance of parameters such as earthquake depth and landscape steepness. We have compared these eroded volume prediction with co-seismic surface uplift computed with Okada's deformation theory. We found that the earthquake depth and landscape steepness to be the most important parameters compared to the fault geometry (dip and rake). In contrast with previous studies we found that largest earthquakes will always be constructive and that only intermediate size earthquake (Mw ~7) may be destructive. Moreover, with landscapes insufficiently steep or earthquake sources sufficiently deep earthquakes are predicted to be always constructive, whatever their magnitude. We have explored the long term topographic contribution of earthquake sequences, with a Gutenberg Richter distribution or with a repeating, characteristic earthquake magnitude. In these models, the seismogenic layer thickness, that sets the depth range over which the series of earthquakes will distribute, replaces the individual earthquake source depth.We found that in the case of Gutenberg-Richter behavior, relevant for the Himalayan collision for example, the mass balance could remain negative up to Mw~8 for earthquakes with a sub-optimal uplift contribution (e.g., transpressive or gently-dipping earthquakes). Our results indicate that earthquakes have probably a more ambivalent role in topographic building than previously anticipated, and suggest that some fault systems may not induce average topographic growth over their locked zone during a

  14. Unusual low-angle normal fault earthquakes after the 2011 Tohoku-oki megathrust earthquake (United States)

    Yagi, Yuji; Okuwaki, Ryo; Enescu, Bogdan; Fukahata, Yukitoshi


    A few low-angle normal fault earthquakes at approximately the depth of the plate interface, with a strike nearly parallel to the trench axis, were detected immediately after the 2011 Tohoku-oki earthquake. After that, however, no such normal fault events have been observed until the occurrence of the 2014 M W 6.6 Fukushima-oki earthquake. Here we analyze the teleseismic body waveforms of the 2014 Fukushima-oki earthquake. We first compare the observed teleseismic body waves of the 2014 Fukushima-oki earthquake with those of the largest previous low-angle normal fault aftershock ( M W 6.6), which occurred on 12 March 2011, and then estimate the centroid depth and moment tensor solution of the 2014 Fukushima-oki earthquake. The teleseismic body waves and moment tensor solution of the 2014 Fukushima-oki earthquake are similar to those of the 2011 normal fault aftershock, which suggests that the 2014 Fukushima-oki earthquake occurred at a similar depth and had a similar mechanism to that of the 2011 aftershock. We detected five low-angle normal fault aftershocks at approximately the depth of the plate interface, with a strike nearly parallel to the trench axis, and confirmed that all of them except for the 2014 Fukushima-oki earthquake occurred within 17 days after the mainshock. The occurrence of these low-angle normal fault events is likely to reflect the reversal of shear stress due to overshooting of slip during the 2011 Tohoku-oki earthquake. We speculate that a fast but heterogeneous recovery of stress state at the plate interface may explain why these events preferentially occurred immediately after the megathrust event, while one of them occurred with a significant delay. In order to better understand the characteristics of stress state in the crust, we have to carefully observe the ongoing seismic activity around this region.

  15. Crowd-Sourced Global Earthquake Early Warning (United States)

    Minson, S. E.; Brooks, B. A.; Glennie, C. L.; Murray, J. R.; Langbein, J. O.; Owen, S. E.; Iannucci, B. A.; Hauser, D. L.


    Although earthquake early warning (EEW) has shown great promise for reducing loss of life and property, it has only been implemented in a few regions due, in part, to the prohibitive cost of building the required dense seismic and geodetic networks. However, many cars and consumer smartphones, tablets, laptops, and similar devices contain low-cost versions of the same sensors used for earthquake monitoring. If a workable EEW system could be implemented based on either crowd-sourced observations from consumer devices or very inexpensive networks of instruments built from consumer-quality sensors, EEW coverage could potentially be expanded worldwide. Controlled tests of several accelerometers and global navigation satellite system (GNSS) receivers typically found in consumer devices show that, while they are significantly noisier than scientific-grade instruments, they are still accurate enough to capture displacements from moderate and large magnitude earthquakes. The accuracy of these sensors varies greatly depending on the type of data collected. Raw coarse acquisition (C/A) code GPS data are relatively noisy. These observations have a surface displacement detection threshold approaching ~1 m and would thus only be useful in large Mw 8+ earthquakes. However, incorporating either satellite-based differential corrections or using a Kalman filter to combine the raw GNSS data with low-cost acceleration data (such as from a smartphone) decreases the noise dramatically. These approaches allow detection thresholds as low as 5 cm, potentially enabling accurate warnings for earthquakes as small as Mw 6.5. Simulated performance tests show that, with data contributed from only a very small fraction of the population, a crowd-sourced EEW system would be capable of warning San Francisco and San Jose of a Mw 7 rupture on California's Hayward fault and could have accurately issued both earthquake and tsunami warnings for the 2011 Mw 9 Tohoku-oki, Japan earthquake.

  16. Development of an Earthquake Impact Scale (United States)

    Wald, D. J.; Marano, K. D.; Jaiswal, K. S.


    With the advent of the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system, domestic (U.S.) and international earthquake responders are reconsidering their automatic alert and activation levels as well as their response procedures. To help facilitate rapid and proportionate earthquake response, we propose and describe an Earthquake Impact Scale (EIS) founded on two alerting criteria. One, based on the estimated cost of damage, is most suitable for domestic events; the other, based on estimated ranges of fatalities, is more appropriate for most global events. Simple thresholds, derived from the systematic analysis of past earthquake impact and response levels, turn out to be quite effective in communicating predicted impact and response level of an event, characterized by alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (major disaster, necessitating international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses exceeding 1M, 10M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness dominate in countries where vernacular building practices typically lend themselves to high collapse and casualty rates, and it is these impacts that set prioritization for international response. In contrast, it is often financial and overall societal impacts that trigger the level of response in regions or countries where prevalent earthquake resistant construction practices greatly reduce building collapse and associated fatalities. Any newly devised alert protocols, whether financial or casualty based, must be intuitive and consistent with established lexicons and procedures. In this analysis, we make an attempt

  17. Fractals and Forecasting in Earthquakes and Finance (United States)

    Rundle, J. B.; Holliday, J. R.; Turcotte, D. L.


    It is now recognized that Benoit Mandelbrot's fractals play a critical role in describing a vast range of physical and social phenomena. Here we focus on two systems, earthquakes and finance. Since 1942, earthquakes have been characterized by the Gutenberg-Richter magnitude-frequency relation, which in more recent times is often written as a moment-frequency power law. A similar relation can be shown to hold for financial markets. Moreover, a recent New York Times article, titled "A Richter Scale for the Markets" [1] summarized the emerging viewpoint that stock market crashes can be described with similar ideas as large and great earthquakes. The idea that stock market crashes can be related in any way to earthquake phenomena has its roots in Mandelbrot's 1963 work on speculative prices in commodities markets such as cotton [2]. He pointed out that Gaussian statistics did not account for the excessive number of booms and busts that characterize such markets. Here we show that both earthquakes and financial crashes can both be described by a common Landau-Ginzburg-type free energy model, involving the presence of a classical limit of stability, or spinodal. These metastable systems are characterized by fractal statistics near the spinodal. For earthquakes, the independent ("order") parameter is the slip deficit along a fault, whereas for the financial markets, it is financial leverage in place. For financial markets, asset values play the role of a free energy. In both systems, a common set of techniques can be used to compute the probabilities of future earthquakes or crashes. In the case of financial models, the probabilities are closely related to implied volatility, an important component of Black-Scholes models for stock valuations. [2] B. Mandelbrot, The variation of certain speculative prices, J. Business, 36, 294 (1963)

  18. Time derivative of earthquake acceleration

    Institute of Scientific and Technical Information of China (English)

    Mai Tong; Guo-Quan Wang; George C.Lee


    Unlike acceleration, velocity, and displacement, the time derivative of acceleration (TDoA) of ground motion has not been extensively studied. In this paper, the basic characteristics of TDoA are evaluated based on records from the 1999Chi-Chi, earthquake (Mw 7.6) and one of its aftershocks (Mw 6.2). It is found that the maximum TDoA at a free-field station was over 31,200 crm/s3 (31.8 g/s); and the duration of "strong" TDoA, between the first and the last time points exceeding 2,000 cm/s3 (2 g/s), was almost one minute near the epicenter area. Since ground TDoA sensors are not commonly available,the time series are calculated by direct numerical differentiation of acceleration time series. Relative error analysis shows that the error is non-transitive and total error is within 4%. The density function of TDoA amplitude, frequency content and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also includes examination of some TDoA responses from a seven-story building and comparison of ground TDoA with the limit TDoA used in the transportation industry for ride comfort. Some potential impacts of TDoA on humans have also been reviewed.

  19. Earthquakes in Mississippi and vicinity 1811-2010 (United States)

    Dart, Richard L.; Bograd, Michael B.E.


    This map summarizes two centuries of earthquake activity in Mississippi. Work on the Mississippi map was done in collaboration with the Mississippi Department of Environmental Quality, Office of Geology. The earthquake data plotted on the map are from several sources: the Mississippi Department of Environmental Quality, the Center for Earthquake Research and Information, the National Center for Earthquake Engineering Research, and the Arkansas Geological Survey. In addition to earthquake locations, other materials include seismic hazard and isoseismal maps and related text. Earthquakes are a legitimate concern in Mississippi and parts of adjacent States. Mississippi has undergone a number of felt earthquakes since 1811. At least two of these events caused property damage: a magnitude 4.7 earthquake in 1931, and a magnitude 4.3 earthquake in 1967. The map shows all historical and instrumentally located earthquakes in Mississippi and vicinity between 1811 and 2010. The largest historic earthquake in the vicinity of the State was an intensity XI event, on December 16, 1811; the first earthquake in the New Madrid sequence. This violent event and the earthquakes that followed caused considerable damage to the then sparsely settled region.

  20. Simulating and analyzing engineering parameters of Kyushu Earthquake, Japan, 1997, by empirical Green function method (United States)

    Li, Zongchao; Chen, Xueliang; Gao, Mengtan; Jiang, Han; Li, Tiefei


    Earthquake engineering parameters are very important in the engineering field, especially engineering anti-seismic design and earthquake disaster prevention. In this study, we focus on simulating earthquake engineering parameters by the empirical Green's function method. The simulated earthquake (MJMA6.5) occurred in Kyushu, Japan, 1997. Horizontal ground motion is separated as fault parallel and fault normal, in order to assess characteristics of two new direction components. Broadband frequency range of ground motion simulation is from 0.1 to 20 Hz. Through comparing observed parameters and synthetic parameters, we analyzed distribution characteristics of earthquake engineering parameters. From the comparison, the simulated waveform has high similarity with the observed waveform. We found the following. (1) Near-field PGA attenuates radically all around with strip radiation patterns in fault parallel while radiation patterns of fault normal is circular; PGV has a good similarity between observed record and synthetic record, but has different distribution characteristic in different components. (2) Rupture direction and terrain have a large influence on 90 % significant duration. (3) Arias Intensity is attenuating with increasing epicenter distance. Observed values have a high similarity with synthetic values. (4) Predominant period is very different in the part of Kyushu in fault normal. It is affected greatly by site conditions. (5) Most parameters have good reference values where the hypo-central is less than 35 km. (6) The GOF values of all these parameters are generally higher than 45 which means a good result according to Olsen's classification criterion. Not all parameters can fit well. Given these synthetic ground motion parameters, seismic hazard analysis can be performed and earthquake disaster analysis can be conducted in future urban planning.

  1. A Statistical Correlation Between Low L-shell Electrons Measured by NOAA Satellites and Strong Earthquakes (United States)

    Fidani, C.


    More than 11 years of the Medium Energy Protons Electrons Detector data from the NOAA polar orbiting satellites were analyzed. Significant electron counting rate fluctuations were evidenced during geomagnetic quiet periods by using a set of adiabatic coordinates. Electron counting rates were compared to earthquakes by defining a seismic event L-shell obtained radially projecting the epicenter geographical positions to a given altitude. Counting rate fluctuations were grouped in every satellite semi-orbit together with strong seismic events and these were chosen with the L-shell coordinates close to each other. Electron data from July 1998 to December 2011 were compared for nearly 1,800 earthquakes with magnitudes larger than or equal to 6, occurring worldwide. When considering 30 - 100 keV energy channels by the vertical NOAA telescopes and earthquake epicenter projections at altitudes greater that 1,300 km, a 4 sigma correlation appeared where time of particle precipitations Tpp occurred 2 - 3 hour prior time of large seismic events Teq. This was in physical agreement with different correlation times obtained from past studies that considered particles with greater energies. The correlation suggested a 4-8 hour advance in preparedness of strong earthquakes influencing the ionosphere. Considering this strong correlation between earthquakes and electron rate fluctuations, and the hypothesis that such fluctuations originated with magnetic disturbances generated underground, a small scale experiment with low cost at ground level is advisable. Plans exists to perform one or more unconventional experiments around an earthquake affected area by private investor in Italy.

  2. Seasonal Water Storage, the Resulting Deformation and Stress, and Occurrence of Earthquakes in California (United States)

    Johnson, C. W.; Burgmann, R.; Fu, Y.; Dutilleul, P.


    In California the accumulated winter snow pack in the Sierra Nevada, reservoirs and groundwater water storage in the Central Valley follow an annual periodic cycle and each contribute to the resulting surface deformation, which can be observed using GPS time series. The ongoing drought conditions in the western U.S. amplify the observed uplift signal as the Earth's crust responds to the mass changes associated with the water loss. The near surface hydrological mass loss can result in annual stress changes of ~1kPa at seismogenic depths. Similarly, small static stress perturbations have previously been associated with changes in earthquake activity. Periodicity analysis of earthquake catalog time series suggest that periods of 4-, 6-, 12-, and 14.24-months are statistically significant in regions of California, and provide documentation for the modulation of earthquake populations at periods of natural loading cycles. Knowledge of what governs the timing of earthquakes is essential to understanding the nature of the earthquake cycle. If small static stress changes influence the timing of earthquakes, then one could expect that events will occur more rapidly during periods of greater external load increases. To test this hypothesis we develop a loading model using GPS derived surface water storage for California and calculate the stress change at seismogenic depths for different faulting geometries. We then evaluate the degree of correlation between the stress models and the seismicity taking into consideration the variable amplitude of stress cycles, the orientation of transient load stress with respect to the background stress field, and the geometry of active faults revealed by focal mechanisms.

  3. Limits on the potential accuracy of earthquake risk evaluations using the L’Aquila (Italy earthquake as an example

    Directory of Open Access Journals (Sweden)

    John Douglas


    Full Text Available This article is concerned with attempting to ‘predict’ (hindcast the damage caused by the L’Aquila 2009 earthquake (Mw 6.3 and, more generally, with the question of how close predicted damage can ever be to observations. Damage is hindcast using a well-established empirical-based approach based on vulnerability indices and macroseismic intensities, adjusted for local site effects. Using information that was available before the earthquake and assuming the same event characteristics as the L’Aquila mainshock, the overall damage is reasonably well predicted but there are considerable differences in the damage pattern. To understand the reasons for these differences, information that was only available after the event were include within the calculation. Despite some improvement in the predicted damage, in particularly by the modification of the vulnerability indices and the parameter influencing the width of the damage distribution, these hindcasts do not match all the details of the observations. This is because of local effects: both in terms of the ground shaking, which is only detectable by the installation of a much denser strong-motion network and a detailed microzonation, and in terms of the building vulnerability, which cannot be modeled using a statistical approach but would require detailed analytical modeling for which calibration data are likely to be lacking. Future studies should concentrate on adjusting the generic components of the approach to make them more applicable to their location of interest. To increase the number of observations available to make these adjustments, we encourage the collection of damage states (and not just habitability classes following earthquakes and also the installation of dense strong-motion networks in built-up areas.

  4. Where was the 1898 Mare Island Earthquake? Insights from the 2014 South Napa Earthquake (United States)

    Hough, S. E.


    The 2014 South Napa earthquake provides an opportunity to reconsider the Mare Island earthquake of 31 March 1898, which caused severe damage to buildings at a Navy yard on the island. Revising archival accounts of the 1898 earthquake, I estimate a lower intensity magnitude, 5.8, than the value in the current Uniform California Earthquake Rupture Forecast (UCERF) catalog (6.4). However, I note that intensity magnitude can differ from Mw by upwards of half a unit depending on stress drop, which for a historical earthquake is unknowable. In the aftermath of the 2014 earthquake, there has been speculation that apparently severe effects on Mare Island in 1898 were due to the vulnerability of local structures. No surface rupture has ever been identified from the 1898 event, which is commonly associated with the Hayward-Rodgers Creek fault system, some 10 km west of Mare Island (e.g., Parsons et al., 2003). Reconsideration of detailed archival accounts of the 1898 earthquake, together with a comparison of the intensity distributions for the two earthquakes, points to genuinely severe, likely near-field ground motions on Mare Island. The 2014 earthquake did cause significant damage to older brick buildings on Mare Island, but the level of damage does not match the severity of documented damage in 1898. The high intensity files for the two earthquakes are more over spatially shifted, with the centroid of the 2014 distribution near the town of Napa and that of the 1898 distribution near Mare Island, east of the Hayward-Rodgers Creek system. I conclude that the 1898 Mare Island earthquake was centered on or near Mare Island, possibly involving rupture of one or both strands of the Franklin fault, a low-slip-rate fault sub-parallel to the Rodgers Creek fault to the west and the West Napa fault to the east. I estimate Mw5.8 assuming an average stress drop; data are also consistent with Mw6.4 if stress drop was a factor of ≈3 lower than average for California earthquakes. I

  5. The 2008 Wenchuan Earthquake and the Rise and Fall of Earthquake Prediction in China (United States)

    Chen, Q.; Wang, K.


    Regardless of the future potential of earthquake prediction, it is presently impractical to rely on it to mitigate earthquake disasters. The practical approach is to strengthen the resilience of our built environment to earthquakes based on hazard assessment. But this was not common understanding in China when the M 7.9 Wenchuan earthquake struck the Sichuan Province on 12 May 2008, claiming over 80,000 lives. In China, earthquake prediction is a government-sanctioned and law-regulated measure of disaster prevention. A sudden boom of the earthquake prediction program in 1966-1976 coincided with a succession of nine M > 7 damaging earthquakes in the densely populated region of the country and the political chaos of the Cultural Revolution. It climaxed with the prediction of the 1975 Haicheng earthquake, which was due mainly to an unusually pronounced foreshock sequence and the extraordinary readiness of some local officials to issue imminent warning and evacuation order. The Haicheng prediction was a success in practice and yielded useful lessons, but the experience cannot be applied to most other earthquakes and cultural environments. Since the disastrous Tangshan earthquake in 1976 that killed over 240,000 people, there have been two opposite trends in China: decreasing confidence in prediction and increasing emphasis on regulating construction design for earthquake resilience. In 1976, most of the seismic intensity XI areas of Tangshan were literally razed to the ground, but in 2008, many buildings in the intensity XI areas of Wenchuan did not collapse. Prediction did not save life in either of these events; the difference was made by construction standards. For regular buildings, there was no seismic design in Tangshan to resist any earthquake shaking in 1976, but limited seismic design was required for the Wenchuan area in 2008. Although the construction standards were later recognized to be too low, those buildings that met the standards suffered much less

  6. Ways to increase the reliability of earthquake loss estimations in emergency mode (United States)

    Frolova, Nina; Bonnin, Jean; Larionov, Valeri; Ugarov, Aleksander


    The lessons of earthquake disasters in Nepal, China, Indonesia, India, Haiti, Turkey and many others show that authorities in charge of emergency response are most often lacking prompt and reliable information on the disaster itself and its secondary effects. Timely and adequate action just after a strong earthquake can result in significant benefits in saving lives and other benefits, especially, in densely populated areas with high level of industrialization. The reliability of rough and rapid information provided by "global systems" (i.e. systems operated without consideration on wherever the earthquake has occurred), in emergency mode is strongly dependent on many factors dealt with input data and simulation models used in such systems. The paper analyses the different factors contribution to the total "error" of fatality estimation in emergency mode. Examples of four strong events in Nepal, Italy, China, Italy allowed to make a conclusion that the reliability of loss estimations is first of all influenced by the uncertainties in event parameters determination (coordinates, magnitude, source depth); this factors' group rating is the highest; as the degree of influence on reliability of loss estimations is equal to about 50%. The second place is taken by the factors' group responsible for macroseismic field simulation; the degree of influence of the group errors is about 30%. The last place is taken by group of factors, which describes the built environment distribution and regional vulnerability functions; the factors' group contributes about 20% to the error of loss estimation. Ways to minimize the influence of different factors on the reliability of loss assessment in near real time are proposed. The first one is to determine the rating of seismological surveys for different zones in attempting to decrease uncertainties in the earthquake parameters input determination in emergency mode. The second one is to "calibrate" the "global systems" drawing advantage

  7. Earthquake Potential in the Zagros Region, Iran

    Directory of Open Access Journals (Sweden)

    Madahizadeh Rohollah


    Full Text Available Seismic strain and b value are used to quantify seismic potential in the Zagros region (Iran. Small b values (0.69 and 0.69 are related to large seismic moment rates (9.96×1017 and 4.12×1017 in southern zones of the Zagros, indicating more frequent large earthquakes. Medium to large b values (0.72 and 0.92 are related to small seismic moment rates (2.94×1016 and 6.80×1016 in middle zones of the Zagros, indicating less frequent large earthquakes. Small b value (0.64 is related to medium seismic moment rate (1.38×1017 in middle to northern zone of the Zagros, indicating frequent large earthquakes. Large b value (0.87 is related to large seismic moment rate (2.29×1017 in northwestern zone, indicating more frequent large earthquakes. Recurrence intervals of large earthquakes (M > 6 are short in southern (10 and 14 years and northwestern (13 years zones, while the recurrence intervals are long in the middle (46 and 114 years and middle to northern (25 years zones.

  8. Roaming earthquakes in China highlight midcontinental hazards (United States)

    Liu, Mian; Wang, Hui


    Before dawn on 28 July 1976, a magnitude (M) 7.8 earthquake struck Tangshan, a Chinese industrial city only 150 kilometers from Beijing (Figure 1a). In a brief moment, the earthquake destroyed the entire city and killed more than 242,000 people [Chen et al., 1988]. More than 30 years have passed, and upon the ruins a new Tangshan city has been built. However, the memory of devastation remains fresh. For this reason, a sequence of recent small earthquakes in the Tangshan region, including an M 4.8 event on 28 May and an M 4.0 event on 18 June 2012, has caused widespread concerns and heated debate in China. In the science community, the debate is whether the recent Tangshan earthquakes are the aftershocks of the 1976 earthquake despite the long gap in time since the main shock or harbingers of a new period of active seismicity in Tangshan and the rest of North China, where seismic activity seems to fluctuate between highs and lows over periods of a few decades [Ma, 1989].

  9. Electrostatically actuated resonant switches for earthquake detection

    KAUST Repository

    Ramini, Abdallah H.


    The modeling and design of electrostatically actuated resonant switches (EARS) for earthquake and seismic applications are presented. The basic concepts are based on operating an electrically actuated resonator close to instability bands of frequency, where it is forced to collapse (pull-in) if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for useful functionalities, such as shutting off gas pipelines in the case of earthquakes, or can be used to activate a network of sensors for seismic activity recording in health monitoring applications. By placing a resonator on a printed circuit board (PCB) of a natural frequency close to that of the earthquake\\'s frequency, we show significant improvement on the detection limit of the EARS lowering it considerably to less than 60% of the EARS by itself without the PCB. © 2013 IEEE.

  10. A Deterministic Approach to Earthquake Prediction

    Directory of Open Access Journals (Sweden)

    Vittorio Sgrigna


    Full Text Available The paper aims at giving suggestions for a deterministic approach to investigate possible earthquake prediction and warning. A fundamental contribution can come by observations and physical modeling of earthquake precursors aiming at seeing in perspective the phenomenon earthquake within the framework of a unified theory able to explain the causes of its genesis, and the dynamics, rheology, and microphysics of its preparation, occurrence, postseismic relaxation, and interseismic phases. Studies based on combined ground and space observations of earthquake precursors are essential to address the issue. Unfortunately, up to now, what is lacking is the demonstration of a causal relationship (with explained physical processes and looking for a correlation between data gathered simultaneously and continuously by space observations and ground-based measurements. In doing this, modern and/or new methods and technologies have to be adopted to try to solve the problem. Coordinated space- and ground-based observations imply available test sites on the Earth surface to correlate ground data, collected by appropriate networks of instruments, with space ones detected on board of Low-Earth-Orbit (LEO satellites. Moreover, a new strong theoretical scientific effort is necessary to try to understand the physics of the earthquake.

  11. Computing Earthquake Probabilities on Global Scales (United States)

    Holliday, James R.; Graves, William R.; Rundle, John B.; Turcotte, Donald L.


    Large devastating events in systems such as earthquakes, typhoons, market crashes, electricity grid blackouts, floods, droughts, wars and conflicts, and landslides can be unexpected and devastating. Events in many of these systems display frequency-size statistics that are power laws. Previously, we presented a new method for calculating probabilities for large events in systems such as these. This method counts the number of small events since the last large event and then converts this count into a probability by using a Weibull probability law. We applied this method to the calculation of large earthquake probabilities in California-Nevada, USA. In that study, we considered a fixed geographic region and assumed that all earthquakes within that region, large magnitudes as well as small, were perfectly correlated. In the present article, we extend this model to systems in which the events have a finite correlation length. We modify our previous results by employing the correlation function for near mean field systems having long-range interactions, an example of which is earthquakes and elastic interactions. We then construct an application of the method and show examples of computed earthquake probabilities.

  12. Loma Prieta Earthquake, October 18, 1989, Part 2 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — On October 17, 1989, a 7.1 magnitude earthquake occurred near Loma Prieta in the Santa Cruz Mountains. This earthquake is also known as the "San Francisco World...

  13. United States Earthquake Intensity Database, 1638-1985 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The United States Earthquake Intensity Database is a collection of damage and felt reports for over 23,000 U.S. earthquakes from 1638-1985. The majority of...

  14. Parent Guidelines for Helping Children After an Earthquake (United States)

    Parent Guidelines for Helping Children after an Earthquake Being in an earthquake is very frightening, and the days, weeks, and months following are very stressful. Your children and family will recover ...

  15. San Fernando Valley California Earthquakes of 1971 and 1994 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This slide set compares two earthquakes that were separated by a distance of 10 miles and a time of 23 years. Disproving the notion that once an earthquake has...

  16. PAGER - Prompt Assessment of Global Earthquakes for Response (United States)

    U.S. Geological Survey, Department of the Interior — PAGER (Prompt Assessment of Global Earthquakes for Response) is an automated system that estimates the impact of significant earthquakes around the world, informing...

  17. Characteristic earthquake model, 1884 -- 2011, R.I.P

    CERN Document Server

    Kagan, Yan Y; Geller, Robert J


    Unfortunately, working scientists sometimes reflexively continue to use "buzz phrases" grounded in once prevalent paradigms that have been subsequently refuted. This can impede both earthquake research and hazard mitigation. Well-worn seismological buzz phrases include "earthquake cycle," "seismic cycle," "seismic gap," and "characteristic earthquake." They all assume that there are sequences of earthquakes that are nearly identical except for the times of their occurrence. If so, the complex process of earthquake occurrence could be reduced to a description of one "characteristic" earthquake plus the times of the others in the sequence. A common additional assumption is that characteristic earthquakes dominate the displacement on fault or plate boundary "segments." The "seismic gap" (or the effectively equivalent "seismic cycle") model depends entirely on the "characteristic" assumption, with the added assumption that characteristic earthquakes are quasi-periodic. However, since the 1990s numerous statistica...

  18. Phase response curves for models of earthquake fault dynamics

    CERN Document Server

    Franović, Igor; Perc, Matjaz; Klinshov, Vladimir; Nekorkin, Vladimir; Kurths, Jürgen


    We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how the profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a ...

  19. Measuring county resilience after the 2008 Wenchuan earthquake

    Directory of Open Access Journals (Sweden)

    X. Li


    Full Text Available The catastrophic earthquake in 2008 has caused serious damage to Wenchuan County and the surrounding area in China. In recent years, great attention has been paid to the resilience of the affected area. This study applied a new framework, the Resilience Inference Measurement (RIM model, to quantify and validate the community resilience of 105 counties in the affected area. The RIM model uses cluster analysis to classify counties into four resilience levels according to the exposure, damage, and recovery conditions, and then applies discriminant analysis to quantify the influence of socioeconomic characteristics on the county resilience. The analysis results show that counties located right at the epicenter had the lowest resilience, but counties immediately adjacent to the epicenter had the highest resilience capacities. Counties that were farther away from the epicenter returned to normal resiliency. The socioeconomic variables, including sex ratio, per capita GDP, percent of ethnic minority, and medical facilities, were identified as the most influential socio-economic characteristics on resilience. This study provides useful information to improve county resilience to earthquakes and support decision-making for sustainable development.

  20. Measuring county resilience after the 2008 Wenchuan earthquake (United States)

    Li, X.; Lam, N.; Qiang, Y.; Li, K.; Yin, L.; Liu, S.; Zheng, W.


    The catastrophic earthquake in 2008 has caused serious damage to Wenchuan County and the surrounding area in China. In recent years, great attention has been paid to the resilience of the affected area. This study applied a new framework, the Resilience Inference Measurement (RIM) model, to quantify and validate the community resilience of 105 counties in the affected area. The RIM model uses cluster analysis to classify counties into four resilience levels according to the exposure, damage, and recovery conditions, and then applies discriminant analysis to quantify the influence of socioeconomic characteristics on the county resilience. The analysis results show that counties located right at the epicenter had the lowest resilience, but counties immediately adjacent to the epicenter had the highest resilience capacities. Counties that were farther away from the epicenter returned to normal resiliency. The socioeconomic variables, including sex ratio, per capita GDP, percent of ethnic minority, and medical facilities, were identified as the most influential socio-economic characteristics on resilience. This study provides useful information to improve county resilience to earthquakes and support decision-making for sustainable development.

  1. The 1638 earthquakes, migratory phenomena and geolinguistic consequences in Calabria

    Directory of Open Access Journals (Sweden)

    J. Trumper


    Full Text Available Two disastrous earthquakes occurred in Calabria (Southern Italy in 1638: on March 27th the first one had a destructive damage area on the Tyrrheniail side of Mid-Calabria. the second one hit the east side of the same region on June 9th. In historical times they are the most intensive seismic events in their respective epicentral areas. so that the reconstruction of their effects is very important for the analysis and assessment of seismic risk. They strongly influenced, moreover, the development of the economy and socio-cultural status of many urban communities. A study of these shocks has been carried out and has implied a thorough re-evaluation of the historical sources of information already known and the exploitation of possible new sources. The two macroseismic fields have been reconstructed: in particular that of the second seismic event, the strongest one in its epicentral area. stimulates a thorough revision of the seismotectonics of the Middle-eastern Calabria. Moreover the reconstruction of the historical facts accompanying and following the earthquakes has furnished elements that help to explain observed anomalies in the spatial distribution of Calabrian dialect phenomena.

  2. Phase response curves for models of earthquake fault dynamics (United States)

    Franović, Igor; Kostić, Srdjan; Perc, Matjaž; Klinshov, Vladimir; Nekorkin, Vladimir; Kurths, Jürgen


    We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how the profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period.

  3. WEGENER: World Earthquake GEodesy Network for Environmental Hazard Research (United States)

    Ozener, Haluk; Zerbini, Susanna; Bastos, Luisa; Becker, Matthias; Meghraoui, Mustapha; Reilinger, Robert


    WEGENER is originally the acronym for Working Group of European Geoscientists for the Establishment of Networks for Earth-science Research. It was founded in March 1981 in response to an appeal delivered at the Journées Luxembourgeoises de Geodynamique in December 1980 to respond with a coordinated European proposal to a NASA Announcement of Opportunity inviting participation in the Crustal Dynamics and Earthquake Research Program. WEGENER, during the past 32 years, has always kept a close contact with the Agencies and Institutions responsible for the development and maintenance of the global space geodetic networks with the aim to make them aware of the scientific needs and outcomes of the project which might have an influence on the general science policy trends. WEGENER was serving as Inter-commission Project 3.2, between Commission 1 and Commission 3, of the International Association of Geodesy (IAG) until 2012. Since then, WEGENER project has became the Sub-commission 3.5 of IAG commission 3, namely Tectonics and Earthquake Geodesy. In this study, we briefly review the accomplishments of WEGENER as originally conceived and outline and justify the new focus of the WEGENER consortium. The remarkable and rapid evolution of the present state of global geodetic monitoring in regard to the precision of positioning capabilities (and hence deformation) and global coverage, the development of InSAR for monitoring strain with unprecedented spatial resolution, and continuing and planned data from highly precise satellite gravity and altimetry missions, encourage us to shift principal attention from mainly monitoring capabilities by a combination of space and terrestrial geodetic techniques to applying existing observational methodologies to the critical geophysical phenomena that threaten our planet and society. Our new focus includes developing an improved physical basis to mitigate earthquake, tsunami, and volcanic risks, and the effects of natural and anthropogenic

  4. Scenario earthquake hazards for the Long Valley Caldera-Mono Lake area, east-central California (United States)

    Chen, Rui; Branum, David M.; Wills, Chris J.; Hill, David P.


    : USGS deterministic seismic hazard analysis program and three Next Generation Ground Motion Attenuation (NGA) models. Ground motion calculations incorporated the potential amplification of seismic shaking by near-surface soils defined by a map of the average shear wave velocity in the uppermost 30 m (VS30) developed by CGS. In addition to ground shaking, earthquakes cause ground failure, which can cause severe damage to buildings and lifelines. Ground failure includes surface fault rupture, liquefaction, and seismically induced landslides. For each earthquake scenario, potential surface fault displacements are estimated using deterministic and probabilistic approaches. Liquefaction occurs when saturated sediments lose their strength because of ground shaking. Zones of potential liquefaction are mapped by incorporating areas where loose sandy sediments, shallow groundwater, and strong earthquake shaking coincide in the earthquake scenario. The process for defining zones of potential landslide and rockfall incorporates rock strength, surface slope, existing landslides, with ground motions caused by the earthquake scenario. Each scenario is illustrated with maps of seismic shaking potential and fault displacement, liquefaction, and landslide potential. Seismic shaking is depicted by the distribution of shaking intensity, peak ground acceleration, and 1.0-second spectral acceleration. One-second spectral acceleration correlates well with structural damage to surface facilities. Acceleration greater than 0.2 g is often associated with strong to violent perceived ground shaking and may cause moderate to heavy damage. The extent of strong shaking is influenced by subsurface fault dip and near surface materials. Strong shaking is more widespread in the hanging wall regions of a normal fault. Larger ground motions also occur where young alluvial sediments amplify the shaking. Both of these effects can lead to strong shaking that extends farther from the fault on the valley side

  5. Relationship between earthquake and volcanic eruption inferred from historical records

    Institute of Scientific and Technical Information of China (English)

    陈洪洲; 高峰; 吴雪娟; 孟宪森


    A large number of seismic records are discovered for the first time in the historical materials about Wudalianchi volcanic group eruption in 1720~1721, which provides us with abundant volcanic earthquake information. Based on the written records, the relationship between earthquake and volcanic eruption is discussed in the paper. Furthermore it is pointed that earthquake swarm is an important indication of volcanic eruption. Therefore, monitoring volcanic earthquakes is of great significance for forecasting volcanic eruption.

  6. Protecting Your Family From Earthquakes-The Seven Steps to Earthquake Safety (in Spanish and English) (United States)

    Developed by American Red Cross, Asian Pacific Fund


    This book is provided here to share an important message on emergency preparedness. Historically, we have suffered earthquakes here in the San Francisco Bay Area that have caused severe hardship for residents and incredible damage to our cities. It is likely we will experience a severe earthquake within the next 30 years. Many of us come from other countries where we have experienced earth- quakes, so we believe that we understand them. However, the way we prepare for earthquakes in our home country may be different from the way it is necessary to prepare for earthquakes here. Very f w people die from collapsing buildings in the Bay Area because most structures are built to stand up to the shaking. But it is quite possible that your family will be without medical care or grocery stores and separated from one another for several days to weeks. It will ultimately be up to you to keep your family safe until help arrives, so we are asking you to join us in learning to take care of your family before, during, and after an earthquake. The first step is to read this book. Everyone in your family, children and adults, can learn how to prepare for an earthquake. Then take advantage of the American Red Cross Earthquake Preparedness training courses offered in your community. These preparedness courses are free, and also offered in Spanish and available to everyone in the community regardless of family history, leg al status, gender, or age. We encourage you to take one of these free training workshops. Look on the back cover for more information. Remember that an earthquake can occur without warning, and the only way that we can reduce the harm caused by earthquakes is to be prepared. Get Prepared!

  7. 1/f and the Earthquake Problem: Scaling constraints to facilitate operational earthquake forecasting (United States)

    Yoder, M. R.; Rundle, J. B.; Glasscoe, M. T.


    The difficulty of forecasting earthquakes can fundamentally be attributed to the self-similar, or '1/f', nature of seismic sequences. Specifically, the rate of occurrence of earthquakes is inversely proportional to their magnitude m, or more accurately to their scalar moment M. With respect to this '1/f problem,' it can be argued that catalog selection (or equivalently, determining catalog constraints) constitutes the most significant challenge to seismicity based earthquake forecasting. Here, we address and introduce a potential solution to this most daunting problem. Specifically, we introduce a framework to constrain, or partition, an earthquake catalog (a study region) in order to resolve local seismicity. In particular, we combine Gutenberg-Richter (GR), rupture length, and Omori scaling with various empirical measurements to relate the size (spatial and temporal extents) of a study area (or bins within a study area), in combination with a metric to quantify rate trends in local seismicity, to the local earthquake magnitude potential - the magnitudes of earthquakes the region is expected to experience. From this, we introduce a new type of time dependent hazard map for which the tuning parameter space is nearly fully constrained. In a similar fashion, by combining various scaling relations and also by incorporating finite extents (rupture length, area, and duration) as constraints, we develop a method to estimate the Omori (temporal) and spatial aftershock decay parameters as a function of the parent earthquake's magnitude m. From this formulation, we develop an ETAS type model that overcomes many point-source limitations of contemporary ETAS. These models demonstrate promise with respect to earthquake forecasting applications. Moreover, the methods employed suggest a general framework whereby earthquake and other complex-system, 1/f type, problems can be constrained from scaling relations and finite extents.

  8. Origin of coda waves: earthquake source resonance

    CERN Document Server

    Liu, Yinbin


    Seismic coda in local earthquake exhibits the characteristics of uniform spatial distribution energy, selective frequency, and slow temporal decay oscillation. It is usually assumed to be the incoherent waves scattered from random heterogeneity in the earth's lithosphere. Here I show by wave field modeling for 1D heterogeneity that seismic coda is related to the natural resonance of earthquake source around the earthquake's focus. This natural resonance is a kind of wave coherent scattering enhancement phenomenon or coupling oscillations happened in steady state regime in strong small-scale heterogeneity. Its resonance frequency is inversely proportional to the heterogeneous scale and contrast and will shift toward lower frequency with increasing random heterogeneous scale and velocity fluctuations. Its energy weakens with decreasing impedance contrast and increasing random heterogeneous scale and velocity fluctuations.

  9. An eyewitness account of the Bhuj earthquake

    Indian Academy of Sciences (India)

    M K Gupta


    The occurrence of a severe earthquake is a rare event with its effect localized in a limited region. There are no prior indications of its occurrence too; hence experiencing such an event is just a matter of chance, which the author had by virtue of his posting at Bhuj. This paper presents a detailed account of observations made in the wake of the Bhuj earthquake of January 26th 2001, describing physical and mental reactions during the earthquake, the post-quake scenario, the nature and cause of damage to buildings, the trend of aftershocks, various deformities, including ruptures and fissures on the surface of the earth, etc. which may be useful for a detailed study of the seismological activity in the region.

  10. Lessons learned from the 1994 Northridge Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Eli, M.W.; Sommer, S.C. [Lawrence Livermore National Lab., CA (United States)


    Southern California has a history of major earthquakes and also has one of the largest metropolitan areas in the United States. The 1994 Northridge Earthquake challenged the industrial facilities and lifetime infrastructure in the northern Los Angeles (LA) area. Lawrence Livermore National Laboratory (LLNL) sent a team of engineers to conduct an earthquake damage investigation in the Northridge area, on a project funded jointly by the United States Nuclear Regulatory Commission (USNRC) and the United States Department of Energy (USDOE). Many of the structures, systems, and components (SSCs) and lifelines that suffered damage are similar to those found in nuclear power plants and in USDOE facilities. Lessons learned from these experiences can have some applicability at commercial nuclear power plants.

  11. Volcanotectonic earthquakes induced by propagating dikes (United States)

    Gudmundsson, Agust


    Volcanotectonic earthquakes are of high frequency and mostly generated by slip on faults. During chamber expansion/contraction earthquakes are distribution in the chamber roof. Following magma-chamber rupture and dike injection, however, earthquakes tend to concentrate around the dike and follow its propagation path, resulting in an earthquake swarm characterised by a number of earthquakes of similar magnitudes. I distinguish between two basic processes by which propagating dikes induce earthquakes. One is due to stress concentration in the process zone at the tip of the dike, the other relates to stresses induced in the walls and surrounding rocks on either side of the dike. As to the first process, some earthquakes generated at the dike tip are related to pure extension fracturing as the tip advances and the dike-path forms. Formation of pure extension fractures normally induces non-double couple earthquakes. There is also shear fracturing in the process zone, however, particularly normal faulting, which produces double-couple earthquakes. The second process relates primarily to slip on existing fractures in the host rock induced by the driving pressure of the propagating dike. Such pressures easily reach 5-20 MPa and induce compressive and shear stresses in the adjacent host rock, which already contains numerous fractures (mainly joints) of different attitudes. In piles of lava flows or sedimentary beds the original joints are primarily vertical and horizontal. Similarly, the contacts between the layers/beds are originally horizontal. As the layers/beds become buried, the joints and contacts become gradually tilted so that the joints and contacts become oblique to the horizontal compressive stress induced by a driving pressure of the (vertical) dike. Also, most of the hexagonal (or pentagonal) columnar joints in the lava flows are, from the beginning, oblique to an intrusive sheet of any attitude. Consequently, the joints and contacts function as potential shear

  12. Earthquake resistant design of rock oil tanks

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, M.; Iwano, M.; Izumi, H.; Shiba, Y.; Sugihara, Y.


    In order to establish a rational procedure of the earthquake resistant design of large rock caverns, such as oil storage tanks on nuclear power plants, experimental and numerical studies were conducted. Dynamic strains during earthquakes were observed on the lining of a railway tunnel constructed in a hard rock mountain, while the seismic motion in the surrounding rock was examined precisely. The observation clarified that the lining strain of the tunnel was linearly and statically related to the rock strain and the ratio of the lining strain to the rock strain was dominated by the relative stiffness of the lining and rock. Based on the results of the earthquake observation, numerical models were proposed for the estimation of the dynamic strains of rock caverns. A good agreement between the calculated strains and the observed ones assured the adequacy of the numerical models.

  13. Earthquake-explosion discrimination using diffusion maps (United States)

    Rabin, N.; Bregman, Y.; Lindenbaum, O.; Ben-Horin, Y.; Averbuch, A.


    Discrimination between earthquakes and explosions is an essential component of nuclear test monitoring and it is also important for maintaining the quality of earthquake catalogues. Currently used discrimination methods provide a partial solution to the problem. In this work, we apply advanced machine learning methods and in particular diffusion maps for modelling and discriminating between seismic signals. Diffusion maps enable us to construct a geometric representation that capture the intrinsic structure of the seismograms. The diffusion maps are applied after a pre-processing step, in which seismograms are converted to normalized sonograms. The constructed low-dimensional model is used for automatic earthquake-explosion discrimination of data that are collected in single seismic stations. We demonstrate our approach on a data set comprising seismic events from the Dead Sea area. The diffusion-based algorithm provides correct discrimination rate that is higher than 90 per cent.

  14. State-of-the-Art for Assessing Earthquake Hazards in the United States. Report 28. Recommended Accelerograms for Earthquake Ground Motions (United States)


    UNAM, Preliminary Report GAA-1A. Quaas, Roberto , Anderson, John G, et al., October 1985. The Michoacan- Guerrero, Mexico Earthquake of September 1985...Skopje. Yugoslavia 1979 Leeds, Arline, ed., November 1980. Reconnaissance Report: Montenegro , Yugoslavia Earthquake, April 15, 1979: Earthquake...the April 15, 1979 Montenegro -Yugoslavia Earthquake: Institute of Earthquake Engineering and Engineering Seismology, University "Kiril and Metodij

  15. 78 FR 64973 - National Earthquake Prediction Evaluation Council (NEPEC) (United States)


    ... Geological Survey National Earthquake Prediction Evaluation Council (NEPEC) AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of meeting. SUMMARY: Pursuant to Public Law 96-472, the National Earthquake... proposed earthquake predictions, on the completeness and scientific validity of the available data...

  16. 77 FR 53225 - National Earthquake Prediction Evaluation Council (NEPEC) (United States)


    ... Geological Survey National Earthquake Prediction Evaluation Council (NEPEC) AGENCY: Department of the... National Earthquake Prediction Evaluation Council (NEPEC) will hold a 1\\1/2\\ day meeting on September 17 and 18, 2012, at the U.S. Geological Survey National Earthquake Information Center (NEIC),...

  17. 76 FR 19123 - National Earthquake Prediction Evaluation Council (NEPEC) (United States)


    ....S. Geological Survey National Earthquake Prediction Evaluation Council (NEPEC) AGENCY: U.S... Earthquake Prediction Evaluation Council (NEPEC) will hold a 1-day meeting on April 16, 2011. The meeting... the Director of the U.S. Geological Survey on proposed earthquake predictions, on the completeness...

  18. Great Hanshin-Awaji (Kobe) Earthquake, January 17, 1995 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Earthquake - At 5:46 A.M. local time on January 17, 1995, a major earthquake occurred near the City of Kobe, Japan. The 6.9 magnitude earthquake had 40 km of...

  19. The Earthquake from 24 September in Moldova and Romania (United States)

    Gaina, Alex; Cristian, Adrian


    On reports the earthquake from 24 September 2016 which took place in Vrancea, Romania in the night and was registered in the Republic of Moldova also. General problems on earthquakes has been discussed. A part of the report discusses and compares (at a popular level) the similarities and differencies between mechanical (acoustic) waves produced by earthquakes and gravitational waves.

  20. 76 FR 61113 - Scientific Earthquake Studies Advisory Committee (United States)


    ....S. Geological Survey Scientific Earthquake Studies Advisory Committee AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake.... Geological Survey (USGS) on matters relating to the USGS's participation in the National Earthquake...

  1. 75 FR 66388 - Scientific Earthquake Studies Advisory Committee (United States)


    ....S. Geological Survey Scientific Earthquake Studies Advisory Committee AGENCY: U.S. Geological Survey. ACTION: Notice of Meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake Studies.... Geological Survey (USGS) on matters relating to the USGS's participation in the National Earthquake...

  2. 78 FR 64973 - Scientific Earthquake Studies Advisory Committee (SESAC) (United States)


    ... Geological Survey Scientific Earthquake Studies Advisory Committee (SESAC) AGENCY: U.S. Geological Survey. ACTION: Notice of meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake Studies... the National Earthquake Hazards Reduction Program. The Committee will receive reports on the status...

  3. 77 FR 12323 - Scientific Earthquake Studies Advisory Committee (United States)


    ....S. Geological Survey Scientific Earthquake Studies Advisory Committee AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of Meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake.... Geological Survey (USGS) on matters relating to the USGS's participation in the National Earthquake...

  4. 77 FR 62523 - Scientific Earthquake Studies Advisory Committee (United States)


    ... Geological Survey Scientific Earthquake Studies Advisory Committee AGENCY: U.S. Geological Survey. ACTION: Notice of Meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake Studies Advisory... the USGS's participation in the National Earthquake Hazards Reduction Program. The Committee...

  5. 78 FR 19004 - Scientific Earthquake Studies Advisory Committee (United States)


    ....S. Geological Survey Scientific Earthquake Studies Advisory Committee AGENCY: U.S. Geological Survey. ACTION: Notice of meeting. SUMMARY: Pursuant to Public Law 106-503, the Scientific Earthquake Studies... Survey (USGS) on matters relating to the USGS's participation in the National Earthquake...

  6. 76 FR 64325 - Advisory Committee on Earthquake Hazards Reduction Meeting (United States)


    ..., to review the conclusions of the National Research Council Report on National Earthquake Resilience... National Research Council Report on National Earthquake Resilience, and to review NEHRP agency updates on... developments in the science and engineering of earthquake hazards reduction; The effectiveness of NEHRP...

  7. Self-Organized Criticality Analysis of Earthquake Model Based on Heterogeneous Networks*

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; ZHANG Gui-Qing; CHEN Tian-Lun


    The original Olami-Feder-Christensen (OFC) model, which displays a robust power-law behavior, is a quasistatic two-dimensional version of the Burridge-Knopoff spring-block model of earthquakes. In this paper, we introduce a modified OFC model based on heterogeneous network, improving the redistribution rule of the original model. It can be seen as a generalization of the original OFC model. We numerically investigate the influence of the parameters θ and β, which respectively control the intensity of the evolutive mechanism of the topological growth and the inner selection dynamics in our networks, and find that there are two distinct phases in the parameter space (θ, β).Meanwhile, we study the influence of the control parameter a either. Increasing a, the earthquake behavior of the model transfers from local to global.

  8. Adaptively smoothed seismicity earthquake forecasts for Italy

    Directory of Open Access Journals (Sweden)

    Yan Y. Kagan


    Full Text Available We present a model for estimation of the probabilities of future earthquakes of magnitudes m ≥ 4.95 in Italy. This model is a modified version of that proposed for California, USA, by Helmstetter et al. [2007] and Werner et al. [2010a], and it approximates seismicity using a spatially heterogeneous, temporally homogeneous Poisson point process. The temporal, spatial and magnitude dimensions are entirely decoupled. Magnitudes are independently and identically distributed according to a tapered Gutenberg-Richter magnitude distribution. We have estimated the spatial distribution of future seismicity by smoothing the locations of past earthquakes listed in two Italian catalogs: a short instrumental catalog, and a longer instrumental and historic catalog. The bandwidth of the adaptive spatial kernel is estimated by optimizing the predictive power of the kernel estimate of the spatial earthquake density in retrospective forecasts. When available and reliable, we used small earthquakes of m ≥ 2.95 to reveal active fault structures and 29 probable future epicenters. By calibrating the model with these two catalogs of different durations to create two forecasts, we intend to quantify the loss (or gain of predictability incurred when only a short, but recent, data record is available. Both forecasts were scaled to five and ten years, and have been submitted to the Italian prospective forecasting experiment of the global Collaboratory for the Study of Earthquake Predictability (CSEP. An earlier forecast from the model was submitted by Helmstetter et al. [2007] to the Regional Earthquake Likelihood Model (RELM experiment in California, and with more than half of the five-year experimental period over, the forecast has performed better than the others.

  9. Is It Possible to Predict Strong Earthquakes? (United States)

    Polyakov, Y. S.; Ryabinin, G. V.; Solovyeva, A. B.; Timashev, S. F.


    The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake a few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on 28 February 2013) recorded at two different sites in the southeastern part of the Kamchatka Peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geophysical system that are believed to precede strong earthquakes. The rodent brain activity signals are selected as potential "immediate" (up to 2 weeks) deterministic precursors because of the recent scientific reports confirming that rodents sense imminent earthquakes and the population-genetic model of K irshvink (Soc Am 90, 312-323, 2000) showing how a reliable genetic seismic escape response system may have developed over the period of several hundred million years in certain animals. The use of brain activity signals, such as electroencephalograms, in contrast to conventional abnormal animal behavior observations, enables one to apply the standard "input-sensor-response" approach to determine what input signals trigger specific seismic escape brain activity responses.

  10. Signals of ENPEMF Used in Earthquake Prediction (United States)

    Hao, G.; Dong, H.; Zeng, Z.; Wu, G.; Zabrodin, S. M.


    The signals of Earth's natural pulse electromagnetic field (ENPEMF) is a combination of the abnormal crustal magnetic field pulse affected by the earthquake, the induced field of earth's endogenous magnetic field, the induced magnetic field of the exogenous variation magnetic field, geomagnetic pulsation disturbance and other energy coupling process between sun and earth. As an instantaneous disturbance of the variation field of natural geomagnetism, ENPEMF can be used to predict earthquakes. This theory was introduced by A.A Vorobyov, who expressed a hypothesis that pulses can arise not only in the atmosphere but within the Earth's crust due to processes of tectonic-to-electric energy conversion (Vorobyov, 1970; Vorobyov, 1979). The global field time scale of ENPEMF signals has specific stability. Although the wave curves may not overlap completely at different regions, the smoothed diurnal ENPEMF patterns always exhibit the same trend per month. The feature is a good reference for observing the abnormalities of the Earth's natural magnetic field in a specific region. The frequencies of the ENPEMF signals generally locate in kilo Hz range, where frequencies within 5-25 kilo Hz range can be applied to monitor earthquakes. In Wuhan, the best observation frequency is 14.5 kilo Hz. Two special devices are placed in accordance with the S-N and W-E direction. Dramatic variation from the comparison between the pulses waveform obtained from the instruments and the normal reference envelope diagram should indicate high possibility of earthquake. The proposed detection method of earthquake based on ENPEMF can improve the geodynamic monitoring effect and can enrich earthquake prediction methods. We suggest the prospective further researches are about on the exact sources composition of ENPEMF signals, the distinction between noise and useful signals, and the effect of the Earth's gravity tide and solid tidal wave. This method may also provide a promising application in

  11. Report of Earthquake Drills with Experiences of Ground Motion in Childcare for Young Children, Japan (United States)

    Yamada, N.


    After the Great East Japan Earthquake of 2011, this disaster has become one of the opportunities to raise awareness of earthquake and tsunami disaster prevention, and the improvement of disaster prevention education is to be emphasized. The influences of these bring the extension to the spatial axis in Japan, and also, it is important to make a development of the education with continuous to the expansion of time axes. Although fire or earthquake drills as the disaster prevention education are often found in Japan, the children and teachers only go from school building to outside. Besides, only the shortness of the time to spend for the drill often attracts attention. The complementary practice education by the cooperation with experts such as the firefighting is practiced, but the verification of the effects is not enough, and it is the present conditions that do not advance to the study either. Although it is expected that improvement and development of the disaster prevention educations are accomplished in future, there are a lot of the problems. Our target is construction and utilization of material contributing to the education about "During the strong motion" in case of the earthquake which may experience even if wherever of Japan. One of the our productions is the handicraft shaking table to utilize as teaching tools of the education to protect the body which is not hurt at the time of strong motion. This made much of simplicity than high reproduction of the earthquake ground motions. We aimed to helping the disaster prevention education including not only the education for young children but also for the school staff and their parents. In this report, the focusing on a way of the non-injured during the time of the earthquake ground motion, and adopting activity of the play, we are going to show the example of the framework of earthquake disaster prevention childcare through the virtual experience. This presentation has a discussion as a practice study with

  12. Some Factors Controlling the Seismic Hazard due to Earthquakes Induced by Fluid Injection at Depth (United States)

    McGarr, A.


    toward the southeast and the earthquakes appear to have been induced by three high-volume injection wells adjacent to this newly-discovered structure. During the past 10 years, as the total volume of injected wastewater has increased, so have the maximum moment magnitudes, starting with an event of M4.5 in September 2001, another of M5 in August 2005, and, most recently, the M5.3 earthquake in August 2011. Interestingly, neither injection rate nor well-head injection pressure appears to influence maximum magnitude. Although it is not feasible at this time to determine the seismic outcome in advance of an injection project, it is, nonetheless, encouraging that upper bounds on seismic moment show a reasonably well-defined linear dependence on total volume of injected fluid.

  13. Simulating Earthquake Early Warning Systems in the Classroom as a New Approach to Teaching Earthquakes (United States)

    D'Alessio, M. A.


    A discussion of P- and S-waves seems an ubiquitous part of studying earthquakes in the classroom. Textbooks from middle school through university level typically define the differences between the waves and illustrate the sense of motion. While many students successfully memorize the differences between wave types (often utilizing the first letter as a memory aide), textbooks rarely give tangible examples of how the two waves would "feel" to a person sitting on the ground. One reason for introducing the wave types is to explain how to calculate earthquake epicenters using seismograms and travel time charts -- very abstract representations of earthquakes. Even when the skill is mastered using paper-and-pencil activities or one of the excellent online interactive versions, locating an epicenter simply does not excite many of our students because it evokes little emotional impact, even in students located in earthquake-prone areas. Despite these limitations, huge numbers of students are mandated to complete the task. At the K-12 level, California requires that all students be able to locate earthquake epicenters in Grade 6; in New York, the skill is a required part of the Regent's Examination. Recent innovations in earthquake early warning systems around the globe give us the opportunity to address the same content standard, but with substantially more emotional impact on students. I outline a lesson about earthquakes focused on earthquake early warning systems. The introductory activities include video clips of actual earthquakes and emphasize the differences between the way P- and S-waves feel when they arrive (P arrives first, but is weaker). I include an introduction to the principle behind earthquake early warning (including a summary of possible uses of a few seconds warning about strong shaking) and show examples from Japan. Students go outdoors to simulate P-waves, S-waves, and occupants of two different cities who are talking to one another on cell phones

  14. Iconography of the 1755 Lisbon Earthquake

    Institute of Scientific and Technical Information of China (English)

    Manuel S. Pinto


    @@ Here is a fine book with a timely publication date: 2005 marked the 250th anniversary of the great Lisbon earthquake. Among the many books and papers that were published about the catastrophe in 2005, in Portugal and elsewhere, Iconography of the 1755 Lisbon Earthquake stands out because of its excellent illustrations and a most readable text. Intended for readers interested in the history of geological sciences, and also for those interested in natural catastrophes that generated philosophical and theological controversies in Europe, the book commemorates the event in a truly distinctive way.

  15. Earthquakes induced by deep penetrating bombing?

    Institute of Scientific and Technical Information of China (English)

    Serguei Yu. Balassanian


    The data of M≥5 earthquakes occurred in one year before and after 4 deep penetrating bombs in the region within 500 km and 1 000 km from the shooting site are presented. The 4 bombs are those happened in 1999 Kosovo of Yugoslavia, the 1991 Baghdad of Iraq, the 2001 Tora Bora of Afghanistan, and the 2003 Kirkuk of Iraq, respectively. The data indicate that the deep penetrating bombs may have remotely triggered some earthquakes. The deep penetrating bombs in seismically active regions should be forbidden.

  16. An Ising model for earthquake dynamics

    Directory of Open Access Journals (Sweden)

    A. Jiménez


    Full Text Available This paper focuses on extracting the information contained in seismic space-time patterns and their dynamics. The Greek catalog recorded from 1901 to 1999 is analyzed. An Ising Cellular Automata representation technique is developed to reconstruct the history of these patterns. We find that there is strong correlation in the region, and that small earthquakes are very important to the stress transfers. Finally, it is demonstrated that this approach is useful for seismic hazard assessment and intermediate-range earthquake forecasting.

  17. Evaluation and cataloging of Korean historical earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kew Hwa; Han, Young Woo; Lee, Jun Hui; Park, Ji Eok; Na, Kwang Wooing; Shin, Byung Ju [The Reaearch Institute of Basic Sciences, Seoul Nationl Univ., Seoul (Korea, Republic of)


    Historical earthquake data of the Korean Peninsula which are very important is evaluating seismicity and seismic hazard of the peninsula were collected and analyzed by seismologist and historian. A preliminary catalog of Korean historical earthquake data translated in English was made. Felt places of 528 events felt at more than 2 places were indicated on maps and MMI III isoseismal were drawn for 52 events of MMI{>=}VII. Epicenters and intensities of these MMI{>=}VII events were estimated from these isoseismal maps.

  18. Light for Earthquake Prediction:Shocks before the L'Aquila Earthquake of April 6,2009

    Institute of Scientific and Technical Information of China (English)

    Li Li; Chen Yong


    The temporal-spatial distribution of mid-small earthquakes in Italy and its surroundings from January 1 to April 5,2009 shows that there were significant foreshocks before the moderate L'Aquila earthquake of April 6,2009.The enhancement of frequency and intensity of small earthquakes and their concentrating tendency to the future main shock have provided a comprehensive case for digging methods of earthquake forecasting with foreshocks.

  19. Visco-elastic stress triggering model of Tangshan earthquake sequence

    Institute of Scientific and Technical Information of China (English)

    WAN Yong-ge; SHEN Zheng-kang; ZENG Yue-hua; SHENG Shu-zhong; XU Xiao-feng


    We calculated the Coulomb failure stress change generated by the 1976 Tangshan earthquake that is projected onto the fault planes and slip directions of large subsequent aftershocks. Results of previous studies on the seismic failure distribution, crustal velocity and viscosity structures of the Tangshan earthquake are used as model constraints. Effects of the local pore fluid pressure and impact of soft medium near the fault are also considered. Our result shows that the subsequent Luanxian and Ninghe earthquakes occurred in the regions with a positive Coulomb failure stress produced by the Tangshan earthquake. To study the triggering effect of the Tangshan, Luanxian, and Ninghe earthquakes on the follow-up small earthquakes, we first evaluate the possible focal mechanisms of small earthquakes according to the regional stress field and co-seismic slip distributions derived from previous studies, assuming the amplitude of regional tectonic stress as 10 MPa. By projecting the stress changes generated by the above three earthquakes onto the possible fault planes and slip directions of small earthquakes, we find that the "butterfly" distribution pattern of increased Coulomb failure stress is consistent with the spatial distribution of follow-up earthquakes, and 95% of the aftershocks occurred in regions where Coulomb failure stresses increase, indicating that the former large earthquakes modulated occurrences of follow-up earthquakes in the Tangshan earthquake sequence. This result has some significance in rapid assessment of aftershock hazard after a large earthquake. If detailed failure distribution, seismogenic fault in the focal area and their slip features can be rapidly determined after a large earthquake, our algorithm can be used to predict the locations of large aftershocks.

  20. Post traumatic stress disorder and coping in a sample of adult survivors of the Italian earthquake. (United States)

    Cofini, V; Carbonelli, A; Cecilia, M R; Binkin, N; di Orio, F


    The aim was to investigate the prevalence of post traumatic stress disorder (PTSD) in people who had left their damaged homes and were still living in temporary housing more than a year after the April 2009 L'Aquila (Italy) earthquake. In addition, we evaluated the differences in coping strategies implemented by persons who had and who did not have PTSD. A cross-sectional prevalence study was carried out on a sample of 281 people aged >18 years and living in temporary housing after the earthquake. The questionnaires used include the Davidson Trauma Scale and the Brief Cope. The prevalence of PTSD was 43%. Women and the non-employed were more vulnerable to PTSD, while, age and level of education were not associated with PTSD. Those with PTSD symptoms often employed maladaptive coping strategies for dealing with earthquake and had the highest scores in the domains of denial, venting, behavioral disengagement, self-blame. By contrast, those without PTSD generally had more adaptive coping mechanisms. Adults who were living in temporary housing after the earthquake experienced high rates of PTSD. The difference in coping mechanisms between those who have PTSD and those who do not also suggests that they influence the likeliness of developing PTSD.

  1. Critical earthquake load inputs for multi-degree-of-freedom inelastic structures (United States)

    Moustafa, Abbas


    The problem of modeling earthquake ground motions as design inputs for multi-degree-of-freedom inelastic structures is studied. The earthquake acceleration is expressed as a Fourier series modulated by an envelope function. The coefficients of the series representation are calculated such that the structure inelastic deformation is maximized subjected to predefined constraints. These constraints are taken to reflect known characteristics of recorded earthquakes such as upper bounds on the energy and peak values of the ground acceleration, velocity and displacement and upper and lower limits on the Fourier spectra of the ground acceleration. The material stress-strain behavior is modeled using bilinear and elastic-plastic relations. The resulting nonlinear optimization problem is solved by using the sequential quadratic optimization method. Issues related to various forms of energy dissipated by the inelastic structure are explored. The study also examines the effect of nonlinear damping models and the influence of the strain hardening ratio (ratio of the post-yield stiffness to the pre-yield stiffness) on the derived optimal earthquake and associated inelastic deformation. The formulation is demonstrated for a two-storey inelastic building frame with nonlinear damping.

  2. Fluid regime in the source and preparation area of an earthquake (United States)

    Kissin, I. G.


    Peculiarities of the fluid regime in the source and in the area of preparation of an earthquake which accommodates the evolution of the precursors are considered. The qualitative characteristics and the conditions of migration of the fluids, as well as their influence on the disjunctive deformations of the crust are discussed. During the development of the earthquake source, the fluid regime in this area depends on the redistribution of the fluids and their inflow from the outside. The fluid inflow and the increase in the fluid pressure are mainly due to the filtering from the subvertical permeable faults and the metamorphic dehydration of the rocks in the walls of the main fault. The fluids may also be supplied to the source from the near-surface horizons, and most of the induced earthquakes are associated with this process. These earthquakes can be considered as large-scale natural experiments which can shed light on the contribution of fluids in this phenomenon. A particular role in the mechanism of natural seismicity is played by the inflow of high-pressure fluids through the faults from the deep zones of the section.

  3. Centrifuge model test on earthquake-induced differential settlement of foundation on cohesive ground

    Institute of Scientific and Technical Information of China (English)

    ZHOU YanGuo; CHEN YunMin; SHAMOTO Yasuhiro; HOTTA Hiroyuki


    Dynamic centrifuge model test was conducted to study the earthquake-induced differential settlement of foundation on cohesive ground, and the influence of asymmetry of building was investigated. During the experiment, the overconsolidated kaolin clay ground with a three-dimensional asymmetrical structure model was shaken by a basically balanced input motion, and bender elements were used to measure shear wave velocities of model ground to reveal the soil fabric evolution during and after shaking. The test results show that, the total seismic settlement of foundation is composed of instantaneous and long-term post-earthquake settlements, and most of the differential settlement occurs immediately after the earthquake while the post-earthquake settlement is relatively uniform despite its large amplitude. The asymmetry of building affects the settlement behavior considerably. Compared with 1- or 2-dimensional structures, more evident differential settlement occurs under three-dimensional asymmetrical building during shaking, which accounts for one-half of the total seismic settlements and results in complex spatial tilting effects of foundation.

  4. Preliminary result of earthquake hypocenter determination using hypoellipse around western Java region (United States)

    Supendi, Pepen; Nugraha, Andri Dian


    West Java region is located in high seismicity and active tectonic setting region influenced by subducting Indo-Australian plate beneath Eurasia plate. There are several on land active faults namely Cimandiri fault, Lembang fault, and Baribis fault in the region. MCGA earthquake data catalog from 2009 to 2014 shows the earthquakes were located not only around active faults but also relatively far away from the active faults in West Java region. In this study, we determined the earthquake location through re-picking of P-and S-wave arrival times recording by MCGA network. Earthquake location was determined by using Hypoellipse code that employs a single event determination method. We then relocated the events using hypocenter double-difference method. We also have been conducting focal mechanism analysis to estimate the type of fault slip. Our preliminary results show generally the epicenter location were distributed around the on land active fault which have the focus depth less than 30 km. For ongoing and future works, we have been determining focal mechanism of selected event related to on land active fault for this region..

  5. Centrifuge model test on earthquake-induced differential settlement of foundation on cohesive ground

    Institute of Scientific and Technical Information of China (English)

    SHAMOTO; Yasuhiro; HOTTA; Hiroyuki


    Dynamic centrifuge model test was conducted to study the earthquake-induced differential settlement of foundation on cohesive ground, and the influence of asymmetry of building was investigated. During the experiment, the overconsolidated kaolin clay ground with a three-dimensional asymmetrical structure model was shaken by a basically balanced input motion, and bender elements were used to measure shear wave velocities of model ground to reveal the soil fabric evolution during and after shaking. The test results show that, the total seismic settlement of foundation is composed of instantaneous and long-term post-earthquake settlements, and most of the differential settlement occurs immediately after the earthquake while the post-earthquake settlement is relatively uniform despite its large amplitude. The asymmetry of building affects the settlement behavior considerably. Compared with 1-or 2-dimensional structures, more evident differential settlement occurs under threedimensional asymmetrical building during shaking, which accounts for one-half of the total seismic settlements and results in complex spatial tilting effects of foundation.

  6. The Global Earthquake Model - Past, Present, Future (United States)

    Smolka, Anselm; Schneider, John; Stein, Ross


    The Global Earthquake Model (GEM) is a unique collaborative effort that aims to provide organizations and individuals with tools and resources for transparent assessment of earthquake risk anywhere in the world. By pooling data, knowledge and people, GEM acts as an international forum for collaboration and exchange. Sharing of data and risk information, best practices, and approaches across the globe are key to assessing risk more effectively. Through consortium driven global projects, open-source IT development and collaborations with more than 10 regions, leading experts are developing unique global datasets, best practice, open tools and models for seismic hazard and risk assessment. The year 2013 has seen the completion of ten global data sets or components addressing various aspects of earthquake hazard and risk, as well as two GEM-related, but independently managed regional projects SHARE and EMME. Notably, the International Seismological Centre (ISC) led the development of a new ISC-GEM global instrumental earthquake catalogue, which was made publicly available in early 2013. It has set a new standard for global earthquake catalogues and has found widespread acceptance and application in the global earthquake community. By the end of 2014, GEM's OpenQuake computational platform will provide the OpenQuake hazard/risk assessment software and integrate all GEM data and information products. The public release of OpenQuake is planned for the end of this 2014, and will comprise the following datasets and models: • ISC-GEM Instrumental Earthquake Catalogue (released January 2013) • Global Earthquake History Catalogue [1000-1903] • Global Geodetic Strain Rate Database and Model • Global Active Fault Database • Tectonic Regionalisation Model • Global Exposure Database • Buildings and Population Database • Earthquake Consequences Database • Physical Vulnerabilities Database • Socio-Economic Vulnerability and Resilience Indicators • Seismic

  7. Earthquake probabilities: theoretical assessments and reality (United States)

    Kossobokov, V. G.


    It is of common knowledge that earthquakes are complex phenomena which classification and sizing remain serious problems of the contemporary seismology. In general, their frequency-magnitude distribution exhibit power law scaling. This scaling differs significantly when different time and/or space domains are considered. At the scale of a particular earthquake rupture zone the frequency of similar size events is usually estimated to be about once in several hundred years. Evidently, contemporary seismology does not possess enough reported instrumental data for any reliable quantification of an earthquake probability at a given place of expected event. Regretfully, most of the state-of-the-art theoretical approaches to assess probability of seismic events are based on trivial (e.g. Poisson, periodic, etc) or, conversely, delicately-designed (e.g. STEP, ETAS, etc) models of earthquake sequences. Some of these models are evidently erroneous, some can be rejected by the existing statistics, and some are hardly testable in our life-time. Nevertheless such probabilistic counts including seismic hazard assessment and earthquake forecasting when used on practice eventually mislead to scientifically groundless advices communicated to decision makers and inappropriate decisions. As a result, the population of seismic regions continues facing unexpected risk and losses. The international project Global Earthquake Model (GEM) is on the wrong track, if it continues to base seismic risk estimates on the standard, mainly probabilistic, methodology to assess seismic hazard. It is generally accepted that earthquakes are infrequent, low-probability events. However, they keep occurring at earthquake-prone areas with 100% certainty. Given the expectation of seismic event once per hundred years, the daily probability of occurrence on a certain date may range from 0 to 100% depending on a choice of probability space (which is yet unknown and, therefore, made by a subjective lucky chance

  8. Trends in global earthquake loss (United States)

    Arnst, Isabel; Wenzel, Friedemann; Daniell, James


    Based on the CATDAT damage and loss database we analyse global trends of earthquake losses (in current values) and fatalities for the period between 1900 and 2015 from a statistical perspective. For this time period the data are complete for magnitudes above 6. First, we study the basic statistics of losses and find that losses below 10 bl. US satisfy approximately a power law with an exponent of 1.7 for the cumulative distribution. Higher loss values are modelled with the General Pareto Distribution (GPD). The 'transition' between power law and GPD is determined with the Mean Excess Function. We split the data set into a period of pre 1955 and post 1955 loss data as in those periods the exposure is significantly different due to population growth. The Annual Average Loss (AAL) for direct damage for events below 10 bl. US differs by a factor of 6, whereas the incorporation of the extreme loss events increases the AAL from 25 bl. US/yr to 30 bl. US/yr. Annual Average Deaths (AAD) show little (30%) difference for events below 6.000 fatalities and AAD values of 19.000 and 26.000 deaths per year if extreme values are incorporated. With data on the global Gross Domestic Product (GDP) that reflects the annual expenditures (consumption, investment, government spending) and on capital stock we relate losses to the economic capacity of societies and find that GDP (in real terms) grows much faster than losses so that the latter one play a decreasing role given the growing prosperity of mankind. This reasoning does not necessarily apply on a regional scale. Main conclusions of the analysis are that (a) a correct projection of historic loss values to nowadays US values is critical; (b) extreme value analysis is mandatory; (c) growing exposure is reflected in the AAL and AAD results for the periods pre and post 1955 events; (d) scaling loss values with global GDP data indicates that the relative size - from a global perspective - of losses decreases rapidly over time.

  9. 地震对日本短期石油市场的影响——日本地震引发的核危机将阻碍其今后的核能发展,以核能为主的能源政策很可能将被调整%Influence of Earthquake on Japan's Short-term Oil Market------The earthquake-triggered nuclear crisis affects Japan's nu

    Institute of Scientific and Technical Information of China (English)


    受地震影响,日本电力业遭受重创,引发的核危机将阻碍其今后的核能发展,以核能利用为主的能源政策很可能将被调整。短期内,日本石油需求预计将减少,2011年日本主要石油燃料需求将同比下降0.5%,至558万bbl/d;但用于发电的原油需求将大幅增加,同比增长64.7%。震后,日本采取了动用原油储备、提高炼厂石油加工能力、停止产品出口转销国内市场、增加石油产品进口等应急措施,预计2011年下半年炼油公司有望恢复产品出口。%The earthquake has badly weakened the Japanese power industry, triggering the nuclear crisis that affected the country's nuclear energy development. The energy policy focusing on utilization of nuclear energy is likely to be adjusted. Japan's oil demand i

  10. Intensity earthquake scenario (scenario event - a damaging earthquake with higher probability of occurrence) for the city of Sofia (United States)

    Aleksandrova, Irena; Simeonova, Stela; Solakov, Dimcho; Popova, Maria


    Among the many kinds of natural and man-made disasters, earthquakes dominate with regard to their social and economical impact on the urban environment. Global seismic risk to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas around the world is often associated with the construction of seismically unsafe buildings and infrastructures, and undertaken with an insufficient knowledge of the regional seismicity peculiarities and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The earthquake scenarios are intended as a basic input for developing detailed earthquake damage scenarios for the cities and can be used in earthquake-safe town and infrastructure planning. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia area that is the most populated (the population is of more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=9-10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK). Almost a century later (95 years) an earthquake of moment magnitude 5.6 (I0=7-8 MSK) hit the city of Sofia, on May 22nd, 2012. In the present study as a deterministic scenario event is considered a damaging earthquake with higher probability of occurrence that could affect the city with intensity less than or equal to VIII

  11. Analysis on Double-difference Earthquake Location and the Seismicity Pattern of the Yangjiang Earthquake Sequences

    Institute of Scientific and Technical Information of China (English)

    Kang Ying; Yang Xuan; Huang Wenhui; Chen Xing; Chen Guimei; Lin Wei; Wu Huadeng


    The locations of about 400 earthquakes in Yangjiang, Guangdong Province are determined using the double, difference earthquake location algorithm (DDA). The seismicity pattern becomes concentrated from discrete grids. The rupture characteristics of the Yangjiang earthquake sequence show a conjugated distribution in NW and NE directions. The major distribution trends NE and dips NE with an angle of 30 and a length of 30km,and the minor distribution trends NW and dips SE with an angle of 30 and a length of 201on. The focal depth is 5km~15km. The distribution of the Enping earthquake sequence,which is not far from Yangjiang,is NW-trending. The relationship between hypocenter distribution and geological structure is discussed.

  12. Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake (United States)

    Minson, Sarah E.; Lee, William H.K.


    Locating earthquakes from the beginning of the modern instrumental period is complicated by the fact that there are few good-quality seismograms and what traveltimes do exist may be corrupted by both large phase-pick errors and clock errors. Here, we outline a Bayesian approach to simultaneous inference of not only the hypocentre location but also the clock errors at each station and the origin time of the earthquake. This methodology improves the solution for the source location and also provides an uncertainty analysis on all of the parameters included in the inversion. As an example, we applied this Bayesian approach to the well-studied 1909 Mw 7 Taipei earthquake. While our epicentre location and origin time for the 1909 Taipei earthquake are consistent with earlier studies, our focal depth is significantly shallower suggesting a higher seismic hazard to the populous Taipei metropolitan area than previously supposed.

  13. Network similarity and statistical analysis of earthquake seismic data

    CERN Document Server

    Deyasi, Krishanu; Banerjee, Anirban


    We study the structural similarity of earthquake networks constructed from seismic catalogs of different geographical regions. A hierarchical clustering of underlying undirected earthquake networks is shown using Jensen-Shannon divergence in graph spectra. The directed nature of links indicates that each earthquake network is strongly connected, which motivates us to study the directed version statistically. Our statistical analysis of each earthquake region identifies the hub regions. We calculate the conditional probability of the forthcoming occurrences of earthquakes in each region. The conditional probability of each event has been compared with their stationary distribution.

  14. Earth tides can trigger shallow thrust fault earthquakes. (United States)

    Cochran, Elizabeth S; Vidale, John E; Tanaka, Sachiko


    We show a correlation between the occurrence of shallow thrust earthquakes and the occurrence of the strongest tides. The rate of earthquakes varies from the background rate by a factor of 3 with the tidal stress. The highest correlation is found when we assume a coefficient of friction of mu = 0.4 for the crust, although we see good correlation for mu between 0.2 and 0.6. Our results quantify the effect of applied stress on earthquake triggering, a key factor in understanding earthquake nucleation and cascades whereby one earthquake triggers others.

  15. Method study of classification and gradation of earthquake disasters

    Institute of Scientific and Technical Information of China (English)

    MAO Guo-min; GU Jian-hua; WU Xin-yan


    Based on data of earthquake disaster events during 1954~2005 in the Chinese mainland, the classification and gradation of earthquake disasters have been studied by multivariate statistical analysis. Three fundamental structures of earthquake disasters have been found and an FAPE (factor analysis-principal component-equamax rotation) classification model and an HCWS (hierarchical cluster-ward method-seuclid) gradation model have been constructed. Earthquake disasters are divided into eight classes and five grades respectively in the models, which give a reasonable explanation to the phenomenon of earthquake disasters.

  16. Implications of the Regional Earthquake Likelihood Models test of earthquake forecasts in California

    Directory of Open Access Journals (Sweden)

    Michael Karl Sachs


    Full Text Available The Regional Earthquake Likelihood Models (RELM test was the first competitive comparison of prospective earthquake forecasts. The test was carried out over 5 years from 1 January 2006 to 31 December 2010 over a region that included all of California. The test area was divided into 7682 0.1°x0.1° spatial cells. Each submitted forecast gave the predicted numbers of earthquakes Nemi larger than M=4.95 in 0.1 magnitude bins for each cell. In this paper we present a method that separates the forecast of the number of test earthquakes from the forecast of their locations. We first obtain the number Nem of forecast earthquakes in magnitude bin m. We then determine the conditional probability λemi=Nemi/Nem that an earthquake in magnitude bin m will occur in cell i. The summation of λemi over all 7682 cells is unity. A random (no skill forecast gives equal values of λemi for all spatial cells and magnitude bins. The skill of a forecast, in terms of the location of the earthquakes, is measured by the success in assigning large values of λemi to the cells in which earthquakes occur and low values of λemi to the cells where earthquakes do not occur. Thirty-one test earthquakes occurred in 27 different combinations of spatial cells i and magnitude bins m, we had the highest value of λemi for that mi cell. We evaluate the performance of eleven submitted forecasts in two ways. First, we determine the number of mi cells for which the forecast λemi was the largest, the best forecast is the one with the highest number. Second, we determine the mean value of λemi for the 27 mi cells for each forecast. The best forecast has the highest mean value of λemi. The success of a forecast during the test period is dependent on the allocation of the probabilities λemi between the mi cells, since the sum over the mi cells is unity. We illustrate the forecast distributions of λemi and discuss their differences. We conclude that the RELM test was successful in

  17. Repeating Earthquakes Following an Mw 4.4 Earthquake Near Luther, Oklahoma (United States)

    Clements, T.; Keranen, K. M.; Savage, H. M.


    An Mw 4.4 earthquake on April 16, 2013 near Luther, OK was one of the earliest M4+ earthquakes in central Oklahoma, following the Prague sequence in 2011. A network of four local broadband seismometers deployed within a day of the Mw 4.4 event, along with six Oklahoma netquake stations, recorded more than 500 aftershocks in the two weeks following the Luther earthquake. Here we use HypoDD (Waldhauser & Ellsworth, 2000) and waveform cross-correlation to obtain precise aftershock locations. The location uncertainty, calculated using the SVD method in HypoDD, is ~15 m horizontally and ~ 35 m vertically. The earthquakes define a near vertical, NE-SW striking fault plane. Events occur at depths from 2 km to 3.5 km within the granitic basement, with a small fraction of events shallower, near the sediment-basement interface. Earthquakes occur within a zone of ~200 meters thickness on either side of the best-fitting fault surface. We use an equivalency class algorithm to identity clusters of repeating events, defined as event pairs with median three-component correlation > 0.97 across common stations (Aster & Scott, 1993). Repeating events occur as doublets of only two events in over 50% of cases; overall, 41% of earthquakes recorded occur as repeating events. The recurrence intervals for the repeating events range from minutes to days, with common recurrence intervals of less than two minutes. While clusters occur in tight dimensions, commonly of 80 m x 200 m, aftershocks occur in 3 distinct ~2km x 2km-sized patches along the fault. Our analysis suggests that with rapidly deployed local arrays, the plethora of ~Mw 4 earthquakes occurring in Oklahoma and Southern Kansas can be used to investigate the earthquake rupture process and the role of damage zones.

  18. Simulating Earthquakes for Science and Society: New Earthquake Visualizations Ideal for Use in Science Communication (United States)

    de Groot, R. M.; Benthien, M. L.


    The Southern California Earthquake Center (SCEC) has been developing groundbreaking computer modeling capabilities for studying earthquakes. These visualizations were initially shared within the scientific community but have recently have gained visibility via television news coverage in Southern California. These types of visualizations are becoming pervasive in the teaching and learning of concepts related to earth science. Computers have opened up a whole new world for scientists working with large data sets, and students can benefit from the same opportunities (Libarkin &Brick, 2002). Earthquakes are ideal candidates for visualization products: they cannot be predicted, are completed in a matter of seconds, occur deep in the earth, and the time between events can be on a geologic time scale. For example, the southern part of the San Andreas fault has not seen a major earthquake since about 1690, setting the stage for an earthquake as large as magnitude 7.7 -- the "big one." Since no one has experienced such an earthquake, visualizations can help people understand the scale of such an event. Accordingly, SCEC has developed a revolutionary simulation of this earthquake, with breathtaking visualizations that are now being distributed. According to Gordin and Pea (1995), theoretically visualization should make science accessible, provide means for authentic inquiry, and lay the groundwork to understand and critique scientific issues. This presentation will discuss how the new SCEC visualizations and other earthquake imagery achieve these results, how they fit within the context of major themes and study areas in science communication, and how the efficacy of these tools can be improved.

  19. Parallel Earthquake Simulations on Large-Scale Multicore Supercomputers

    KAUST Repository

    Wu, Xingfu


    Earthquakes are one of the most destructive natural hazards on our planet Earth. Hugh earthquakes striking offshore may cause devastating tsunamis, as evidenced by the 11 March 2011 Japan (moment magnitude Mw9.0) and the 26 December 2004 Sumatra (Mw9.1) earthquakes. Earthquake prediction (in terms of the precise time, place, and magnitude of a coming earthquake) is arguably unfeasible in the foreseeable future. To mitigate seismic hazards from future earthquakes in earthquake-prone areas, such as California and Japan, scientists have been using numerical simulations to study earthquake rupture propagation along faults and seismic wave propagation in the surrounding media on ever-advancing modern computers over past several decades. In particular, ground motion simulations for past and future (possible) significant earthquakes have been performed to understand factors that affect ground shaking in populated areas, and to provide ground shaking characteristics and synthetic seismograms for emergency preparation and design of earthquake-resistant structures. These simulation results can guide the development of more rational seismic provisions for leading to safer, more efficient, and economical50pt]Please provide V. Taylor author e-mail ID. structures in earthquake-prone regions.

  20. Uncovering the 2010 Haiti earthquake death toll (United States)

    Daniell, J. E.; Khazai, B.; Wenzel, F.


    Casualties are estimated for the 12 January 2010 earthquake in Haiti using various reports calibrated by observed building damage states from satellite imagery and reconnaissance reports on the ground. By investigating various damage reports, casualty estimates and burial figures, for a one year period from 12 January 2010 until 12 January 2011, there is also strong evidence that the official government figures of 316 000 total dead and missing, reported to have been caused by the earthquake, are significantly overestimated. The authors have examined damage and casualties report to arrive at their estimation that the median death toll is less than half of this value (±137 000). The authors show through a study of historical earthquake death tolls, that overestimates of earthquake death tolls occur in many cases, and is not unique to Haiti. As death toll is one of the key elements for determining the amount of aid and reconstruction funds that will be mobilized, scientific means to estimate death tolls should be applied. Studies of international aid in recent natural disasters reveal that large distributions of aid which do not match the respective needs may cause oversupply of help, aggravate corruption and social disruption rather than reduce them, and lead to distrust within the donor community.

  1. The 2010 Canterbury Earthquake: Curriculum Shockwaves (United States)

    Taylor, Mike; Moeed, Azra


    This paper reports data from an exploratory questionnaire designed to capture "curriculum P-waves"--those curriculum responses that were the fastest and therefore measured first--following a significant earthquake in New Zealand. As well as taking a professional interest in a major disaster in their backyard, it is assumed that social…


    DEFF Research Database (Denmark)

    Zania, Varvara; Tsompanakis, Yiannis; Psarropoulos, Prodromos

    importance, the current study examines the impact of both types of earthquake hazards by performing efficient finite-element analyses. These took also into account the potential slip displacement development along the geosynthetic interfaces of the composite base liner. At first, the development of permanent...

  3. Earthquake, strong tide and global low temperature

    Institute of Scientific and Technical Information of China (English)


    "La Madre" is a kind of upper atmospheric air current, and occurs as "warm phase" and "cold phase" in the sky of Pacific Ocean alternately. There exists this phenomenon, called "Oscillation Decade in the Pacific" (ODP), for 20~30years. It is concerned with 60 year cycle of the tides. Lunar oscillations explain an intriguing 60-year cycle in the world's temperature. Strong tides increase the vertical mixing of water in the oceans, drawing cold ocean water from the depths to surface, where it cools the atmosphere above. The first strong seismic episode in China was from 1897 to 1912; the second to the fifth was the in1920-1937, 1946-1957, 1966-1980, 1991-2002, tsrectruely. The alternative boundaries of"La Madre" warm phase and cold phase were in 1890, 1924, 1946 and 2000, which were near the boundaries of four strong earthquakes. It indicated the strong earthquakes closedly related with the substances' motion of atmosphere, hydrosphere and lithosphere, the change of gravity potential, and the exchange of angular momentum. The strong earthquakes in the ocean bottom can bring the cool waters at the deep ocean up to the ocean surface and make the global climate cold. the earthquake, strong tide and global low temperature are close inrelntion for each othen.

  4. Earthquake Damage, Armenian SSR, December 7, 1988 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — On December 7, 1988, at 11:41 A.M. local time a magnitude 6.9 earthquake shook northwestern Armenia and was followed four minutes later by a magnitude 5.8...

  5. Google Mapplets for Earthquakes and Volcanic Activity (United States)

    Haefner, S. A.; Venezky, D. Y.


    The USGS Earthquake and Volcano Hazards Programs monitor, assess, and issue warnings of natural hazards. Users can access our hazards information through our web pages, RSS feeds, and now through USGS Mapplets. Mapplets allow third party data layers to be added on top of Google Maps ( - My Maps tab). Mapplets are created by parsing a GeoRSS feed, which involves searching through an XML file for location data and plotting the associated information on a map. The new Mapplets allow users to view both real-time earthquakes and current volcanic activity on the same map for the first time. In addition, the USGS Mapplets have been added to Google's extensive collection of Mapplets, allowing users to add the types of information they want to see on their own customized maps. The Earthquake Mapplet plots the past week of earthquakes around the world, showing the location, time and magnitude. The Volcano Mapplet displays the latest U.S. volcano updates, including the current level of both ground-based and aviation hazards. Join us to discuss how Mapplets are made and how they can be used to create your own customized map.

  6. Estimation of Natural Frequencies During Earthquakes

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Rytter, A


    This paper presents two different recursive prediction error method (RPEM} implementations of multivariate Auto-Regressive Moving- Average (ARMAV) models for identification of a time variant civil engineering structure subject to an earthquake. The two techniques are tested on measurements made...

  7. Fifth Grade Elementary Students' Conceptions of Earthquakes (United States)

    Savasci, Funda; Uluduz, Hatice


    This study intends to investigate the fifth grade students' conceptions of earthquakes. Twenty two grade 5 students (11-12 years old) from five different elementary schools in Istanbul voluntarily participated in the study. Data were collected from semi-structured interviews with each participant. Six interview questions were designed by…

  8. The Development of an Earthquake Mind Mapping

    Directory of Open Access Journals (Sweden)

    Sri Adelila Sari


    Full Text Available The students were difficult to understand about earthquake caused the teaching methods used by teachers were still using the classic method. The teachers only used a textbook to teach the students without any other supporting equipments. Learning process by using the discourse method makes students thinking monotonically, so that only concentrated on the students' understanding of the matter presented by the teacher. Therefore, this study was aimed to develop an earthquake mind mapping to help students in the process of remembering and recording the material being taught by the teacher. The type of this study was Research and Development (R & D. Data were analyzed using descriptive statistics. The samples in this study were class of I-3Madrasah Tsanawiyah (MTs Darul Ulum Banda Aceh totaling 30 students. The results showed that mind mapping was developed by 5 stages in ADDIE models: analysis (analyzing the problem and find a solution, design (determine the learning strategies, development (producing an earthquake mind mapping to be used in the learning process, implementation (implementing learning activities using the media and evaluation (evaluating the learning activities. When students instructed to create their mind mapping, it was found that the products of mind mapping categorized in skilled and quite skilled were amounted to 73.33 and 26.66% respectively. As recommendation an earthquake mind mapping could be applied and useful as an effective learning.

  9. International Handbook of Earthquake and Engineering Seismology

    Institute of Scientific and Technical Information of China (English)

    陈运泰; 吴忠良


    @@ To celebrate the 100 Anniversary of the International Association of Seismology (now International Association of Seismology and Physics of the Earth's Interior, IASPEI), the International Handbook of Earthquake and Engineering Seismology, Volumes 1 and 2, were published by Academic Press in 2002 and 2003, respectively.

  10. Simulations of the 1906 San Francisco Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A; Petersson, A; Tkalcic, H


    Simulations of the Great 1906 San Francisco earthquake are being performed as part of the event's centenary. LLNL is participating in a large effort to study this event and possible consequences if the event were to happen today. This document is meant to describe our efforts to others participating in the project.

  11. Discrete Conformal Approximation of Complex Earthquake Maps (United States)


    sur les Surfaces [The Works of Thurston on Surfaces]." Asterisque, Sdminaire Orsay, Volume 66-67, Socidt6 Mathematique de France, Paris, 1979. [22...Brock Williams. "Earthquakes and Circle Packing." Journal D’Analyse Mathematique , Volume 85, 2001, pp. 371-396. [55] Stephen Wolfram. The Mathematica

  12. Prediction of slope failure due to earthquake

    Institute of Scientific and Technical Information of China (English)

    CHEN XiaoLi; KATO Nobuaki; TSUNAKI Ryosuke; MUKAI Keiji


    The earthquake-triggered landslides and slope failures are common phenomena during strong earthquakes and have drawn more attention from the world because of severe hazards they induced.These hazards usually cannot be prevented by current mitigating measures,thus,it becomes more and more important to develop a precise technique for the risk assessment of earthquake-induced failures in the mountainous area.The application of discrimination analysis method is proved to be successful and effective in the prediction of earthquake-triggered landslides and slope failures in the region of Imokawa Basin in Japan.Diacriminant score can be used to assess the relative risk of slope failures,as the score increases,the possibility of slope failures occurrence increases accordingly.At the same time,the variables in the judgement formula,such as slope gradient,slope curvature and seismic peak ground acceleration,are easy to obtain.This advantage makes this method more practical and manipulable than others at present.In order to apply this method more effectively,there are still several problems to resolve.

  13. The 2010 Canterbury Earthquake: Curriculum Shockwaves (United States)

    Taylor, Mike; Moeed, Azra


    This paper reports data from an exploratory questionnaire designed to capture "curriculum P-waves"--those curriculum responses that were the fastest and therefore measured first--following a significant earthquake in New Zealand. As well as taking a professional interest in a major disaster in their backyard, it is assumed that social science and…

  14. Chest injury in victims of Bam earthquake

    Institute of Scientific and Technical Information of China (English)

    Seyed Mohammad Ghodsi; Moosa Zargar; Ali Khaji; Mojgan Karbakhsh


    Objective: To analyze the data of trauma patients with thoracic injury in the earthquake of Bam admitted to hospitals of Tehran University of Medical Science (TUMS)for better understanding the type and consequence of thoracic injuries in a major earthquake.Methods: After Bam earthquake registering 6.5 on the Richter scale, 526 trauma patients were admitted to hospitals of TUMS. Among them, 53 patients sustained thoracic injury.Results: This group was composed of 21 females (39.6%) and 32 males (60.4%). Fifteen patients (28.3%) had isolated chest injuries. Rib fracture (36.4%) was the most common injury in our patients and haemo/pneumothorax (25.5%) followed. Superficial injury was the most common accompanying injury. Multipletrauma patients with chest injury had higher injury severity score (ISS) versus patients with isolated chest injury (P =0.003).Conclusions: Chest wall injuries and haemo/pneumothorax comprise a considerable number of injuries in survival victims of earthquakes. Consequently, the majority of these patients can be treated with observation or tube thoracostomy. We should train and equip the health workers and members of rescue teams to treat and manage these patients in the field.

  15. Responses to the 2011 Earthquake on Facebook

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    In my investigation of how Japanese ODA policies and practices have engendered global networks, I have frequented the Association of Overseas Technical Scholarships (AOTS)' Facebook group. In the wake of the earthquake on March 11, 2011, many greetings came in from alumni who have within the last...

  16. Adolescent earthquake survivors' show increased prefrontal cortex activation to masked earthquake images as adults. (United States)

    Du, Xue; Wei, Dongtao; Ganzel, Barbara L; Kim, Pilyoung; Zhang, Qinglin; Qiu, Jiang


    The great Sichuan earthquake in China on May 12, 2008 was a traumatic event to many who live near the earthquake area. However, at present, there are few studies that explore the long-term impact of the adolescent trauma exposure on adults' brain function. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate the brain activation evoked by masked trauma-related stimuli (earthquake versus neutral images) in 14 adults who lived near the epicenter of the great Sichuan earthquake when they were adolescents (trauma-exposed group) and 14 adults who lived farther from the epicenter of the earthquake when they were adolescents (control group). Compared with the control group, the trauma-exposed group showed significant elevation of activation in the right anterior cingulate cortex (ACC) and the medial prefrontal cortex (MPFC) in response to masked earthquake-related images. In the trauma-exposed group, the right ACC activation was negatively correlated with the frequency of symptoms of post-traumatic stress disorder (PTSD). These findings differ markedly from the long-term effects of trauma exposure in adults. This suggests that trauma exposure during adolescence may have a unique long-term impact on ACC/MPFC function, top-down modulation of trauma-related information, and subsequent symptoms of PTSD.

  17. The USGS Earthquake Notification Service (ENS): Customizable notifications of earthquakes around the globe (United States)

    Wald, Lisa A.; Wald, David J.; Schwarz, Stan; Presgrave, Bruce; Earle, Paul S.; Martinez, Eric; Oppenheimer, David


    At the beginning of 2006, the U.S. Geological Survey (USGS) Earthquake Hazards Program (EHP) introduced a new automated Earthquake Notification Service (ENS) to take the place of the National Earthquake Information Center (NEIC) "Bigquake" system and the various other individual EHP e-mail list-servers for separate regions in the United States. These included northern California, southern California, and the central and eastern United States. ENS is a "one-stop shopping" system that allows Internet users to subscribe to flexible and customizable notifications for earthquakes anywhere in the world. The customization capability allows users to define the what (magnitude threshold), the when (day and night thresholds), and the where (specific regions) for their notifications. Customization is achieved by employing a per-user based request profile, allowing the notifications to be tailored for each individual's requirements. Such earthquake-parameter-specific custom delivery was not possible with simple e-mail list-servers. Now that event and user profiles are in a structured query language (SQL) database, additional flexibility is possible. At the time of this writing, ENS had more than 114,000 subscribers, with more than 200,000 separate user profiles. On a typical day, more than 188,000 messages get sent to a variety of widely distributed users for a wide range of earthquake locations and magnitudes. The purpose of this article is to describe how ENS works, highlight the features it offers, and summarize plans for future developments.

  18. A Decade of Giant Earthquakes - What does it mean?

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Terry C. Jr. [Los Alamos National Laboratory


    On December 26, 2004 the largest earthquake since 1964 occurred near Ache, Indonesia. The magnitude 9.2 earthquake and subsequent tsunami killed a quarter of million people; it also marked the being of a period of extraordinary seismicity. Since the Ache earthquake there have been 16 magnitude 8 earthquakes globally, including 2 this last April. For the 100 years previous to 2004 there was an average of 1 magnitude 8 earthquake every 2.2 years; since 2004 there has been 2 per year. Since magnitude 8 earthquakes dominate global seismic energy release, this period of seismicity has seismologist rethinking what they understand about plate tectonics and the connectivity between giant earthquakes. This talk will explore this remarkable period of time and its possible implications.

  19. Modeling fast and slow earthquakes at various scales. (United States)

    Ide, Satoshi


    Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.

  20. The aftershock processes of strong earthquakes in the Western Caucasus (United States)

    Baranov, S. V.; Gabsatarova, I. P.


    The aftershock processes of the four strong earthquakes that occurred in the Western Caucasus from 1991 to June 2013 are considered. The main shocks of these earthquakes include the first Racha earthquake (April 29, 1991, Ms = 6.9); second Racha earthquake (June 15, 1991, Ms = 6.2); Oni earthquake (September 7, 2009, Ms = 5.8); and East Black Sea earthquake (December 23, 2012, Ms = 5.6). Based on the simulations with the LPL relaxation model and the ETAS model of triggered seismicity, the differences in the properties of the aftershock processes and the characteristics of the fault zones accommodating the main shocks are revealed. The nonrelaxation character of the aftershocks from the East Black Sea earthquake is established. It is hypothesized and validated that this is a result of the violation of the fluid-dynamic equilibrium in the fault zone due to the destruction of the gas hydrate layer by the main shock and strong aftershocks.

  1. Study on financial loss and its adjustment in earthquake insurance

    Institute of Scientific and Technical Information of China (English)

    LIU Ru-shan; WANG Zifa; ZHU Min


    In the paper, we briefly introduce the development and present situation of earthquake insurance in China and foreign countries, and the evaluation of earthquake losses on the basis of seismic risk and structural vulnerability analyses. The emphasis is given to the probabilistic density function of earthquake loss adjustment for a single building under the given insurance policy and the overall variance of estimated earthquake losses aggregated from various locations with keen interest in the insurance industries. The correlation coefficient for the damages among single structures in the United States is also introduced to interpret the risk of loss concentration in the earthquake insurance. The paper provides a scientific basis for adjusting earthquake loss and premium rate, and it also provides a useful reference for the application and expansion of earthquake insurance in China.

  2. Public participation in reconstruction after the earthquakes in Friuli (Italy) and the Upper Soca Valley (Slovenia) in 1976, 1998, and 2004 (United States)

    Pipan, P.


    Northern Friuli (in northeast Italy) and the Upper Soča Valley (in northwest Slovenia) are extremely seismically active. The earthquakes of 6 May and 15 September 1976, with an epicenter in the Venzone area, claimed 939 lives in Italy and 157,000 people were left homeless. The same two earthquakes affected northwest Slovenia, which was still part of communist Yugoslavia at the time; they did not claim any lives, but they damaged 12,000 buildings and 13,000 people were left homeless. The "Easter Earthquake" of 12 April 1998, with an epicenter in the Krn Mountains, damaged 4,000 structures in Slovenia, among which nearly 1,500 had to be completely rebuilt. Even though there was noticeably less damage than in the 1976 earthquakes, in some settlements more than 80% of the houses were damaged. The same area was hit by another earthquake on 12 July 2004, which damaged nearly 2,000 structures, including some that had already been repaired after the 1998 earthquake. More than three decades after the 1976 earthquakes, a qualitative study was carried out on public participation in rebuilding after these earthquakes and public influence on the success of rebuilding. The research is based on studies of cases of individual settlements in Italy and Slovenia, where in-depth interviews were conducted with relevant persons that had been directly involved in the post-earthquake rebuilding efforts. This article highlights six case studies ranked on Arnstein's ladder of citizen participation. Examples from Italy include Venzone, Portis, and Resia for the 1976 earthquakes, and examples from Slovenia include Breginj for the 1976 earthquakes, Drežni\\vske Ravne for the 1998 earthquake, and Čezsoča for the 1998 and 2004 earthquakes. Alongside various political, legislative, and administrative circumstances, a responsible citizenry was also an important factor. In the case of Venzone, the majority of the residents and stakeholders had a positive influence on the preservation of

  3. On the nature of intraplate earthquakes (United States)

    Talwani, Pradeep


    Continental intraplate regions are characterized by uniform stresses over thousands of kilometers. Local stresses, with wavelengths of tens to hundreds of kilometers can accumulate at inhomogeneities lying within these regional fields. A variety of geological structures, herein called local stress concentrators (LSCs), act as elastic inhomogeneities. The temporal buildup of stress depends on the particular structure and its geometrical relationship with the regional stress field. The interaction of the local and the regional stress fields can result in the rotation of the latter over wavelengths of tens to hundreds of kilometers. This rotation can be detected by direct measurement or from seismicity data. Intraplate earthquakes (IPEs) result when the local stresses become comparable with their regional counterparts, i.e., hundreds of megapascals. Globally, most of the seismic energy release associated with IPEs occurs within old rifts which contain LSCs most favorable for stress buildup by stress inversion. Of the various LSCs, stepover en echelon faults are associated the largest IPEs. In low tectonic strain rate regions, IPEs are associated with larger stress drops. With the availability of a variety of LSCs, there is generally an absence of repeat earthquakes. Instead, successive earthquakes occur on different structures, leading to the observation of "roaming" earthquakes. These observations suggest a need for a reevaluation of seismic hazard estimation techniques. This study addresses some of these facets of the nature of IPEs with global examples, including a unique, detailed seismicity and geodetic data set collected in a dozen years following the 2001 M 7.7 Bhuj earthquake in western India.

  4. Earthquake dynamics. Supershear rupture in a M(w) 6.7 aftershock of the 2013 Sea of Okhotsk earthquake. (United States)

    Zhan, Zhongwen; Helmberger, Donald V; Kanamori, Hiroo; Shearer, Peter M


    Earthquake rupture speeds exceeding the shear-wave velocity have been reported for several shallow strike-slip events. Whether supershear rupture also can occur in deep earthquakes is unclear, because of their enigmatic faulting mechanism. Using empirical Green's functions in both regional and teleseismic waveforms, we observed supershear rupture during the 2013 moment magnitude (M(w)) 6.7 deep earthquake beneath the Sea of Okhotsk, an aftershock of the large deep earthquake (M(w) 8.3). The M(w) 6.7 event ruptured downward along a steeply dipping fault plane at an average speed of 8 kilometers per second, suggesting efficient seismic energy generation. Comparing it to the highly dissipative 1994 M(w) 8.3 Bolivia earthquake, the two events represent end members of deep earthquakes in terms of energy partitioning and imply that there is more than one rupture mechanism for deep earthquakes.

  5. The interannual earthquake distributions and its peculiarity. (United States)

    Levin, Boris; Sasorova, Elena


    The study of the periodicity of seismic process activation at different energy levels represents a topical problem in seismology, and it might help to illuminate the physical mechanisms that govern the processes of preparation and generation of earthquakes. It was observed during written history, that the seismic events occur in various regions of the Earth in some months of a year significantly more often than in another. In the last decade, there has been growing interest in problems related to searching for global spatiotemporal regularities in the distribution of seismic events on the Earth. The objective of our work is to test of hypothesis about within-year variability existence for the events of various energy levels, to determine the lithosphere depth boundary which divided the seismic events on two groups (subjected to external (tidal) forces and no subjected to these forces) and to search the global regularity in spatio-temporal distributions of the seismic events in the Pacific. The whole region was subdivided into 31 subregions, which are located along the perimeter of the Pacific. All events in each subregion were subdivided into five subsets according to following magnitude levels: 4 Htr), where H is the hypocenter depth and Htr is the threshold value of the EQ source depth. For the first time Htr was set equal to 80 km. Then we were checking if the distributions of the events during the year period are uniform or these distributions are non-uniform. Our data sets are binned data. We obtained simultaneously two discrete time scale (monthly and 10-days). We are testing it separately for each region, for each magnitude level and for every depth level. The null hypothesis about uniform EQ distributions in the course of year was disproved for the most samples with "shallow" EQ. But the null hypothesis was confirmed for "deep" earthquakes. We use the Chi-Square test for well-filled sequences (no less than 5 events in each discrete interval) and the method

  6. Preliminary study on variation characteristics of ocean tide dynamic stress in crust and its relationship with earthquakes

    Institute of Scientific and Technical Information of China (English)

    LU Ming-yong; ZHENG Wen-heng


    The variation characteristics of dynamic stress in crustal blocks and its relationship with earthquakes are comprehensively studied by analyzing geophysical data and calculating the dynamic response of crustal blocks in North China to the tide level change of Bohai Sea and Yellow Sea using a 3D nonlinear dynamic finite element simulation. This study has noticed some new features of crustal dynamic stress: (a) High stress level appears at the place where the stress waves superpose and interference during the process of propagation, and the enhancement of dynamic shear stress is more significant as compared with that of compressive stress; (b) Variation of dynamic stress has influence on seismogenic environment and hence earthquake occurrence; (c) As viewed from the variation characteristics of crustal dynamic stress, the superimposing process of shear stress manifests the preparation process of earthquakes.

  7. Investigation of the ability for slow slip events to trigger earthquakes through a comparison of seismic and geodetic observations with fault slip simulations (United States)

    Colella, H.; Brudzinski, M. R.; Richards-Dinger, K. B.


    There is growing evidence that slow slip events (SSEs) promote nearby seismicity, often in the form of swarms of small to moderate earthquakes or as tectonic tremor that are primarily swarms of low frequency earthquakes. Yet the question remains whether SSEs are capable of triggering large to great earthquakes due to the generally small stress change associated with typical SSEs. There have been a few recent large to great earthquakes that appear to have been preceded by evidence of a SSE, but whether these cases are rare is not yet clear. Even if several other cases were documented, it would still be difficult to translate this information into quantitative estimates of the hazard increase during a given SSE. In this study, we move towards this long-term goal with an earthquake simulator (RSQSim), which is capable of modeling a variety of fault slip behaviors (i.e. earthquakes, SSEs, and continuous creep), and can generate robust statistics on the relationships between SSEs, microseismicity, and large/great earthquakes. The simulations seek to explain observations like those of the recent Mw 7.4 Ometepec, Mexico and Mw 6.5 Cook Strait earthquakes that show increased seismic activity in small fault patches between the transition zone and mainshock source zone during SSEs that were in process in the months leading up to, and particularly immediately prior to, the mainshock. The potential causative relationships will be probed with models that use a range of fault properties and configurations. One hypothesis to test is whether observed swarms of seismicity during SSEs represent fast slip on weaker areas of the plate interface that are more sensitive to the relatively small stress changes associated with SSEs. An alternative hypothesis is that no area of the fault is more easily influenced by SSEs, just that the relative prevalence of smaller earthquakes leads to more frequent observations of the triggered mainshocks.

  8. Relocation of the 1998 Zhangbei-Shangyi earthquake sequence using the double difference earthquake location algorithm

    Institute of Scientific and Technical Information of China (English)

    杨智娴; 陈运泰


    On January 10, 1998, at 11h50min Beijing Time (03h50min UTC), an earthquake of ML=6.2 occurred in the border region between the Zhangbei County and Shangyi County of Hebei Province. This earthquake is the most significant event to have occurred in northern China in the recent years. The earthquake-generating structure of this event was not clear due to no active fault capable of generating a moderate earthquake was found in the epicentral area,nor surface ruptures with any predominate orientation were observed, no distinct orientation of its aftershock distribution given by routine earthquake location was shown. To study the seismogenic structure of the ZhangbeiShangyi earthquake, the main shock and its aftershocks with ML≥3.0 of the Zhangbei-Shangyi earthquake sequence were relocated by the authors of this paper in 2002 using the master event relative relocation technique.The relocated epicenter of the main shock was located at 41.145°N, 114.462°E, which was located 4 km to the NE of the macro-epicenter of this event. The relocated focal depth of the main shock was 15 km. Hypocenters of the aftershocks distributed in a nearly vertical plane striking 180°~200° and its vicinity. The relocated results of the Zhangbei-Shangyi earthquake sequence clearly indicated that the seismogenic structure of this event was a NNE-SSW-striking fault with right-lateral and reverse slip. In this paper, a relocation of the Zhangbei-Shangyi earthquake sequence has been done using the double difference earthquake location algorithm (DD algorithm), and consistent results with that obtained by the master event technique were obtained. The relocated hypocenters of the main shock are located at 41.131 °N, 114.456°E, which was located 2.5 km to the NE of the macro-epicenter of the main shock. The relocated focal depth of the main shock was 12.8 km. Hypocenters of the aftershocks also distributed in a nearly vertical N10°E-striking plane and its vicinity. The relocated results

  9. Seismic displacement of gently-sloping coastal and marine sediment under multidirectional earthquake loading (United States)

    Kayen, Robert


    Gentle sediment-laden slopes are typical of the onshore coastal zone and offshore continental shelf and slope. Coastal sediment are commonly young weakly consolidated materials that are well stratified, have low strength, and can mobilize shear displacements at low levels of stress. Seismically-driven plastic displacements of these sediment pose a hazard to coastal cities, buried onshore utilities, and offshore infrastructure like harbor protection and outfalls. One-dimensional rigid downslope-directed Newmark sliding block analyses have been used to predict earthquake deformations generally on steeper slopes that are modeled as frictional materials. This study probes the effect of multidirectional earthquake motions on inertial displacements of gently sloping ground of the coastal and offshore condition where soft-compliant soil is expected. Toward that objective, this investigation seeks to understand the effect on Newmark-type displacements of [1] multidirectional earthquake shaking and [2] soil compliance. In order to model multidirectional effects, the earthquake motions are rotated into the local slope strike- and dip-components. On gently sloping ground, including the strike component of motion always results in a larger and more accurate shear stress vector. Strike motions are found to contribute to downslope deformations on any declivity. Compliant response of the soil mass also influences the plastic displacements. The magnitude of seismic displacements can be estimated with a simplified model using only the estimated soil yield-acceleration (ky) and the peak ground velocity (Vmax) of the earthquake motions. Compliance effects can be effectively mapped using the concept of Plastic Displacement Response Spectra (PDRS).

  10. Monitoring Geologic Hazards and Vegetation Recovery in the Wenchuan Earthquake Region Using Aerial Photography

    Directory of Open Access Journals (Sweden)

    Zhenwang Li


    Full Text Available On 12 May 2008, the 8.0-magnitude Wenchuan earthquake occurred in Sichuan Province, China, triggering thousands of landslides, debris flows, and barrier lakes, leading to a substantial loss of life and damage to the local environment and infrastructure. This study aimed to monitor the status of geologic hazards and vegetation recovery in a post-earthquake disaster area using high-resolution aerial photography from 2008 to 2011, acquired from the Center for Earth Observation and Digital Earth (CEODE, Chinese Academy of Sciences. The distribution and range of hazards were identified in 15 large, representative geologic hazard areas triggered by the Wenchuan earthquake. After conducting an overlay analysis, the variations of these hazards between successive years were analyzed to reflect the geologic hazard development and vegetation recovery. The results showed that in the first year after the Wenchuan earthquake, debris flows occurred frequently with high intensity. Resultantly, with the source material becoming less available and the slope structure stabilizing, the intensity and frequency of debris flows gradually decreased with time. The development rate of debris flows between 2008 and 2011 was 3% per year. The lithology played a dominant role in the formation of debris flows, and the topography and hazard size in the earthquake affected area also had an influence on the debris flow development process. Meanwhile, the overall geologic hazard area decreased at 12% per year, and the vegetation recovery on the landslide mass was 15% to 20% per year between 2008 and 2011. The outcomes of this study provide supporting data for ecological recovery as well as debris flow control and prevention projects in hazard-prone areas.

  11. Earthquake Hazard Mitigation Using a Systems Analysis Approach to Risk Assessment (United States)

    Legg, M.; Eguchi, R. T.


    The earthquake hazard mitigation goal is to reduce losses due to severe natural events. The first step is to conduct a Seismic Risk Assessment consisting of 1) hazard estimation, 2) vulnerability analysis, 3) exposure compilation. Seismic hazards include ground deformation, shaking, and inundation. The hazard estimation may be probabilistic or deterministic. Probabilistic Seismic Hazard Assessment (PSHA) is generally applied to site-specific Risk assessments, but may involve large areas as in a National Seismic Hazard Mapping program. Deterministic hazard assessments are needed for geographically distributed exposure such as lifelines (infrastructure), but may be important for large communities. Vulnerability evaluation includes quantification of fragility for construction or components including personnel. Exposure represents the existing or planned construction, facilities, infrastructure, and population in the affected area. Risk (expected loss) is the product of the quantified hazard, vulnerability (damage algorithm), and exposure which may be used to prepare emergency response plans, retrofit existing construction, or use community planning to avoid hazards. The risk estimate provides data needed to acquire earthquake insurance to assist with effective recovery following a severe event. Earthquake Scenarios used in Deterministic Risk Assessments provide detailed information on where hazards may be most severe, what system components are most susceptible to failure, and to evaluate the combined effects of a severe earthquake to the whole system or community. Casualties (injuries and death) have been the primary factor in defining building codes for seismic-resistant construction. Economic losses may be equally significant factors that can influence proactive hazard mitigation. Large urban earthquakes may produce catastrophic losses due to a cascading of effects often missed in PSHA. Economic collapse may ensue if damaged workplaces, disruption of utilities, and

  12. Electric field and ion density anomalies in the mid latitude ionosphere: Possible connection with earthquakes? (United States)

    Gousheva, M. N.; Glavcheva, R. P.; Danov, D. L.; Hristov, P. L.; Kirov, B. B.; Georgieva, K. Y.


    The problem of earthquake prediction has stimulated the search for a correlation between seismic activity and ionospherical anomalies. We found observational evidence of possible earthquake effects in the near-equatorial and low latitude ionosphere; these ionospheric anomalies have been proposed by Gousheva et al. [Gousheva, M., Glavcheva, R., Danov, D., Angelov P., Hristov, P., Influence of earthquakes on the electric field disturbances in the ionosphere on board of the Intercosmos-Bulgaria-1300 satellite. Compt. Rend. Acad. Bulg. Sci. 58 (8) 911-916, 2005a; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Observation from the Intercosmos-Bulgaria-1300 satellite of anomalies associated with seismic activity. In: Poster Proceeding of 2nd International Conference on Recent Advances in Space Technologies: Space in the Service of Society, RAST '2005, June 9-11, Istanbul, Turkey, pp. 119-123, 2005b; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Satellite monitoring of anomalous effects in the ionosphere probably related to strong earthquakes. Adv. Space Res. 37 (4), 660-665, 2006]. This paper presents new results from observations of the quasi-static electric field and ion density on board INTERCOSMOS-BULGARIA-1300 satellite in the mid latitude ionosphere above sources of moderate earthquakes. Data from INTERCOSMOS-BULGARIA-1300 satellite and seismic data (World Data Center, Denver, Colorado, USA) for magnetically quiet and medium quiet days are juxtaposed in time-space domain. For satellite's orbits in the time period 15.09-01.10.1981 an increase in the horizontal and vertical components of the quasi-static electric field and fluctuations of the ion density are observed over zones of forthcoming seismic events. Some similar post effects are observed too. The emphasis of this paper is put on the anomalies which specify the mid latitude ionosphere. The obtained results contain

  13. A possible scenario for earlier occurrence of the next Nankai earthquake due to triggering by an earthquake at Hyuga-nada, off southwest Japan (United States)

    Hyodo, Mamoru; Hori, Takane; Kaneda, Yoshiyuki


    Several recent large-scale earthquakes including the 2011 Tohoku earthquake ( M w 9.0) in northeastern Japan and the 2014 Iquique earthquake ( M w 8.1) in northern Chile were associated with foreshock activities ( M w > 6). The detailed mechanisms between these large earthquakes and the preceding smaller earthquakes are still unknown; however, to plan for disaster mitigation against the anticipated great Nankai Trough earthquakes, in this study, possible scenarios after M w 7-class earthquakes that frequently occur near the focal region of the Nankai Trough are examined through quasi-dynamic modeling of seismic cycles. By assuming that simulated Nankai Trough earthquakes recur as two alternative earthquakes with variations in magnitudes ( M w 8.7-8.4) and recurrence intervals (178-143 years), we systematically examine the effect of the occurrence timing of the M w 7 Hyuga-nada earthquake on the western extension of the source region of Nankai Trough earthquakes on the assumed Nankai Trough seismic cycles. We find that in the latter half of a seismic cycle preceding a large Nankai Trough earthquake, an immature Nankai earthquake tends to be triggered within several years after the occurrence of a Hyuga-nada earthquake, then Tokai (Tonankai) earthquakes occur with maximum time lags of several years. The combined magnitudes of the triggered Nankai and subsequent Tokai (Tonankai) earthquakes become gradually larger with later occurrence of the Hyuga-nada earthquake, while the rupture timings between the Nankai and Tokai (Tonankai) earthquakes become smaller. The triggered occurrence of an immature Nankai Trough earthquake could delay the expected larger Nankai Trough earthquake to the next seismic cycle. Our results indicate that triggering can explain the variety and complexity of historical Nankai Trough earthquakes. Moreover, for the next anticipated event, countermeasures should include the possibility of a triggered occurrence of a Nankai Trough earthquake by an M

  14. Statistical validation of earthquake related observations (United States)

    Kossobokov, V. G.


    The confirmed fractal nature of earthquakes and their distribution in space and time implies that many traditional estimations of seismic hazard (from term-less to short-term ones) are usually based on erroneous assumptions of easy tractable or, conversely, delicately-designed models. The widespread practice of deceptive modeling considered as a "reasonable proxy" of the natural seismic process leads to seismic hazard assessment of unknown quality, which errors propagate non-linearly into inflicted estimates of risk and, eventually, into unexpected societal losses of unacceptable level. The studies aimed at forecast/prediction of earthquakes must include validation in the retro- (at least) and, eventually, in prospective tests. In the absence of such control a suggested "precursor/signal" remains a "candidate", which link to target seismic event is a model assumption. Predicting in advance is the only decisive test of forecast/predictions and, therefore, the score-card of any "established precursor/signal" represented by the empirical probabilities of alarms and failures-to-predict achieved in prospective testing must prove statistical significance rejecting the null-hypothesis of random coincidental occurrence in advance target earthquakes. We reiterate suggesting so-called "Seismic Roulette" null-hypothesis as the most adequate undisturbed random alternative accounting for the empirical spatial distribution of earthquakes: (i) Consider a roulette wheel with as many sectors as the number of earthquake locations from a sample catalog representing seismic locus, a sector per each location and (ii) make your bet according to prediction (i.e., determine, which locations are inside area of alarm, and put one chip in each of the corresponding sectors); (iii) Nature turns the wheel; (iv) accumulate statistics of wins and losses along with the number of chips spent. If a precursor in charge of prediction exposes an imperfection of Seismic Roulette then, having in mind

  15. Prehistoric Earthquakes in the Puget Lowland, Washington (United States)

    Sherrod, B. L.


    Coastal marsh deposits and lidar topographic data show evidence for past earthquakes on at least seven fault zones in the Puget lowland. Three major fault zones, the Seattle fault zone, Tacoma fault, and the Southern Whidbey Island fault zone (SWIFZ), cut through the heavily populated portions of central Puget Sound. Faults in four other areas, namely the Darrington-Devils Mountain fault zone, Olympia fault, the northern margin of the Olympic Mountains, and the southeastern Olympic Mountains, show that the area of active Holocene faulting extends over the entire Puget Sound lowlands. As recently as 1998, field evidence could confirm only one fault with evidence of past earthquake activity. Uplifted coastlines and surface ruptures are the field evidence for past Seattle fault earthquakes. Raised intertidal platforms along the Seattle fault zone show that regional uplift of as much as 7 meters accompanied a large earthquake about 1100 years. This earthquake also caused a tsunami, which inundated low-lying coastal areas north of Seattle. All of the lidar scarps found in the Seattle fault zone are north-side-up, opposite the vergence suggested for the Seattle fault from regional geological studies. Excavations across these scarps reveal north-dipping thrust faults that roughly follow bedding planes in bedrock and disrupt late Holocene soils. Soil stratigraphy and radiocarbon ages suggest as many as three surface-rupturing earthquakes in the past 2500 years. Lidar mapping revealed several en echelon scarps along the trace of the Tacoma fault. Existence of the Tacoma fault was previously hypothesized on the basis of large-amplitude gravity, aeromagnetic, and seismic-velocity anomalies, shallow marine seismic reflection surveys, glaciolacustrine strandlines, and coastal marsh stratigraphy. Coastal marsh deposits and scarp excavations suggest that the scarps formed during an earthquake on the Tacoma fault ~1100 years ago, possibly by folding above a buried reverse fault

  16. Research in historical earthquakes in the Korean peninsula and its circumferential regions

    Institute of Scientific and Technical Information of China (English)

    翟文杰; 吴戈; 韩绍欣


    @@ The historical earthquake data is one of the important foundations for seismic monitoring, earthquake fore-cast and seismic safety evaluation. However, the recognition of earthquake is limited by the scientific and techno-logical level. Therefore, the earthquake can only be described using perfect earthquake catalogue after the seismo-graph is invented. Before this time, the earthquake parameters were determined according to the earthquake disas-ter on the surface and the written records in history, and the earthquake level was measured using earthquake in-tensity.

  17. Prediction of earthquake-triggered landslide event sizes (United States)

    Braun, Anika; Havenith, Hans-Balder; Schlögel, Romy


    Seismically induced landslides are a major environmental effect of earthquakes, which may significantly contribute to related losses. Moreover, in paleoseismology landslide event sizes are an important proxy for the estimation of the intensity and magnitude of past earthquakes and thus allowing us to improve seismic hazard assessment over longer terms. Not only earthquake intensity, but also factors such as the fault characteristics, topography, climatic conditions and the geological environment have a major impact on the intensity and spatial distribution of earthquake induced landslides. We present here a review of factors contributing to earthquake triggered slope failures based on an "event-by-event" classification approach. The objective of this analysis is to enable the short-term prediction of earthquake triggered landslide event sizes in terms of numbers and size of the affected area right after an earthquake event occurred. Five main factors, 'Intensity', 'Fault', 'Topographic energy', 'Climatic conditions' and 'Surface geology' were used to establish a relationship to the number and spatial extend of landslides triggered by an earthquake. The relative weight of these factors was extracted from published data for numerous past earthquakes; topographic inputs were checked in Google Earth and through geographic information systems. Based on well-documented recent earthquakes (e.g. Haiti 2010, Wenchuan 2008) and on older events for which reliable extensive information was available (e.g. Northridge 1994, Loma Prieta 1989, Guatemala 1976, Peru 1970) the combination and relative weight of the factors was calibrated. The calibrated factor combination was then applied to more than 20 earthquake events for which landslide distribution characteristics could be cross-checked. One of our main findings is that the 'Fault' factor, which is based on characteristics of the fault, the surface rupture and its location with respect to mountain areas, has the most important

  18. Rumours about the Po Valley earthquakes of 20th and 29th May 2012 (United States)

    La Longa, Federica; Crescimbene, Massimo; Camassi, Romano; Nostro, Concetta


    The history of rumours is as old as human history. Even in remote antiquity, rumours, gossip and hoax were always in circulation - in good or bad faith - to influence human affairs. Today with the development of mass media, rise of the internet and social networks, rumours are ubiquitous. The earthquakes, because of their characteristics of strong emotional impact and unpredictability, are among the natural events that more cause the birth and the spread of rumours. For this reason earthquakes that occurred in the Po valley the 20th and 29th May 2012 generated and still continue to generate a wide variety of rumours regarding issues related to the earthquake, its effects, the possible causes, future predictions. For this reason, as occurred during the L'Aquila earthquake sequence in 2009, following the events of May 2012 in Emilia Romagna was created a complex initiative training and information that at various stages between May and September 2012, involved population, partly present in the camp, and then the school staff of the municipalities affected by the earthquake. This experience has been organized and managed by the Department of Civil Protection (DPC), the National Institute of Geophysics and Volcanology (INGV), the Emilia Romagna region in collaboration with the Network of University Laboratories for Earthquake Engineering (RELUIS), the Health Service Emilia Romagna Regional and voluntary organizations of civil protection in the area. Within this initiative, in the period June-September 2012 were collected and catalogued over 240 rumours. In this work rumours of the Po Valley are studied in their specific characteristics and strategies and methods to fight them are also discussed. This work of collection and discussion of the rumours was particularly important to promote good communication strategies and to fight the spreading of the rumours. Only in this way it was possible to create a full intervention able to supporting both the local institutions and

  19. Impacts of earthquake on atoll in Nansha Islands, South China Sea (United States)

    Guo, Lei; Zhan, Wenhuan; Xiong, Lijia; Chen, Wujin; Yao, Yantao; Li, Jian


    Coral reef is a kind of rock soil masses. It is a special marine geotechnical medium, which are made up of the reef coral debris undergo very long geological age. Atoll is the predominant type of coral reefs in South China Sea. In recent years, there are more and more construction projects on the reef flat in Nansha Islands, South China Sea. Therefore, it is very important to estimate the stability of coral reefs, especially the atolls. According to the geological structure characters of atoll in Nansha Islands, a model of reef body is presented in this paper to study the influence of earthquake. Meanwhile, Geostudio, which is a popular geotechnical engineering simulation software, is used to stimulate the stress and deformation situation of reef body under different six kinds of earthquake intensity. The factor of safety can be calculated by the limit equilibrium method. And the possible scenario of earthquake-induced landslides and sliding scale can be defined through the Newmark sliding block method. The stress distribution and deformation behavior are studied. The main relations between atoll and earthquake are analyzed as follows: (1) the safety factor of reef slope exceeds 1.993 under self-gravity state; (2) It may cause slope's instability and bring slumping when the safety factor is less than one. The factor of safety decreases with increased earthquake intensity and it may fluctuate around a particular value when earthquake intensity continues to increase; (3) The smaller shallow landslide as new developed part of the reef is subject to collapse under earthquake action and the bigger slope of reef is more stable. The results show that it is feasible to evaluate the stability of coral reef by using geotechnical engineering simulation method, which can help to provide some information for construction on coral reefs in South China Sea. In the meantime,the authers wish to thank the National Natural Science Foundation of China (NO.41376063)and the National

  20. Magnitude and location of historical earthquakes in Japan and implications for the 1855 Ansei Edo earthquake (United States)

    Bakun, W.H.


    Japan Meteorological Agency (JMA) intensity assignments IJMA are used to derive intensity attenuation models suitable for estimating the location and an intensity magnitude Mjma for historical earthquakes in Japan. The intensity for shallow crustal earthquakes on Honshu is equal to -1.89 + 1.42MJMA - 0.00887?? h - 1.66log??h, where MJMA is the JMA magnitude, ??h = (??2 + h2)1/2, and ?? and h are epicentral distance and focal depth (km), respectively. Four earthquakes located near the Japan Trench were used to develop a subducting plate intensity attenuation model where intensity is equal to -8.33 + 2.19MJMA -0.00550??h - 1.14 log ?? h. The IJMA assignments for the MJMA7.9 great 1923 Kanto earthquake on the Philippine Sea-Eurasian plate interface are consistent with the subducting plate model; Using the subducting plate model and 226 IJMA IV-VI assignments, the location of the intensity center is 25 km north of the epicenter, Mjma is 7.7, and MJMA is 7.3-8.0 at the 1?? confidence level. Intensity assignments and reported aftershock activity for the enigmatic 11 November 1855 Ansei Edo earthquake are consistent with an MJMA 7.2 Philippine Sea-Eurasian interplate source or Philippine Sea intraslab source at about 30 km depth. If the 1855 earthquake was a Philippine Sea-Eurasian interplate event, the intensity center was adjacent to and downdip of the rupture area of the great 1923 Kanto earthquake, suggesting that the 1855 and 1923 events ruptured adjoining sections of the Philippine Sea-Eurasian plate interface.