Sample records for volcanic area requiring

  1. Volcanic hazard management in dispersed volcanism areas

    Marrero, Jose Manuel; Garcia, Alicia; Ortiz, Ramon


    Traditional volcanic hazard methodologies were developed mainly to deal with the big stratovolcanoes. In such type of volcanoes, the hazard map is an important tool for decision-makers not only during a volcanic crisis but also for territorial planning. According to the past and recent eruptions of a volcano, all possible volcanic hazards are modelled and included in the hazard map. Combining the hazard map with the Event Tree the impact area can be zoned and defining the likely eruptive scenarios that will be used during a real volcanic crisis. But in areas of disperse volcanism is very complex to apply the same volcanic hazard methodologies. The event tree do not take into account unknown vents, because the spatial concepts included in it are only related with the distance reached by volcanic hazards. The volcanic hazard simulation is also difficult because the vent scatter modifies the results. The volcanic susceptibility try to solve this problem, calculating the most likely areas to have an eruption, but the differences between low and large values obtained are often very small. In these conditions the traditional hazard map effectiveness could be questioned, making necessary a change in the concept of hazard map. Instead to delimit the potential impact areas, the hazard map should show the expected behaviour of the volcanic activity and how the differences in the landscape and internal geo-structures could condition such behaviour. This approach has been carried out in La Palma (Canary Islands), combining the concept of long-term hazard map with the short-term volcanic scenario to show the expected volcanic activity behaviour. The objective is the decision-makers understand how a volcanic crisis could be and what kind of mitigation measurement and strategy could be used.

  2. Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

    Langgeng Wahyu Santosa


    Full Text Available Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

  3. Geology and petrology of the Vulsinian volcanic area (Latium, Italy)

    Varekamp, J.C.


    The Vulsinian volcanic area is situated in Latium, west central Italy. This quarternary volcanic complex consists of a series of layered tuffs, lava flows, ignimbrites, and many small cinder and ash cones. A steep central edifice is lacking due to the relatively large amount of pyroclastic deposits.

  4. Self-potential anomalies in some Italian volcanic areas

    C. Silenziario


    Full Text Available The study of Self-Potential (SP space and time variations in volcanic areas may provide useful information on both the geometrical structure of the volcanic apparatuses and the dynamical behaviour of the feeding and uprising systems. In this paper, the results obtained on the islands of Vulcano (Eolian arc and Ponza (Pontine archipelago and on the Mt. Somma-Vesuvius complex are shown. On the island of Vulcano and on the Mt. Somma-Vesuvius apparatus areal SP surveys were performed with the aim of evidencing anomalies closely associated to the zones of major volcanic activity. On the island of Vulcano a profile across the fumaroles along the crater rim of the Fossa Cone was also carried out in order to have a direct relationship between fumarolic fracture migration and flow rate and SP anomaly space and time variations. The areal survey on the island of Ponza, which is considered an inactive area, is assumed as a reference test with which to compare the amplitude and pattern of the anomalies in the active areas. A tentative interpretation of the SP anomalies in volcanic areas is suggested in terms of electrokinetic phenomena, related to the movement of fluids of both volcanic and non-volcanic origin.

  5. Geodetic Monitoring System Operating On Neapolitan Volcanic Area (southern Italy)

    Pingue, F.; Ov-Geodesy Team

    The Neapolitan volcanic area is located in the southern sector of the Campanian Plain Graben including three volcanic active structures (Somma-Vesuvius, Campi Flegrei and Ischia). The Somma-Vesuvius complex, placed East of Naples, is a strato-volcano composed by a more ancient apparatus (Mt. Somma) and a younger cone (Mt. Vesu- vius) developed inside Somma caldera. Since last eruption (1944) it is in a quiescent state characterised by a low level seismicity and deformation activity. The Campi Fle- grei, located West of Naples, are a volcanic field inside an older caldera rim. The last eruption, occurred in the 1538, built up the Mt. Nuovo cone. The Campi Flegrei are subject to a slow vertical deformation, called bradyseism. In the 1970-1972 and 1982-1984 they have been affected by two intense episodes of ground upheaval (ac- companied by an intense seismic activity)0, followed by a subsidence phase, slower than uplift and still active. Though such phenomenon has not been followed by erup- tive events, it caused serious damages, emphasizing the high volcanic risk of the phle- grean caldera. The Ischia island, located SW of Naples, has been characterised by a volcanic activity both explosive and effusive, occurred mainly in the last 50,000 years. These events modelled the topography producing fault systems and structures delim- iting the Mt. Epomeo resurgent block. The last eruption has occurred on 1302. After, the dynamics of the island has been characterised by seismic activity (the strongest earthquake occurred on 1883) and by a meaningful subsidence, on the S and NW sec- tors of the island. The concentration of such many active volcanoes in an area with a dense urbanization (about 1,500,000 inhabitants live) needs systematic and contin- uous monitoring of the dynamics. These information are necessary in order to char- acterise eruptive precursors useful for modelling the volcanoes behaviour. Insofar, the entire volcanic Neapolitan area, characterised by a

  6. Hydrocarbon- Generating Model of the Area Covered With Volcanic Rock

    Guo Zhanqian; Zhang Yuwei


    The distribution of Oil & gas fields shows their close relationship with the most active tectonic regions. This is not a coincidence but having a scientific reasons. The crustal active regions, refer to the places where the active natural earthquake, volcanic activities, underground water happened, and the areas of the leaking off of natural gas to the surface of the crust. The magma of volcanic activities brings the organic "kitchen range body" hydrocarbon- generating model and inorganic genetic hydrocarbon to the regions covered by volcanic rock. Underground water brings a catalytic hydrocarbongenerating model for organic matter, and the leaking- off of H2 and CO2 contributes a synthetic hydrocarbon - generating model. Volcanic activities bring the assemblage of Source, Reservoir and Seal formed by the sediments and magma the sedimentary basins, and the hydrocarbon - generating system with a "water - volcano" binary structure is formed. All these conditions are favorable and excellent for the formation of oil & gas fields. The distribution of American oil & gas fields have very close relationship with the mines of Fe, Mn, Ct, Mo, W and V, deposits of Zn, Cu, V, Pb, Al and Hg, and the deposits of fluorite, sulfur, potassium salt, phosphate and halite, and the distribution of sulfate- chloride of river water. The reason why few oil & gas fields discovered in the regions covered by volcanic rock in western America maybe because of the view of "inconsistency between petroleum and volcano". Further more, It's very difficult to carry out a geophysical exploration in such kinds of regions.This paper examined a few hydrocarbon-generating models (systems) mentioned above and came up with some fresh ideas on the exploration in the areas covered with volcanic rocks.

  7. Volcanic risk perception in the Campi Flegrei area

    Ricci, T.; Barberi, F.; Davis, M. S.; Isaia, R.; Nave, R.


    The Campi Flegrei which includes part of the city of Naples, is an active volcanic system; its last eruption occurred in 1538 AD. More recently two significant crises occurred between 1969 and 72 and 1982-84 and were accompanied by ground movements (bradyseism) and seismic activity, forcing people of the town of Pozzuoli to be evacuated. Since 1984 development of a volcanic emergency plan has been underway. In 2000 Civil Protection published a risk map which defined the Red Zone, an area highly at risk from pyroclastic flows, which would need to be evacuated before an eruption. The first study to evaluate the volcanic risk perceptions of the people living within the Campi Flegrei area was completed in spring 2006, resulting in the largest sample ever studied on this topic except for one on Vesuvio area residents by Barberi et al. (2008). A 46 item questionnaire was distributed to 2000 of the approximately 300,000 residents of the Campi Flegrei Red Zone, which includes three towns and four neighborhoods within the city of Naples. A total of 1161 questionnaires were returned, for an overall response rate of 58%. Surveys were distributed to junior high and high school students, as well as to adult members of the general population. Results indicated that unlike issues such as crime, traffic, trash, and unemployment, volcanic hazards are not spontaneously mentioned as a major problem facing their community. However, when asked specific questions about volcanic risks, respondents believe that an eruption is likely and could have serious consequences for themselves and their communities and they are quite worried about the threat. Considering the events of 1969-72 and 1982-84, it was not surprising that respondents indicated earthquakes and ground deformations as more serious threats than eruptive phenomena. Of significant importance is that only 17% of the sample knows about the existence of the Emergency Plan, announced in 2001, and 65% said that they have not received

  8. Volcanic hazards of the Idaho National Engineering Laboratory and adjacent areas

    Hackett, W.R. [WRH Associates, Salt Lake City, UT (United States); Smith, R.P. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)


    Potential volcanic hazards are assessed, and hazard zone maps are developed for the Idaho National Engineering Laboratory (INEL) and adjacent areas. The basis of the hazards assessment and mapping is the past volcanic history of the INEL region, and the apparent similarity of INEL volcanism with equivalent, well-studied phenomena in other regions of active volcanism, particularly Hawaii and Iceland. The most significant hazards to INEL facilities are associated with basaltic volcanism, chiefly lava flows, which move slowly and mainly threaten property by inundation or burning. Related hazards are volcanic gases and tephra, and ground disturbance associated with the ascent of magma under the volcanic zones. Several volcanic zones are identified in the INEL area. These zones contain most of the volcanic vents and fissures of the region and are inferred to be the most probable sites of future INEL volcanism. Volcanic-recurrence estimates are given for each of the volcanic zones based on geochronology of the lavas, together with the results of field and petrographic investigations concerning the cogenetic relationships of INEL volcanic deposits and associated magma intrusion. Annual probabilities of basaltic volcanism within the INEL volcanic zones range from 6.2 {times} 10{sup {minus}5} per year (average 16,000-year interval between eruptions) for the axial volcanic zone near the southern INEL boundary and the Arco volcanic-rift zone near the western INEL boundary, to 1 {times} 10{sup {minus}5} per year (average 100,000-year interval between eruptions) for the Howe-East Butte volcanic rift zone, a geologically old and poorly defined feature of the central portion of INEL. Three volcanic hazard zone maps are developed for the INEL area: lava flow hazard zones, a tephra (volcanic ash) and gas hazard zone, and a ground-deformation hazard zone. The maps are useful in land-use planning, site selection, and safety analysis.

  9. High Resolution Aircraft Scanner Mapping of Geothermal and Volcanic Areas

    Mongillo, M.A.; Cochrane, G.R.; Wood, C.P.; Shibata, Y.


    High spectral resolution GEOSCAN Mkll multispectral aircraft scanner imagery has been acquired, at 3-6 m spatial resolutions, over much of the Taupo Volcanic Zone as part of continuing investigations aimed at developing remote sensing techniques for exploring and mapping geothermal and volcanic areas. This study examined the 24-band: visible, near-IR (NIR), mid-IR (MIR) and thermal-IR (TIR) imagery acquired over Waiotapu geothermal area (3 m spatial resolution) and White Island volcano (6 m resolution). Results show that color composite images composed of visible and NIR wavelengths that correspond to color infrared (CIR) photographic wavelengths can be useful for distinguishing among bare ground, water and vegetation features and, in certain cases, for mapping various vegetation types. However, combinations which include an MIR band ({approx} 2.2 {micro}m) with either visible and NIR bands, or two NIR bands, are the most powerful for mapping vegetation types, water bodies, and bare and hydrothermally altered ground. Combinations incorporating a daytime TIR band with NIR and MIR bands are also valuable for locating anomalously hot features and distinguishing among different types of surface hydrothermal alteration.

  10. Airborne magnetic mapping of volcanic areas - state-of-the-art and future perspectives

    Supper, Robert; Paoletti, Valeria; Okuma, Shigeo


    Traditionally airborne magnetics surveys in volcanology are used for mapping regional geological features, fault zones and to develop a magnetic model of the volcanic subsurface. Within an Austrian-Italian-Japanese cooperation, several volcanic areas including Mt. Vesuvius, Ischia, Campi Flegreii and Aeolian Islands in Italy and Socorro Island in Mexico were mapped by high-resolution magnetic mapping during the last 15 years. In this paper, general conclusions from this long-term cooperation project on airborne magnetics in volcanic areas will be summarised. Basically the results showed the results from airborne magnetics could be used for three major purposes: 1. Developing a rough model for the magnetisation below the volcano down to several kilometres by applying advanced magnetic inversion algorithms helped to define the possible depth of the current or past magma chamber. Due to the complexity of the subsurface of volcanic areas, inversion of data was much dependent on constraints coming from other geoscientific disciplines. 2. After applying certain steps of reduction (topographic correction, field transformation) and a combination of source selective filtering, important regional structural trends could be derived from the alignment of the residual magnetic anomalies. 3. On the other hand during recent years, research has also focused on repeated measurements of the magnetic field of volcanic areas (differential in respect of time = differential magnetic measurements - DMM) using airborne sensors. Long-term temporal magnetic field variations in active volcanic areas can be caused by a changing size of the magma chamber or a general rise in temperature. This is caused by the fact that magnetization disappears, when a magnetic material is warmed up over a certain temperature (Curie- temperature). In consequence the resulting total magnetic field changes. Therefore, determining areas showing changes in the magnetic field could help to select areas where a

  11. SURFACE AREA AND MICRO-ROUGHNESS OF VOLCANIC ASH PARTICLES: A case study, Acigol Volcanic Complex, Cappadocia, Central Turkiye

    Ersoy, O.; Aydar, E.; Sen, E.; Atici, G.


    Every single ash particle may convey information about its own formation environment and conditions. Certain features on particles may give a hint about the fragmentation regime, the intensity of fragmentation and quantity of water that partakes in the fragmentation process, etc. On this account, this study majored in the analysis on finer pyroclastic material, namely volcanic ash particles. Here, we used volcanic ash particles from Quaternary Acigol Volcanic complex (West of Nevsehir, Cappadocia, Central Turkiye). Quaternary Acigol Volcanic complex lies between the towns of Nevsehir and Acigol. It consists of a shallow caldera, a thick pyroclastic apron, seven obsidian dome clusters, and scattered cinder cones and associated lavas (Druitt et al., 1995). The products of explosive volcanism of the region were distinguished as two main Quaternary tuffs by a recent study (Druitt et al., 1995). Samples are from ashfall beds in a sequence of intercalated pumice fall, ashfall, and ignimbrite beds. In this study in order to achieve surface properties of volcanic ash particles, surface areas and micro-roughness of ash particles were measured on digital elevation models (DEM) reconstructed from stereoscopic images acquired on Scanning Electron Microscope (SEM) at varying specimen tilt angles. Correlation between surface texture of volcanic ash particles and eruption characteristics was determined.

  12. Automatic semi-continuous accumulation chamber for diffuse gas emissions monitoring in volcanic and non-volcanic areas

    Lelli, Matteo; Raco, Brunella; Norelli, Francesco; Virgili, Giorgio; Continanza, Davide


    Since various decades the accumulation chamber method is intensively used in monitoring activities of diffuse gas emissions in volcanic areas. Although some improvements have been performed in terms of sensitivity and reproducibility of the detectors, the equipment used for measurement of gas emissions temporal variation usually requires expensive and bulky equipment. The unit described in this work is a low cost, easy to install-and-manage instrument that will make possible the creation of low-cost monitoring networks. The Non-Dispersive Infrared detector used has a concentration range of 0-5% CO2, but the substitution with other detector (range 0-5000 ppm) is possible and very easy. Power supply unit has a 12V, 7Ah battery, which is recharged by a 35W solar panel (equipped with charge regulator). The control unit contains a custom programmed CPU and the remote transmission is assured by a GPRS modem. The chamber is activated by DataLogger unit, using a linear actuator between the closed position (sampling) and closed position (idle). A probe for the measure of soil temperature, soil electrical conductivity, soil volumetric water content, air pressure and air temperature is assembled on the device, which is already arranged for the connection of others external sensors, including an automatic weather station. The automatic station has been tested on the field at Lipari island (Sicily, Italy) during a period of three months, performing CO2 flux measurement (and also weather parameters), each 1 hour. The possibility to measure in semi-continuous mode, and at the same time, the gas fluxes from soil and many external parameters, helps the time series analysis aimed to the identification of gas flux anomalies due to variations in deep system (e.g. onset of volcanic crises) from those triggered by external conditions.

  13. Geomorphic assessment of late Quaternary volcanism in the Yucca Mountain area, southern Nevada: Implications for the proposed high-level radioactive waste repository

    Wells, S. G.; McFadden, L. D.; Renault, C. E.; Crowe, B. M.


    Volcanic hazard studies for high-level radioactive waste isolation in the Yucca Mountain area, Nevada, require a detailed understanding of Quaternary volcanism to forecast rates of volcanic processes. Recent studies of the Quaternary Cima volcanic field in southern California have demonstrated that K-Ar dates of volcanic landforms are consistent with their geomorphic and pedologic properties. The systematic change of these properties with time may be used to provide age estimates of undated or questionably dated volcanic features. The reliability off radiometric age determinations of the youngest volcanic center, Lathrop Wells, near the proposed Yucca Mountain site in Nevada has been problematic. In this study, a comparison of morphometric, pedogenic, and stratigraphic data establishes that correlation of geomorphic and soil properties between the Cima volcanic field and the Yucca Mountain area is valid. Comparison of the Lathrop Wells cinder cone to a 15-20 ka cinder cone in California shows that their geomorphic-pedogenic properties are similar and implies that the two cones are of similar age. We conclude that previous determinations of ca. 0.27 Ma for the latest volcanic activity at Lathrop Wells, approximately 20 km from the proposed repository, may be in error by as much as an order of magnitude and that the most recent volcanic activity is no older than 20 ka.

  14. Volcanic risk perception of young people in the urban areas of Vesuvius: Comparisons with other volcanic areas and implications for emergency management

    Carlino, S.; Somma, R.; Mayberry, G.C.


    More than 600 000 people are exposed to volcanic risk in the urban areas near the volcano, Vesuvius, and may need to be evacuated if there is renewed volcanic activity. The success of a future evacuation will strongly depend on the level of risk perception and preparedness of the at-risk communities during the current period of quiescence. The volcanic risk perception and preparedness of young people is of particular importance because hazard education programs in schools have been shown to increase the clarity of risk perception and students often share their knowledge with their parents. In order to evaluate young people's risk perception and preparedness for a volcanic crisis, a multiple choice questionnaire was distributed to 400 high-school students in three municipalities located close to the volcano. The overall results suggest that despite a 60-year period of quiescence at Vesuvius, the interviewed students have an accurate perception of the level of volcanic risk. On the other hand, the respondents demonstrate a clear lack of understanding of volcanic processes and their related hazards. Also, the interviewed students show high levels of fear, poor perceived ability to protect themselves from the effects of a future eruption, and insufficient knowledge of the National Emergency Plan for Vesuvian Area (NEPVA). The latter result suggests that in comparison with volcanic crises in other regions, during a future eruption of Vesuvius, there may not be enough time to educate the large number of people living near the volcano about how to appropriately respond. The inadequate risk education and preparedness of respondents implies that a strong effort is needed to improve communication strategies in order to facilitate successful evacuations. Therefore, it is important to take advantage of the present period of quiescence at Vesuvius to improve the accuracy of risk perception of youth in local communities. ?? 2008.

  15. Volcanic hazard and risk assessment in a multi-source volcanic area: the example of Napoli city (Southern Italy

    I. Alberico


    Full Text Available The possible emplacement of pyroclastic fall and flow products from Campi Flegrei and Somma-Vesuvio represents a threat for the population living in Napoli city. For this area, the volcanic hazard was always partially investigated to define the hazard related to the Campi Flegrei or to the Somma-Vesuvio activity one at a time. A new volcanic hazard and risk assessment, at the municipality scale, as a vital tool for decision-making about territorial management and future planning, is presented here.

    In order to assess the hazard related to the explosive activity of both sources, we integrated the results of field studies and numerical simulations, to evaluate the future possibility for Napoli to be hit by the products of an explosive eruption. This is defined for the Somma Vesuvio central volcano through the sum of "field frequency" based on the thickness and distribution of past deposits (Lirer et al., 2001, and for the Campi Flegrei volcanic field by suitably processing simulated events based on numerical modelling (Alberico et al., 2002; Costa et al., 2009. Aiming at volcanic risk assessment, the hazard areas were joined with the exposure map, considered for our purposes as the economical value of artefacts exposed to hazard. We defined four risk classes, and argued that the medium and low-very low risk classes have the largest extent in Napoli municipality, whereas only few zones located in the eastern part of the city and in the westernmost coastal area show a high risk, owing to the correspondence of high economical value and high hazard.

  16. Geochemical Characteristics of Danfeng Meta-Volcanic Rocks in Shangzhou Area,Shaanxi Province


    The Danfeng meta-volcanics in the Shangzhou area, Shaanxi Province are characterized by oceanic island arc volcanic geochemistry. They are a suite of low-K tholeiitic series and calc-alkaline series meta-volcanic rocks derived from different sources respectively.These meta-volcanics have high Th/Ta ratios and low contents of Ni,Ta,Ti,Y and Yb, suggesting that they were influenced by the subduction zone components.Many lines of evidence show that the Danfeng meta-volcanics were produced in an oceanic island are setting of the supra-subduction zone at the southern margin of the North China Block during the Early Paleozoic.

  17. Geophysical imaging of subsurface structures in volcanic area by seismic attenuation profiling

    Tsuru, Tetsuro; No, Tetsuo; Fujie, Gou


    Geophysical imaging by using attenuation property of multichannel seismic reflection data was tested to map spatial variation of physical properties of rocks in a volcanic area. The study area is located around Miyakejima volcanic island, where an intensive earthquake swarm was observed associated with 2000 Miyakejima eruption. Seismic reflection survey was conducted five months after the swarm initiation in order to clarify crustal structure around the hypocenters of the swarm activity. However, the resulting seismic reflection profiles were unable to provide significant information of deep structures around the hypocenters. The authors newly applied a seismic attribute method that focused seismic attenuation instead of reflectivity to the volcanic area, and designed this paper to assess the applicability of this method to subsurface structural studies in poorly reflective volcanic areas. Resulting seismic attenuation profiles successfully figured out attenuation structures around the Miyakejima volcanic island. Interestingly, a remarkable high-attenuation zone was detected between Miyakejima and Kozushima islands, being well correlated with the hypocenter distribution of the earthquake swarm in 2000. The high-attenuation zone is interpreted as a fractured area that was developed by magma activity responsible for the earthquake swarms that have been repeatedly occurring there. The present study can be one example showing the applicability of seismic attenuation profiling in a volcanic area. [Figure not available: see fulltext. Caption: .

  18. Magmatic Source Composition and Magmatism of the Volcanic Rocks in the Area of Kuruktag, Southern Xinjiang

    JIANG Changyi; BAI Kaiyin; HI Aizhi; ZHAO Xiaoning; ZHANG Hongbo


    In the Sinian-Cambrian strata in the area of Kuruktag, southern Xingjiang, four layers of volcanic rocks occurred in the Early Sinian Beiyixi Formation, Late Sinian Zhamoketi Formation and Shuiquan Formation, and Early Cambrian Xishanbulake Formation, respectively. Volcanics of the Shuiquan Formation and Xishanbulake Formation are of alkali basalt series, those of the Zhamoketi Formation are of alkali basalt series and tholeiite series, and those of the Beiyixi Formation are obviously characterized by bimodal assemblage and mostly belong to alkali volcanics. Multi-element distribution patterns of the rocks show continental tumescence characters of interplate basalt.Fractional crystallization of plagioclase led to negative Eu-anomalies of some volcanics and the cumulation of olivine resulted in high MgO and low SiO2 content of some volcanic rocks. The SiO2 saturability of volcanic rocks of the Xishanbulake Formation and Shuiquan Formation is lower than that of tholeiite of the Zhamoketi Formation. Correspondingly, the abundance of incompatible elements in the first two formations is higher than those in the last formation, and the differences can be attributed to the different degrees of partial melting. The intense fractionation of REE and the obvious depletion of HREE suggest that these volcanic rocks were derived from garnet Iherzolite of the mantle in the continental lithosphere. The Ba/Nb, La/Nb, Ba/La, Ba/Th and Rb/Nb rations demonstrate that these volcanic rocks were exclusively derived from the enriched mantle, mainly the EMI type mantle.

  19. Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results

    de Lauro, E.; de Martino, S.; Falanga, M.; Palo, M.


    We investigate the physical processes associated with volcanic tremor and explosions. A volcano is a complex system where a fluid source interacts with the solid edifice so generating seismic waves in a regime of low turbulence. Although the complex behavior escapes a simple universal description, the phases of activity generate stable (self-sustained) oscillations that can be described as a non-linear dynamical system of low dimensionality. So, the system requires to be investigated with non-linear methods able to individuate, decompose, and extract the main characteristics of the phenomenon. Independent Component Analysis (ICA), an entropy-based technique is a good candidate for this purpose. Here, we review the results of ICA applied to seismic signals acquired in some volcanic areas. We emphasize analogies and differences among the self-oscillations individuated in three cases: Stromboli (Italy), Erebus (Antarctica) and Volcán de Colima (Mexico). The waveforms of the extracted independent components are specific for each volcano, whereas the similarity can be ascribed to a very general common source mechanism involving the interaction between gas/magma flow and solid structures (the volcanic edifice). Indeed, chocking phenomena or inhomogeneities in the volcanic cavity can play the same role in generating self-oscillations as the languid and the reed do in musical instruments. The understanding of these background oscillations is relevant not only for explaining the volcanic source process and to make a forecast into the future, but sheds light on the physics of complex systems developing low turbulence.


    Gonzalez, T.; Ortiz, I.


    Analysis and interpretation of gravimetric anomalies over the Occidental-Central Mexican Volcanic Belt, sheds new light on the subsurface structure of the Ixtlan de los Hervores, geothermal area. In Mexico, there are several geothermal areas that have been exploited commercially (Cerro Prieto, Los Azufres, Los Humeros, Tres Virgenes fields). However, there are many other known fields that have not been exploited. This is the case in the area of "Ixtlan de los Hervores" in the state of Michoacan. The analyzed region covers a rectangular area, aproximality from 20o N to 20.5° N and 102° W to 102.2°W. In the region there are thick basalt flows. The area is characterized by low and elongated hills formed by volcanic flows and on a smaller scale lacustrian sediments and major normal faults with a NW-SE direction particularly, the Ixtlan-Encinal fault which controls the trace of the Duero River and the Pajacuarán fault. The anomaly map was compared with the surface geology and the anomalies were correlated with major volcanic features, since our main interest was in mapping the subsurface faults and volcanic bodies. Two profiles were selected that cross major anomalies and the geothermal zone of Ixtlan. The Talwani algorithm for 2-D polygonal bodies has been used for calculating the theoretical anomalies. The proposed models adequately explain the main observed geological features. The models are made up of two lithostratigraphic units of volcanic rocks, represented by the Tertiary basalts, which adequately reflect the area's volcanic environment. These basaltic units, corresponding to different volcanic events were cut by the Ixtlan well. Both models reflect the existence of the Ixtlan-Encinal fault, the most important feature in the area which is also responsible for the existence of the geothermal area.

  1. 200 Area Interim Storage Area Technical Safety Requirements



    The 200 Area Interim Storage Area Technical Safety Requirements define administrative controls and design features required to ensure safe operation during receipt and storage of canisters containing spent nuclear fuel. This document is based on the 200 Area Interim Storage Area, Annex D, Final Safety Analysis Report which contains information specific to the 200 Area Interim Storage Area.

  2. Geochemical modeling of groundwater evolution in a volcanic aquifer system of Kumamoto area, Japan

    Hossain, S.; Hosono, T.; Ide, K.; Shimada, J.


    Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater in a volcanic aquifer system of Kumamoto area (103 Km2) in southern Japan. The modeling was based on flow paths proposed by different researcher using different techniques, and detailed chemical analysis of groundwater along the flow paths. Potential phases were constrained using general trends in hydrochemical data of groundwater, mineralogical data, and saturation indices data of minerals in groundwater. Hydrochemical data from a total of 180 spring, river and well water samples were used to evaluate water quality and to determine processes that control groundwater chemistry. The samples from the area were classified as recharge zone water (Ca-HCO3 and Ca-SO4 type), lateral flow to discharge zone water (Ca-HCO3 and Na-HCO3 type) and stagnant zone water (Na-Cl type). The inverse geochemical modeling demonstrated that relatively few phases are required to derive water chemistry in the area. The downstream changes in groundwater chemistry could be largely explained by the weathering of plagioclase to kaolinite, with possible contributions from weathering of biotite and pyroxene. In a broad sense, the reactions responsible for the hydrochemical evolution in the area fall into three categories (1) silicate weathering reactions (2) precipitation of amorphous silica and clay minerals and (3) Cation exchange reactions of Ca2+ to Na+.

  3. Surface area and volume measurements of volcanic ash particles by SEM stereoscopic imaging

    Ersoy, Orkun


    Surface area of volcanic ash particles is of great importance to research including plume dynamics, particle chemical and water reactions in the plume, modelling (i.e. plume shape, particle interactions , dispersion etc.), remote sensing of transport and SO2, HCl, H2O, CO2 levels, forecasting plume location, and transportation and deposition of ash particles. The implemented method presented in this study offer new insights for surface characterization of volcanic ash particles on macro-pore regions. Surface area and volumes of volcanic ash particles were measured using digital elevation models (DEM) reconstructed from stereoscopic images acquired from different angles by scanning electron microscope (SEM). The method was tested using glycidyl methacrylate (GMA) micro-spheres which exhibit low spherical imperfections. The differences between measured and geometrically calculated surface areas were introduced for both micro-spheres and volcanic ash particles in order to highlight the probable errors in modelling on volcanic ash behaviour. The specific surface areas of volcanic ash particles using this method are reduced by half (from mean values of 0.045 m2/g to 0.021 m2/g) for the size increment 63 μm to 125 μm. Ash particles mostly have higher specific surface area values than the geometric forms irrespective of particle size. The specific surface area trends of spheres and ash particles resemble for finer particles (63 μm). Approximation to sphere and ellipsoid have similar margin of error for coarser particles (125 μm) but both seem to be inadequate for representation of real ash surfaces.

  4. The Boring Volcanic Field of the Portland-Vancouver area, Oregon and Washington: tectonically anomalous forearc volcanism in an urban setting

    Evarts, Russell C.; Conrey, Richard M.; Fleck, Robert J.; Hagstrum, Jonathan T.; O'Connor, Jim; Dorsey, Rebecca; Madin, Ian P.


    More than 80 small volcanoes are scattered throughout the Portland-Vancouver metropolitan area of northwestern Oregon and southwestern Washington. These volcanoes constitute the Boring Volcanic Field, which is centered in the Neogene Portland Basin and merges to the east with coeval volcanic centers of the High Cascade volcanic arc. Although the character of volcanic activity is typical of many monogenetic volcanic fields, its tectonic setting is not, being located in the forearc of the Cascadia subduction system well trenchward of the volcanic-arc axis. The history and petrology of this anomalous volcanic field have been elucidated by a comprehensive program of geologic mapping, geochemistry, 40Ar/39Ar geochronology, and paleomag-netic studies. Volcanism began at 2.6 Ma with eruption of low-K tholeiite and related lavas in the southern part of the Portland Basin. At 1.6 Ma, following a hiatus of ~0.8 m.y., similar lavas erupted a few kilometers to the north, after which volcanism became widely dispersed, compositionally variable, and more or less continuous, with an average recurrence interval of 15,000 yr. The youngest centers, 50–130 ka, are found in the northern part of the field. Boring centers are generally monogenetic and mafic but a few larger edifices, ranging from basalt to low-SiO2 andesite, were also constructed. Low-K to high-K calc-alkaline compositions similar to those of the nearby volcanic arc dominate the field, but many centers erupted magmas that exhibit little influence of fluids derived from the subducting slab. The timing and compositional characteristics of Boring volcanism suggest a genetic relationship with late Neogene intra-arc rifting.

  5. S-wave velocity structure inferred from receiver function inversion in Tengchong volcanic area

    贺传松; 王椿镛; 吴建平


    Tengchong volcanic area is located near the impinging and underthrust margin of India and Eurasia plates. The volcanic activity is closely related to the tectonic environment. The deep structure characteristics are inferred from the receiver function inversion with the teleseismic records in the paper. The results show that the low velocity zone is influenced by the NE-trending Dayingjiang fault. The S-wave low velocity structure occurs obviously in the southern part of the fault, but unobviously in its northern part. There are low velocity zones in the shallow position, which coincides with the seismicity. It also demonstrates that the low velocity zone is directly related to the thermal activity in the volcanic area. Therefore, we consider that the volcano may be alive again.

  6. Young Volcanism on 20 Million Year Old Seafloor: The DISCOL Area, Nazca Plate.

    Devey, C. W.; Boetius, A.; Kwasnitschka, T.; Augustin, N.; Yeo, I. A.; Greinert, J.


    Volcanism in the ocean basins is traditionally assumed to occur only at the plate margins (mid-ocean ridges, subduction zones, possibly also transform boundaries) and areas of intraplate hotspot activity related to thermal plumes in the mantle. As a result, abyssal areas away from hotspots are seldom explored systematically for signs of volcanism and are generally regarded as volcanically "dead". Here we present serendipitous results from the Peru Basin, a site of Mn-nodule accumulation which was targetted in 1989 for a large-scale disturbance experiment (the DISCOL experiment) to simulate the effects of seabed nodule mining. The area is truly intraplate - it is 700 km from the south American subduction zone or the Galapagos Islands and 2000 km from the East Pacific Rise. A return trip to DISCOL in 2015 to assess the extent of environmental recovery also included a remotely-operated underwater vehicle (ROV) dive on a small (300m high) seamount adjacent to the Mn-nodule field. ROV video records show the seamount is generally heavily sedimented but has a small (100x150m) pillow mound and an area of indurated calcareous sediments apparently cut by basaltic dykes near its summit. The summit is also cut by N-S and E-W-trending faults, some with up to 20m of throw, whose scarps expose thick sedimentary sequences. The virtual absence of sediment covering the pillows or dyke outcrops suggest that they are very recent - the thick sediment pile exposed on the fault scarps suggests that they were erupted on top of an old seamount. Regionally, acoustic data (bathymetry and backscatter from the ship-mounted multibeam system) shows several other seamounts in the region which may have experienced recent volcanic activity, although no sign of a linear volcanic chain is seen. Taken together, these observations suggest that, even at age 20Ma, the Nazca Plate is volcanically active.

  7. Seismological study on the crustal structure of Tengchong volcanic-geothermal area

    王椿镛; 楼海; 吴建平; 白志明; 皇甫岗; 秦嘉政


    Based upon the deep seismic sounding profile conducted in the Tengchong volcanic-geothermal area, a two-dimensional crustal P velocity structure is obtained by use of the finite-difference inversion and the forward travel-time fitting method. The crustal model shows that there is a low velocity zone in upper crust in the Tengchong area, which may be related to the volcanic-geothermal activities, and two intracrustal faults (the Longling-Ruili fault and Tengchong fault) exist on the profile, where the Tengchong fault may extend to the Moho discontinuity. Meanwhile, based on teleseismic data recorded by a temporary seismic network, we obtained the S-wave velocity structures beneath the Rehai-Retian region in the Tengchong area, which show the low S-wave velocity anomaly in upper crust. The authors discuss the causes of Tengchong volcanic eruption based on the deep crustal structure. The crustal structure in the Tengchong volcanic-geothermal area is characterized by low P-wave and S-wave velocity, low resistivity, high heat-flow value and low Q value. The P-wave velocity in the upper mantle is also low. For this information, it can be induced that the magma in the crust is derived from the upper mantle, and the low velocity anomaly in upper crust in the Tengchong area may be related to the differentiation of magma. The Tengchong volcanoes are close to an active plate boundary and belong to "plate boundary" volcanoes.

  8. Radium isotopes in groundwater around Fuji Volcano, Japan -application for groundwater dating on volcanic area-

    Ohta, T.; Mahara, Y.


    Young groundwater dating less than 100 years is possible to be obtained from environmental radioactivity with short half life, 3H+3He, 85Kr, or chemical material, CFC-12. The 3H+3He dating method is excellent method to estimate the residence time of shallow groundwater. The one of advantage of the method is small sample volume. The 3He in groundwater is originated by 3 sources, tritiogenic He, mantle He, radiogenic He produced in rock. Especially, as the contribution of the mantle He is greater than the radiogenic and triogenic, when 3H+3He dating apply for groundwater dating on volcanic area, we have to determine ratio of 3 sources. On the other hand, as 85Kr is only originated from atmosphere, it is excellent groundwater dating tracer on volcanic area. However, as 85Kr is ultra low concentration in groundwater, 85Kr is needed to separate from large amount of ground water about 10^5 L. Young groundwater dating by these methods has both advantages and disadvantages, but the disadvantages of the individual methods can be offset by using multiple tracers. Development of a lot of groundwater dating techniques is desired. Therefore, an application of radium isotopes which is simple origin to groundwater dating on volcanic area was tried. Ra-228 and Ra-226 are progenies of Th and U, respectively. The 228Ra/226Ra in ground waters depends on the Th/U in the relevant rocks. As the 228Ra and 226Ra in shallow groundwater on volcanic area are originated from only rock, and the collection of radium isotopes from groundwater is easier than that of 85Kr, implying that it is possible to be good tracer for volcanic area. We aim that groundwater age obtain from 228Ra/226Ra in groundwater and relevant rock on volcanic area. We determined that 228Ra/226Ra observed with river waters and the relevant rocks. The method applied for Kakitagawa around Fuji Volcano, Japan. The relevant rock of Kakitagawa is Mishima lava flow. Our method compared with 3H+3He dating. The residence time of

  9. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Hackett, W.R.; Smith, R.P.


    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  10. Quaternary volcanism, tectonics, and sedimentation in the Idaho National Engineering Laboratory area

    Hackett, W.R.; Smith, R.P.


    In this article, we discuss the regional context and describe localities for a two-day field excursion in the vicinity of the Idaho National Engineering Laboratory (INEL). We address several geologic themes: (1) Late Cenozoic, bimodal volcanism of the Eastern Snake River Plain (ESRP), (2) the regional tectonics and structural geology of the Basin and Range province to the northwest of the ESRP, (3) fluvial, lacustrine, and aeolian sedimentation in the INEL area, and (4) the influence of Quaternary volcanism and tectonics on sedimentation near the INEL.

  11. Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results

    E. De Lauro


    Full Text Available We investigate the physical processes associated with volcanic tremor and explosions. A volcano is a complex system where a fluid source interacts with the solid edifice so generating seismic waves in a regime of low turbulence. Although the complex behavior escapes a simple universal description, the phases of activity generate stable (self-sustained oscillations that can be described as a non-linear dynamical system of low dimensionality. So, the system requires to be investigated with non-linear methods able to individuate, decompose, and extract the main characteristics of the phenomenon. Independent Component Analysis (ICA, an entropy-based technique is a good candidate for this purpose. Here, we review the results of ICA applied to seismic signals acquired in some volcanic areas. We emphasize analogies and differences among the self-oscillations individuated in three cases: Stromboli (Italy, Erebus (Antarctica and Volcán de Colima (Mexico. The waveforms of the extracted independent components are specific for each volcano, whereas the similarity can be ascribed to a very general common source mechanism involving the interaction between gas/magma flow and solid structures (the volcanic edifice. Indeed, chocking phenomena or inhomogeneities in the volcanic cavity can play the same role in generating self-oscillations as the languid and the reed do in musical instruments. The understanding of these background oscillations is relevant not only for explaining the volcanic source process and to make a forecast into the future, but sheds light on the physics of complex systems developing low turbulence.

  12. The Albano multiple-maar center (Rome, Italy): an active volcanic area since 70 ka

    Freda, C.; Gaeta, M.; Karner, D. B.; Marra, F.; Renne, P. R.; Scarlato, P.; Taddeucci, J.


    The Albano multiple-maar center hosted the most recent activity of the Alban Hills Volcanic District. The determination of its petrochemical characteristics and its geochronology is therefore of great importance in order to evaluate the status of this volcanic area and to assess the possible volcanic hazard for Rome. Despite the detailed 40Ar/39Ar geochronologic history of the products of its activity, relatively poor information on the stratigraphy and the petrology of this volcanic center exists. In order to develop a detailed chronostratigraphy, petrology, and a more thorough knowledge of the eruptive mechanisms that characterized the recent activity of the Albano center, a joint research project is being conducted by scientists from the Istituto Nazionale di Geofisica e Vulcanologia, the University of California at Berkeley, and the Berkeley Geochronology Center. Here we have studied the most complete stratigraphic section located within the northern crater rim of Albano, where most of the products are exposed. We have investigated proximal and distal outcrops, in order to correlate them to the units identified in the northern crater rim section. We will present our recently acquired geochronologic and petrochemical data, which indicates magma chamber recharge associated with this <70 ka volcanism.

  13. A preliminary evaluation of ERTS-1 images on the volcanic areas of Southern Italy

    Cassinis, R.; Lechi, G. M.


    The test site selected for the investigation covers nearly all the regions of active and quiescent volcanism in southern Italy, i.e. the eastern part of the island of Sicily, the Aeolian Islands and the area of Naples. The three active European volcanoes (Etna, Stromboli and Vesuvius) are included. The investigation is in the frame of a program for the surveillance of active volcanoes by geophysical (including remote sensing thermal methods) and geochemical methods. By the multispectral analysis of ERTS-1 data it is intended to study the spectral behavior of the volcanic materials as well as the major geological lineaments with special reference to those associated with the volcanic region. Secondary objectives are also the determination of the hydrographic network seasonal behavior and the relationship between the vegetation cover and the different type of soils and rocks.

  14. Neogene seismites and seismic volcanic rocks in the Linqu area, Shandong Province, E China

    Tian H.S.


    Full Text Available The Yishu Fault Zone runs through the centre of Shandong Province (E China; it is a deep-seated large fault system that still is active. Two volcanic faulted basins (the Shanwang and Linqu Basins in the Linqu area, west of the fault zone, are exposed to rifting, which process is accompanied by a series of tectonic and volcanic earthquakes with a magnitude of 5-8. Lacustrine sediments in the basins were affected by these earthquakes so that seismites with a variety of soft-sediment deformation structures originated. The seismites form part of the Shanwang Formation of the Linqu Group. Semi-consolidated fluvial conglomerates became deformed in a brittle way; these seismites are present at the base of the Yaoshan Formation. Intense earthquakes triggered by volcanic activity left their traces in the form of seismic volcanic rocks associated with liquefied-sand veins in the basalt/sand intercalations at the base of the Yaoshan Formation. These palaeo-earthquake records are dated around 14-10 Ma; they are responses to the intense tectonic extension and the basin rifting in this area and even the activity of the Yishu Fault Zone in the Himalayan tectonic cycle.

  15. Structural model of the Northern Latium volcanic area constrained by MT, gravity and aeromagnetic data

    P. Gasparini


    Full Text Available The results of about 120 magnetotelluric soundings carried out in the Vulsini, Vico and Sabatini volcanic areas were modeled along with Bouguer and aeromagnetic anomalies to reconstruct a model of the structure of the shallow (less than 5 km of depth crust. The interpretations were constrained by the information gathered from the deep boreholes drilled for geothermal exploration. MT and aeromagnetic anomalies allow the depth to the top of the sedimentary basement and the thickness of the volcanic layer to be inferred. Gravity anomalies are strongly affected by the variations of morphology of the top of the sedimentary basement, consisting of a Tertiary flysch, and of the interface with the underlying Mesozoic carbonates. Gravity data have also been used to extrapolate the thickness of the neogenic unit indicated by some boreholes. There is no evidence for other important density and susceptibility heterogeneities and deeper sources of magnetic and/or gravity anomalies in all the surveyed area.

  16. Volcanic succession of the Borovnik Member (Mohorje Formation, Bloke Plateau area, Central Slovenia

    Stevo Dozet


    Full Text Available A 75 m thick volcanic succession of the Borovnik Member, Mohorje Formation in the Bloke Plateau area consistsof dacitic and rhyolitic rocks deposited in a shallow-marine environment. Volcanic activity begun with lavaflows that underwent extensive disintegration, autobrecciation and mixing with the underlying unconsolidated fine-grained clastic sediments producing dacite/rhyolite-siltstone peperites. Peperites are very rich in fractured plagioclase phenocrysts, and owing to the incorporation of clastic material, they are commonly depleted in silica.The overlying fining-upward pyroclastic sequence is monotonous. Basal parts mainly consist of coarse-grained vitric tuffs that may contain some smaller pumice lapilli. The overlying volcaniclastics are fine-grained vitric tuffs,and in the uppermost parts of the sequence, they are interbedded with cherts.The study confirms the existence of primary volcaniclastic succession in the Bloke Plateau area and excludes its epiclastic or reworked origin.

  17. A Petrographic and Mineralogical Study of Volcanic Rocks from the Mayaxueshan Area, North Qilian Fold Belt, NW China

    徐达伟; 萧炎宏


    The Ordovician volcanic rocks in the Mayaxueshan area have been pervasively altered or metamorphosedand contain abundant secondary minerals such as albite, chlorite, epidote, prehnite, pumpellyite, actinolite, titanite, quartz,and/or calcite. They were denoted as spilites or spilitic rocks in terms of their petrographic features and mineral assem-blages. The metamorphic grades of the volcanic rocks are equivalent to that of the intercalated metaclastic rocks. Thisindicates that both the spilitic volcanic rocks and metaclastic rocks in the Mayaxueshan area have formed as a result ofCaledonian regional metamorphism. We suggest that the previously denoted spilitic rocks or altered volcanic rocks shouldbe re-denoted as metabasalts or metabasaltic rocks. The metamorphic grade of the volcanic rocks increases with their age:prehnite-pumpellyite facies for the upper part of the Middle Ordovician volcanic rocks, prehnite-pumpellyite to lowergreenschist facies for the lower part of the Middle Ordovician volcanic rocks, and lower greenschist facies for the LowerOrdovician volcanic rocks. The P-T conditions are estimated as T = 240 - 290C and P = 1.5 - 4.5 kbar for the lower partof the Middle Ordovician rocks, and T = ~ 300~C for the Lower Ordovician rocks. The variations of mineral assemblagesoccurring at different domains of the volcanic rocks were controlled by the variations of the effective bulk composition inthose domains during metamorphism. The geochemical characteristics of Mg-Al chromite in the Mayaxueshan volcanicrocks are consistent with an origin of island arc environment.

  18. Material sources of escaped gases from Tianchi volcanic geothermal area, Changbai Mountains

    上官志冠; 郑雅琴; 董继川


    On the basis of the chemical components and stable isotopic compositions of escaped gases from the Tianchi volcanic geothermal area, the material sources of these gases are discussed, presenting that they are mainly derived from the residual mantle-derived magma in the crust; Changbai geothermal area may be directly interlinked with the eruption canal in history; there is a stable reservoir of the geothermal water and the deep-seated gases under the Changbai geothermal area, with water temperature of the reservoir being about (166±9)℃.

  19. Overview of electromagnetic methods applied in active volcanic areas of western United States

    Skokan, Catherine K.


    A better understanding of active volcanic areas in the United States through electromagnetic geophysical studies received foundation from the many surveys done for geothermal exploration in the 1970's. Investigations by governmental, industrial, and academic agencies include (but are not limited to) mapping of the Cascades. Long Valley/Mono area, the Jemez volcanic field, Yellowstone Park, and an area in Colorado. For one example — Mt. Konocti in the Mayacamas Mountains, California — gravity, magnetic, and seismic, as well as electromagnetic methods have all been used in an attempt to gain a better understanding of the subsurface structure. In each of these volcanic regions, anomalous zones were mapped. When conductive, these anomalies were interpreted to be correlated with hydrothermal activity and not to represent a magma chamber. Electrical and electromagnetic geophysical methods can offer valuable information in the understanding of volcanoes by being the method which is most sensitive to change in temperature and, therefore, can best map heat budget and hydrological character to aid in prediction of eruptions.

  20. Identification of geothermal system using 2D audio magnetotelluric method in Telomoyo volcanic area

    Romadlon, Arriqo'Fauqi; Niasari, Sintia Windhi


    Geothermal area of Candi Umbul Telomoyo is one of geothermal fields in Indonesia. This geothermal field is located in the Grabag district, Magelang, Central Java. This geothermal field was formed in a volcanic quarter. The main aim in this study is to identify geothermal system at Telomoyo volcanic area through synthetic model analysis. There are surface manifestations such as warm springs and altered rocks. Results of geochemistry study showed reservoir's temperature was 230°C. The Warm spring in Candi Umbul was the outflow zone of the Telomoyo geothermal system. The Telomoyo geothermal system was indicated chloride-bicarbonate type of warm spring. In addition, the results of geological mapping indicate that the dominant fault structure has southwest-northeast orientation. The fault was caused by the volcanic activity of mount Telomoyo. In this research conducted data analysis from synthetics model. It aims to estimate the response of magnetotelluric methods in various models of geothermal systems. In this study, we assumed three models of geothermal system in Candi Umbul-Telomoyo area. From the data analysis it was known that the model 1 and model 2 can be distinguished if the measurements were conducted in a frequency range of 0.01 Hz to 1000 Hz. In response of tipper (Hz) had a small value on all models at all measurement points, so the tipper cannot distinguish between model 1, model 2 and model 3. From this analysis was known that TM mode is more sensitive than TE mode at the resistivity and phase responses.

  1. Program Estimates Areas Required By Electronic Designs

    Cox, Brian


    PSIZE computer program calculates space required for electronic design. Reads in parts-list file and file containing required area for each type of part. Both unit areas of components and inherent additional space requirements taken into account. Written by use of AWK utility for Sun4-series computers running SunOS 4.x and IBM PC-series and compatible computers running MS-DOS. Sun version (NPO-19589). PC version (NPO-19065).

  2. Geology, geochronology, and paleogeography of the southern Sonoma volcanic field and adjacent areas, northern San Francisco Bay region, California

    Wagner, D.L.; Saucedo, G.J.; Clahan, K.B.; Fleck, R.J.; Langenheim, V.E.; McLaughlin, R.J.; Sarna-Wojcicki, A. M.; Allen, J.R.; Deino, A.L.


    Recent geologic mapping in the northern San Francisco Bay region (California, USA) supported by radiometric dating and tephrochronologic correlations, provides insights into the framework geology, stratigraphy, tectonic evolution, and geologic history of this part of the San Andreas transform plate boundary. There are 25 new and existing radiometric dates that define three temporally distinct volcanic packages along the north margin of San Pablo Bay, i.e., the Burdell Mountain Volcanics (11.1 Ma), the Tolay Volcanics (ca. 10-8 Ma), and the Sonoma Volcanics (ca. 8-2.5 Ma). The Burdell Mountain and the Tolay Volcanics are allochthonous, having been displaced from the Quien Sabe Volcanics and the Berkeley Hills Volcanics, respectively. Two samples from a core of the Tolay Volcanics taken from the Murphy #1 well in the Petaluma oilfield yielded ages of 8.99 ?? 0.06 and 9.13 ?? 0.06 Ma, demonstrating that volcanic rocks exposed along Tolay Creek near Sears Point previously thought to be a separate unit, the Donnell Ranch volcanics, are part of the Tolay Volcanics. Other new dates reported herein show that volcanic rocks in the Meacham Hill area and extending southwest to the Burdell Mountain fault are also part of the Tolay Volcanics. In the Sonoma volcanic field, strongly bimodal volcanic sequences are intercalated with sediments. In the Mayacmas Mountains a belt of eruptive centers youngs to the north. The youngest of these volcanic centers at Sugarloaf Ridge, which lithologically, chemically, and temporally matches the Napa Valley eruptive center, was apparently displaced 30 km to the northwest by movement along the Carneros and West Napa faults. The older parts of the Sonoma Volcanics have been displaced at least 28 km along the RodgersCreek fault since ca. 7 Ma. The Petaluma Formation also youngs to the north along the Rodgers Creek-Hayward fault and the Bennett Valley fault. The Petaluma basin formed as part of the Contra Costa basin in the Late Miocene and was

  3. Reservoir characteristics and control factors of Carboniferous volcanic gas reservoirs in the Dixi area of Junggar Basin, China

    Ji'an Shi


    Full Text Available Field outcrop observation, drilling core description, thin-section analysis, SEM analysis, and geochemistry, indicate that Dixi area of Carboniferous volcanic rock gas reservoir belongs to the volcanic rock oil reservoir of the authigenic gas reservoir. The source rocks make contact with volcanic rock reservoir directly or by fault, and having the characteristics of near source accumulation. The volcanic rock reservoir rocks mainly consist of acidic rhyolite and dacite, intermediate andesite, basic basalt and volcanic breccia: (1 Acidic rhyolite and dacite reservoirs are developed in the middle-lower part of the structure, have suffered strong denudation effect, and the secondary pores have formed in the weathering and tectonic burial stages, but primary pores are not developed within the early diagenesis stage. Average porosity is only at 8%, and the maximum porosity is at 13.5%, with oil and gas accumulation showing poor performance. (2 Intermediate andesite and basic basalt reservoirs are mainly distributed near the crater, which resembles the size of and suggests a volcanic eruption. Primary pores are formed in the early diagenetic stage, secondary pores developed in weathering and erosion transformation stage, and secondary fractures formed in the tectonic burial stage. The average porosity is at 9.2%, and the maximum porosity is at 21.9%: it is of the high-quality reservoir types in Dixi area. (3 The volcanic breccia reservoir has the same diagenetic features with sedimentary rocks, but also has the same mineral composition with volcanic rock; rigid components can keep the primary porosity without being affected by compaction during the burial process. At the same time, the brittleness of volcanic breccia reservoir makes it easily fracture under the stress; internal fracture was developmental. Volcanic breccia developed in the structural high part and suffered a long-term leaching effect. The original pore-fracture combination also made


    Edi Yatno


    Full Text Available Soils formed from volcanic materials have a high potential for agricultural development, especially for horticultural crops, tea, and pine trees. Data on the characteristics of these soils are important for the management planning. Six representative soil profiles developed on andesitic volcanic ash and tuff in Lembang area, West Java were studied to determine the soil physical, chemical, and mineralogical properties, to study the relationship between the soil properties, and to classify the soils according to the Soil Taxonomy. The results indicated that all the soils had very deep (>150 cm solum. In general, the volcanic ash soils were darker colored, more granular, more friable, less sticky and less plastic than the volcanic tuff soils. Physically, the ash soils had lower bulk density (0.44-0.73 mg m-3 and higher available water content (13-33% than the tuff soils. Bulk density decreased with increasing allophane. Chemically, the ash soils had higher pHNaF (mostly > 10, higher organic carbon (4.3-6.8% in upper horizons, higher CEC (20- 44 cmolc kg-1, and higher P retention (> 85% than the tuff soils. P retention logarithmically increased with increasing oxalate extractable Al and allophane. The sand fractions of the ash soils were dominated by hornblende, while the tuff soils were predominantly composed of opaque minerals. In the clay fractions, the ash soils were dominated by allophane, whereas the tuff soils showed high contents of gibbsite and metahalloysite. Soils developed on volcanic ash were classified as Thaptic Hapludands and Typic Melanudands, while soils formed from volcanic tuff were classified as Andic Dystrudepts. The low bulk density and friable consistency of the soils contributed to favorable soil tilth. However, high P retention and Al saturation in most soils are limiting factors for plant growth. Application of P fertilizers and liming coupled with efficient placement can be recommended to enhance P availability and

  5. Use of multiple in situ instruments and remote sensed satellite data for calibration tests at Solfatara (Campi Flegrei volcanic area)

    Silvestri, Malvina; Musacchio, Massimo; Fabrizia Buongiorno, Maria; Doumaz, Fawzi; Andres Diaz, Jorge


    Monitoring natural hazards such as active volcanoes requires specific instruments to measure many parameters (gas emissions, surface temperatures, surface deformation etc.) to determine the activity level of a volcano. Volcanoes in most cases present difficult and dangerous environment for scientists who need to take in situ measurements. Remote Sensing systems on board of satellite permit to measure a large number of parameters especially during the eruptive events but still show large limits to monitor volcanic precursors and phenomena at local scale (gas species emitted by fumarole or summit craters degassing plumes and surface thermal changes of few degrees) for their specific risk. For such reason unmanned aircraft systems (UAS) mounting a variety of multigas sensors instruments (such as miniature mass spectrometer) or single specie sensors (such as electrochemical and IR sensors) allow a safe monitoring of volcanic activities. With this technology, it is possible to perform monitoring measurements of volcanic activity without risking the lives of scientists and personnel performing analysis during the field campaigns in areas of high volcanic activity and supporting the calibration and validation of satellite data measurements. These systems allowed the acquisition of real-time information such as temperature, pressure, relative humidity, SO2, H2S, CO2 contained in degassing plume and fumaroles, with GPS geolocation. The acquired data are both stored in the sensor and transmitted to a computer for real time viewing information. Information in the form of 3D concentration maps can be returned. The equipment used during the campaigns at Solfatara Volcano (in 2014, 2015 and 2016) was miniaturized instruments allowed measurements conducted either by flying drones over the fumarolic sites and by hand carrying into the fumaroles. We present the results of the field campaign held in different years at the Solfatara of Pozzuoli, near Naples, concerning measurements

  6. Detection of ground deformation at the Neapolitan volcanic area (Southern Italy)

    Bottiglieri, M.; Falanga, M.; Tammaro, U.; de Martino, P.; Obrizzo, F.; Godano, C.; Pingue, F.


    The correct definition of the background level of ground deformation is a very important aspect in geodetic monitoring of volcanic areas. Indeed, it could allow a fast identification of an anomalous deformation trend that evolves towards an eruptive event. It is interesting confirm that any ground deformation modifies the distribution of the time series amplitude so significantly that this behaviour could be used as the marker of an effective source driven deformation. As an example, we analyse the site position time series of Neapolitan Volcanic Continuous GPS (NeVoCGPS) network operating on three volcanic active districts (Somma-Vesuvius volcano, Campi Flegrei Calder and Ischia Island) in a densely inhabited area, recorded during the period 2001-2007. These GPS time series reveal a very peculiar behaviour. When a clear deformation is observed, the amplitude distribution evolves from a gaussian to a bivariate gaussian distribution. This behaviour can be characterized by evaluating the kurtosis. The time series for all stations have been modelled with a fifth order polynomial fit. This represents the deformation history. Indeed, when this polynomial is subtracted from the time series, the distributions become again gaussian. A simulation of the deformation time evolution reveals that the amplitude distribution evolves towards a non gaussian behaviour if the ground deformation starts at 2/3 of the time series duration.

  7. Increased thyroid cancer incidence in a basaltic volcanic area is associated with non-anthropogenic pollution and biocontamination.

    Malandrino, Pasqualino; Russo, Marco; Ronchi, Anna; Minoia, Claudio; Cataldo, Daniela; Regalbuto, Concetto; Giordano, Carla; Attard, Marco; Squatrito, Sebastiano; Trimarchi, Francesco; Vigneri, Riccardo


    The increased thyroid cancer incidence in volcanic areas suggests an environmental effect of volcanic-originated carcinogens. To address this problem, we evaluated environmental pollution and biocontamination in a volcanic area of Sicily with increased thyroid cancer incidence. Thyroid cancer epidemiology was obtained from the Sicilian Regional Registry for Thyroid Cancer. Twenty-seven trace elements were measured by quadrupole mass spectrometry in the drinking water and lichens (to characterize environmental pollution) and in the urine of residents (to identify biocontamination) in the Mt. Etna volcanic area and in adjacent control areas. Thyroid cancer incidence was 18.5 and 9.6/10(5) inhabitants in the volcanic and the control areas, respectively. The increase was exclusively due to the papillary histotype. Compared with control areas, in the volcanic area many trace elements were increased in both drinking water and lichens, indicating both water and atmospheric pollution. Differences were greater for water. Additionally, in the urine of the residents of the volcanic area, the average levels of many trace elements were significantly increased, with values higher two-fold or more than in residents of the control area: cadmium (×2.1), mercury (×2.6), manganese (×3.0), palladium (×9.0), thallium (×2.0), uranium (×2.0), vanadium (×8.0), and tungsten (×2.4). Urine concentrations were significantly correlated with values in water but not in lichens. Our findings reveal a complex non-anthropogenic biocontamination with many trace elements in residents of an active volcanic area where thyroid cancer incidence is increased. The possible carcinogenic effect of these chemicals on the thyroid and other tissues cannot be excluded and should be investigated.

  8. Gas venting rates from submarine hydrothermal areas around the island of Milos, Hellenic Volcanic Arc

    Dando, P. R.; Hughes, J. A.; Leahy, Y.; Niven, S. J.; Taylor, L. J.; Smith, C.


    Gas seeps were located, by echo sounding, SCUBA divers and ROV observations, at hydrothermal sites around the island of Milos, in the Hellenic Volcanic Arc. Samples were collected by SCUBA divers and by a ROV from water depths between 3 and 110 m. Fifty-six flow rates from 39 individual seeps were measured and these ranged from 0.2 to 18.51 h -1 at the depth of collection. The major component, 54.9-91.9% of the gas, was carbon dioxide. Hydrogen (≤3%), methane (≤9.7%) and hydrogen sulphide (≤8.1%) were also measured. Hydrothermal free gas fluxes from the submarine hydrothermal areas around Milos were estimated to be greater than 10 10 moles y -1. It was concluded that submarine gas seeps along volcanic island arcs may be an important carbon dioxide source.

  9. Inversion of SAR data in active volcanic areas by optimization techniques

    G. Nunnari


    Full Text Available The inversion problem concerns the identification of parameters of a volcanic source causing observable changes in ground deformation data recorded in volcanic areas. In particular, this paper deals with the inversion of ground deformation measured by using SAR (Synthetic Aperture Radar interferometry and an inversion approach formulated in terms of an optimization problem is proposed. Based on this inversion scheme, it is shown that the problem of inverting ground deformation data in terms of a single source, of Mogi or Okada type, is numerically well conditioned. In the paper, two case studies of inverting actual SAR data recorded on Mt. Etna during eruptions occurring in 1998 and 2001 are investigated, showing the suitability of the proposed technique.

  10. Attenuation of short period seismic waves at Etna as compared to other volcanic areas

    Del Pezzo, E.; Gresta, S.; Patané, G.; Patané, D.; Scarcella, G.


    Coda Q for Etna volcano is frequency dependent and the Q frequency pattern and the numerical values ranging from about 100 at 1 Hz to about 300 at 18 Hz are similar to the values obtained for other volcanoes: Campi Flegrei, Aeolian Islands and Hawaii. Moreover the frequency pattern and the numerical values of coda quality factor, for most of the seismically active zones of Italy are very different from those of the volcanic zones. Several studies of the location of magma chambers show the presence of magma pockets beneath Lipari and Vulcano Islands of the Aeolian archipelago and an anomalous low velocity body beneath Etna. These evidences suggest that a possible interpretation of the characteristic frequency pattern of Q on volcanic areas is that the presence of magma can modify the scattering environment and consequently the coda Q estimates.

  11. Carbon and Noble Gas Isotopes in the Tengchong Volcanic Geothermal Area, Yunnan, Southwestern China

    XU Sheng; Shun'ich NAKAI; Hiroshi WAKITA; WANG Xianbin


    Carbon and noble gas isotope analyses are reported for bubbling gas samples from the Tengchong volcanic geothermal area near the Indo-Eurasian suture zone. All samples contain a resolvable component of mantle-derived 3He.Occurrence of mantle-derived 3He coincides with surface volcanism. However, 3He occurs over a larger geographic area than do surface volcanics. δ13C values for CO2 and CH4 vary from -33.4 ‰ to 1.6 ‰ and from -52.8 ‰ to -2.8 ‰,respectively. He and C isotope systematics indicate that CO2 and CH4 in the CO2-rich gases originated predominantly from magmatic component mixed with crustal CO2 produced from carbonate. However, breakdown of organic matter and nearsurface processes accounts for the CH4 and CO2 in N2-rich gases. 3He/4He ratio distribution pattern suggests that mantlederived He and heat sources of high-temperature system in central Tengchong originate from a hidden magma reservoir at subsurface. CO2-rich gases with the highest 3He/4He ratio (5.2 Ra) may be representative of the Tengchong magmatic component. Compared with MORB, this relative low 3He/4He ratio could be fully attributed to either deep crustal contamination, or radioactive aging, or past contamination of the local mantle by U- and Th-rich subducted crustal material.However, a combination of low 3He/4He, high radiogenic 4He/40Ar ratio and identical CO2/3He and δ13Cco2 relative to MORB may suggest addition of prior subductedd crsustal material (ca 1%-2%) to the MORB reservoir around 1.3 Ga ago,which is essentially compatible with the LIL-elements, and Sr-Nd-Pb isotopes of volcanic rocks.

  12. Subsurface Contamination Focus Area technical requirements. Volume 1: Requirements summary

    Nickelson, D.; Nonte, J.; Richardson, J.


    This document summarizes functions and requirements for remediation of source term and plume sites identified by the Subsurface Contamination Focus Area. Included are detailed requirements and supporting information for source term and plume containment, stabilization, retrieval, and selective retrieval remedial activities. This information will be useful both to the decision-makers within the Subsurface Contamination Focus Area (SCFA) and to the technology providers who are developing and demonstrating technologies and systems. Requirements are often expressed as graphs or charts, which reflect the site-specific nature of the functions that must be performed. Many of the tradeoff studies associated with cost savings are identified in the text.

  13. Surface deformation of active volcanic areas retrieved with the SBAS-DInSAR technique: an overview

    G. Zeni


    Full Text Available This paper presents a comprehensive overview of the surface deformation retrieval capability of the Differential Synthetic Aperture Radar Interferometry (DInSAR algorithm, referred to as Small BAseline Subset (SBAS technique, in the context of active volcanic areas. In particular, after a brief description of the algorithm some experiments relevant to three selected case-study areas are presented. First, we concentrate on the application of the SBAS algorithm to a single-orbit scenario, thus considering a set of SAR data composed by images acquired on descending orbits by the European Remote Sensing (ERS radar sensors and relevant to the Long Valley caldera (eastern California area. Subsequently, we address the capability of the SBAS technique in a multipleorbit context by referring to Mt. Etna volcano (southern Italy test site, with respect to which two different ERS data set, composed by images acquired both on ascending and descending orbits, are available. Finally, we take advantage of the capability of the algorithm to work in a multi-platform scenario by jointly exploiting two different sets of SAR images collected by the ERS and the Environment Satellite (ENVISAT radar sensors in the Campi Flegrei caldera (southern Italy area. The presented results demonstrate the effectiveness of the algorithm to investigate the deformation field in active volcanic areas and the potential of the DInSAR methodologies within routine surveillance scenario.

  14. Cenozoic volcanism and lithospheric tectonic evolution in Qiangtang area, northern Qinghai-Tibet Plateau

    CHI Xiaoguo; LI Cai; JIN Wei


    Following the collision between the Indian and Eurasian plates, the Cenozoic volcanic activities are rather frequent in the Qiangtang area of northern Qinghai-Tibet Plateau. They can be divided into four series: alkaline basalt series, high-K calc-alkaline series, shoshonitic series and peralkaline potassic-ultrapotassic series. Geochemical data suggest that the magma sources of Cenozoic volcanic rocks have transferred from spinel Iherzolite mantle in the early stage to garnet peridotite enriched mantle (EM2) in the later stage. The high Mg# number and extremely high Cr-Ni-Co abundance of high-K calc-alkaline and shoshonitic series andesites in the Qiangtang area indicate that the primary magma might be derived from subduction of continent lithosphere from the Lhasa block. Incompatible element ratios of La/Rb, Zr/Rb, Rb/Nb, K/Nb,Pb/La and K/La of peralkaline potassic-ultrapotassic series lavas in northern Qinghai-Tibet Plateau are lower than island arc volcanic rocks and higher than and similar to oceanic island basalts. This signature indicates that the primary magma derive from a paleo-mantle wedge interfused by fluids derived from asthenosphere and/or subducted mantle lithosphere. But the above element ratios of ultrapotassic lavas in southern Tibet and ultrapotassic lamprophyres in eastern Tibet are higher than and similar to island arc volcanic rocks, which means that the primary magma sources contained a large quantity of crust contaminant from fluids and/or melts derived from subducted continent lithosphere. The studies result supports that the indian continental .lithosphere has underthrust beneath Tibet to about the middle of the plateau, and Eurasian (Qaidam basin) mantle lithosphere has underthrust beneath the Qiangtang area of northern Tibet Plateau. In the paper we demonstrate further that the pulsing cycles of potassic-ultrapotassic volcanism of the Qinghai-Tibet Plateau result from an asthenospher pulsing upwelling caused by the intraplate subduction

  15. Spatial Characteristics of Geothermal Spring Temperatures and Discharge Rates in the Tatun Volcanic Area, Taiwan

    Jang, C. S.; Liu, C. W.


    The Tatun volcanic area is the only potential volcanic geothermal region in the Taiwan island, and abundant in hot spring resources owing to stream water mixing with fumarolic gases. According to the Meinzer's classification, spring temperatures and discharge rates are the most important properties for characterizing spring classifications. This study attempted to spatially characterize spring temperatures and discharge rates in the Tatun volcanic area, Taiwanusing indicator kriging (IK). First, data on spring temperatures and discharge rates, which were collected from surveyed data of the Taipei City Government, were divided into high, moderate and low categories according to spring classification criteria, and the various categories were regarded as estimation thresholds. Then, IK was adopted to model occurrence probabilities of specified temperatures and discharge rates in springs, and to determine their classifications based on estimated probabilities. Finally, nine combinations were obtained from the classifications of temperatures and discharge rates in springs. Moreover, the combinations and features of spring water were spatially quantified according to seven sub-zones of spring utilization. A suitable and sustainable development strategy of the spring area was proposed in each sub-zone based on probability-based combinations and features of spring water.The research results reveal that the probability-based classifications using IK provide an excellent insight in exploring the uncertainty of spatial features in springs, and can provide Taiwanese government administrators with detailed information on sustainable spring utilization and conservation in the overexploited spring tourism areas. The sub-zones BT (Beitou), RXY (Rd. Xingyi), ZSL (Zhongshanlou) and LSK (Lengshuikeng) with high or moderate discharge rates are suitable to supply spring water for tourism hotels.Local natural hot springs should be planned in the sub-zones DBT (Dingbeitou), ZSL, XYK

  16. Geochemistry and tectonic setting of Tertiary volcanism in the Güvem area, Anatolia, Turkey

    Tankut, Ayla; Wilson, Marjorie; Yihunie, Tadesse


    Detailed field mapping in the Güvem area in the Galatia province of NW Central Anatolia, Turkey, combined with K-Ar dating, has established the existence of two discrete Miocene volcanic phases, separated by a major unconformity. The magmas were erupted in a post-collisional tectonic setting and it is possible that the younger phase could be geodynamically linked to the onset of transtensional tectonics along the North Anatolian Fault zone. The Early Miocene phase (18-20 Ma; Burdigalian) is the most voluminous, comprising of over 1500 m of potassium-rich intermediate-acid magmas. In contrast, the Late Miocene volcanic phase (ca. 10 Ma; Tortonian) comprises a single 70-m-thick flow unit of alkali basalt. The major and trace element and Sr-Nd isotope compositions of the volcanics suggest that the Late Miocene basalts and the parental mafic magmas to the Early Miocene series were derived from different mantle sources. Despite showing some similarities to high-K calc-alkaline magma series from active continental margins, the Early Miocene volcanics are clearly alkaline with higher abundances of high field strength elements (Zr, Nb, Ti, Y). Crustal contamination appears to have enhanced the effects of crystal fractionation in the petrogensis of this series and some of the most silica-rich magmas may be crustal melts. The mantle source of the most primitive mafic magmas is considered to have been an asthenospheric mantle wedge modified by crustally-derived fluids rising from a Late Cretaceous-Early Tertiary Tethyan subduction zone dipping northwards beneath the Galatia province. The Late Miocene basalts, whilst still alkaline, have a Sr-Nd isotope composition indicating partial melting of a more depleted mantle source component, which most likely represents the average composition of the asthenosphere beneath the region.

  17. Mantle xenoliths from Marosticano area (Northern Italy): a comparison with Veneto Volcanic Province lithospheric mantle

    Brombin, Valentina; Bonadiman, Costanza; Coltorti, Massimo


    The Tertiary Magmatic Province of Veneto, known as Veneto Volcanic Province (VVP), in the North-East of Italy, represents the most important volcanic distric of Adria Plate. It is composed by five volcanic bodies: Val d'Adige, Marosticano, Mts. Lessini, Berici Hills and Euganean Hills. Most of the volcanic products are relatively undifferentiated lavas and range in composition from nephelinites to tholeiites. Often VVP nephelinites and basanites carry mantle xenoliths (mainly harzburgites and lherzolite). This study reports petrological comparison between Marosticano xenoliths (new outcrop) and xenoliths from the Lessinean and Val d'Adige areas already studied by many Authors (Siena & Coltorti 1989; Beccaluva et al., 2001, Gasperini et al., 2006). Mineral major elements analyses show that the Marosticano lherzolites and harzburgites reflect "more restitic" composition than the mantle domain beneath the other VVP districts (Lessini Mts. and Val d'Adige). In fact, olivine and pyroxene of Marosticano xenoliths have the highest mg# values of the entire district (Marosticano→90-93; literature→86-92). At comparable mg# (45-85 wt%) Marosticano spinels tend to be higher in Cr2O3 (23-44 wt%) contents with respect to the other VVP sp (7-25 wt%). It is worth noting that, Ni contents of Marosticano olivines in both harzburgites and lherzolites are higher (2650-3620 ppm) than those of the Lessinean xenoliths (1500- 3450 ppm), and similar to that of Val d'Adige lherzolites (3000-3500 ppm), approaching the contents of Archean cratonic mantle (Kelemen, 1998). In turn, Lessinean olivines properly fall in the Ni-mg# Phanerozoic field. At fixed pressure of 15 kbar, the equilibration temperature of Marosticano xenoliths are similar (Brey & Köhler: 920-1120°C) to those of Lessini (O'Neill & Wall: 990-1110°C; Beccaluva et al., 2007), but higher than those of Val d'Adige (Wells: 909-956°C; Gasperini et al., 2006). Finally, Marosticano mantle fragment show similar relatively high

  18. Self-potential, geoelectric and magnetotelluric studies in Italian active volcanic areas

    A. Siniscalchi


    Full Text Available We present the results of self-potential, geoelectric and magnetotelluric studies in Italian active volcanic areas as essential contributions both to structural modeling and to hazard evaluation. On Mt. Etna and Mt. Somma-Vesuvius complexes structural modeling was emphasized due to a lack of global information involving the whole apparatuses, at least from the electrical point of view. Hazard investigation was, instead, investigated with high resolution techniques on the island of Vulcano, where intense unrest phenomena have long been recorded.

  19. Late Cenozoic volcanism in the western Woodlark Basin area, SW Pacific: the sources of marine volcanic ash layers based on their elemental and Sr-Nd isotope compositions

    Lackschewitz, K. S.; Mertz, D. F.; Devey, C. W.; Garbe-Schönberg, C.-D.


    Tephra fallout layers and volcaniclastic deposits, derived from volcanic sources around and on the Papuan Peninsula, form a substantial part of the Woodlark Basin marine sedimentary succession. Sampling by the Ocean Drilling Program Leg 180 in the western Woodlark Basin provides the opportunity to document the distribution of the volcanically-derived components as well as to evaluate their chronology, chemistry, and isotope compositions in order to gain information on the volcanic sources and original magmatic systems. Glass shards selected from 57 volcanogenic layers within the sampled Pliocene-Pleistocene sedimentary sequence show predominantly rhyolitic compositions, with subordinate basaltic andesites, basaltic trachy-andesites, andesites, trachy-andesites, dacites, and phonolites. It was possible to correlate only a few of the volcanogenic layers between sites using geochemical and age information apparently because of the formation of strongly compartmentalised sedimentary realms on this actively rifting margin. In many cases it was possible to correlate Leg 180 volcanic components with their eruption source areas based on chemical and isotope compositions. Likely sources for a considerable number of the volcanogenic deposits are Moresby and Dawson Strait volcanoes (D'Entrecasteaux Islands region) for high-K calc-alkaline glasses. The Dawson Strait volcanoes appear to represent the source for five peralkaline tephra layers. One basaltic andesitic volcaniclastic layer shows affinities to basaltic andesites from the Woodlark spreading tip and Cheshire Seamount. For other layers, a clear identification of the sources proved impossible, although their isotope and chemical signatures suggest similarities to south-west Pacific subduction volcanism, e.g. New Britain and Tonga-Kermadec island arcs. Volcanic islands in the Trobriand Arc (for example, Woodlark Island Amphlett Islands and/or Egum Atoll) are probable sources for several volcaniclastic layers with ages

  20. Remote sensing and GIS study of an eroded Miocene volcanic area (Hegau, SW Germany)

    Strehlau, J.; Theilen-Willige, B.


    Remote sensing techniques offer useful tools that can aid in evaluating the geomorphologic and geologic evolution of eroded volcanic landforms. Erosion provides insight into subsurface structural levels of a volcanic edifice, but it is difficult to correctly interpret the field observations, particularly if the exposed landforms have been modified by tectonic and fluvioglacial processes. An illustrative example is the Hegau volcanic field, located NW of Lake Constance near the northern margin of the Molasse Basin in the Alpine foreland (e.g., Schreiner, Samml. Geol. Führer 62, 2008). This region, situated on the periphery of the Upper Cretaceous-Quaternary mafic alkaline magmatic province in central Europe (e.g., Blusztajn and Hegner, Chem. Geol. 2002), was episodically active during the Miocene; K-Ar age determinations (mostly obtained in the 1960/70s) indicate emplacement ages ranging from about 15-7 Ma. Several eroded plugs and necks of olivine melilites and phonolites form prominent landmarks rising above the present-day Hegau landscape. The area also contains remnants of dikes, maar crater lakes, basalt flows, travertine and pyroclastic deposits (both pipe-filling and eruptive tuff sheets). The volcanic constructs were largely buried by Molasse sediments, due to continued flexural subsidence of the foreland lithosphere during the Tertiary. Since the cessation of the Molasse phase, the region has undergone exhumation and erosion of up to several hundred meters (increasing towards the Alpine front) as indicated by reconstructions of missing stratigraphic sections based on borehole studies (references in Rahn and Selbekk, Swiss J. Geosci. 2007). Pleistocene ice sheets repeatedly covered parts of the area and deposited moraines, gravel plains, and lake deposits (e.g., Fiebig and Preusser, Geograph. Helv. 2008). Furthermore, deep fluvioglacial valleys were carved out that were sequentially re-filled and partly re-eroded, resulting in a system of narrow basins and

  1. Utilizing NASA Earth Observations to Model Volcanic Hazard Risk Levels in Areas Surrounding the Copahue Volcano in the Andes Mountains

    Keith, A. M.; Weigel, A. M.; Rivas, J.


    Copahue is a stratovolcano located along the rim of the Caviahue Caldera near the Chile-Argentina border in the Andes Mountain Range. There are several small towns located in proximity of the volcano with the two largest being Banos Copahue and Caviahue. During its eruptive history, it has produced numerous lava flows, pyroclastic flows, ash deposits, and lahars. This isolated region has steep topography and little vegetation, rendering it poorly monitored. The need to model volcanic hazard risk has been reinforced by recent volcanic activity that intermittently released several ash plumes from December 2012 through May 2013. Exposure to volcanic ash is currently the main threat for the surrounding populations as the volcano becomes more active. The goal of this project was to study Copahue and determine areas that have the highest potential of being affected in the event of an eruption. Remote sensing techniques were used to examine and identify volcanic activity and areas vulnerable to experiencing volcanic hazards including volcanic ash, SO2 gas, lava flow, pyroclastic density currents and lahars. Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI), EO-1 Advanced Land Imager (ALI), Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topography Mission (SRTM), ISS ISERV Pathfinder, and Aura Ozone Monitoring Instrument (OMI) products were used to analyze volcanic hazards. These datasets were used to create a historic lava flow map of the Copahue volcano by identifying historic lava flows, tephra, and lahars both visually and spectrally. Additionally, a volcanic risk and hazard map for the surrounding area was created by modeling the possible extent of ash fallout, lahars, lava flow, and pyroclastic density currents (PDC) for future eruptions. These model results were then used to identify areas that should be prioritized for disaster relief and evacuation orders.

  2. Supracrustal rocks in the Kuovila area, Southern Finland: structural evolution, geochemical characteristics and the age of volcanism

    Pietari Skyttä; Asko Käpyaho; Irmeli Mänttäri


    The supracrustal rocks of the Kuovila area in the Palaeoproterozoic Svecofennian Uusimaa Belt, southern Finland, consist mainly of volcaniclastic rocks associated with banded iron formations (BIFs) and marbles. Small ZnS and PbS mineralizations are occasionally located within the marbles. Some primary features are well preserved in the sedimentary and volcanic rocks, including lamination in tuffites and banded iron formations. Geochemical results show that the volcanism was bimodal and it mai...

  3. Potential and limitations of risk scenario tools in volcanic areas through an example at Mount Cameroon

    P. Gehl


    Full Text Available This paper presents an integrated approach to conduct a scenario-based volcanic risk assessment on a variety of exposed assets, such as residential buildings, cultivated areas, network infrastructures or individual strategic buildings. The focus is put on the simulation of scenarios, based on deterministic adverse event input, which are applied to the case study of an effusive eruption on the Mount Cameroon volcano, resulting in the damage estimation of the assets located in the area. The work is based on the recent advances in the field of seismic risk. A software for systemic risk scenario analysis developed within the FP7 project SYNER-G has been adapted to address the issue of volcanic risk. Most significant improvements include the addition of vulnerability models adapted to each kind of exposed element and the possibility to quantify the successive potential damages inflicted by a sequence of adverse events (e.g. lava flows, tephra fall, etc.. The use of an object-oriented architecture gives the opportunity to model and compute the physical damage of very disparate types of infrastructures under the same framework. Finally, while the risk scenario approach is limited to the assessment of the physical impact of adverse events, a specific focus on strategic infrastructures and a dialogue with stakeholders helps in evaluating the potential wider indirect consequences of an eruption.

  4. Determination of ancient volcanic eruption center based on gravity methods (3D) in Gunungkidul area Yogyakarta, Indonesia

    Santoso, Agus; Sismanto, Setiawan, Ary; Pramumijoyo, Subagyo


    Ancient eruption centers can be determined by detecting the position of the ancient volcanic material, it is important to understand the elements of ancient volcanic material by studying the area geologically and prove the existence of an ancient volcanic eruption centers using geophysics gravity method. The measuring instrument is Lacoste & Romberg gravimeter type 1115, the number of data are 900 points. The area 60×40 kilometers, the modeling 3D software is reaching depth of 15 km at the south of the island of Java subduction zone. It is suported by geological data in the field that are found as the following: 1. Pyroclastic Fall which is a product of volcanic eruptions, and lapilli tuff with felsic mineral. 2. Pyroclastic flow with Breccia, tuffaceous sandstone and tuff breccia. 3. Hot springs near Parangwedang Parangtritis. 4. Igneous rock with scoria structure in Parang Kusumo, structured amigdaloida which is the result of the eruption of lava/volcanic eruptions, and Pillow lava in the shows the flowing lava into the sea. Base on gravity anomaly shows that there are strong correlationship between those geological data to the gravity anomaly. The gravblox modeling (3D) shows the position of ancient of volcanic eruption in this area clearly.

  5. Three-dimensional seismic velocity tomography of the upper crust in Tengchong volcanic area, Yunnan Province

    楼海; 王椿镛; 皇甫岗; 秦嘉政


    Based on data collected by deep seismic sounding carried out in 1999, a three-dimensional P wave velocity structure is determined with tomographic inversion. The tomographic result shows that there is a P wave low velocity zone (LVZ) in the upper crust beneath the Tengchong volcanic area. The LVZ is in the depth of 7~8 km and may be a small magma chamber or a partial melting body. The result also shows that the LVZ is in the northeastern side of the Rehai hydrothermal field, which is located in another LVZ near the surface. The shallow LVZ may represent a well-developed fracture zone. The strong hydrothermal activity in Rehai area can attribute to the existence of fractures between two LVZs. These fractures are the channels for going upwards of the deep hot fluid.

  6. Basic-ultrabasic and volcanic rocks in Chagbu-Shuanghu area of northern Xizang (Tibet),China

    邓万明; 尹集祥; 呙中平


    The widespread Early Permian and Triassic sequences outcropping in the Chagbu-Shuanghu area of northern Xizang, China, are mainly characterized by volcanic rocks belonging to tholeiite with subordinate veins of diallagite. wehrlite and limburgites schlierens. These ultrabasic rocks do not carry plastic deformational fabrics from upper mantle and may result from the crystallization of fused mass derived from mantle under condition of deeper crust or earlier segregation of tholeiitic magma. These volcanic rocks, as interlayers or lens, are generally involved in slates, limestones and pebbly slates or breccia and geochemically different from MORB. It is reasonable to conclude from research results that the volcanic activities during the Early Permian and Late Triassic would be able to occur in an intraplale environment suffering initial extension of continental crust or an aulacogen. Therefore, these basic-ultrabasic and volcanic rocks did not constitute an ophiolitic association with an occurrence 6f the

  7. Petro-chemical features and source areas of volcanic aggregates used in ancient Roman maritime concretes

    Marra, F.; Anzidei, M.; Benini, A.; D'Ambrosio, E.; Gaeta, M.; Ventura, G.; Cavallo, A.


    We present and discuss data from petrographic observation at the optical microscope, electron microprobe analyses on selected glass shards, and trace-element analyses on 14 mortar aggregates collected at the ancient harbors and other maritime structures of Latium and Campania, spanning the third century BCE through the second CE, aimed at identify the volcanic products employed in the concretes and their area of exploitation. According to Latin author Vitruvius assertion about the ubiquitous use of Campanian pozzolan in the ancient Roman sea-water concretes, results of this study show a very selective and homogeneous choice in the material employed to produce the concretes for the different investigated maritime structures, evidencing three main pumice compositions, all corresponding to those of the products of the post-Neapolitan Yellow Tuff activity of the Phlegraean Fields, and a systematic use of the local Neapolitan Yellow Tuff to produce the coarse aggregate of these concretes. However, mixing with local products of the Colli Albani volcanic district, located 20 km east of Rome, has been evidenced at two fishponds of Latium, in Punta della Vipera and Torre Astura. Based on these petrographic and geochemical data, we conclude that the selective use of pozzolan from Campania, rather than of unproved different chemical properties, was the consequence of a series of logistic, economic, industrial and historical reasons.

  8. Seafloor doming driven by degassing processes unveils sprouting volcanism in coastal areas

    Passaro, Salvatore; Tamburrino, Stella; Vallefuoco, Mattia; Tassi, Franco; Vaselli, Orlando; Giannini, Luciano; Chiodini, Giovanni; Caliro, Stefano; Sacchi, Marco; Rizzo, Andrea Luca; Ventura, Guido


    We report evidences of active seabed doming and gas discharge few kilometers offshore from the Naples harbor (Italy). Pockmarks, mounds, and craters characterize the seabed. These morphologies represent the top of shallow crustal structures including pagodas, faults and folds affecting the present-day seabed. They record upraise, pressurization, and release of He and CO2 from mantle melts and decarbonation reactions of crustal rocks. These gases are likely similar to those that feed the hydrothermal systems of the Ischia, Campi Flegrei and Somma-Vesuvius active volcanoes, suggesting the occurrence of a mantle source variously mixed to crustal fluids beneath the Gulf of Naples. The seafloor swelling and breaching by gas upraising and pressurization processes require overpressures in the order of 2-3 MPa. Seabed doming, faulting, and gas discharge are manifestations of non-volcanic unrests potentially preluding submarine eruptions and/or hydrothermal explosions.

  9. Mid-Miocene Silicic Volcanism of the Three Fingers - Mahogany Mountain Area, SE Oregon - Revisited

    Marcy, P.; Streck, M. J.; Ferns, M.


    Earlier work identified two adjacent caldera systems, the Mahogany Mountain and Three Fingers calderas as the centerpiece of voluminous rhyolitic volcanism on the eastern margin of the Oregon-Idaho graben during the mid-Miocene. Silicic volcanism of Three Fingers-Mahogany Mtn. area is part of the Lake Owyhee volcanic field, Oregon and belongs to widespread rhyolites associated with the Columbia River Basalt province. Here we revisit field evidence and establish relationships between intra-caldera units of Three Fingers and Mahogany Mtn. calderas, and their outflow facies, the tuffs of Spring Creek and Leslie Gulch. In addition, we assess the distribution of entrained mafic clasts and their often anomalously high, nearly ore-grade concentrations of rare earth elements (REE). Previous mapping identified two groups of intra-caldera rhyolite units: 1) intra-caldera tuffs of Spring Creek and Leslie Gulch and 2) younger rhyolite lavas (Trp) within Three Fingers Caldera and cross-cutting rhyolite dikes within the core of Mahogany Mtn. Caldera. Our mapping determines that devitrified Trp of Three Fingers area is equivalent to surrounding often glassy, pumiceous to dense or brecciated rhyolite flows mapped before as intra-caldera tuff of Spring Creek, and all are compositionally indistinguishable from cross-cutting dikes within Mahogany Mtn. Reinterpreted rhyolites of Three Fingers Caldera lack vitroclastic textures and are geochemically distinct from outflow tuff of Spring Creek which in turn can be distinguished from the tuff of Leslie Gulch. Outflow tuff of Spring Creek is Fe-rich, low silica rhyolite (~74 wt.% SiO2, 3 wt.% FeO, ~1600 ppm Ba) as compared to less Fe rich, high-silica rhyolite (~77 wt.% SiO2, 2 wt.% FeO, ~200 ppm Ba) of intra-caldera units. Outflow tuff of Leslie Gulch is also high-silica rhyolite but Ba rich (~1500 ppm). We interpret the investigated Three Fingers area as a rhyolite dome field, erupting subsequent to caldera collapse. There, abundant post

  10. Supracrustal rocks in the Kuovila area, Southern Finland: structural evolution, geochemical characteristics and the age of volcanism

    Pietari Skyttä


    Full Text Available The supracrustal rocks of the Kuovila area in the Palaeoproterozoic Svecofennian Uusimaa Belt, southern Finland, consist mainly of volcaniclastic rocks associated with banded iron formations (BIFs and marbles. Small ZnS and PbS mineralizations are occasionally located within the marbles. Some primary features are well preserved in the sedimentary and volcanic rocks, including lamination in tuffites and banded iron formations. Geochemical results show that the volcanism was bimodal and it mainly had volcanic arc affinity. Specific geochemical indicators suggesting a volcanic arc origin for the Kuovila volcanic rocks include: 1 Enrichment of LILE over the HFSE elements and 2 Distinctly low Nb and Ta contents in relation to Th, Ce and LREE. Geochemistry of the Kuovila area volcanic rocks is very similar to those of the Orijärvi and Kisko formations, located ~15 km NE of Kuovila. Felsic tuff in the Kuovila area was dated at 1891±4 Ma by the U-Pb system on zircons. Consequently volcanism was contemporaneous with magmatism in the adjacent Orijärvi area, thus representing the earliest identified volcanic stage in the southern Svecofennian Uusimaa Belt. Early deformation structures within the Kuovila area are suggested to relate to low-metamorphic or localized low-angle thrusting during D1. F1 folds were recumbent and the S1 cleavages are generally weak. Thrusting was followed by approximately N–S contraction with upright, peak-metamorphic F2 folding overprinting D1 structures and defining the Kuovila synform. Two separate intrusive phases include a synvolcanic granodiorite-diorite-gabbro association and a weakly S2-foliated syn-D2 granodiorite. Anatectic granites and associated migmatizing veins are absent, therefore suggesting that D2 pre-dates the ~1.84–1.82 Ga metamorphic event in the Southern Svecofennian Arc Complex (SSAC. D2 structuresin the Kuovila area are suggested to correlate with the early structures with associated axial planar

  11. A method for multi-hazard mapping in poorly known volcanic areas: an example from Kanlaon (Philippines

    M. Neri


    Full Text Available Hazard mapping in poorly known volcanic areas is complex since much evidence of volcanic and non-volcanic hazards is often hidden by vegetation and alteration. In this paper, we propose a semi-quantitative method based on hazard event tree and multi-hazard map constructions developed in the frame of the FP7 MIAVITA project. We applied this method to the Kanlaon volcano (Philippines, which is characterized by poor geologic and historical records. We combine updated geological (long-term and historical (short-term data, building an event tree for the main types of hazardous events at Kanlaon and their potential frequencies. We then propose an updated multi-hazard map for Kanlaon, which may serve as a working base map in the case of future unrest. The obtained results extend the information already contained in previous volcanic hazard maps of Kanlaon, highlighting (i an extensive, potentially active ~5 km long summit area striking north–south, (ii new morphological features on the eastern flank of the volcano, prone to receiving volcanic products expanding from the summit, and (iii important riverbeds that may potentially accumulate devastating mudflows. This preliminary study constitutes a basis that may help local civil defence authorities in making more informed land use planning decisions and in anticipating future risk/hazards at Kanlaon. This multi-hazard mapping method may also be applied to other poorly known active volcanoes.

  12. Case Study of Volcanic Rock Reservoir--Beibao Area of Nanbao Sag

    Guo Qijun; Wan Zhimin; Jiao Shouquan; Liu Laixiang


    @@ Preface Crude has been produced from volcanic rock reservoirs inAmerica, Libya, Indonesia and Japan, according to the available data. Oil and gas Production from volcanic rock reservoirs in Japan accounts for 30% of the total, with the recoverable reserves estimated at 48% of the total. Oil and gas traps of volcanic rock reservoir with better reservoir properties and flow potential have been discovered in Liaohe, Erlian, Jizhong, Huanghua, Jiyang, Linqing,Jiangsu and Xinjiang of China since the 1970's. However,the systematic study of volcanic rock reservoir is just in the beginning.

  13. Structural control on geothermal circulation in the Tocomar geothermal volcanic area (Puna plateau, Argentina)

    Giordano, Guido


    The reconstruction of the stratigraphical-structural framework and the hydrogeology of geothermal areas is fundamental for understanding the relationships between cap rocks, reservoir and circulation of geothermal fluids and for planning the exploitation of the field. The Tocomar geothermal volcanic area (Puna plateau, Central Andes, NW Argentina) has a high geothermal potential. It is crossed by the active NW-SE trans-Andean tectonic lineament known as the Calama-Olacapato-Toro (COT) fault system, which favours a high secondary permeability testified by the presence of numerous thermal springs. This study presents new stratigraphic, structural, volcanological, geochemical and hydrogeological data on the geothermal field. Our data suggest that the main geothermal reservoir is located within or below the Pre-Palaeozoic-Ordovician basement units, characterised by unevenly distributed secondary permeability. The reservoir is recharged by infiltration in the ridges above 4500 m a.s.l., where basement rocks are in outcrop. Below 4500 m a.s.l., the reservoir is covered by the low permeable Miocene-Quaternary units that allow a poor circulation of shallow groundwater. Geothermal fluids upwell in areas with more intense fracturing, especially where main regional structures, particularly NW-SE COT-parallel lineaments, intersect with secondary structures, such as at the Tocomar field.

  14. Geology and geochemistry characteristics of the Chiapanecan Volcanic Arc (Central Area), Chiapas Mexico

    Mora, J. C.; Jaimes-Viera, M. C.; Garduño-Monroy, V. H.; Layer, P. W.; Pompa-Mera, V.; Godinez, M. L.


    The Chiapanecan Volcanic Arc (CVA), located in the central portion of the State of Chiapas, is a 150 km stretch of volcanoes irregularly aligned in the northwest direction between two great volcanic features: the Trans-Mexican Volcanic Belt to the northwest and the Central American Volcanic Arc to the southeast. The CVA is located in a complex zone marking the interaction of the North American, Caribbean and Cocos plates, near the Motagua-Polochic fault system, the boundary between North American and Caribbean plates. The central part of the CVA is composed of an irregular northwest alignment of at least 10 volcanic structures generally lying along NNW-SSE-trending faults splayed from the Motagua-Polochic system. Among the structures there are seven volcanic domes (Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza and Santotón), one explosion crater (Navenchauc), one collapse structure (Apas), and one dome complex (Tzontehuitz). In the majority of the structures there is a clear resurgence with the formation of several domes in the same structure, with the destruction of previous domes (Navenchauc) or with the formation of new explosion craters or collapse structures (Apas). The volcanic activity in the CVA was mainly effusive accompanied by explosive and phreatomagmatic events and is characterized by volcanic domes accompanied by block-and-ash-flows, ash flows with accretionary lapilli, falls, and pumice flows. The volcanic structures and deposits are calcalkaline in composition with a medium to high content of potassium. CVA volcanic rocks vary from andesite to dacite with SiO 2 between 57 and 66 wt.%, show low concentrations of Ti, P, Nb and Ta, are enriched in Light Rare Earths, depleted in Heavy Rare Earths, and show a small Eu anomaly; all indicative of arc-related volcanism associated with subduction of the Cocos plate under the North American plate, but complicated by the geometry of the plate boundary fault system.

  15. Strategies in the processing and analysis of continuous gravity record in active volcanic areas: the case of Mt. Vesuvius

    J. Hinderer


    Full Text Available This research is intended to describe new strategies in the processing and analysis of continuous gravity records collected in active volcanic areas and to assess how permanent gravity stations can improve the geophysical monitoring of a volcano. The experience of 15 years in continuous gravity monitoring on Mt. Vesuvius is discussed. Several geodynamic phenomena can produce temporal gravity changes. An eruption, for instance, is associated with the ascent of magma producing changes in the density distribution at depth, and leading to ground deformation and gravity changes The amplitude of such gravity variations is often quite small, in the order of 10-102 nms-2, so their detection requires high quality data and a rigorous procedure to isolate from the records those weak gravity signals coming from different sources. Ideally we need gravity signals free of all effects which are not of volcanic origin. Therefore solid Earth tide, ocean and atmospheric loading, instrumental drift or any kind of disturbances other than due to the volcano dynamics have to be removed. The state of the art on the modelling of the solid Earth tide is reviewed. The atmospheric dynamics is one of the main sources precluding the detection of small gravity signals. The most advanced methods to reduce the atmospheric effects on gravity are presented. As the variations of the calibration factors can prevent the repeatability of high-precision measurements, new approaches to model the instrumental response of mechanical gravimeters are proposed too. Moreover, a strategy for an accurate modelling of the instrumental drift and to distinguish it from longterm gravity changes is suggested.

  16. Monitoring of low-energy seismic activity in Elbrus volcanic area with the use of underground seismic array

    Kovalevsky, V.; Sobisevitch, A.


    Results of experiment with underground seismic array for studying low-energy seismic activity in the Elbrus volcanic area are presented. Linear seismic array of 2.5 km aperture is created in the tunnel of Baksan neutrino observatory. Horizontal tunnel of 4.3 km length is drilled in the mount Andyrchi at a distance of 20 km from Elbrus volcano. Array includes 6 three-component seismic sensors with 24-byte recorders installed with 500 m interval one from another along the tunnel. Underground seismic array is the new instrument of geophysical observatory organized for studies of geophysical processes in the Elbrus volcanic area. The observatory equipped with modern geophysical instruments including broadband tri-axial seismometers, quartz tilt-meters, magnetic variometers, geo-acoustic sensors, hi-precision distributed thermal sensors and gravimeters. The initial analysis of seismic signals recorded by seismic array allows us to detect low-energy seismic activity in the Elbrus volcanic area beginning from the distance of 3-5 km (the faults in a vicinity of mount Andyrchi) up to 15-25 km (area of Elbrus volcano). The regional micro-earthquakes with magnitude 1-2 at the distances 50-100 km was also recorded. 2.5 km aperture of the underground linear seismic array make it possible to determine with high accuracy hypocenters of local seismic events associated with geodynamic of volcanic magmatic structures and to realize seismo-emission tomography of the active zones of Elbrus volcano.

  17. Geology and stratigraphy of the Challis Volcanic Group and related rocks, Little Wood River area, south-central Idaho

    Sandford, Richard F.; Snee, Lawrence W.


    The southwestern part of the Challis volcanic field occupies the valley of the Little Wood River and its tributaries in the Hailey and Idaho Falls 1??2? quadrangles of south-central Idaho. The Little Wood River area is a structurally controlled topographic basin that is partly filled by Eocene Challis Volcanic Group and younger rocks. Rock types in the Challis Volcanic Group of the Little Wood River area include, in order of decreasing abundance, andesite lava flows and tuff breccia, dacite lava flows and flow breccia, volcaniclastic sedimentary rocks, lithic tuff, nonvolcanic conglomerate, and rhyolite dikes. A basal nonvolcanic conglomerate, that locally rests on upper Paleozoic sedimentary rocks at a regional unconformity, was deposited prior to eruption of volcanic rocks. Andesite was the first volcanic rock erupted and is a voluminous sequence as thick as 3,000 ft (1,000 m). Locally thick volcaniclastic sedimentary rocks accumulated in topographic lows. A sharp transition marks the beginning of dacite eruption from fissures and flow-dome complexes. Dacite flows and breccias are as thick as 2,000 ft (600 m). An upper volcaniclastic unit was deposited in paleotopographic lows following emplacement of the main dacite unit. Next, a widespread, distinctive, lithic rich ash flow tuff, correlated with the tuff of Stoddard Gulch, was deposited over much of the area. Deposition of the tuff was followed by eruption of thin andesite and dacite lava flows and deposition of conglomeratic sedimentary rocks. The entire sequence was then intruded by a dacite flow-dome complex composed of at least three separate intrusions. The Challis Volcanic Group in the study area is calcalkaline. Andesitic rocks are typically high potassium basaltic andesite, high potassium andesite, shoshonite, and banakite (latite). Dacitic rocks are high potassium dacite and trachyte. Tuffs and vitrophyres range in composition from basaltic andesite to trachyte. The paleotopographic basin in which the

  18. Mineral chemical compositions of late Cretaceous volcanic rocks in the Giresun area, NE Turkey: Implications for the crystallization conditions

    Oǧuz, Simge; Aydin, Faruk; Uysal, İbrahim; Şen, Cüneyt


    This contribution contains phenocryst assemblages and mineral chemical data of late Cretaceous volcanic (LCV) rocks from the south of Görele and Tirebolu areas (Giresun, NE Turkey) in order to investigate their crystallization conditions. The LCV rocks in the study area occur in two different periods (Coniasiyen-Early Santonian and Early-Middle Campanian), which generally consist of alternation of mafic-intermediate (basaltic to andesitic) and felsic rock series (dacitic and rhyolitic) within each period. The basaltic and andesitic rocks in both periods generally exhibit porphyritic to hyalo-microlitic porphyritic texture, and contain phenocrysts of plagioclase and pyroxene, whereas the dacitic and rhyolitic rocks of the volcanic sequence usually show a vitrophyric texture with predominant plagioclase, K-feldspar, quartz and lesser amphibole-biotite phenocrysts. Zoned plagioclase crystals of the mafic and felsic rocks in different volcanic periods are basically different in composition. The compositions of plagioclase in the first-stage mafic rocks range from An52 to An78 whereas those of plagioclase from the first-stage felsic rocks have lower An content varying from An38 to An50. Rim to core profile for the zoned plagioclase of the first-stage mafic rocks show quite abrupt and notable compositional variations whereas that of the first-stage felsic rocks show slight compositional variation, although some of the grains may display reverse zoning. On the other hand, although no zoned plagioclase phenocryst observed in the second-stage mafic rocks, the compositions of microlitic plagioclase show wide range of compositional variation (An45-80). The compositions of zoned plagioclase in the second-stage felsic rocks are more calcic (An65-81) than those of the first-stage felsic rocks, and their rim to core profile display considerable oscillatory zoning. The compositions of pyroxenes in the first- and second-stage mafic-intermediate rocks vary over a wide range from

  19. Groundwater flow in a relatively old oceanic volcanic island: the Betancuria area, Fuerteventura Island, Canary Islands, Spain.

    Herrera, Christian; Custodio, Emilio


    The island of Fuerteventura is the oldest of the Canary Islands' volcanic archipelago. It is constituted by volcanic submarine and subaerial activity and intrusive Miocene events, with some residual later volcanism and Quaternary volcanic deposits that have favored groundwater recharge. The climate is arid, with an average rainfall that barely attains 60 mm/year in the coast and up to 200 mm/year in the highlands. The aquifer recharge is small but significant; it is brackish due to large airborne atmospheric salinity, between 7 and 15 gm(-2)year(-1) of chloride deposition, and high evapo-concentration in the soil. The average recharge is estimated to be less than about 5 mm/year at low altitude and up to 10 mm/year in the highlands, and up to 20 mm/year associated to recent lava fields. Hydrochemical and water isotopic studies, supported by water table data and well and borehole descriptions, contribute a preliminary conceptual model of groundwater flow and water origin in the Betancuria area, the central area of the island. In general, water from springs and shallow wells tends to be naturally brackish and of recent origin. Deep saline groundwater is found and is explained as remnants of very old marine water trapped in isolated features in the very low permeability intrusive rocks. Preliminary radiocarbon dating indicates that this deep groundwater has an apparent age of less than 5000 years BP but it is the result of mixing recent water recharge with very old deep groundwater. Most of the groundwater flow occurs through the old raised volcanic shield of submarine and subaerial formations and later Miocene subaerial basalts. Groundwater transit time through the unsaturated zone is of a few decades, which allows the consideration of long-term quasi-steady state recharge. Transit times are up to a few centuries through the saturated old volcanics and up to several millennia in the intrusive formations, where isolated pockets of very old water may exist.

  20. Groundwater flow in a relatively old oceanic volcanic island: The Betancuria area, Fuerteventura Island, Canary Islands, Spain

    Herrera, Christian, E-mail: [Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Custodio, Emilio [Department of Geo-Engineering, Technical University of Catalonia (UPC), Barcelona (Spain)


    The island of Fuerteventura is the oldest of the Canary Islands' volcanic archipelago. It is constituted by volcanic submarine and subaerial activity and intrusive Miocene events, with some residual later volcanism and Quaternary volcanic deposits that have favored groundwater recharge. The climate is arid, with an average rainfall that barely attains 60 mm/year in the coast and up to 200 mm/year in the highlands. The aquifer recharge is small but significant; it is brackish due to large airborne atmospheric salinity, between 7 and 15 g m{sup −2} year{sup −1} of chloride deposition, and high evapo-concentration in the soil. The average recharge is estimated to be less than about 5 mm/year at low altitude and up to 10 mm/year in the highlands, and up to 20 mm/year associated to recent lava fields. Hydrochemical and water isotopic studies, supported by water table data and well and borehole descriptions, contribute a preliminary conceptual model of groundwater flow and water origin in the Betancuria area, the central area of the island. In general, water from springs and shallow wells tends to be naturally brackish and of recent origin. Deep saline groundwater is found and is explained as remnants of very old marine water trapped in isolated features in the very low permeability intrusive rocks. Preliminary radiocarbon dating indicates that this deep groundwater has an apparent age of less than 5000 years BP but it is the result of mixing recent water recharge with very old deep groundwater. Most of the groundwater flow occurs through the old raised volcanic shield of submarine and subaerial formations and later Miocene subaerial basalts. Groundwater transit time through the unsaturated zone is of a few decades, which allows the consideration of long-term quasi-steady state recharge. Transit times are up to a few centuries through the saturated old volcanics and up to several millennia in the intrusive formations, where isolated pockets of very old water may

  1. Deformation in volcanic areas: a numerical approach for their prediction in Teide volcano (Tenerife, Canary Islands); Deformaciones en areas volcanicas: una aproximacin numerica para su prediccion en el volcan Teide (Tenerife, Islas Canarias)

    Charco, M.; Galan del Sastre, P.


    Active volcanic areas study comprises both, observation of physical changes in the natural media and the interpretation of such changes. Nowadays, the application of spatial geodetic techniques, such as GPS (Global Positioning System) or InSAR (Interferometry with Synthetic Aperture Radar), for deformation understanding in volcanic areas, revolutionizes our view of this geodetic signals. Deformation of the Earth's surface reflects tectonic, magmatic and hydrothermal processes at depth. In this way, the prediction of volcanic deformation through physical modelling provides a link between the observation and depth interior processes that could be crucial for volcanic hazards assessment. In this work, we develop a numerical model for elastic deformation study. The Finite Element Method (FEM) is used for the implementation of the numerical model. FEM allows to take into account different morphology, structural characteristics and the mechanical heterogeneities of the medium. Numerical simulations of deformation in Tenerife (Canary Islands) taking into account different medium hypothesis allow us to conclude that the accuracy of the predictions depends on how well the natural system is described. (Author) 22 refs.

  2. Preliminary Findings of Petrology and Geochemistry of The Aladaǧ Volcanic System and Surrounding Areas (Kars, Turkey)

    Duru, Olgun; Keskin, Mehmet


    Between the towns of Sarıkamış and Kaǧızman, NE Turkey, a medium-sized strato-volcano with satellite cones and domes on its slopes unconformably overlies the Erzurum-Kars Volcanic Plateau (EKVP) with a subhorizontal contact. It is called the Aladaǧ volcanic system (AVS). Dating results indicate that the AVS is Pliocene in age. The EKVP is known to be formed by a widespread volcanism between Middle Miocene to Pliocene. The young volcanism in E Turkey including the study area is linked to a collision between the Eurasia and Arabian continents, started almost 15 Ma ago. The EKVP lies over 2000 m above the sea level, and is deeply cut by the river Aras. On the slopes of the valley, one of the best volcano-stratigraphic transects of Eastern Anatolia, almost half a km thick, is exposed. That transect is composed of aphyric andesites-dacites, ignimbrites, tuffs, perlite and obsidian bands. Pyroclastic fall and surge-related pumice deposits are also widespread. Top of the plateau is composed of the andesitic to basaltic andesitic lavas containing plagioclase (Plg) and ortho/clino pyroxene (Opx/Cpx) phenocrysts set in glassy groundmass. In the northwest of the study area, an eroded stratovolcano, probably coeval with the plateau sequence is situated. It also consists of high-silica rhyolites and pyroclastic equivalents. The AVS is composed basically of intermediate lavas. The largest volcanic edifice of the Aladaǧ volcanic system, namely the Greater Aladaǧ stratovolcano reaches up to 3000 m height and includes a horseshoe shaped crater open to the North. Small volcanic cones and domes sit on the flanks of the Greater Aladaǧ volcano. The Aladaǧ lavas are divided into four sub-groups on the basis of their stratigraphic positions, mineral assemblages and textural properties. (1) The oldest products of the Greater Aladaǧ stratovolcano are andesitic and dasitic lavas. They directly sit on the EKVP. These are Plg and Opx/Cpx bearing lavas with porphric, vitrophyric

  3. Relationship between chemical composition and magnetic susceptibility in the alkaline volcanics from the Isparta area, SW Turkey

    Ömer Elitok; Züheyr Kamacı; M Nuri Dolmaz; Kamil Yılmaz; Meltem Şener


    Potassium-rich volcanic rocks in the Isparta area (SW Turkey)consist mainly of older (Pliocene) volcanic rock suites (e.g., lamprophyre, basaltic trachyandesite, trachyandesite, trachyte) and younger (Quaternary) caldera forming lava dome/flows (e.g., tephriphonolite, trachyte) and pyroclastics (ash/pumice fall deposits and ignimbritic flows). The magnetic susceptibility () was performed for both groups. The magnetic susceptibility value of the less evolved rocks characterized by SiO2 > 57 wt%(e.g., basaltic trachyandesite, tephriphonolite, lamprophyric rocks) and having mostly mafic phenocrysts such as pyroxene, amphibole, and biotite-phlogopite is over 10 (10−3 [SI]). Fine to medium-grained and subhedral to anhedral opaque minerals are scattered especially in the matrix phase of the less evolved volcanic rocks. However, the value of the more evolved rocks (e.g., trachyte and trachyandesites) with SiO2 over 57 wt%vary between 0.1 and 28, but most of them below 10.SI values are negatively correlated with SiO2, Na2O, but positively correlated with Fe2O3, CaO, MnO, P2O5 and MgO contents, suggesting inverse variation of SI with fractionation of potassic magma. That is to say that less evolved volcanic rocks have relatively higher magnetic susceptibility values in the volcanic suite.Fine to medium-grained and subhedral to anhedral Fe-Ti oxides are scattered mainly in the matrix phase of the less evolved volcanics, presumably cause the pronounced relatively higher magnetic susceptibility.

  4. Prediction of ground motion parameters for the volcanic area of Mount Etna

    Tusa, Giuseppina; Langer, Horst


    Ground motion prediction equations (GMPEs) have been derived for peak ground acceleration (PGA), velocity (PGV), and 5 % damped spectral acceleration (PSA) at frequencies between 0.1 and 10 Hz for the volcanic area of Mt. Etna. The dataset consists of 91 earthquakes with epicentral distances between 0.5 and 100 km. Given the specific characteristics of the area, we divided our data set into two groups: shallow events (SE, focal depth 5 km). The range of magnitude covered by the SE and the DE is 3.0 ≤ M L ≤ 4.3 and 3.0 ≤ M L ≤ 4.8, respectively. Signals of DE typically have more high frequencies than those of SE. These differences are clearly reflected in the empirical GMPEs of the two event groups. Empirical GMPEs were estimated considering several functional forms: Sabetta and Pugliese (Bull Seism Soc Am 77:1491-1513, 1987) (SP87), Ambraseys et al. (Earth Eng Struct Dyn 25:371-400, 1996) (AMB96), and Boore and Atkinson (Earth Spectra 24:99-138, 2008) (BA2008). From ANOVA, we learn that most of the errors in our GMPEs can be attributed to unmodeled site effects, whereas errors related to event parameters are limited. For DE, BA2008 outperforms the simpler models SP87 or AMB96. For SE, the simple SP87 is preferable considering the Bayesian Information Criterion since it proves more stable with respect to confidence and gives very similar or even lower prediction errors during cross-validation than the BA2008 model. We compared our results to relationships derived for Italy (ITA10, Bindi et al. Bull Earth Eng 99:2471-2488, 2011). For SE, the main differences are observed for distances greater than about 5 km for both horizontal and vertical PGAs. Conversely, for DE the ITA10 heavily overestimates the peak ground parameters for short distances.

  5. SHRIMP dating of volcanic rock in the Zhangwu-Heishan area, West Liaoning province, China: Its relationship with coal-bearing strata

    Cai Houan; Xu Debin; Li Baofang; Shao Longyi


    The Zhangwu-Heishan area is located to the east of the Fuxin-Yixian Basin and is mostly covered with volcanic rock.At various periods,different geologists had varying opinions about their age and periods of volcanic eruptions,especially on sequences between volcanic rock and main coal-beating strata,which affect the direction of searching for coal,as well as prospecting the entire research area.During our study,we carried out detailed field investigations in this research area; observed and recorded the main representative outcrops of volcanic rock.We collected over 20 volcanic rock samples and tested the Sensitive High Resolution Ion Microprobe Ⅱ (SHRIMP Ⅱ) U-Pb isotope age of 11 samples.The age of our volcanic rock samples ranged between 56.0 ± 2.9 and 132.3 ± 2.3 Ma.After taking earlier investigations into consideration,we concluded that,except for a suite of paleogene olivine basalt,the volcanic rock in the Zhangwu-Heishan area is younger than the coal-beating Shahai Formation.It is therefore most unlikely to find coal seams equivalent to those of the early Cretaceous Shahai Formation in Fuxin Basin below volcanic rock.

  6. Monitoring and behavior of unsaturated volcanic pyroclastic in the Metropolitan Area of San Salvador, El Salvador.

    Chávez, José Alexander; Landaverde, José; Landaverde, Reynaldo López; Tejnecký, Václav


    Field monitoring and laboratory results are presented for an unsaturated volcanic pyroclastic. The pyroclastic belongs to the latest plinian eruption of the Ilopango Caldera in the Metropolitan Area of San Salvador, and is constantly affected by intense erosion, collapse, slab failure, sand/silt/debris flowslide and debris avalanche during the rainy season or earthquakes. Being the flowslides more common but with smaller volume. During the research, preliminary results of rain threshold were obtained of flowslides, this was recorded with the TMS3 (a moisture sensor device using time domain transmission) installed in some slopes. TMS3 has been used before in biology, ecology and soil sciences, and for the first time was used for engineering geology in this research. This device uses electromagnetic waves to obtain moisture content of the soil and a calibration curve is necessary. With the behavior observed during this project is possible to conclude that not only climatic factors as rain quantity, temperature and evaporation are important into landslide susceptibility but also information of suction-moisture content, seepage, topography, weathering, ground deformation, vibrations, cracks, vegetation/roots and the presence of crust covering the surface are necessary to research in each site. Results of the field monitoring indicates that the presence of biological soil crusts a complex mosaic of soil, green algae, lichens, mosses, micro-fungi, cyanobacteria and other bacteria covering the slopes surface can protect somehow the steep slopes reducing the runoff process and mass wasting processes. The results obtained during the assessment will help explaining the mass wasting problems occurring in some pyroclastic soils and its possible use in mitigation works and early warning system.

  7. Late cenozoic vertical movements of non-volcanic islands in the Banda Arc area

    De Smet, M. E. M.; Fortuin, A. R.; Tjokrosapoetro, S.; Van Hinte, J. E.

    During onshore campaigns of the Snellius-II Expedition late Cenozoic sections were recorded and systematically sampled on the non-volcanic outer Banda Arc Islands of Timor, Buton, Buru, Seram and Kai. Microfaunal studies provided age and palaeobathymetric data to construct geohistory diagrams. Geohistory analysis of field and laboratory data allows to calculate rates of vertical movements of the island basements. The vertical movements were intermittent and differed widely from place to place in the arc; short periods of uplift alternated with longer periods of tectonic rest or subsidence and lateral variations in timing and magnitude seem to be more the rule than the exception. Movements affected larger segments of the arc at about the same time, especially since the late Pliocene, when widespread vertical movements started, which led to the present configuration of the arc. Rates of uplift or subsidence differed within each segment. On an intermediate scale, deformation has the character of tilting or doming of whole islands or parts of islands. On a local scale, various types of deformation occur. Calculated duration of uplift pulses is in the order of a million years where less than 50 cm·ka -1 of vertical movements are involved. Sections, however, with a high time stratigraphic resolutions show pulses of uplift with a duration of only some hundreds of thousands of years and rates of more than 500 cm·ka -1. The duration of such pulses therefore is comparable to that of eustatic third order sea level changes. But because their amplitude is an order of magnitude larger, this implies that in tectonically active areas eustatic signals, preserved in the sedimentary record, will be overprinted by tectonics, i.e. will be difficult to disentangle from the tectonic signal.

  8. Bromo volcano area as human-environment system: interaction of volcanic eruption, local knowledge, risk perception and adaptation strategy

    Bachri, Syamsul; Stötter, Johann; Sartohadi, Junun


    People in the Bromo area (located within Tengger Caldera) have learn to live with the threat of volcanic hazard since this volcano is categorized as an active volcano in Indonesia. During 2010, the eruption intensity increased yielding heavy ash fall and glowing rock fragments. A significant risk is also presented by mass movement which reaches areas up to 25 km from the crater. As a result of the 2010 eruption, 12 houses were destroyed, 25 houses collapsed and there were severe also effects on agriculture and the livestock sector. This paper focuses on understanding the interaction of Bromo volcanic eruption processes and their social responses. The specific aims are to 1) identify the 2010 eruption of Bromo 2) examine the human-volcano relationship within Bromo area in general, and 3) investigate the local knowledge related to hazard, risk perception and their adaptation strategies in specific. In-depth interviews with 33 informants from four districts nearest to the crater included local people and authorities were carried out. The survey focused on farmers, key persons (dukun), students and teachers in order to understand how people respond to Bromo eruption. The results show that the eruption in 2010 was unusual as it took continued for nine months, the longest period in Bromo history. The type of eruption was phreatomagmatic producing material dominated by ash to fine sand. This kind of sediment typically belongs to Tengger mountain eruptions which had produced vast explosions in the past. Furthermore, two years after the eruption, the interviewed people explained that local knowledge and their experiences with volcanic activity do not influence their risk perception. Dealing with this eruption, people in the Bromo area applied 'lumbung desa' (traditional saving systems) and mutual aid activity for surviving the volcanic eruption. Keywords: Human-environment system, local knowledge, risk perception, adaptation strategies, Bromo Volcano Indonesia

  9. Volcanic ash layers in blue ice fields (Beardmore Glacier Area, Antarctica): Iridium enrichments

    Koeberl, Christian


    Dust bands on blue ice fields in Antarctica have been studied and have been identified to originate from two main sources: bedrock debris scraped up from the ground by the glacial movement (these bands are found predominantly at fractures and shear zones in the ice near moraines), and volcanic debris deposited on and incorporated in the ice by large-scale eruptions of Antarctic (or sub-Antractic) volcanoes. Ice core studies have revealed that most of the dust layers in the ice cores are volcanic (tephra) deposits which may be related to some specific volcanic eruptions. These eruptions have to be related to some specific volcanic eruptions. These eruptions have to be relatively recent (a few thousand years old) since ice cores usually incorporate younger ice. In contrast, dust bands on bare blue ice fields are much older, up to a few hundred thousand years, which may be inferred from the rather high terrestrial age of meteorites found on the ice and from dating the ice using the uranium series method. Also for the volcanic ash layers found on blue ice fields correlations between some specific volcanoes (late Cenozoic) and the volcanic debris have been inferred, mainly using chemical arguments. During a recent field expedition samples of several dust bands found on blue ice fields at the Lewis Cliff Ice Tongue were taken. These dust band samples were divided for age determination using the uranium series method, and chemical investigations to determine the source and origin of the dust bands. The investigations have shown that most of the dust bands found at the Ice Tongue are of volcanic origin and, for chemical and petrological reasons, may be correlated with Cenozoic volcanoes in the Melbourne volcanic province, Northern Victoria Land, which is at least 1500 km away. Major and trace element data have been obtained and have been used for identification and correlation purposes. Recently, some additional trace elements were determined in some of the dust band

  10. Features of Minerogenic Series Related to Continental Volcanic Rocks in the Southeastern Coastal Area of China-A Case Study of the Daiyunshan-Shiniushan Volcanic Depression in Fujian


    The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in China , which are of economic importance for metallogenic prognosis .

  11. An Assessment Of Landscape Segments Suitable For Agriculture In Kerang Volcanic Area Of Jos Plateau Nigeria

    Sohotden Christopher Daniel


    Full Text Available Abstract This study was carried out to investigate the landscape segments suitable for agricultural purpose in a volcanic land catena of Kerang Area on the Jos Plateau. A reconnaissance survey of the study area was carried out and three different slope segments were identified a total of 41 surface soil samples were taken from the three segments using a stratified systematic sampling. These soils were then analyzed for the physical and chemical properties. The result of the analyses revealed that the organic matter total nitrogen soil PH and exchangeable Ca Mg decline down slope however potassium K and sodium Na increase down slope. Co-efficient of variation of the soil properties for the three different slope segments showed low variability for the upper slope crest and shoulder exception being that phosphorus 43.10 and potassium 41.10 exhibited moderate variability. At the middle slope the co-efficient of variation exhibited by soil properties is predominantly moderate exception being that sodium 75 varies at high proportion at this slope segment. At the lower slope majority of the soil properties exhibited low variability. On the other hand total nitrogen available phosphorous and potassium have values of co-efficient of variation 23.10 65.60 and 23.10 respectively. This indicates that available phosphorus exhibited high variability while total nitrogen and exchangeable potassium have intermediate variability. The between or over all co-efficient or variation for the soil properties are predominantly moderate for most variable except PHH2O 11.80 and PH Cad2 10.60 that have low variability and phosphorous 78 has high variability. Differences in the degree of variation of soil variables from one segment to another can be attributed to soil erosion as affected by slope nature of soil parent materials and soil management technique. The study also revealed that some of the properties determining soil fertility total Nitrogen Available Phosphorus

  12. Unsupervised Change Detection for Geological and Ecological Monitoring via Remote Sensing: Application on a Volcanic Area

    Falco, N.; Pedersen, G. B. M.; Vilmunandardóttir, O. K.; Belart, J. M. M. C.; Sigurmundsson, F. S.; Benediktsson, J. A.


    The project "Environmental Mapping and Monitoring of Iceland by Remote Sensing (EMMIRS)" aims at providing fast and reliable mapping and monitoring techniques on a big spatial scale with a high temporal resolution of the Icelandic landscape. Such mapping and monitoring will be crucial to both mitigate and understand the scale of processes and their often complex interlinked feedback mechanisms.In the EMMIRS project, the Hekla volcano area is one of the main sites under study, where the volcanic eruptions, extreme weather and human activities had an extensive impact on the landscape degradation. The development of innovative remote sensing approaches to compute earth observation variables as automatically as possible is one of the main tasks of the EMMIRS project. Furthermore, a temporal remote sensing archive is created and composed by images acquired by different sensors (Landsat, RapidEye, ASTER and SPOT5). Moreover, historical aerial stereo photos allowed decadal reconstruction of the landscape by reconstruction of digital elevation models. Here, we propose a novel architecture for automatic unsupervised change detection analysis able to ingest multi-source data in order to detect landscape changes in the Hekla area. The change detection analysis is based on multi-scale analysis, which allows the identification of changes at different level of abstraction, from pixel-level to region-level. For this purpose, operators defined in mathematical morphology framework are implemented to model the contextual information, represented by the neighbour system of a pixel, allowing the identification of changes related to both geometrical and spectral domains. Automatic radiometric normalization strategy is also implemented as pre-processing step, aiming at minimizing the effect of different acquisition conditions. The proposed architecture is tested on multi-temporal data sets acquired over different time periods coinciding with the last three eruptions (1980-1981, 1991

  13. Caldera resurgence as a possible cause of slope failure in volcanic areas: the Ischia island case history

    de Vita, Sandro; Seta Marta, Della; Paola, Fredi; Enrica, Marotta; Giovanni, Orsi; Fabio, Sansivero


    Slope instability in active volcanic areas is a factor of major hazard to be considered. Due to their rapid growth and deformation, active volcanoes experience gravitational disequilibrium and periodical structural failures. Depending on the geodynamic framework of a volcano, nature, style of activity and climatic conditions, slope instability occurs at different scales, from relatively small-volume mass movements to huge lahars and debris avalanches. Moreover, volcanoes located in coastal areas or islands, may experience lateral collapses with the potential to generate large tsunamis. Although there is very little literature on the relationships among caldera resurgence, volcanism and slope instability, recently also the caldera resurgence has been suggested as a possible cause of slope failure, as for the southern flank of the island of Ischia in the Southern Tyrrhenian sea (Italy). Ischia island gives a good opportunity to investigate such phenomena and related effects, as it is the only documented example of resurgent caldera in which, during uplift, volcanism and generation of mass movements have been very active and linked to each other in a sort of cyclical behaviour. The island of Ischia is one of the most impressive examples of resurgent calderas in the world. This caldera formed in response to a complex explosive eruption that, about 55 ka B.P., produced the Mt. Epomeo Green Tuff ignimbritic deposit. Starting from at least 30 ka B.P. the caldera floor has been uplifted of about 900 m, due to a resurgent phenomenon, which occurred through intermittent uplifting, likely triggered by the intrusion of new magma into the system, and tectonic quietness phases. During uplift, volcanism and generation of mass movements were very active. The resurgent area is composed of differentially displaced blocks and has a poligonal shape, resulting from reactivation of regional faults and activation of faults directly related to volcano-tectonism. The western sector is

  14. Freshwater molluscs from volcanic areas as model organisms to assess adaptation to metal chronic pollution

    Zaldibar, Benat [Biologia Zelularra eta Histologia laborategia, Zoologia eta Animalien Biologia Zelularra Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 P.K. E-48080 Bilbo, Basque Country (Spain); Rodrigues, Armindo [Cirn e Departamento Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal); Lopes, Marco [Cirn e Departamento Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal); Amaral, Andre [Cirn e Departamento Biologia, Universidade dos Acores, R. Mae de Deus, APT 1422, PT-9501-855 Ponta Delgada (Portugal); Marigomez, Ionan [Biologia Zelularra eta Histologia laborategia, Zoologia eta Animalien Biologia Zelularra Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 P.K. E-48080 Bilbo, Basque Country (Spain); Soto, Manu [Biologia Zelularra eta Histologia laborategia, Zoologia eta Animalien Biologia Zelularra Saila, Zientzi Fakultatea, Euskal Herriko Unibertsitatea, 644 P.K. E-48080 Bilbo, Basque Country (Spain)]. E-mail:


    Cellular biomarkers of exposure and biological effects were measured in digestive gland of snails (Physa acuta) sampled in sites with and without active volcanism in Sao Miguel Island (Azores). Metal content in digestive cell lysosomes was determined by image analysis after autometallography (AMG) as volume density of autometallographed black silver deposits (Vv{sub BSD}). Lysosomal structural changes (lysosomal volume, surface and numerical densities - Vv{sub LYS,} Sv{sub LYS} and Nv{sub LYS-}, and surface-to-volume ratio - S/V{sub LYS}-) were quantified by image analysis, after demonstration of {beta}-glucuronidase activity, on digestive gland cryotome sections. Additional chemical analyses (atomic absorption spectrophotometry) were done in the digestive gland of snails. The highest metal concentrations were found in snails from the active volcanic site, which agreed with high intralysomal Vv{sub BSD}. Digestive cell lysosomes in snails inhabiting sites with active volcanism resembled a typical stress situation (enlarged and less numerous lysosomes). In conclusion, the biomarkers used in this work can be applied to detect changes in metal bioavailability due to chronic exposure to metals (volcanism), in combination with chemical analyses.

  15. Volcanostratigraphy, petrography and petrochemistry of Late Cretaceous volcanic rocks from the Görele area (Giresun, NE Turkey)

    Oguz, Simge; Aydin, Faruk; Baser, Rasim


    In this study, we have reported for lithological, petrographical and geochemical features of late Cretaceous volcanic rocks from the Çanakçı and the Karabörk areas in the south-eastern part of Görele (Giresun, NE Turkey) in order to investigate their origin and magmatic evolution. Based on the previous ages and recent volcano-stratigraphic studies, the late Cretaceous time in the study area is characterized by an intensive volcanic activity that occurred in two different periods. The first period of the late Cretaceous volcanism (Cenomanian-Santonian; 100-85 My), conformably overlain by Upper Jurassic-Lower Cretaceous massive carbonates (Berdiga Formation), is represented by bimodal units consisting of mainly mafic rock series (basaltic-andesitic lavas and hyaloclastites, dikes and sills) in the lower part (Çatak Formation), and felsic rock series (dacitic lavas and hyaloclastites, crystal- and pyrite-bearing tuffs) in the upper part (Kızılkaya Formation). The second period of the late Cretaceous volcanism (Santonian-Late Campanian; 85-75 Ma) is also represented by bimodal character and again begins with mafic rock suites (basaltic-basaltic andesitic lavas and hyaloclastites) in the lower part (Çağlayan Formation), and grades upward into felsic rock suites (biotite-bearing rhyolitic lavas, ignimbrites and hyaloclastites) through the upper part (Tirebolu Formation). These bimodal units are intercalated with volcanic conglomerates-sandstones, claystones, marl and red pelagic limestones throughout the volcanic sequence, and the felsic rock series have a special important due to hosting of volcanogenic massive sulfide deposits in the region. All volcano-sedimentary units are covered by Tonya Formation (Late Campanian-Paleocene) containing calciturbidites, biomicrites and clayey limestones. The mafic rocks in the two volcanic periods generally include basalt, basaltic andesite and minor andesite, whereas felsic volcanics of the first period mainly consists of

  16. Hazard and risk assessment in a complex multi-source volcanic area: the example of the Campania Region, Italy

    Lirer, L.; Petrosino, P.; Alberico, I.


    In order to zone the territory of Campania Region (southern Italy) with regard to the hazard related to future explosive activity of Somma-Vesuvio, Campi Flegrei, and Ischia Island, we drew a multi-source hazard map for tephra and pyroclastic flows. This map, which merges the areas possibly endangered by the three volcanic sources, takes into account a large set of tephra fall and pyroclastic flow events that have occurred in the last 10 ka. In detail, for fall products at Campi Flegrei and Somma-Vesuvio we used the dispersal of past eruption products as deduced by field surveys and their recurrence over the whole area. For pyroclastic flows, the field data were integrated with VEI = 4 simulated events; about 100 simulations sourcing from different points of the area were performed, considering the different probability of vent opening. The spatial recurrence of products of both past eruptions and simulated events was used to assign a weight to the area endangered by the single volcanic sources. The sum of these weights in the areas exposed to the activity of two sources and/or to different kinds of products was used to draw a hazard map, which highlights the spatial trend and the extent of the single equivalent classes at a regional scale. A multi-source risk map was developed for the same areas as the graphic result of the product of volcanic hazard and exposure, assessed in detail from a dasymetric map. The resulting multi-source hazard and risk maps are essential tools for communication among scientists, local authorities, and the public, and may prove highly practical for long-term regional-scale mitigation planning.

  17. 14 CFR 121.113 - Area and route requirements: General.


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Area and route requirements: General. 121... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Approval of Areas and Routes for Supplemental Operations § 121.113 Area and route requirements: General. (a) Each certificate holder...

  18. Neotectonics of Graciosa island (Azores: a contribution to seismic hazard assessment of a volcanic area in a complex geodynamic setting

    Ana Hipólito


    Full Text Available Graciosa is a mid-Pleistocene to Holocene volcanic island that lies in a complex plate boundary between the North American, Eurasian, and Nubian plates. Large fault scarps displace the oldest (Middle Pleistocene volcanic units, but in the younger areas recent volcanism (Holocene to Upper Pleistocene conceals the surface expression of faulting, limiting neotectonic observations. The large displacement accumulated by the older volcanic units when compared with the younger formations suggests a variability of deformation rates and the possibility of alternating periods of higher and lower tectonic deformation rates; this would increase the recurrence interval of surface rupturing earthquakes. Nevertheless, in historical times a few destructive earthquakes affected the island attesting for its seismic hazard. Regarding the structural data, two main fault systems, incompatible with a single stress field, were identified at Graciosa Island. Thus, it is proposed that the region is affected by two alternating stress fields. The stress field #1 corresponds to the regional stress regime proposed by several authors for the interplate shear zone that constitutes the Azorean segment of the Eurasia-Nubia plate boundary. It is suggested that the stress field #2 will act when the area under the influence of the regional stress field #1 narrows as a result of variations in the differential spreading rates north and south of Azores. The islands closer to the edge of the sheared region will temporarily come under the influence of a different (external stress field (stress field #2. Such data support the concept that, in the Azores, the Eurasia-Nubia boundary corresponds to a complex and wide deformation zone, variable in time.

  19. Estimated water requirements : Stillwater Wildlife Management Area

    US Fish and Wildlife Service, Department of the Interior — An estimated 84,850 acre-feet of water are required annually to maintain 23,231 acres of marsh currently developed on the Stillwater WMA. An additional 34,003...

  20. Petrology and petrogenesis of the Eocene Volcanic rocks in Yildizeli area (Sivas), Central Anatolia, Turkey

    Doğa Topbay, C.; Karacık, Zekiye; Genç, S. Can; Göçmengil, Gönenç


    Yıldızeli region to the south of İzmir Ankara Erzincan suture zone is situated on the large Sivas Tertiary sedimentary basin. After the northern branch of the Neotethyan Ocean was northerly consumed beneath the Sakarya Continent, a continent - continent collision occurred between the Anatolide- Tauride platform and Pontides and followed a severe intermediate magmatism during the Late Cretaceous- Tertiary period. This created an east-west trending volcanic belt along the whole Pontide range. In the previous studies different models are suggested for the Eocene volcanic succession such as post-collisional, delamination and slab-breakoff models as well as the arc model for its westernmost parts. We will present our field and geochemical data obtained from the Yıldızeli and its surroundings for its petrogenesis, and will discuss the tectonic model(s) on the basis of their geochemical/petrological aspects. Cenozoic volcanic sequences of Yıldızeli region which is the main subject of this study, overlie Pre-Mesozoic crustal meta-sedimentary group of Kırşehir Massif, Ophiolitic mélange and Cretaceous- Paleocene? flysch-like sequences. In the northern part of Yıldızeli region, north vergent thrust fault trending E-W seperates the ophiolitic mélange complex from the Upper Cretaceous-Paleocene and Tertiary formations. Volcano-sedimentary units, Eocene in age, of the Yıldızeli (Sivas-Turkey) which are intercalated with sedimentary deposits related to the collision of Anatolide-Tauride and a simultaneous volcanic activity (i.e. the Yıldızeli volcanics), exposed throughout a wide zone along E-W orientation. Yıldızeli volcanics consist of basalts, basaltic-andesites and andesitic lavas intercalated flow breccias and epiclastic, pyroclastic deposits. Basaltic andesite lavas contain Ca-rich plagioclase + clinopyroxene ± olivine with minor amounts of opaque minerals in a matrix comprised of microlites and glass; andesitic lavas are generally contain Ca

  1. Visualization and comparison of DEM-derived parameters. Application to volcanic areas

    Favalli, Massimiliano; Fornaciai, Alessandro


    Digital Elevation Models (DEMs) are fruitfully used in volcanology as the topographic base for mapping and quantifying volcanic landforms. The increasing availability of free topographic data on the web, decreasing production costs for high-accuracy data and advances in computer technology, has triggered rapid growth of the number of DEM users in the volcanological community. DEMs are often visualized only as hill-shaded maps, and while this is among the major advantages in using them, the possibility of deriving a very large number of parameters from a single grid of elevation data makes DEMs a powerful tool for morphometric analysis. However, many of these parameters have almost the same informative content, and before starting to elaborate topographic data it is recommended to know a-priori what parameters best visualize the investigated landform, and therefore what is necessary and what is redundant. In this work, we review a number of analytical procedures used to parameterize and represent DEMs. A LIDAR-derived DEM matrix acquired over the Valle del Bove valley, on Mt. Etna, is used as test-case elevation data for deriving the parameters. We first review well known parameters such as hill-shading, slope and aspect, curvature, and roughness, before extending the review to some less common parameters such as Sky View Factor (SVF), openness, and Red Relief Image Maps (RRIM). For each parameter a description is given emphasizing how it can be used for identifying and delimiting specific volcanic elements. The analyzed surface parameters are then cross-compared in order to infer which of them is most uncorrelated, and the results are represented in the form of a correlation matrix. Finally, the reviewed DEM-derived parameters and the correlation matrix are used for analyzing the volcanic landforms of two case studies: Michoacán-Guanajuato volcanic field and a phonolitic lava flow at the Island of Tenerife.

  2. Surface area, porosity and water adsorption properties of fine volcanic ash particles

    Delmelle, Pierre; Villiéras, Frédéric; Pelletier, Manuel


    Our understanding on how ash particles in volcanic plumes react with coexisting gases and aerosols is still rudimentary, despite the importance of these reactions in influencing the chemistry and dynamics of a plume. In this study, six samples of fine ash (500 Å. All the specimens had similar pore size distributions, with a small peak centered around 50 Å. These findings suggest that fine ash particles have relatively undifferentiated surface textures, irrespective of the chemical composition and eruption type. Adsorption isotherms for water vapour revealed that the capacity of the ash samples for water adsorption is systematically larger than predicted from the nitrogen adsorption as values. Enhanced reactivity of the ash surface towards water may result from (i) hydration of bulk ash constituents; (ii) hydration of surface compounds; and/or (iii) hydroxylation of the surface of the ash. The later mechanism may lead to irreversible retention of water. Based on these experiments, we predict that volcanic ash is covered by a complete monolayer of water under ambient atmospheric conditions. In addition, capillary condensation within ash pores should allow for deposition of condensed water on to ash particles before water reaches saturation in the plume. The total mass of water vapour retained by 1 g of fine ash at 0.95 relative water vapour pressure is calculated to be ~10-2 g. Some volcanic implications of this study are discussed.

  3. Chronology and Geochemistry of Mesozoic Volcanic Rocks in the Linjiang Area, Jilin Province and their Tectonic Implications

    YU Yang; XU Wenliang; PEI Fuping; YANG Debin; ZHAO Quanguo


    Zircon U-Pb ages and geochemical analytical results are presented for the volcanic rocks of the Naozhigou, Ergulazi, and Sidaogou Formations in the Linjiang area, southeastern Jilin Province to constrain the nature of magma source and their tectonic settings. The Naozhigou Formation is composed mainly of andesite and rhyolite and its weighted mean 206Pb/238U age for 13 zircon grains is 2224±1 Ma. The Ergulazi Formation consists of basaltic andesite, basaltic trachyandesite, and andesite, and six grains give a weighted mean 206Pb/238U age of 131±4 Ma. The Sidaogou Formation consists mainly of trachyandesite and rhyolite, and six zircon grains yield a weighted mean 206Pb/238U age of113±4 Ma. The volcanic rocks have SiO2=60.24%-77.46%, MgO=0.36%-1.29% (Mg#=0.32-0.40) for the Naozhigou Formation, SiO2=51.60%-59.32 %, MgO=3.70 %-5.54% (Mg#=0.50-0.60) for the Ergulazi Formation, and SiO2=58.28%-76.32%, MgO=0.07%-1.20% (Mg#=0.14-0.46) for the Sidaogou Formation. The trace element analytical results indicate that these volcanic rocks are characterized by enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), relative depletion in heavy rare earth elements (HREEs) and high field strength elements (HFSEs, Nb, Ta, and Ti), and negative Eu anomalies. Compared with the primitive mantle, the Mesozoic volcanic rocks in the Linjiang area have relatively high initial 87Sr/86Sr ratios (0.7053-0.7083) and low eNd(t) values (-8.38 to -2.43), and display an EMII trend. The late Triassic magma for the Naozhigou Formation could be derived from partial melting of a newly accretional crust with the minor involvement of the North China Craton basement and formed under an extensional environment after the collision of the Yangtze Craton and the North China Craton. The Early Cretaceous volcanic rocks for the Ergulazi and Sidaogou Formations could be formed under the tectonic setting of an active continental margin related to the westward snbduction of

  4. [Micro-area characteristics of laminated chert in the volcanic rocks of Xionger Group of Ruyang area and its geological significances].

    Luo, An; Li, Hong-zhong; Zhao, Ming-zhen; Yang, Zhi-jun; Liang, Jin; He, Jun-guo


    The Xionger Group was originated from the volcanic eruption and sedimentation in Precambrian, whose sedimentary strata at the top were named Majiahe Formation. In the Majiahe Formation, there were hydrothermal chert widely distributed, which were exhibited to be interlayers in the volcanic rocks. The polarized microscope, X-ray diffraction (XRD), Raman and electron back scatter diffraction (EBSD) were conducted to study the characteristics in micro area of the jasperite samples, which were from the sedimentary interlayers in the volcanic rocks of Majiahe Formation in Xionger Group. As shown in the microphotographs and EBSD images, the quartz in the chert had small grain size, low degree of crystallinity and close packed structure, which quite agreed with the characteristics of hydrothermal sedimentary chert. In the chert of Xionger Group, there were clear banded (or lamellar) structures which were contributed by the diversities of the grain size and mineral composition. The different bands (or lamellars) had alternative appearance repeatedly, and denoted the diversities and periodic changes in the substance supply during the precipitation. According to the results of the XRD analysis, the majority minerals of the chert was low temperature quartz, whose lattice parameters were a=b=0.4913 nm, c=0.5405 nm and Z=3. As denoted in the EBSD image and result of Raman analysis, several impurity minerals were formed in the chert in different stages, whose geneses and formation time were quite different. The clay minerals and pyrite were scattered in distribution, and should be contributed by the original sedimentation. On contrary, the felsic minerals and mafic silicate minerals were originated from the sedimentation of tuffaceous substance during the volcanic eruption. The minerals of volcanic genesis had relatively larger grain size, and they deposited together with the hydrothermal sediments to form the bands (or lamellars) of coarse minerals. However, the hydrothermal

  5. Geology and petrology of Tertiary volcanic rocks of Sarbisheh perlite mine area (eastern Iran and industrial applications

    Seayad Sayid Mohammadi


    Full Text Available The study area is located at northwest of Sarbisheh in South Khorasan province and eastern border of Lut block. In this area, Tertiary (Eocene-Oligocene to Pliocene volcanic rocks consisting of basaltic andesite, dacite, rhyodacite, vitreous rhyolite (perlitic in some parts, tuff and ignimbrite are exposed. In the Daghar Mountain, A, B and C perlite layers with thicknesses of 102, 7 and 58 meters respectively, occur alternatively with volcanic-pyroclastic rocks. Zoning, sieve texture and embayment of plagioclase and roundness of minerals in the lavas indicate disequilibrium conditions during magma crystallization. Chemically, these are meta-aluminous, medium to high-K calc-alkaline, enriched in LILE and negative anomaly for Nb and Ti. Chondrite-normalized Rare Earth Elements (REE plots indicate enrichment of light REE in comparison with heavy REE, (La/YbN of 9.14-12.64, low negative anomaly for Eu in basaltic andesite (Eu/Eu*=0.91 and dacite (Eu/Eu*=0.78-0.87 and strong negative anomaly for Eu in the rhyolites (Eu/Eu*=0.18-0.35. Negative anomaly for Eu indicates calc-alkaline nature for these rocks. On the basis of chemical characteristics and magnetic susceptibility, these are I-type. Tectonically, the rocks belong to subduction zone and active continental margin and their parental magma originated from partial melting of enriched mantle and then crustal contamination during differentiation process. Dacites have an initial 87Sr/86Sr between 0.7048 and 0.7050 (average 0.7049 that confirm mantle source for the magma. Volcanic glasses of rhyolitic composition altered by hydration (likely meteoric water and formed perlite. Physical tests and chemical analyses show that perlite of Sarbisheh is suitable as raw material for production of expanded perlite.

  6. Sensitivity of two biomarkers for biomonitoring exposure to fluoride in children and women: A study in a volcanic area.

    Linhares, Diana Paula Silva; Garcia, Patrícia Ventura; Amaral, Leslie; Ferreira, Teresa; Cury, Jaime A; Vieira, Waldomiro; Rodrigues, Armindo Dos Santos


    The natural enrichment of water with fluoride is related to natural sources such as volcanic activity, with it being documented that fluorosis, an endemic and widespread disease in volcanic areas, is associated to the ingestion of high levels of fluoride through water. Thus, in this study, we aimed to define the fluoride concentration in drinking waters of volcanic origin and compare the sensitivity of urine and nail clippings as biomarkers for fluoride exposure in adults and children. Samples of drinking water from four villages in São Miguel Island (Azores) were used and the fluoride concentration was determined, as well the fluoride content in urine and toenails clippings from 66 children and 63 adults from these villages. A validated diet questionnaire, assessing sources of fluoride, was recorded for each participant. The fluoride determination in urine and nail clipping samples was made using a fluoride-specific electrode. A positive correlation was found between the fluoride daily intake and fluoride content in children urine (rs = 0.475; p < 0.001) and in their nail clippings (rs = 0.475; p < 0.001), while in adult women, the fluoride daily intake correlated positively with fluoride content nail clippings (rs = 0.495, p < 0.001). This reveals that nail clippings are more reliable as biomarkers of chronic exposure to fluoride than urine for populations of different ages (children vs. adults). Furthermore, nail clippings are more suitable than urine fluoride levels to assess long term exposure to fluoride in areas where the exposure to fluoride in drinking water is considered within, or slightly above, the recommended legal values.

  7. Groundwater flow in a volcanic-sedimentary coastal aquifer: Telde area, Gran Canaria, Canary Islands, Spain

    Cabrera, M. C.; Custodio, E.

    Groundwater conditions in a 75- km2 coastal area around the town of Telde in eastern Gran Canaria island have been studied. Pliocene to Recent volcanic materials are found, with an intercalated detrital formation (LPDF), which is a characteristic of the area. Groundwater development has become intensive since the 1950s, mostly for intensive agricultural irrigation and municipal water supply. The LPDF is one order of magnitude more transmissive and permeable than the underlying Phonolitic Formation when median values are compared (150 and 15 m2 day-1 5 and 0.5 m day-1, respectively). These two formations are highly heterogeneous and the ranges of expected well productivities partly overlap. The overlying recent basalts constituted a good aquifer several decades ago but now are mostly drained, except in the southern areas. Average values of drainable porosity (specific yield) seem to be about 0.03 to 0.04, or higher. Groundwater development has produced a conspicuous strip where the watertable has been drawn down as much as 40 m in 20 years, although the inland watertable elevation is much less affected. Groundwater reserve depletion contributes only about 5% of ed water, and more than 60% of this is transmitted from inland areas. Groundwater discharge into the sea may still be significant, perhaps 30% of total inflow to the area is discharged to the sea although this value is very uncertain. Les conditions de gisement de l'eau souterraine d'une région de 75 km2 de la côte Est de l'île de la Grande Canarie (archipel des Canaries), dans le secteur de Telde, ont été étudiées, en utilisant seulement les données fournies par les puits d'exploitation existants. Les matériaux volcaniques, d'âge Pliocène à sub-actuel, sont séparés par une formation détritique (FDLP), qui constitue la principale singularité de cette région. L'exploitation de l'eau souterraine est devenue intensive à partir de 1950, principalement pour des besoins d'irrigation (agriculture

  8. Teleseismic tomography of the Campanian volcanic area and surrounding Apenninic belt

    De Gori, P.; Cimini, G. B.; Chiarabba, C.; De Natale, G.; Troise, C.; Deschamps, A.


    The three-dimensional P-velocity structure of the crust and upper mantle beneath the Vesuvius volcano and the surrounding Apenninic belt is derived by teleseismic tomography to describe the deep volcanic structure and its relationship with the Adriatic lithosphere subducting beneath the belt. The data consist of 1615 P and PKP travel times derived from 135 teleseismic events. We merged the data recorded by the stations of the Italian Seismic Network located on the southern Apennines with stations deployed in a temporary broad-band experiment around Vesuvius volcano (BROADVES). The traveltime residuals, computed with respect to the IASP91 1D reference model, are inverted using the ACH code. The 3D velocity structure shows a lower crust characterised by strong lateral heterogeneities with velocity perturbations ranging from -5 to +5%. In the lower crust along the Tyrrhenian margin, low-velocity anomalies are found beneath the volcanic complexes, suggesting the presence of deep crustal magmatic reservoirs. An almost continuous high-velocity body is reconstructed in the upper mantle beneath the Apenninic belt from 65 down to 285 km depth. This high-velocity anomaly is interpreted as the signature of the Adriatic lithosphere subducting westward toward the back-arc Tyrrhenian basin. The low-velocity anomaly in the crust beneath Vesuvius, located above the high-velocity zone dipping in the mantle, may indicate that magma is generated by the subducting slab and rises to lower crustal depths where it is stored.

  9. Volcano-tectonic structures, gravity and helium in geothermal areas of Tuscany and Latium (Vulsini volcanic district), Italy

    Di, Filippo M.; Lombardi, S.; Nappi, G.; Reimer, G.M.; Renzulli, A.; Toro, B.


    Since the early 1980s, geological and structural mapping, gravity, and helium soil-gas studies have been performed in the eastern sector of the Vulsini Volcanic District (Roman Magmatic Province) in an attempt to locate potential geothermal reservoirs. This area is characterised by an anomalous geothermal gradient of > 100??C/km, and by widespread hydrothermal mineralization, thermal springs, high gas fluxes, and fossil and current travertine deposits. The results of these surveys indicate the existence of a number of fault systems, with N-S and E-W structures that appear to be superimposed on older NW-SE and NE-SW features. Comparison of the results of the various studies also reveals differences in permeability and potential reservoir structures at depth.Since the early 1980s, geological and structural mapping, gravity, and helium soil-gas studies have been performed in the eastern sector of the Vulsini Volcanic District (Roman Magmatic Province) in an attempt to locate potential geothermal reservoirs. This area is characterised by an anomalous geothermal gradient of > 100??C/km, and by widespread hydrothermal mineralization, thermal springs, high gas fluxes, and fossil and current travertine deposits. The results of these surveys indicate the existence of a number of fault systems, with N-S and E-W structures that appear to be superimposed on older NW-SE and NE-SW features. Comparison of the results of the various studies also reveals differences in permeability and potential reservoir structures at depth.

  10. K-Ar dating, whole-rock and Sr-Nd isotope geochemistry of calc-alkaline volcanic rocks around the Gümüşhane area: implications for post-collisional volcanism in the Eastern Pontides, Northeast Turkey

    Aslan, Zafer; Arslan, Mehmet; Temizel, İrfan; Kaygusuz, Abdullah


    Volcanic rocks from the Gümüşhane area in the southern part of the Eastern Pontides (NE Turkey) consist mainly of andesitic lava flows associated with tuffs, and rare basaltic dykes. The K-Ar whole-rock dating of these rocks range from 37.62 ± 3.33 Ma (Middle Eocene) to 30.02 ± 2.84 Ma (Early Oligocene) for the andesitic lava flows, but are 15.80 ± 1.71 Ma (Middle Miocene) for the basaltic dykes. Petrochemically, the volcanic rocks are dominantly medium-K calc-alkaline in composition and show enrichment of large ion lithophile elements, as well as depletion of high field strength elements, thus revealing that volcanic rocks evolved from a parental magmas derived from an enriched mantle source. Chondrite-normalized rare-earth element patterns of the volcanic rocks are concave upwards with low- to-medium enrichment (LaCN/LuCN = 3.39 to 12.56), thereby revealing clinopyroxene- and hornblende-dominated fractionations for andesitic-basaltic rocks and tuffs, respectively. The volcanic rocks have low initial 87Sr/86Sr ratios (0.70464 to 0.70494) and ɛNd(i) values (+1.11 to +3.08), with Nd-model ages (TDM) of 0.68 to 1.02 Ga, suggesting an enriched lithospheric mantle source of Proterozoic age. Trace element and isotopic data, as well as the modelling results, show that fractional crystallization and minor assimilation played an important role in the evolution of the volcanic rocks studied. The Eocene to Miocene volcanism in the region has resulted from lithospheric delamination and the associated convective thinning of the mantle, which led to the partial melting of the subduction-metasomatized lithospheric mantle.

  11. Geochemical Signature of Mesozoic Volcanic and Granitic Rocks in Madina Regency Area, North Sumatra, Indonesia, and its Tectonic Implication

    Iskandar Zulkarnain


    Full Text Available samples consisting of two Permian-Triassic basalts, two Triassic-Jurassic granitic rocks, and a Miocene andesite were collected from the Madina Regency area in North Sumatra that is regionally situated on the West Sumatra Block. Previous authors have proposed three different scenarios for the geological setting of West Sumatra Permian Plutonic-Volcanic Belt, namely an island-arc, subduction related continental margin arc, and continental break-up. Petrographic analysis of the Mesozoic basaltic samples indicates that they are island-arcs in origin; however their trace element spider diagram patterns (Rock/MORB ratio also show the character of back-arc marginal basin, besides the island-arc. Furthermore, their REE spider diagram patterns (Rock/ Chondrite ratio clearly reveal that they were actually generated in a back-arc marginal basin tectonic setting. Meanwhile, the two Mesozoic granitic rocks and the Miocene andesite reflect the character of an active continental margin. Their spider diagram patterns show a significant enrichment on incompat- ible elements, usually derived from fluids of the subducted slab beneath the subduction zone. The high enrichment on Th makes their plots on Ta/Yb versus Th/Yb diagram are shifted to outside the active continental margin field. Although the volcanic-plutonic products represent different ages, their La/Ce ratio leads to a probability that they have been derived from the same magma sources. This study offers another different scenario for the geological setting of West Sumatra Permian Plutonic-Volcanic Belt, where the magmatic activities started in a back-arc marginal basin tectonic setting during the Permian-Triassic time and changed to an active continental margin during Triassic to Miocene. The data are collected through petrographic and chemical analyses for major, trace, and REE includ- ing literature studies.  

  12. Geochemical Signature of Mesozoic Volcanic and Granitic Rocks in Madina Regency Area, North Sumatra, Indonesia, and its Tectonic Implication

    Iskandar Zulkarnain


    Full Text Available samples consisting of two Permian-Triassic basalts, two Triassic-Jurassic granitic rocks, and a Miocene andesite were collected from the Madina Regency area in North Sumatra that is regionally situated on the West Sumatra Block. Previous authors have proposed three different scenarios for the geological setting of West Sumatra Permian Plutonic-Volcanic Belt, namely an island-arc, subduction related continental margin arc, and continental break-up. Petrographic analysis of the Mesozoic basaltic samples indicates that they are island-arcs in origin; however their trace element spider diagram patterns (Rock/MORB ratio also show the character of back-arc marginal basin, besides the island-arc. Furthermore, their REE spider diagram patterns (Rock/ Chondrite ratio clearly reveal that they were actually generated in a back-arc marginal basin tectonic setting. Meanwhile, the two Mesozoic granitic rocks and the Miocene andesite reflect the character of an active continental margin. Their spider diagram patterns show a significant enrichment on incompat- ible elements, usually derived from fluids of the subducted slab beneath the subduction zone. The high enrichment on Th makes their plots on Ta/Yb versus Th/Yb diagram are shifted to outside the active continental margin field. Although the volcanic-plutonic products represent different ages, their La/Ce ratio leads to a probability that they have been derived from the same magma sources. This study offers another different scenario for the geological setting of West Sumatra Permian Plutonic-Volcanic Belt, where the magmatic activities started in a back-arc marginal basin tectonic setting during the Permian-Triassic time and changed to an active continental margin during Triassic to Miocene. The data are collected through petrographic and chemical analyses for major, trace, and REE includ- ing literature studies.  

  13. Comparison of the chemical composition of PM10 and PM2.5 particles collected in urban environments and volcanic areas of metropolitan Costa Rica

    Jorge Herrera


    Full Text Available PM10 and PM2,5 were sampled simultaneously in urban and volcanic environments in the Metropolitan Area of Costa Rica from October to November 2012. Higher mass concentrations (42-29 μgm-3 of PM10 and PM2,5 were found at industrial and commercial areas with high traffic flow (La Uruca, Heredia and Belen compared with those found in the volcanic areas. The daily concentrations of PM10 and PM2,5 obtained in the Poas Volcano ranged from 3 -14 μgm-3 and 2-11 μgm-3, respectively. However the acidity of the collected particles in the Poas volcano was higher than those sampled in urban environments probably due to a lower occurrence rate of neutralization. The contribution of secondary ions was more important to the volcanic PM10 composition (around 40%, unlike the PM10 collected in urban areas.

  14. Age and location of volcanic centers less than or equal to 3. 0 Myr old in Arizona, New Mexico and the Trans-Pecos Area of West Texas

    Aldrich, M.J.; Laughlin, A.W.


    This map is one of a series of maps designed for hot dry rock geothermal assessment in Arizona, New Mexico, and the Trans-Pecos area of west Texas. The 3.0 m.y. cutoff age was selected because original heat has probably largely dissipated in older rocks. The location of volcanic centers is more important to geothermal resource assessment than the location of their associated volcanic rocks; however, ages have been determined for numerous flows far from their source. Therefore, the distribution of all volcanic rocks less than or equal to 3.0 m.y. old, for which there is at least one determined age, are shown. Location of the volcanic vents and rocks were taken from Luedke and Smith (1978).

  15. Slab window-related magmatism from southernmost South America: the Late Miocene mafic volcanics from the Estancia Glencross Area (˜52°S, Argentina Chile)

    D'Orazio, M.; Agostini, S.; Innocenti, F.; Haller, M. J.; Manetti, P.; Mazzarini, F.


    The Estancia Glencross Area (EGA) volcanic rocks form a series of five isolated buttes located at the southern end (˜52°S) of the discontinuous belt of Cenozoic basaltic lava formations occurring in the extra-Andean Patagonia. EGA volcanics are subalkaline basalts and basaltic andesites erupted at 8.0-8.5 Ma in a region closely behind the Andean Cordillera. EGA volcanism predated by about 4-5 my the onset of the volcanism in the nearby Pali Aike Volcanic Field, which produced highly primitive, alkaline lavas. Incompatible trace-element distributions and Sr-Nd isotope compositions of EGA rocks are those typical of within-plate OIB-type basalts and are indicative of minimal interaction of sub-lithospheric magmas with enriched reservoirs. The geochemical characteristics of EGA volcanics, as well as their age and location are consistent with a model of slab window opening beneath this region. The high silica content and the garnet signature of the estimated EGA primary magma are explained by a two-stage process involving the initial production of melts from a garnet lherzolite source followed by the reaction of these melts with harzburgite country rocks during their ascent through the mantle lithosphere. The melt/harzburgite reaction, favoured by a slow melt ascent rate, as well as the low magma production at EGA, are likely related to the dominantly compressive stress regime operating in this area during Late Miocene.

  16. Ar-Ar geochronology of Late Mesozoic volcanic rocks from the Yanji area,NE China and tectonic implications

    LI ChaoWen; GUO Feng; FAN WeiMing; GAO XiaoFeng


    Ar-Ar dating results of late Mesozoic-Cenozoic volcanic rocks from the Yanji area, NE China provide a new volcano-sedimentary stratigraphic framework. The previously defined "Triassic-Jurassic" volcanic rocks(including those from Sanxianling, Tuntianying, Tianqiaoling and Jingouling Fms.)were erupted during 118-106Ma,corresponding to Early Cretaceous. The new eruption age span is slightly younger than the main stage(130-120 Ma)of the extensive magmatism in the eastern Central Asian Orogenic Belt and its adjacent regions. Subduction-related adakites occurring in the previously defined Quanshuicun Fm. Were extruded at ca.55 Ma. Based on these new Ar-Ar ages, the late Mesozoic to Palaeocene volcano-sedimentary sequences is rebuilt as:Tuopangou Fm., Sanxianling/Tuntianying Fm.(118-115 Ma),Malugou/Tianqiaoling Fm.(K1),Huoshanyan/Jingouling Fm.(108-106 Ma),Changcai Fm.(K2),Quanshuicun Fm.(~55 Ma)and Dalazi Fm. Our results suggest that subduction of the Palaeo-Pacific Ocean beneath the East Asian continental margin occurred during 106to 55 Ma. Consistent with the paleomagnetic observations and magmatic records which indicated that the Izanagi-Farallon ridge subduction beneath the southwestern Japan took place during 95-65 Ma.

  17. Ar-Ar geochronology of Late Mesozoic volcanic rocks from the Yanji area, NE China and tectonic implications


    Ar-Ar dating results of late Mesozoic-Cenozoic volcanic rocks from the Yanji area, NE China provide a new volcano-sedimentary stratigraphic framework. The previously defined “Triassic-Jurassic” volcanic rocks (including those from Sanxianling, Tuntianying, Tianqiaoling and Jingouling Fms.) were erupted during 118―106 Ma, corresponding to Early Cretaceous. The new eruption age span is slightly younger than the main stage (130―120 Ma) of the extensive magmatism in the eastern Central Asian Orogenic Belt and its adjacent regions. Subduction-related adakites occurring in the previously defined Quanshuicun Fm. were extruded at ca. 55 Ma. Based on these new Ar-Ar ages, the late Mesozoic to Palaeocene volcano-sedimentary sequences is rebuilt as: Tuopangou Fm., Sanxianling/Tuntianying Fm. (118―115 Ma), Malugou/Tianqiaoling Fm. (K1), Huoshanyan/Jingouling Fm. (108―106 Ma), Changcai Fm. (K2), Quanshuicun Fm. (~55 Ma) and Dalazi Fm. Our results suggest that subduction of the Pa- laeo-Pacific Ocean beneath the East Asian continental margin occurred during 106 to 55 Ma, consistent with the paleomagnetic observations and magmatic records which indicated that the Izanagi-Farallon ridge subduction beneath the southwestern Japan took place during 95―65 Ma.

  18. 7 CFR 1780.11 - Service area requirements.


    ..., maintenance, debt service, and reserve requirements. Such guarantees from developers will meet the... 7 Agriculture 12 2010-01-01 2010-01-01 false Service area requirements. 1780.11 Section 1780.11... AGRICULTURE (CONTINUED) WATER AND WASTE LOANS AND GRANTS General Policies and Requirements § 1780.11 Service...

  19. Requirements and Implementation Feasibility for a CubeSat Thermal Infrared Imaging System to Monitor the Structure of Volcanic Ash Clouds

    Thorsen, D.; Carroll, R.; Webley, P.; Hawkins, J.


    The 2010 eruption of the Eyjafjallajökull volcano in Iceland caused the cancellation of approximately 108,000 flights over an 8-day period, disrupted air traffic worldwide, and cost the airline industry more than $400 million per day. The inconvenience and economic impact of this and similar events, such as Puyehue-Cordon-Caulle in 2011, have heightened the interest in developing improved satellite remote sensing techniques for monitoring volcanic plumes and drifting clouds. For aviation safety, the operational/research community has started to move towards classifying the concentrations within volcanic plumes and clouds. Additionally, volcanic ash transport and dispersion (VATD) models are often used for forecasting ash cloud locations and they require knowledge of the structure of the erupting column to improve their ash simulations and also downwind 3-D maps of the ash cloud to calibrate/validate their modeling output. Existing remote sensing satellites utilize a brightness temperature method with thermal infrared (TIR) measurements from 10 - 12 μm to determine mass loading of volcanic ash along a single line of sight, but they have infrequent revisit times and they cannot resolve the three-dimensional structure of the ash clouds. A cluster of CubeSats dedicated to the monitoring of volcanic ash and plumes could provide both more frequent updates and the multi-aspect images needed to resolve the density structure of volcanic ash clouds and plumes. In this presentation, we discuss the feasibility and requirements for a CubeSat TIR imaging system and the associated on-board image processing that would be required to monitor the structure of volcanic ash clouds from Low Earth Orbit.

  20. Hummock alignment in Japanese volcanic debris avalanches controlled by pre-avalanche slope of depositional area

    Yoshida, Hidetsugu


    This paper investigates the relationship of hummock orientation to the flow dynamics of volcanic debris avalanches. There are opposing views on whether hummocks are systematically aligned along debris avalanche paths, or not. To investigate this geomorphologically fundamental question, I investigated hummock orientation for six Japanese debris avalanches of two simple styles: four "freely spreading" debris avalanches, and two "valley-filling" debris avalanches. Quantitative GIS-based data analysis revealed that hummock orientation along the avalanche flow path alternated between dominantly parallel to and dominantly perpendicular to the flow direction. These changes of alignment reflect dynamic changes of the local stress field within the avalanche, alternating between extensional and compressional in response to changes of the slope of the pre-avalanche ground surface. Changes of hummock alignment from perpendicular to parallel indicate that the local stress regime has changed from compressional to extensional. Conversely, changes of hummock alignment from parallel to perpendicular indicate that the local stress regime has changed from extensional to compressional. Thus, this research demonstrated a clear relationship between hummock orientation and dynamic changes of stress regime within avalanches that are related to changes of the slope of the pre-avalanche ground surface.

  1. Marine geophysical methods for archaeological investigation of volcanic and bradyseismic areas

    F. Giordano


    Full Text Available The aim of this work was to test several geophysical methods for the identification and study of submerged prehistorical coastlines and archaeological sites. This research program was carried out in collaboration with the <> in the Gulf of Pozzuoli and dealt in particular with the bathymetric strips extending from - 5 m to - 50 m Within these strips we identified the coastline dating from the Rornan period. former beach boundaries associated with the vertical movements of the earth's surface caused by seismic-volcanic activity, and the variations in sea level following the climactic changes throughout the last 15000 years. The UNIBOOM system was used for this part of the programme, perinittiilg the identification of several coastlines and submerged beaches lying at different levels. The use of a modern Side Scan Sonar - for the morphological invesdgation of the sea bed - in a zone which had been the object of numerous archaeological surveys in the past, permitted previously unknown structures near the Lacuus Baianus to be identified. Other features worth pointing out include the operating speed of the system (15000 m'lfirst minute approx and its observation capacity in cloudy waters compared to visible radiation, as well as its ability to penetrate thin layers of mud which generally impede direct underwater observation.

  2. Volcano-tectonic structures, gravity and helium in geothermal areas of Tuscany and Latium (Vulsini volcanic district), Italy

    Di Filippo, Michele; Lombardi, Salvatore; Toro, Beniamino [Universita di Roma ' La Sapienza' , Dip. di Scienze della Terra, Roma (Italy); Nappi, Giovanni; Renzulli, Alberto [Universita di Urbino, Ist. di Mineralogia e Petrologia, Urbino (Italy); Reimer, G. Michael [U.S. Geological Survey, Federal Center, Denver, CO (United States)


    Since the early 1980s, geological and structural mapping, gravity, and helium soil-gas studies have been performed in the eastern sector of the Vulsini Volcanic District (Roman Magmatic Province) in an attempt to locate potential geothermal reservoirs. This area is characterised by an anomalous geothermal gradient of 100degC/km, and by widespread hydrothermal mineralisation, thermal springs, high gas fluxes, and fossil and current travertine deposits. The results of these surveys indicate the existence of a number of fault systems, with N-S and E-W structures that appear to be superimposed on older NW-SE and NE-SW features. Comparison of the results of the various studies also reveals differences in permeability and potential reservoir structures at depth. (Author)

  3. Improved techniques in data analysis and interpretation of potential fields: examples of application in volcanic and seismically active areas

    G. Florio


    Full Text Available Geopotential data may be interpreted by many different techniques, depending on the nature of the mathematical equations correlating specific unknown ground parameters to the measured data set. The investigation based on the study of the gravity and magnetic anomaly fields represents one of the most important geophysical approaches in the earth sciences. It has now evolved aimed both at improving of known methods and testing other new and reliable techniques. This paper outlines a general framework for several applications of recent techniques in the study of the potential methods for the earth sciences. Most of them are here described and significant case histories are shown to illustrate their reliability on active seismic and volcanic areas.

  4. Use of precipitation and groundwater isotopes to interpret regional hydrology on a tropical volcanic island: Kilauea volcano area, Hawaii

    Scholl, M.A.; Ingebritsen, S.E.; Janik, C.J.; Kauahikaua, J.P.


    Isotope tracer methods were used to determine flow paths, recharge areas, and relative age for groundwater in the Kilauea volcano area of the Island of Hawaii. A network of up to 66 precipitation collectors was emplaced in the study area and sampled twice yearly for a 3-year period. Stable isotopes in rainfall show three distinct isotopic gradients with elevation, which are correlated with trade wind, rain shadow, and high- elevation climatological patterns. Temporal variations in precipitation isotopes are controlled more by the frequency of storms than by seasonal temperature fluctuations. Results from this study suggest that (1) sampling network design must take into account areal variations in rainfall patterns on islands and in continental coastal areas and (2) isotope/elevation gradients on other tropical islands may be predictable on the basis of similar climatology. Groundwater was sampled yearly in coastal springs, wells, and a few high-elevation springs. Areal contrasts in groundwater stable isotopes and tritium indicate that the volcanic rift zones compartmentalize the regional groundwater system, isolating the groundwater south of Kilauea's summit and rift zones. Part of the Southwest Rift gone appears to act as a conduit for water from higher elevation, but there is no evidence for downrift flow in the springs and shallow wells sampled in the lower East Rift Zone.

  5. 2D resistivity survey in complex geological structure area. Application to the volcanic area; Fukuzatsuna chishitsu kozo chiiki ni okeru hiteiko nijigen tansa. Kazangan chiiki deno tekiorei

    Asakawa, S.; Ikuma, T.; Tanifuji, R. [DIA Consultants Co. Ltd., Tokyo (Japan)


    Introduced herein is an application of 2D resistivity survey to a volcanic rock area where the survey result is difficult to interpret because of its complex geological structure. In a dam site survey, main problems involve the permeability of water through faults and weathered, altered zones. At this site, a 2D resistivity survey was conducted, a 2D geological structure was deduced from the resistivity section, and the result was examined. It was found that resistivity distribution was closely related to hydrographic factors, but no obvious correlation was detected between rock classes and R, Q, and D. In conducting investigations into a section planned for a highway tunnel, it was learned that the problem was a volcanic ash layer to collapse instantly upon absorbing water, and the distribution of the ash layer, not to be disclosed by boring, was subjected to a 2D resistivity survey. The survey was conducted into the structure above where the tunnel would run, and further into the face, and studies were made about what layer was reflected by the resistivity distribution obtained by analysis. The result of the analysis agreed with the details of the layer that was disclosed afterward. 4 figs., 1 tab.

  6. Toward better application of minimum area requirements in conservation planning

    Pe’er, G.; Tsianou, M.A.; Franz, K.W.; Matsinos, Y.G.; Mazaris, A.D.; Storch, D.; Kopsova, L.; Verboom, J.; Baguette, M.; Stevens, V.M.; Henle, K.


    The Minimum Area Requirements (MAR) of species is a concept that explicitly addresses area and therefore can be highly relevant for conservation planning and policy. This study compiled a comprehensive database of MAR estimates from the literature, covering 216 terrestrial animal species from 80

  7. Geochemistry and tectonomagatic setting of Tertiary volcanic rocks of the Kangan area, northeast of Sarbisheh, southern Khorasan

    Mahshid Malekian Dastjerdi


    Full Text Available Introduction The study area is located 12km away from the north east of Sarbisheh at the eastern border of the Lut block (Karimpour et al., 2011; Richards et al., 2012. The magmatic activity in the Lut blockhas begun in the middle Jurassic (165-162 Ma and reached its peak in the Tertiary age (Jung et al., 1983; Karimpour et al., 2011. Volcanic and subvolcanic rocks in the Tertiary age cover over half of the Lut block with up to 2000 m thickness and they were formed due to subduction prior to the collision of the Arabian and Asian plates (Jung et al., 1983; Karimpour et al., 2011. In the Kangan area, the basaltic lavas cropped out beyond the above intermediate to acid volcanic rocks. In this area, bentonite and perlite deposits have an economic importance. The main purpose of this paper is to present a better understanding of the tectono-magmatic settings of volcanic rocks in the northeast of Sarbisheh, east of Iran based on their geochemical characteristics. Materials and methods Fifteen samples were analyzed for major elements by inductively coupled plasma (ICP technologies and trace elements by using inductively coupled plasma mass spectrometry (ICP-MS, following a lithium metaborate/tetraborate fusion and nitric acid total digestion, at the Acme laboratories, Vancouver, Canada. Results The Kangan area is located at the northeast of Sarbishe, Southern Khorasan and the eastern border of the Lut block. In this area, basaltic lavas have cropped out above intermediate to acid lavas such as andesite, dacite, rhyolite (sometimes perlitic .The main minerals in the basalt are plagioclase, olivine and pyroxene, in andesite contain plagioclase, pyroxene, biotite and amphibole and in acid rocks include plagioclase, quartz, sanidine, biotite and amphibole. Intermediate to acid rocks have medium to high-K calc-alkaline nature and basalt is alkaline. Enrichment in LREE relative to HREE (Ce/Yb= 21.14-28.7, high ratio of Zr/Y(4.79- 10.81, enrichment in LILE

  8. International Studies of Hazardous Groundwater/Surface Water Exchange in the Volcanic Eruption and Tsunami Affected Areas of Kamchatka

    Kontar, Y. A.; Gusiakov, V. K.; Izbekov, P. E.; Gordeev, E.; Titov, V. V.; Verstraeten, I. M.; Pinegina, T. K.; Tsadikovsky, E. I.; Heilweil, V. M.; Gingerich, S. B.


    During the US-Russia Geohazards Workshop held July 17-19, 2012 in Moscow, Russia the international research effort was asked to identify cooperative actions for disaster risk reduction, focusing on extreme geophysical events. As a part of this recommendation the PIRE project was developed to understand, quantify, forecast and protect the coastal zone aquifers and inland water resources of Kamchatka (Russia) and its ecosystems affected by the November 4, 1952 Kamchatka tsunami (Khalatyrka Beach near Petropavlovsk-Kamchatskiy) and the January 2, 1996 Karymskiy volcano eruption and the lake tsunami. This project brings together teams from U.S. universities and research institutions located in Russia. The research consortium was briefed on recent technical developments and will utilize samples secured via major international volcanic and tsunami programs for the purpose of advancing the study of submarine groundwater discharge (SGD) in the volcanic eruption and tsunami affected coastal areas and inland lakes of Kamchatka. We plan to accomplish this project by developing and applying the next generation of field sampling, remote sensing, laboratory techniques and mathematical tools to study groundwater-surface water interaction processes and SGD. We will develop a field and modeling approach to define SGD environment, key controls, and influence of volcano eruption and tsunami, which will provide a framework for making recommendations to combat contamination. This is valuable for politicians, water resource managers and decision-makers and for the volcano eruption and tsunami affected region water supply and water quality of Kamchatka. Data mining and results of our field work will be compiled for spatial modeling by Geo-Information System (GIS) using 3-D Earth Systems Visualization Lab. The field and model results will be communicated to interested stakeholders via an interactive web site. This will allow computation of SGD spatial patterns. In addition, thanks to the

  9. Geologic Investigations Spurred by Analog Testing at the 7504 Cone-Sp Mountain Area of the San Francisco Volcanic Field

    Bleacher, J. E.; Eppler, D. B.; Needham, D. H.; Evans, C. A.; Skinner, J. A.; Feng, W.


    The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

  10. Geologic Investigations Spurred by Analog Testing at the 7504 Cone-SP Mountain Area of the San Francisco Volcanic Field

    Eppler, Dean B.


    The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

  11. Minimizing the area required for time constants in integrated circuits

    Lyons, J. C.


    When a medium- or large-scale integrated circuit is designed, efforts are usually made to avoid the use of resistor-capacitor time constant generators. The capacitor needed for this circuit usually takes up more surface area on the chip than several resistors and transistors. When the use of this network is unavoidable, the designer usually makes an effort to see that the choice of resistor and capacitor combinations is such that a minimum amount of surface area is consumed. The optimum ratio of resistance to capacitance that will result in this minimum area is equal to the ratio of resistance to capacitance which may be obtained from a unit of surface area for the particular process being used. The minimum area required is a function of the square root of the reciprocal of the products of the resistance and capacitance per unit area. This minimum occurs when the area required by the resistor is equal to the area required by the capacitor.

  12. Petrogenesis of the Miocene volcanism along the İzmir-Balıkesir Transfer Zone in western Anatolia, Turkey: Implications for origin and evolution of potassic volcanism in post-collisional areas

    Ersoy, Yalçın E.; Helvacı, Cahit; Uysal, İbrahim; Karaoğlu, Özgür; Palmer, Martin R.; Dindi, Fulya


    The Miocene volcanic rocks along the İzmir-Balıkesir Transfer Zone along the western margin of the Menderes Core Complex (MCC) in western Anatolian Volcanic Province (WAVP), where strike-slip deformation is dominant, comprise: (Group 1) early-middle Miocene high-K to shoshonitic rocks with high-Mg# and relatively low SiO2, (Group 2) middle Miocene phonolitic rocks with low-Mg# and intermediate SiO2, (Group 3) early-middle Miocene medium- to high-K series from andesites to rhyolites, (Group 4) middle Miocene rhyolites with distinct trace element compositions; and (Group 5) late Miocene high-MgO basalts, K-trachybasalts and (Group 6) late Miocene high-MgO basaltic andesites. The geochemical features of these rocks are comparable with the other Oligocene to Miocene volcanic rocks, but differ from the Eocene volcanic rocks in WAVP. The geochemical features of the most primitive early-middle Miocene Group 1 rocks indicate that they were derived from an anomalously metasomatized lithospheric mantle. The mineralogical and geochemical properties of garnet-amphibole peridotite from the Ulten Zone (UZP), Eastern Alps, which is thought to represent a fossil metasomatic mantle wedge contaminated by continental subduction, is similar to the model mantle composition previously proposed for the genesis of the mafic rocks. Together with the presence of Eocene to early Miocene continental subduction beneath the Aegean-west Anatolia region, this strongly suggests that continental subduction was an important factor in the genesis of the high-MgO shoshonitic to ultrapotassic volcanism in this post-collisional area. The origin of the Group 3 andesitic to rhyolitic rocks includes; (1) lower crustal melting, (2) mixing between lower crustally-derived and mantle-derived melts, and (3) FC-AFC processes. The late Miocene Group 5 and 6 rocks, however, derived from a more depleted mantle source, indicating that the mantle became depleted over time. The rhyolites of Group 4 are most probably

  13. Thermography of volcanic areas on Piton de la Fournaise, Reunion Island : Mapping surface properties and possible detection of convective air flow within volcanic debris

    Antoine, R.; Baratoux, D.; Rabinowicz, M.; Saracco, G.; Bachelery, P.; Staudacher, T.; Fontaine, F.


    We report on the detection of air convection in a couple of quasi circular cavities forming the 300 years old volcanically inactive cone of Formica Leo (Piton de la Fournaise, Reunion Island) [1]. Infrared thermal images of the cone have been acquired in 2006 from a hand held camera at regular time interval during a complete diurnal cycle. During night and dawn, the data display hot rims and cold centers. Both the conductivity contrasts of the highly porous soils filling the cavities and their 30° slopes are unable to explain the systematic rim to center temperature drop. Accordingly, this signal could be attributed to an air convection dipping inside the highly porous material at the center of each cavity, then flowing upslope along the base of the soil layer, before exiting it along the rims. Anemometrical and electrical data acquired in 2007 allow for the first time the direct detection of this air flow on the field: dipping gas velocities are measured at the center of the cone and self-potentials anomalies [2] generated by the humid air flow in the porous medium are detected. To quantify this process, we present 2D/3D numerical models of air convection in a sloped volcanic soil with a surface temperature evolving between day and night and taking into account electrical phenomena created by the air flow. At this present stage, this work constitutes a first step to investigate the deep structure of the active caldera of Bory-Dolomieu. The detection of the air flow at the surface could be of paramount importance for the understanding of volcanic hazards of the Reunion volcano. [1] Antoine et. al, submitted to G-Cubed [2] Darnet, PhD, Université Louis Pasteur (2003)

  14. Draft Genome Sequence of the Novel Thermoacidophilic Archaeon Acidianus copahuensis Strain ALE1, Isolated from the Copahue Volcanic Area in Neuquen, Argentina.

    Urbieta, M Sofía; Rascovan, Nicolás; Castro, Camila; Revale, Santiago; Giaveno, M Alejandra; Vazquez, Martín; Donati, Edgardo R


    Acidianus copahuensis is a recently characterized thermoacidophilic archaeon isolated from the Copahue volcanic area in Argentina. Here, we present its draft genome sequence, in which we found genes involved in key metabolic pathways for developing under Copahue's extreme environmental conditions, such as sulfur and iron oxidation, carbon fixation, and metal tolerance.

  15. Appraisal and evolution of hydrochemical processes from proximity basalt and granite areas of Deccan Volcanic Province (DVP) in India

    Sonkamble, Sahebrao; Sahya, Ashalata; Mondal, N. C.; Harikumar, P.


    SummaryThis paper deals with a systematic hydrochemical study carried out at proximity basalt and granite areas of Deccan Volcanic Province (DVP) in India to assess groundwater quality and evaluate the hydrochemical processes. A total of 40 groundwater samples were collected equally from these areas and analyzed. Results showed that the groundwaters rich in alkaline earth in the basalt and alkali rich element in the granite. The dominancy of cations was observed as Ca2+ > Mg2+ > Na+ > K+ in the basalt and Na+ > Mg2+ > K+ > Ca2+ in the granite, whereas anions as HCO3->Cl>SO42- and Cl>HCO3->SO42-, respectively. Hydrochemical processes were identified with the helps of ion exchange, carbonate weathering and dissolution, multiple ionic ratios, and silicate weathering, which shown the predominance of carbonate, dolomite, calcite and silicate (anorthite) weathering in basalt, but in granite, silicate (alkali feldspar) weathering was dominated. Factor analysis also showed that there were multiple processes acting on groundwaters, were separated from the main cluster. Salinity, Sodium Absorption Ratio (SAR), Soluble Sodium Percentage (SSP), Residual Sodium Carbonate (RSC), Kelley's Ratio (KR) and Permeability Index (PI) in well samples showed that groundwater in basalt was more suitable for irrigation purposes. Further, a digital elevation model (DEM) was generated using Global mapper (8.0 version) software, which aided to decipher the thickness of basalt trap, and vertical transition zone of basaltic (trap) and granitic (basement) aquifer at this DVP comprising with the well depths and groundwater chemistry.

  16. Cenozoic volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, China: Petrochemical evidence for partial melting of the mantle-crust transition zone

    LAI Shaocong; QIN Jiangfeng; LI Yongfeng; LIU Xin


    Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%-62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10-13, (La/Yb)N=15-19, and show a weak negative Eu anomaly with δEu=0.71-0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23-3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau.

  17. Cryptoexplosive Breccias in Nanjing -Wuhu Volcanic Area:Geological Characteristics and Control on Mineralization


    Geological and geochemical characters are discussed for the breccias in the Nanjing -Wuhu area,with special reference to their cryptoexplosive origin.The close association of mineralization,particularly of iron,with the breccias has been evaluated in terms of geothermal and geochemical evidence.A suc-cessful example in using the breccias as a prospecting indicator is illustrated in this paper.

  18. SHRIMP Geochronology of Volcanics of the Zhangjiakou and Yixian Formations, Northern Hebei Province, with a Discussion on the Age of the Xing'anling Group of the Great Hinggan Mountains and Volcanic Strata of the Southeastern Coastal Area of China

    NIU Baogui; HE Zhengjun; SONG Biao; REN Jishun; XIAO Liwei


    A zircon U-Pb geochronological study on the volcanic rocks reveals that both of the Zhangjiakou and Yixian Formations, northern Hebei Province, are of the Early Cretaceous, with ages of 135-130 Ma and 129-120 Ma,respectively. It is pointed out that the ages of sedimentary basins and volcanism in the northern Hebei -western Liaoning area become younger from west to east, i. e. the volcanism of the Luanping Basin commenced at c. 135 Ma, the Luotuo Mount area of the Chengde Basin c. 130 Ma, and western Liaoning c. 128 Ma. With a correlation of geochronological stratigraphy and biostratigraphy, we deduce that the Xing'anling Group, which comprises the Great Hinggan Mountains volcanic rock belt in eastern China, is predominantly of the early-middle Early Cretaceous, while the Jiande and Shimaoshan Groups and their equivalents, which form the volcanic rock belt in the southeastern coast area of China, are of the mid-late Early Cretaceous, and both the Jehol and Jiande Biotas are of the Early Cretaceous, not Late Jurassic or Late Jurassic-Early Cretaceous. Combining the characteristics of the volcanic rocks and, in a large area, hiatus in the strata of the Late Jurassic or Late Jurassic-early Early Cretaceous between the formations mentioned above and the underlying sequences, we can make the conclusion that, in the Late Jurassic-early Early Cretaceous, the eastern China region was of high relief or plateau, where widespread post-orogenic volcanic series of the Early Cretaceous obviously became younger from inland in the west to continental margin in the east. This is not the result of an oceanward accretion of the subduction belt between the Paleo-Pacific ocean plate and the Asian continent, but rather reflects the extension feature, i.e. after the closure of the Paleo-Pacific ocean, the Paleo-Pacific ancient continent collided with the Asian continent and reached the peak of orogenesis, and then the compression waned and resulted in the retreating of the post

  19. Structural control on geothermal circulation in the Cerro Tuzgle-Tocomar geothermal volcanic area (Puna plateau, Argentina)

    Giordano, Guido; Pinton, Annamaria; Cianfarra, Paola; Baez, Walter; Chiodi, Agostina; Viramonte, José; Norini, Gianluca; Groppelli, Gianluca


    The reconstruction of the stratigraphical-structural framework and the hydrogeology of geothermal areas is fundamental for understanding the relationships between cap rocks, reservoir and circulation of geothermal fluids and for planning the exploitation of the field. The Cerro Tuzgle-Tocomar geothermal volcanic area (Puna plateau, Central Andes, NW Argentina) has a high geothermal potential. It is crossed by the active NW-SE trans-Andean tectonic lineament known as the Calama-Olacapato-Toro (COT) fault system, which favours a high secondary permeability testified by the presence of numerous springs. This study presents new stratigraphic and hydrogeological data on the geothermal field, together with the analysis from remote sensed image analysis of morphostructural evidences associated with the structural framework and active tectonics. Our data suggest that the main geothermal reservoir is located within or below the Pre-Palaeozoic-Ordovician basement units, characterised by unevenly distributed secondary permeability. The reservoir is recharged by infiltration in the ridges above 4500 m a.s.l., where basement rocks are in outcrop. Below 4500 m a.s.l., the reservoir is covered by the low permeable Miocene-Quaternary units that allow a poor circulation of shallow groundwater. Geothermal fluids upwell in areas with more intense fracturing, especially where main regional structures, particularly NW-SE COT-parallel lineaments, intersect with secondary structures, such as at the Tocomar field. Away from the main tectonic features, such as at the Cerro Tuzgle field, the less developed network of faults and fractures allows only a moderate upwelling of geothermal fluids and a mixing between hot and shallow cold waters. The integration of field-based and remote-sensing analyses at the Cerro Tuzgle-Tocomar area proved to be effective in approaching the prospection of remote geothermal fields, and in defining the conceptual model for geothermal circulation.

  20. Deglaciated areas of Kilimanjaro as a source of volcanic trace elements deposited on the ice cap during the late Holocene

    Gabrielli, P.; Hardy, D. R.; Kehrwald, N.; Davis, M.; Cozzi, G.; Turetta, C.; Barbante, C.; Thompson, L. G.


    Ice fields on Kilimanjaro (5895 m a.s.l., Tanzania) are retreating and 85% of the ice cover has been lost since 1912. The degree to which this recession is exceptional during the Holocene is uncertain, as age control of the entire ice stratigraphy exists only for the very shallow and very bottom ice of the Northern Ice Field. This empirical evidence suggests that the Kilimanjaro ice cover may be a persistent Holocene feature, while a model based on maximum possible extent and a constant shrinkage rate of the summit glaciers suggests a cyclic decay time on the order of one to two centuries. Today the mass balance of these ice fields is negative and no persistent ice accumulation zones are observed over multiannual scales. The expanding deglaciated area within the Kilimanjaro caldera should act as an increasingly larger and productive source of volcanic-origin aeolian dust that is quickly deposited onto the surface of the adjacent ice fields, particularly in the seasonal absence of caldera snow cover. Variations in the local dust influx may directly influence albedo and the energy balance of these ice fields. Investigating the characteristics of insoluble material entrapped in the ice remnants of Kilimanjaro can thus provide insights into the extent of ice and/or continuity of the summit snow cover through time. Here we report the trace element composition linked to the insoluble particles entrapped in Holocene Kilimanjaro ice in the context of the current understanding of the past ice accumulation processes (including solid precipitations and ablation) contributing to build the horizontal caldera ice fields. For this purpose we analysed an ice core drilled to bedrock from the Northern Ice Field thought to span the late Holocene (2200 BC-1950 AD). The ultra low trace element concentrations recorded in this Kilimanjaro core are consistent with a generally low volcanic dust source availability (i.e. limited exposure of the deglaciated area in the caldera) and fairly

  1. Geochemistry and geochronology of granitoids in the Kibi-Asamankese area of the Kibi-Winneba volcanic belt, southern Ghana

    Anum, Solomon; Sakyi, Patrick Asamoah; Su, Ben-Xun; Nude, Prosper M.; Nyame, Frank; Asiedu, Daniel; Kwayisi, Daniel


    In Ghana the West African Craton is represented by Birimian and Tarkwaian rocks with extensive granitoid bodies. Granitoids from Asamankese area of the Kibi-Winneba volcanic belt, southern Ghana were analysed for major and trace element contents and found to be characterised by highly-fractionated REE, enrichments, in LILE, and depletion in Nb, Ta and Sr. The LILE enrichment relative to strong Nb-Ta depression, indicates that these granitoids were emplaced in an active margin. Based on field relations, geochemical composition and geochronological data, the granitoids from the Kibi-Asamankese area can be divided into three types, namely; the Eburnean biotite granodiorite (2133-2127 Ma) and hornblende granodiorite (2147 Ma), and the Pre-Eburnean gneissic biotite granite (2193 Ma). The geochemical data of the studied rocks plot in the tholeiitic field, whereas on the A/CNK-A/NK diagram, they generally fall within the metaluminous field, with A/CNK values between 0.69 and 0.88. U-Pb dating of zircons in the granitoids yielded ages ranging from 2193 to 2127 Ma, which are among the oldest ages obtained from the granitoid plutons in Ghana. Such high-precision geochronological data indicate that magmatism occurred over a time-span of about 70 Ma. This provides further evidence that the period 2.1-2.2 Ga was one of the important stages of Birimian magmatism that led to the generation of the granitoids. From the above-mentioned ages, it is possible to link the geological activities to crustal processes and establish the cyclic geotectonic evolution in the West African Craton over time as part of an arc-back-arc basin system.

  2. Geology and geochemistry of palaeoproterozoic low-grade metabasic volcanic rocks from Salumber area, Aravalli Supergroup, NW India

    L S Shekhawat; M K Pandit; D W Joshi


    The Palaeoproterozoic Aravalli Supergroup in Salumber region includes a basal unit of metabasic volcanic rocks (Salumber volcanic rocks) overlain by a volcaniclastic/conglomerate one. Although these volcanic rocks have been metamorphosed to green-schist facies, some primary volcanic features are still preserved. This metabasic volcanic sequence can be further differentiated on the basis of textural variations, and the mineral assemblages are: (a) oligoclase + actinolite + chlorite + epidote; and (b) oligoclase + hornblende+ chlorite + biotite + Fe-Ti oxides. The SiO2 content ranges from ∼47.7 to 55.8% and MgO from ∼4.2 to 12.8%. Geochemical characteristics allow their subdivision into high Mg and Fe tholeiites. Inverse relationship of MgO with silica, alkalis and Zr is generally consistent with fractionation mechanism, also suggested by a change in colour of the rocks from dark greenish to light greenish towards the upper parts of the sequence. These metabasic volcanic rocks are enriched in incompatible trace elements and LREE (La = 30 − 40 × chondrite, Lu = 2 − 5 × chondrite), and demonstrate affinity mainly with MORB and within plate settings in geochemical tectonic discrimination schemes. The geochemical characteristics suggest a complex evolutionary history envisaging derivation of the melt from an enriched heterogeneous lithospheric source.

  3. Elastic stress interaction between faulting and volcanism in the Olacapato-San Antonio de Los Cobres area (Puna plateau, Argentina)

    Bonali, F. L.; Corazzato, C.; Tibaldi, A.


    We describe the relationships between Plio-Quaternary tectonics, palaeoseismicity and volcanism along the NW-trending Calama-Olacapato-El Toro (COT) lineament that crosses the Andean chain and the Puna Plateau and continues within the eastern Cordillera at about 24° S. We studied in detail the area from the Chile-Argentina border to a few km east of the San Antonio del Los Cobres village. Satellite and field data revealed the presence of seven Quaternary NW-striking normal left-lateral fault segments in the southeastern part of the studied area and of a Plio-Quaternary N-S-striking graben structure in the northwestern part. The NW-striking Chorrillos fault (CF) segment shows the youngest motions, of late Pleistocene age, being marked by several fault scarps, sag ponds and offset Quaternary deposits and landforms. Offset lavas of 0.78 ± 0.1 Ma to 0.2 ± 0.08 Ma indicate fault kinematics characterised by a pitch angle of 20° to 27° SE, a total net displacement of 31 to 63.8 m, and a slip-rate of 0.16 to 0.08 mm/yr. This fault segment is 32 km long and terminates to the northwest near a set of ESE-dipping thrust faults affecting Tertiary strata, while to the southeast it terminates 10 km further from San Antonio. In the westernmost part of the examined area, in Chile at altitudes > 4000 m, recent N-S-striking normal fault scarps depict the 5-km-wide and 10-km-long graben structure. Locally, fault pitches indicate left-lateral normal kinematics. These faults affect deposits up to ignimbrites of Plio-Quaternary age. Scarp heights are from a few metres to 24 m. Despite that this area is located along the trace of the COT strike-slip fault system, which is reported as a continuous structure from Chile to Argentina in the literature, no evidence of NW-striking Plio-Quaternary strike-slip structures is present here. A series of numerical models were also developed in an elastic half-space with uniform isotropic elastic properties using the Coulomb 3.1 code. We studied

  4. Dating and source determination of volcanic rocks from Khunik area (South of Birjand, South Khorasan using Rb-Sr and Sm-Nd isotopes

    Somayeh Samiee


    Full Text Available The Khunik area is located in the south of Birjand, Khorasan province, in the eastern margin of Lut block. Tertiary volcanic rocks have andesite to trachy-andesite composition. Dating analyzing by Rb-Sr method on plagioclase and hornblende as well as whole-rock isochron method was performed on pyroxene-hornblende andesite rock unit. On this basis the emplacement age is Upper Paleocene (58±11 Ma. These rocks have initial 87Sr/86Sr and εNd 0.7046-0.7049 and 2.16-3.12, respectively. According to isotopic data, volcanic rocks originated from depleted mantle and have the least crust contamination while it was fractionated. Geochemically, Khunik volcanic rocks have features typical of calk-alkaline to shoshonite and are metaluminous. Enrichment in LILEs and typical negative anomalies of Nb and Ti are evidences that the volcanic rocks formed in a subduction zone and active continental margin. Modeling suggests that these rocks were derived dominantly from 1–5% partial melting of a mainly spinel garnet lherzolite mantle source that is metasomatized by slab-derived fluid.

  5. Planning the improvement of a seismic network for monitoring active volcanic areas: the experience on Mt. Etna

    D'Alessandro, A.; Scarfì, L.; Scaltrito, A.; Di Prima, S.; Rapisarda, S.


    Seismology and geodesy are generally seen as the most reliable diagnostic tools for monitoring highly active or erupting volcanoes, like Mt. Etna. From the early 1980's, seismic activity was monitored at Mt. Etna by a permanent seismic network, progressively improved in the following years. This network has been considerably enhanced since 2005 by 24-bit digital stations equipped with broad-band (40 s) sensors. Today, thanks to a configuration of 33 broad-band and 12 short-period stations, we have a good coverage of the volcanic area as well as a high quality of the collected data. In the framework of the VULCAMED project a workgroup of Istituto Nazionale di Geofisica e Vulcanologia has taken on the task of developing the seismic monitoring system, through the installation of other seismic stations. The choice of optimal sites must be clearly made through a careful analysis of the geometry of the existing seismic network. In this paper, we applied the Seismic Network Evaluation through Simulation in order to evaluate the performance of the Etna Seismic Network before and after the addition of the stations in the candidate sites. The main advantage of the adopted method is that we can evaluate the improvement of the network before the actual installation of the stations. Our analysis has permitted to identify some critical issues of the current permanent seismic network related to the lack of stations in the southern sector of the volcano, which is nevertheless affected by a number of seismogenic structures. We have showed that the addition of stations at the candidate sites would greatly extend the coverage of the network to the south by significantly reducing the errors in the hypocenter parameters estimation.

  6. Hydrothermal systems in two areas of the Jemez volcanic field: Sulphur Springs and the Cochiti mining district

    WoldeGabriel, G.


    K/Ar dates and oxygen isotope data were obtained on 13 clay separates (<2 of thermally altered mafic and silicic rocks from the Cochiti mining district (SE Jemez Mountains) and Continental Scientific Drilling Project (CSDP) core hole VC-2A (Sulphur Springs, Valles caldera). Illite with K/sub 2/O contents of 6.68%--10.04% is the dominant clay in the silicic rocks, whereas interstratified illite/smectites containing 1.4%--5.74% K/sub 2/O constitute the altered andesites. Two hydrothermal alteration events are recognized at the Cochiti area (8.07 m.y., n = 1, and 6.5--5.6 m.y., n = 6). The older event correlates with the waning stages of Paliza Canyon Formation andesite volcanism (greater than or equal to13 to less than or equal to8.5 m.y.), whereas the younger event correlates with intrusions and gold- and silver-bearing quartz veins associated with the Bearhead Rhyolite (7.54--5.8 m.y.). The majority of K/Ar dates in the hydrothermally altered, caldera-fill rocks of core hole VC-2A (0.83--0.66 m.y., n = 4) indicate that hydrothermal alteration developed contemporaneously with resurgence and ring fracture Valles Rhyolite domes (0.89--0.54 m.y.). One date of 0 +- 0.10 m.y. in acid-altered landslide debris of postcaldera tuffs from the upper 13 m of the core hole probably correlates with Holocene hydrothermal activity possibly associated with the final phases of the Valles Rhyolite (0.13 m.y.).

  7. Elastic stress interaction between faulting and volcanism in the Olacapato-San Antonio de Los Cobres area (NW Argentina)

    Bonali, F. L.; Tibaldi, A.; Corazzato, C.; Lanza, F.; Cavallo, A.; Nardin, A.


    The aim of this work is to describe the relationships between Plio-Quaternary tectonics, palaeoseismicity and volcanism along the NW-trending Calama-Olacapato-El Toro (COT) lineament that crosses the Andean chain and the Puna Plateau and continues within the eastern Cordillera at about 24° S. Field and satellite data have been collected from the Chile-Argentina border to a few km east of the San Antonio del Los Cobres village. These data revealed the presence of seven Quaternary NW-striking normal left-lateral fault segments in the southeastern part of the studied area and of a Plio-Quaternary N-S-striking graben structure in the northwestern part. The NW-striking Chorrillos fault (CF) segment shows the youngest motions, of late Pleistocene age, being marked by several fault scarps, sag-ponds and offset Quaternary deposits and landforms. Offset lavas of 0.78±0.1 Ma to 0.2±0.08 Ma indicate fault kinematics characterized by a pitch angle of 20° to 27° SE, a total net displacement that ranges from 31 to 63.8 m, and a slip-rate of 0.16 to 0.08 mm/yr. This fault segment is 32 km long and terminates to the northwest near a set of ESE-dipping thrust faults affecting Tertiary strata, while to the southeast it terminates 10 km further from San Antonio. In the westernmost part of the examined area, in Chile at altitudes of 4000 m, recent N-S-striking normal fault scarps depict the 5-km-wide and 10-km-long graben structure. Locally, fault pitches indicate left-lateral normal kinematics. These faults affect deposits up to ignimbrites of Plio-Quaternary age. Scarp heights are from a few metres to 24 m. Despite this area is located along the trace of the COT strike-slip fault system, which is reported as a continuous structure from Chile to Argentina in the literature, no evidence of NW-striking Plio-Quaternary strike-slip structures is present here. A series of numerical models were developed in an elastic half-space with uniform isotropic elastic properties using the

  8. Geochronology and geochemistry of Eocene-aged volcanic rocks around the Bafra (Samsun, N Turkey) area: Constraints for the interaction of lithospheric mantle and crustal melts

    Temizel, İrfan; Arslan, Mehmet; Yücel, Cem; Abdioğlu, Emel; Ruffet, Gilles


    40Ar-39Ar age, whole-rock chemical, and Sr-Nd isotope data are presented for the post-collisional, Eocene (51.3-44.1 Ma)-aged volcanic rocks from the Bafra (Samsun) area in the western part of the Eastern Pontides (N Turkey) aiming to unravel their sources and evolutionary history. The studied Eocene volcanic rocks can be divided into two groups: analcime-bearing (tephritic lava flows and dykes) and analcime-free (basaltic to trachytic lava flows and basaltic dykes). The analcime-bearing volcanic rocks have a fine-grained porphyritic texture with clinopyroxene phenocrysts, whereas analcime-free volcanic rocks show a variety of textures including hyalo-microlitic microgranular porphyritic, intersertal, trachytic, fluidal, and glomeroporphyritic. The volcanic rocks also show evidence of mineral-melt disequilibrium textures such as sieved, rounded, and corroded plagioclases, partially melted and dissolved clinopyroxenes and poikilitic texture. Petrochemically, the parental magmas of the volcanic rocks evolved from alkaline to calc-alkaline lava suites and include high-K and shoshonitic compositions. They display enrichments in light rare earth and large ion lithophile elements such as Sr, K, and Rb, as well as depletions in high field strength elements such as Nb, Ta, Zr, and Ti, resembling subduction-related magmas. The analcime-bearing and -free volcanic rocks share similar incompatible element ratios and chondrite-normalised rare rearth element patterns, indicating that they originated from similar sources. They also have relatively low to moderate initial 87Sr/86Sr (0.7042-0.7051), high positive εNd(t) values (+ 0.20 to + 3.32), and depleted mantle Nd model ages (TDM1 = 0.63-0.93 Ga, TDM2 = 0.58-0.84 Ga). The bulk-rock chemical and Sr-Nd isotope features as well as the high Rb/Y and Th/Zr, but low Nb/Zr and Nb/Y ratios, indicate that the volcanic rocks were derived from a lithospheric mantle source that had been metasomatised by slab-derived fluids. Trace element

  9. Volcanic Catastrophes

    Eichelberger, J. C.


    volcanism on humankind in the North Pacific, where Holocene time saw many caldera-forming eruptions in an area of comparatively intense human activity.

  10. Catastrophic volcanism

    Lipman, Peter W.


    Since primitive times, catastrophes due to volcanic activity have been vivid in the mind of man, who knew that his activities in many parts of the world were threatened by lava flows, mudflows, and ash falls. Within the present century, increasingly complex interactions between volcanism and the environment, on scales not previously experienced historically, have been detected or suspected from geologic observations. These include enormous hot pyroclastic flows associated with collapse at source calderas and fed by eruption columns that reached the stratosphere, relations between huge flood basalt eruptions at hotspots and the rifting of continents, devastating laterally-directed volcanic blasts and pyroclastic surges, great volcanic-generated tsunamis, climate modification from volcanic release of ash and sulfur aerosols into the upper atmosphere, modification of ocean circulation by volcanic constructs and attendent climatic implications, global pulsations in intensity of volcanic activity, and perhaps triggering of some intense terrestrial volcanism by planetary impacts. Complex feedback between volcanic activity and additional seemingly unrelated terrestrial processes likely remains unrecognized. Only recently has it become possible to begin to evaluate the degree to which such large-scale volcanic processes may have been important in triggering or modulating the tempo of faunal extinctions and other evolutionary events. In this overview, such processes are examined from the viewpoint of a field volcanologist, rather than as a previous participant in controversies concerning the interrelations between extinctions, impacts, and volcanism.

  11. Development of a low cost and low power consumption system for monitoring CO_{2} soil concentration in volcanic areas.

    Awadallah Estévez, Shadia; Moure-García, David; Torres-González, Pedro; Acosta Sánchez, Leopoldo; Domínguez Cerdeña, Itahiza


    Volatiles dissolved in magma are released as gases when pressure or stress conditions change. H2O, CO2, SO2 and H2S are the most abundant gases involved in volcanic processes. Emission rates are related to changes in the volcanic activity. Therefore, in order to predict possible eruptive events, periodic measurements of CO2 concentrations from the soil should be carried out. In the last years, CO2 monitoring has been widespread for many reasons. A direct relationship between changes in volcanic activity and variations in concentration, diffuse flux and isotope ratios of this gas, have been observed prior to some eruptions or unrest processes. All these factors have pointed out the fact that CO2 emission data are crucial in volcanic monitoring programs. In addition, relevant instrumentation development has also taken place: improved accuracy, cost reduction and portability. Considering this, we propose a low cost and a low power consumption system for measuring CO2 concentration in the soil based on Arduino. Through a perforated pick-axe buried at a certain depth, gas samples are periodically taken with the aid of a piston. These samples are injected through a pneumatic circuit in the spectrometer, which measures the CO2 concentration. Simultaneously, the system records the following meteorological parameters: atmospheric pressure, precipitation, relative humidity and air and soil temperature. These parameters are used to correct their possible influence in the CO2 soil concentration. Data are locally stored (SD card) and transmitted via GPRS or WIFI to a data analysis center.

  12. Magma injection beneath the urban area of Naples: a new mechanism for the 2012–2013 volcanic unrest at Campi Flegrei caldera

    D’Auria, Luca; Pepe, Susi; Castaldo, Raffaele; Giudicepietro, Flora; Macedonio, Giovanni; Ricciolino, Patrizia; Tizzani, Pietro; Casu, Francesco; Lanari, Riccardo; Manzo, Mariarosaria; Martini, Marcello; Sansosti, Eugenio; Zinno, Ivana


    We found the first evidence, in the last 30 years, of a renewed magmatic activity at Campi Flegrei caldera from January 2012 to June 2013. The ground deformation, observed through satellite interferometry and GPS measurements, have been interpreted as the effect of the intrusion at shallow depth (3090 ± 138 m) of 0.0042 ± 0.0002 km3 of magma within a sill. This interrupts about 28 years of dominant hydrothermal activity and occurs in the context of an unrest phase which began in 2005 and within a more general ground uplift that goes on since 1950. This discovery has implications on the evaluation of the volcanic risk and in the volcanic surveillance of this densely populated area. PMID:26279090

  13. Controls on volcanism at intraplate basaltic volcanic fields

    van den Hove, Jackson C.; Van Otterloo, Jozua; Betts, Peter G.; Ailleres, Laurent; Cas, Ray A. F.


    A broad range of controlling mechanisms is described for intraplate basaltic volcanic fields (IBVFs) in the literature. These correspond with those relating to shallow tectonic processes and to deep mantle plumes. Accurate measurement of the physical parameters of intraplate volcanism is fundamental to gain an understanding of the controlling factors that influence the scale and location of a specific IBVF. Detailed volume and geochronology data are required for this; however, these are not available for many IBVFs. In this study the primary controls on magma genesis and transportation are established for the Pliocene-Recent Newer Volcanics Province (NVP) of south-eastern Australia as a case-study for one of such IBVF. The NVP is a large and spatio-temporally complex IBVF that has been described as either being related to a deep mantle plume, or upper mantle and crustal processes. We use innovative high resolution aeromagnetic and 3D modelling analysis, constrained by well-log data, to calculate its dimensions, volume and long-term eruptive flux. Our estimates suggest volcanic deposits cover an area of 23,100 ± 530 km2 and have a preserved dense rock equivalent of erupted volcanics of least 680 km3, and may have been as large as 900 km3. The long-term mean eruptive flux of the NVP is estimated between 0.15 and 0.20 km3/ka, which is relatively high compared with other IBVFs. Our comparison with other IBVFs shows eruptive fluxes vary up to two orders of magnitude within individual fields. Most examples where a range of eruptive flux is available for an IBVF show a correlation between eruptive flux and the rate of local tectonic processes, suggesting tectonic control. Limited age dating of the NVP has been used to suggest there were pulses in its eruptive flux, which are not resolvable using current data. These changes in eruptive flux are not directly relatable to the rate of any interpreted tectonic driver such as edge-driven convection. However, the NVP and other

  14. Assessment of volcanic hazards, vulnerability, risk and uncertainty (Invited)

    Sparks, R. S.


    many sources of uncertainty in forecasting the areas that volcanic activity will effect and the severity of the effects. Uncertainties arise from: natural variability, inadequate data, biased data, incomplete data, lack of understanding of the processes, limitations to predictive models, ambiguity, and unknown unknowns. The description of volcanic hazards is thus necessarily probabilistic and requires assessment of the attendant uncertainties. Several issues arise from the probabilistic nature of volcanic hazards and the intrinsic uncertainties. Although zonation maps require well-defined boundaries for administrative pragmatism, such boundaries cannot divide areas that are completely safe from those that are unsafe. Levels of danger or safety need to be defined to decide on and justify boundaries through the concepts of vulnerability and risk. More data, better observations, improved models may reduce uncertainties, but can increase uncertainties and may lead to re-appraisal of zone boundaries. Probabilities inferred by statistical techniques are hard to communicate. Expert elicitation is an emerging methodology for risk assessment and uncertainty evaluation. The method has been applied at one major volcanic crisis (Soufrière Hills Volcano, Montserrat), and is being applied in planning for volcanic crises at Vesuvius.

  15. Slope instability induced by volcano-tectonics as an additional source of hazard in active volcanic areas: the case of Ischia island (Italy)

    Della Seta, Marta; Marotta, Enrica; Orsi, Giovanni; de Vita, Sandro; Sansivero, Fabio; Fredi, Paola


    Ischia is an active volcanic island in the Gulf of Naples whose history has been dominated by a caldera-forming eruption (ca. 55 ka) and resurgence phenomena that have affected the caldera floor and generated a net uplift of about 900 m since 33 ka. The results of new geomorphological, stratigraphical and textural investigations of the products of gravitational movements triggered by volcano-tectonic events have been combined with the information arising from a reinterpretation of historical chronicles on natural phenomena such as earthquakes, ground deformation, gravitational movements and volcanic eruptions. The combined interpretation of all these data shows that gravitational movements, coeval to volcanic activity and uplift events related to the long-lasting resurgence, have affected the highly fractured marginal portions of the most uplifted Mt. Epomeo blocks. Such movements, mostly occurring since 3 ka, include debris avalanches; large debris flows (lahars); smaller mass movements (rock falls, slumps, debris and rock slides, and small debris flows); and deep-seated gravitational slope deformation. The occurrence of submarine deposits linked with subaerial deposits of the most voluminous mass movements clearly shows that the debris avalanches impacted on the sea. The obtained results corroborate the hypothesis that the behaviour of the Ischia volcano is based on an intimate interplay among magmatism, resurgence dynamics, fault generation, seismicity, slope oversteepening and instability, and eruptions. They also highlight that volcano-tectonically triggered mass movements are a potentially hazardous phenomena that have to be taken into account in any attempt to assess volcanic and related hazards at Ischia. Furthermore, the largest mass movements could also flow into the sea, generating tsunami waves that could impact on the island's coast as well as on the neighbouring and densely inhabited coast of the Neapolitan area.

  16. Four areas of engagement requiring strengthening in modern proteomics today.

    Fehniger, Thomas E; Boja, Emily S; Rodriguez, Henry; Baker, Mark S; Marko-Varga, György


    The global human proteomics community in 2014 is fully engaged in projects that aim to create a better understanding of human biology and its complexities and to provide products from this new knowledge that will in some way benefit humanity. Human proteomics, like any other scientific enterprise, needs to identify areas of direction and development, both for the near future in completing current research projects and into the long-term for the engagement with even more complex challenges. In this Editorial we highlight and discuss four important areas that we collectively believe require attention and demand a collective response going forward. These four areas are: (1) Provide high-quality standardized, sensitive, specific, quantitative, and readily accessible protein, peptide, or other biomarkers of health, disease, response to therapy into the approval processes of regulatory agencies (e.g., U.S. Food and Drug Administration; FDA), and obtaining approval from the relevant agencies for their use in a clinical or other testing settings. (2) Implement standard processes for collecting, processing, and storing human clinical samples in biorepositories and enforcement of measures to ensure subject integrity including informed consent for the downstream use of samples and in registrations of subject identities within study databases. (3) Test and validate mass spectrometry technology platforms that hold much promise for creating opportunities for obtaining new important knowledge at levels of detection previously not achievable. (4) Organize clinical discovery operations and activities in an intuitive manner to meet the challenges of increased interests in the science we provide and diminishing levels of centrally financed resource and infrastructure support.

  17. Gas Geochemistry of Volcanic and Geothermal Areas in the Kenya Rift: Implications for the Role of Fluids in Continental Rifting

    Lee, H.; Fischer, T. P.; Ranka, L. S.; Onguso, B.; Kanda, I.; Opiyo-Akech, N.; Sharp, Z. D.; Hilton, D. R.; Kattenhorn, S. A.; Muirhead, J.


    The East African Rift (EAR) is an active continental rift and ideal to investigate the processes of rift initiation and the breaking apart of continental lithosphere. Mantle and crust-derived fluids may play a pivotal role in both magmatism and faulting in the EAR. For instance, large quantities of mantle-derived volatiles are emitted at Oldoinyo Lengai volcano [1, 2]. Throughout the EAR, CO2-dominated volatile fluxes are prevalent [3, 4] and often associated with faults (i.e. Rungwe area, Tanzania, [5, 6]). The purpose of this study is to examine the relationship between volcanism, faulting and the volatile compositions, focusing on the central and southern Kenyan and northern Tanzanian section of the EAR. We report our analysis results for samples obtained during a 2013 field season in Kenya. Gases were sampled at fumaroles and geothermal plants in caldera volcanoes (T=83.1-120.2°C) and springs (T=40-79.6°C and pH 8.5-10) located near volcanoes, intra-rift faults, and a transverse fault (the Kordjya fault, a key fluid source in the Magadi rift) by 4N-NaOH solution-filled and empty Giggenbach bottles. Headspace gases were analyzed by a Gas Chromatograph and a Quadrupole Mass Spectrometer at the University of New Mexico. Both N2/Ar and N2/He ratios of all gases (35.38-205.31 and 142.92-564,272, respectively) range between air saturated water (ASW, 40 and ≥150,000) and MORB (100-200 and 40-50). In addition, an N2-Ar-He ternary diagram supports that the gases are produced by two component (mantle and air) mixing. Gases in the empty bottles from volcanoes and springs have N2 (90.88-895.99 mmom/mol), CO2 (2.47-681.21 mmom/mol), CH4 (0-214.78 mmom/mol), O2 (4.47-131.12 mmom/mol), H2 (0-35.78 mmom/mol), Ar (0.15-10.65 mmom/mol), He (0-2.21 mmom/mol), and CO (0-0.08 mmom/mol). Although some of the samples show an atmospheric component, CO2 is a major component in most samples, indicating both volcanoes and springs are emitting CO2. Gases from volcanoes are enriched in

  18. Sentinel-1 automatic processing chain for volcanic and seismic areas monitoring within the Geohazards Exploitation Platform (GEP)

    De Luca, Claudio; Zinno, Ivana; Manunta, Michele; Lanari, Riccardo; Casu, Francesco


    The microwave remote sensing scenario is rapidly evolving through development of new sensor technology for Earth Observation (EO). In particular, Sentinel-1A (S1A) is the first of a sensors' constellation designed to provide a satellite data stream for the Copernicus European program. Sentinel-1A has been specifically designed to provide, over land, Differential Interferometric Synthetic Aperture Radar (DInSAR) products to analyze and investigate Earth's surface displacements. S1A peculiarities include wide ground coverage (250 km of swath), C-band operational frequency and short revisit time (that will reduce from 12 to 6 days when the twin system Sentinel-1B will be placed in orbit during 2016). Such characteristics, together with the global coverage acquisition policy, make the Sentinel-1 constellation to be extremely suitable for volcanic and seismic areas studying and monitoring worldwide, thus allowing the generation of both ground displacement information with increasing rapidity and new geological understanding. The main acquisition mode over land is the so called Interferometric Wide Swath (IWS) that is based on the Terrain Observation by Progressive Scans (TOPS) technique and that guarantees the mentioned S1A large coverage characteristics at expense of a not trivial interferometric processing. Moreover, the satellite spatial coverage and the reduced revisit time will lead to an exponential increase of the data archives that, after the launch of Sentine-1B, will reach about 3TB per day. Therefore, the EO scientific community needs from the one hand automated and effective DInSAR tools able to address the S1A processing complexity, and from the other hand the computing and storage capacities to face out the expected large amount of data. Then, it is becoming more crucial to move processors and tools close to the satellite archives, being not efficient anymore the approach of downloading and processing data with in-house computing facilities. To address

  19. Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona

    Tanaka, K.L.; Skinner, J.A.; Crumpler, L.S.; Dohm, J.M.


    understand that surficial materials (such as alluvium and volcanic ash deposits) are likely to be under-mapped yet are important because they obscure underlying units and contacts; (4) where possible, mapping multiple contact and structure types based on their varying certainty and exposure that reflect the perceived accuracy of the linework; (5) reviewing the regional context and searching for evidence of geologic activity that may have affected the map area yet for which evidence within the map area may be absent; and (6) for multi-authored maps, collectively analyzing the mapping relations, approaches, and methods throughout the duration of the mapping project with the objective of achieving a solid, harmonious product.

  20. Paleomagnetic secular variation study of Ar-Ar dated lavas flows from Tacambaro area (Central Mexico): Possible evidence of Intra-Jaramillo geomagnetic excursion in volcanic rocks

    Peña, Rafael Maciel; Goguitchaichvili, Avto; Guilbaud, Marie-Noëlle; Martínez, Vicente Carlos Ruiz; Rathert, Manuel Calvo; Siebe, Claus; Reyes, Bertha Aguilar; Morales, Juan


    More than 350 oriented paleomagnetic cores were obtained for rock-magnetic and paleomagnetic analysis from radiometrically dated (40Ar-39Ar) magmatic rocks occurring in the southern segment (Jorullo and Tacámbaro areas) of the Michoacán-Guanajuato Volcanic Field in the Trans-Mexican Volcanic Belt. Most of the lavas (37) stem from monogenetic volcanoes dated at less than 4 Ma. Two additional sites were sampled from the plutonic basement dated at 33-30 Ma. Primary remanences carried by low-Ti titanomagnetites allowed to determining 34 reliable site-mean directions of mostly normal (27) but also reversed (7) polarities. The mean directions of these two populations are antipodal, and suggest neither major vertical-axis rotations with respect to the North America craton nor tilting in the region for the last 4 Ma (rotation and flattening of the inclination parameters being less than -5.9 ± 3.8 and 0.1 ± 3.9, respectively). The corresponding paleomagnetic pole obtained for Pliocene-Pleistocene times is PLAT = 83.4°, PLON = 2.4° (N = 32, A95 = 2.7°). Virtual geomagnetic poles also contribute to the time averaged field global database and to the paleosecular variation (PSV) investigations at low latitudes from lavas for the last 5 Ma, showing a geomagnetic dispersion value that is in agreement with available PSV models. When comparing the magnetic polarities and corresponding radiometric ages of the studied sites with the Cenozoic geomagnetic polarity time scale (GPTS), a good correlation is observable. This finding underscores the suitability of data obtained on lavas in Central Mexico for contributing to the GPTS. Furthermore, the detection of short-lived geomagnetic features seems possible, since the possible evidence of Intra-Jaramillo geomagnetic excursion could be documented for the first time in these volcanic rocks.

  1. Global positioning system survey data for active seismic and volcanic areas of eastern Sicily, 1994 to 2013

    Bonforte, Alessandro; Fagone, Sonia; Giardina, Carmelo; Genovese, Simone; Aiesi, Gianpiero; Calvagna, Francesco; Cantarero, Massimo; Consoli, Orazio; Consoli, Salvatore; Guglielmino, Francesco; Puglisi, Biagio; Puglisi, Giuseppe; Saraceno, Benedetto


    This work presents and describes a 20-year long database of GPS data collected by geodetic surveys over the seismically and volcanically active eastern Sicily, for a total of more than 6300 measurements. Raw data were initially collected from the various archives at the Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania—Osservatorio Etneo and organized in a single repository. Here, quality and completeness checks were performed, while all necessary supplementary information were searched, collected, validated and organized together with the relevant data. Once all data and information collections were completed, raw binary data were converted into the universal ASCII RINEX format; all data are provided in this format with the necessary information for precise processing. In order to make the data archive readily consultable, we developed software allowing the user to easily search and obtain the needed data by simple alphanumeric and geographic queries.

  2. Global positioning system survey data for active seismic and volcanic areas of eastern Sicily, 1994 to 2013.

    Bonforte, Alessandro; Fagone, Sonia; Giardina, Carmelo; Genovese, Simone; Aiesi, Gianpiero; Calvagna, Francesco; Cantarero, Massimo; Consoli, Orazio; Consoli, Salvatore; Guglielmino, Francesco; Puglisi, Biagio; Puglisi, Giuseppe; Saraceno, Benedetto


    This work presents and describes a 20-year long database of GPS data collected by geodetic surveys over the seismically and volcanically active eastern Sicily, for a total of more than 6300 measurements. Raw data were initially collected from the various archives at the Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania-Osservatorio Etneo and organized in a single repository. Here, quality and completeness checks were performed, while all necessary supplementary information were searched, collected, validated and organized together with the relevant data. Once all data and information collections were completed, raw binary data were converted into the universal ASCII RINEX format; all data are provided in this format with the necessary information for precise processing. In order to make the data archive readily consultable, we developed software allowing the user to easily search and obtain the needed data by simple alphanumeric and geographic queries.

  3. Data requirements and data sources for biodiversity priority area selection

    P H Williams; C R Margules; D W Hilbert


    The data needed to prioritize areas for biodiversity protection are records of biodiversity features – species, species assemblages, environmental classes – for each candidate area. Prioritizing areas means comparing candidate areas, so the data used to make such comparisons should be comparable in quality and quantity. Potential sources of suitable data include museums, herbariums and natural resource management agencies. Issues of data precision, accuracy and sampling bias in data sets from such sources are discussed and methods for treating data to minimize bias are reviewed.

  4. High-resolution remote sensing data to monitor active volcanic areas: an application to the 2011-2015 eruptive activity of Mount Etna (Italy) (Conference Presentation)

    Marsella, Maria


    In volcanic areas, where it could be difficult to gain access to the most critical zones for carrying out direct surveys, remote sensing proved to have remarkable potentialities to follow the evolution of lava flow, as well as to detect slope instability processes induced by volcanic activity. By exploiting SAR and optical data a methodology for observing and quantifying eruptive processes was developed. The approach integrates HR optical images and SAR interferometric products and can optimize the observational capability of standard surveillance activities based on in-situ video camera network. A dedicated tool for mapping the evolution of the lava field, using both ground-based and satellite data, was developed and tested to map lava flows during the 2011-2015 eruptive activities. Ground based data were collected using the permanent ground NEtwork of Thermal and VIsible Sensors located on Mt. Etna (Etna_NETVIS) and allowed to downscale the information derived from satellite data and to integrate the satellite datasets in case of incomplete coverage or missing acquisitions. This work was developed in the framework of the EU-FP7 project "MED-SUV" (MEDiterranean SUpersite Volcanoes).

  5. Analysis of Tactical Automation Requirements for the Maneuver Functional Area.



  6. Infrastructure Requirements in the Area of Bankruptcy Law

    Clas Wihlborg; Shubhashis Gangopadhyay


    Infrastructure requirements have long played an important role in the development debate. Until recently these requirements referred to the need for improvements in roads, railways, electricity supply, telecommunications and the like. Lack of such infrastructure was seen as an important cause of a country's relative poverty. Investments in physical infrastructure seem not to have had the desired growth effects in developing countries, however. The search for the root cause of economic develop...

  7. Deconvolving the process-origin of sediments on volcanic mountains and implications for paleoclimatic reconstruction: Mt Ruapehu area, New Zealand

    Brook, Martin; Winkler, Stefan


    Glaciation on the central North Island of New Zealand is limited to the volcanoes of Tongariro National Park, including Mt Ruapehu, the largest and most active andesitic stratovolcano on the North Island. At 2797 m asl, Mt Ruapehu represents the only peak in the North Island to currently intercept the permanent snowline, with small cirque glaciers descending to an altitude of ~2300 m. During the last glacial maximum (LGM), small ice-caps existed on Mt Ruapehu and the Tongariro Massif (15 km to the NNE of Ruapehu), with a series of small (cirque glaciers, consists mainly of incorporated fluvial material. Following deposition, reworking is mainly by proglacial streams, debris flows and lahars. Within the vicinity of glaciers, the dominant facies appear to be: (i) bouldery gravel with angular clasts on steep slopes surrounding glaciers, (ii) silty-sandy boulder gravel, with mainly subangular clasts, forming lateral moraines, (iii) boulder/cobble gravel with mainly subrounded clasts and associated laminated sediments representing fluvially-reworked material; and (iv) debris-avalanche deposits including fragmental rock clasts with an unsorted inter-clast matrix. As some of these deposits appear to include unambiguous indicators of glacial transport, interpretation of unconsolidated debris ridges on volcanic mountains should not necessarily exclude the contribution of glacial processes.

  8. Modeling volcanic ash dispersal

    CERN. Geneva


    The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

  9. 7 CFR 25.103 - Area size and boundary requirements


    ... within no more than three contiguous States; (4) May not include any portion of a central business district (as such term is used for purposes of the most recent Census of Retail Trade) unless the poverty... miles shall be reduced to a 1,000 square mile area with a continuous boundary, if necessary,...

  10. A quantitative model for volcanic hazard assessment

    W. Marzocchi; Sandri, L.; Furlan, C


    Volcanic hazard assessment is a basic ingredient for risk-based decision-making in land-use planning and emergency management. Volcanic hazard is defined as the probability of any particular area being affected by a destructive volcanic event within a given period of time (Fournier d’Albe 1979). The probabilistic nature of such an important issue derives from the fact that volcanic activity is a complex process, characterized by several and usually unknown degrees o...

  11. Late Pleistocene to Holocene soil development and environments in the Long Gang Volcanic Field area, Jilin Province, NE China

    Sauer, Daniela; Zhang, Xinrong; Knöbel, Jette; Maerker, Lutz


    Late Pleistocene to Holocene shifts of climate and vegetation in the Long Gang Volcanic Field in NE China have been reconstructed, e. g. by Steblich et al. (2009), based on Maar lake sediment cores. In this study, we investigated soil development during the Late Pleistocene and Holocene and linked it to the climate and vegetation reported in the literature. Three pedons were described and analyzed on a crater wall surrounding a maar. The lower part of the slope is covered by basic pyroclastics that are obviously younger than the maar itself. Pedon 1 is located on the upper slope, where the younger pyroclastics are not present; thus it developed over the entire Holocene and part of the Late Pleistocene. Pedon 2 is on the toe slope and developed from the young basic pyroclastics. Vegetation remains, charred by fire that was caused by the volcanic ash fall, were found in the lowermost part of the pyroclastics layer, on top of a paleosol. Charcoal fragments were dated to 18950-18830 cal BP (using INTCAL 09). Thus, pedon 2 developed since around 18.9 ka BP, whereas the development of the paleosol that was buried under the pyroclastics (pedon 3), was stopped at this time. Pedons 1 and 2 are Vitric Andosols, developed mainly from basic pyroclastics, as evidenced by the composition of rock fragments in the soils, comprising 78 / 81 mass % lapilli and 22 / 19 mass % gneiss fragments, respectively. Pedon 3 is a Cutanic Luvisol (Chromic) that developed entirely from gneiss fragments produced by the maar explosion. Lab data suggest increasing intensity of pedogenesis in the direction: Pedon 3 (paleosol) < Pedon 2 < Pedon 1, reflected e. g. in increasing Fed/Fet ratios, decreasing molar ratios of (Ca+K+Na)/Al, and decreasing pH. However, it needs to be considered that lapilli are more readily weatherable than gneiss fragments. The profile morphology of the paleosol, characterized by reddish-brown color (7.5YR), strong angular blocky structure and well-expressed illuvial clay

  12. The geothermal potential of the Campania volcanic district and new heat exchanger technologies for exploitation of highly urbanised areas.

    Carlino, S.; Somma, R.; Troiano, A.; Di Giuseppe, M. G.; Troise, C.; De Natale, G.


    The geothermal research in Campania region (Italy), started since the 1930, and continued until the '80 by the SAFEN, ENEL and AGIP companies. Such exploration activity highlighted that most of the volcanic districts of the Campania Region have a very high geothermal gradient and heat flow. In particular, inside the Campi Flegrei caldera and at Ischia island the geothermal gradient measured inside the deep wells reaches temperatures above 100° C between few tens and few hundreds of metres of depth, while the heat flow varies between 120-160 mWm-2 at Agnano and Mofete (Campi Flegrei main drill sites) to more than 500 mWm-2 at Ischia island (south-western sector). A general review of the available literature data (temperature at depth, stratigraphic sections, logs etc.) of the deep wells (down to 3 km b.s.l.) allowed us to quantify the geothermal potential (thermal and electric) of such district. The geothermal potential is about 6 GWy for the Campi Flegrei (Mofete and S. Vito sectors) and 11 GWy for the Ischia island (south-western sector) showing a geothermal reservoir with water and vapour dominant respectively. This results in strong potential interest for economic exploitation of the geothermal resource, both in the range of low-medium enthalpy at few hundreds of meters depth and of high enthalpy at depths of 1-2 km. In this study we try to model the effectiveness of new technologies of boreholes heat exchangers, which would allow to avoid fluid withdrawal, then strongly decreasing the environmental impact. The proposed technology consists of a double-pipe placed in a borehole heat exchange that can work coupled with an ORC. The two pipes, one inside the other, are located in the well in order to transfer the thermal energy to the working fluid during the descent in the external pipe and then go back through the internal pipe properly isolated. We propose a complete design of the borehole heat exchangers. The design activity is performed on a theoretical basis

  13. 大兴安岭哈拉哈河-绰尔河第四纪火山分期:K-Ar年代学与火山地质特征%Studies on Quaternary volcanism stages of Halaha river and Chaoer river area in the Great Xing'an Range: Evidence from K-Ar dating and volcanic geology features

    樊祺诚; 赵勇伟; 李大明; 武颖; 隋建立; 郑德文


    34 Quaternary volcanoes are distributed along a Quaternary NE strike belt in Halaha river and Chaoer river volcanic field. The lava flow, characterized by alkali olivine basalts, cover an area of 400km2. Based on studies on the volcanic field characteristics, in conjunction with geological dating by K-Ar, it is identified that the volcanism occurred in four periods; Early Pleistocene, Middle Pleistocene, Late Pleistocene and Holocene. Basalts of Early Pleistocene, mostly mantled by the later volcanic rocks, are distributed in the margin and valleys of the volcanic field. Middle Pleistocene, the most volcanic active period in this area, witnessed the formation of more than half of Quaternary volcanoes and lava spreading. Moderate volcanism occurred in Late Pleistocene which produced a small amount of volcanic deposits. Volcanic activities are strengthened again in Holocene Period, characterized by strongly explosive explosion, widespread lava flow and well-keeping lava landforms features.%大兴安岭中部哈拉哈河-绰尔河第四纪火山区分布有34座火山,这些火山总体呈北东向带状分布,火山岩分布面积约400 km2,岩性主要为碱性橄榄玄武岩.根据火山地质特征,结合火山岩K-Ar测年结果,哈拉哈河-绰尔河第四纪火山可进一步划分为早、中、晚更新世和全新世4期.早更新世火山岩,由于被后期火山岩覆盖,主要分布于火山区周边和出露在河谷中.中更新世火山活动最强,不论火山数量(27座)还是熔岩流规模都超过该区第四纪火山的一半以上.晚更新世时期火山活动趋弱,火山活动范围缩小,只局限于小范围区域.全新世火山活动又进入新的高峰期,强爆破式喷发和规模宏大的熔岩流,以及保存完好的熔岩流地貌是全新世火山之特点.

  14. An evaluation of the bioavailability and bioaccumulation of selected metals occurring in a wetland area on the volcanic island of Guam, Western Pacific Ocean

    Bob Wilson; Brian Pyatt; Gary Denton


    This initial research examines the presence,distribution and bioavailability of copper,chromium,nickel,manganese and iron in a wetland area of southern Guam.The research sites are within an area covered with saporite,a soil type derived from volcanic deposits on the island.Leaf tissue of Pandanus tectorius was extracted and analysed to determine the bioaccumulation of the target metals.Metal accumulation at sites considered aerobic and anaerobic was investigated together with an attempt to correlate actual accumulation of the target metals in the plant tissue with a recognised bioavailability indicator,in this case,three step sequential extraction scheme.Manganese was found to be accumulated in relatively high concentrations and to a lesser extent copper was also accumulated.Chromium,nickel and iron however exhibited very low accumulation factors.Accumulation of manganese in particular was significantly affected by aerobic conditions whereas the converse effect was experienced by copper.Significant correlation between various steps of a Sequential Extraction Scheme (SES) and actual accumulation was not achieved although the degree of aerobic conditions at each site and soil pH did affect concentrations of metals extracted by differing steps of SES.Results obtained suggest that further research in the area should be undertaken using different plant species and tissues.

  15. Mineralization and Geochemical Exploration in Volcanic- Plotonic Area of Halakabad Village (Sabzevar, Regarding to Cu-Porphyry Deposits

    Panahi Shahri, M.


    Full Text Available The investigated area is located 30 Km south of Sabzevar in Halakabad village. Geological phenomenons in area follow a trend of NW-SE. Mineralization consists of metallic and non-metallic (kaolin mineralization. Disseminated and veinlet mineralization is generally associated with argillic alteration type. Pyrite is the most widespread type of sulfide mineralization in Halakabad occurrences. It usually displays a euhedral habit and have occurred at least in two generations. Calcopyrite is common in veinlets although in minor amounts. Secondary sulfuric acid weathering of the ore has generated huge surficial amounts of oxide and sulfate minerals which of hematite and jarosite are the most abundant. Geochemical exploration was conducted over both drainage geochemistry and rock geochemistry. Results show that some of the stream sediments have higher concentrations of Copper and Zinc than normal. This anomalies maches with monzonite outcrops in area. The chip rock geochemical data shows highest values in west of halakabad mine for Cu and Zn respectively 500 and 900 ppm. These data represents that all samples collected from surficial areas of east of area contain lower concentrations of Copper while sulfide mineralization is more than the other parts. Presence of favorable alteration system in region, presence of monzonite subvolcanic intrusions and regional geological criteria indicates a possible Cu-Au porphyry system in Halakabad area.

  16. Application of Clinopyroxene Chemistry to Interpret the Physical Conditions of Ascending Magma, a Case Study of Eocene Volcanic Rocks in the Ghohrud Area (North of Isfahan

    Mohammad Sayari


    Full Text Available Introduction Volcanic rocks with a porphyritic texture have experienced two crystallization stages. The first is slow, resulting in phenocrysts, and the second, which took place at, or near the surface, or during intrusion into a cooler body of rock, result in a groundmass of glass, or fine crystals. The pressure and temperature history of a magma during crystallization is recorded in the chemical composition of the phenocrysts during both stages. These phenocrysts provide valuable data about the physicochemical conditions of the parent magma during the process of crystallization. The composition of clinopyroxene (cpx reflects not only the chemical condition and therefore the magmatic series, but also the physical conditions, i.e., temperature and pressure of a magma at the time when clinopyroxene crystallized. The Ghohrud area lies in the middle part of the Urumieh-Dokhtar Magmatic Arc , which is part of a much larger magmatic province extending in a vast region of convergence between Arabia and Eurasia north of the Zagros-Bitlis suture zone (Dilek et al., 2010. In the Ghohrud area, north of Isfahan, exposed Eocene volcanic rocks belong to the first pulse of Cenozoic volcanism of Iran (Sayari, 2015, ranging in composition from andesitic basalt to basalt. The basaltic rocks of the Ghohrud area are composed mainly of plagioclase phenocrysts surrounded by smaller crystals of clinopyroxene in a groundmass of microlites, glass and opaques. In this study, the clinopyroxene and plagioclase of these rocks were analyzed in order to estimate the physicochemical conditions of the parent magmas. Results Clinopyroxene and plagioclase phenocrysts of nineteen samples were analyzed with the electron microprobe. The chemical compositions of the clinopyroxenes were used to estimate both the chemical evolution and temperature and pressure conditions of the magmas during crystallization, using SCG, a specialized software for clinopyroxene thermobarometry (Sayari

  17. InSAR techniques for reliable deformation estimation in volcanic areas and a first glance of Tandem-DEM accuracy - test site El Hierro Island

    Cong, X.; Eineder, M.; Fritz, T.


    The accuracy and availability of deformation measurements using InSAR techniques is limited due to decorrelation effects, atmospheric disturbances and the SAR side-looking geometry (layover and shadowing). In this talk, we present our recent research and achievements on advanced InSAR techniques in order to retrieve reliable deformation signals from active volcanoes using high resolution TerraSAR-X (TSX) images. Another highlight of this talk is the evaluation of an experimental TanDEM-X (TDX) RawDEM with a resolution of approximately 6 m in order to compensate the topographic phase. A volcanic test site which is currently highly active -El Hierro- has been selected to demonstrate the developed techniques: 1) PSI processing in volcanic areas using high resolution TSX images; 2) Mitigation of atmospheric delay distortions; 3) Fusion of multi-geometrical PSI clouds. In order to measure the deformation from 2011 to 2013 at El Hierro [1], two stacks of stripmap TSX Mission data have been acquired, one in ascending orbit and one in descending. Each stack has more than 25 scenes. More than 1.5 million PSs have been detected (SCR>3.0 dB). The stratified atmospheric delay for each acquisition has been integrated for the PSI reference network and, afterwards, interpolated and compensated for all PSs. A linear deformation model has been assumed for PSI processing. For the descending orbit stack, a relative deformation from -21.7 to 131.8 mm/y from Sep. 2011 to Jan. 2013 with respect to a reference point located on the northeast coast has been measured. On the one hand, the spatial variation of the deformation has a good agreement with the seismicity distribution [1]. On the other hand, the deformation magnitude agrees with in-situ GPS measurements [2]. In ascending orbit, the linear deformation rate varies from -22.8 to 90.9 mm/y. This different range of value is due to a scene acquired on Feb. 2010, which has been included in order to obtain the pre-seismic deformation

  18. Volcanic gas

    McGee, Kenneth A.; Gerlach, Terrance M.


    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  19. Geochemistry and petrogenesis of anorogenic basic volcanic-plutonic rocks of the Kundal area, Malani Igneous Suite, western Rajasthan, India

    A Krishnakanta Singh; G Vallinayagam


    The Kundal area of Malani Igneous Suite consists of volcano-plutonic rocks. Basalt flows and gabbro intrusives are associated with rhyolite. Both the basic rocks consist of similar mineralogy of plagioclase, clinopyroxene as essential and Fe-Ti oxides as accessories. Basalt displays sub-ophitic and glomeroporphyritic textures whereas gabbro exhibits sub-ophitic, porphyritic and intergrannu- lar textures. They show comparable chemistry and are enriched in Fe, Ti and incompatible ele- ments as compared to MORB/CFB. Samples are enriched in LREE and slightly depleted HREE patterns with least significant positive Eu anomalies. Petrographical study and petrogenetic mod- eling of [Mg]-[Fe], trace and REE suggest cogenetic origin of these basic rocks and they probably derived from Fe-enriched source with higher Fe/Mg ratio than primitive mantle source. Thus, it is concluded that the basic volcano-plutonic rocks of Kundal area are the result of a low to moderate degree (> 30%) partial melting of source similar to picrite/komatiitic composition. Within plate, anorogenic setting for the basic rocks of Kundal area is suggested, which is in conformity with the similar setting for Malani Igneous Suite.

  20. Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes

    Herrera, Christian, E-mail: [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Custodio, Emilio [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Chong, Guillermo [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Lambán, Luis Javier [Geological Institute of Spain (IGME), Zaragoza (Spain); Riquelme, Rodrigo; Wilke, Hans [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Jódar, Jorge [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Urrutia, Javier; Urqueta, Harry [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Sarmiento, Alvaro [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); and others


    Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200 mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water–rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ{sup 18}O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. - Highlights: • Recent volcanism formations play a key role in producing recharge. • Groundwater can flow across local

  1. Large area crop inventory experiment crop assessment subsystem software requirements document


    The functional data processing requirements are described for the Crop Assessment Subsystem of the Large Area Crop Inventory Experiment. These requirements are used as a guide for software development and implementation.

  2. The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area

    E. Priolo


    Full Text Available During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy, the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km, such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions.

  3. Geochemistry and petrogenesis of anorogenic basic volcanic-plutonic rocks of the Kundal area, Malani Igneous Suite, western Rajasthan, India

    Krishnakanta Singh, A.; Vallinayagam, G.


    The Kundal area of Malani Igneous Suite consists of volcano-plutonic rocks. Basalt flows and gabbro intrusives are associated with rhyolite. Both the basic rocks consist of similar mineralogy of plagioclase, clinopyroxene as essential and Fe-Ti oxides as accessories. Basalt displays sub-ophitic and glomeroporphyritic textures whereas gabbro exhibits sub-ophitic, porphyritic and intergrannular textures. They show comparable chemistry and are enriched in Fe, Ti and incompatible elements as compared to MORB/CFB. Samples are enriched in LREE and slightly depleted HREE patterns with least significant positive Eu anomalies. Petrographical study and petrogenetic modeling of [Mg]-[Fe], trace and REE suggest cogenetic origin of these basic rocks and they probably derived from Fe-enriched source with higher Fe/Mg ratio than primitive mantle source. Thus, it is concluded that the basic volcano-plutonic rocks of Kundal area are the result of a low to moderate degree (conformity with the similar setting for Malani Igneous Suite.

  4. 五大连池老黑山火山弹和喷发柱动力学模拟%Simulation on the Dynamic Process of Volcanic Bombs and Plumes of Laoheishan Volcano in Wudalianchi Area

    李永生; 刘永顺; 张招崇; 聂保锋; 张东阳


    The volcanic eruption is a complex fluid dynamic process of gas, liquid and solid mixtures. A correct understanding of this process is the key factor to study the volcanic eruption. Eject and Plumeria softwares can be good simulations for dynamic processes of volcanic bombs and plumes during real volcanic eruption. On the basis of detailed investigation of volcanic bombs, volcanic debris and the published data of Laoheishan volcano in Wudalianchi area, this study evaluated dynamic processes of Laoheishan volcanic bombs and plumes using Eject and Plumeria softwares. The results show that the bombs ejected from Laoheishan volcano can reach a maximum height of 530 m and a maximum horizontal distance of 1,000 m when ejection angle is 45°; the maximum height of its volcanic plume is 4. 7 km, and the plume head radius is 2. 3 km. Through the discussion of the eruption scale and the ratio of volcanic ashes, it can be concluded that Laoheishan volcano is a small mafic eruption, and its effect on the environment is small.%火山喷发是一个气体、液体和固体混合物的复杂的流体动力学过程.正确理解这个过程是研究火山喷发的关键因素.Eject和Plumeria软件可以很好地模拟现实火山喷发过程中火山弹和喷发柱的动力学过程.在详细调查五大连池老黑山地区火山弹、火山碎屑物和整理已有数据的基础上,运用Eject和Plumeria软件对老黑山火山的火山弹和喷发柱进行了动力学模拟.结果表明:老黑山火山喷发的火山弹喷射最大高度为530 m,喷射角度45.时喷射水平距离最远为1000m,喷发柱最大高度为4.7 km,喷发柱半径为2.3 km.通过对其喷发规模和火山灰构成比例的探讨,认为老黑山火山喷发属于镁铁质火山小型喷发,对环境的影响范围有限.

  5. Inorganic particles in the skin of inhabitants of volcanic areas of Central America: their possible immunomodulatory influence in leishmaniasis and leprosy.

    Convit, J; Ulrich, M; Castillo, J; De Lima, H; Pérez, M; Caballero, N; Hung, J; Arana, B; Pérez, P


    We have evaluated biopsies from patients with atypical nodular and typical ulcerated lesions of cutaneous leishmaniasis, from leishmanin reactions and skin from normal individuals from Nicaragua, Honduras and Guatemala for the presence of inorganic particles using confocal microscopy with a polarised light source and conventional histopathological techniques. Analysis by semiquantitative confocal microscopy permitted the demonstration of significantly larger numbers of particles in atypical lesions. Silica and aluminium, important components of these particles, were less abundant in particles from normal skin. The histology of these atypical lesions, characterised by 'naked' sarcoidal granulomas with epithelioid differentiation but very few lymphocytes, was very similar to the histological reaction observed after 14 days in persisting inflammation at leishmanin skin test sites. The presence of these unusual lesions in areas of Central American countries characterised by the presence of large amounts of volcanic ash, as well the unexpectedly low prevalence of leprosy in Central America, suggest that environmental factors may contribute significantly to the frequency and clinical manifestations of these infections. Among possible environmental features, the presence of inorganic particles with immunomodulatory properties in the skin may be a significant factor.

  6. Revision, calibration, and application of the volume method to evaluate the geothermal potential of some recent volcanic areas of Latium, Italy

    Doveri, Marco; Lelli, Matteo; Raco, Brunella [Institute of Geosciences and Georesources, CNR, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa (Italy); Marini, Luigi [Laboratory of Geochemistry, Dip.Te.Ris., University of Genova, Corso Europa 26, I-16132 Genova (Italy); Institute of Geosciences and Georesources, CNR, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa (Italy)


    The volume method is used to evaluate the productive potential of unexploited and minimally exploited geothermal fields. The distribution of P{sub CO2} in shallow groundwaters delimits the geothermal fields. This approach is substantiated by the good correspondence between zones of high CO{sub 2} flux, and the areal extension of explored geothermal systems of high enthalpy (Monte Amiata and Latera), medium enthalpy (Torre Alfina) and low enthalpy (Viterbo). Based on the data available for geothermal fields either under exploitation or investigated by long-term production tests, a specific productivity of 40 t h{sup -1} km{sup -3} is assumed. The total potential productivity for the recent volcanic areas of Latium is about 28 x 10{sup 3} t h{sup -1}, with 75% from low-enthalpy geothermal fields, 17% from medium-enthalpy systems, and 8% from high-enthalpy reservoirs. The total extractable thermal power is estimated to be 2220-2920 MW, 49-53% from low-enthalpy geothermal fields, 28-32% from medium-enthalpy systems, and 19-20% from high-enthalpy reservoirs. (author)

  7. Interstratified arkosic and volcanic rocks of the Miocene Spanish Canyon Formation, Alvord Mountain area, California: descriptions and interpretations

    Buesch, David C.


    The Spanish Canyon Foundation in the Alvord Mountain area, California, varies from about 50 to 120 m thick and records the interstratification of arkosic sandstone and conglomerate with tuffaceous deposits and lava flows. In the lower third of the formation, arkosic sandstone and conglomerate are interstratified with tuffaceous deposits. Some tuffs might have been deposited as primary, nonwelded to partially welded ignimbrites or fallout tephra. Many of the tuffaceous deposits represent redeposited material that formed tuffaceous sandstone, and many of these deposits contain arkosic grains that represent mixing of different source matieral. Arkosic sandstone, and especially conglomerate (some with maximum clast lengths up to 1 m), represent intermittent incursions of coarser plutoniclastic fan deposits into other finer grained and mostly volcaniclastic basin deposits. After deposition of the 18.78 Ma Peach Spring Tuff, the amount of tuffaceous material decreased. The upper two-thirds of the formation has arkosic sandstone and conglomerate interstratified with two olivine basalt lave flows. locally, conglomerate clasts in this part of the section have maximum lengths up to 1 m. Many tuffaceous and arkosic sandstone beds of the Spanish Canyon Formation have tabular to broad (low-relief) lenticular geometry, and locally, some arkosic conglomerate fills channels as much as 1.5 m deep. These bedforms are consistent with deposition in medial to distal alluvial-fan or fluvial environments; some finer-grained deposits might have formed in lacustrine environments.

  8. From high quality seismic data acquisition in remote volcanic area to fast data distribution to scientific community: The UnderVolc project on Piton de la Fournaise volcano

    Brenguier, Florent; Kowalski, Philippe; Pequegnat, Catherine; Lauret, Frédéric; Cougoulat, Glenn; Boissier, Patrice; Catherine, Philippe


    Piton de la Fournaise basaltic volcano (La Réunion island, France) is one of the most active volcano in the world with an average of one eruption every year. This volcano is thus an ideal case study for research projects focusing on studying magmatic, seismic and deformation processes occurring in volcanic areas. The UNDERVOLC (UNDERstanding VOLCanic Processes) research project main goal is to provide high quality 3-component broadband continuous seismic data to an amount of about 30 volcano-seismologists from different international research teams (including Japan and New-Zealand). This data acquisition system is moreover dedicated to the monitoring of Piton de la Fournaise volcano by providing real-time seismic data to the Piton de la Fournaise volcanological Observatory/IPGP. The network consists of 21 fully autonomous stations composed of CMG40-T seismometers associated to high dynamic digitizers and linked to wireless digital radio stations. The seismic signal is sent by UDP protocol to the observatory through a network of wireless LAN over large distances (~10 km) and possibly through the internet to the Observatory. The acquisition system at the observatory is composed of: 1-An Earthworm system (USGS - ISTI - CERI) with a Q330 to Earthworm data acquisition module (6 permanent stations from the observatory) 2-An Apollo server system (Nanometrics) for 15 stations (for which seismometers and digitizers belong to the French national pool of portable seismic instruments Sismob, INSU-CNRS) In both case, requests are sent back to the stations in case of loss of udp packets. This system allows us producing miniseed files every hour. Since September 2009, the full dataset has less then 1 % of gaps. In order to provide a fast data access to the scientific community, we synchronize our dataset every night with the SISMOB datacenter located in France (LGIT, Grenoble). After a quality check, seed data volumes are produced and distributed by standard NETDC requests from

  9. Trace elements and REE fractionation in subsoils developed on sedimentary and volcanic rocks: case study of the Mt. Vulture area, southern Italy

    Mongelli, Giovanni; Paternoster, Michele; Rizzo, Giovanna; Sinisi, Rosa


    There is an increasing interest in the distribution of rare earth elements (REEs) within soils, primarily as these elements can be used to identify pedogenetic processes and because soils may be future sources for REE extraction, despite much attention should be paid to the protection and preservation of present soils. Here, we evaluate the processes that control the distribution of REEs in subsoil horizons developed over differing lithologies in an area of low anthropogenic contamination, allowing estimates of the importance of source rocks and weathering. Specifically, this study presents new data on the distribution of REEs and other trace elements, including transition and high-field-strength elements, in subsoils developed on both Quaternary silica-undersaturated volcanic rocks and Pliocene siliciclastic sedimentary rocks within the Mt. Vulture area of the southern Apennines in Italy. The subsoils in the Mt. Vulture area formed during moderate weathering (as classified using the chemical index of alteration) and contain an assemblage of secondary minerals that is dominated by trioctahedral illite with minor vermiculite. The REEs, high-field-strength elements, and transition metals have higher abundances in subsoils that developed from volcanic rocks, and pedogenesis caused the Mt. Vulture subsoils to have REE concentrations that are an order of magnitude higher than typical values for the upper continental crust. This result indicates that the distribution of REEs in soils is a valuable tool for mineral exploration. A statistical analysis of inter-elemental relationships indicates that REEs are concentrated in clay-rich fractions that also contain significant amounts of low-solubility elements such as Zr and Th, regardless of the parent rock. This suggests that low-solubility refractory minerals, such as zircon, play a significant role in controlling the distribution of REEs in soils. The values of (La/Yb)N and (Gd/Yb)N fractionation indices are dependent on

  10. Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.

    Herrera, Christian; Custodio, Emilio; Chong, Guillermo; Lambán, Luis Javier; Riquelme, Rodrigo; Wilke, Hans; Jódar, Jorge; Urrutia, Javier; Urqueta, Harry; Sarmiento, Alvaro; Gamboa, Carolina; Lictevout, Elisabeth


    Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water-rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ(18)O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano.

  11. Reassessment of petrogenesis of Carboniferous–Early Permian rift-related volcanic rocks in the Chinese Tianshan and its neighboring areas

    Linqi Xia


    Full Text Available The Carboniferous−Early Permian rift-related volcanic successions, covering large areas in the Chinese Tianshan and its adjacent areas, make up a newly recognized important Phanerozoic large igneous province in the world, which can be further divided into two sub-provinces: Tianshan and Tarim. The regional unconformity of Lower Carboniferous upon basement or pre-Carboniferous rocks, the ages (360–351 Ma of the youngest ophiolite and the peak of subduction metamorphism of high pressure–low temperature metamorphic belt and the occurrence of Ni-Cu-bearing mafic-ultramafic intrusion with age of ∼352 Ma and A-type granite with age of ∼358 Ma reveal that the final closure of the Paleo-Asian Ocean might take place in the Early Mississippian. Our summation shows that at least four criteria, being normally used to identify ancient asthenosphere upwelling (or mantle plumes, are met for this large igneous province: (1 surface uplift prior to magmatism; (2 being associated with continental rifting and breakup events; (3 chemical characteristics of asthenosphere (or plume derived basalts; (4 close links to large-scale mineralization and the uncontaminated basalts, being analogous to those of many “ore-bearing” large igneous provinces, display Sr-Nd isotopic variations between plume and EM1 geochemical signatures. These suggest that a Carboniferous asthenosphere upwelling and an Early Permian plume played the central role in the generation of the Tianshan–Tarim (central Asia large igneous province.

  12. Multidisciplinary approach for the characterization of landslides in volcanic areas - a case study from the Palma Sola-Chiconquiaco Mountain Range, Mexico

    Wilde, Martina; Rodríguez Elizarrarás, Sergio R.; Morales Barrera, Wendy V.; Schwindt, Daniel; Bücker, Matthias; Flores Orozco, Adrián; García García, Emilio; Pita de la Paz, Carlos; Terhorst, Birgit


    The Palma Sola-Chiconquiaco mountain range, situated in the State of Veracruz, Mexico, is highly susceptible to landslides, which is evidenced by the high frequency of landslide events of different sizes. The study area is located near the Gulf of Mexico coastline in the eastern sector of the Trans Mexican Volcanic Belt. There, landslide triggers are intense rainfalls related to tropical storms and hurricanes. Steeper slopes are commonly affected by rockfalls, whereas moderate slopes, covered by massive slope deposits, are affected by shallow as well as deep seated landslides. Some of the landslides in the slope deposits reach dimensions of more than 1000 m in length and depths of over 30 m. The heterogeneous parent material as well as older slide masses hamper the detailed characterization of the involved materials. Therefore, in this study, a multidisciplinary approach is applied that integrates geomorphological, geological, and geophysical data. The aim is the reconstruction of process dynamics by analyzing the geomorphological situation and subsurface conditions before and after the event. The focus lies on the identification of past landslide areas, which represent areas with high susceptibility for the reactivation of old slide masses. Furthermore, the analysis of digital terrain models, generated before the landslide event, indicate initial movements like extension cracks, which are located close to the current scarp area. In order to characterize the subsurface of slide masses geophysical investigations are applied. The geophysical survey consists of a total of nine profiles covering relevant key features of the large affected area. Along these profiles, electrical resistivity tomography (ERT) and seismic refraction tomography (SRT) data were collected. Both, electrical and seismic images reveal a sharp contrast between relatively loose and dry material of the slide mass (high resistivities and low seismic velocities) and the former land surface that is

  13. 徐东地区营城组一段火山喷发模式特征%Mode Characteristics of Volcanic Eruption of the Member 1 of Yingcheng Formation in Xudong Area in Songliao Basin

    陈欢庆; 胡永乐; 冉启全; 衣丽萍; 许磊


    According to the structural environment and cycle characteristic of the volcanic eruption, original magma, volcanic rock feature, and the types of the volcanic eruption, the mode characteristics of volcanic eruption of volcanic gas reservoir of the Member 1 of Yingcheng Formation in Xudong Area in Xushen Gas Field are studied. The results indicate that the aimed stratum in study areas was formed under an intraplate setting and the fractures cut-through the base plays a definitive role. The study stratum fall into three gyrations of 1 and II and III from bottom to top. Gyre I correspond to Yd III and Gyre II corresponds YC]II' and YCiII2 and Gyre III corresponds YCiI1 and YCiI2. The stratum in study areas mainly developed fissure-center eruption, the center eruption taking the secondary place. The conditions of oil source rock and accumulation and rock cap are excellent. The volcanic eruption mode controlls development characteristics of different types of volcanic lithofacies. The favorable areas mainly develop in the high-order bit of eruption facies near the volcanic crater and lower part and upper part and top part sub-facies of overflow facies and volcanic neck sub-facies of volcanic channels facies.%从火山喷发的构造环境、火山喷发旋回特征出发,结合原始岩浆来源、火山岩岩性特征、火山喷发类型等,总结了徐深气田徐东地区营城组一段火山喷发模式,分析了其对储层的影响.结果表明,切穿基底的深大断裂在火山喷发中起着决定性的作用.目的层自下而上划分为3个旋回,旋回Ⅰ对应YC1 Ⅲ,旋回Ⅱ对应YC1 Ⅱ1和YC1Ⅱ2,旋回Ⅲ对应小层YC1Ⅰ1和YC1Ⅰ2.火山喷发以裂隙-中心式喷发为主,中心式喷发为辅.火山喷发模式控制着不同类型火山岩相的发育特征.靠近火山口的爆发相的高部位、溢流相下部亚相、项部亚相、上部亚相、火山通道相的火山颈亚相等是有利的开发区域.

  14. Geochemical Characteristics and Geological Significance of the Kafang Alkaline Volcanic Rocks in Gejiu Area, Yunnan Province%云南个旧卡房碱性火山岩地球化学特征及意义

    张海; 方维萱; 杜玉龙


    Indosinian volcanism in the Gejiu area was divided into three phases: the Anisian Phase, the Early Ladinian Phase, and the Later Ladinian Phase-Norian Phase in the Middle Traissic Epoch. The Anisian alkali volcanic rocks were closely related to the Sn-Cu mineralization in the Kafang copper-tin deposit. The lithological and geochemical studies showed that the volcanic rocks contain 42.22% to 46.61% of SiO2, 8.61% to 18.19% of MgO, 3.52% to 7.52% of K2O+Na2O (K2O/Na2O=0.28 to 25.95) and 2.03% to 3.51% of TiO2. These volcanic rocks belong to alkalic ultrobasic volcanic rocks, and they are rich in high field-strength elements (Nb, Ta) and large-ion lithophile elements (Rb, Ba, Sr, Cs). At the same time, rare earth elements in these volcanic rocks are LREE-enriched and HREE-defected with right-inclined patterns, with obvious Eu anomalies and weak Ce negative anomalies. It may be indicated that diagenetic process of the Kafang alkali volcanic rocks might be mainly influenced by partial melting of mantle, and not obviously influenced by crustal contamination based on their geochemical features. The magmatic source area of these volcanic rocks might have derived from the partial melting of phlogopite-rich (or hornblende-rich) mantle peridotite. Moreover, the Kafang volcanic rocks share geochemical characteristics with the ocean island basalts (OIB). Based on the lithological and geochemical characteristics of the Kafang alkali volcanic rocks, these volcanic rocks might be formed in a geotectonic settings of the back-arc rift basin, and they may provide original source for the Kafang copper-tin deposit in Yunnan province, China.%个旧地区印支期的火山作用主要有三期,即中三叠世安尼期、拉丁尼克早期和拉丁尼克晚期-诺利克期。通过对与成矿关系密切的卡房铜锡矿安尼期碱性火山岩的岩相学、地球化学研究发现: SiO2含量为42.22%~46.61%, MgO含量为8.61%~18.19%, K2O+Na2O值为3.52%~7.52%, K2O/Na2O值为0

  15. Submarine volcanoes along the Aegean volcanic arc

    Nomikou, Paraskevi; Papanikolaou, Dimitrios; Alexandri, Matina; Sakellariou, Dimitris; Rousakis, Grigoris


    The Aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research. The basic data including swath bathymetric maps, air-gun profiles, underwater photos and samples analysis have been presented along the four main volcanic groups of the arc. The description concerns: (i) Paphsanias submarine volcano in the Methana group, (ii) three volcanic domes to the east of Antimilos Volcano and hydrothermal activity in southeast Milos in the Milos group, (iii) three volcanic domes east of Christiana and a chain of about twenty volcanic domes and craters in the Kolumbo zone northeast of Santorini in the Santorini group and (iv) several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the Nisyros group. The tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them. The NE-SW direction is dominant in the Santorini and Nisyros volcanic groups, located at the eastern part of the arc, where strike-slip is also present, whereas NW-SE direction dominates in Milos and Methana at the western part, where co-existence of E-W disrupting normal faults is observed. The volcanic relief reaches 1100-1200 m in most cases. This is produced from the outcrops of the volcanic centers emerging usually at 400-600 m depth and ending either below sea level or at high altitudes of 600-700 m on the islands. Hydrothermal activity at relatively high temperatures observed in Kolumbo is remarkable whereas low temperature phenomena have been detected in the Santorini caldera around Kameni islands and in the area southeast of Milos. In Methana and Nisyros, hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations.

  16. Geochemistry and spatial distribution of late-Paleozoic mafic volcanic rocks in the surrounding areas of the Gonghe Basin: Implications for Majixueshan triple-junction and east Paleotethyan archipelagic ocean


    The late-Paleozoic mafic volcanic rocks occurring in the surrounding areas of the Gonghe basin are distributed in the A'nyêmaqên ophiolite zone, Zongwulong tectonic zone and Kuhai-Saishitang volcanic zone. The mafic volcanics in the A'nyêmaqên zone formed an ancient ridge-centered hotspot around the Majixueshan OIB, the Kuhai-Saishitang mafic rocks consist of E-MORB and continental rift basalts and the Zongwulong volcanic rocks are enriched N-MORB. The regionally low Nb/U and Ce/Pb ratios reflect the influence of the OIB material on the mafic magma source. From geochemistry, spatial distribution and tectonic relationship of the mafic rocks, an ancient triple-junction centered at the Majixueshan can be inferred. The existence of the Kuhai-Saishitang aulacogen may have provided a tectonic channel for the Majixueshan OIB materials metasomatizing the magma source for the Zongwulong rocks. The formation of the triple-junction and the rifting of the Zongwulong zone have separated the orogens and massifs in the region.

  17. Age and location of volcanic centers less than or equal to 3. 0 m. y. old in Arizona, New Mexico, and the Trans-Peco area of West Texas

    Aldrich, M.J.; Laughlin, A.W.


    This map is one of a series of maps designed for hot dry rock geothermal assessment in Arizona, New Mexico, and the Trans-Peco area of the west Texas. The 3.0 m.y. cutoff age was selected because original heat has probably largely dissipated in older rocks. The location of volcanic centers is more important to geothermal resource assessment than the location of their associated volcanic rocks; however, ages have been determined for numerous flows far from their source. Therefore, the distribution of all volcanic rocks less than or equal to 3.0 m.y. old, for which there is at least one determined age, are shown. Location of the volcanic vents and rocks were taken from Luedke and Smith (1978). Ages were obtained from the original literature in all cases except for McKee and others (1974), Silberman and others (1976), Ulrich and McKee (1976), and Wolfe and McKee (1976). The abstract by McKee and others (1974) lists only the ages of various rocks they dated, so locations were taken from Luedke and Smith (1978). The dates of Silberman and others (1976), Ulrich and McKee (1976), and Wolfe and McKee (1976) are taken from written communications cited by Luedke and Smith (1978); therefore, both references are shown on the map for those ages.

  18. Sedimentary Record of the Proterozoic Changchengian Volcanic Events in Beijing and Its Neighbouring Area%北京及邻区长城纪火山事件的沉积记录

    和政军; 宋天锐


    The volcanic rocks of the Proterozoic Dahongyu Formation mainlydistribute in Pinggu County of Beijing and Jixian county of Tianjin about 600 km2 with 718 m and 490 m of the maximum thickness in the both areas. More than 40 paleo-carters were survived in the areas. The types of volcanic rocks mainly are potassic basalts and trachyte. Sedimentary facies related to volcanic event in the Middle Proterozoic Dahongyu Formation in Beijing and its neighboring area mainly include two basic types: siliceous-sand-carbonate mixed facies and pyroclastic gravity flow deposit, in which the later can be divided into pyroclastic basic surge and volcanic breccia - carbonate mixed deposit. Siliceous-sand-carbonate mixed facies: the rock types of this facies include white and light-blue siliceous-bearing quazites, light-blue sandy silicalites, blue-grey tuff, siliceous dolomites, intraclast-shaped silicalites and geltexture siliealites. Siliceous-sand-carbonate mixed facies widely distribute in the NE basin axis inclined to the NW side. Preliminary results of analysis, according to characteristics of rocks, geochemistry and sedimentation, show that enormous siliceous sediments of the Dahongyu Formation mainly originated from the submarine volcanic eruption in the temporary time. Pyroclastic basic surges: Basic surges directly cover on basalts and occur around the paleo-craters. They are composed of coarse sand-grade pyroclastic rocks with large-scale dune-like cross bedding and poly-grade bedding, fine sand-silt-grade pyroclastic rocks and tuff shales. The pyroclastic basic surge was caused by sea water surging in small range, which was related to release of remnant steam bursting to seal of volcanic craters. Volcanic breccia-carbonate mixed facies: Volcanic breccia-carbonate generally is single bed placed in between dolomites. In the beds breccia components are composed of sedimentary rocks (40~60%) and of basalts and tractytes (30~40%). According to analysis of sedimentary

  19. Modeling of methane bubbles released from large sea-floor area: Condition required for methane emission to the atmosphere

    Yamamoto, A.; Yamanaka, Y.; Tajika, E.


    Massive methane release from sea-floor sediments due to decomposition of methane hydrate, and thermal decomposition of organic matter by volcanic outgassing, is a potential contributor to global warming. However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from the sea-floor to reach the atmosphere. Massive methane release from a large sea-floor area would result in methane-saturated seawater, thus some methane would reach the atm...

  20. 塔河地区火山岩类型、分布与主控因素%Types, distribution and main controlling factors of volcanic rocks in Tahe area

    唐跃; 崔泽宏; 王靓靓


    通过岩心观察、地球化学方法、测井地震资料综合分析,认为塔河地区火山岩主要发育英安岩和玄武岩两大类.火山喷发主要以裂隙式喷发、侵出和溢流为主,形成塔河地区大面积火山熔岩流.火山岩的分布由西南向东北逐渐减薄,其分布主要受控于以下几个因素:①盐体覆盖区及其周缘附近,晚海西运动盐体的活动明显控制上覆火山岩岩体形态展布和分布特征,受盐体活动影响,火山岩主要残留于盐边凹陷地带和盐体覆盖区南翼,盐间凹陷火山岩厚度相对较大,盐隆地带残缺较大;②北部地区火山岩分布主要受基底喷发裂隙控制;③盐体南部斜坡地带玄武岩可能从塔里木盆地塔中地区溢流而来.%Based on core observation, geochemical exploration and a comprehensive analysis of logging and seismic data, the authors hold that that two types of volcanic rocks, I.e., dacite and basalt, occur in Tahe area of Tarim basin, that fissure eruption, extrusion and overflow made up the main forms of volcanic eruption, and that lava flow resulted in the formation of extensive volcanic rocks in Tahe area. The distribution of volcanic rocks is characterized by gradual thinning from southwest to northeast,controlled by the following factors: ①in salt body covered area and its vicinity, the activity of salt body during late Hercynian movement significandy controlled the shape and distribution of the overlying volcanic rock, as evidenced by the facts that the residual volcanic rocks are mainly found in salt-edge sags and the south wing of the area covered with salt body and that these rocks are thickest in sags between salt bodies and thinnest in the salt bulge area which experienced uplifting and erosion;② the distribution of the volcanic rocks in the north of the study area is mainly controlled by the basement fractures; ③the volcanic rocks in the southern slope area of the salt body might have been derived

  1. Efficient Exploration and Development of Carboniferous Volcanic Gas Field in Kelameili Area in Junggar Basin%克拉美丽石炭系火山岩气田的高效勘探开发

    董雪梅; 徐怀民; 贺陆明; 任军民; 吴静


    Volcanic oil-gas exploration in Junggar basin started in 1950's.In recent years,through comprehensive researches of hydrocarbon accumulation conditions of the Carboniferous volcanic reservoirs,Ludong-Wucaiwan area is chosen as major exploration target to carry out systematic studies and make technological breakthrough,thus deepening the knowledge of volcanic reservoir,establishing the exploration thought of reservoir controls dominated by volcanic rock body,based on which the matched technologies were developed,and the breakthroughs have been made in drilling of volcanic rock body as main target in Dinan bulge.A hundred billion cubic meters of Kelameili gas field with both source and reservoir in Carboniferous system was proved in two years and the first large-scale integrated volcanic gas field in Junggar basin is discovered.Up to now,it has been brought into the scale and efficient production.The Carboniferous volcanic reservoirs have become an important domain for oil-gas exploration in Junggar basin.%准噶尔盆地火山岩油气勘探始于20世纪50年代,近年来通过准噶尔盆地石炭系油气成藏条件综合研究,优选陆东—五彩湾地区作为勘探主战场,展开针对石炭系火山岩的系统研究和技术攻关,不断深化成藏认识,确立了以火山岩岩体控藏的勘探思路,研发了与之相应的配套技术,在滴南凸起上以火山岩岩体为主要目标展开钻探获得突破,探明了千亿方的石炭系自生自储的克拉美丽气田,形成准噶尔盆地第一个大型整装火山岩气田,并已实现规模高效开发。石炭系火山岩已经成为准噶尔盆地油气勘探的重要领域。

  2. 33 CFR 151.69 - Operating requirements: Discharge of garbage outside special areas.


    ... of garbage outside special areas. 151.69 Section 151.69 Navigation and Navigable Waters COAST GUARD... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage Pollution and Sewage § 151.69 Operating requirements: Discharge of garbage outside special areas. (a)...

  3. 33 CFR 151.71 - Operating requirements: Discharge of garbage within special areas.


    ... of garbage within special areas. 151.71 Section 151.71 Navigation and Navigable Waters COAST GUARD... on Environmental Protection to the Antarctic Treaty as it Pertains to Pollution from Ships Garbage Pollution and Sewage § 151.71 Operating requirements: Discharge of garbage within special areas. (a) When...

  4. Researches of Fractal Features of Radial River System in the Changbaishan Volcanic Area%长白山火山区放射状水系分形特征研究

    张丽红; 刘永顺; 彭年; 聂保锋


    The values of fractal dimension of river system reflect their degree of development and complexity of river channel. On the basis of remote sensing data, fractal geometry and image analysis software, the values of boxcounting fractal dimension for the radial river system of Changbaishan volcanic area are calculated,and carried out statistical calculations in EXCEL. The region can be subdivided into four distinct areas characterized by different geomorpholo-gic features and their values of fractal dimension also can be obtained respectively. The results show that the maximum value D= 1. 425 of fractal dimension of river system in the Changbai-shan volcanic area appears in the west part of volcanic area while the minimum D = 1. 212 in the eastern part. The differences of fraetal dimension values of the four distinct areas show the erosive degree of the fluvial landform, but in the whole, the degree of development is still in the primary stage. The contributing factors of fluvial landform are related with volcanic topography,volcanic activities and their forming fracture, mass movement and rock of underlying surface,among which the fracture is main.%水系分维反映了水系的发育程度,体现了河道的复杂程度.以TM遥感数据和分形几何理论为基础,应用图像分析软件ENVI对长白山火山区水系进行了盒维数计算,经统计分析得到了该区四个子区域水系及整个区域水系的分维数.结果表明:长白山火山区水系分维数西部最大D=1.425,东部最小D=1.212;四个分区分维数的差异直接反映了其流域地貌侵蚀发育的程度,但从整体上来看仍处于河流地貌发育的初级阶段.流域地貌的发育状态与火山地形、火山活动及其形成的断裂构造、块体运动以及下覆地面岩性有关,其中断裂构造是最主要的.

  5. Operational Safety Requirements and Operating Specification Documentation compliance instrumentation matrices: 200 East Area Tank Farms

    Story, D.R.


    This document contains information about matrices complied of instrumentation used to comply with the existing Operational Safety Requirements from Safety Analysis Reports and Operating, Specification Documentation requirements for 200 East Area Tank Farms. These matrices contain the primary instrumentation needed to comply with each OSR and/or OSD requirement as well as any backup instrumentation that may be used should the primary device be out of service. The referenced matrices are provided as attachments to this document.

  6. Paleoproterozoic (~1.88Ga felsic volcanism of the Iricoumé Group in the Pitinga Mining District area, Amazonian Craton, Brazil: insights in ancient volcanic processes from field and petrologic data

    Ronaldo Pierosan


    Full Text Available The Iricoumé Group correspond to the most expressive Paleoproterozoic volcanism in the Guyana Shield, Amazonian craton. The volcanics are coeval with Mapuera granitoids, and belong to the Uatumã magmatism. They have U-Pb ages around 1880 Ma, and geochemical signatures of α-type magmas. Iricoumé volcanics consist of porphyritic trachyte to rhyolite, associated to crystal-rich ignimbrites and co-ignimbritic fall tuffs and surges. The amount and morphology of phenocrysts can be useful to distinguish lava (flow and dome from hypabyssal units. The morphology of ignimbrite crystals allows the distinction between effusive units and ignimbrite, when pyroclasts are obliterated. Co-ignimbritic tuffs are massive, and some show stratifications that suggest deposition by current traction flow. Zircon and apatite saturation temperatures vary from 799°C to 980°C, are in agreement with most temperatures of α-type melts and can be interpreted as minimum liquidus temperature. The viscosities estimation for rhyolitic and trachytic compositions yield values close to experimentally determined melts, and show a typical exponential decay with water addition. The emplacement of Iricoumé volcanics and part of Mapuera granitoids was controlled by ring-faults in an intracratonic environment. A genesis related to the caldera complex setting can be assumed for the Iricoumé-Mapuera volcano-plutonic association in the Pitinga Mining District.O Grupo Iricoumé corresponde ao mais expressivo vulcanismo Paleoproterozóico do Escudo das Guianas, craton Amazônico. As rochas vulcânicas são coexistentes com os granitóides Mapuera, e pertencem ao magmatismo Uatumã. Possuem idades U-Pb em torno 1888 Ma, e assinaturas geoquímicas de magmas tipo-A. As vulcânicas do Iricoumé consistem de traquitos a riolitos porfiríticos, associados a ignimbritos ricos em cristal e tufos co-ignimbríticos de queda e surge. A quantidade e a morfologia dos fenocristais podem ser

  7. 大兴安岭诺敏河第四纪火山岩分期:岩石学、年代学与火山地质特征%Studies on Quaternary volcanism stages of Nuomin river area in the Great Xing'an Range: Evidence from petrology, K-Ar dating and volcanic geology features

    樊祺诚; 赵勇伟; 隋建立; 李大明; 武颖


    大兴安岭北段诺教河第四纪火山24座,分布于诺敏河及其支流毕拉河和甘河支流奎勒河,火山岩分布面积约600km2.诺敏河火山岩均属于钾质系列火山岩(K2O含量2%~4%,且K2O> Na2o-2%),类似于邻区五大连池-科洛钾质火山岩,具有来自类似的富钾地幔源区.但诺敏河火山岩的K2O含量明显低于五大连池-科洛火山岩的K2O含量(一般4%~6%).东北地区和内蒙东部处于中亚造山带东段,从古生代到新生代,多重构造-岩浆活动导致火山岩源区地球化学非均一性和火山岩的多样性.根据本文提出的火山岩K-Ar年龄(2.3 ~0.128Ma)及火山地质特征,可将诺敏河第四纪火山岩分为四期.早期(早更新世)火山活动主要沿诺敏河和奎勒河流域分布,火山产物多被晚期沉积物或火山产物所覆盖.中更新世保留的火山锥体及熔岩流是诺敏河第四纪火山产物的主体,表明是第四纪火山活动的高潮期.晚更新世-全新世火山活动限于毕拉河流域,典型的四方山火山和马鞍山火山是该时期火山活动的代表作,保留了较完好的火山地质地貌特征.从火山产物的时空展布,推测诺敏河第四纪火山活动有从东向西发展的趋势.%24 Quaternary volcanoes are distributed along IVnomin river and Kuile river area volcanic field ( NK for short) in the north of the Great Xing' an Range. With an area of 600 square kilometers, the volcanic rocks are characterized by potassic series (K2O =2% -4% , K2O > Na2O -2% ), which are similar with rocks in Wudalianchi-Keluo volcanic field (WK for short). Although NK and WK share the alike mantle source, volcanic rocks from NK are low in K2O than that from WK ( K2O = 4% ~6% ). During the Paleozoic and the Cenozoic, multiple tectonic and magmatic activities resulted in the heterogenous geochemistry in the magma source, and thus varied volcanic rocks were generated. Based on K-Ar dating (2.3 ~ 0. 128Ma) and

  8. Cenozoic volcanic rocks of Saudi Arabia

    Coleman, R.G.; Gregory, R.T.; Brown, G.F.


    The Cenozoic volcanic rocks of Saudi Arabia cover about 90,000 km2, one of the largest areas of alkali olivine basalt in the world. These volcanic rocks are in 13 separate fields near the eastern coast of the Red Sea and in the western Arabian Peninsula highlands from Syria southward to the Yemen Arab Republic.

  9. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and geometric considerations

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, İlkan; Çelik, H. Hamdi


    Volcanic ash particles are important components of explosive eruptions, and their surface textures are the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on geometric considerations (geometric surface area) and physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), which is a non-destructive method providing three-dimensional data, enabled the measurement of surface area and volume of individual ash particles. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging are similar, with surface area/volume ratios (SA/V) of 0.0368 and 0.0467, respectively. Ash particle surface textures show a large deviation from that of simple geometric forms, and an approximation both to spheres and ellipsoids do not seem adequate for the representation of ash surface. SEM stereoscopic and/or micro-CT imaging are here suggested as good candidate techniques for the characterization of textures on macro-pore regions of ash particles.

  10. An aggregation model for ash particles in volcanic clouds

    Costa, A.; Folch, A.; Macedonio, G.; Durant, A.


    A large fraction of fine ash particles injected into the atmosphere during explosive eruptions aggregate through complex interactions of surface liquid layers, electrostatic forces, and differences in particle settling velocities. The aggregates formed have a different size and density compared to primary particles formed during eruption which dramatically changes the dynamics of sedimentation from the volcanic cloud. Consequently, the lifetime of ash particles in the atmosphere is reduced and a distal mass deposition maximum is often generated in resulting tephra deposits. A complete and rigorous description of volcanic ash fallout requires the full coupling of models of volcanic cloud dynamics and dispersion, and ash particle transport, aggregation and sedimentation. Furthermore, volcanic ash transport models should include an aggregation model that accounts for the interaction of all particle size classes. The problem with this approach is that simulations would require excessively long computational times thereby prohibiting its application in an operational setting during an explosive volcanic eruption. Here we present a simplified model for ash particle transport and aggregation that includes the effects of water in the volcanic cloud and surrounding atmosphere. The aggregation model assumes a fractal relationship for the number of primary particles in aggregates, average sticking efficiency factors, and collision frequency functions that account for Brownian motion, laminar and turbulent fluid shear, and differential settling velocity. A parametric study on the key parameters of the model was performed. We implemented the aggregation model in the WRF+FALL3D coupled modelling system and applied it to different eruptions where aggregation has been recognized to play an important role, including the August and September 1992 Crater Peak eruptions and the 1980 Mt St Helens eruption. In these cases, mass deposited as a function of deposit area and the particle

  11. Volcanic hazard assessment in monogenetic volcanic fields

    Bartolini, Stefania


    [eng] One of the most important tasks of modern volcanology, which represents a significant socio-economic implication, is to conduct hazard assessment in active volcanic systems. These volcanological studies are aimed at hazard that allows to constructing hazard maps and simulating different eruptive scenarios, and are mainly addressed to contribute to territorial planning, definition of emergency plans or managing volcanic crisis. The impact of a natural event, as a volcanic eruption, can s...

  12. Volcanic hazard assessment for the Canary Islands (Spain) using extreme value theory, and the recent volcanic eruption of El Hierro

    Sobradelo, R.; Martí, J.; Mendoza-Rosas, A. T.; Gómez, G.


    The Canary Islands are an active volcanic region densely populated and visited by several millions of tourists every year. Nearly twenty eruptions have been reported through written chronicles in the last 600 years, suggesting that the probability of a new eruption in the near future is far from zero. This shows the importance of assessing and monitoring the volcanic hazard of the region in order to reduce and manage its potential volcanic risk, and ultimately contribute to the design of appropriate preparedness plans. Hence, the probabilistic analysis of the volcanic eruption time series for the Canary Islands is an essential step for the assessment of volcanic hazard and risk in the area. Such a series describes complex processes involving different types of eruptions over different time scales. Here we propose a statistical method for calculating the probabilities of future eruptions which is most appropriate given the nature of the documented historical eruptive data. We first characterise the eruptions by their magnitudes, and then carry out a preliminary analysis of the data to establish the requirements for the statistical method. Past studies in eruptive time series used conventional statistics and treated the series as an homogeneous process. In this paper, we will use a method that accounts for the time-dependence of the series and includes rare or extreme events, in the form of few data of large eruptions, since these data require special methods of analysis. Hence, we will use a statistical method from extreme value theory. In particular, we will apply a non-homogeneous Poisson process to the historical eruptive data of the Canary Islands to estimate the probability of having at least one volcanic event of a magnitude greater than one in the upcoming years. Shortly after the publication of this method an eruption in the island of El Hierro took place for the first time in historical times, supporting our method and contributing towards the validation of

  13. An emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas

    Liu Sheng


    Full Text Available Abstract: Purpose: Frequent sudden-onset disasters which have threatened the survival of human and the development of society force the public to pay an increasing attention to emergency management. A challenging task in the process of emergency management is emergency dispatch of reliefs. An emergency dispatch model considering the urgency of the requirement for reliefs in different disaster areas is proposed in this paper to dispatch reliefs reasonably and reduce the effect of sudden-onset disasters. Design/methodology/approach: Firstly, quantitative assessment on the urgency of the requirement for reliefs in different disaster areas is done by an evaluation method based on Fuzzy Comprehensive Evaluation and improved Evidence Reasoning which is proposed in this paper. And then based the quantitative results, an emergency dispatch model aiming to minimize the response time, the distribution cost and the unsatisfied rate of the requirement for reliefs is proposed, which reflects the requests of disaster areas under emergency, including the urgency of requirement, the economy of distribution and the equity of allocation. Finally, the Genetic Algorithm is improved based on the adaptive crossover and mutation probability function to solve the emergency dispatch model. Findings and Originality/value: A case that the Y hydraulic power enterprise carries on emergency dispatch of reliefs under continuous sudden-onset heavy rain is given to illustrate the availability of the emergency dispatch model proposed in this paper. The results show that the emergency dispatch model meets the distribution priority requirement of disaster area with the higher urgency, so thatreliefs are supplied more timely. Research limitations/implications: The emergency dispatch model faced to large scale sudden-onset disasters is complex. The quantity of reliefs that disaster area requires and the running time of vehicles are viewed as available information, and the problem

  14. Requirements and System Architecture for a Healthcare Wireless Body Area Network

    Hansen, Finn Overgaard; Toftegaard, Thomas Skjødeberg

    Wireless body area networks enable new opportunities for personal healthcare monitoring and personal healthcare applications. This paper presents a comprehensive set of requirements and challenges for building a wireless body area network to support diverse user groups and a corresponding set...... of an ASE-BAN test bed. The major goal for this test bed is to be a platform for research and experiments with development of an ultra-low power body area network including sensor, communication nodes, communication protocols and a body gateway component....... of healthcare applications. Based on the identified requirements, the paper presents an architecture for a wireless body area network and describes how this architecture is connected to an existing it-infrastructure supporting healthcare at home. Finally the paper presents our on-going research with development...

  15. Eco-environmental water requirement for wetlands in Huang-Huai-Hai Area, China


    Based on the related literature and the analysis of the relationship between wetland ecosystem and hydroperiod, the estimating and classifying methods of eco-environmental water requirement for wetlands are established. The data collected from Huang-Huai-Hai Area are from the electronic map (1∶250000) of China National Topographical Database of 1997 and the historical statistics since the 1980s.The results indicate that the minimum eco-environmental water requirement for wetlands is 16.98×109 m3 and the optimal one is 38.38×109 m3 in the studied area. For the five wetland nature reserves covered in the area, the values are 1.47×109 m3 and 3.31×109 m3 respectively. The comparisons of the mentioned minimum water requirement with the status water use, which is 17.05×109 m3 for wetland ecosystem (1997 as the status year), suggest that the water use has not met the minimum eco-environmental water requirement in the Haihe and Huanghe Basins of the studied area. However, the status water use guarantees and exceeds the minimum eco-environmental water requirement in the Shandong Peninsula and the Huaihe Basin. Based on the eco-environmental programming and water resource planning of the studied area, the study establishes the water requirement of the year of 2010, 2030, 2050, when the eco-environmental water requirement for wetlands is 18.30×109 m3, 21.64×109 m3 and 26.76×109 m3, respectively.

  16. Analysis of the variation of the compressibility index (Cc) of volcanic clays and its application to estimate subsidence in lacustrine areas

    Carreón-Freyre, D.; González-Hernández, M.; Martinez-Alfaro, D.; Solís-Valdéz, S.; Cerca, M.; Millán-Malo, B.; Gutiérrez-Calderón, R.; Centeno-Salas, F.


    An analysis of the deformation conditions of lacustrine materials deposited at three sites in the volcanic valley of the Mexico City is presented. Currently geotechnical studies assume that compressibility of granular materials decreases in depth due to the lithostatic load. That means that the deeper the sample the more rigid is supposed to be, this assumption should be demonstrated by a decreased Compression Index (Cc) in depth. Studies indicate that Mexico City clays exhibit brittle behaviour, and have high water content, low shear strength and variable Cc values. Furthermore, groundwater withdrawal below the city causes a differential decrease in pore pressure, which is related to the physical properties of granular materials (hydraulic conductivity, grain size distribution) and conditions of formation. Our results show that Cc for fine grain materials (lacustrine) can be vertically variable, particularly when soils and sediments are the product of different volcanic materials. Lateral and vertical variations in the distribution of the fluvio-lacustrine materials, especially in basins with recent volcanic activity, may be assessed by Cc index variations. These variations can also be related to differential deformation, nucleation and propagation of fractures and need to be considered when modelling land subsidence.

  17. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and Brunauer-Emmett-Teller (BET) model

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, Ä.°Lkan; Ćelik, H. Hamdi


    Volcanic ash particles are important components of explosive eruptions and their surface texture is the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of the volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on the geometric considerations (geometric surface area) and the physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), a non-destructive method providing three-dimensional data enabled the measurement of surface areas and volumes of individual ash particles. Specific surface area estimates for ash particles were also obtained using nitrogen as gas adsorbent and the BET (Brunauer-Emmett-Teller) model. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging overlaps with mean specific surface area results of 0.0167 and 0.0214 m2/g, respectively. However, ash particle surface textures present quite a deviation from that of their geometric forms and approximation to sphere and ellipsoid both seemed to be inadequate for representation of real ash surfaces. The higher surface area estimate (> 0.4 m2/g) obtained from the technique based on physical sorption of gases (BET model here) was attributed to its capability for surface areas associated even with angstrom-sized pores. SEM stereoscopic and/or micro-CT imaging were suggested for characterization of textures on macro-pore regions of ash particles.

  18. Climatic impact of volcanic eruptions

    Rampino, Michael R.


    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  19. Models of volcanic eruption hazards

    Wohletz, K.H.


    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  20. Heat flow in vapor dominated areas of the Yellowstone Plateau volcanic field: implications for the thermal budget of the Yellowstone Caldera

    Hurwitz, Shaul; Harris, Robert; Werner, Cynthia Anne; Murphy, Fred


    Characterizing the vigor of magmatic activity in Yellowstone requires knowledge of the mechanisms and rates of heat transport between magma and the ground surface. We present results from a heat flow study in two vapor dominated, acid-sulfate thermal areas in the Yellowstone Caldera, the 0.11 km2 Obsidian Pool Thermal Area (OPTA) and the 0.25 km2 Solfatara Plateau Thermal Area (SPTA). Conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at >600 locations and from laboratory measurements of soil properties. The conductive heat output is 3.6 ± 0.4 MW and 7.5 ± 0.4 MW from the OPTA and the SPTA, respectively. The advective heat output from soils is 1.3 ± 0.3 MW and 1.2 ± 0.3 MW from the OPTA and the SPTA, respectively and the heat output from thermal pools in the OPTA is 6.8 ± 1.4 MW. These estimates result in a total heat output of 11.8 ± 1.4 MW and 8.8 ± 0.4 MW from OPTA and SPTA, respectively. Focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor. Extrapolation of the average heat flux from the OPTA (103 ± 2 W·m−2) and SPTA (35 ± 3 W·m−2) to the ~35 km2 of vapor dominated areas in Yellowstone yields 3.6 and 1.2 GW, respectively, which is less than the total heat output transported by steam from the Yellowstone Caldera as estimated by the chloride inventory method (4.0 to 8.0 GW).

  1. 42 CFR 486.306 - OPO service area size designation and documentation requirements.


    ... HEALTH AND HUMAN SERVICES (CONTINUED) STANDARDS AND CERTIFICATION CONDITIONS FOR COVERAGE OF SPECIALIZED SERVICES FURNISHED BY SUPPLIERS Requirements for Certification and Designation and Conditions for Coverage... information: (1) The names of counties (or parishes in Louisiana) served or, if the service area includes...

  2. The minimum area requirements (MAR) for giant panda: an empirical study.

    Qing, Jing; Yang, Zhisong; He, Ke; Zhang, Zejun; Gu, Xiaodong; Yang, Xuyu; Zhang, Wen; Yang, Biao; Qi, Dunwu; Dai, Qiang


    Habitat fragmentation can reduce population viability, especially for area-sensitive species. The Minimum Area Requirements (MAR) of a population is the area required for the population's long-term persistence. In this study, the response of occupancy probability of giant pandas against habitat patch size was studied in five of the six mountain ranges inhabited by giant panda, which cover over 78% of the global distribution of giant panda habitat. The probability of giant panda occurrence was positively associated with habitat patch area, and the observed increase in occupancy probability with patch size was higher than that due to passive sampling alone. These results suggest that the giant panda is an area-sensitive species. The MAR for giant panda was estimated to be 114.7 km(2) based on analysis of its occupancy probability. Giant panda habitats appear more fragmented in the three southern mountain ranges, while they are large and more continuous in the other two. Establishing corridors among habitat patches can mitigate habitat fragmentation, but expanding habitat patch sizes is necessary in mountain ranges where fragmentation is most intensive.

  3. Requirements analysis and design for implementation of a satellite link for a local area computer network

    Lorentzen, Richard B.


    Approved for public release; distribution is unlimited The purpose of this thesis is to provide naval computer students with a basic knowledge on Very Small Aperture Terminal (VSAT) satellite technology and to define the hardware and software requirements at the interface between a VSAT and a Local Area Network (LAN). By restricting a computer network to terrestrial links, a vast amount of knowledge is not accessed because either the terrestrial links can't access the information or the...

  4. B4G local area: high level requirements and system design

    Mogensen, Preben; Pajukoski, Kari; Raaf, Bernhard


    A next generation Beyond 4G (B4G) radio access technology is expected to become available around 2020 in order to cope with the exponential increase of mobile data traffic. In this paper, research motivations and high level requirements for a B4G local area concept are discussed. Our suggestions...... on the design of the B4G system as well as on the choice of its key technology components are also presented....

  5. Recurrence models of volcanic events: Applications to volcanic risk assessment

    Crowe, B.M. [Los Alamos National Lab., Las Vegas, NV (United States); Picard, R.; Valentine, G. [Los Alamos National Lab., NM (United States); Perry, F.V. [New Mexico Univ., Albuquerque, NM (United States)


    An assessment of the risk of future volcanism has been conducted for isolation of high-level radioactive waste at the potential Yucca Mountain site in southern Nevada. Risk used in this context refers to a combined assessment of the probability and consequences of future volcanic activity. Past studies established bounds on the probability of magmatic disruption of a repository. These bounds were revised as additional data were gathered from site characterization studies. The probability of direct intersection of a potential repository located in an eight km{sup 2} area of Yucca Mountain by ascending basalt magma was bounded by the range of 10{sup {minus}8} to 10{sup {minus}10} yr{sup {minus}1 2}. The consequences of magmatic disruption of a repository were estimated in previous studies to be limited. The exact releases from such an event are dependent on the strike of an intruding basalt dike relative to the repository geometry, the timing of the basaltic event relative to the age of the radioactive waste and the mechanisms of release and dispersal of the waste radionuclides in the accessible environment. The combined low probability of repository disruption and the limited releases associated with this event established the basis for the judgement that the risk of future volcanism was relatively low. It was reasoned that that risk of future volcanism was not likely to result in disqualification of the potential Yucca Mountain site.

  6. Improving the AODV Protocol to Satisfy the Required Level of Reliability for Home Area Networks

    Hossein Jafari Pozveh


    Full Text Available For decades, the structure of existing power grids has not changed. It is an old structure that depends heavily on fossil fuel as an energy source, and in the future, this is likely to be critical in the field of energy. To solve these problems and to make optimal use of energy resources, a new concept is proposed, called Smart Grid. Smart Grid is an electric power distribution automation system, which can provide a two-way flow of electricity and information between power plants and consumers. The Smart Grid communications infrastructure consists of different network components, such as Home Area Network (HAN, Neighborhood Area Network (NAN and Wide Area Network (WAN. Achieving the required level of reliability in the transmission of information to all sections, including the HAN, is one of the main objectives in the design and implementation of Smart Grid. This study offers a routing protocol by considering the parameters and constraints of HAN, which, by improving AODV routing protocol, achieves the level of required reliability for data transmission in this network. These improvements include: making table-driven AODV routing protocol, extending the routing protocol to compute multiple paths in a route discovery, simplification and providing the effect of HAN parameters. The results of the NS2 simulation indicate that applying this improved routing protocol in the HAN, satisfies the required level of reliability of the network, which is over 98%.

  7. Evaluation of solar sludge drying alternatives by costs and area requirements.

    Kurt, Mayıs; Aksoy, Ayşegül; Sanin, F Dilek


    Thermal drying is a common method to reach above 90% dry solids content (DS) in sludge. However, thermal drying requires high amount of energy and can be expensive. A greenhouse solar dryer (GSD) can be a cost-effective substitute if the drying performance, which is typically 70% DS, can be increased by additional heat. In this study feasibility of GSD supported with solar panels is evaluated as an alternative to thermal dryers to reach 90% DS. Evaluations are based on capital and O&M costs as well as area requirements for 37 wastewater treatment plants (WWTPs) with various sludge production rates. Costs for the supported GSD system are compared to that of conventional and co-generation thermal dryers. To calculate the optimal costs associated with the drying system, an optimization model was developed in which area limitation was a constraint. Results showed that total cost was minimum when the DS in the GSD (DS(m,i)) was equal to the maximum attainable value (70% DS). On average, 58% of the total cost and 38% of total required area were associated with the GSD. Variations in costs for 37 WWTPs were due to differences in initial DS (DS(i,i)) and sludge production rates, indicating the importance of dewatering to lower drying costs. For large plants, GSD supported with solar panels provided savings in total costs especially in long term when compared to conventional and co-generation thermal dryers.

  8. Structural controls on fluid circulation at the Caviahue-Copahue Volcanic Complex (CCVC) geothermal area (Chile-Argentina), revealed by soil CO2 and temperature, self-potential, and helium isotopes

    Roulleau, Emilie; Bravo, Francisco; Pinti, Daniele L.; Barde-Cabusson, Stéphanie; Pizarro, Marcela; Tardani, Daniele; Muñoz, Carlos; Sanchez, Juan; Sano, Yuji; Takahata, Naoto; de la Cal, Federico; Esteban, Carlos; Morata, Diego


    Natural geothermal systems are limited areas characterized by anomalously high heat flow caused by recent tectonic or magmatic activity. The heat source at depth is the result of the emplacement of magma bodies, controlled by the regional volcano-tectonic setting. In contrast, at a local scale a well-developed fault-fracture network favors the development of hydrothermal cells, and promotes the vertical advection of fluids and heat. The Southern Volcanic Zone (SVZ), straddling Chile and Argentina, has an important, yet unexplored and undeveloped geothermal potential. Studies on the lithological and tectonic controls of the hydrothermal circulation are therefore important for a correct assessment of the geothermal potential of the region. Here, new and dense self-potential (SP), soil CO2 and temperature (T) measurements, and helium isotope data measured in fumaroles and thermal springs from the geothermal area located in the north-eastern flank of the Copahue volcanic edifice, within the Caviahue Caldera (the Caviahue-Copahue Volcanic Complex - CCVC) are presented. Our results allowed to the constraint of the structural origin of the active thermal areas and the understanding of the evolution of the geothermal system. NE-striking faults in the area, characterized by a combination of SP, CO2, and T maxima and high 3He/4He ratios (up to 8.16 ± 0.21Ra, whereas atmospheric Ra is 1.382 × 10- 6), promote the formation of vertical permeability preferential pathways for fluid circulation. WNW-striking faults represent low-permeability pathways for hydrothermal fluid ascent, but promote infiltration of meteoric water at shallow depths, which dilute the hydrothermal input. The region is scattered with SP, CO2, and T minima, representing self-sealed zones characterized by impermeable altered rocks at depth, which create local barriers for fluid ascent. The NE-striking faults seem to be associated with the upflowing zones of the geothermal system, where the boiling process

  9. Volcanic caves of East Africa - an overview

    Jim W. Simons


    Full Text Available Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and areas are shortly reported.

  10. Deriving required model structures to predict global wildfire burned area from multiple satellite and climate observations

    Forkel, Matthias; Dorigo, Wouter; Lasslop, Gitta; Teubner, Irene; Chuvieco, Emilio; Thonicke, Kirsten


    Vegetation fires have important effects on human infrastructures and ecosystems, and affect atmospheric composition and the climate system. Consequently, it is necessary to accurately represent fire dynamics in global vegetation models to realistically represent the role of fires in the Earth system. However, it is unclear which model structures are required in global vegetation/fire models to represent fire activity at regional to global scales. Here we aim to identify required structural components and necessary complexities of global vegetation/fire models to predict spatial-temporal dynamics of burned area. For this purpose, we developed the SOFIA (satellite observations for fire activity) modelling approach to predict burned area from several satellite and climate datasets. A large ensemble of SOFIA models was generated and each model was optimized against observed burned area data. Models that account for a suppression of fire activity at wet conditions result in the highest performances in predicting burned area. Models that include vegetation optical depth data from microwave satellite observations reach higher performances in predicting burned area than models that do not include this dataset. Vegetation optical depth is a proxy for vegetation biomass, density and water content and thus indicates a strong control of vegetation states and dynamics on fire activity. We further compared the best performing SOFIA models with the global process-oriented vegetation/fire model JSBACH-SPITFIRE, and with the GFED and Fire_CCI burned area datasets. SOFIA models outperform JSBACH-SPITFIRE in predicting regional variabilities of burned area. We further applied the best SOFIA model to identify controlling factors for burned area. The results indicate that fire activity is controlled by regionally diverse and complex interactions of human, vegetation and climate factors. Our results demonstrate that the use of multiple observational datasets on climate, hydrological

  11. Volcanic studies at Katmai


    The Continental Scientific Drilling Program (CSDP) is a national effort supported by the Department of Energy, the US Geological Survey, and the National Science Foundation. One of the projects proposed for the CSDP consists of drilling a series of holes in Katmai National Park in Alaska to give a third dimension to the model of the 1912 eruption of Novarupta, and to investigate the processes of explosive volcanism and hydrothermal transport of metals (Eichelberger et al., 1988). The proposal for research drilling at Katmai states that ``the size, youth, elevated temperature, and simplicity of the Novarupta vent make it a truly unique scientific target.`` The National Park Service (NPS), which has jurisdiction, is sympathetic to aims of the study. However, NPS wishes to know whether Katmai is indeed uniquely suited to the research, and has asked the Interagency Coordinating Group to support an independent assessment of this claim. NPS suggested the National Academy of Sciences as an appropriate organization to conduct the assessment. In response, the National Research Council -- the working arm of the Academy -- established, under the aegis of its US Geodynamics Committee, a panel whose specific charge states: ``The proposed investigation at Katmai has been extensively reviewed for scientific merit by the three sponsoring and participating agencies. Thus, the scientific merit of the proposed drilling at Katmai is not at issue. The panel will review the proposal for scientific drilling at Katmai and prepare a short report addressing the specific question of the degree to which it is essential that the drilling be conducted at Katmai as opposed to volcanic areas elsewhere in the world.``

  12. Minimum area requirements for an at-risk butterfly based on movement and demography.

    Brown, Leone M; Crone, Elizabeth E


    Determining the minimum area required to sustain populations has a long history in theoretical and conservation biology. Correlative approaches are often used to estimate minimum area requirements (MARs) based on relationships between area and the population size required for persistence or between species' traits and distribution patterns across landscapes. Mechanistic approaches to estimating MAR facilitate prediction across space and time but are few. We used a mechanistic MAR model to determine the critical minimum patch size (CMP) for the Baltimore checkerspot butterfly (Euphydryas phaeton), a locally abundant species in decline along its southern range, and sister to several federally listed species. Our CMP is based on principles of diffusion, where individuals in smaller patches encounter edges and leave with higher probability than those in larger patches, potentially before reproducing. We estimated a CMP for the Baltimore checkerspot of 0.7-1.5 ha, in accordance with trait-based MAR estimates. The diffusion rate on which we based this CMP was broadly similar when estimated at the landscape scale (comparing flight path vs. capture-mark-recapture data), and the estimated population growth rate was consistent with observed site trends. Our mechanistic approach to estimating MAR is appropriate for species whose movement follows a correlated random walk and may be useful where landscape-scale distributions are difficult to assess, but demographic and movement data are obtainable from a single site or the literature. Just as simple estimates of lambda are often used to assess population viability, the principles of diffusion and CMP could provide a starting place for estimating MAR for conservation.

  13. A decision-making framework to model environmental flow requirements in oasis areas using Bayesian networks

    Xue, Jie; Gui, Dongwei; Zhao, Ying; Lei, Jiaqiang; Zeng, Fanjiang; Feng, Xinlong; Mao, Donglei; Shareef, Muhammad


    The competition for water resources between agricultural and natural oasis ecosystems has become an increasingly serious problem in oasis areas worldwide. Recently, the intensive extension of oasis farmland has led to excessive exploitation of water discharge, and consequently has resulted in a lack of water supply in natural oasis. To coordinate the conflicts, this paper provides a decision-making framework for modeling environmental flows in oasis areas using Bayesian networks (BNs). Three components are included in the framework: (1) assessment of agricultural economic loss due to meeting environmental flow requirements; (2) decision-making analysis using BNs; and (3) environmental flow decision-making under different water management scenarios. The decision-making criterion is determined based on intersection point analysis between the probability of large-level total agro-economic loss and the ratio of total to maximum agro-economic output by satisfying environmental flows. An application in the Qira oasis area of the Tarim Basin, Northwest China indicates that BNs can model environmental flow decision-making associated with agricultural economic loss effectively, as a powerful tool to coordinate water-use conflicts. In the case study, the environmental flow requirement is determined as 50.24%, 49.71% and 48.73% of the natural river flow in wet, normal and dry years, respectively. Without further agricultural economic loss, 1.93%, 0.66% and 0.43% of more river discharge can be allocated to eco-environmental water demands under the combined strategy in wet, normal and dry years, respectively. This work provides a valuable reference for environmental flow decision-making in any oasis area worldwide.

  14. A Volcanic Hydrogen Habitable Zone

    Ramirez, Ramses M.; Kaltenegger, Lisa


    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  15. The volcanic and tectonic history of Enceladus

    Kargel, J.S.; Pozio, S.


    Enceladus has a protracted history of impact cratering, cryo-volcanism, and extensional, compressional, and probable strike-slip faulting. It is unique in having some of the outer Solar System's least and most heavily cratered surfaces. Enceladus' cratering record, tectonic features, and relief elements have been analyzed more comprehensively than done previously. Like few other icy satellites, Enceladus seems to have experienced major lateral lithospheric motions; it may be the only icy satellite with global features indicating probable lithospheric convergence and folding. Ridged plains, 500 km across, consist of a central labyrinthine ridge complex atop a broad dome surrounded by smooth plains and peripheral sinuous ridge belts. The ridged plains have few if any signs of extension, almost no craters, and an average age of just 107 to 108 years. Ridge belts have local relief ranging from 500 to 2000 m and tend to occur near the bottoms of broad regional troughs between swells. Our reanalysis of Peter Thomas' (Dermott, S. F., and P. C. Thomas, 1994, The determination of the mass and mean density of Enceladus from its observed shape, Icarus, 109, 241-257) limb profiles indicates that high peaks, probably ridge belts, also occur in unmapped areas. Sinuous ridges appear foldlike and are similar to terrestrial fold belts such as the Appalachians. If they are indeed folds, it may require that the ridged plains are mechanically (perhaps volcanically) layered. Regional topography suggests that folding may have occurred along zones of convective downwelling. The cratered plains, in contrast to the ridged plains, are heavily cratered and exhibit extensional structures but no obvious signs of compression. Cratered plains contain a possible strike-slip fault (Isbanir Fossa), along which two pairs of fractures seem to have 15 km of right-lateral offset. The oldest cratered plains might date from shortly after the formation of the saturnian system or the impact disruption and

  16. Experimental generation of volcanic lightning

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Kueppers, Ulrich; Scheu, Bettina; Dingwell, Donald B.


    Ash-rich volcanic plumes that are responsible for injecting large quantities of aerosols into the atmosphere are often associated with intense electrical activity. Direct measurement of the electric potential at the crater, where the electric activity in the volcanic plume is first observed, is severely impeded, limiting progress in its investigation. We have achieved volcanic lightning in the laboratory during rapid decompression experiments of gas-particle mixtures under controlled conditions. Upon decompression (from ~100 bar argon pressure to atmospheric pressure), loose particles are vertically accelerated and ejected through a nozzle of 2.8 cm diameter into a large tank filled with air at atmospheric conditions. Because of their impulsive character, our experiments most closely represent the conditions encountered in the gas-thrust region of the plume, when ash is first ejected from the crater. We used sieved natural ash with different grain sizes from Popocatépetl (Mexico), Eyjafjallajökull (Iceland), and Soufrière Hills (Montserrat) volcanoes, as well as micrometric glass beads to constrain the influence of material properties on lightning. We monitored the dynamics of the particle-laden jets with a high-speed camera and the pressure and electric potential at the nozzle using a pressure transducer and two copper ring antennas connected to a high-impedance data acquisition system, respectively. We find that lightning is controlled by the dynamics of the particle-laden jet and by the abundance of fine particles. Two main conditions are required to generate lightning: 1) self-electrification of the particles and 2) clustering of the particles driven by the jet fluid dynamics. The relative movement of clusters of charged particles within the plume generates the gradient in electrical potential, which is necessary for lightning. In this manner it is the gas-particle dynamics together with the evolving particle-density distribution within different regions of

  17. Volcanic Supersites as cross-disciplinary laboratories

    Provenzale, Antonello; Beierkuhnlein, Carl; Giamberini, Mariasilvia; Pennisi, Maddalena; Puglisi, Giuseppe


    Volcanic Supersites, defined in the frame of the GEO-GSNL Initiative, are usually considered mainly for their geohazard and geological characteristics. However, volcanoes are extremely challenging areas from many other points of view, including environmental and climatic properties, ecosystems, hydrology, soil properties and biogeochemical cycling. Possibly, volcanoes are closer to early Earth conditions than most other types of environment. During FP7, EC effectively fostered the implementation of the European volcano Supersites (Mt. Etna, Campi Flegrei/Vesuvius and Iceland) through the MED-SUV and FUTUREVOLC projects. Currently, the large H2020 project ECOPOTENTIAL (2015-2019, 47 partners, contributes to GEO/GEOSS and to the GEO ECO Initiative, and it is devoted to making best use of remote sensing and in situ data to improve future ecosystem benefits, focusing on a network of Protected Areas of international relevance. In ECOPOTENTIAL, remote sensing and in situ data are collected, processed and used for a better understanding of the ecosystem dynamics, analysing and modelling the effects of global changes on ecosystem functions and services, over an array of different ecosystem types, including mountain, marine, coastal, arid and semi-arid ecosystems, and also areas of volcanic origin such as the Canary and La Reunion Islands. Here, we propose to extend the network of the ECOPOTENTIAL project to include active Volcanic Supersites, such as Mount Etna and other volcanic Protected Areas, and we discuss how they can be included in the framework of the ECOPOTENTIAL workflow. A coordinated and cross-disciplinary set of studies at these sites should include geological, biological, ecological, biogeochemical, climatic and biogeographical aspects, as well as their relationship with the antropogenic impact on the environment, and aim at the global analysis of the volcanic Earth Critical Zone - namely, the upper layer of the Earth

  18. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?


    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  19. Ecological Water Requirement Estimates for Typical Areas in the Huaihe Basin

    DONG Xin; DU Pengfei; TONG Oingyuan; CHEN Jining


    Aquatic ecosystems require ecological water allocation to prevent from being damaged by natural disasters and undue exploitation. This paper discusses and estimates the ecological water requirements (EWRs) of typical areas in the Huaihe Basin to determine rational allocations of water resources and pro-mote regional improvements of the ecological environment. The main river course, including Hongze Lake and Nansi Lake, was selected as the study subject. Calculational methods for the river and lake EWRs were based on the reasonableness of the results and data availability. The monthly guarantee rate method was used to calculate monthly, flood period, non-flood period, and annual EWRs for the main river course and the main tributaries at two different guarantee rates. The minimum water level method was used to calculate annual EWRs for Hongze Lake and the upper and lower Nansi Lake of 1.521×109 m3, 0.637×109 m3, and 0.306×109 m3. The results were used to evaluate the rationality of the quantity of water resources allocated to ecological uses in the Huaihe Basin during 1998-2003. The result shows that the present water resource allocations in the Huaihe Basin cannot satisfy the basic ecological requirements for some years, especially years with less precipitation.

  20. Characterizing long-term radon concentration changes in a geothermal area for correlation with volcanic earthquakes and reservoir temperatures: A case study from Mt. Aso, southwestern Japan

    Koike, Katsuaki; Yoshinaga, Tohru; Asaue, Hisafumi


    The purpose of this study is to characterize in detail the temporal changes in Rn (radon-222) concentration in soil gases near fumaroles and clarify its correlation with volcanic earthquakes and temperatures in two geothermal reservoirs. Mt. Aso crater in southwest Japan, which has two reservoirs on its western side estimated by magnetotelluric survey to be at about 2 km in depth, was selected for this study. For the long-term survey, the α scintillation counter method was used weekly for 12.5 years at the three hot springs within a 2-km range. Rn concentrations were calculated using the CRAS method, a calculation method that considers radioactive equilibrium or nonequilibrium state of the soil gas. Rn concentrations generally showed similar fluctuation patterns among the sites. CRAS was used as a new indicator for evaluating the age of the soil gas. This age corresponds to the elapsed time determined from the generation of Rn based on the measurement of the numbers of atoms of Rn and its daughter 218Po at the start of measurement. In comparing the Rn data with the history of earthquakes in the Aso caldera, volcanic seismicity was identified as a major controlling factor in the sudden increase and decrease in Rn concentration as a function of age. For more precise detections of change, Rn concentrations were measured continuously at one site by pumping soil gas from a borehole and using an ionization chamber over 2.5 years. Five chemical components (He, H2, N2, CH4, and CO2) were then measured by gas chromatography at 1-week intervals. Because Rn concentrations are affected strongly by atmospheric temperatures, the residual components were obtained by subtracting the trend of the components from the original data. Chemical component data were used to estimate the temperature and pressure in the reservoir at the site; temperatures ranged from 229 to 280 °C, (average 265 °C, average pressure 80 MPa). Residual Rn concentrations showed a clear correlation with

  1. Episodic Volcanism and Geochemistry in Western Nicaragua

    Saginor, I.; Carr, M. J.; Gazel, E.; Swisher, C.; Turrin, B.


    The active volcanic arc in western Nicaragua is separated from the Miocene arc by a temporal gap in the volcanic record, during which little volcanic material was erupted. Previous work suggested that this gap lasted from 7 to 1.6 Ma, during which volcanic production in Nicaragua was limited or nonexistent. Because the precise timing and duration of this gap has been poorly constrained, recent fieldwork has focused on locating samples that may have erupted close to or even during this apparent hiatus in activity. Recent 40Ar/39Ar dates reveal pulses of low- level episodic volcanism at 7 Ma and 1 Ma between the active and Miocene arcs with current volcanism beginning ~350 ka. In addition, sampling from an inactive area between Coseguina and San Cristobal yielded two distinct groupings of ages; one of Tamarindo age (13 Ma) and the other around 3.5 Ma-the only samples of that age collected on-strike with the active arc. This raises the possibility the bases of the other active volcanoes contain lavas that are older than expected, but have been covered by subsequent eruptions. The Miocene arc differs from the active arc in Central America in several ways, with the latter having higher Ba/La and U/Th values due to increased slab input and changes in subducted sediment composition. Analysis of sample C-51 and others taken from the same area may shed light on the timing of this shift from high to low Ba/La and U/Th values. More importantly, it may help explain why the arc experienced such a dramatic downturn in volcanic production during this time. We also report 25 new major and trace element analyses that shed some light on the origins of these minor episodes of Nicaraguan volcanism. These samples are currently awaiting Sr and Nd isotopic analyses.

  2. Volcanic characteristics and rule of hydrocarbon accumulation of Shuanglong area in Lishu faulted depression%梨树断陷双龙地区火山发育特征及油气成藏规律

    朴勇信; 刘长利; 朱建伟; 李烨


    Cretaceous Huoshiling Formation of the Shuanglong area in Lishu faulted depression of Songliao Basin developed two types of eruptive volcanos,including the central vent eruption and fissure eruption.They dif-fer in terms of the development scale and hydrocarbon accumulation.The central vent eruption has the characteris-tics of violent activity,long duration,extensive distribution scale of volcanic rocks,large thickness and the lithol-ogy progressively shift from the mafic to the neutral.The fissure eruption has the characteristics of weak activity, short duration,less distribution scale of volcanic rocks,thin thickness and the lithology is mainly neutral.The central vent eruption volcano is adjacent to lake basin,forming the environment of volcanic-lacustrine deposit. With the alternate deposition of volcanic rocks,conglomerate and deep and semi-deep lake mudstone,the Hu-oshiling Formation of central vent eruption area has good association pattern of source rocks,reservoirs and caps rock,and forms self-generation and self-bearing combination of source-reservoir-cap.The fissure eruption volcano is far away from the lake basin and the distribution of volcanic rocks has no directly contact with the deep lacustrine facies mudstone,coupled with poor reservoir properties,the Huoshiling Formation of the fissure eruption volcano area has poor conditions of hydrocarbon accumulation.According to the comprehensive analysis of the data of drill-ing,oil testing and earthquake,it could be considered that the central vent eruption volcano in the western studied area is the favorable exploration area of Huoshiling Formation,in which the source rocks are deep and semi-deep lake mudstones,reservoir including pyroclastic rock,conglomerate and volcanic rocks,the reservoir space are mainly fracture and pore.%松辽盆地梨树断陷双龙地区白垩系火石岭组发育中心式和裂隙式两种喷发型火山,其在发育规模、油气成藏等方面存在不同。中心式喷

  3. Constraining the onset of flood volcanism in Isle of Skye Lava Field, British Paleogene Volcanic Province

    Angkasa, Syahreza; Jerram, Dougal. A.; Svensen, Henrik; Millet, John M.; Taylor, Ross; Planke, Sverre


    In order to constrain eruption styles at the onset of flood volcanism, field observations were undertaken on basal sections of the Isle of Skye Lava Field, British Paleogene Volcanic Province. This study investigates three specific sections; Camus Ban, Neist Point and Soay Sound which sample a large area about 1500 km2 and can be used to help explain the variability in palaeo-environments at the onset of flood volcanism. Petrological analysis is coupled with petrophysical lab data and photogrammetry data to create detailed facies models for the different styles of initiating flood basalt volcanism. Photogrammetry is used to create Ortho-rectified 3D models which, along with photomontage images, allow detailed geological observations to be mapped spatially. Petrographic analyses are combined with petrophysical lab data to identify key textural variation, mineral compositions and physical properties of the volcanic rocks emplaced during the initial eruptions. Volcanism initiated with effusive eruptions in either subaerial or subaqueous environments resulting in tuff/hyaloclastite materials or lava flow facies lying directly on the older Mesozoic strata. Volcanic facies indicative of lava-water interactions vary significantly in thickness between different sections suggesting a strong accommodation space control on the style of volcanism. Camus Ban shows hyaloclastite deposits with a thickness of 25m, whereas the Soay Sound area has tuffaceous sediments of under 0.1m in thickness. Subaerial lavas overly these variable deposits in all studied areas. The flood basalt eruptions took place in mixed wet and dry environments with some significant locally developed water bodies (e.g. Camus Ban). More explosive eruptions were promoted in some cases by interaction of lavas with these water bodies and possibly by local interaction with water - saturated sediments. We record key examples of how palaeotopography imparts a primary control on the style of volcanism during the

  4. Determining reserve requirements in DK1 area of Nord Pool using a probabilistic approach

    Saez Gallego, Javier; Morales González, Juan Miguel; Madsen, Henrik


    a probabilistic framework where the reserve requirements are computed based on scenarios of wind power forecast error, load forecast errors and power plant outages. Our approach is first motivated by the increasing wind power penetration in power systems worldwide as well as the current market design of the DK1......Allocation of electricity reserves is the main tool for transmission system operators to guarantee a reliable and safe real-time operation of the power system. Traditionally, a deterministic criterion is used to establish the level of reserve. Alternative criteria are given in this paper by using...... area of Nord Pool, where reserves are scheduled prior to the closure of the day-ahead market. The risk of the solution under the resulting reserve schedule is controlled by two measures: the LOLP (Loss-of-Load Probability) and the CVaR (Conditional Value at Risk). Results show that during the case...

  5. Volcanic signals in oceans

    Stenchikov, Georgiy L.


    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  6. Inexpensive Instrument for In Situ Characterization of Particulate Matter in Volcanic Ash Plumes Project

    National Aeronautics and Space Administration — Volcanic research is a significant part of the "Earth Surface & Interior" focus area of the NASA Earth Science program. After a volcanic eruption, the...

  7. Framework for crisis preparedness planning: Four required areas for developing a learning process.

    Eriksson, Kerstin


    To outline a framework for preparedness planning at the organizational level. The study is based on a content analysis of research literature as well as an analysis of interviews with six preparedness planners working in Swedish local authorities. The study setting included Swedish local authorities of different sizes. The participants are preparedness planners responsible for coordinating crisis management work in Swedish local authorities. The study includes preparedness planners with different backgrounds, education, experiences, and gender. A presentation of 19 factors of preparedness planning identified in the literature and a discussion around how preparedness planners perceive those factors. The main outcome measures are knowledge about how both researcher and practitioner understand and argue around different factors of preparedness planning. The result of this study is a framework for preparedness planning. As preparedness planning ought to be a learning process, the presented framework builds on four areas connected to learning: prerequisites for preparedness planning, who should be involved, what is to be learned, and how should the work be shaped. The analysis of factors identified in the literature and also in the interviews with preparedness planners illustrates that the four areas connected to learning are required for developing a preparedness planning process.

  8. Evidence of Multiple Flank Collapse at Volcan Baru, Panama

    Herrick, J. A.; Rose, W. I.


    Michigan Tech's Peace Corps Master's International program (PCMI) in Geological Hazards has enabled several long-term investigations of active volcanoes in Latin America. To contribute to volcanic hazard assessments in Panama and achieve the goals defined by the PCMI program, we developed this debris avalanche project to address outstanding questions regarding Volcan Baru's most devastating event - massive slope failure of the western flank. Relying on basic mapping tools as well as the 2007 USGS Open-File Report focusing on hazard assessments of Panama's youngest and potentially active volcano, identification of the debris avalanche deposits (DAD) required detailed field investigations to determine the limits of the units. Extending across an area larger than 600 km2, field strategies were developed based on outcrop exposures within drainages and road-cuts. Aerial photos and DEMs of Baru's nested craters were interpreted by earlier scientists as the remains of two collapsed flanks. The results from in-depth field traverses provide several important discoveries: paleosols and sharp contacts within the stratigraphy indicate multiple DAD, deeply weathered hummocks red-flag the deposits more than 50-km away from Baru's crater, and high-quality radiocarbon samples (up to 45-cm long fragments of entrained wood) lie in the distal reaches of the debris flow area. During the 2008-2009 field seasons, we received assistance from the University of Panama, Civil Protection, and Panama's National Institute of Geography. Support from local experts and feedback from professional scientists of the Smithsonian Institution and Costa Rica's Institute of Electricity were invaluable. The 2-year investment in volcanic hazard studies has brought together resources from several countries as well as fresh data that will benefit the residents and emergency management officials of Panama. Jigsaw fractured clasts lie within Volcan Baru's debris avalanche deposits more than 28 km south of the

  9. The α-β phase transition in volcanic cristobalite.

    Damby, D. E.; Llewellin, E.W.; Horwell, C. J.; Williamson, B.J.; Najorka, J; Cressey, G.; Carpenter, M.A.


    Cristobalite is a common mineral in volcanic ash produced from dome-forming eruptions. Assessment of the respiratory hazard posed by volcanic ash requires understanding the nature of the cristobalite it contains. Volcanic cristobalite contains coupled substitutions of Al3+ and Na+ for Si4+; similar co-substitutions in synthetic cristobalite are known to modify the crystal structure, affecting the stability of the α and β forms and the observed transition between them. Here, for the first time...

  10. Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

    Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia


    In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

  11. Characterization of the volcanic and hypabissal rocks of the Paleoproterozoic Iricoumé Group in the Pitinga region and Balbina Lake area, Amazonian Craton, Brazil: Petrographic distinguishing features and emplacement conditions

    Simões, Matheus Silva; Almeida, Marcelo Esteves; de Souza, Antonio Gilmar Honorato; da Silva, Desaix Paulo Balieiro; Rocha, Paloma Gabriela


    The Iricoumé Group (1.897 to 1.875 Ma) is a widespread volcanic sequence in the Amazonian Craton, South American Platform. In the Pitinga region, it consists of acidic to intermediate ignimbrites with cogenetic surge and ash-fall deposits associated to hypabissal and effusive acidic rocks. In the Balbina Lake area it consists of acidic to intermediate effusive rocks, crystal-rich ignimbrites and pumice-rich ignimbrites. Detailed petrographic studies of phenocrysts and crystal fragments provided characterization and distinctive features of pyroclastic, effusive and hypabissal rocks. The phenocrysts of hypabissal rocks were affected by high temperature resorption and flow-related physical fragmentation, the effusive rocks can have a considerable content of crystal fragments due to intense dissolution and fragmentation of the phenocrysts and the pyroclastic rocks crystal fragments are generated mainly by decompression mechanic fragmentation. Dissolution and resorption of quartz and feldspar crystals may have acted at pressure conditions between 500 MPa and 100 MPa, in response to rapid decompression in the magma ascent. The viscosity values of 7,5-10 log η (Pa s) for anhydrous conditions decrease exponentially with estimated water addition. The amount of phenocrysts and their intratelluric character in the volcanic units of Iricoumé Group can be related to a magma chamber with high content of crystals. We suggest that even with the addition of water in the magma, the viscosities had a drastic increase with progressive crystal growth due to the viscosity dependence on the solid fraction and the deposits were generated by the extrusion of viscous lava and pyroclastic flows.

  12. Monitoring Persistent Volcanic Emissions from Sulphur Springs, Saint Lucia: A Community Approach to Disaster Risk Reduction

    Joseph, E. P.; Beckles, D. M.; Cox, L.; Jackson, V. B.; Alexander, D.


    Volcanic and geothermal emissions are known natural sources of volatiles to the atmosphere. Volcanogenic air pollutants known to cause the most serious impact are carbon dioxide (CO2), sulphur dioxide (SO2), hydrogen chloride (HCl) and hydrogen fluoride (HF). Some studies into the potential for volcanic emissions to produce chronic diseases in humans indicate that areas of major concern include respiratory problems, particularly silicosis (Allen et al. 2000; Baxter et al. 1999; Buist et al. 1986), psychological stress (Shore et al. 1986), and chemical impacts of gas or ash (Giammanco et al. 1998). Sulphur Springs Park in Saint Lucia has a very high recreational value with >200,000 visitors annually, while the nearby town of Soufrière has >8,400 residents. Residents and visitors have raised concerns about the volcanic emissions and its health effects. As part of the volcanic surveillance programme undertaken by the UWI, Seismic Research Centre (SRC) in Saint Lucia, a new monitoring network has been established for quantifying the ambient SO2 in air, to which staff and visitors at the volcanic park are exposed to. The implementation and continued operation of this network has involved the training of local personnel in the active field sampling and analytical techniques required for the assessment of ambient SO2 concentrations, using a low cost monitor as well as commercial passive samplers. This approach recognizes that environmental hazards are a usual part of life and productive livelihoods, and to minimize post-disaster response and recovery it is beneficial to promote preparedness and mitigation, which is best achieved at the local level with community involvement. It is also intended that the volcanic emissions monitoring network could be used as a method to establish and maintain community-based initiatives that would also be helpful when volcanic threat manifests.

  13. Volcanic Rocks and Features

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

  14. Global volcanic emissions: budgets, plume chemistry and impacts

    Mather, T. A.


    Over the past few decades our understanding of global volcanic degassing budgets, plume chemistry and the impacts of volcanic emissions on our atmosphere and environment has been revolutionized. Global volcanic emissions budgets are needed if we are to make effective use of regional and global atmospheric models in order to understand the consequences of volcanic degassing on global environmental evolution. Traditionally volcanic SO2 budgets have been the best constrained but recent efforts have seen improvements in the quantification of the budgets of other environmentally important chemical species such as CO2, the halogens (including Br and I) and trace metals (including measurements relevant to trace metal atmospheric lifetimes and bioavailability). Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents and during electrical discharges in ash-rich volcanic plumes. These reactive trace species have important consequences for gas plume chemistry and impacts, for example, in terms of the global fixed nitrogen budget, volcanically induced ozone destruction and particle fluxes to the atmosphere. Volcanically initiated atmospheric chemistry was likely to have been particularly important before biological (and latterly anthropogenic) processes started to dominate many geochemical cycles, with important consequences in terms of the evolution of the nitrogen cycle and the role of particles in modulating the Earth's climate. There are still many challenges and open questions to be addressed in this fascinating area of science.

  15. Volcanic rock properties control sector collapse events

    Hughes, Amy; Kendrick, Jackie; Lavallée, Yan; Hornby, Adrian; Di Toro, Giulio


    Volcanoes constructed by superimposed layers of varying volcanic materials are inherently unstable structures. The heterogeneity of weak and strong layers consisting of ash, tephra and lavas, each with varying coherencies, porosities, crystallinities, glass content and ultimately, strength, can promote volcanic flank and sector collapses. These volcanoes often exist in areas with complex regional tectonics adding to instability caused by heterogeneity, flank overburden, magma movement and emplacement in addition to hydrothermal alteration and anomalous geothermal gradients. Recent studies conducted on the faulting properties of volcanic rocks at variable slip rates show the rate-weakening dependence of the friction coefficients (up to 90% reduction)[1], caused by a wide range of factors such as the generation of gouge and frictional melt lubrication [2]. Experimental data from experiments conducted on volcanic products suggests that frictional melt occurs at slip rates similar to those of plug flow in volcanic conduits [1] and the bases of mass material movements such as debris avalanches from volcanic flanks [3]. In volcanic rock, the generation of frictional heat may prompt the remobilisation of interstitial glass below melting temperatures due to passing of the glass transition temperature at ˜650-750 ˚C [4]. In addition, the crushing of pores in high porosity samples can lead to increased comminution and strain localisation along slip surfaces. Here we present the results of friction tests on both high density, glass rich samples from Santaguito (Guatemala) and synthetic glass samples with varying porosities (0-25%) to better understand frictional properties underlying volcanic collapse events. 1. Kendrick, J.E., et al., Extreme frictional processes in the volcanic conduit of Mount St. Helens (USA) during the 2004-2008 eruption. J. Structural Geology, 2012. 2. Di Toro, G., et al., Fault lubrication during earthquakes. Nature, 2011. 471(7339): p. 494-498. 3

  16. Volcanic Environments Monitoring by Drones Mud Volcano Case Study

    Amici, S.; Turci, M.; Giulietti, F.; Giammanco, S.; Buongiorno, M. F.; La Spina, A.; Spampinato, L.


    Volcanic activity has often affected human life both at large and at small scale. For example, the 2010 Eyjafjallajokull eruption caused severe economic damage at continental scale due to its strong effect on air traffic. At a local scale, ash fall and lava flow emission can cause harm and disruption. Understanding precursory signals to volcanic eruptions is still an open and tricky challenge: seismic tremor and gas emissions, for example, are related to upcoming eruptive activity but the mechanisms are not yet completely understood. Furthermore, information related to gases emission mostly comes from the summit crater area of a volcano, which is usually hard to investigate with required accuracy. Although many regulation problems are still on the discussion table, an increasing interest in the application of cutting-edge technology like unmanned flying systems is growing up. In this sense, INGV (Istituto Nazionale di Geofisica e Vulcanologia) started to investigate the possibility to use unmanned air vehicles for volcanic environment application already in 2004. A flight both in visual- and radio-controlled mode was carried out on Stromboli volcano as feasibility test. In this work we present the preliminary results of a test performed by INGV in collaboration with the University of Bologna (aerospace division) by using a multi-rotor aircraft in a hexacopter configuration. Thermal camera observations and flying tests have been realised over a mud volcano located on its SW flank of Mt. Etna and whose activity proved to be related to early stages of magma accumulation within the volcano.

  17. 火山岩气藏储层岩相特征及其对储层物性的影响——以徐深气田徐东地区白垩系营城组一段火山岩为例%Lithofacies characteristics of volcanic gas reservoirs and their influence on reservoir physical properties: a case study of Member 1 of Cretaceous Yingcheng Formation in Xudong area of the Xushen gas field

    陈欢庆; 胡永乐; 冉启全; 闫林; 孙作兴


    Taking the volcanic reservoir of Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field as an example, the authors studied lithofacies characteristics of the volcanic gas reservoir and their influences on reservoir physical properties with the purpose of effectively forecasting and exploiting the volcanic reservoir.On the basis of identification of volcanic rock types and recognition of volcanic rock bodies by combining geological data with logging data and seismic data, the authors analyzed volcanic lithofacies characteristics and their relationship with reservoir physical properties and forecast the favorable prospecting areas by using data from wells, sections and plane lithofacies.The results indicate that the volcanic reservoir of the Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field was formed by repeated volcanic eruptions, with the lithologies consisting of 10 types.The rhyolite, rhyolite tuff and sedimentary volcanic breccia played the preponderant role.The eruption type in the study area was cranny-center eruption, and crater and volcanic lithofacies were obviously controlled by ruptures.The volcanic bodies were dominated by craters, and different volcanic lithofacies were developed in different positions of volcanic bodies.The volcanic fades inside the volcanic bodies in the study area can be divided into five types and sixteen sub-facies.The results indicate that the volcanic lithology and its combination constitute the basis of the division of volcanic fades, and the spreading of volcanic fades controls the distribution of gas reservoirs.The reservoir development areas include the lower part and upper part and top overflow sub-facies of overflow facies, splash down sub-facies and air falling sub-facies, middle extrusive sub-facies, exterior sub-facies of extrusive facies and volcanic neck sub-facies of volcanic channels facies.The sub-facies of the volcanic reservoir include volcanic sub-lithfacies of volcanic neck

  18. Volcanic geology of Admiralty Bay, King George Island, Antarctica

    邢光福; 王德滋; 金庆民; 沈渭洲; 陶奎元


    At Admiralty Bay of central King George Island, Keller Peninsula, Ullman Spur and Point Hennequin are main Tertiary volcanic terranes. Field investigation and isotopic datings indicate that, there occurred three periods of eruptions ( three volcanic cycles) and accompanying N-toward migration of the volcanic center on Keller Peninsula. After the second period of eruptions, the crater collapsed and a caldera was formed, then later eruptions were limited at the northern end of the peninsula and finally migrated to Ullman Spur. Thus Keller Peninsula is a revived caldera, and its volcanism migrated toward E with time. Point Hennequin volcanism happened more or less simultaneously with the above two areas, but has no clear relation in chemical evolution with them, frequently it belongs to another independent volcanic center.

  19. Report on the water requirements and water use of the Stillwater National Wildlife Refuge and Management Area Nevada

    US Fish and Wildlife Service, Department of the Interior — The objective of this study was to review past use and establish the minimum future water requirements for that portion of the Stillwater NWR and Management Area...

  20. Role of crustal assimilation and basement compositions in the petrogenesis of differentiated intraplate volcanic rocks: a case study from the Siebengebirge Volcanic Field, Germany

    Schneider, K. P.; Kirchenbaur, M.; Fonseca, R. O. C.; Kasper, H. U.; Münker, C.; Froitzheim, N.


    The Siebengebirge Volcanic Field (SVF) in western Germany is part of the Cenozoic Central European Volcanic Province. Amongst these volcanic fields, the relatively small SVF comprises the entire range from silica-undersaturated mafic lavas to both silica-undersaturated and silica-saturated differentiated lavas. Owing to this circumstance, the SVF represents a valuable study area representative of intraplate volcanism in Europe. Compositions of the felsic lavas can shed some new light on differentiation of intraplate magmas and on the extent and composition of potential crustal assimilation processes. In this study, we provide detailed petrographic and geochemical data for various differentiated SVF lavas, including major and trace element concentrations as well as Sr-Nd-Hf-Pb isotope compositions. Samples include tephriphonolites, latites, and trachytes with SiO2 contents ranging between 53 and 66 wt%. If compared to previously published compositions of mafic SVF lavas, relatively unradiogenic 143Nd/144Nd and 176Hf/177Hf coupled with radiogenic 87Sr/86Sr and 207Pb/204Pb lead to the interpretation that the differentiated volcanic rocks have assimilated significant amounts of lower crustal mafic granulites like the ones found as xenoliths in the nearby Eifel volcanic field. These crustal contaminants should possess unradiogenic 143Nd/144Nd and 176Hf/177Hf, radiogenic 87Sr/86Sr, and highly radiogenic 207Pb/204Pb compositions requiring the presence of ancient components in the central European lower crust that are not sampled on the surface. Using energy-constrained assimilation-fractional crystallisation (EC-AFC) model calculations, differentiation of the SVF lithologies can be modelled by approximately 39-47 % fractional crystallisation and 6-15 % crustal assimilation. Notably, the transition from silica-undersaturated to silica-saturated compositions of many felsic lavas in the SVF that is difficult to account for in closed-system models is also well explained by

  1. Experimental studies of anomalous radon activity in the Tlamacas Mountain, Popocatepetl Volcano area, México: new tools to study lithosphere-atmosphere coupling for forecasting volcanic and seismic events

    Jose Antonio Lopez Cruz Abeyro


    Full Text Available

    This study presents and discusses the results of soil radon monitoring at three different volcano sites and one reference site, from December 2007 to January 2009. This relates to the activity of the Popocatepetl Volcano and a radon survey and gamma-ray spectrometry in the area between Paso de Cortes and Tlamacas Mountain, and in the adjacent regions. The results are applied to the aspects of atmosphere electricity and lithosphere-atmosphere coupling in relation to the forecasting of volcano and earthquake activity. The monitoring of radon release reveals a decrease in radon concentration (down to total suppression with approaching moderate volcanic eruptions. The behavior of the radon activity at the Tlamacas site is more apparent, compared to other observational sites. The average level of radon release observed at the Tlamacas site is much higher, with some characteristic variations. Both the radon survey and gamma-ray spectrometry indicate intensive diffusion radon emission localized in the area of Tlamacas Mountain. The average radon concentration in the area of Tlamacas is about 10-20-fold greater than the background volcano values. The new concept of lithosphere-atmosphere coupling is presented: intensive radon release in high elevated areas shortens and modifies the Earth-to-thunderclouds electric circuit, which provokes microdischarges into the air close to the ground, attracting lightning discharges. This concept attempts to explain in a new way the noise-like geomagnetic emissions registered before major earthquakes, and it promotes interest for the study of thunderstorm activity in seismo-active zones, as a promising instrument for earthquake forecasting.


    罗雪; 罗明高; 林军; 袁述武; 乐园; 陈忠云


    Characteristics of lithology,physical and pore structure of the Carboniferous volcanic rocks in the 6th and the 7th districts of Karamay oil field are studied through observation and analysis of drilling cores of 665.56 meters long from 32 drilling wells,470 thin sections,666 physical analysis samples and 82 drilling wells logging data.It is showed that burial depth of layers,lithology and fractures are 3 main factors influencing the reservoirs in this area,and the most favorable reservoir is located in the south of the 6 district and the middle of the 7 district.Pyroclastic rock and sedimentary rock are the main rock types in the area and the major lithology of volcanic rock reservoir is breccias lava and basalt characteristic of low porosity and permeability.Reservoir space is dominated by stoma,intercrystal pore,vug and pre-existing fractures.The favorable reservoir mainly distributes in the south and northwest of 6 district and in the middle of 7 district.%针对32口井665.56 m岩心、470块岩矿薄片、666个物性分析样品以及82口井测井等资料,对克拉玛依油田六七区石炭系火山岩的岩性、物性以及孔隙结构特征进行了研究,结果表明该区影响火山岩储层的主要因素主要有地层埋深、岩性以及裂缝影响,最有利的储集区位于六区南部和七中区.研究区岩石类型主要为火山熔岩类、火山碎屑岩类和沉积岩类,火山岩储层主要岩性为角砾熔岩和玄武岩;孔隙度、渗透率较低;储集空间以气孔、晶间孔、溶蚀孔和原生裂缝为主;有利火山岩储层主要分布于六区南部、西北部以及七中区.

  3. MED SUV TASK 6.3 Capacity building and interaction with decision makers: Improving volcanic risk communication through volcanic hazard tools evaluation, Campi Flegrei Caldera case study (Italy)

    Nave, Rosella; Isaia, Roberto; Sandri, Laura; Cristiani, Chiara


    has been applied also on the scientific output of MED-SUV WP6, as a tool for the short-term probabilistic volcanic hazard assessment. For the Campi Flegrei volcanic system, the expected tool has been implemented to compute hazard curves, hazard maps and probability maps for tephra fallout on a target grid covering the Campania region. This allows the end user to visualize the hazard from tephra fallout and its uncertainty. The response of end-users to such products will help to determine to what extent end-users understand them, find them useful, and match their requirements. In order to involve also Etna area in WP6 TASK 3 activities, a questionnaire developed in the VUELCO project (Volcanic Unrest in Europe and Latin America) has been proposed to Sicily Civil Protection officials having decision-making responsibility in case of volcanic unrest at Etna and Stromboli, to survey their opinions and requirements also in case of volcanic unrest

  4. Factors that influence the membrane area of a multistage microfiltration process required to produce a micellar casein concentrate.

    Hurt, Emily E; Barbano, David M


    The objective of the work reported in this paper was to develop a theoretical model to determine the effect of type of microfiltration (MF)-process feed, number of stages, and flux on the minimization of the MF membrane area required to produce a 95% serum protein-reduced micellar casein concentrate. The MF feed, number of stages, and flux were all factors that had an effect on the MF membrane area and should be taken into consideration when designing a MF system to produce a 95% serum protein-reduced micellar casein concentrate. Feeding the MF process with a diluted ultrafiltration retentate (DUR) diluted to the protein concentration of skim milk, as opposed to skim milk, reduced the required membrane area by 36% for a 5-stage process. When DUR was the MF feed, feed protein concentration, which depended on the number of MF stages, was optimized. The DUR protein concentration that minimized the required MF membrane area was 2.47, 3.85, 4.77, and 5.41% for a 2-, 3-, 4-, or 5-stage MF process, respectively. For a 5-stage process, increasing the protein concentration of the feed from 3.2 to 5.4% decreased the required MF membrane area by 10%. It was also found that as the number of stages increased from 2 to 5, the required MF membrane area decreased by 39%, when the MF feed was DUR at the optimal feed protein concentration. Finally, increasing the flux from 50 to 60 kg/m(2) per hour decreased the required MF membrane area by 17% when the MF feed was DUR at the optimal MF feed protein concentration. Overall, using DUR as a feed for MF could reduce the amount of MF membrane area required to make a 95% serum protein-reduced micellar casein concentrate.

  5. Multiple sets of information synthesized to describe fractures of volcanic reservoir: Taking volcanic reservoir of the Member 1 of Yingcheng Formation in Xudong Area of Xushen Gas Field as an example.%多信息综合火山岩储层裂缝表征:以徐深气田徐东地区营城组一段火山岩储层为例

    陈欢庆; 胡永乐; 靳久强; 冉启全; 王拥军


    从成因角度将徐深气田徐东地区营城组一段火山岩储层裂缝划分为构造裂缝、冷凝收缩裂缝、炸裂缝、溶蚀裂缝、缝合缝、风化裂缝等多种类型.根据动静结合的思路,综合岩心、镜下薄片、常规和FMI测井资料、地震等多信息以及地震相干分析和蚂蚁追踪等技术.对各类型裂缝发育特征进行详细表征.结果表明,上述井震资料的结合可以完成火山岩储层裂缝表征,宏观上沿着徐东地区徐中断裂和徐东断裂裂缝最为发育,大致呈近SN向展布.微观上在发育SN向靠近断裂带裂缝的同时,还发育众多EW向或近EW向的裂缝.对裂缝成因机制分析,研究区目的层火山岩储层裂缝成因影响因素包括构造作用、火山岩性、火山岩体、火山岩相和成岩作用等,其中以构造作用和成岩作用为主.%The volcanic reservoir fractures of the Member 1 of Yingcheng Formation in Xudong Area of Xushen Gas Field are divided according to their origins into tectonic fractures, condensation contracted fractures, exploded fractures, corrosion fractures, stitched fractures and weathering fractures. Synthesizing multiple sets of information from cores, microsections and FMI logging data and using seismic variance and ant tracking technology, we described the characteristics of all kinds of fractures in detail. The results indicated that fractures developed along Xuzhong Faults and Xudong Faults in NS direction in macroscopic view. And many fractures developed along EW direction in microcosmic view at the same time. The analysis of genetic mechanisms of fractures suggested that the fractures of volcanic reservoir of the Member 1 of Yingcheng in Xudong Area of Xushen Gas Field were affected by tectonic processes, volcanic lithology, volcanic bodies, volcanic lithofacies and diagenesis, among which tectonic processes and diagenesis played the leading role.

  6. 78 FR 4788 - Regulated Navigation Area; Reporting Requirements for Barges Loaded With Certain Dangerous...


    ... under section 4(a) of the Administrative Procedure Act (APA) (5 U.S.C. 553(b)). This provision... follows: PART 165--REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS 0 1. The authority citation...

  7. The Geologic Basis for Volcanic Hazard Assessment for the Proposed High-Level Radioactive Waste Repository at Yucca Mountain, Nevada

    F. Perry


    Studies of volcanic risk to the proposed high-level radioactive waste repository at Yucca Mountain have been ongoing for 25 years. These studies are required because three episodes of small-volume, alkalic basaltic volcanism have occurred within 50 km of Yucca Mountain during the Quaternary. Probabilistic hazard estimates for the proposed repository depend on the recurrence rate and spatial distribution of past episodes of volcanism in the region. Several independent research groups have published estimates of the annual probability of a future volcanic disruption of the proposed repository, most of which fall in the range of 10{sup -7} to 10{sup -9} per year; similar conclusions were reached. through an extensive expert elicitation sponsored by the Department of Energy in 1995-1996. The estimated probability values are dominated by a regional recurrence rate of 10{sup -5} to 10{sup -6} volcanic events per year (equating to recurrence intervals of several hundred thousand years). The recurrence rate, as well as the spatial density of volcanoes, is low compared to most other basaltic volcanic fields in the western United States, factors that may be related to both the tectonic history of the region and a lithospheric mantle source that is relatively cold and not prone to melting. The link between volcanism and tectonism in the Yucca Mountain region is not well understood beyond a general association between volcanism and regional extension, although areas of locally high extension within the region may control the location of some volcanoes. Recently, new geologic data or hypotheses have emerged that could potentially increase past estimates of the recurrence rate, and thus the probability of repository disruption. These are (1) hypothesized episodes of anomalously high strain rate, (2) hypothesized presence of a regional mantle hotspot, and (3) new aeromagnetic data suggesting as many as twelve previously unrecognized volcanoes buried in alluvial-filled basins near

  8. Volcanic hazards to airports

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.


    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  9. Gravimetric control of active volcanic processes

    Saltogianni, Vasso; Stiros, Stathis


    Volcanic activity includes phases of magma chamber inflation and deflation, produced by movement of magma and/or hydrothermal processes. Such effects usually leave their imprint as deformation of the ground surfaces which can be recorded by GNSS and other methods, on one hand, and on the other hand they can be modeled as elastic deformation processes, with deformation produced by volcanic masses of finite dimensions such as spheres, ellipsoids and parallelograms. Such volumes are modeled on the basis of inversion (non-linear, numerical solution) of systems of equations relating the unknown dimensions and location of magma sources with observations, currently mostly GNSS and INSAR data. Inversion techniques depend on the misfit between model predictions and observations, but because systems of equations are highly non-linear, and because adopted models for the geometry of magma sources is simple, non-unique solutions can be derived, constrained by local extrema. Assessment of derived magma models can be provided by independent observations and models, such as micro-seismicity distribution and changes in geophysical parameters. In the simplest case magmatic intrusions can be modeled as spheres with diameters of at least a few tens of meters at a depth of a few kilometers; hence they are expected to have a gravimetric signature in permanent recording stations on the ground surface, while larger intrusions may also have an imprint in sensors in orbit around the earth or along precisely defined air paths. Identification of such gravimetric signals and separation of the "true" signal from the measurement and ambient noise requires fine forward modeling of the wider areas based on realistic simulation of the ambient gravimetric field, and then modeling of its possible distortion because of magmatic anomalies. Such results are useful to remove ambiguities in inverse modeling of ground deformation, and also to detect magmatic anomalies offshore.

  10. Surface ocean iron fertilization: The role of airborne volcanic ash and iron-flux into the Pacific Ocean

    Olgun, N.; Duggen, S.; Croot, P.; Dietze, H.


    Iron is a limiting micro-nutrient for marine primary production (MPP) in vast areas in the surface ocean. Hence, atmospheric supply of iron to the surface ocean can affect marine biogeochemical cycles, associated ocean-atmosphere exchange of CO2 and eventually climate development. Airborne volcanic ash from volcanic eruptions can be an important atmospheric iron-source in the surface ocean by releasing bio-available iron while settling through in the surface ocean. Here we present new data from time-dependent geochemical experiments with pristine (unhydrated) volcanic ash samples and natural seawater by means of Cathodic Stripping Voltammetry. Our results demonstrate that volcanic ash mobilizes significant amounts of soluble Fe within 60 minutes of contact with natural seawater. Depending on the amount of volcanic ash deposited offshore during major volcanic eruptions and the amount of iron that ash can release on contact with seawater, the calculated increase in the surface ocean Fe levels range from several nanomolar up to several hundred nanomolar (nM). Only 2 nM increase in iron concentrations can stimulate massive diatom blooms in the oceanic regions in which MPP is limited by the availability of iron (the iron-limited oceanic areas) (Wells, 2003). Therefore volcanic ash should be able to significantly affect marine phytoplankton growth in an ash fall area, acting as an iron fertilizer. Based on our new iron-release data and marine sediment core data we provide the first estimate of the flux of Fe from volcanic ash into the Pacific Ocean that covers more than 60 percent of the iron-limited oceanic regions. Our calculations show that the flux of Fe from volcanic ash is comparable to the order of magnitude of the flux of Fe from aeolian dust. Our study shows that volcanic ash is a major and so far underestimated atmospheric iron-source for the oceans and therefore an important component in marine biogeochemical iron cycles. Wells, M.L.: The level of iron

  11. 24 CFR 599.105 - Economic condition requirements for a nominated area.


    ... incidence of AIDS, abandoned housing, deteriorated infrastructure, school dropouts, teen pregnancy... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Economic condition requirements for... Requirements for Nomination of Renewal Communities § 599.105 Economic condition requirements for a nominated...

  12. Conception of a method for the creation of volcanic risk index maps

    Bion, P.; Van Wyk de Vries, B.; Valentine, G.


    Risk index maps are a variant of risk maps, having the advantage of containing unique kinds of information - levels of risk spatially represented - and can therefore be a more effective communication tool than traditional risk maps. Nevertheless, despite their apparent simplicity, their achievement is the result of a complex risk analysis, requiring the consideration of multidisciplinary indicators, expressing different parameters of the physical and human dimensions of the environment and their interactions. The risk index is obtained in three main stages: the definition of hazard and vulnerability indicators, the transformation of the indicators into subindices through mathematical processes (formulation, standardization, weighting), and the combination of the subindices into a final index. As of now, only few attempts of risk quantification have been done, related to landslide, flood or seismic hazards, and those linked to volcanic hazards are very incomplete because of the specificities and complexities of these kinds of events and their effects. Volcanic hazards have the particularity of being of different types, moreover all events can combine together or be combined with other external events (e.g. meteorological), and they can reach and therefore affect extensive areas by different phenomena. The methodology developed here assesses risk levels in regions potentially impacted by volcanic hazards. It incorporates volcanic hazard specificities and nuances of "vulnerability" by integrating the diversity of the environmental components. It analyses the natural and human strengths, weaknesses, opportunities and threats, which are located within the areas potentially "at risk". Consequently, it considers negative but also positive indicators (respectively aggravating and improving the potential consequences), which can be internal but also external to the volcanic hazards. The approach also considers a temporal variability of the events and their direct or

  13. Payenia volcanic province, southern Mendoza, Argentina

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge


    The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...

  14. Cretaceous Volcanic Events in Southeastern Jilin Province, China: Evidence from Single Zircon U-Pb Ages

    CHEN Yuejun; SUN Chunlin; SUN Yuewu; SUN Wei


    Mesozoic volcanic rocks in southeastern Jilin Province are an important component of the huge Mesozoic volcanic belt in the northeastern area. Study of the age of their formation is of great significance to recognize Mesozoic volcanic rule in northeastern China. Along with the research of rare Mesozoic biota and extensive Mesozoic mineralization in western Liaoning, a number of researchers have focused on Mesozoic volcanic events. The authors studied the ages of the Cretaceous volcanic rocks in southeastern Jilin Province using single Zircon U-Pb. The result shows that the Sankeyushu Formation volcanic rocks in the Tonghua area are 119.2 Ma in age, the Yingcheng Formation in the Jiutai area 113.4±3.1 Ma, the Jinjiatun Formation in Pinggang Town of Liaoyuan City and the Wufeng volcanic rocks in the Yanji area 103.2±4.7 Ma and 103.6±1 Ma, respectively. Combined with the data of recent publication on volcanic rocks ages; the Cretaceous volcanic events in southeastern Jilin Province can be tentatively subdivided into three eruption periods: 119 Ma, 113 Ma and 103 Ma. The result not only provides important chronology data for subdividing Mesozoic strata in southeastern Jilin Province, establishing Mesozoic volcanic event sequence, discussing geological tectonic background, and surveying the relation between noble metals to the Cretaceous volcanic rocks, but also otters important information of Mesozoic volcanism in northeastern China.

  15. U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: constraints on the age of volcanism and metamorphism

    Christopher L. Kirkland


    Full Text Available Zircons from a felsic volcanic rock in the Toija Formation and a synvolcanic gabbro intrusion in the Salittu Formation within the Orijärvi area were dated by U-Th-Pb SIMS in order to provide depositional constraints on these formations. Zircon crystals from the felsic rock preserve a two-stage crystallisation history with zoned core domains and homogeneous rim domains. Inner domains yield a 1878±4 Ma concordia age, interpreted to determine the crystallisation of this rock. Rims yield a 1815±3 Ma concordia age interpretedto determine the regional metamorphism. Small rounded zircon grains from the Salittu gabbro, located within the Jyly shear zone, yield a concordia age of 1792±5 Ma. We interpret the grain textures to suggest that they recrystallised from inherited zircon seeds during the heat and fluid flow into the shear zone. Although no direct ages for the Salittu Formation have been recovered, field relationships imply that it was deposited between 1878−1875 Ma.

  16. Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

    Hill, David P.; Mangan, Margaret T.; McNutt, Stephen R.


    The onset of volcanic unrest in Long Valley Caldera, California, in 1980 and the subsequent fluctuations in unrest levels through May 2016 illustrate: (1) the evolving relations between scientists monitoring the unrest and studying the underlying tectonic/magmatic processes and their implications for geologic hazards, and (2) the challenges in communicating the significance of the hazards to the public and civil authorities in a mountain resort setting. Circumstances special to this case include (1) the sensitivity of an isolated resort area to media hype of potential high-impact volcanic and earthquake hazards and its impact on potential recreational visitors and the local economy, (2) a small permanent population (~8000), which facilitates face-to-face communication between scientists monitoring the hazard, civil authorities, and the public, and (3) the relatively frequent turnover of people in positions of civil authority, which requires a continuing education effort on the nature of caldera unrest and related hazards. Because of delays associated with communication protocols between the State and Federal governments during the onset of unrest, local civil authorities and the public first learned that the U.S. Geological Survey was about to release a notice of potential volcanic hazards associated with earthquake activity and 25-cm uplift of the resurgent dome in the center of the caldera through an article in the Los Angeles Times published in May 1982. The immediate reaction was outrage and denial. Gradual acceptance that the hazard was real required over a decade of frequent meetings between scientists and civil authorities together with public presentations underscored by frequently felt earthquakes and the onset of magmatic CO2 emissions in 1990 following a 11-month long earthquake swarm beneath Mammoth Mountain on the southwest rim of the caldera. Four fatalities, one on 24 May 1998 and three on 6 April 2006, underscored the hazard posed by the CO2

  17. Distinguishing contributions to diffuse CO2 emissions in volcanic areas from magmatic degassing and thermal decarbonation using soil gas 222Rn-δ13C systematics: Application to Santorini volcano, Greece

    Parks, Michelle M.; Caliro, Stefano; Chiodini, Giovanni; Pyle, David M.; Mather, Tamsin A.; Berlo, Kim; Edmonds, Marie; Biggs, Juliet; Nomikou, Paraskevi; Raptakis, Costas


    potential to quantify magmatic and crustal contributions to the diffuse outgassing of CO2 in volcanic areas, especially those where breakdown of crustal limestone is likely to contribute significantly to the CO2 flux.

  18. Applications of dip angle and coherence attributes to recognition of volcanic edifice in Songliao Basin


    On the basis of the shape and inner structure of volcanic edifice, the dip angle and coherence were selected to recognize the buried volcanic edifices in Songliao Basin. Five volcanic edifices were recognized in both two methods in the first volcanic cycle of Yingcheng Formation and the prediction perfectly corresponds to the drilling results in well XS8 area. The results are satisfying when the prediction method were employed in the exploration and development of Qingshen gas field.

  19. Precambrian Lunar Volcanic Protolife

    Jack Green


    Full Text Available Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.

  20. Volcanic Pipe of the Namuaiv Mountain

    Vladimir K. Karzhavin


    Full Text Available This research was aimed at reconstructing thermodynamic conditions required for the studied mineral assemblages to be created and exist in nature. The results of the investigations confirm to the recent ideas about an important, even leading, role of temperature, pressure and dioxide carbon in diamond formation in volcanic pipers. The results of this theoretical research allows assuming that one of the reasons for the absence of diamonds in the Namuaiv Mountain volcanic pipe may lie in the increased content of water and oxidizing environmental conditions of their formation

  1. Abstract on the Effective validation of both new and existing methods for the observation and forecasting of volcanic emissions

    Sathnur, Ashwini


    Validation of the Existing products of the Remote Sensing instruments Review Comment Number 1 Ground - based instruments and space - based instruments are available for remote sensing of the Volcanic eruptions. Review Comment Number 2 The sunlight spectrum appears over the volcanic geographic area. This sunlight is reflected with the image of the volcano geographic area, to the satellite. The satellite captures this emitted spectrum of the image and further calculates the occurrences of the volcanic eruption. Review Comment Number 3 This computation system derives the presence and detection of sulphur dioxide and Volcanic Ash in the emitted spectrum. The temperature of the volcanic region is also measured. If these inputs derive the possibility of occurrence of an eruption, then the data is manually captured by the system for further usage and hazard mitigation. Review Comment Number 4 The instrument is particularly important in capturing the volcanogenic signal. This capturing operation should be carried out during the appropriate time of the day. This is carried out ideally at the time of the day when the reflected image spectra is best available. Capturing the data is not advisable to be performed at the night time, as the sunlight spectra is at its minimum. This would lead to erroneous data interpretation, as there is no sunlight for reflection of the volcanic region. Thus leading to the least capture of the emitted light spectra. Review Comment Number 5 An ideal area coverage of the spectrometer is mandatory. This is basically for the purpose of capturing the right area of data, in order to precisely derive the occurrence of a volcanic eruption. The larger the spatial resolution, there would be a higher capture of the geographic region, and this would lead to a lesser precise data capture. This would lead to missing details in the data capture. Review Comment Number 6 Ideal qualities for the remote sensing instrument are mentioned below:- Minimum "false

  2. Tephra layers from Holocene lake sediments of the Sulmona Basin, central Italy: implications for volcanic activity in Peninsular Italy and tephrostratigraphy in the central Mediterranean area

    Giaccio, B.; Messina, P.; Sposato, A.; Voltaggio, M.; Zanchetta, G.; Galadini, F.; Gori, S.; Santacroce, R.


    "Pomici di Avellino" eruptions. Alternatively, since at present there is no evidence of a similar significant activity in the proximal area of this well-known volcano, a hitherto unknown origin of these tephras cannot be role out. The results of the present study provide new data that enrich our previous knowledge of the Holocene tephrostratigraphy and tephrochronology in central Italy, and a new model for the recent explosive activity of the Peninsular Italy volcanoes and the dispersal of the related pyroclastic deposits.

  3. Real time retrieval of volcanic cloud particles and SO2 by satellite using an improved simplified approach

    Pugnaghi, Sergio; Guerrieri, Lorenzo; Corradini, Stefano; Merucci, Luca


    Volcanic plume removal (VPR) is a procedure developed to retrieve the ash optical depth, effective radius and mass, and sulfur dioxide mass contained in a volcanic cloud from the thermal radiance at 8.7, 11, and 12 µm. It is based on an estimation of a virtual image representing what the sensor would have seen in a multispectral thermal image if the volcanic cloud were not present. Ash and sulfur dioxide were retrieved by the first version of the VPR using a very simple atmospheric model that ignored the layer above the volcanic cloud. This new version takes into account the layer of atmosphere above the cloud as well as thermal radiance scattering along the line of sight of the sensor. In addition to improved results, the new version also offers an easier and faster preliminary preparation and includes other types of volcanic particles (andesite, obsidian, pumice, ice crystals, and water droplets). As in the previous version, a set of parameters regarding the volcanic area, particle types, and sensor is required to run the procedure. However, in the new version, only the mean plume temperature is required as input data. In this work, a set of parameters to compute the volcanic cloud transmittance in the three quoted bands, for all the aforementioned particles, for both Mt. Etna (Italy) and Eyjafjallajökull (Iceland) volcanoes, and for the Terra and Aqua MODIS instruments is presented. Three types of tests are carried out to verify the results of the improved VPR. The first uses all the radiative transfer simulations performed to estimate the above mentioned parameters. The second one makes use of two synthetic images, one for Mt. Etna and one for Eyjafjallajökull volcanoes. The third one compares VPR and Look-Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull volcano acquired by MODIS aboard the Aqua satellite on 11 May 2010 at 14:05 GMT.

  4. Role of volcanism in climate and evolution

    Axelrod, D.I.


    Several major episodes of Tertiary explosive volcanism coincided with sharply lowered temperature as inferred from oxygen-isotope composition of foraminiferal tests in deep-sea cores. At these times, fossil floras in the western interior recorded significant changes. Reductions in taxa that required warmth occurred early in the Paleogene. Later, taxa that demand ample summer rain were reduced during a progressive change reflecting growth of the subtropic high. Other ecosystem changes that appear to have responded to volcanically induced climatic modifications include tachytely in Equidae (12 to 10 m.y. B.P.), rapid evolution of grasses (7 to 5 m.y. B.P.), evolution of marine mammals, and plankton flucuations. Although Lake Cretaceous extinctions commenced as epeiric seas retreated, the pulses of sharply lowered temperature induced by explosive volcanism, together with widespread falls of volcanic ash, may have led to extinction of dinosaurs, ammonites, cycadeoids, and other Cretaceous taxa. earlier, as Pangaea was assembled, Permian extinctions resulted not only from the elimination of oceans, epeiric seas, and shorelines, and the spread of more-continental climates, bu also from the climatic effects of major pulses of global volcanism and Gondwana glaciation.

  5. Lung problems and volcanic smog

    ... releases gases into the atmosphere. Volcanic smog can irritate the lungs and make existing lung problems worse. ... deep into the lungs. Breathing in volcanic smog irritates the lungs and mucus membranes. It can affect ...

  6. Thermal vesiculation during volcanic eruptions

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo


    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  7. Volcanism and Oil & Gas In Northeast China

    Shan Xuanlong


    Based on study on the relation with volcanic rock and oil & gas in Songliao Basin and Liaohe Basin in northeast China, author proposes that material from deep by volcanism enrichs the resources in basins, that heat by volcanism promotes organic matter transforming to oil and gas, that volcanic reservoir is fracture, vesicular, solution pore, intercrystal pore.Lava facies and pyroclastic facies are favourable reservoir. Mesozoic volcanic reservoir is majority of intermediate, acid rock,but Cenozoic volcanic reservoir is majority of basalt. Types of oil and gas pool relating to volcanic rock include volcanic fracture pool, volcanic unconformity pool, volcanic rock - screened pool, volcanic darpe structural pool.

  8. Tropical Volcanic Soils From Flores Island, Indonesia



    Full Text Available Soils that are developed intropical region with volcanic parent materials have many unique properties, and high potential for agricultural use.The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia,and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed fromandesitic volcanic materials from Flores Island were studied to determine their properties. They were compared intheir physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristicdifferent. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes withdifferent annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed differentproperties compared to the soils derived from volcanic tuff, even though they were developed from the sameintermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences.The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, andvery friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cationexchange capacity (CEC. The soils in western region have higher clay content and showing more developed than ofthe eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order.The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherablemineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soilswere classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands

  9. The trace-element characteristics of Aegean and Aeolian volcanic arc marine tephra

    Clift, Peter; Blusztajn, Jerzy


    High-silica volcanic ashes are found within deep-sea sediments throughout the Eastern Mediterranean. Although coring by Ocean Drilling Program has penetrated Lower Pliocene (˜4 Ma) sediments, few ashes older than 400 k.y. have been recovered, suggesting a young initiation to subaerial Aegean Arc volcanism. Ashes derived from the Aegean volcanic front were cored south and east of the arc, and are typified by medium-K, calc-alkaline major-element compositions, contrasting with high-K ashes from the Aeolian Arc found in the Ionian Sea and as far east as Crete. Ion microprobe analysis of individual glass shards shows that all the ashes have a light rare earth element (LREE)-enriched pattern after normalizing against a chondrite standard. Aeolian Arc-derived ashes show greater enrichment than those from the Aegean area. Within the latter set, two groups are discernible, a mildly enriched set similar to the volcanoes of the arc volcanic front, and a more enriched group corresponding to lavas from the backarc region or possible from western Anatolia. Multi-element `spider diagrams' also show a bimodal division of enriched and depleted Aegean ashes, possibly caused by source depletion due to melt extraction in the Aegean backarc followed by remelting under the volcanic front. Relative Nb depletion, a characteristic of arc volcanism, is seen to be modest in Aegean and non-existent in Aeolian ashes. Using B/Be as a proxy for the flux of material from the subducting slab, this influence is seen to be low in the Aeolian Arc but higher than at Vesuvius. B/Be is higher again in the Aegean Arc. These differences may reflect the rate of subduction in each system. Data suggest caution is required when correlating ashes solely on the basis of major elements, as alkaline ashes from the central part of the study may be derived from Italy or from the Aegean backarc.

  10. The Dilemmas of Risk-Sensitive Development on a Small Volcanic Island

    Emily Wilkinson


    Full Text Available In the Small Islands Developing State (SIDS of St Vincent and the Grenadines in the Caribbean, the most destructive disasters in terms of human casualties have been the multiple eruptions of La Soufrière volcano situated in the north of St Vincent. Despite this major threat, people continue to live close to the volcano and national development plans do not include risk reduction measures for volcanic hazards. This paper examines the development options in volcanic SIDS and presents a number of conundrums for disaster risk management on the island of St Vincent. Improvements in monitoring of volcanic hazards and ongoing programmes to enhance communications systems and encourage community preparedness planning have increased awareness of the risks associated with volcanic hazards, yet this has not translated into more risk-informed development planning decisions. The current physical development plan in fact promotes investment in infrastructure in settlements located within the zone designated very high-hazard. However, this is not an anomaly or an irrational decision: severe space constraints in SIDS, as well as other historical social and economic factors, limit growth and options for low-risk development. Greater attention needs to be placed on developing measures to reduce risk, particularly from low-intensity hazards like ash, limiting where possible exposure to volcanic hazards and building the resilience of communities living in high-risk areas. This requires planning for both short- and longer-term impacts from renewed activity. Volcanic SIDS face multiple hazards because of their geography and topography, so development plans should identify these interconnected risks and options for their reduction, alongside measures aimed at improving personal preparedness plans so communities can learn to live with risk.

  11. Application of spatial methods to identify areas with lime requirement in eastern Croatia

    Bogunović, Igor; Kisic, Ivica; Mesic, Milan; Zgorelec, Zeljka; Percin, Aleksandra; Pereira, Paulo


    With more than 50% of acid soils in all agricultural land in Croatia, soil acidity is recognized as a big problem. Low soil pH leads to a series of negative phenomena in plant production and therefore as a compulsory measure for reclamation of acid soils is liming, recommended on the base of soil analysis. The need for liming is often erroneously determined only on the basis of the soil pH, because the determination of cation exchange capacity, the hydrolytic acidity and base saturation is a major cost to producers. Therefore, in Croatia, as well as some other countries, the amount of liming material needed to ameliorate acid soils is calculated by considering their hydrolytic acidity. For this research, several interpolation methods were tested to identify the best spatial predictor of hidrolitic acidity. The purpose of this study was to: test several interpolation methods to identify the best spatial predictor of hidrolitic acidity; and to determine the possibility of using multivariate geostatistics in order to reduce the number of needed samples for determination the hydrolytic acidity, all with an aim that the accuracy of the spatial distribution of liming requirement is not significantly reduced. Soil pH (in KCl) and hydrolytic acidity (Y1) is determined in the 1004 samples (from 0-30 cm) randomized collected in agricultural fields near Orahovica in eastern Croatia. This study tested 14 univariate interpolation models (part of ArcGIS software package) in order to provide most accurate spatial map of hydrolytic acidity on a base of: all samples (Y1 100%), and the datasets with 15% (Y1 85%), 30% (Y1 70%) and 50% fewer samples (Y1 50%). Parallel to univariate interpolation methods, the precision of the spatial distribution of the Y1 was tested by the co-kriging method with exchangeable acidity (pH in KCl) as a covariate. The soils at studied area had an average pH (KCl) 4,81, while the average Y1 10,52 cmol+ kg-1. These data suggest that liming is necessary

  12. March 10, 2006, Transportation Conformity Rule That Addresses Requirements for Project-level Conformity Determinations in PM2.5 and PM10 Nonattainment and Maintenance Areas

    This final rule, published March 10, 2006, establishes requirements for project-level conformity determinations in particulate matter (PM) 2.5 nonattainment and maintenance areas, and revises existing requirements for projects in PM10 areas.

  13. Radon levels in the volcanic region of La Garrotxa, Spain

    Baixeras, C. [Grup de Fisica de les Radiacions. Edifici Cc, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)]. E-mail:; Bach, J. [Unitat de Geodinamica Externa. Departament de Geologia. Edifici Cs, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Amgarou, K. [Grup de Fisica de les Radiacions. Edifici Cc, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Moreno, V. [Grup de Fisica de les Radiacions. Edifici Cc, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Font, Ll. [Grup de Fisica de les Radiacions. Edifici Cc, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)


    A preliminary survey in the city of Olot, the main town of the volcanic region of La Garrotxa, showed that dwellings built on volcanic formations present higher indoor radon levels than dwellings on non-volcanic materials. The soil of the area is not especially rich in radium. However, some of the volcanic materials present very high permeability and therefore radon entering the houses might have travelled over long distances. In this paper we present indoor radon values measured in a larger survey carried out during April-July 2004. The influence of the volcanic materials found in the preliminary survey has been confirmed. The results obtained suggest the possibility that radon comes from the degassification of mantle through active faults. The values obtained in working places do not constitute a relevant radiological risk for workers.

  14. Geochemical constraints on the relationship between the Miocene-Pliocene volcanism and tectonics in the Palaoco and Fortunoso volcanic fields, Mendoza Region, Argentina: New insights from 40Ar/39Ar dating, Sr-Nd-Pb isotopes and trace elements

    Dyhr, Charlotte T.; Holm, Paul M.; Llambías, Eduardo J.


    New 40Ar/39Ar analyses constrain the formation of the volcanic succession of Sierra de Palaoco in the present back-arc of the Andean Southern Volcanic Zone (SVZ), near 36°S, to the Late Miocene and assigns them to the Huincán II Formation. The composition of major and trace elements, Sr, Nd and Pb isotopes of the Palaoco and nearby Río Grande rocks require a strong arc-like component in the mantle that is absent or weak in both Early Miocene (Fortunoso Group) and Pleistocene alkaline lavas (Llancanelo Group) erupted in the same area. We evaluate the relative roles of varying mantle source compositions and crustal contamination in the generation of geochemically very different lavas from the Palaoco, Fortunoso and Río Grande volcanic fields, north of the Payún Matrú Volcano. The source for the Early Miocene Fortunoso(I) basalts was a OIB-type mantle devoid of subduction zone input. This type of OIB-like volcanic activity terminated due to a change from an extensional to a compressional tectonic regime. Towards the end of the Miocene renewed alkaline volcanism at Fortunoso (II) display a transition to arc-type incompatible element enrichment. Shortly after the calc-alkaline Palaoco volcanism started with a very strong geochemical arc-signature including Ba/La ≈ 60 and La/Nb = 2-3. After a quiesence of 1 Ma the major part of the voluminous Late Palaoco basalts were erupted around 7.5 Ma over a few hundred ka. These are less enriched in Ba and Sr and have compositions like many Holocene rocks of the Southern Volcanic Zone. Isotopically the Fortunoso I and Palaoco rocks are distinct. Regional volcanism of the Charilehue, Huincán I and II mostly has a moderate arc-type enrichment indicating incipient arc developments. However, Palaoco and La Brea at (c. 35°S) show full geochemical arc-signature, and we infer that a frontal arc was established. The subsequent development in the Palaoco-Río Grande area encompasses renewed late Pliocene calc-alkaline low volume



    This paper is concentrated on Cenozoic volcanism and geothermal resources in Northeast China. There are a lot of Cenozoic volcanoes, a large area of volcanic rocks, a large number of active faults and rich geothermal resources in Northeast China. The time and space characteristics of Cenozoic volcanism and the space distribution characters of hot springs and high geothermal flux regions in Northeast China are described and discussed on the basis of geological, geothermal, drilling and volcanological data. It is revealed that the hot springs and high geothermal flux regions are re lated to the Cenozoic volcanism, rifting and faulting in Northeast China. It is especially emphasized that the hot springs and high geothermal anomaly areas are controlled by active deep faults. It is proposed that the Cenozoic volcanism re gions, rift basins, active fault belts, activated plate suture zones and large earthquake occurrence points are the best areas for prospecting geothermal resources. The geothermal resources in younger volcanic zones are richer than those in older volcanic belts. The hot springs and active or activated faults might be a very good clue for looking for geothermal resources.

  16. 9 CFR 72.11 - Quarantined area; cattle considered infested; requirements for placing in noninfectious pens or...


    ... TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS TEXAS (SPLENETIC) FEVER IN CATTLE § 72.11... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Quarantined area; cattle considered infested; requirements for placing in noninfectious pens or premises. 72.11 Section 72.11 Animals...

  17. Geomagnetic imprint of the Persani volcanism

    Besutiu, Lucian; Seghedi, Ioan; Zlagnean, Luminita; Atanasiu, Ligia; Popa, Razvan-Gabriel; Pomeran, Mihai; Visan, Madalina


    The Persani small volume volcanism is located in the SE corner of the Transylvanian Depression, at the north-western edge of the intra-mountainous Brasov basin. It represents the south-easternmost segment of the Neogene-Quaternary volcanic chain of the East Carpathians. The alkaline basalt monogenetic volcanic field is partly coeval with the high-K calc-alkaline magmatism south of Harghita Mountains (1-1.6 Ma). Its eruptions post-dated the calc-alkaline volcanism in the Harghita Mountains (5.3-1.6 Ma), but pre-dated the high-K calc-alkaline emissions of Ciomadul volcano (1.0-0.03 Ma). The major volcanic forms have been mapped in previous geological surveys. Still, due to the small size of the volcanoes and large extent of tephra deposits and recent sediments, the location of some vents or other volcanic structures has been incompletely revealed. To overcome this problem, the area was subject to several near-surface geophysical investigations, including paleomagnetic research. However, due to their large-scale features, the previous geophysical surveys proved to be an inappropriate approach to the volcanological issues. Therefore, during the summers of 2014 and 2015, based on the high magnetic contrast between the volcanic rocks and the hosting sedimentary formations, a detailed ground geomagnetic survey has been designed and conducted, within central Persani volcanism area, in order to outline the presence of volcanic structures hidden beneath the overlying deposits. Additionally, information on the rock magnetic properties was also targeted by sampling and analysing several outcrops in the area. Based on the acquired data, a detailed total intensity scalar geomagnetic anomaly map was constructed by using the recent IGRF12 model. The revealed pattern of the geomagnetic field proved to be fully consistent with the direction of magnetisation previously determined on rock samples. In order to enhance the signal/noise ratio, the results were further processed by

  18. United States-Chile binational exchange for volcanic risk reduction, 2015—Activities and benefits

    Pierson, Thomas C.; Mangan, Margaret T.; Lara Pulgar, Luis E.; Ramos Amigo, Álvaro


    In 2015, representatives from the United States and Chile exchanged visits to discuss and share their expertise and experiences dealing with volcano hazards. Communities in both countries are at risk from various volcano hazards. Risks to lives and property posed by these hazards are a function not only of the type and size of future eruptions but also of distances from volcanoes, structural integrity of volcanic edifices, landscape changes imposed by recent past eruptions, exposure of people and resources to harm, and any mitigative measures taken (or not taken) to reduce risk. Thus, effective risk-reduction efforts require the knowledge and consideration of many factors, and firsthand experience with past volcano crises provides a tremendous advantage for this work. However, most scientists monitoring volcanoes and most officials delegated with the responsibility for emergency response and management in volcanic areas have little or no firsthand experience with eruptions or volcano hazards. The reality is that eruptions are infrequent in most regions, and individual volcanoes may have dormant periods lasting hundreds to thousands of years. Knowledge may be lacking about how to best plan for and manage future volcanic crises, and much can be learned from the sharing of insights and experiences among counterpart specialists who have had direct, recent, or different experiences in dealing with restless volcanoes and threatened populations. The sharing of information and best practices can help all volcano scientists and officials to better prepare for future eruptions or noneruptive volcano hazards, such as large volcanic mudflows (lahars), which could affect their communities.

  19. Water in volcanic glass: From volcanic degassing to secondary hydration

    Seligman, Angela N.; Bindeman, Ilya N.; Watkins, James M.; Ross, Abigail M.


    have more bubbles per unit area (25-77 mm-2) than felsic tephra (736 mm-2) and thicker average bubble walls (0.07 mm) than felsic tephra (0.02 mm). We use a simplified diffusion model to quantify the hydration rate of vesicular glass as a function of the diffusivity of water and the average bubble wall thickness. Based on fits to our hydration rate data, we estimate the initial low-temperature diffusivity at 0.1 wt.% H2Ot in volcanic glass (mafic and felsic) to be on the order of 10-3 to 10-4 μm2/year and find that differences in hydration rates between mafic and felsic tephra can be attributed primarily to differences in vesicularity, although slightly slower hydration of basalt cannot be precluded. We also observe no consistent temporal difference in secondary meteoric water uptake in wet versus dry and hot versus cold climates.

  20. Exploring Hawaiian Volcanism

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken


    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai`i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO's founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists' understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  1. Exploring Hawaiian volcanism

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken


    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai‘i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO’s founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists’ understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  2. The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

    Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.


    over 60 volcanoes, with an average of 10 volcanoes discussed each week. Notable volcanic activity during November 2000-November 2001 included an eruption beginning on 6 February at Nyamuragira in the Democratic Republic of the Congo; it issued low-viscosity lava flows that traveled towards inhabited towns, and also produced ash clouds that adversely effected the health of residents and livestock near the volcano. Eruptions at Mayon in the Philippines on 24 June and 25 July caused local authorities to raise the alert to the highest level, close area airports, and evacuate thousands of residents near the volcano. Most recently a large flank eruption at Etna in Italy began on 17 July and gained worldwide attention as extensive lava flows threatened a small town and a tourist complex. While the information found in the Weekly Volcanic Activity Report, ranging from large eruptions to small precursory events, is of interest to the general public, it has also proven to be a valuable resource to volcano observatory staff, universities, researchers, secondary schools, and the aviation community.

  3. Estimating building exposure and impact to volcanic hazards in Icod de los Vinos, Tenerife (Canary Islands)

    Marti, J.; Spence, R.; Calogero, E.; Ordoñez, A.; Felpeto, A.; Baxter, P.


    Principal and subsidiary building structure characteristics and their distribution have been inventoried in Icod, Tenerife (Canary Islands) and used to evaluate the vulnerability of individual buildings to three volcanic hazards: tephra fallout, volcanogenic earthquakes and pyroclastic flows. The procedures described in this paper represent a methodological framework for a comprehensive survey of all the buildings at risk in the area around the Teide volcano in Tenerife. Such a methodology would need to be implemented for the completion of a comprehensive risk assessment for the populations under threat of explosive eruptions in this area. The information presented in the paper is a sample of the necessary data required for the impact estimation and risk assessment exercises that would need to be carried out by emergency managers, local authorities and those responsible for recovery and repair in the event of a volcanic eruption. The data shows there are micro variations in building stock characteristics that would influence the likely impact of an eruption in the area. As an example of the use of this methodology for vulnerability assessment, we have applied a deterministic simulation model of a volcanic eruption from Teide volcano and its associated ash fallout which, when combined with the vulnerability data collected, allows us to obtain the vulnerability map of the studied area. This map is obtained by performing spatial analysis with a Geographical Information System (GIS). This vulnerability analysis is included in the framework of an automatic information system specifically developed for hazard assessment and risk management on Tenerife, but which can be also applied to other volcanic areas. The work presented is part of the EU-funded EXPLORIS project (Explosive Eruption Risk and Decision Support for EU Populations Threatened by Volcanoes, EVR1-2001-00047).

  4. Geochemistry and Tectonic Setting of Late Triassic Volcanic Rocks in Reshui Area,Qinghai%青海热水地区晚三叠世火山岩地球化学特征及构造环境

    李运冬; 刘小玉


    青海热水地区位于秦祁昆三大造山带的结合部位,该区发育晚三叠世鄂拉山组火山岩。岩石类型以英安岩及英安质火山碎屑岩为主,其次为中性的安山质火山岩和酸性的流纹质火山岩,为一套高 K、低 Ti、准铝质的钙碱性系列火山岩。SiO2含量为59.62%~76.46%,总碱含量 ALK 为6.59%~8.04%,ANK 在1.14~1.80,里特曼系数σ在1.72~2.41,岩石矿物结晶分离程度高,但固结程度一般。稀土总量 REE在126.76×10-6~240.07×10-6,LREE/HREE均值为10.19,属轻稀土富集型,且轻稀土富集程度高于重稀土富集程度,δEu 值多在0.37~0.56亏损较为明显,稀土元素标准化配分曲线均呈右倾较缓的平滑曲线。大离子半径亲石元素 Rb、Ba、U、K、Th较为富集,高场强元素 Nb、Ta、Ti、P等较为亏损,原始地幔标准化配分曲线呈明显左高右低的“W”型,具有明显的弧火山岩特点。Mg#大部分在16~36,206 Pb/204 Pb=18.181~18.218,207 Pb/204 Pb=15.570~15.588,208 Pb/204 Pb=38.368~38.529,显示岩浆来源于下地壳。该区火山岩与 A型俯冲构造活动有关,利用 Hf/3-Th-Nb/16等构造环境判别图解分析,其形成于陆缘弧环境。%Reshui area is located in the binding site of Qinling,Qilianshan and Kunlunshan orogenic belt, and the late Triassic volcanic rock developed in the area is part of Elashan formation.As a set of volcano rocks with high K content,low Ti content and metaluminous calc-alkaline characteristics,the late Triassic rock are mainly consisted of dacite and dacitic pyroclastic rock,followed by neutral andesitic volcano rock and acidic rhyolitic volcano rock.The content of SiO2 is between 59.62% and 76.46%,the content of ALK ranges from 6.59% to 8.04%,the content of ANK is from 1.14 to 1.80,and the value of Rittmann coefficient varies between 1.72 and 2.41,the degree of rock mineral fractionation crystallization is high,but the degree of consolidation is common.The total of REE is between 126.76

  5. Subdiffusion of volcanic earthquakes

    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...

  6. MODIS volcanic ash retrievals vs FALL3D transport model: a quantitative comparison

    Corradini, S.; Merucci, L.; Folch, A.


    Satellite retrievals and transport models represents the key tools to monitor the volcanic clouds evolution. Because of the harming effects of fine ash particles on aircrafts, the real-time tracking and forecasting of volcanic clouds is key for aviation safety. Together with the security reasons also the economical consequences of a disruption of airports must be taken into account. The airport closures due to the recent Icelandic Eyjafjöll eruption caused millions of passengers to be stranded not only in Europe, but across the world. IATA (the International Air Transport Association) estimates that the worldwide airline industry has lost a total of about 2.5 billion of Euro during the disruption. Both security and economical issues require reliable and robust ash cloud retrievals and trajectory forecasting. The intercomparison between remote sensing and modeling is required to assure precise and reliable volcanic ash products. In this work we perform a quantitative comparison between Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of volcanic ash cloud mass and Aerosol Optical Depth (AOD) with the FALL3D ash dispersal model. MODIS, aboard the NASA-Terra and NASA-Aqua polar satellites, is a multispectral instrument with 36 spectral bands operating in the VIS-TIR spectral range and spatial resolution varying between 250 and 1000 m at nadir. The MODIS channels centered around 11 and 12 micron have been used for the ash retrievals through the Brightness Temperature Difference algorithm and MODTRAN simulations. FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic particles that outputs, among other variables, cloud column mass and AOD. Three MODIS images collected the October 28, 29 and 30 on Mt. Etna volcano during the 2002 eruption have been considered as test cases. The results show a general good agreement between the retrieved and the modeled volcanic clouds in the first 300 km from the vents. Even if the

  7. Aurorae and Volcanic Eruptions


    bears witness to the important role of the zonal winds in the Jovian atmosphere (blowing along the same latitude) in transporting the haze material, much stronger than that of the meridional winds (along the same longitude), even at the high latitudes of the auroral region. Jupiter's rapid rotation (about 10 hours per revolution) obviously plays an important role in this. A volcanic eruption on Io ESO PR Photo 21f/01 ESO PR Photo 21f/01 [Preview - JPEG: 400 x 322 pix - 50k] [Normal - JPEG: 800 x 643 pix - 160k] Caption : ESO PR Photo 21f/01 shows a small area of an image obtained through a narrow-band filter centered at 4.07 µm. The bright object is the Jovian moon Io ; its image is further enlarged to the left. A strong asymmetry is evident, with the Tvashtar hot spot well visible in the upper right quadrant. Io , the innermost major satellite of Jupiter is one of the most remarkable bodies in the solar system. Volcanic activity on its surface was first discovered by the NASA Voyager 1 and 2 spacecraft during fly-by's in 1979. This is attributed to internal heating caused by tidal effects between Jupiter, Io and the other Galilean satellites. Apart from the Earth, Io is the only other body in the solar system that is currently volcanically active. The volcanism on this moon is the main source of electrically charged particles (plasma) in the magnetosphere of Jupiter. A bright polar feature is visible on several ISAAC images of Io , obtained through a narrow-band filter at 4.07 µm, cf. PR Photo 21f/01 . In this waveband, the effect of reflected sunlight is negligible and the image resolution is the best. Applying a basic filtering algorithm, the sharpness of this image was further enhanced. The recorded emission is found to correspond to the Tvashtar hot spot that was discovered by NASA Infrared Telescope Facility (IRTF) in November 1999 and observed simultaneously by the Galileo spacecraft during its I25 flyby. Such outbursts normally have a short lifetime, less than

  8. Developing International Guidelines on Volcanic Hazard Assessments for Nuclear Facilities

    Connor, Charles


    Worldwide, tremendous progress has been made in recent decades in forecasting volcanic events, such as episodes of volcanic unrest, eruptions, and the potential impacts of eruptions. Generally these forecasts are divided into two categories. Short-term forecasts are prepared in response to unrest at volcanoes, rely on geophysical monitoring and related observations, and have the goal of forecasting events on timescales of hours to weeks to provide time for evacuation of people, shutdown of facilities, and implementation of related safety measures. Long-term forecasts are prepared to better understand the potential impacts of volcanism in the future and to plan for potential volcanic activity. Long-term forecasts are particularly useful to better understand and communicate the potential consequences of volcanic events for populated areas around volcanoes and for siting critical infrastructure, such as nuclear facilities. Recent work by an international team, through the auspices of the International Atomic Energy Agency, has focused on developing guidelines for long-term volcanic hazard assessments. These guidelines have now been implemented for hazard assessment for nuclear facilities in nations including Indonesia, the Philippines, Armenia, Chile, and the United States. One any time scale, all volcanic hazard assessments rely on a geologically reasonable conceptual model of volcanism. Such conceptual models are usually built upon years or decades of geological studies of specific volcanic systems, analogous systems, and development of a process-level understanding of volcanic activity. Conceptual models are used to bound potential rates of volcanic activity, potential magnitudes of eruptions, and to understand temporal and spatial trends in volcanic activity. It is these conceptual models that provide essential justification for assumptions made in statistical model development and the application of numerical models to generate quantitative forecasts. It is a

  9. Hurricane Sandy puts NJ hospital under extreme stress, highlighting vulnerabilities, areas requiring improvement.


    When monster storm, Hurricane Sandy, struck the northeastern coast in late October, the emergency systems for many hospitals in the region were stressed beyond their limits. At least four hospitals in the region had to be evacuated, and many hospitals lost power and access to essential services. Using backup generators, CentraState Medical Center in Freehold, NJ, was able to keep its doors open throughout the emergency, but the event highlighted a number of vulnerabilities that administrators will work to improve. Demand for care spiked because people in the hospital's service area could not get in to see their primary care providers. The hospital established care areas next to its emergency department to handle the demand, and it also enabled physicians in the region to see patients in offices on an ambulatory campus, adjacent to the hospital. Emergency department visits increased by about 41% during the hurricane week, admits went up by about 50%, and the number patients sent to observation went up by 450%, according to hospital administrators. In the future, hospital leaders say practice drills need to regularly test for events that cause many systems to go down, rather then testing for one vulnerability at a time.

  10. Where can pixel counting area estimates meet user-defined accuracy requirements?

    Waldner, François; Defourny, Pierre


    Pixel counting is probably the most popular way to estimate class areas from satellite-derived maps. It involves determining the number of pixels allocated to a specific thematic class and multiplying it by the pixel area. In the presence of asymmetric classification errors, the pixel counting estimator is biased. The overarching objective of this article is to define the applicability conditions of pixel counting so that the estimates are below a user-defined accuracy target. By reasoning in terms of landscape fragmentation and spatial resolution, the proposed framework decouples the resolution bias and the classifier bias from the overall classification bias. The consequence is that prior to any classification, part of the tolerated bias is already committed due to the choice of the spatial resolution of the imagery. How much classification bias is affordable depends on the joint interaction of spatial resolution and fragmentation. The method was implemented over South Africa for cropland mapping, demonstrating its operational applicability. Particular attention was paid to modeling a realistic sensor's spatial response by explicitly accounting for the effect of its point spread function. The diagnostic capabilities offered by this framework have multiple potential domains of application such as guiding users in their choice of imagery and providing guidelines for space agencies to elaborate the design specifications of future instruments.

  11. Volcanic ash as fertiliser for the surface ocean

    B. Langmann


    Full Text Available Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time establishes a causal connection between oceanic iron-fertilisation and volcanic ash supply.

  12. Volcanic ash as fertiliser for the surface ocean

    B. Langmann


    Full Text Available Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time strongly suggests a connection between oceanic iron-fertilisation and volcanic ash supply.

  13. Geologic Map of Lassen Volcanic National Park and Vicinity, California

    Clynne, Michael A.; Muffler, L.J. Patrick


    The geologic map of Lassen Volcanic National Park (LVNP) and vicinity encompasses 1,905 km2 at the south end of the Cascade Range in Shasta, Lassen, Tehama, and Plumas Counties, northeastern California (fig. 1, sheet 3). The park includes 430 km2 of scenic volcanic features, glacially sculpted terrain, and the most spectacular array of thermal features in the Cascade Range. Interest in preserving the scenic wonders of the Lassen area as a national park arose in the early 1900s to protect it from commercial development and led to the establishment in 1907 of two small national monuments centered on Lassen Peak and Cinder Cone. The eruptions of Lassen Peak in 1914-15 were the first in the Cascade Range since widespread settling of the West in the late 1800s. Through the printed media, the eruptions aroused considerable public interest and inspired renewed efforts, which had languished since 1907, to establish a national park. In 1916, Lassen Volcanic National Park was established by combining the areas of the previously established national monuments and adjacent lands. The southernmost Cascade Range is bounded on the west by the Sacramento Valley and the Klamath Mountains, on the south by the Sierra Nevada, and on the east by the Basin and Range geologic provinces. Most of the map area is underlain by middle to late Pleistocene volcanic rocks; Holocene, early Pleistocene, and late Pliocene volcanic rocks (radiometric dating, photographs of geologic features, and links to related data or web sites. Data contained in the CD-ROM are also available on this Web site. The southernmost Cascade Range consists of a regional platform of basalt and basaltic andesite, with subordinate andesite and sparse dacite. Nested within these regional rocks are 'volcanic centers', defined as large, long-lived, composite, calc-alkaline edifices erupting the full range of compositions from basalt to rhyolite, but dominated by andesite and dacite. Volcanic centers are produced by the

  14. Evolving protected-area impacts in Panama: impact shifts show that plans require anticipation

    Haruna, Akiko; Pfaff, Alexander; van den Ende, Sander; Joppa, Lucas


    Protected areas (PAs) are the leading forest conservation policy, so accurate evaluation of future PA impact is critical in conservation planning. Yet by necessity impact evaluations use past data. Here we argue that forward-looking plans should blend such evaluations with anticipation of shifts in threats. Applying improved methods to evaluate past impact, we provide rigorous support for that conceptual approach by showing that PAs’ impacts on deforestation shifted with land use. We study the Republic of Panama, where species-dense tropical forest faces real pressure. Facing variation in deforestation pressure, the PAs’ impacts varied across space and time. Thus, if shifts in pressure levels and patterns could be anticipated, that could raise impact.

  15. Requirement of a Ship Breaking Yard at the Arvand Free Zone Area

    Homayoun Yousefi


    Full Text Available In this paper, the author is going to investigate the concept of ship recycling which implies to the materials and equipment including end of ships life. The scraped steel is melted down and is commonly used in the construction industries of ship recycling countries, and some equipment might be re-used in other industries too. A segment of this paper is dedicated to describe about the strategic position of Arvand River and the location of Arvand Free Zone area at the Persian Gulf. It should be noted that ship recycling commonly takes place in developing countries which tend to have a competitive advantage due to the low cost labor, may have weaker environmental protection / worker health and safety regulations, and have national demand for the outputs of the activity. The International Maritime Organization (IMO adopted the Hong Kong International Convention related to the safety and environmental sound recycling of ships to address the growing about the environment, job health and safety risks related to ship recycling. A part of this paper dedicated to review the role of the Hong Kong Convention in order to ensure the process of ship recycling without risks to human health and to the environment. The main part of this paper is designated to evaluate the role of establishment of a ship scraping yard at the Arvand Free Zone Area, its market at the Persian Gulf and improving the safety of navigation at the Arvand River. The research methodology of this paper will be designated to consider the qualitative part of this research by using interview with the experts in order to find out and select the key factors for further consideration; as a result of that a model will be created which can be tested by a questioner. In addition to the above explanation, relationship between the variables and testing hypothesizes of this research will be analyzed by using SPSS and Lisrel software as quantitative part of this research.

  16. Space and time variability of heating requirements for greenhouse tomato production in the Euro-Mediterranean area.

    Mariani, Luigi; Cola, Gabriele; Bulgari, Roberta; Ferrante, Antonio; Martinetti, Livia


    The Euro-Mediterranean area is the seat of a relevant greenhouse activity, meeting the needs of important markets. A quantitative assessment of greenhouse energy consumption and of its variability in space and time is an important decision support tool for both greenhouse-sector policies and farmers. A mathematical model of greenhouse energy balance was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for vegetables growing. Tomato was adopted as reference crop, due to its high energy requirement for fruit setting and ripening and its economic relevance. In order to gain a proper description of the Euro-Mediterranean area, 56 greenhouse areas located within the ranges 28°N-72°N and 11°W-55°E were analyzed over the period 1973-2014. Moreover, the two 1973-1987 and 1988-2014 sub-periods were separately studied to describe climate change effects on energy consumption. Results account for the spatial variability of energy needs for tomato growing, highlighting the strong influence of latitude on the magnitude of heat requirements. The comparison between the two selected sub-periods shows a decrease of energy demand in the current warm phase, more relevant for high latitudes. Finally, suggestions to reduce energy consumptions are provided.

  17. Are protected areas required to maintain functional diversity in human-modified landscapes?

    H Eden W Cottee-Jones

    Full Text Available The conversion of forest to agriculture across the world's tropics, and the limited space for protected areas, has increased the need to identify effective conservation strategies in human-modified landscapes. Isolated trees are believed to conserve elements of ecological structure, providing micro-sites for conservation in matrix landscapes, and facilitating seed dispersal and forest restoration. Here we investigate the role of isolated Ficus trees, which are of critical importance to tropical forest ecosystems, in conserving frugivore composition and function in a human-modified landscape in Assam, India. We surveyed the frugivorous birds feeding at 122 isolated Ficus trees, 33 fruit trees, and 31 other large trees across a range of 32 km from the nearest intact forest. We found that Ficus trees attracted richer and more abundant assemblages of frugivores than the other tree categories. However, incidence function estimates revealed that forest specialist species decreased dramatically within the first kilometre of the forest edge. Despite this, species richness and functional diversity remained consistent across the human-modified landscape, as habitat generalists replaced forest-dependent frugivores, and accounted for most of the ecological function found in Ficus trees near the forest edge. We recommend that isolated Ficus trees are awarded greater conservation status, and suggest that their conservation can support ecologically functional networks of frugivorous bird communities.

  18. Volcanism on Mars. Chapter 41

    Zimbelman, J. R.; Garry, W. B.; Bleacher, J. E.; Crown, D. A.


    Spacecraft exploration has revealed abundant evidence that Mars possesses some of the most dramatic volcanic landforms found anywhere within the solar system. How did a planet half the size of Earth produce volcanoes like Olympus Mons, which is several times the size of the largest volcanoes on Earth? This question is an example of the kinds of issues currently being investigated as part of the space-age scientific endeavor called "comparative planetology." This chapter summarizes the basic information currently known about volcanism on Mars. The volcanoes on Mars appear to be broadly similar in overall morphology (although, often quite different in scale) to volcanic features on Earth, which suggests that Martian eruptive processes are not significantly different from the volcanic styles and processes on Earth. Martian volcanoes are found on terrains of different age, and Martian volcanic rocks are estimated to comprise more than 50% of the Martian surface. This is in contrast to volcanism on smaller bodies such as Earth's Moon, where volcanic activity was mainly confined to the first half of lunar history (see "Volcanism on the Moon"). Comparative planetology supports the concept that volcanism is the primary mechanism for a planetary body to get rid of its internal heat; smaller bodies tend to lose their internal heat more rapidly than larger bodies (although, Jupiter's moon Io appears to contradict this trend; Io's intense volcanic activity is powered by unique gravitational tidal forces within the Jovian system; see "Volcanism on Io"), so that volcanic activity on Mars would be expected to differ considerably from that found on Earth and the Moon.

  19. Nature and origin of secondary mineral coatings on volcanic rocks of the Black Mountain, Stonewall Mountain, and Kane Springs Wash volcanic centers, southern, Nevada

    Taranik, James V.; Hsu, Liang C.; Spatz, David M.; Chenevey, Michael J.


    The following subject areas are covered: (1) genetic, spectral, and LANDSAT Thematic Mapper imagery relationship between desert varnish and tertiary volcanic host rocks, southern Nevada; (2) reconnaissance geologic mapping of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada, using multispectral thermal infrared imagery; (3) interregional comparisons of desert varnish; and (4) airborne scanner (GERIS) imagery of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada.

  20. Volcanic Ash Nephelometer Probe Project

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes may enable unprecedented observations of...

  1. Individual variation changes dispersal distance and area requirements of a checkerspot butterfly.

    Brown, Leone M; Crone, Elizabeth E


    Individual variation in movement can have important consequences for spatial population dynamics. For instance, individual variation increases leptokurtosis in dispersal distance, such that more individuals move very short and very long distances relative to a homogeneous population. We quantified individual variation in movement of the Baltimore checkerspot butterfly (Euphydryas phaeton) to investigate its importance for two conservation-related metrics: the expected dispersal distance and the critical minimum patch size, or the smallest area within which a population can persist based on loss due to emigration. All movement parameters showed among-individual variation, with the greatest variation in move lengths and time spent resting. Correlations in among-individual movement parameters indicated that some butterflies were generally more mobile than others. We incorporated empirically estimated movement and demographic parameters into two individual-based models (IBMs), one with homogeneity in movement among individuals, and one with heterogeneity in movement. As expected, individual variation in movement increased the leptokurtosis of lifetime movement distance; the maximum difference in distance moved was substantial (-850 m vs. -5800 m) and is likely of significance for conservation. Individual variation also affected the critical minimum patch size, but the difference (-0.7 ha vs. -0.5 ha) is unlikely to be ecologically significant. Notably, populations with individual variation had higher growth rates in small patches and lower growth rates in large patches, a logical consequence of increased leptokurtosis. Individual variation in movement is fairly straightforward to quantify using mixed effects models and is important for spatial population dynamics, thus we encourage its inclusion in studies of other systems.

  2. Submarine Volcanic Morphology of Santorini Caldera, Greece

    Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.


    Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at

  3. Volcanic Eruptions and Climate

    Robock, A.


    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  4. 汝阳地区熊耳群火山岩内夹层硅质岩的微区特征及地质意义%Micro-Area Characteristics of Laminated Chert in the Volcanic Rocks of Xionger Group of Ruyang Area and Its Geological Significances

    罗安; 李红中; 赵明臻; 杨志军; 梁锦; 何俊国


    The Xionger Group was originated from the volcanic eruption and sedimentation in Precambrian ,whose sedimentary strata at the top were named Majiahe Formation .In the Majiahe Formation ,there were hydrothermal chert widely distributed , which were exhibited to be interlayers in the volcanic rocks .The polarized microscope ,X-ray diffraction (XRD) ,Raman and electron back scatter diffraction (EBSD) were conducted to study the characteristics in micro area of the jasperite samples ,which were from the sedimentary interlayers in the volcanic rocks of Majiahe Formation in Xionger Group .As shown in the micropho-tographs and EBSD images ,the quartz in the chert had small grain size ,low degree of crystallinity and close packed structure , which quite agreed with the characteristics of hydrothermal sedimentary chert .In the chert of Xionger Group ,there were clear banded (or lamellar) structures which were contributed by the diversities of the grain size and mineral composition .The different bands (or lamellars) had alternative appearance repeatedly ,and denoted the diversities and periodic changes in the substance sup-ply during the precipitation .According to the results of the XRD analysis ,the majority minerals of the chert was low tempera-ture quartz ,whose lattice parameters were a= b=0.491 3 nm ,c=0.540 5 nm and Z=3 .As denoted in the EBSD image and re-sult of Raman analysis ,several impurity minerals were formed in the chert in different stages ,whose geneses and formation time were quite different .The clay minerals and pyrite were scattered in distribution ,and should be contributed by the original sedi-mentation .On contrary ,the felsic minerals and mafic silicate minerals were originated from the sedimentation of tuffaceous sub-stance during the volcanic eruption .The minerals of volcanic genesis had relatively larger grain size ,and they deposited together with the hydrothermal sediments to form the bands (or lamellars) of coarse minerals .However ,the

  5. System of Volcanic activity



    Full Text Available A comparison is made among the systems of B. G.
    Escher (3, of R. W. van Bemmelen (1 and that of the author (4. In this
    connection, on the basis of Esclier's classification, the terms of "constructiv
    e " and "destructive" eruptions are introduced into the author's system and
    at the same time Escher's concept on the possible relation between the depth
    of magma-chamber and the measure of the gas-pressure is discussed briefly.
    Three complementary remarks to the first paper (4 011 the subject of system
    of volcanic activity are added.

  6. The Zuni-Bandera Volcanic Field, NM: An Analog for Exploring Planetary Volcanic Terrains

    Bleacher, J. E.; Garry, W. B.; Zimbelman, J. R.; Crumpler, L. S.; Aubele, J. C.


    of several overlapping flows in a limited area and also shows the challenge of exploring expansive (100-1000’s square kilometers) volcanic terrains on other planets. The Zuni-Bandera field represents one style of geologic processes (volcanic field development) and in essence is an “end-member” of volcanic field analogs. Results from these studies must be considered with comparable results from other geologic terrains to better represent the complexities of exploring other planetary surfaces.

  7. Halogen Chemistry in Volcanic Plumes (Invited)

    Roberts, Tjarda


    only partially constrained by available observations. Reactions on aerosol are a key driver of the chemistry and are affected by uncertainties in both the HOBr reactive uptake coefficient and the aerosol surface area. Recent work has explored the reactive uptake of HOBr on sulfate-rich aerosol, whilst field-measurements at Mt Etna have aimed to quantify the size-resolved primary aerosol emission, towards improving model representations of this highly non-linear volcanic plume halogen chemistry.

  8. Estimating the frequency of volcanic ash clouds over northern Europe

    Watson, E. J.; Swindles, G. T.; Savov, I. P.; Lawson, I. T.; Connor, C. B.; Wilson, J. A.


    Fine ash produced during explosive volcanic eruptions can be dispersed over a vast area, where it poses a threat to aviation, human health and infrastructure. Here, we focus on northern Europe, which lies in the principal transport direction for volcanic ash from Iceland, one of the most active volcanic regions in the world. We interrogate existing and newly produced geological and written records of past ash fallout over northern Europe in the last 1000 years and estimate the mean return (repose) interval of a volcanic ash cloud over the region to be 44 ± 7 years. We compare tephra records from mainland northern Europe, Great Britain, Ireland and the Faroe Islands, with records of proximal Icelandic volcanism and suggest that an Icelandic eruption with a Volcanic Explosivity Index rating (VEI) ≥ 4 and a silicic magma composition presents the greatest risk of producing volcanic ash that can reach northern Europe. None of the ash clouds in the European record which have a known source eruption are linked to a source eruption with VEI < 4. Our results suggest that ash clouds are more common over northern Europe than previously proposed and indicate the continued threat of ash deposition across northern Europe from eruptions of both Icelandic and North American volcanoes.

  9. Taos Plateau Volcanic Project: A Vehicle for Integration of Concepts in Igneous Petrology

    Henry, D.; Dutrow, B.


    Integrating concepts of igneous petrology is generally a challenge, but can be effective in the context of a project based on actual field, geochemical and geochronological data. The final lab project in the igneous portion of petrology involves a series of volcanic and associated rock samples that were collected from the Taos Plateau Volcanic Field, New Mexico, USA. Samples were collected over an area of several tens of km2 throughout the Plateau and represent a spatially and temporally correlated rock suite related to continental rifting. Rift-related magmatism encompasses much of the diversity of terrestrial magma types. Compositions of mafic magmas range from tholeiite to some of the most silica-undersaturated magmas found on the continents. Large effusive eruptions from fissures are typical of some rifts, whereas others may be dominated by central vent cones or even silicic caldera complexes. The injection of mantle-derived magma in extending crust may have a profound effect on the rheology of the crust and, therefore, the style of deformation associated with extension. Most of these aspects of rift volcanism and a wide range of mafic to silicic magma compositions are represented in the Rio Grande rift and the volcanic rocks of the Taos Plateau. In addition, much published data exists for whole rock and trace element geochemistry as well as geochronology. Rock samples and associated information are presented so that the student must integrate multiple lines of evidence, petrographic, petrologic, geochemical and geochronological data in a geospatial framework, to establish a geologic history of the region. The student must also draw on skills learned in mineralogy and structural geology furthering core geoscience education. Subsequent to the petrology course, the students visit the Taos Plateau Volcanic Field during their required field camp, thus reinforcing the linkage between the classroom setting and geologic reality.

  10. Slab Detachment, Flat Subduction and Slab Rollback in Central Mexico: Fitting the Neogene Evolution of the Trans-Mexican Volcanic Belt into the History and Dynamics of Subduction

    Ferrari, L.


    I present a comparative analysis of the volcanic record of the Trans-Mexican Volcanic Belt (TMVB) and the plate tectonic history since 16 Ma in central Mexico that has important implications for the dynamic of the Cocos-Rivera subduction system. The TMVB volcanism has occurred in episodes characterized by across-arc and along strike variation and/or migration. In its first stage (16 to 10 Ma) the TMVB consisted of a broad andesitic arc emplaced between Long. 102° and 97° 30' (central Mexico). During this period volcanism was absent in the western and eastern TMVB. Between 11 and 6 Ma a voluminous mafic volcanism was emplaced to the northof the previous arc with ages progressively younger from west (Tepic-Guadalajara) to east (Queretaro-Hidalgo). Large calderas and silicic dome complexes developed in latest Miocene and early Pliocene (7.5 to 3.5 Ma) west of the Taxco-San Miguel de Allende fault system (TSMA). East of the TSMA a volcanic gap is clearly observed between ~9 and 3.5 Ma. In the western TMVB small amount of lavas with an intra-plate affinity started to be emplaced since 5 Ma. At the same time the volcanic front migrated to the south by about 70 km. East of the TSMA volcanism resumed at about 3.5 Ma in the Mexico City region and at the end of Pliocene in the eastern TMVB (excluding the Palma Sola area). In the Toluca - Mexico City area the volcanic front migrated trenchward in the Quaternary. No southward migration of the volcanic front is observed in the eastern TMVB. The Middle Miocene volcanism represent a "normal" volcanic arc developed after a gap of ~15 Ma following the formation of the Acapulco trench. I propose that the following unusual volcanic evolution was controlled by the detachment of the deeper part of the Cocos slab and the resulting variation in slab inclination. Slab must have detached after 12.5 following the end of subduction off Baja California. This is a kinematic-dynamic requirement, also supported by the fact that the present

  11. Volcan Reventador's Unusual Umbrella

    Chakraborty, P.; Gioia, G.; Kieffer, S. W.


    In the past two decades, field observations of the deposits of volcanoes have been supplemented by systemmatic, and sometimes, opportunistic photographic documentation. Two photographs of the umbrella of the December 3, 2002 eruption of Volcan Reventador, Ecuador, reveal a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. The material in the umbrella was being swept off a descending pyroclastic flow, and was, therefore, a co-ignimbrite cloud. We propose that the scallops are the result of a turbulent Rayleigh-Taylor (RT) instability with no precedents in volcanology. We ascribe the rare loss of buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. On the basis of the observed wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella of 4000 ~m2/s. This value is consistent with a previously obtained lower bound (200 ~m2/s, K. Wohletz, priv. comm., 2005). We do not know the fate of the material in the umbrella subsequent to the photos. The analysis suggests that the umbrella was negatively buoyant. Field work on the co-ignimbrite deposits might reveal whether or not the material reimpacted, and if so, where and whether or not this material was involved in the hazardous flows that affected the main oil pipeline across Ecuador.

  12. Uranium series, volcanic rocks

    Vazquez, Jorge A.


    Application of U-series dating to volcanic rocks provides unique and valuable information about the absolute timing of crystallization and differentiation of magmas prior to eruption. The 238U–230Th and 230Th-226Ra methods are the most commonly employed for dating the crystallization of mafic to silicic magmas that erupt at volcanoes. Dates derived from the U–Th and Ra–Th methods reflect crystallization because diffusion of these elements at magmatic temperatures is sluggish (Cherniak 2010) and diffusive re-equilibration is insignificant over the timescales (less than or equal to 10^5 years) typically associated with pre-eruptive storage of nearly all magma compositions (Cooper and Reid 2008). Other dating methods based on elements that diffuse rapidly at magmatic temperatures, such as the 40Ar/39Ar and (U–Th)/He methods, yield dates for the cooling of magma at the time of eruption. Disequilibrium of some short-lived daughters of the uranium series such as 210Po may be fractionated by saturation of a volatile phase and can be employed to date magmatic gas loss that is synchronous with volcanic eruption (e.g., Rubin et al. 1994).

  13. Volcanic Eruptions and Climate

    LeGrande, Allegra N.; Anchukaitis, Kevin J.


    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  14. Cluster Analysis of vents in monogenetic volcanic fields, Lunar Crater Volcanic Field (Nevada)

    Tadini, A.; Cortes, J. A.; Valentine, G. A.; Johnson, P. J.; Tibaldi, A.; Bonali, F. L.


    Monogenetic volcanic fields pose a serious risk to human activities and settlements due to their high occurrence around the world and because of the type of eruptive activity that they exhibit. The need of adequate tools to better undertake volcanic hazard assessment for volcanic fields, especially from a spatial point of view, is of key importance at the time of mitigate such hazard. Among these tools, a better understanding of the spatial distribution of cones and vents and any structural/tectonical relationship are essential to understand the plumbing system of the field and thus help to predict the likelihood location of future eruptions. In this study we have developed a spatial methodology, which is the combination of various methodologies developed for volcanic textures and other clustering goals [1,2], to study the clustering of volcanic vents and their relation with structural features from satellite images. The methodology first involves the statistical identification and removal of spatial outliers using a predictive elliptical area [2] and the generation of randomly distributed points in the same predictive area. A comparison of the Near Neighbor Distance (NND) between the generated data and the data measured in a volcanic field is used to determine whether the vents are clustered or not. If the vents are clustered, a combination of hierarchical clustering and K-means [3] is then used to identify the clusters and their related vents. Results are then further constrained with the study of lineaments and other structural features that can be affected and related with the clusters. The methodology was tested in the Lunar Crater Volcanic Field, Nevada (USA) and successfully has helped to identify tectonically controlled lineaments from those that are resultant of geomorphological processes such the drainage control imposed by the cone clusters. Theoretical approaches has been developed before to constrain the plumbing of a volcanic field [4], however these

  15. Geothermal systems in volcanic arcs: Volcanic characteristics and surface manifestations as indicators of geothermal potential and favorability worldwide

    Stelling, P.; Shevenell, L.; Hinz, N.; Coolbaugh, M.; Melosh, G.; Cumming, W.


    This paper brings a global perspective to volcanic arc geothermal assessments by evaluating trends and correlations of volcanic characteristic and surface manifestation data from world power production sites in subduction zone volcanic settings. The focus of the work was to evaluate volcanic centers individually and as a group in these arcs by correlating various geologic characteristics with known potential to host electricity grade geothermal systems at the volcanic centers. A database was developed that describes key geologic factors expected to be indicative of productive geothermal systems in a global training set, which includes all 74 subduction zone volcanic centers world-wide with current or proven power production capability. Importantly, this data set only contains data from subduction zone volcanoes and contains no negative cases, limiting the populations of any statistical groups. Regardless, this is the most robust geothermal benchmark training set for magmatic-heated systems to date that has been made public. The work reported here is part of a larger project that included data collection, evaluation, correlations and weightings, fairway and favorability modeling and mapping, prediction of blind systems, and uncertainty analysis to estimate errors associated with model predictions. This first paper describes volcano characteristics, compositions and eruption ages and trends along with surface manifestation observations and temperatures as they relate to known power producing systems. Our findings show a strong correlation between the presence and size of active flank fumarole areas and installed power production. Additionally, the majority of volcanic characteristics, including long-held anecdotal correlations related to magmatic composition or size, have limited to no correlation with power production potential. Notable exceptions are correlations between greater power yield from geothermal systems associated with older (Pleistocene) caldera systems


    K.J. Coppersmith


    A probabilistic volcanic hazard analysis (PVHA) was conducted in 1996 for the proposed repository at Yucca Mountain, Nevada. Based on data gathered by the Yucca Mountain Project over the course of about 15 years, the analysis integrated the judgments of a panel of ten volcanic experts using methods of formal expert elicitation. PVHA resulted in a probability distribution of the annual frequency of a dike intersecting the repository, which ranges from 10E-7 to 10E-10 (mean 1.6 x 10E-8). The analysis incorporates assessments of the future locations, rates, and types of volcanic dikes that could intersect the repository, which lies about 300 m below the surface. A particular focus of the analysis is the quantification of uncertainties. Since the 1996 PVHA, additional aeromagnetic data have been collected in the Yucca Mountain region, including a high-resolution low-altitude survey. A number of anomalies have been identified within alluvial areas and modeling suggests that some of these may represent buried eruptive centers (basaltic cinder cones). A program is currently underway to drill several of the anomalies to gain information on their origin and, if basalt, their age and composition. To update the PVHA in light of the new aeromagnetic and drilling data as well as other advancements in volcanic hazard modeling over the past decade, the expert panel has been reconvened and the expert elicitation process has been fully restarted. The analysis requires assessments of the spatial distribution of igneous events, temporal distributions, and geometries and characteristics of future events (both intrusive and extrusive). The assessments are for future time periods of 10,000 years and 1,000,000 years. Uncertainties are being quantified in both the conceptual models that define these elements as well as in the parameters for the models. The expert elicitation process is centered around a series of workshops that focus on the available data; alternative approaches to

  17. Friction in volcanic environments

    Kendrick, Jackie E.; Lavallée, Yan


    Volcanic landscapes are amongst the most dynamic on Earth and, as such, are particularly susceptible to failure and frictional processes. In rocks, damage accumulation is frequently accompanied by the release of seismic energy, which has been shown to accelerate in the approach to failure on both a field and laboratory scale. The point at which failure occurs is highly dependent upon strain-rate, which also dictates the slip-zone properties that pertain beyond failure, in scenarios such as sector collapse and pyroclastic flows as well as the ascent of viscous magma. High-velocity rotary shear (HVR) experiments have provided new opportunities to overcome the grand challenge of understanding faulting processes during volcanic phenomena. Work on granular ash material demonstrates that at ambient temperatures, ash gouge behaves according to Byerlee's rule at low slip velocities, but is slip-weakening, becoming increasingly lubricating as slip ensues. In absence of ash along a slip plane, rock-rock friction induces cataclasis and heating which, if sufficient, may induce melting (producing pseudotachylyte) and importantly, vesiculation. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The shear-thinning behaviour and viscoelasticity of frictional melts yield a tendency for extremely unstable slip, and occurrence of frictional melt fragmentation. This velocity-dependence acts as an important feedback mechanism on the slip plane, in addition to the bulk composition, mineralogy and glass content of the magma, that all influence frictional behaviour. During sector collapse events and in pyroclastic density currents it is the frictional properties of the rocks and ash that, in-part, control the run-out distance and associated risk. In addition, friction plays an important role in the eruption of viscous magmas: In the conduit, the rheology of magma is integral

  18. Quantitative estimation of inter layers heterogeneity characteristics of volcanic reservoir: taking one member of Yingcheng formation in Xudong area for an example%火山岩储层层内非均质性定量评价——以松辽盆地徐东地区营城组一段为例



    Due to few researches on volcanic reservoir heterogeneity, and in order to deeply un- derstand the structural characteristics of reservoir in micro-scale and provide reference to the effective exploitation of volcanic reservoir, the characteristics of inter layer heterogeneity of volcanic reservoir were quantitatively studied. one member of Yingcheng cretaceous formation In this research, the volcanic gas reservoir of in Xudong area, Xushen gas field was taken as an example. At the same time, the genesis and impact factor of inter layer heterogeneity of vol- canic reservoir and its influence to the reservoir development are also discussed. In this process, 56 core analysis data and 275 statistics of samples of reservoir properties were ana- lyzed, and 32 well log interpretation data were used. Methods of geological statistics and arith- metical operation means were used. The methods of core analyses combined with methods of well logging results statistics used to study the characteristics of inter layers heterogeneity of volcanic reservoir are presented. The results show that the inter layer heterogeneity of studied horizon volcanic reservoir in the aimed area was the strongest in terms of mass, whereas the in- ter layer heterogeneity of the YCII1 single layer, which was the leading layer, was the weakest among the four layers with a vertical permeability of more than half the cross range permeabili- ty. As a whole, variations of reservoir permeability in cross range were far bigger than those in vertical direction. The impact factors of inter layer heterogeneity of volcanic reservoir include the structural functioning, volcanic eruption characteristics, volcanic lithology, volcanic litho- facies and diagenesis, where the structural functioning and diagenesis took the dominant roles. Taking the variation coefficient of permeability as an index, the reservoir development condi- tions were researched. The results show that the reservoir development often occurred in

  19. Obsidian hydration dating of volcanic events

    Friedman, I.; Obradovich, J.


    Obsidian hydration dating of volcanic events had been compared with ages of the same events determined by the 14C and KAr methods at several localities. The localities, ranging in age from 1200 to over 1 million yr, include Newberry Craters, Oregon; Coso Hot Springs, California; Salton Sea, California; Yellowstone National Park, Wyoming; and Mineral Range, Utah. In most cases the agreement is quite good. A number of factors including volcanic glass composition and exposuretemperature history must be known in order to relate hydration thickness to age. The effect of composition can be determined from chemical analysis or the refractive index of the glass. Exposure-temperature history requires a number of considerations enumerated in this paper. ?? 1981.

  20. Volcanic flood simulation of magma effusion using FLO-2D for drainage of a caldera lake at the Mt. Baekdusan

    Lee, Khil-Ha; Kim, Sung-Wook; Kim, Sang-Hyun


    Many volcanic craters and calderas are filled with large amounts of water that can pose significant flood hazards to downstream communities due to their high elevation and the potential for catastrophic releases of water. Recent reports pointed out the Baekdusan volcano that is located between the border of China and North Korea as a potential active volcano. Since Millennium Eruption around 1000 AD, smaller eruptions have occurred at roughly 100-year intervals, with the last one in 1903. Sudden release of huge volume of water stored in temporarily elevated caldera lakes are a recurrent feature of volcanic environments, due to the case with which outlet channels are blocked by and re-cut through, unwelded pyroclastic deposits. The volcano is showing signs of waking from a century-long slumber recently. Volcanic floods, including breakouts from volcanic lakes, can affect communities beyond the areas immediately affected by a volcanic eruption and cause significant hydrological hazards because floods from lake-filled calderas may be particularly large and high. Although a number of case studies have been presented in the literature, investigation of the underlying physical processes is required as well as a method for interpreting the process of the rapid release of water stored in a caldera lake. The development of various forecasting techniques to prevent and minimize economic and social damage is in urgent need. This study focuses on constructing a flood hazard map triggered by the magma effusion in the Baekdusan volcano. A physically-based uplift model was developed to compute the amount of water and time to peak flow. The ordinary differential equation was numerically solved using the finite difference method and Newton-Raphson iteration method was used to solve nonlinear equation. The magma effusion rate into the caldera lake is followed by examples at other volcanic activities. As a result, the hydrograph serves as an upper boundary condition when hydrodynamic

  1. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    Søager, Nina

    The extensive Quaternary volcanism in the Payenia volcanic province, Mendoza, Argentina, is investigated in this study by major and trace element analyses, Sr, Nd, Hf and Pb-isotopic analyses and Zr-Hf isotope dilution data on samples from almost the entire province. The samples are mainly...... in basalts from all the studied volcanic fields in Payenia is signs of lower crustal contamination indicating assimilation of, in some cases, large amounts of trace element depleted, mafic, plagioclase-bearing rocks. The northern Payenia is dominated by backarc basalts erupted between late Pliocene to late...

  2. Volcanism-sedimentation interaction in the Campo de Calatrava Volcanic Field (Spain): a magnetostratigraphic and geochronological study

    Herrero-Hernández, Antonio; López-Moro, Francisco Javier; Gallardo-Millán, José Luis; Martín-Serrano, Ángel; Gómez-Fernández, Fernando


    This work focuses on the influence of Cenozoic volcanism of the Campo de Calatrava volcanic field on the sedimentation of two small continental basins in Spain (Argamasilla and Calzada-Moral basins). The volcanism in this area was mainly monogenetic, according to the small-volume volcanic edifices of scoria cones that were generated and the occurrence of tuff rings and maars. A sedimentological analysis of the volcaniclastic deposits led to the identification of facies close to the vents, low-density (dilute) pyroclastic surges, secondary volcanic deposits and typical maar deposits. Whole-rock K/Ar dating, together with palaeomagnetic constraints, yielded an age of 3.11-3.22 Ma for the onset of maar formation, the deposition finished in the Late Gauss-Early Matuyana. Using both techniques and previous paleontological data allowed it to be inferred that the maar formation and the re-sedimentation stage that occurred in Argamasilla and Calzada-Moral basins were roughly coeval. The occurrence of syn-eruption volcaniclastic deposits with small thicknesses that were separated by longer inter-eruption periods, where fluvial and lacustrine sedimentation was prevalent, together with the presence of small-volume volcanic edifices indicated that there were short periods of volcanic activity in this area. The volcanic activity was strongly controlled by previous basement faults that favoured magma feeding, and the faults also controlled the location of volcanoes themselves. The occurrence of the volcanoes in the continental basins led to the creation of shallow lakes that were related to the maar formation and the modification of sedimentological intra-basinal features, specifically, valley slope and sediment load.

  3. Boundary of the southwestern Nevada volcanic field from Laczniak and others (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the southwestern Nevada volcanic field (SWNVF), an area of thick, regionally distributed volcanic rocks within the...

  4. Boundary of the southwestern Nevada volcanic field from Laczniak and others (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the southwestern Nevada volcanic field (SWNVF), an area of thick, regionally distributed volcanic rocks within the...

  5. Volcanic hazard assessment for the Canary Islands (Spain) using extreme value theory

    Sobradelo, R.; Martí, J.; Mendoza-Rosas, A. T.; Gómez, G.


    The Canary Islands are an active volcanic region densely populated and visited by several millions of tourists every year. Nearly twenty eruptions have been reported through written chronicles in the last 600 yr, suggesting that the probability of a new eruption in the near future is far from zero. This shows the importance of assessing and monitoring the volcanic hazard of the region in order to reduce and manage its potential volcanic risk, and ultimately contribute to the design of appropriate preparedness plans. Hence, the probabilistic analysis of the volcanic eruption time series for the Canary Islands is an essential step for the assessment of volcanic hazard and risk in the area. Such a series describes complex processes involving different types of eruptions over different time scales. Here we propose a statistical method for calculating the probabilities of future eruptions which is most appropriate given the nature of the documented historical eruptive data. We first characterize the eruptions by their magnitudes, and then carry out a preliminary analysis of the data to establish the requirements for the statistical method. Past studies in eruptive time series used conventional statistics and treated the series as an homogeneous process. In this paper, we will use a method that accounts for the time-dependence of the series and includes rare or extreme events, in the form of few data of large eruptions, since these data require special methods of analysis. Hence, we will use a statistical method from extreme value theory. In particular, we will apply a non-homogeneous Poisson process to the historical eruptive data of the Canary Islands to estimate the probability of having at least one volcanic event of a magnitude greater than one in the upcoming years. This is done in three steps: First, we analyze the historical eruptive series to assess independence and homogeneity of the process. Second, we perform a Weibull analysis of the distribution of repose

  6. Volcanic hazard assessment for the Canary Islands (Spain using extreme value theory

    R. Sobradelo


    Full Text Available The Canary Islands are an active volcanic region densely populated and visited by several millions of tourists every year. Nearly twenty eruptions have been reported through written chronicles in the last 600 yr, suggesting that the probability of a new eruption in the near future is far from zero. This shows the importance of assessing and monitoring the volcanic hazard of the region in order to reduce and manage its potential volcanic risk, and ultimately contribute to the design of appropriate preparedness plans. Hence, the probabilistic analysis of the volcanic eruption time series for the Canary Islands is an essential step for the assessment of volcanic hazard and risk in the area. Such a series describes complex processes involving different types of eruptions over different time scales. Here we propose a statistical method for calculating the probabilities of future eruptions which is most appropriate given the nature of the documented historical eruptive data. We first characterize the eruptions by their magnitudes, and then carry out a preliminary analysis of the data to establish the requirements for the statistical method. Past studies in eruptive time series used conventional statistics and treated the series as an homogeneous process. In this paper, we will use a method that accounts for the time-dependence of the series and includes rare or extreme events, in the form of few data of large eruptions, since these data require special methods of analysis. Hence, we will use a statistical method from extreme value theory. In particular, we will apply a non-homogeneous Poisson process to the historical eruptive data of the Canary Islands to estimate the probability of having at least one volcanic event of a magnitude greater than one in the upcoming years. This is done in three steps: First, we analyze the historical eruptive series to assess independence and homogeneity of the process. Second, we perform a Weibull analysis of the

  7. Io. [theories concerning volcanic activity

    Johnson, T. V.; Soderblom, L. A.


    A report on the continuing investigation of Io is presented. Gravitational resonance is discussed as the cause of Io's volcanism, and the volcanic activity is explained in terms of sulfur chemistry. Theories concerning the reasons for the two main types of volcanic eruptions on Io are advanced and correlated with geographical features of the satellite. The sulfur and silicate models of the calderas are presented, citing the strengths and weaknesses of each. Problems of the gravitational resonance theory of Io's heat source are then described. Finally, observations of Io planned for the Galileo mission are summarized.

  8. Volcanic plumes fast detection: a methodological proposal for an integrated approach

    Bernabeo, R. Alberto; Tositti, Laura; Brattich, Erika


    The behaviour of erupting volcanoes ranges from the quiet, steady effusion of lava to highly explosive eruptions. Therefore volcanic eruptions may present a direct threat to the safety of aircraft in flight and major operational difficulties at aerodromes and in airspaces located downwind the resulting volcanic ash cloud, in particular when eruptions are of high intensity and/or prolonged. Since volcanic ash clouds and gases are not displayed on either airborne or ATC radar and are extremely difficult to identify at night, pilots must rely on reports from air traffic controllers and from other pilots to determine the location of an ash cloud or gases. As a result, there is a clear need to develop extra tools enabling the timely on-board sensing of volcanic plumes for the sake of safety purposes. Large scale eruptions may eject many cubic kilometres of glass particles and pulverized rock (volcanic ash) as well as corrosive/hazardous gases high into the atmosphere, potentially over a wide area for timescales ranging from hours to weeks or even months. Volcanic ash consists mostly of sharp-edged, hard glass particles and pulverized rock. It is very abrasive and, being largely composed of siliceous materials, has a melting temperature below the operating temperature of modern turbine engines at cruise thrust. A volcanic plume in fact contains a complex mixture of water vapour, sulphur dioxide (producing sulphuric acid as a result of gas-to particle conversions reaction catalysed by iron in cloud droplets), chlorine and other halogens, and trace elements which are highly reactive and may interact with the mineral particles to produce corrosive effects hazardous to both airframes and human health. Remotely piloted aircraft system (RPAS) or Unmanned aerial vehicles (UAV) are slowly becoming efficient platforms - with dedicated miniaturized sensors that can be used in scientific/commercial remote sensing applications - and are of fundamental support to the planning

  9. Late Pleistocene ages for the most recent volcanism and glacial-pluvial deposits at Big Pine volcanic field, California, USA, from cosmogenic 36Cl dating

    Vazquez, Jorge A.; Woolford, Jeff M


    The Big Pine volcanic field is one of several Quaternary volcanic fields that poses a potential volcanic hazard along the tectonically active Owens Valley of east-central California, and whose lavas are interbedded with deposits from Pleistocene glaciations in the Sierra Nevada Range. Previous geochronology indicates an ∼1.2 Ma history of volcanism, but the eruption ages and distribution of volcanic products associated with the most-recent eruptions have been poorly resolved. To delimit the timing and products of the youngest volcanism, we combine field mapping and cosmogenic 36Cl dating of basaltic lava flows in the area where lavas with youthful morphology and well-preserved flow structures are concentrated. Field mapping and petrology reveal approximately 15 vents and 6 principal flow units with variable geochemical composition and mineralogy. Cosmogenic 36Cl exposure ages for lava flow units from the top, middle, and bottom of the volcanic stratigraphy indicate eruptions at ∼17, 27, and 40 ka, revealing several different and previously unrecognized episodes of late Pleistocene volcanism. Olivine to plagioclase-pyroxene phyric basalt erupted from several vents during the most recent episode of volcanism at ∼17 ka, and produced a lava flow field covering ∼35 km2. The late Pleistocene 36Cl exposure ages indicate that moraine and pluvial shoreline deposits that overlie or modify the youngest Big Pine lavas reflect Tioga stage glaciation in the Sierra Nevada and the shore of paleo-Owens Lake during the last glacial cycle.

  10. Volcanic hazard impacts to critical infrastructure: A review

    Wilson, G.; Wilson, T. M.; Deligne, N. I.; Cole, J. W.


    Effective natural hazard risk assessment requires the characterisation of both hazards and vulnerabilities of exposed elements. Volcanic hazard assessment is at an advanced state and is a considerable focus of volcanic scientific inquiry, whereas comprehensive vulnerability assessment is lacking. Cataloguing and analysing volcanic impacts provide insight on likely societal and physical vulnerabilities during future eruptions. This paper reviews documented disruption and physical damage of critical infrastructure elements resulting from four volcanic hazards (tephra fall, pyroclastic density currents, lava flows and lahars) of eruptions in the last 100 years. We define critical infrastructure as including energy sector infrastructure, water supply and wastewater networks, transportation routes, communications, and critical components. Common trends of impacts and vulnerabilities are summarised, which can be used to assess and reduce volcanic risk for future eruptions. In general, tephra falls cause disruption to these infrastructure sectors, reducing their functionality, whilst flow hazards (pyroclastic density currents, lava flows and lahars) are more destructive causing considerable permanent damage. Volcanic risk assessment should include quantification of vulnerabilities and we challenge the volcanology community to address this through the implementation of a standardised vulnerability assessment methodology and the development and use of fragility functions, as has been successfully implemented in other natural hazard fields.

  11. Volcanic hazards on the Island of Hawaii

    Mullineaux, Donal Ray; Peterson, Donald W.


    Volcanic hazards on the Island of Hawaii have been determined to be chiefly products of eruptions: lava flows, falling fragments, gases, and particle-and-gas clouds. Falling fragments and particle-and-gas clouds can be substantial hazards to life, but they are relatively rare. Lava flows are the chief hazard to property; they are frequent and cover broad areas. Rupture, subsidence, earthquakes, and sea waves (tsunamis) caused by eruptions are minor hazards; those same events caused by large-scale crustal movements, however, are major hazards to both life and property. Volcanic hazards are greatest on Mauna Loa and Kilauea, and the risk is highest along the rift zones of those volcanoes. The hazards are progressively less severe on Hualalai, Mauna Kea, and Kohala volcanoes. Some risk from earthquakes extends across the entire island, and the risk from tsunamis is high all along the coast. The island has been divided into geographic zones of different relative risk for each volcanic hazard, and for all those hazards combined. Each zone is assigned a relative risk for that area as a whole; the degree of risk varies within the zones, however, and in some of them the risk decreases gradationally across the entire zone. Moreover, the risk in one zone may be locally as great or greater than that at some points in the zone of next higher overall risk. Nevertheless, the zones can be highly useful for land-use planning. Planning decisions to which the report is particularly applicable include the selection of kinds of structures and kinds of land use that are appropriate for the severity and types of hazards present. For example, construction of buildings that can resist a lava flow is generally not feasible, but it is both feasible and desirable to build structures that can resist falling rock fragments, earthquakes, and tsunamis in areas where risk from those hazards is relatively high. The report can also be used to select sites where overall risk is relatively low, to

  12. Volcanic eruptions observed with infrasound

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.


    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  13. Los volcanes y los hombres

    García, Carmen


    Desde las entrañas de la tierra, los volcanes han creado la atmósfera, el agua de los océanos, y esculpido los relieves del planeta: son, pues, los zahoríes de la vida. Existen volcanes que los hombres explotan o cultivan, y otros sobre los cuales se han construido observatorios en los que se llevan a cabo avanzadas investigaciones científicas.

  14. Volcanic hazards and aviation safety

    Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,


    An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

  15. Volcanic Zone, New Zealand

    Graham J. Weir


    Full Text Available A conceptual model of the Taupo Volcanic Zone (TVZ is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

  16. Sedimentary-volcanic tuffs formed during the early Middle Triassic volcanic event in Guizhou Province and their stratigraphic significance

    XIAO Jiafei; HU Ruizhong


    The sedimentary-volcanic tuff (locally called "green-bean rock") formed during the early Middle Triassic volcanic event in Guizhou Province is characterized as being thin, stable, widespread, short in forming time and predominantly green in color. The green-bean rock is a perfect indicator for stratigraphic division. Its petrographic and geochemical features are unique, and it is composed mainly of glassy fragments and subordinately of crystal fragments and volcanic ash balls. Analysis of the major and trace elements and rare-earth elements (REE), as well as the related diagrams, permits us to believe that the green-bean rock is acidic volcanic material of the calc-alkaline series formed in the Indosinian orogenic belt on the Sino-Vietnam border, which was atmospherically transported to the tectonically stable areas and then deposited as sedimentary-volcanic rocks there. According to the age of green-bean rock, it is deduced that the boundary age of the Middle-Lower Triassic overlain by the sedimentary-volcanic tuff is about 247 Ma.

  17. Age, distance, and geochemical evolution within a monogenetic volcanic field: Analyzing patterns in the Auckland Volcanic Field eruption sequence

    Corvec, Nicolas Le; Bebbington, Mark S.; Lindsay, Jan M.; McGee, Lucy E.


    The Auckland Volcanic Field (AVF) is a young active monogenetic basaltic field, which contains ˜50 volcanoes scattered across the Auckland metropolitan area. Understanding the temporal, spatial, and chemical evolution of the AVF during the last c.a. 250 ka is crucial in order to forecast a future eruption. Recent studies have provided new age constraints and potential temporal sequences of the past eruptions within the AVF. We use this information to study how the spatial distribution of the volcanic centers evolves with time, and how the chemical composition of the erupted magmas evolves with time and space. We seek to develop a methodology which compares successive eruptions to describe the link between geochemical and spatiotemporal evolution of volcanic centers within a monogenetic volcanic field. This methodology is tested with the present day data of the AVF. The Poisson nearest neighbor analysis shows that the spatial behavior of the field has been constant overtime, with the spatial distribution of the volcanic centers fitting the Poisson model within the significance levels. The results of the meta-analysis show the existence of correlations between the chemical composition of the erupted magmas and distance, volume, and time. The apparent randomness of the spatiotemporal evolution of the volcanic centers observed at the surface is probably influenced by the activity of the source. The methodology developed in this study can be used to identify possible relationships between composition trends and volume, time and/or distance to the behavior of the source, for successive eruptions of the AVF.

  18. Records of volcanic events since AD 1800 in the East Rongbuk ice core from Mt. Qomolangma

    XU JianZhong; KASPARI S.; HOU ShuGui; KANG ShiChang; QIN DaHe; REN JiaWen; MAYEWSKI p


    Continuous Bi profile of the East Rongbuk (ER) ice core near Mr.Qomolangma reveals nine major volcanic events since AD 1800.Compared with Volcanic Explosivity Index (VEI),it shows that the con-centrations of Bi in the ER ice core can reflect the major volcanic events within the key areas.This provides a good horizon layer for ice core dating,as well as a basis for reconstructing a long sequence of volcanic records from the Qinghai-Xizang (Tibet) Plateau ice cores.

  19. Andisols from Tondano Area, North Sulawesi: Properties and Classification



    Full Text Available Three pedons of Andisol (TN-1, TN-2 and TN-3 developed from young volcanic materials of the Lokon, Soputan, and Lengkoan volcanoes respectively in the Tondano area, North Sulawesi, were studied in the field, and 18 soil samples were analysed in the laboratory for physical, chemical, and mineralogical properties, and they were classified according to Keys to Soil Taxonomy 2003. The results indicated that all the pedons meet the requirements of the andic soil properties, and thus classified into Andisol order. Pedon TN-1 meets bulk density 85%, and (Alo + 0.5Feo content extracted by ammonium oxalate > 2.0%, while pedons TN-2 and TN-3 meet the requirements of P retention > 25%, (Alo + 0.5Feo content > 0.4%, volcanic glass content > 5%, and value of [%(Alo+0.5Feo x 15.625 + (% volcanic glass] is > 36.25. Composition of sand mineral fraction indicate that pedon TN-1 and TN-3 show andesitic to basaltic volcanic materials, whereas pedon TN-2 with high olivin content belongs to basaltic volcanic materials. Clay minerals of all the pedons was dominated by hydrated-halloysite with few of disordered-kaolinite, which indicated a little weathering of the pedons. The pedons were classified at family level as Typic Hapludand, medial, amorphic, isothermic (TN-1, Humic Udivitrand, ashy, amorphic, isothermic (TN-2, and Alfic Hapludand, medial, glassy, isothermic (TN-3.

  20. More efficient irrigation may compensate for increases in irrigation water requirements due to climate change in the Mediterranean area

    Fader, Marianela; Shi, Sinan; von Bloh, Werner; Bondeau, Alberte; Cramer, Wolfgang


    Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. We will present a recently published study1 that estimates the current level of water demand for Mediterranean agriculture and simulates the potential impacts of climate change, population growth and transitions to water-saving irrigation and conveyance technologies. The results indicate that, at present, Mediterranean region could save 35% of water by implementing more efficient irrigation and conveyance systems, with large differences in the saving potentials across countries. Under climate change, more efficient irrigation is of vital importance for counteracting increases in irrigation water requirements. The Mediterranean area as a whole might face an increase in gross irrigation requirements between 4% and 18% from climate change alone by the end of the century if irrigation systems and conveyance are not improved. Population growth increases these numbers to 22% and 74%, respectively, affecting mainly the Southern and Eastern Mediterranean. However, improved irrigation technologies and conveyance systems have large water saving potentials, especially in the Eastern Mediterranean. Both the Eastern and the Southern Mediterranean would need around 35% more water than today if they could afford some degree of modernization of irrigation and conveyance systems and benefit from the CO2-fertilization effect. However, in some scenarios water scarcity may constrain the supply of the irrigation water needed in future in Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain. In this study, vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL ("Lund-Potsdam-Jena managed Land") after a large development2 that comprised the improved representation of Mediterranean crops.

  1. Fluid-magmatic systems and volcanic centers in Northern Caucasus

    Sobisevich, Alexey L.; Masurenkov, Yuri P.; Pouzich, Irina N.; Laverova, Ninel I.


    The central segment of Alpine mobile folded system and the Greater Caucasus is considered with respect to fluid-magmatic activity within modern and Holocene volcanic centers. A volcanic center is a combination of volcanoes, intrusions, and hydrothermal features supported by endogenous flow of matter and energy localised in space and steady in time; responsible for magma generation and characterized by structural representation in the form of circular dome and caldera associations. Results of complimentary geological and geophysical studies carried out in the Elbrus volcanic area and the Pyatogorsk volcanic center are presented. The deep magmatic source and the peripheral magmatic chamber of the Elbrus volcano are outlined via comparative analysis of geological and experimental geophysical data (microgravity studies, magneto-telluric profiling, temperature of carbonaceous mineral waters). It has been determined that the peripheral magmatic chamber and the deep magmatic source of the volcano are located at depths of 0-7 and 20-30 km below sea level, respectively, and the geothermal gradient beneath the volcano is 100°C/km. In this study, analysis of processes of modern heat outflux produced by carbonaceous springs in the Elbrus volcanic center is carried out with respect to updated information about spatial configuration of deep fluid-magmatic structures of the Elbrus volcano. It has been shown, that degradation of the Elbrus glaciers throughout the historical time is related both to climatic variations and endogenic heat. The stable fast rate of melting for the glaciers on the volcano's eastern slope is of theoretical and practical interest as factors of eruption prognosis. The system approach to studying volcanism implies that events that seem to be outside the studied process should not be ignored. This concerns glaciers located in the vicinity of volcanoes. The crustal rocks contacting with the volcanism products exchange matter and energy between each other

  2. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang


    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  3. Quaternary volcanism in the Acambay graben, Mexican Volcanic Belt: Re-evaluation for potential volcanic danger in central Mexico

    Aguirre-Diaz, G. J.; Pedrazzi, D.; Lacan, P.; Roldan-Quintana, J.; Ortuňo, M.; Zuniga, R. R.; Laurence, A.


    The Mexican Volcanic Belt (MVB) is best known for the major active stratovolcanoes, such as Popocatépetl, Citlaltépetl and Colima. The most common stratovolcanoes in this province are modest-size cones with heights of 800 to 1000 m. Examples are Tequila, Sangangüey, Las Navajas, Culiacán, La Joya, El Zamorano, Temascalcingo and Altamirano; these last two were formed within the Acambay Graben in central MVB. The Acambay graben (20 x 70 km) is 100 km to the NW of Mexico City, with E-W trending seismically active normal faults; in particular the Acambay-Tixmadejé fault related to a mB =7 earthquake in 1912. Within the graben there are many volcanic structures, including calderas, domes, cinder cones and stratovolcanoes; Temascalcingo and Altamirano are the largest, with about 800 and 900 m heights, respectively. Temascalcingo is mostly composed of dacitic lavas and block and ash flow deposits. Includes a 3 x 2.5 km summit caldera and a magmatic sector collapse event with the associated debris avalanche deposit. 14C ages of 37-12 ka correspond to the volcano's latest phases that produced pyroclastic deposits. A major plinian eruption formed the San Mateo Pumice with an age of <20 Ka. Altamirano volcano is poorly studied; it is andesitic-dacitic, composed of lavas, pyroclastic flow deposits, and pumice fallouts. Morphologically is better preserved than Temascalcingo, and it should be younger. 14C ages of 4.0-2.5 ka were performed in charcoal within pyroclastic flow deposits that apparently were erupted from Altamirano. An undated 3 m thick pumice fallout on the flanks of Altamirano volcano could be also Holocene. It represents a major explosive event. The relatively young ages found in volcanic deposits within the Acambay graben raise the volcanic danger level in this area, originally thought as an inactive volcanic zone. The two major volcanoes, Temascalcingo and Altamirano, should be considered as dormant volcanoes that could restart activity at any time. We

  4. Early Cretaceous volcanic mechanism in Jianshan of Xingcheng area,Liaoning and its lithogeochemical characteristics%辽宁兴城尖山早白垩世火山机构及岩石地球化学特征

    王睿; 李世超; 刘正宏; 秦硕; 黄鸿琨; 杨进益; 苗立志


    The petrology and petrography of Jianshan volcanic mecganism in Xingcheng,Liaoning have been analyzed,and the geochemistry of hornblende andesites were studied.The results show that the hornblende andes-ites are characterized by SiO2 =58. 42%~60. 42%,MgO=1 . 39%~3. 08%,Mg#=31 ~50,Al2 O3 =1 6. 1 7%~1 7. 5%,Sr=(387~1 325) ×1 0 -6,Yb=(1 . 1 5 ~1 . 57) ×1 0 -6,Y=(1 2. 1 ~1 6. 8) ×1 0 -6,respec-tively.In addition,the volcanic rocks are enrichment in LREE and LILE and depletion in HREE,with high Sr and Sr/Y values and low Y and Yb values,showing the geochemical characteristics of adakite.However,they are low in Mg#,indicating the volcanic rocks may originate by partial melting of the thickened mafic lower crust,and could be related to the subduction of the Paleo-Pacific Plate beneath the Eurasian continent.%对辽宁兴城尖山火山机构的岩性-岩相学特征进行了分析,并对角闪安山岩进行了岩石地球化学研究。结果表明角闪安山岩SiO2=58.42%~60.42%,Al2 O3=16.17%~17.5%,MgO=1.39%~3.08%,Mg#=31~50,Sr=(387~1325)×10-6,Yb =(1.15~1.57)×10-6,Y =(12.1~16.8)×10-6。岩石富集轻稀土元素及大离子亲石元素,亏损高场强元素,高Sr和Sr/Y比值,低Y和Yb,显示出埃达克岩的地球化学特征,但其Mg#较低,表明该类火山岩可能是加厚的基性下地壳部分熔融的产物,可能与早白垩世太平洋板块的俯冲构造背景有关。

  5. Properties of volcanic soils in cold climate conditions

    Kuznetsova, Elena


    Layers of volcanic ash and the Andosol soils derived from them may play an important role in preserving snow and ice as well as developing permafrost conditions in the immediate vicinity of volcanoes of high elevation or those situated at high latitudes, and land areas, often distant from volcanic activity that are either prone to permafrost or covered by snow and ice, but are affected by the deposition of subaerial ash. The special properties of volcanic ash that are responsible are critically reviewed particularly in relation to recent research in Kamchatka in the Far East of Russia. Of particular importance are the thermal properties and the unfrozen water contents of ash layers and the rate at which the weathering of volcanic glass takes place. Volcanic glass is the most easily weathered component of volcanic ejecta (Shoji et al., 1993; Kimble et al., 2000). There are many specific environmental conditions, including paleoclimate and present-day climate, the composition of volcanic tephra and glaciation history, which cause the differences in weathering and development of volcanic ash soils (Zehetner et al., 2003). The preservation of in situ, unweathered, and unaltered surficial ash-fall deposits in the cold regions has important implications for paleoclimate and glacial history. Ash-fall deposits, which trap and preserve the soils, sediments, and landforms on which they fall, can be used to resolve local climate conditions (temperature and moisture) at the ash site during ash-fall deposition. The preservation of detailed sedimentary features (e.g. bedding in the ash, sharpness of stratigraphic contacts) can tell us about their post-depositional history, whether they have been redeposited by wind or water, or overridden by glaciers (Marchant et al., 1996). Weathering of volcanic glass results in the development of amorphous clay minerals (e.g. allophane, opal, palagonite) but this takes place much slower in cold than under warmer climate conditions. Only few

  6. The geochemistry of volcanic, plutonic and turbiditic rocks from Sumba, Indonesia

    Lytwyn, J.; Rutherford, E.; Burke, K.; Xia, C.


    Arc, which had been active in this area from at least ˜86 to approximately ˜31 Ma. The Great Indonesian Volcanic Arc was closely affiliated with, but may have occurred offshore Sundaland. Sumba is therefore a fragment of this oceanic (Aleutian-type) island arc and not a piece of the main Sundaland continent. The geochemistry of the igneous rocks on Sumba is inconsistent with what we would expect from an Andean-type Continental Arc. No continental basement is required to explain the composition and origin of the igneous rocks of Sumba.

  7. Automatized near-real-time short-term Probabilistic Volcanic Hazard Assessment of tephra dispersion before eruptions: BET_VHst for Vesuvius and Campi Flegrei during recent exercises

    Selva, Jacopo; Costa, Antonio; Sandri, Laura; Rouwet, Dmtri; Tonini, Roberto; Macedonio, Giovanni; Marzocchi, Warner


    Probabilistic Volcanic Hazard Assessment (PVHA) represents the most complete scientific contribution for planning rational strategies aimed at mitigating the risk posed by volcanic activity at different time scales. The definition of the space-time window for PVHA is related to the kind of risk mitigation actions that are under consideration. Short temporal intervals (days to weeks) are important for short-term risk mitigation actions like the evacuation of a volcanic area. During volcanic unrest episodes or eruptions, it is of primary importance to produce short-term tephra fallout forecast, and frequently update it to account for the rapidly evolving situation. This information is obviously crucial for crisis management, since tephra may heavily affect building stability, public health, transportations and evacuation routes (airports, trains, road traffic) and lifelines (electric power supply). In this study, we propose a methodology named BET_VHst (Selva et al. 2014) for short-term PVHA of volcanic tephra dispersal based on automatic interpretation of measures from the monitoring system and physical models of tephra dispersal from all possible vent positions and eruptive sizes based on frequently updated meteorological forecasts. The large uncertainty at all the steps required for the analysis, both aleatory and epistemic, is treated by means of Bayesian inference and statistical mixing of long- and short-term analyses. The BET_VHst model is here presented through its implementation during two exercises organized for volcanoes in the Neapolitan area: MESIMEX for Mt. Vesuvius, and VUELCO for Campi Flegrei. References Selva J., Costa A., Sandri L., Macedonio G., Marzocchi W. (2014) Probabilistic short-term volcanic hazard in phases of unrest: a case study for tephra fallout, J. Geophys. Res., 119, doi: 10.1002/2014JB011252

  8. Laboratory simulations of volcanic ash charging and conditions for volcanic lightning on Venus

    Airey, Martin; Warriner-Bacon, Elliot; Aplin, Karen


    to a high-precision electrometer. The separate effects of varying the atmospheric composition, temperature, and pressure on the charges attained and the relationship between particle size and charge polarity will be addressed, and the implications discussed. The key questions considered here are: (a) is volcanic activity a feasible mechanism for lightning generation on Venus, (b) how do the extreme environmental conditions on Venus affect the mechanisms required to generate lightning, (c) what are the implications for volcanic lightning's role in the emergence of life on other planets? [1] Navarro-Gonzalez, R. and Segura, A., (2001) Volcanic lightning and the availability of reactive nitrogen and phosphorus for chemical evolution. [2] Marcq, E., et al. (2012) Nature Geoscience, 1-4 [3] Shalygin, E.V., et al. (2015) Geophys. Res. Lett., 42 [4] Smrekar, S.E., et al. (2010) Science, 328, 5978, 605-608 [5] Russell, C.T., et al. (2008) Journal of Geophysical Research-Planets, 113 [6] Aplin, K.L. and Fischer, G. (In press) Weather, (preprint at [7] Takahashi, Y., et al. (2008) Space Sci. Rev., 137, 1-4, 317-334 [8] Airey, M.W., et al. (2015) Planetary and Space Science, 113-114, 33-48 [9] James, M.R., et al. (2000) Journal of Geophysical Research-Solid Earth, 105, B7, 16641-16649

  9. The nature and origin of mineral coatings on volcanic rocks of the Black Mountain, Stonewall Mountain and Kane Springs Wash volcanic centers in southern Nevada

    Taranik, J. V.; Noble, D. D.; Hsu, L. C.; Hutsinpiller, A.


    Four LANDSAT thematic mapping scenes in southern Nevada were requested at two different acquisition times in order to assess the effect of vegetation on the signature of the volcanic units. The remote sensing data acquisition and analysis portion are nearly completed. The LANDSAT thematic mapping data is of good quality, and image analysis techniques are so far successful in delineating areas with distinct spectral characteristics. Spectrally distinct areas were correlated with variations in surface coating and lithologies of the volcanic rocks.

  10. Crossmodal enhancement of visual orientation discrimination by looming sounds requires functional activation of primary visual areas: a case study.

    Cecere, Roberto; Romei, Vincenzo; Bertini, Caterina; Làdavas, Elisabetta


    Approaching or looming sounds are salient, potentially threatening stimuli with particular impact on visual processing. The early crossmodal effects by looming sounds (Romei, Murray, Cappe, & Thut, 2009) and their selective impact on visual orientation discrimination (Leo, Romei, Freeman, Ladavas, & Driver, 2011) suggest that these multisensory interactions may take place already within low-level visual cortices. To investigate this hypothesis, we tested a patient (SDV) with bilateral occipital lesion and spared residual portions of V1/V2. Accordingly, SDV׳s visual perimetry revealed blindness of the central visual field with some residual peripheral vision. In two experiments we tested for the influence of looming vs. receding and stationary sounds on SDV׳s line orientation discrimination (orientation discrimination experiment) and visual detection abilities (detection experiment) in the preserved or blind portions of the visual field, corresponding to spared and lesioned areas of V1, respectively. In the visual orientation discrimination experiment we found that SDV visual orientation sensitivity significantly improved for visual targets paired with looming sounds but only for lines presented in the partially preserved visual field. In the visual detection experiment, where SDV was required to simply detect the same stimuli presented in the orientation discrimination experiment, a generalised sound-induced visual improvement both in the intact and in blind portion of the visual field was observed. These results provide direct evidence that early visual areas are critically involved in crossmodal modulation of visual orientation sensitivity by looming sounds. Thus, a lesion in V1 prevents the enhancement of visual orientation sensitivity. In contrast, the same lesion does not prevent the visual detection enhancement by a sound, probably due to alternative visual pathways (e.g. retino-colliculo-extrastriate) which are usually spared in these patients and able to

  11. How a river course influences the species richness and ecological requirements on two opposite riverbanks in a forest area

    Bożenna Czarnecka


    Full Text Available The goal of the present research was to find correlations between the topographic attributes of a river valley and local ground-floor vegetation and its habitat requirements expressed by ecological indicator values (EIV, using the geographical information systems (GIS, digital elevation model (DEM, and multivariate statistical analysis. We paid special attention to the river course, which determines the differentiation in slope aspects and the amount of solar radiation reaching the ground surface. The model object was an almost latitudinal, ca. 4-km-long break section of the Sopot river, crossing the escarpment zone of the Central Roztocze Highlands, southeastern Poland. The main material comprised species lists (with estimated abundance for each ca. 200-m-long section, according to the river valley course, separately for the left and right riverbanks, 40 sections altogether, ca. 15 000 vegetation records, and physical and chemical soil measurements. A 3-meter resolution DEM was derived from a 1:10 000 topographic map. We calculated the correlations between the topographic attributes of the valley, species richness, and the EIVs for all the species recognized in each section of the valley. We found 241 herb plant species in the ground-floor vegetation of the study area. We did not find significant differences between the two riversides (61 ±13 species per one section for the left and 63 ±17 for the right side. Thus, the parallel course of the river valley does not change the species richness on a more “sunny” and more “shiny” riverbank. However, this factor “cooperating” with other topographic attributes of the valley significantly differentiates the shape of species showing various requirements for basic habitat resources: light, moisture, soil trophy, reaction, dispersion, and organic-matter content.

  12. Chronic exposure to volcanic air pollution and DNA damage in Furnas Volcano (São Miguel Island, Azores, Portugal) inhabitants

    Linhares, Diana; Garcia, Patricia; Silva, Catarina; Ferreira, Teresa; Barroso, Joana; Camarinho, Ricardo; Rodrigues, Armindo


    for confounding factors (age, gender, smoking and drinking status, and number of cigarettes smoked per day). Results demonstrated that levels of radon in the environment were significantly different in study and reference groups (115 Bq/m3 vs. 47 Bq/m3, respectively; p<0.001); in winter, radon measurements reached the highest values both in the study and the reference groups (809 Bq/m3 vs. 56 Bq/m3, respectively). The frequency of MNc in the study group was significantly higher than in the reference group (2.93‰ vs. 2.58‰, respectively; p=0.002). The OR for formation of MNc in the hydrothermal area was 1.5 (95% CI 1.07-2.02). A moderate and positive correlation was found between the frequency of MNc and 222Rn (rs = 0.459, p<0.001). To our knowledge this is the first study that clearly associates the exposure of volcanogenic indoor radon in inhabitants of hydrothermal areas and the DNA damage in human oral epithelial cells, evidencing that volcanic air pollution is a risk factor of carcinogenesis. Although the present findings require confirmation in larger studies, bio-monitoring for DNA damage is recommended for inhabitants of localities with active volcanism and mitigation measures such as restriction of building in certain areas should be taken into consideration in these volcanically active areas.

  13. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    Søager, Nina

    primitive basalts and trachybasalts but also more evolved samples from the retroarc region and the larger volcanoes Payún Matrú and Payún Liso are presented. The samples cover a broad range of compositions from intraplate lavas similar to ocean island basalts to arc andesites. A common feature found...... Pleistocene times. These basalts mark the end of a period of shallow subduction of the Nazca slab beneath the Payenia province and volcanism in the Nevado volcanic field apparently followed the downwarping slab in a north-northwest direction ending in the Northern Segment. The northern Payenia basalts...... the literature. The Nevado basalts have been modelled by 4-10 % melting of a primitive mantle added 1-5 % upper continental crust. In the southern Payenia province, intraplate basalts dominate. The samples from the Payún Matrú and Río Colorado volcanic fields are apparently unaffected by the subducting slab...

  14. 40Ar/39Ar dating, geochemistry, and isotopic analyses of the quaternary Chichinautzin volcanic field, south of Mexico City: implications for timing, eruption rate, and distribution of volcanism

    Arce, J. L.; Layer, P. W.; Lassiter, J. C.; Benowitz, J. A.; Macías, J. L.; Ramírez-Espinosa, J.


    Monogenetic structures located at the southern and western ends of the Chichinautzin volcanic field (Trans-Mexican Volcanic Belt, Central Mexico) yield 40Ar/39Ar ages ranging from 1.2 Ma in the western portion of the field to 1.0-0.09 Ma in the southern portion, all of which are older than the volcanic field. These new ages indicate: (1) an eruption rate of 0.47 km3/kyr, which is much lower than the 11.7 km3/kyr previously estimated; (2) that the Chichinautzin magmatism coexisted with the Zempoala (0.7 Ma) and La Corona (1.0 Ma) polygenetic volcanoes on the southern edge of Las Cruces Volcanic Range (Trans-Mexican Volcanic Belt); and confirm (3) that the drainage system between the Mexico and Cuernavaca basins was closed during early Pleistocene forming the Texcoco Lake. Whole-rock chemistry and Sr, Nd, and Pb isotopic data indicate heterogeneous magmatism throughout the history of Chichinautzin activity that likely reflects variable degrees of slab and sediment contributions to the mantle wedge, fractional crystallization, and crustal assimilation. Even with the revised duration of volcanism within the Chichinautzin Volcanic Field, its eruption rate is higher than most other volcanic fields of the Trans-Mexican Volcanic Belt and is comparable only to the Tacámbaro-Puruaran area in the Michoacán-Guanajuato Volcanic Field to the west. These variations in eruption rates among different volcanic fields may reflect a combination of variable subduction rates of the Rivera and Cocos plates along the Middle America Trench, as well as different distances from the trench, variations in the depth with respect to the subducted slab, or the upper plate characteristics.

  15. Atmospheric chemistry in volcanic plumes.

    von Glasow, Roland


    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  16. Global deprivation of brain-derived neurotrophic factor in the CNS reveals an area-specific requirement for dendritic growth.

    Rauskolb, Stefanie; Zagrebelsky, Marta; Dreznjak, Anita; Deogracias, Rubén; Matsumoto, Tomoya; Wiese, Stefan; Erne, Beat; Sendtner, Michael; Schaeren-Wiemers, Nicole; Korte, Martin; Barde, Yves-Alain


    Although brain-derived neurotrophic factor (BDNF) is linked with an increasing number of conditions causing brain dysfunction, its role in the postnatal CNS has remained difficult to assess. This is because the bdnf-null mutation causes the death of the animals before BDNF levels have reached adult levels. In addition, the anterograde axonal transport of BDNF complicates the interpretation of area-specific gene deletion. The present study describes the generation of a new conditional mouse mutant essentially lacking BDNF throughout the CNS. It shows that BDNF is not essential for prolonged postnatal survival, but that the behavior of such mutant animals is markedly altered. It also reveals that BDNF is not a major survival factor for most CNS neurons and for myelination of their axons. However, it is required for the postnatal growth of the striatum, and single-cell analyses revealed a marked decreased in dendritic complexity and spine density. In contrast, BDNF is dispensable for the growth of the hippocampus and only minimal changes were observed in the dendrites of CA1 pyramidal neurons in mutant animals. Spine density remained unchanged, whereas the proportion of the mushroom-type spine was moderately decreased. In line with these in vivo observations, we found that BDNF markedly promotes the growth of cultured striatal neurons and of their dendrites, but not of those of hippocampal neurons, suggesting that the differential responsiveness to BDNF is part of a neuron-intrinsic program.

  17. Evidence for volcanism in NW Ishtar Terra, Venus

    Gaddis, L.; Greeley, Ronald

    Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred large/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

  18. "Last mile" challenges to in situ volcanic data transmission

    J. F. B. D. Fonseca


    Full Text Available Scientists play a key role in volcanic risk mitigation, but rely heavily on fast access to data acquired in the vicinity of an active volcano. Hazardous volcanoes are often located in remote areas were telecommunications infrastructure is fragile. Besides being exposed directly to the volcanic hazard, the infrastructure in such remote areas can suffer also from "last mile" limitations derived from lack of market demand for data transmission services. In this paper, we report on the findings of FP7 MIAVITA project in the topic of volcanic data transmission. We draw on the contribution of partners from emergent or developing countries to identify the main bottlenecks and fragilities. We present also the results of an experiment conducted in Fogo island, Cape Verde, to test the availability of VSAT services adequate for volcanic monitoring. We warn against the false sense of security resulting from increasingly ubiquitous connectivity, and point out the lack of reliability of many consumer-type services, particularly during emergencies when such services are likely to crash due to excess of demand from the public. Finally, we propose guidelines and recommend best practices for the design of volcanic monitoring networks in what concerns data transmission. In particular, we advise that the data transmission equipment close to the exposed area should be owned, operated and maintained by the volcanic monitoring institution. We exemplify with the setup of the Fogo telemetric interface, which uses low-power licence-free radio modems to reach a robust point of entry into the public network at a suitable distance from the volcano.

  19. "Last mile" challenges to in situ volcanic data transmission

    Fonseca, J. F. B. D.; Faria, B. V. E.; Trindade, J.; Cruz, G.; Chambel, A.; Silva, F. M.; Pereira, R. L.; Vazão, T.


    Scientists play a key role in volcanic risk management, but rely heavily on fast access to data acquired in the vicinity of an active volcano. Hazardous volcanoes are often located in remote areas were telecommunications infrastructure is fragile. Besides being exposed directly to the volcanic hazard, the infrastructure in such remote areas can also suffer from "last mile" limitations derived from lack of market demand for data transmission services. In this paper, we report on the findings of the FP7 MIAVITA project in the topic of volcanic data transmission. We draw on the contribution of partners from emergent or developing countries to identify the main bottlenecks and fragilities. We also present the results of an experiment conducted on Fogo Island, Cape Verde, to test the availability of VSAT services adequate for volcanic monitoring. We warn against the false sense of security resulting from increasingly ubiquitous connectivity, and point out the lack of reliability of many consumer-type services, particularly during emergencies when such services are likely to crash due to excess of demand from the public. Finally, we propose guidelines and recommend best practices for the design of volcanic monitoring networks in what concerns data transmission. In particular, we advise that the data transmission equipment close to the exposed area should be owned, operated and maintained by the volcanic monitoring institution. We exemplify with the set-up of the Fogo telemetric interface, which uses low-power licence-free radio modems to reach a robust point of entry into the public network at a suitable distance from the volcano.

  20. A-type volcanics in Central Eastern Sinai, Egypt

    Samuel, M. D.; Moussa, H. E.; Azer, M. K.


    Alkaline rhyolitic and minor trachytic volcanics were erupted ˜580-530 Ma ago. They occur with their A-type intrusive equivalents in Sinai, southern Negev and southwestern Jordan. At Taba-Nuweiba district, these volcanics outcrop in three areas, namely, Wadi El-Mahash, Wadi Khileifiya and Gebel El-Homra. Mineralogically, they comprise alkali feldspars, iron-rich biotite and arfvedsonite together with rare ferro-eckermannite. Geochemically, the older rhyolitic volcanics are highly evolved, enriched in HFSE including REE and depleted in Ca, Mg, Sr and Eu. The rhyolitic rocks of Wadi El-Mahash and Gebel El-Homra are enriched in K 2O content (5.3-10.1 wt.%) and depleted in Na 2O content (0.08-2.97 wt.%), while the rhyolites of Wadi Khileifiya have normal contents of alkalis. Their REE patterns are uniform, parallel to subparallel, fractionated [(La/Yb) n = 5.4] and show prominent negative Eu-anomalies. They are classified as alkali rhyolites with minor comendites. The younger volcanics are classified as trachyandesite and quartz trachyte (56.6-62.9 wt.% SiO 2). Both older and younger volcanics represent two separate magmatic suites. The overall mineralogical and chemical characteristics of these volcanics are consistent with within plate tectonic setting. It is suggested that partial melting of crustal rocks yielded the source magma. Lithospheric extension and crustal rupture occurred prior to the eruption of these volcanics. The rather thin continental crust (˜35 km) as well as the continental upheaval and extensive erosion that preceded their emplacement favoured pressure release and increasing mantle contribution. The volatiles of the upper mantle were important agents for heat transfer, and sufficient for the anatexis of the crustal rocks. A petrogenetic hypothesis is proposed for the genesis of the recorded potassic and ultrapotassic rhyolitic rocks through the action of dissolved volatiles and their accumulation in the uppermost part of the magma chamber.

  1. The Sierra de Mil Cumbres, Michoacán, México: Transitional volcanism between the Sierra Madre Occidental and the Trans-Mexican Volcanic Belt

    Gómez-Vasconcelos, Martha Gabriela; Garduño-Monroy, Víctor Hugo; Macías, José Luis; Layer, Paul W.; Benowitz, Jeff A.


    The Sierra de Mil Cumbres is a Miocene volcanic range located in central México, in the north-eastern part of the State of Michoacán, near the city of Morelia. Structurally it is a ENE-trending horst that covers an area of 1022 km2 (approximately 20 km wide × 60 km long) and contains exposures of chemically-bimodal volcanism in the form of ignimbrites, lava domes, lava flows, cinder cones, and related deposits. The main volcanic manifestations of this range are the La Escalera Caldera (16.3-23 Ma), the Garnica Volcanic Complex (18.3-17.9 Ma), the Atécuaro Caldera (16.3-19.4 Ma), and the Indaparapeo Volcanic Complex (14.1-17.5 Ma). The Sierra de Mil Cumbres stands in space and time at the intersection between the Miocene-Recent Trans-Mexican Volcanic Belt and the Late Cretaceous-Early Miocene Sierra Madre Occidental, and so provides new insights into the geological evolution of central México. Arc volcanism in the Sierra de Mil Cumbres was initiated by a massive NNW-SSE extension, probably during the counterclockwise rotation of the Sierra Madre Occidental. New geological mapping, stratigraphic analysis, detailed geochemistry and 40Ar/39Ar geochronology demonstrates that this intra-plate volcanism was emplaced between 14 and 23 Ma.

  2. Geology and geochemistry of volcanic centers within the eastern half of the Sonoma volcanic field, northern San Francisco Bay region, California

    Sweetkind, Donald S.; Rytuba, James J.; Langenheim, V.E.; Fleck, Robert J.


    Volcanic rocks in the Sonoma volcanic field in the northern California Coast Ranges contain heterogeneous assemblages of a variety of compositionally diverse volcanic rocks. We have used field mapping, new and existing age determinations, and 343 new major and trace element analyses of whole-rock samples from lavas and tuff to define for the first time volcanic source areas for many parts of the Sonoma volcanic field. Geophysical data and models have helped to define the thickness of the volcanic pile and the location of caldera structures. Volcanic rocks of the Sonoma volcanic field show a broad range in eruptive style that is spatially variable and specific to an individual eruptive center. Major, minor, and trace-element geochemical data for intracaldera and outflow tuffs and their distal fall equivalents suggest caldera-related sources for the Pinole and Lawlor Tuffs in southern Napa Valley and for the tuff of Franz Valley in northern Napa Valley. Stratigraphic correlations based on similarity in eruptive sequence and style coupled with geochemical data allow an estimate of 30 km of right-lateral offset across the West Napa-Carneros fault zones since ~5 Ma.

  3. Assessment of Prospecting Potentiality for Superlarge Continental Volcanic Rock—Type Uranium Deposits in China

    陈贵华; 陈名佐; 等


    The superlarge continental volcanic rock-type uranium deposits,which were discovered abroad long ago,have not ye been reported up to now in China.This is an important problem that needs to be urgently solved by uranium geologists at present.In this paper,on the basis of analyzing the metallogenic settings and geological conditions of the superlarge continental volcanic rock-type uranium deposits discovered in the world along with the metallogenic characteristics of those of the same type in China,the space-time distribution patterns of continental volcanics and the metallogenic potential of main tectono-volcanic belts in China are discussed,and a synthetic conclusion has been drawn that there is a possibility to discover the superlarge continental volcanic rock-type uranium deposits in China.Moreover,it is evidenced that the Ganhang,Nanling,Yanliao,Da Hinggan Ling and other tectono-volcanic belts possess favorable geological conditions for the formation of ssuperlarge ore deposits of the continental volcanic rock type.The intersecting and overlapping locations of the aforementioned main belts with other tectono-volcanic(-intrusive)belts are the most potential areas where the superlarge continental volcanic rock-type uranium deposits would be found.

  4. Geopulsation, Volcanism and Astronomical Periods

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen


    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  5. Volcanic eruptions and solar activity

    Stothers, Richard B.


    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  6. Geochemical study for volcanic surveillance

    Panichi, C.; La Ruffa, G. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research Ghezzano, PI (Italy)


    For years, geologists have been striving to reconstruct volcanic eruptions from the analysis of pyroclastic deposits and lava flows on the surface of the earth and in the oceans. This effort has produced valuable information on volcanic petrology and magma generation, separation, mixing, crystallisation, and interaction with water in phreatomagmatic and submarine eruptions. The volcanological process are tied to the dynamics of the earth's crust and lithosphere. The mantle, subducted oceanic crust, and continental crust contain different rock types and are sources of different magmas. Magmas consist primarily of completely or partially molten silicates containing volatile materials either dissolved in the melt or as bubbles of gas. The silicate and volatile portions affect the physical properties of magma and, therefore, the nature of a volcanic eruption.

  7. Explosive volcanism and associated pressures - Implications for models of endogenically shocked quartz

    De Silva, S. L.; Wolff, J. A.; Sharpton, V. L.


    The nature of explosive volcanic phenomena and associated pressures, both from field and theoretical perspectives, is discussed. An endogenic origin for shocked quartz at the K/T boundary requires impulsive pressures greater than 60 kbars to be generated during explosive volcanism. Explosive volcanic eruptions which are events of sustained decompression may be initiated by impulsive explosions while the magnitudes of the overpressures are small. These maximum overpressures can be controlled mainly by the tensile strength of the rock surrounding the magma chamber-conduit system. Thus maximum overpressures in the volcanic environment are limited to less than 500 bars which are orders of magnitude less than those required for shock quartz (greater than 60 kbars). This observation is found to be consistent with the complete lack of field or petrographic evidence in support of shock metamorphism associated with volcanic eruptions and their products.

  8. Development and application of indices using large volcanic databases for a global hazard and risk assessment

    Brown, Sarah; Auker, Melanie; Cottrell, Elizabeth; Delgado Granados, Hugo; Loughlin, Sue; Ortiz Guerrero, Natalie; Sparks, Steve; Vye-Brown, Charlotte; Taskforce, Indices


    The Global Volcano Model (GVM) and IAVCEI were commissioned by the United Nations Office for Disaster Risk Reduction to produce a global assessment of volcanic hazard and risk for the Global Assessment Report 2015 (GAR15). This involved presenting both an introduction to volcanology and developing indices to assess hazard and risk on a global scale. To this end two open-access databases were of utmost importance: the Global Volcanism Program's Volcanoes of the World ( and the Large Magnitude Explosive Volcanic Eruptions database (LaMEVE; Indices were developed to enable a relative global assessment cognisant of data uncertainty and availability to broadly identify how hazard and risk varies around the world, the extent of monitoring and strengths and limitations in knowledge. The accessibility of both physical (e.g. volcano, eruption) and social data is crucial to our understanding of past behaviour, forecasting probable future behaviour and the potential impacts on communities. Such data is regionally highly variable and the eruption record worsens back in time. The Volcanic Hazard Index (VHI) was designed to quantify hazard levels globally, based on the Holocene eruption record. Vulnerability to eruptions was measured using the Population Exposure Index, which weights the population within 100 km of volcanoes by area and historical fatalities. The combination of these indices provides an indicator of population risk at individual volcanoes. The VHI was also combined with the total populations living within 30 km of volcanoes in each country to develop an understanding of the global distribution of volcano threat, and to rank countries by this measure. About half of the historically active volcanoes have insufficient information to adequately calculate VHI and these are highlighted as requiring future research. A database currently in development, GLOVOREMID, collates monitoring data to understand

  9. Probabilistic short-term volcanic hazard in phases of unrest: A case study for tephra fallout

    Selva, Jacopo; Costa, Antonio; Sandri, Laura; Macedonio, Giovanni; Marzocchi, Warner


    During volcanic crises, volcanologists estimate the impact of possible imminent eruptions usually through deterministic modeling of the effects of one or a few preestablished scenarios. Despite such an approach may bring an important information to the decision makers, the sole use of deterministic scenarios does not allow scientists to properly take into consideration all uncertainties, and it cannot be used to assess quantitatively the risk because the latter unavoidably requires a probabilistic approach. We present a model based on the concept of Bayesian event tree (hereinafter named BET_VH_ST, standing for Bayesian event tree for short-term volcanic hazard), for short-term near-real-time probabilistic volcanic hazard analysis formulated for any potential hazardous phenomenon accompanying an eruption. The specific goal of BET_VH_ST is to produce a quantitative assessment of the probability of exceedance of any potential level of intensity for a given volcanic hazard due to eruptions within restricted time windows (hours to days) in any area surrounding the volcano, accounting for all natural and epistemic uncertainties. BET_VH_ST properly assesses the conditional probability at each level of the event tree accounting for any relevant information derived from the monitoring system, theoretical models, and the past history of the volcano, propagating any relevant epistemic uncertainty underlying these assessments. As an application example of the model, we apply BET_VH_ST to assess short-term volcanic hazard related to tephra loading during Major Emergency Simulation Exercise, a major exercise at Mount Vesuvius that took place from 19 to 23 October 2006, consisting in a blind simulation of Vesuvius reactivation, from the early warning phase up to the final eruption, including the evacuation of a sample of about 2000 people from the area at risk. The results show that BET_VH_ST is able to produce short-term forecasts of the impact of tephra fall during a rapidly

  10. 西准噶尔马拉苏早泥盆世火山岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其大地构造意义%LA-ICP-MS zircon U-Pb geochronology, geochemical characteristics and tec-tonic significance of Early Devonian volcanic rocks in Malasu area, western Juggar Basin

    翁凯; 徐学义; 马中平; 孙吉明; 张涛


    The early Devonian strata in Malasu area is a set of littoral-neritic facies volcanic sedimentary rocks. This paper reports the zircon age and geochemical characteristics of the volcanic rocks. A lot of Neo-Archean and middle Neo-Proterozoic zircons indicate that this area contains ancient continental crust material. According to the values of major elements (SiO 2 52.38%~69.6%, Na2O 2.80%~4.85%, K2O 0.16%~0.96%, TiO2 0.5%~1.96%, Al2O3 14.62%~18.18%, MgO 1.08%~5.75%) and the values of Mg# (22.92~38), the volcanic rocks of Malasu area are characterized by high content of sodium and low content of potassium, and thus belong to low-po⁃tassium tholeiite series and calc-alkaline series. The volcanic rocks have significant negative Eu anomalies ( 0.83~0.83), total rare earth element values of 73×10-6~115×10-6, and LREE/HREE values of 2.66~3.25. The geochemical characteristics of basaltic andesite sam⁃ples are similar to those of typical volcanic arc basalts, being rich in large ion lithophile elements K, Rb, Ba, Sr and depleted in the high field strength elements Nb, Ta, Zr, Hf. The same characteristics of enrichment of LILE and depletion of HFSE for dacite por⁃ phyry samples reflect the addition of lots of crust-derived materials. The chondrite-normalized REE and primitive mantle-normal⁃ized alteration-resistant trace element patterns for the dacite porphyry are similar to the patterns of basaltic andesite, which suggests that they belong to the comagmatic evolutionary series. Comprehensive research shows that the volcanic rocks have the characteristics of island arc volcanic rocks, and were formed in the volcanic island arc environment in the process of plate subduction.%马拉苏地区早泥盆世地层为一套滨海—浅海相火山—沉积岩系,对其中的火山岩夹层进行锆石U-Pb同位素定年和岩石地球化学研究,定年结果显示有大量的新太古代和中新元古代锆石,表明该区存在古老的大陆地壳

  11. Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM): VOLCANIC AEROSOLS DERIVED FROM EMISSIONS

    Mills, Michael J. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Schmidt, Anja [School of Earth and Environment, University of Leeds, Leeds UK; Easter, Richard [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Solomon, Susan [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge Massachusetts USA; Kinnison, Douglas E. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Ghan, Steven J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Neely, Ryan R. [School of Earth and Environment, University of Leeds, Leeds UK; National Centre for Atmospheric Science, University of Leeds, Leeds UK; Marsh, Daniel R. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Conley, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Bardeen, Charles G. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Gettelman, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA


    Accurate representation of global stratospheric aerosol properties from volcanic and non-volcanic sulfur emissions is key to understanding the cooling effects and ozone-loss enhancements of recent volcanic activity. Attribution of climate and ozone variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the apparent rate of global average temperature increases, and variable recovery of the Antarctic ozone hole. We have developed a climatology of global aerosol properties from 1990 to 2014 calculated based on volcanic and non-volcanic emissions of sulfur sources. We have complied a database of volcanic SO2 emissions and plume altitudes for eruptions between 1990 and 2014, and a new prognostic capability for simulating stratospheric sulfate aerosols in version 5 of the Whole Atmosphere Community Climate Model, a component of the Community Earth System Model. Our climatology shows remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD), and with in situ measurements of aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD climatology represents a significant improvement over satellite-based analyses, which ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at mid- and high-latitudes. Our SAD climatology significantly improves on that provided for the Chemistry-Climate Model Initiative, which misses 60% of the SAD measured in situ. Our climatology of aerosol properties is publicly available on the Earth System Grid.

  12. Suitability of energy cone for probabilistic volcanic hazard assessment: validation tests at Somma-Vesuvius and Campi Flegrei (Italy)

    Tierz, Pablo; Sandri, Laura; Costa, Antonio; Zaccarelli, Lucia; Di Vito, Mauro Antonio; Sulpizio, Roberto; Marzocchi, Warner


    Pyroclastic density currents (PDCs) are gravity-driven hot mixtures of gas and volcanic particles which can propagate at high speed and cover distances up to several tens of kilometers around a given volcano. Therefore, they pose a severe hazard to the surroundings of explosive volcanoes able to produce such phenomena. Despite this threat, probabilistic volcanic hazard assessment (PVHA) of PDCs is still in an early stage of development. PVHA is rooted in the quantification of the large uncertainties (aleatory and epistemic) which characterize volcanic hazard analyses. This quantification typically requires a big dataset of hazard footprints obtained from numerical simulations of the physical process. For PDCs, numerical models range from very sophisticated (not useful for PVHA because of their very long runtimes) to very simple models (criticized because of their highly simplified physics). We present here a systematic and robust validation testing of a simple PDC model, the energy cone (EC), to unravel whether it can be applied to PVHA of PDCs. Using past PDC deposits at Somma-Vesuvius and Campi Flegrei (Italy), we assess the ability of EC to capture the values and variability in some relevant variables for hazard assessment, i.e., area of PDC invasion and maximum runout. In terms of area of invasion, the highest Jaccard coefficients range from 0.33 to 0.86 which indicates an equal or better performance compared to other volcanic mass-flow models. The p values for the observed maximum runouts vary from 0.003 to 0.44. Finally, the frequencies of PDC arrival computed from the EC are similar to those determined from the spatial distribution of past PDC deposits, with high PDC-arrival frequencies over an ˜8-km radius from the crater area at Somma-Vesuvius and around the Astroni crater at Campi Flegrei. The insights derived from our validation tests seem to indicate that the EC is a suitable candidate to compute PVHA of PDCs.

  13. Volcanism and global change conference set for 1992

    Papers are solicited for the AGU Chapman Conference on Climate, Volcanism, and Global Change, to be held March 23-27, 1992, in Hilo, Hawaii. Conference conveners are Stephen Self, University of Hawaii at Manoa, and Richard P. Turco, University of California, Los Angeles. Papers should focus on areas related to volcanic eruption dynamics and geochemistry, dispersion and removal of volcanogenic aerosols, effects on the atmosphere and climate, and signatures in sediments, ice cores, and tree rings. The conference will bring together a broad range of geophysicists whose research or interests involve volcanic eruptions and their impact. Results obtained from investigations of the El Chichón 1982 event and its aftermath are of particular interest for sessions dedicated to this specific, well-documented atmospheric perturbation.

  14. 准噶尔盆地中拐地区石炭—二叠纪火山岩特征及构造环境分析%Geochemical characteristics and tectonic setting of the Carboniferous-Permian volcanic rocks in Zhongguai area northwestern Junggar Basin

    孙国强; 史基安; 张顺存; 陈吉; 贾艳艳


    中拐地区位于准噶尔盆地西北缘,是在石炭纪—早二叠世挤压应力场作用下形成的宽缓鼻状古隆起.石炭—二叠纪火山岩是主要的含油层系之一,到目前为止已发现了多个油气藏和出油气点,显示出良好的勘探前景.根据系统、精细的地震资料解释,中拐地区在石炭—二叠纪时期主要存在4期构造运动,分别对应4个不整合面:1)石炭系与二叠系之间;2)二叠系佳木河组与下乌尔禾组之间;3)二叠系下乌尔禾组与上乌尔禾组之间;4)二叠系上乌尔禾组与三叠系百口泉组之间.通过对中拐地区石炭—二叠纪火山岩的全岩元素分析表明,该区域主要为中-酸性的安山岩、英安岩和流纹岩及火山角砾岩和凝灰岩为主,其中SiO2的含量普遍较高,平均含量达到了67%,判定中拐地区的石炭—二叠纪火山岩喷发环境应位于岛弧体系的大陆内侧,在喷发过程中经历过陆壳的熔融作用.结合前人对周缘火山岩的研究,认为石炭—二叠纪时期中拐地区由岛弧环境逐渐进入陆内演化阶段,三叠纪开始进入稳定的沉积演化时期.%Zhong-Guai area is located in the Northwest margin of Junggar Basin, it is a broad nose palaeohigh formed in compressional stress field of Carboniferous Early Permain Period. Carboniferous-Permain volcanic rock is one of the mainly oil-bearing series, until now many hydrocarbon reservoirs and oil entry points are discovered, and showing good exploration prospects. According to systematic and elaborate seismic data interpretation, Zhong-Guai area have four tectonic movements in the Carboniferous-Permian period, corresponding to four unconformity respectively: 1 ) Between the Carboniferous and Permian system; 2) Between the Jiamuhe and Xiawuerhe Formation of Permian system; 3 ) Between the Xiawuerhe and Shangwuerhe Formation of Permian system; 4) Between the Xiawuerhe Formation of Permian system and Baikouquan Formation of

  15. Modeling transport and aggregation of volcanic ash particles

    Costa, Antonio; Folch, Arnau; Macedonio, Giovanni; Durant, Adam


    A complete description of ash aggregation processes in volcanic clouds is an very arduous task and the full coupling of ash transport and ash aggregation models is still computationally prohibitive. A large fraction of fine ash injected in the atmosphere during explosive eruptions aggregate because of complex interactions of surface liquid layers, electrostatic forces, and differences in settling velocities. The formation of aggregates of size and density different from those of the primary particles dramatically changes the sedimentation dynamics and results in lower atmospheric residence times of ash particles and in the formation of secondary maxima of tephra deposit. Volcanic ash transport models should include a full aggregation model accounting for all particle class interaction. However this approach would require prohibitive computational times. Here we present a simplified model for wet aggregation that accounts for both atmospheric and volcanic water transport. The aggregation model assumes a fractal relationship for the number of primary particles in aggregates, average efficiencies factors, and collision frequency functions accounting for Brownian motion, laminar and turbulent fluid shear, and differential settling velocity. We implemented the aggregation model in the WRF+FALL3D coupled modelling system and applied it to different eruptions where aggregation has been recognized to play an important role, such as the August and September 1992 Crater Peak eruptions and the 1980 Mt St Helens eruption. Moreover, understanding aggregation processes in volcanic clouds will contribute to mitigate the risks related with volcanic ash transport and sedimentation.

  16. The Earth System Science Pathfinder VOLCAM Volcanic Hazard Mission

    Krueger, Arlin J.


    The VOLCAM mission is planned for research on volcanic eruptions and as a demonstration of a satellite system for measuring the location and density of volcanic eruption clouds for use in mitigating hazards to aircraft by the operational air traffic control systems. A requirement for 15 minute time resolution is met by flight as payloads of opportunity on geostationary satellites. Volcanic sulfur dioxide and ash are detected using techniques that have been developed from polar orbiting TOMS (UV) and AVHRR (IR) data. Seven band UV and three band IR filter wheel cameras are designed for continuous observation of the full disk of the earth with moderate (10 - 20 km) ground resolution. This resolution can be achieved with small, low cost instruments but is adequate for discrimination of ash and sulfur dioxide in the volcanic clouds from meteorological clouds and ozone. The false alarm rate is small through use of sulfur dioxide as a unique tracer of volcanic clouds. The UV band wavelengths are optimized to detect very small sulfur dioxide amounts that are present in pre-eruptive outgassing of volcanoes. The system is also capable of tracking dust and smoke clouds, and will be used to infer winds at tropopause level from the correlation of total ozone with potential vorticity.

  17. Months between rejuvenation and volcanic eruption at Yellowstone caldera, Wyoming

    Till, Christy B.; Vazquez, Jorge A.; Boyce, Jeremy W


    Rejuvenation of previously intruded silicic magma is an important process leading to effusive rhyolite, which is the most common product of volcanism at calderas with protracted histories of eruption and unrest such as Yellowstone, Long Valley, and Valles, USA. Although orders of magnitude smaller in volume than rare caldera-forming super-eruptions, these relatively frequent effusions of rhyolite are comparable to the largest eruptions of the 20th century and pose a considerable volcanic hazard. However, the physical pathway from rejuvenation to eruption of silicic magma is unclear particularly because the time between reheating of a subvolcanic intrusion and eruption is poorly quantified. This study uses geospeedometry of trace element profiles with nanometer resolution in sanidine crystals to reveal that Yellowstone’s most recent volcanic cycle began when remobilization of a near- or sub-solidus silicic magma occurred less than 10 months prior to eruption, following a 220,000 year period of volcanic repose. Our results reveal a geologically rapid timescale for rejuvenation and effusion of ~3 km3 of high-silica rhyolite lava even after protracted cooling of the subvolcanic system, which is consistent with recent physical modeling that predict a timescale of several years or less. Future renewal of rhyolitic volcanism at Yellowstone is likely to require an energetic intrusion of mafic or silicic magma into the shallow subvolcanic reservoir and could rapidly generate an eruptible rhyolite on timescales similar to those documented here.

  18. Structural significance of the south Tyrrhenian volcanism

    Gaudiosi, G.; Musacchio, G.; Ventura, G.; de Astis, G.


    The southern part of the Tyrrhenian Sea represents a transition from ocenic- (the Tyrrhenian Sea) to continental-domain (the Calabrian Arc) and is affected by active calkalkaline to potassic volcanism (the Eolian Islands). Active extensional tectonics, coupled with the general upwelling of northern Sicily and Calabria continental crust, coexists with active subduction of the Ionian Plate beneath the Calabrian Arc. This has been interpreted as the result of the detachment of the slab beneath the Calbrian Arc. Present-day tectonics is characterized by NE-SW normal faults and NNW- SSE dextral oblique-slip faults. The normal faults form the major peri- Tyrrhenian basins. Refraction and high resolution onshore-offshore wide-angle-reflection profiles, as well as potential field modeling, provide a 3D image of the Moho. Short wave-length undulations characterize the Moho beneath the Aeolian Arch. The major upraise is about 6 km, beneath the Aeolian active volcanic area, and affects all the crustal boundaries. Another sharp crustal thinning is observed beneath the gulf of Patti at the south-eastern edge of the Tyrrhenian basin. We suggest that the graben-like structure, occurring along the Salina-Lipari-Vulcano islands and oriented at high angles to the trench, is lithospheric and can be followed down to Moho depths. NNW-SSE dextral oblique-slip faults, like the Tindari Letojanni fault system, control the Salina-Lipari-Vulcano portion of the Aeolian volcanism and connect the oceanic crust of the Marsili Basin to the Malta Escarpment, through the Etna volcano. Across this lineament seismicity changes from mostly shallow to the west, to deep intra- slab to the east.

  19. Philippine protected areas are not meeting the biodiversity coverage and management effectiveness requirements of Aichi Target 11.

    Mallari, Neil Aldrin D; Collar, Nigel J; McGowan, Philip J K; Marsden, Stuart J


    Aichi Target 11 of the Convention on Biological Diversity urges, inter alia, that nations protect at least 17 % of their land, and that protection is effective and targets areas of importance for biodiversity. Five years before reporting on Aichi targets is due, we assessed the Philippines' current protected area system for biodiversity coverage, appropriateness of management regimes and capacity to deliver protection. Although protected estate already covers 11 % of the Philippines' land area, 64 % of its key biodiversity areas (KBAs) remain unprotected. Few protected areas have appropriate management and governance infrastructures, funding streams, management plans and capacity, and a serious mismatch exists between protected area land zonation regimes and conservation needs of key species. For the Philippines to meet the biodiversity coverage and management effectiveness elements of Aichi Target 11, protected area and KBA boundaries should be aligned, management systems reformed to pursue biodiversity-led targets and effective management capacity created.

  20. Soluble iron inputs to the Southern Ocean through recent andesitic to rhyolitic volcanic ash eruptions from the Patagonian Andes

    Simonella, L. E.; Palomeque, M. E.; Croot, P. L.; Stein, A.; Kupczewski, M.; Rosales, A.; Montes, M. L.; Colombo, F.; García, M. G.; Villarosa, G.; Gaiero, D. M.


    Patagonia, due to its geographic position and the dominance of westerly winds, is a key area that contributes to the supply of nutrients to the Southern Ocean, both through mineral dust and through the periodic deposits of volcanic ash. Here we evaluate the characteristics of Fe dissolved (into soluble and colloidal species) from volcanic ash for three recent southern Andes volcanic eruptions having contrasting features and chemical compositions. Contact between cloud waters (wet deposition) and end-members of andesitic (Hudson volcano) and rhyolitic (Chaitén volcano) materials was simulated. Results indicate higher Fe release and faster liberation rates in the andesitic material. Fe release during particle-seawater interaction (dry deposition) has higher rates in rhyolitic-type ashes. Rhyolitic ashes under acidic conditions release Fe in higher amounts and at a slower rate, while in those samples containing mostly glass shards, Fe release was lower and faster. The 2011 Puyehue eruption was observed by a dust monitoring station. Puyehue-type eruptions can contribute soluble Fe to the ocean via dry or wet deposition, nearly reaching the limit required for phytoplankton growth. In contrast, the input of Fe after processing by an acidic eruption plume could raise the amount of dissolved Fe in surface ocean waters several times, above the threshold required to initiate phytoplankton blooms. A single eruption like the Puyehue one represents more than half of the yearly Fe flux contributed by dust.

  1. A Model Simulation of Pinatubo Volcanic Aerosols in the Stratosphere

    Zhao , Jing-xia; Turco, Richard P.; Toon, Owen B.


    A one-dimensional, time-dependent model is used to study the chemical, microphysical, and radiative properties of volcanic aerosols produced by the Mount Pinatubo eruption on June 15, 1991. Our model treats gas-phase sulfur photochemistry, gas-to-particle conversion of sulfur, and the microphysics of sulfate aerosols and ash particles under stratospheric conditions. The dilution and diffusion of the volcanic eruption clouds are also accounted for in these conditions. Heteromolecular homogeneous and heterogeneous binary H2SO4/H2O nucleation, acid and water condensational growth, coagulation, and gravitational sedimentation are treated in detail in the model. Simulations suggested that after several weeks, the volcanic cloud was composed mainly of sulfuric acid/water droplets produced in situ from the SO2 emissions. The large amounts of SO2 (around 20 Mt) injected into the stratosphere by the Pinatubo eruption initiated homogeneous nucleation which generated a high concentration of small H2SO4/H2O droplets. These newly formed particles grew rapidly by condensation and coagulation in the first few months and then reach their stabilized sizes with effective radii in a range between 0.3 and 0.5 micron approximately one-half year after the eruption. The predicted volcanic cloud parameters reasonably agree with measurements in term of the vertical distribution and lifetime of the volcanic aerosols, their basic microphysical structures (e.g., size distribution, concentration, mass ratio, and surface area) and radiative properties. The persistent volcanic aerosols can produce significant anomalies in the radiation field, which have important climatic consequences. The large enhancement in aerosol surface area can result in measurable global stratospheric ozone depletion.

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

    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.

  3. Air Pollution by Hydrothermal Volcanism and Human Pulmonary Function

    Diana Linhares


    Full Text Available The aim of this study was to assess whether chronic exposure to volcanogenic air pollution by hydrothermal soil diffuse degassing is associated with respiratory defects in humans. This study was carried in the archipelago of the Azores, an area with active volcanism located in the Atlantic Ocean where Eurasian, African, and American lithospheric plates meet. A cross-sectional study was performed on a study group of 146 individuals inhabiting an area where volcanic activity is marked by active fumarolic fields and soil degassing (hydrothermal area and a reference group of 359 individuals inhabiting an area without these secondary manifestations of volcanism (nonhydrothermal area. Odds ratio (OR and 95% confidence intervals (CIs were adjusted for age, gender, fatigue, asthma, and smoking. The OR for restrictive defects and for exacerbation of obstructive defects (COPD in the hydrothermal area was 4.4 (95% CI 1.78–10.69 and 3.2 (95% CI 1.82–5.58, respectively. Increased prevalence of restrictions and all COPD severity ranks (mild, moderate, and severe was observed in the population from the hydrothermal area. These findings may assist health officials in advising and keeping up with these populations to prevent and minimize the risk of respiratory diseases.

  4. Volcanic forcing in decadal forecasts

    Ménégoz, Martin; Doblas-Reyes, Francisco; Guemas, Virginie; Asif, Muhammad; Prodhomme, chloe


    Volcanic eruptions can significantly impact the climate system, by injecting large amounts of particles into the stratosphere. By reflecting backward the solar radiation, these particles cool the troposphere, and by absorbing the longwave radiation, they warm the stratosphere. As a consequence of this radiative forcing, the global mean surface temperature can decrease by several tenths of degrees. However, large eruptions are also associated to a complex dynamical response of the climate system that is particularly tricky do understand regarding the low number of available observations. Observations seem to show an increase of the positive phases of the Northern Atlantic Oscillation (NAO) the two winters following large eruptions, associated to positive temperature anomalies over the Eurasian continent. The summers following large eruptions are generally particularly cold, especially over the continents of the Northern Hemisphere. Overall, it is really challenging to forecast the climate response to large eruptions, as it is both modulated by, and superimposed to the climate background conditions, largely driven themselves by internal variability at seasonal to decadal scales. This work describes the additional skill of a forecast system used for seasonal and decadal predictions when it includes observed volcanic forcing over the last decades. An idealized volcanic forcing that could be used for real-time forecasts is also evaluated. This work consists in a base for forecasts that will be performed in the context of the next large volcanic eruption.

  5. Spatial variation of volcanic rock geochemistry in the Virunga Volcanic Province: Statistical analysis of an integrated database

    Barette, Florian; Poppe, Sam; Smets, Benoît; Benbakkar, Mhammed; Kervyn, Matthieu


    We present an integrated, spatially-explicit database of existing geochemical major-element analyses available from (post-) colonial scientific reports, PhD Theses and international publications for the Virunga Volcanic Province, located in the western branch of the East African Rift System. This volcanic province is characterised by alkaline volcanism, including silica-undersaturated, alkaline and potassic lavas. The database contains a total of 908 geochemical analyses of eruptive rocks for the entire volcanic province with a localisation for most samples. A preliminary analysis of the overall consistency of the database, using statistical techniques on sets of geochemical analyses with contrasted analytical methods or dates, demonstrates that the database is consistent. We applied a principal component analysis and cluster analysis on whole-rock major element compositions included in the database to study the spatial variation of the chemical composition of eruptive products in the Virunga Volcanic Province. These statistical analyses identify spatially distributed clusters of eruptive products. The known geochemical contrasts are highlighted by the spatial analysis, such as the unique geochemical signature of Nyiragongo lavas compared to other Virunga lavas, the geochemical heterogeneity of the Bulengo area, and the trachyte flows of Karisimbi volcano. Most importantly, we identified separate clusters of eruptive products which originate from primitive magmatic sources. These lavas of primitive composition are preferentially located along NE-SW inherited rift structures, often at distance from the central Virunga volcanoes. Our results illustrate the relevance of a spatial analysis on integrated geochemical data for a volcanic province, as a complement to classical petrological investigations. This approach indeed helps to characterise geochemical variations within a complex of magmatic systems and to identify specific petrologic and geochemical investigations

  6. Timing and sources of neogene and quaternary volcanism in South-Central Guatemala

    Reynolds, James H.


    Five new and six existing radiometric age dates place constraints on the timing of volcanic episodes in a 1400-km 2 area east of Guatemala City. The source of the voluminous Miocene rhyolitic welded tuffs was the newly discovered Santa Rosa de Lima caldera, in the northern part of the area, not fissure eruptions as was previously believed. Resurgence during the Pliocene included the eruption of more silicic tuffs, followed by post-collapse volcanism around the perimeter. Volcanism in the southern part of the area occurred along the Neogene volcanic front. The sources for these Late Miocene and Pliocene andesitic lavas were not fissure eruptions, as was once believed, but were four large volcanic centers, Cerro Pinula, Ixhuatán, Teanzul, and Cerro La Gabia. The Santa Rosa de Lima caldera structure deflects the Jalpatagua Fault forming tensional fractures along which eruptions in the Quaternary Cuilapa-Barbarena cinder cone field took place. Pleistocene ash flows were erupted from Ixhuatán and Tecuamburro volcanoes in the southern part of the area. Tephras from Ayarza, Amatitlán, and Atitlán blanket the northern and central portions. Present-day activity is restricted to hot springs around the northern and eastern base of Tecuamburro volcano. Based on the work in this area it is proposed that rocks of the Miocene Chalatenango Formation throughout northern Central America were erupted from calderas behind the Neogene volcanic front. Rocks of the Mio-Pliocene Bálsamo Formation in Guatemala and El Salvador were erupted from discrete volcanic centers along the Neogene volcanic front. Pliocene rocks of the Cuscatlán Formation probably represent post-collapse volcanism around earlier caldera structures.

  7. Petrotectonic assemblages and LA-ICP-MS zircon U-Pb age of Early Paleozoic volcanic rocks in Qimantag area, Tibetan Plateau%青藏高原祁漫塔格地区早古生代火山岩岩石构造组合和LA-ICP-MS锆石U-Pb年龄

    王秉璋; 罗照华; 潘彤; 宋泰忠; 校培喜; 张志青


    A study of the Early Paleozoic volcanic rocks in Qimantag area reveals that they were formed in the Middle-Late Ordovi-cian period. The volcanic rocks can be assigned to four volcanic rock belts, i.e., Gonglugou - luanshigou belt, Kuangou - Xi-aolangyashan belt, Bayan Gol-Suhait belt and Naling Gol belt. The first volcanic rock belt belongs to a combination of Nb-enriched basalts characterized by high content of Nb (7.38×10-6-10.1×10-6), TiO2 (1.56%-2.24%) and P2O5 (0.24%-0.34%). The combinations of the volcanic rocks in the second belt are complicated, the SiO2 mass fractions of these rocks are concentrated on two end members, and these rocks can be further divided into two sub-combinations of basalt+basatic andesite and dacite+lithoidite. U-Pb LA-ICP-MS analyses of zircons in basalt and lithoidite yielded the data of 440.2±2.4Ma and 450.3±1.2Ma, respectively. The content of TiO2 (1.1%) and K2O(0.14%) is low while that of Na2O(2.17%) is high for the rocks of the tholeiite combinations in the third belt. Although the content of TiO2 (1.64%) is relatively high, the tholeiite combinations in the fourth belt are very similar to those in the third belt.%祁漫塔格地区早古生代海相火山岩发育,初步确定该地区早古生代海相火山岩的形成时代为中晚奥陶世,可划分出4个火山岩带,分别为公路沟-乱石沟带、宽沟-小狼牙山带、巴音郭勒-苏海图带和那陵格勒河带.公路沟-乱石沟带火山岩为富铌玄武岩组合,具有相对高的Nb(7.4×10-6~10.1×10-6)、TiO2( 1.56%~2.24%)和P2Os(0.24%~0.34%)含量.宽沟-小狼牙山带火山岩岩石类型复杂,SiO2质量分数集中分布于2个端元,可进一步分为玄武岩+玄武安山岩组合和英安岩+流纹岩组合,玄武岩中获得了440.2Ma±2.4Ma的LA-ICP-MS锆石U-Pb年龄值,流纹岩中获得了450.3Ma±1.2Ma的年龄值.巴音郭勒-苏海图带为拉斑玄武岩组合,具低钛(1.1%)、富钠(2.17%,)、低钾(0.14%)的特

  8. Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences

    Goldstein, N.E.; Flexser, S.


    Recent geological and geophysical data for five magma-hydrothermal systems were studied for the purpose of developing estimates for the depth, volume and location of magma beneath each area. The areas studied were: (1) Salton Trough, (2) The Geysers-Clear Lake, (3) Long Valley caldera, (4) Coso volcanic field, and (5) Medicine Lake volcano, all located in California and all selected on the basis of recent volcanic activity and published indications of crustal melt zones. 23 figs.

  9. G-EVER Activities and the Next-generation Volcanic Hazard Assessment System

    Takarada, S.


    The Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) is a consortium of Asia-Pacific geohazard research institutes that was established in 2012. G-EVER aims to formulate strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis and volcanic eruptions. G-EVER is working on enhancing collaboration, sharing of resources, and making information on the risks of earthquakes and volcanic eruptions freely available and understandable. The 1st G-EVER International Symposium was held in Tsukuba, Japan in March 11, 2013. The 2nd Symposium is scheduled in Sendai, Tohoku Japan, in Oct. 19-20, 2013. Currently, 4 working groups were proposed in the G-EVER Consortium. The next-generation volcano hazard assessment WG is developing a useful system for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is based on volcanic eruption history datasets, volcanic eruption database, and numerical simulations. Volcanic eruption histories including precursor phenomena leading to major eruptions of active volcanoes are very important for future prediction of volcanic eruptions. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and types, is important for the next-generation volcano hazard assessment system. Proposing international standards on how to estimate the volume of volcanic products is important to make a high quality volcanic eruption database. Spatial distribution database of volcanic products (e.g. tephra and pyroclastic flow distributions), encoded into a GIS based database is necessary for more precise area and volume estimation and risk assessments. The volcanic eruption database is developed based on past eruption results, which only represents a subset of possible future scenarios. Therefore, numerical simulations with controlled parameters are needed for more precise volcanic eruption

  10. Geophysical surveys of the Joya Honda maar (México) and surroundings; volcanic implications

    López Loera, Héctor; Aranda-Gómez, José Jorge; Arzate, Jorge A.; Molina-Garza, Roberto Stanley


    Joya Honda (JH) is a Quaternary maar excavated in Mesozoic limestone. It is located in central Mexico and belongs to the Ventura volcanic field (VVF), which is composed by cinder cones and maars made of intraplate-type mafic alkalic rocks. Volcanoes in the region form ˜ N20W lineaments, roughly parallel to a regional set of normal faults, but there is no obvious relation between these faults and vent distribution in the exposed geology around the maar. The volcanic rock volume is small in the VVF, and most volcanoes and their products are scattered in a region where outcrops are dominated by limestone. The near-vent tephra associated to the JH maar lies north of the crater. This relation suggests that the crater was formed by directed hydromagmatic explosions and may indicate an inclined volcanic conduit near the surface. The tephra stratigraphy suggests that the initial explosions were relatively dry and the amount of water increased during the maar forming eruption. Therefore, the existing model of the maar-diatreme formation may not be applicable to Joya Honda as it requires the formation of a cone of depression in the aquifer and deepening of the focii of the explosions as the crater and underlying diatreme grew. Thus, it is unlikely that there is a diatreme below Joya Honda. Aeromagnetic data shows a boundary between two regional magnetic domains near the elongated volcanic cluster of the VVF. The boundary is straight, with a distinct kink, from NE- to NW-trend, near JH. The limit between the domains is interpreted as fault contacts between mid-Tertiary volcanic rocks and marine Mesozoic sedimentary rocks. Hence, magma ascent in the area may have been facilitated by fractures near the surface. Magnetic and gravimetric ground surveys show that the anomalies associated with the maar are not centered in the crater, which could be consistent with an inclined volcanic conduit. A magnetic profile measured on exposed limestone across the volcanic lineament failed to

  11. The discovery of Qushenla volcanic rocks in Tasepule area of Nyima Country, Tibet, and its geological significance%西藏尼玛县塔色普勒地区去申拉组火山岩的发现及其地质意义

    吴浩; 李才; 胡培远; 范建军; 张红雨; 李娇


    对塔色普勒地区新发现的去申拉组火山岩进行了系统的地球化学和年龄研究.根据主量元素特征,将区内火山岩划分为富镁安山岩、英安岩和高分异流纹岩3种类型.富镁安山岩具有较高的MgO含量和Mg#值,是俯冲板片熔体与地幔楔相互作用的产物;英安岩与高分异流纹岩具有同源岩浆的特征,富集大离子亲石元素Rb、Th、U、K、Pb,亏损Nb、Ta、Ti、Sr等元素,并具有较高的Rb/Sr值,可能是地壳部分熔融经历了不同分异作用形成的.对流纹岩进行LA-ICP-MS锆石U-Pb定年,获得103Ma±1Ma和107Ma±1Ma的年龄值,显示区内去申拉组火山岩形成于早白垩世晚期.研究认为,区内去申拉组火山岩形成的地球动力学背景是早白垩世晚期班公湖-怒江洋壳向南俯冲过程中发生的板片断离,塔色普勒地区班公湖-怒江洋的陆-陆碰撞时间在107Ma左右.%This paper reports new whole-rock major and trace element data and zircon U-Pb dating results of the newly discovered Qushenla volcanic rocks in Tasepule area,Nyima County,Tibet.According to the features of major elements,the authors grouped volcanic rocks into three types,i.e.,magnesian andesites,dacite and highly differentiated rhyolite.The magnesian andesites produced by the interaction between the subducted slab melt and mantle wedge are rich in MgO and Mg#.Dacite and highly differentiated rhyolites are enriched in Rb,Th,U,K,Pb and depleted in Nb,Ta,Ti,and have high Rb/Sr ratios,which shows that they might be the product of partal melting of the crust which experienced different degrees of differentiation and evolution.The dating of zircons from two rhyolitic samples by LA-ICP-MS yielded ages of 103Ma±-1Ma and 107Ma±1Ma,which indicates that the Qushenla volcanic rocks in the study area were formed in late Early Cretaceous.It is considered that the plate fracturing that happened during the process of southward subduction of Bangong Co-Nujiang Ocean at

  12. Exploratory study on the land area required for global food supply and the potential global production of bioenergy

    Wolf, J.; Bindraban, P.S.; Luijten, J.C.; Vleeshouwers, L.M.


    The areas of agricultural land on this globe that in the future possibly are available for biomass production for energy use and the potential global production of biomass were calculated: These available land areas increased when the global potential for food production (dependent on agricultural s

  13. Widespread effusive volcanism on Mercury likely ended by about 3.5 Ga

    Byrne, Paul K.; Ostrach, Lillian R.; Fassett, Caleb I.; Chapman, Clark R.; Denevi, Brett W.; Evans, Alexander J.; Klimczak, Christian; Banks, Maria E.; Head, James W.; Solomon, Sean C.


    Crater size-frequency analyses have shown that the largest volcanic plains deposits on Mercury were emplaced around 3.7 Ga, as determined with recent model production function chronologies for impact crater formation on that planet. To test the hypothesis that all major smooth plains on Mercury were emplaced by about that time, we determined crater size-frequency distributions for the nine next-largest deposits, which we interpret also as volcanic. Our crater density measurements are consistent with those of the largest areas of smooth plains on the planet. Model ages based on recent crater production rate estimates for Mercury imply that the main phase of plains volcanism on Mercury had ended by ~3.5 Ga, with only small-scale volcanism enduring beyond that time. Cessation of widespread effusive volcanism is attributable to interior cooling and contraction of the innermost planet.

  14. Mantle updrafts and mechanisms of oceanic volcanism

    Anderson, Don L.; Natland, James H.


    Convection in an isolated planet is characterized by narrow downwellings and broad updrafts-consequences of Archimedes' principle, the cooling required by the second law of thermodynamics, and the effect of compression on material properties. A mature cooling planet with a conductive low-viscosity core develops a thick insulating surface boundary layer with a thermal maximum, a subadiabatic interior, and a cooling highly conductive but thin boundary layer above the core. Parts of the surface layer sink into the interior, displacing older, colder material, which is entrained by spreading ridges. Magma characteristics of intraplate volcanoes are derived from within the upper boundary layer. Upper mantle features revealed by seismic tomography and that are apparently related to surface volcanoes are intrinsically broad and are not due to unresolved narrow jets. Their morphology, aspect ratio, inferred ascent rate, and temperature show that they are passively responding to downward fluxes, as appropriate for a cooling planet that is losing more heat through its surface than is being provided from its core or from radioactive heating. Response to doward flux is the inverse of the heat-pipe/mantle-plume mode of planetary cooling. Shear-driven melt extraction from the surface boundary layer explains volcanic provinces such as Yellowstone, Hawaii, and Samoa. Passive upwellings from deeper in the upper mantle feed ridges and near-ridge hotspots, and others interact with the sheared and metasomatized surface layer. Normal plate tectonic processes are responsible both for plate boundary and intraplate swells and volcanism.

  15. Correlation between relative growth rate and specific leaf area requires associations of specific leaf area with nitrogen absorption rate of roots.

    Osone, Yoko; Ishida, Atsushi; Tateno, Masaki


    Close correlations between specific leaf area (SLA) and relative growth rate (RGR) have been reported in many studies. However, theoretically, SLA by itself has small net positive effect on RGR because any increase in SLA inevitably causes a decrease in area-based leaf nitrogen concentration (LNCa), another RGR component. It was hypothesized that, for a correlation between SLA and RGR, SLA needs to be associated with specific nitrogen absorption rate of roots (SAR), which counteracts the negative effect of SLA on LNCa. Five trees and six herbs were grown under optimal conditions and relationships between SAR and RGR components were analyzed using a model based on balanced growth hypothesis. SLA varied 1.9-fold between species. Simulations predicted that, if SAR is not associated with SLA, this variation in SLA would cause a47% decrease in LNCa along the SLA gradient, leading to a marginal net positive effect on RGR. In reality, SAR was positively related to SLA, showing a 3.9-fold variation, which largely compensated for the negative effect of SLA on LNCa. Consequently, LNCa values were almost constant across species and a positive SLA-RGR relationship was achieved. These results highlight the importance of leaf-root interactions in understanding interspecific differences in RGR.

  16. How Volcanism Controls Climate Change

    Ward, P. L.


    Large explosive volcanoes eject megatons of sulfur dioxide into the lower stratosphere where it spreads around the world within months and is oxidized slowly to form a sulfuric-acid aerosol with particle sizes that grow large enough to reflect and scatter solar radiation, cooling Earth ~0.5C for up to 3 years. Explosive eruptions also deplete total column ozone ~6% causing up to 3C winter warming at mid-latitudes over continents. Global cooling predominates. Extrusive, basaltic volcanoes deplete ozone ~6% but do not eject much sulfur dioxide into the lower stratosphere, causing net global warming. Anthropogenic chlorofluorocarbons (CFCs) deplete ozone ~3% for up to a century while each volcanic eruption, even small ones, depletes ozone twice as much but for less than a decade through eruption of halogens and ensuing photochemical processes. The 2010 eruption of Eyjafjallajökull, the 2011 eruption of Grímsvötn, plus anthropogenic CFCs depleted ozone over Toronto Canada 14% in 2012, causing an unusually warm winter and drought. Total column ozone determines how much solar ultraviolet energy with wavelengths between 290 and 340 nanometers reaches Earth where it is absorbed most efficiently by the ocean. A 25% depletion of ozone increases the amount of this radiation reaching Earth by 1 W m-2 for overhead sun and 0.25 W m-2 for a solar zenith angle of 70 degrees. The tropopause is the boundary between the troposphere heated from below by a sun-warmed Earth and the stratosphere heated from above by the Sun through photodissociation primarily of oxygen and ozone. The mean annual height of the tropopause increased ~160 m between 1980 and 2004 at the same time that northern mid-latitude total column ozone was depleted by ~4%, the lower stratosphere cooled ~2C, the upper troposphere warmed ~0.1C, and mean surface temperatures in the northern hemisphere rose ~0.5C. Regional total ozone columns are observed to increase as rapidly as 20% within 5 hours with an associated 5

  17. Hazardous indoor CO2 concentrations in volcanic environments.

    Viveiros, Fátima; Gaspar, João L; Ferreira, Teresa; Silva, Catarina


    Carbon dioxide is one of the main soil gases released silently and permanently in diffuse degassing areas, both in volcanic and non-volcanic zones. In the volcanic islands of the Azores (Portugal) several villages are located over diffuse degassing areas. Lethal indoor CO2 concentrations (higher than 10 vol %) were measured in a shelter located at Furnas village, inside the caldera of the quiescent Furnas Volcano (S. Miguel Island). Hazardous CO2 concentrations were detected not only underground, but also at the ground floor level. Multivariate regression analysis was applied to the CO2 and environmental time series recorded between April 2008 and March 2010 at Furnas village. The results show that about 30% of the indoor CO2 variation is explained by environmental variables, namely barometric pressure, soil water content and wind speed. The highest indoor CO2 concentrations were recorded during bad weather conditions, characterized by low barometric pressure together with rainfall periods and high wind speed. In addition to the spike-like changes observed on the CO2 time series, long-term oscillations were also identified and appeared to represent seasonal variations. In fact, indoor CO2 concentrations were higher during winter period when compared to the dry summer months. Considering the permanent emission of CO2 in various volcanic regions of the world, CO2 hazard maps are crucial and need to be accounted by the land-use planners and authorities.

  18. Guided Dropsonde: Unmanned aerial technology for measuring/sampling volcanic ash plumes in the atmosphere

    Wardell, L. J.; Douglas, J.


    Given the constraints associated with current airborne host platforms, a technological solution is needed for efficiently obtaining in situ atmospheric data/samples at targeted locations and altitudes for hazardous situations such as volcanic ash clouds. Guided dropsondes have significant implications to advance research requiring in situ atmospheric measurements. Compared to conventional free-fall dropsondes that rely on parachutes, guided dropsondes could offer speed controlled descents combined with loiter abilities therefore yielding time averaged data for a particular region-a feature not currently available with existing dropsonde technology. The guided dropsonde's ability to move to targeted areas of interest gains sensors/samplers an unprecedented level of access to extreme areas and events. With flight controls, the guided system can be retrievable as well as deployed from high altitudes. The system to be presented offers additional advantages over conventional UAVs in regards to aviation and technology transfer restrictions and regulations making rapid deployment possible. For large volcanic eruptions this can become a powerful new tool where few options, if any, currently exist to collect in situ data and/or samples. The most recent results from flight tests and evaluations of the guided dropsonde will be presented.

  19. GRID based Thermal Images Processing for volcanic activity monitoring

    Mangiagli, S.; Coco, S.; Drago, L.; Laudani, A.,; Lodato, L.; Pollicino, G.; Torrisi, O.


    Since 2001, the Catania Section of the National Institute of Geophysics and Volcanology (INGV) has been running the video stations recording the volcanic activity of Mount Etna, Stromboli and the Fossa Crater of Vulcano island. The video signals of 11 video cameras (seven operating in the visible band and four in infrared) are sent in real time to INGV Control Centre where they are visualized on monitors and archived on a dedicated NAS storage. The video surveillance of the Sicilian volcanoes, situated near to densely populated areas, helps the volcanologists providing the Civil Protection authorities with updates in real time on the on-going volcanic activity. In particular, five video cameras are operating on Mt. Etna and they record the volcano from the south and east sides 24 hours a day. During emergencies, mobile video stations may also be used to better film the most important phases of the activity. Single shots are published on the Catania Section intranet and internet websites. On June 2006 a A 40 thermal camera was installed in Vulcano La Fossa Crater. The location was in the internal and opposite crater flank (S1), 400 m distant from the fumarole field. The first two-year of data on temperature distribution frequency were recorded with this new methodology of acquisition, and automatically elaborated by software at INGV Catania Section. In fact a dedicated software developed in IDL, denominated Volcano Thermo Analysis (VTA), was appositely developed in order to extract a set of important features, able to characterize with a good approssimation the volcanic activity. In particular the program first load and opportunely convert the thermal images, then according to the Region Of Interest (ROI) and the temperature ranges defined by the user provide to automatic spatial and statistic analysis. In addition the VTA is able to analysis all the temporal series of images available in order to achieve the time-event analysis and the dynamic of the volcanic

  20. Volcanic constructs on Ganymede and Enceladus: Topographic evidence from stereo images and photoclinometry

    Schenk, Paul M.; Moore, Jeffrey M.


    The morphology of volcanic features on Ganymede differs significantly from that on the terrestrial planets. Few if any major volcanic landforms, such as thick flows or shield volcanoes, have been identified to date. Using new stereo Voyager images, we have searched Ganymede for relief-generating volcanic constructs. We observed seven major types of volcanic structures, including several not previously recognized. The oldest are broad flat-topped domes partially filling many older craters in dark terrain. Similar domes occur on Enceladus. Together with smooth dark deposits, these domes indicate that the volcanic history of the dark terrain is complex. Bright terrain covers vast areas, although the style of emplacement remains unclear. Smooth bright materials embay and flood older terrains, and may have been emplaced as low-viscosity fluids. Associated with smooth bright material are a number of scalloped-shaped, semi-enclosed scarps that cut into preexisting terrain. In planform these structures resemble terrestrial calderas. The youngest volcanic materials identified are a series of small flows that may have flooded the floor of the multiring impact structure Gilgamesh, forming a broad dome. The identification of volcanic constructs up to 1 km thick is the first evidence for extrusion of moderate-to-high viscosity material on Ganymede. Viscosity and yield strength estimates for these materials span several orders of magnitude, indicating that volcanic materials on Ganymede have a range of compositions and/or were extruded under a wide range of conditions and/or eruptive styles.

  1. Remote monitoring of volcanic gases using passive Fourier transform spectroscopy

    Love, S.P.; Goff, F.; Counce, D.; Schmidt, S.C. [Los Alamos National Lab., NM (United States); Siebe, C.; Delgado, H. [Univ. Nactional Autonoma de Mexico, Coyoacan (Mexico)


    Volcanic gases provide important insights on the internal workings of volcanoes and changes in their composition and total flux can warn of impending changes in a volcano`s eruptive state. In addition, volcanoes are important contributors to the earth`s atmosphere, and understanding this volcanic contribution is crucial for unraveling the effect of anthropogenic gases on the global climate. Studies of volcanic gases have long relied upon direct in situ sampling, which requires volcanologists to work on-site within a volcanic crater. In recent years, spectroscopic techniques have increasingly been employed to obtain information on volcanic gases from greater distances and thus at reduced risk. These techniques have included UV correlation spectroscopy (Cospec) for SO{sub 2} monitoring, the most widely-used technique, and infrared spectroscopy in a variety of configurations, both open- and closed-path. Francis et al. have demonstrated good results using the sun as the IR source. This solar occultation technique is quite useful, but puts rather strong restrictions on the location of instrument and is thus best suited to more accessible volcanoes. In order to maximize the flexibility and range of FTIR measurements at volcanoes, work over the last few years has emphasized techniques which utilize the strong radiance contrast between the volcanic gas plume and the sky. The authors have successfully employed these techniques at several volcanoes, including the White Island and Ruapehu volcanoes in New Zealand, the Kilauea volcano on Hawaii, and Mt. Etna in Italy. But Popocatepetl (5452 m), the recently re-awakened volcano 70 km southeast of downtown Mexico City, has provided perhaps the best examples to date of the usefulness of these techniques.

  2. Combining long- and short-term probabilistic volcanic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand

    Sandri, Laura; Jolly, Gill; Lindsay, Jan; Howe, Tracy; Marzocchi, Warner


    By using BET_VH, we propose a quantitative probabilistic hazard assessment for base surge impact in Auckland, New Zealand. Base surges resulting from phreatomagmatic eruptions are among the most dangerous phenomena likely to be associated with the initial phase of a future eruption in the Auckland Volcanic Field. The assessment is done both in the long-term and in a specific short-term case study, i.e. the simulated pre-eruptive unrest episode during Exercise Ruaumoko, a national civil defence exercise. The most important factors to account for are the uncertainties in the vent location (expected for a volcanic field) and in the run-out distance of base surges. Here, we propose a statistical model of base surge run-out distance based on deposits from past eruptions in Auckland and in analogous volcanoes. We then combine our hazard assessment with an analysis of the costs and benefits of evacuating people (on a 1 × 1-km cell grid). In addition to stressing the practical importance of a cost-benefit analysis in creating a bridge between volcanologists and decision makers, our study highlights some important points. First, in the Exercise Ruaumoko application, the evacuation call seems to be required as soon as the unrest phase is clear; additionally, the evacuation area is much larger than what is recommended in the current contingency plan. Secondly, the evacuation area changes in size with time, due to a reduction in the uncertainty in the vent location and increase in the probability of eruption. It is the tradeoff between these two factors that dictates which cells must be evacuated, and when, thus determining the ultimate size and shape of the area to be evacuated.

  3. Source mechanisms of volcanic tsunamis.

    Paris, Raphaël


    Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness. © 2015 The Author(s).

  4. Anomalous diffusion of volcanic earthquakes

    Abe, Sumiyoshi


    Volcanic seismicity at Mt. Etna is studied. It is found that the associated stochastic process exhibits a subdiffusive phenomenon. The jump probability distribution well obeys an exponential law, whereas the waiting-time distribution follows a power law in a wide range. Although these results would seem to suggest that the phenomenon could be described by temporally-fractional kinetic theory based on the viewpoint of continuous-time random walks, the exponent of the power-law waiting-time distribution actually lies outside of the range allowed in the theory. In addition, there exists the aging phenomenon in the event-time averaged mean squared displacement, in contrast to the picture of fractional Brownian motion. Comments are also made on possible relevances of random walks on fractals as well as nonlinear kinetics. Thus, problems of volcanic seismicity are highly challenging for science of complex systems.

  5. Contribution of ground surface altitude difference to thermal anomaly detection using satellite images: Application to volcanic/geothermal complexes in the Andes of Central Chile

    Gutiérrez, Francisco J.; Lemus, Martín; Parada, Miguel A.; Benavente, Oscar M.; Aguilera, Felipe A.


    Detection of thermal anomalies in volcanic-geothermal areas using remote sensing methodologies requires the subtraction of temperatures, not provided by geothermal manifestations (e.g. hot springs, fumaroles, active craters), from satellite image kinetic temperature, which is assumed to correspond to the ground surface temperature. Temperatures that have been subtracted in current models include those derived from the atmospheric transmittance, reflectance of the Earth's surface (albedo), topography effect, thermal inertia and geographic position effect. We propose a model that includes a new parameter (K) that accounts for the variation of temperature with ground surface altitude difference in areas where steep relief exists. The proposed model was developed and applied, using ASTER satellite images, in two Andean volcanic/geothermal complexes (Descabezado Grande-Cerro Azul Volcanic Complex and Planchón-Peteroa-Azufre Volcanic Complex) where field data of atmosphere and ground surface temperature as well as radiation for albedo calibration were obtained in 10 selected sites. The study area was divided into three zones (Northern, Central and Southern zones) where the thermal anomalies were obtained independently. K value calculated for night images of the three zones are better constrained and resulted to be very similar to the Environmental Lapse Rate (ELR) determined for a stable atmosphere (ELR > 7 °C/km). Using the proposed model, numerous thermal anomalies in areas of ≥ 90 m × 90 m were identified that were successfully cross-checked in the field. Night images provide more reliable information for thermal anomaly detection than day images because they record higher temperature contrast between geothermal areas and its surroundings and correspond to more stable atmospheric condition at the time of image acquisition.

  6. Local to global: a collaborative approach to volcanic risk assessment

    Calder, Eliza; Loughlin, Sue; Barsotti, Sara; Bonadonna, Costanza; Jenkins, Susanna


    Volcanic risk assessments at all scales present challenges related to the multitude of volcanic hazards, data gaps (hazards and vulnerability in particular), model representation and resources. Volcanic hazards include lahars, pyroclastic density currents, lava flows, tephra fall, ballistics, gas dispersal and also earthquakes, debris avalanches, tsunamis and more ... they can occur in different combinations and interact in different ways throughout the unrest, eruption and post-eruption period. Volcanoes and volcanic hazards also interact with other natural hazards (e.g. intense rainfall). Currently many hazards assessments consider the hazards from a single volcano but at national to regional scales the potential impacts of multiple volcanoes over time become important. The hazards that have the greatest tendency to affect large areas up to global scale are those transported in the atmosphere: volcanic particles and gases. Volcanic ash dispersal has the greatest potential to directly or indirectly affect the largest number of people worldwide, it is currently the only volcanic hazard for which a global assessment exists. The quantitative framework used (primarily at a regional scale) considers the hazard at a given location from any volcano. Flow hazards such as lahars and floods can have devastating impacts tens of kilometres from a source volcano and lahars can be devastating decades after an eruption has ended. Quantitative assessment of impacts is increasingly undertaken after eruptions to identify thresholds for damage and reduced functionality. Some hazards such as lava flows could be considered binary (totally destructive) but others (e.g. ash fall) have varying degrees of impact. Such assessments are needed to enhance available impact and vulnerability data. Currently, most studies focus on physical vulnerability but there is a growing emphasis on social vulnerability showing that it is highly variable and dynamic with pre-eruption socio

  7. Volcanic mercury in Pinus canariensis

    Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis


    Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg-1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg-1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg-1) and bark (6.0 μg kg-1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

  8. Volcanic risk perception in the Vesuvius population

    Barberi, F.; Davis, M. S.; Isaia, R.; Nave, R.; Ricci, T.


    A volcanic risk perception study of the population residing near Vesuvius was carried out between May and July, 2006. A total of 3600 questionnaires with 45 items were distributed to students, their parents and the general population. The largest number of surveys (2812) were distributed in the 18 towns of the Red Zone, the area nearest to the volcano that is exposed to pyroclastic flow hazards and whose 550,000 residents, according to the civil protection emergency plan (in operation since 1995), should be evacuated in case of an eruption crisis. The remaining 788 questionnaires were distributed in 3 additional towns and 3 neighborhoods of Naples, all within the Yellow Zone, which is an area exposed to pyroclastic fallout hazards. A total of 2655 surveys were returned, resulting in a response rate of 73.7%. Results indicated that people have a realistic view of the risk: they think that an eruption is likely, that it will have serious consequences for their towns and for themselves and their families and they are quite worried about the threat. However, several other social, economic, and security-related issues were listed as a problem more often than Vesuvius. The study also demonstrated a widespread lack of knowledge about the emergency plan, a lack of confidence in the plan's success and in public officials and low feelings of self-efficacy. People want to be more deeply involved in public discussions with scientists and civil protection officials on emergency planning and individual preparedness measures. It is clear from the results that a major education-information effort is still needed to improve the public's knowledge, confidence and self-efficacy, thereby improving their collective and individual capability to positively face a future volcanic emergency.

  9. 50 CFR Table 20 to Part 679 - Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679...


    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Seabird Avoidance Gear Requirements for Vessels, based on Area, Gear, and Vessel Type. (See § 679.24(e) for complete seabird avoidance program...) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Table 20 Table 20 to Part 679—Seabird...

  10. 23 CFR Appendix G to Subpart A of... - Special Reporting Requirements for “Hometown” or “Imposed” Plan Areas


    ... 23 Highways 1 2010-04-01 2010-04-01 false Special Reporting Requirements for âHometownâ or âImposedâ Plan Areas G Appendix G to Subpart A of Part 230 Highways FEDERAL HIGHWAY ADMINISTRATION... Federal-Aid Construction Contracts (Including Supportive Services) Pt. 230, Subpt. A, App. G Appendix G...

  11. Calderas and mineralization: volcanic geology and mineralization in the Chianti caldera complex, Trans-Pecos Texas

    Duex, T.W.; Henry, C.D.


    This report describes preliminary results of an ongoing study of the volcanic stratigraphy, caldera activity, and known and potential mineralization of the Chinati Mountains area of Trans-Pecos Texas. Many ore deposits are spatially associated with calderas and other volcanic centers. A genetic relationship between calderas and base and precious metal mineralization has been proposed by some and denied by others. Steven and others have demonstrated that calderas provide an important setting for mineralization in the San Juan volcanic field of Colorado. Mineralization is not found in all calderas but is apparently restricted to calderas that had complex, postsubsidence igneous activity. A comparison of volcanic setting, volcanic history, caldera evolution, and evidence of mineralization in Trans-Pecos to those of the San Juan volcanic field, a major mineral producer, indicates that Trans-Pecos Texas also could be an important mineralized region. The Chianti caldera complex in Trans-Pecos Texas contains at least two calderas that have had considerable postsubsidence activity and that display large areas of hydrothermal alteration and mineralization. Abundant prospects in Trans-Pecos and numerous producing mines immediately south of the Trans-Pecos volcanic field in Mexico are additional evidence that ore-grade deposits could occur in Texas.

  12. Aeromagnetic Study of Tke Huichapan Caldera; Central Volcanic Belt

    Gonzalez, T.; Martin, A.; Alfaro, G.; Oyarzabal, E.


    Analysis of the aeromagnetic anomalies over the central sector of the Mexican Volcanic Belt sheds new light on the structure of the Huichapan Caldera. This volcanic center located 100 Km to the north- northwest of Mexico City is approximately 10 km in diameter and related to an ignimbrite sequence. Milan et al, (1993) and. Aguirre-Diaz and Lopez-Martinez (2009) mapped Huichapan area and described the geology and petrology of the erupted products in the region. Aguirre-Diaz and Lopez-Martinez (2009) suggest the idea of two overlapping calderas related to an ignimbrite sequence. The analyzed region is a rectangular area, approximately from 20.25 N to 20.42 N and between 99.42 W and 99.6 W. The total field aeromagnetic data was obtained with a Geometrics G-803 proton magnetometer at a flight altitude of 300 m above ground level. For the analysis of the anomalies, the data was further smoothed to construct a 1 km regularly spaced grid. The anomaly map was compared with the surface geology and larger anomalies were correlated with major volcanic features. Since our main interest was in mapping the subsurface intrusive and volcanic bodies, the total field magnetic anomalies were reduced to the pole by using the double integral Fourier method. The reduced to the pole anomaly map results in a simplified pattern of isolated positive and negative anomalies, which show an improved correlation with all major volcanic structures. For the analysis and interpretation of the anomalies, the reduced to the pole anomalies were continued upward at various reference levels. These operations result in smoothing of the anomaly field by the filtering of high frequency anomalies that may be related to shallow sources. Two profiles were selected that cross the major anomalies on the Huichapan Caldera. The Talwani algorithm for 2-D polygonal bodies has been used for calculating the theoretical anomalies.

  13. Spatio-temporal evolution of the Tuxtla Volcanic Field

    Kobs Nawotniak, S. E.; Espindola, J.; Godinez, L.


    Mapping of the Tuxtla Volcanic Field (TVF), located in Veracruz, Mexico, through the use of digital elevation models, aerial photography, and field confirmation has found 353 distinct cones, 4 large composite volcanoes, and 42 maars. Eruptive activity in the TVF began in the late Miocene, underwent a quiescent period approximately 2.6-0.8 Ma, and continues into historic times with the most recent eruption occurring at San Martín Tuxtla volcano in 1793. The covariance of the minimum cone separation in the TVF indicates that, despite the influence of clear vent alignments following regional faulting trends, the field as a whole is anticlustered. Dividing the cones by morphometric age shows that while the older cones have an anti-clustered distribution, the younger cones (Catemaco. These areas of concentrated volcanism roughly correspond to the locations of two gravity anomalies previously identified in the area. While the average height/width ratio is equal between the two clusters, the cones in the eastern group are significantly smaller than their counterparts in the western group. The maars of the TVF are mostly located within the younger volcanic series, west of Laguna Catemaco, and have an anticlustered distribution; many of the maars are evenly spaced along curved lines, where they are weakly grouped according to crater diameter. Results indicate volcanism TVF has undergone continued spatial restriction over time, concentrating in the western half of the TVF with the onset of the eruption of the younger volcanic series 0.8 Ma and further contracting along the principle fault system within the last 50 Ka.

  14. Frequent underwater volcanism in the central Aegean Sea

    Huebscher, C.; Ruhnau, M.; Dehghani, G. A.


    The extinction of the Minoan culture in the mid second millennium BCE is a well known consequence of the Plinian eruption of Thera volcano (Santorini Island). Santorini is a member of the South Aegean arc forming a chain from the Gulf of Saronikos (Susaki, Egina, Poros, Methana) at West, to an area close to the Anatolian coast at East (Kos, Nisyros and minor islands), through the central part (Milos and Santorini island groups). Underwater volcanic activity was manifested historically only once. During 1649-1650 CE the Kolumbo underwater volcano evolved about 8 km northeast of Santorini. As a consequence of this eruption volcanic ash covered the entire Aegean area and a hazardous tsunami was triggered. Here we show by means of reflection seismic and magnetic data that underwater volcanism occurred more frequently in the central Aegean Sea than previously assumed. Seismic data show that Kolumbo constitutes of five vertically stacked cones of pyroclastic sediment plus at least four smaller cones on the flank of the volcano. The formation of Kolumbo started synchronous with Santorini Island. The entire volume of the Kolumbo pyroclastic cones is estimated to more than 15 cubic-kilometers. Several small-scale cones have been detected in the Anyhdros Basin some km north-east of Kolumbo, being previously interpreted as mud volcanoes by other authors. However, the similarity of seismic and magnetic signatures of these cones and Kolumbo strongly suggest that these cones were also created by underwater volcanism. Volcanic cones, Kolumbo and Santorini are situated along a NE-SW striking graben system that evolved during five extensional tectonic pulses in the Pliocene.

  15. The Requirement for Vocational Skills in the Engineering Industry in the Areas of Modena and Vienna. Synthesis Report.

    Gatti, Mario; Mereu, Maria Grazia; Tagliaferro, Claudio; Markowitsch, Jorg; Neuberger, Robert

    Requirements for vocational skills in the engineering industry in Modena, Italy, and Vienna, Austria, were studied. In Modena, employees of a representative sample of 90 small, medium, and large firms in the mechanical processing, agricultural machinery, and sports car manufacturing sectors were interviewed. In Vienna, data were collected through…

  16. Database for potential hazards from future volcanic eruptions in California

    White, Melissa N.; Ramsey, David W.; Miller, C. Dan


    More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the past 10,000 yr. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Sooner or later, volcanoes in California will erupt again, and they could have serious impacts on the health and safety of the State's citizens as well as on its economy. This report describes the nature and probable distribution of potentially hazardous volcanic phenomena and their threat to people and property. It includes hazard-zonation maps that show areas relatively likely to be affected by future eruptions in California. This digital release contains information from maps of potential hazards from future volcanic eruptions in the state of California, published as Plate 1 in U.S. Geological Survey Bulletin 1847. The main component of this digital release is a spatial database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, main report text, and accompanying hazard tables from Bulletin 1847. It should be noted that much has been learned about the ages of eruptive events in the State of California since the publication of Bulletin 1847 in 1989. For the most up to date information on the status of California volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

  17. Status of volcanic hazard studies for the Nevada Nuclear Waste Storage Investigations. Volume II

    Crowe, B.M.; Wohletz, K.H.; Vaniman, D.T.; Gladney, E.; Bower, N.


    Volcanic hazard investigations during FY 1984 focused on five topics: the emplacement mechanism of shallow basalt intrusions, geochemical trends through time for volcanic fields of the Death Valley-Pancake Range volcanic zone, the possibility of bimodal basalt-rhyolite volcanism, the age and process of enrichment for incompatible elements in young basalts of the Nevada Test Site (NTS) region, and the possibility of hydrovolcanic activity. The stress regime of Yucca Mountain may favor formation of shallow basalt intrusions. However, combined field and drill-hole studies suggest shallow basalt intrusions are rare in the geologic record of the southern Great Basin. The geochemical patterns of basaltic volcanism through time in the NTS region provide no evidence for evolution toward a large-volume volcanic field or increases in future rates of volcanism. Existing data are consistent with a declining volcanic system comparable to the late stages of the southern Death Valley volcanic field. The hazards of bimodal volcanism in this area are judged to be low. The source of a 6-Myr pumice discovered in alluvial deposits of Crater Flat has not been found. Geochemical studies show that the enrichment of trace elements in the younger rift basalts must be related to an enrichment of their mantle source rocks. This geochemical enrichment event, which may have been metasomatic alteration, predates the basalts of the silicic episode and is, therefore, not a young event. Studies of crater dimensions of hydrovolcanic landforms indicate that the worst case scenario (exhumation of a repository at Yucca Mountain by hydrovolcanic explosions) is unlikely. Theoretical models of melt-water vapor explosions, particularly the thermal detonation model, suggest hydrovolcanic explosion are possible at Yucca Mountain. 80 refs., 21 figs., 5 tabs.

  18. Estimation of the Required Amount of Hydrological Exploration in Lignite Mining Areas on the Basis of Hypothetical Hydrogeological Models

    Kaden, S.; Reichel, F.; Luckner, L.


    Mine drainage is a necessary but very costly precaution for open-pit lignite mining in sandy aquifers. Consequently, the minimization of the number of drainage wells and their optimal operation become important tasks in designing mine drainage systems. Comprehensive groundwater flow models have to be used, both, for the design of drainage wells, and for the analysis of water management strategies in mining areas . The accuracy of computations with such models depends on the precision of the u...

  19. Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey

    Deligne, Natalia I.; Mckay, Daniele; Conrey, Richard M.; Grant, Gordon E.; Johnson, Emily R.; O'Connor, Jim; Sweeney, Kristin


    The Cascade Range in central Oregon has been shaped by tectonics, volcanism, and hydrology, as well as geomorphic forces that include glaciations. As a result of the rich interplay between these forces, mafic volcanism here can have surprising manifestations, which include relatively large tephra footprints and extensive lava flows, as well as water shortages, transportation and agricultural disruption, and forest fires. Although the focus of this multidisciplinary field trip will be on mafic volcanism, we will also look at the hydrology, geomorphology, and ecology of the area, and we will examine how these elements both influence and are influenced by mafic volcanism. We will see mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. In addition, this field trip will occur during a total solar eclipse, the first one visible in the United States in more than 25 years (and the first seen in the conterminous United States in more than 37 years).The Cascade Range is the result of subduction of the Juan de Fuca plate underneath the North American plate. This north-south-trending volcanic mountain range is immediately downwind of the Pacific Ocean, a huge source of moisture. As moisture is blown eastward from the Pacific on prevailing winds, it encounters the Cascade Range in Oregon, and the resulting orographic lift and corresponding rain shadow is one of the strongest precipitation gradients in the conterminous United States. We will see how the products of the volcanoes in the central Oregon Cascades have had a profound influence on groundwater flow and, thus, on the distribution of Pacific moisture. We will also see the influence that mafic volcanism has had on landscape evolution, vegetation development, and general hydrology.

  20. Quantitative physical models of volcanic phenomena for hazards assessment of critical infrastructures

    Costa, Antonio


    Volcanic hazards may have destructive effects on economy, transport, and natural environments at both local and regional scale. Hazardous phenomena include pyroclastic density currents, tephra fall, gas emissions, lava flows, debris flows and avalanches, and lahars. Volcanic hazards assessment is based on available information to characterize potential volcanic sources in the region of interest and to determine whether specific volcanic phenomena might reach a given site. Volcanic hazards assessment is focussed on estimating the distances that volcanic phenomena could travel from potential sources and their intensity at the considered site. Epistemic and aleatory uncertainties strongly affect the resulting hazards assessment. Within the context of critical infrastructures, volcanic eruptions are rare natural events that can create severe hazards. In addition to being rare events, evidence of many past volcanic eruptions is poorly preserved in the geologic record. The models used for describing the impact of volcanic phenomena generally represent a range of model complexities, from simplified physics based conceptual models to highly coupled thermo fluid dynamical approaches. Modelling approaches represent a hierarchy of complexity, which reflects increasing requirements for well characterized data in order to produce a broader range of output information. In selecting models for the hazard analysis related to a specific phenomenon, questions that need to be answered by the models must be carefully considered. Independently of the model, the final hazards assessment strongly depends on input derived from detailed volcanological investigations, such as mapping and stratigraphic correlations. For each phenomenon, an overview of currently available approaches for the evaluation of future hazards will be presented with the aim to provide a foundation for future work in developing an international consensus on volcanic hazards assessment methods.

  1. The United States national volcanic ash operations plan for aviation

    Albersheim, Steven; Guffanti, Marianne


    Volcanic-ash clouds are a known hazard to aviation, requiring that aircraft be warned away from ash-contaminated airspace. The exposure of aviation to potential hazards from volcanoes in the United States is significant. In support of existing interagency operations to detect and track volcanic-ash clouds, the United States has prepared a National Volcanic Ash Operations Plan for Aviation to strengthen the warning process in its airspace. The US National Plan documents the responsibilities, communication protocols, and prescribed hazard messages of the Federal Aviation Administration, National Oceanic and Atmospheric Administration, US Geological Survey, and Air Force Weather Agency. The plan introduces a new message format, a Volcano Observatory Notice for Aviation, to provide clear, concise information about volcanic activity, including precursory unrest, to air-traffic controllers (for use in Notices to Airmen) and other aviation users. The plan is online at While the plan provides general operational practices, it remains the responsibility of the federal agencies involved to implement the described procedures through orders, directives, etc. Since the plan mirrors global guidelines of the International Civil Aviation Organization, it also provides an example that could be adapted by other countries.

  2. Exploring Volcanism with Digital Technology in Undergraduate Education

    McCoy, F. W.; Parisky, A.


    Volcanism as one of the most dynamic geological processes on this planet is also one of the most dramatic for attracting students to the earth sciences. At the University of Hawaii (UH) volcanism is used to attract students into the geosciences, coupled with its significant association to Hawaiian culture and contemporary issues such as those associated with related hazards - example: during the past century five towns were buried by lava flows on the Big Island, another recently threatened with destruction. To bring this dynamism into undergraduate education, UH focuses on field trips and courses to all islands; at Windward Community College (WCC/UH) a focus is provided through a series of field courses (1 credit) to all islands, especially the Big Island. Critical to the WCC effort are computer-generated animations and descriptions of volcanological processes for illustrating concepts undergraduate students find difficult: tumescence as an indicator of an eruption, fractional crystallization, collapse of volcanic edifices, explosive eruptions, weathering processes, hazards and mitigation, all embedded in the evolutionary story of mid-ocean volcanic islands such as those in Hawaii. Field courses require intense field labs, which are significantly assisted by digital platforms that include computer-generated illustrations, descriptions, animations, and more. The consequence for developing geoscientists has been outstanding.

  3. Cleopatra Patera on Venus: Venera 15/16 evidence for a volcanic origin.

    Schaber, G.G.; Kozak, R.C.; Masursky, H.


    The non-concentric nature, anomalous depth, and terraced morphology of the nested craters that compose Cleopatra Patera are more closely analogous to volcanic craters (calderas) than multi-ring impact structures. Associated deposits northeast and downslope of the Patera first recognized on Venera 15/16 radar images are interpreted as volcanic plains related to, and perhaps cogenetic with, Cleopatra. A volcanic origin not only is easily reconciled with the tectonic setting of the Patera, it is almost required by the correlation between the Patera and regional structural trend. -from Authors

  4. Geochemistry and tectonic setting of Permian volcanic rocks in Yingen-Ejin Banner basin and its neighboring areas, western Inner Mongolia%内蒙古西部银根-额济纳旗盆地及邻区二叠纪火山岩的地球化学特征和构造环境

    党犇; 赵虹; 林广春; 仵康林; 康晓燕; 葛海影; 吴斌; 刘少红


    Permian volcanic rocks are widespread in Yingen-Ejin Banner basin and its neighboring areas, and their genesis and tectonic setting remain a problem of much controversy. Based on a petrologic and geochemical analysis of Permian volcanic rocks in the study area, this paper attempts to clarify the palaeo-tectonic setting and provides independent evidence for understanding the nature of the basin. The volcanic rocks are dominated by basalts, basaltic-andesite and andesite, which fall into the sub-alkaline series. Mg# content of this suite ranges from 0.53 to 0.86, exhibiting strong depletion of the high field strength elements Nb, Ta and Ti and slight enrichment of LREE. In terms of REE, (La/Yb)N content ranges from 1.68 to 6.10, showing insignificant Eu depletion (δEu=0.64~0.99)and slightly right-oblique REE distribution patterns. These data show not only the characteristics of an intraplate setting on the whole but also the signature of a subduction zone. Combined with the sedmentary formation characteristics, the authors have reached the conclusion that the Permian magmatic activity of the study area was generated in an intraplate setting, with variable degrees of contamination of the crust during magmatic ascending, related probably to the mantle plume event.%银-额(银根-额济纳旗)盆地及其邻区二叠纪火山岩分布广泛,目前对其成因和构造背景研究还很薄弱.对该区火山岩岩石学和元素地球化学特征进行研究,为恢复二叠纪盆地性质与古构造环境提供了岩石地球化学约束.分析的二叠纪火山岩主要岩石类型为玄武岩、玄武安山岩和安山岩,显示亚碱性系列的特征.Mg#介于0.5~0.86之间,高场强元素Nb、Ta、Ti明显亏损,岩石轻度富集轻稀土元素(LREE),(La/Yb)N=1.68~6.10,Eu亏损不明显(δEu=0.64~0.99),稀土元素配分曲线右倾较缓.总体上既显示了板内构造环境的特征,又具有俯冲带地球化学的印记.综合沉积建造特征和

  5. Planetary Aspects of Volcanism: Insights Into the Volcano - Tectonic Relationship on Earth

    Cañón-Tapia, E.


    There are many alternative definitions of a volcanic system, each focusing on different aspects of volcanic and/or magmatic activity. Although all of these definitions contribute to increase our understanding of volcanic phenomena, each was conceived with a specific aspect of volcanism in mind, therefore reducing its utility when problems beyond its own limits are considered, and perhaps more importantly, introducing subtle biases in the form in which we approach the study of this type of phenomena. In particular, the volcano-tectonic relationship most commonly used in volcanology textbooks seems to be biased towards volcanic activity on Earth, disregarding the presence of this type of phenomena in other planets, moons and even asteroids of our solar system. As a cursory examination of volcanism in the solar system reveals, the causes of volcanic activity deserve to be examined independently of any tectonic influence. Any model of volcanism of this type, however, needs to be flexible enough to accommodate tectonic variables if so required. In this work, such a flexible model of volcanism is outlined. This model is constructed by first exploring the form in which the Tectonic and the Volcanic systems are related to each other in different planets by using a mechanical analogy. Second, the analogy is used to identify key components of the volcanic system that need to be quantified first, therefore leading to the introduction of fundamental physical principles in the conceptual model of volcanism that is independent of the tectonic scenario. Third, the predictive capabilities of this model are compared to specific cases on Earth where the type of required information has been gathered previously. The results suggest that the physical constraints of the model are reasonable, therefore paving the road for further studies aiming to identify the tectonic contribution of volcanism on a case by case basis. Two corollaries of this study are that we need to learn to formulate

  6. Mount Rainier: learning to live with volcanic risk

    Driedger, C.L.; Scott, K.M.


    Mount Rainier in Washington state is an active volcano reaching more than 2.7 miles (14,410 feet) above sea level. Its majestic edifice looms over expanding suburbs in the valleys that lead to nearby Puget Sound. USGS research over the last several decades indicates that Mount Rainier has been the source of many volcanic mudflows (lahars) that buried areas now densely populated. Now the USGS is working cooperatively with local communities to help people live more safely with the volcano.

  7. Paleomagnetic data from the Trans-Mexican Volcanic Belt: implications for tectonics and volcanic stratigraphy

    Alva-Valdivia, L. M.; Goguitchaichvili, A.; Ferrari, L.; Rosas-Elguera, J.; Urrutia-Fucugauchi, J.; Zamorano-Orozco, J. J.


    We report a paleomagnetic and rock-magnetic study of Miocene volcanic rocks from the Trans-Mexican Volcanic Belt. A total of 32 sites (238 oriented samples) were collected from three localities: Queretaro, Guadalajara and Los Altos de Jalisco basaltic plateaux, which span from 11 to 7.5 Ma. Several rock-magnetic experiments were carried out in order to identify the magnetic carriers and to obtain information about their paleomagnetic stability. Microscopic observation of polished sections shows that the main magnetic mineral is Ti-poor titanomagnetite associated with exsolved ilmenite. Continuous susceptibility measurements with temperature yield in most cases reasonably reversible curves with Curie points close to that of magnetite. Judging from the ratios of hysteresis parameters, it seems that all samples fall in the pseudo-single domain (PSD) grain size region, probably indicating a mixture of multidomain (MD) and a significant amount of single domain (SD) grains. Based on our paleomagnetic and available radiometric data, it seems that the volcanic units have been emplaced during a relatively short time span of 1 to 2 My at each locality. The mean paleomagnetic directions obtained from each locality differ significantly from that expected for the Middle Miocene. The mean paleomagnetic direction calculated from 28 sites discarding those of intermediate polarity is I= 32.46°, D= 341.2°, k= 7.2 and a95= 11.6°. Comparison with the expected direction indicates some 20° anticlockwise tectonic rotations for the studied area, in accordance with the proposed left-lateral transtensional tectonic regime already proposed for this period.

  8. Geology of Volcan Las Navajas, a pleistocene trachyte/peralkaline rhyolite volcanic center in Nayarit, Mexico

    Hegre, J.A.; Nelson, S.A.


    Volcan Las Navajas, located in the northwestern portion of the Mexican Volcanic Belt has produced a sequence of volcanic rocks with compositions in marked contrast to the predominantly calc-alkaline volcanoes which predominate in this part of Mexico. The oldest exposed lavas consist of trachytes with 63% SiO/sub 2/, 6% FeO*, and 500 ppm Zr along with comenditic rhyolites with 68% SiO/sub 2/, 5% FeO*, 800 ppm Zr, and an agpaitic index of 1.0. These lavas were followed by the eruption of a comenditic ash-flow tuff and the formation of a caldera 2.7 km in diameter. This caldera was subsequently filled by eruptions of pantelleritic rhyolite obsidian lava flows with 72% SiO/sub 2/, 8% FeO*, 1100 ppm Zr, and an agpaitic index of 1.5 to 1.9. A second caldera was then formed which is offset to the south of the main eruptive vents for previous eruptions. This younger caldera has a diameter of about 4.8 km and its southern walls have been covered by calc-alkaline andesitic lavas erupted from nearby Sanganguey volcano. Volcanoclastic sediments in the floor of the younger caldera have been tilted and faulted in a manner suggestive of late stage resurgence. Subsequent eruptions within the caldera, however, have been restricted to calc-alkaline andesites. Tectonically, the area in which this volcano occurs appears to have been undergoing a crustal rifting event since the Pliocene. The occurrence of these peralkaline rocks lends further support to such a hypothesis.

  9. Precursory volcanic CO2 signals from space

    Schwandner, Florian M.; Carn, Simon A.; Kataoka, Fumie; Kuze, Akihiko; Shiomi, Kei; Goto, Naoki


    through emission plumes, providing momentary cross sections. While GOSAT measured approximately circular ~10.5km diameter single-shot footprints, OCO-2 can provide hundreds more soundings per area at single kilometer scale footprint resolution. In this contribution, we summarize the approach and progress made over the past 5 years of CO2 satellite observations, and their application toward detecting volcanic CO2 eruption precursors. © California Institute of Technology

  10. Characterization of fine volcanic ash from explosive eruption from Sakurajima volcano, South Japan

    Nanayama, F.; Furukawa, R.; Ishizuka, Y.; Yamamoto, T.; Geshi, N.; Oishi, M.


    Explosive volcanic eruptions can affect infrastructure and ecosystem by their dispersion of the volcanic particle. Characterization of volcanic particle expelled by explosive eruption is crucial for evaluating for quantitative hazard assessment by future volcanic eruption. Especially for fine volcanic ash less than 64 micron in diameter, it can disperse vast area from the source volcano and be easily remobilized by surface wind and precipitation after the deposition. As fine volcanic ash is not preserved well at the earth surface and in strata except for enormously large scale volcanic eruption. In order to quantify quantitative characteristics of fine volcanic ash particle, we sampled volcanic ash directly falling from the eruption cloud from Showa crater, the most active vent of Sakurajima volcano, just before landing on ground. We newly adopted high precision digital microscope and particle grain size analyzer to develop hazard evaluation method of fine volcanic ash particle. Field survey was performed 5 sequential days in January, 2013 to take tamper-proof volcanic ash samples directly obtained from the eruption cloud of the Saku