Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity.

PubMed

Urbieta, María Sofía; Porati, Graciana Willis; Segretín, Ana Belén; González-Toril, Elena; Giaveno, María Alejandra; Donati, Edgardo Rubén

2015-07-08

The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.

Fractionation of elements by particle size of ashes ejected from Copahue Volcano, Argentina.

PubMed

Gómez, Dario; Smichowski, Patricia; Polla, Griselda; Ledesma, Ariel; Resnizky, Sara; Rosa, Susana

2002-12-01

The volcano Copahue, Neuquén province, Argentina has shown infrequent explosive eruptions since the 18th century. Recently, eruptive activity and seismicity were registered in the period July-October, 2000. As a consequence, ash clouds were dispersed by winds and affected Caviahue village located at about 9 km east of the volcano. Samples of deposited particles from this area were collected during this episode for their chemical analysis to determine elements of concern with respect to the health of the local population and its environment. Different techniques were used to evaluate the distribution of elements in four particle size ranges from 36 to 300 microm. X-ray powder diffraction (XRD) was selected to detect major components namely, minerals, silicate glass, fragments of rocks and sulfurs. Major and minor elements (Al, Ca, Cl, Fe, K, Mg, Mn, Na, S, Si and Ti), were detected by energy dispersive X ray analysis (EDAX). Trace element (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, U, V and Zn) content was quantified by inductively coupled plasma-mass spectrometry (ICP-MS). Nuclear activation analysis (NAA) was employed for the determination of Ce, Co, Cs, Eu, Hf, La, Lu, Rb, Sc, Sm, Ta and Yb. An enrichment was observed in the smallest size fraction of volcanic ashes for four elements (As, Cd, Cu and Sb) of particular interest from the environmental and human health point of view.

Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity

PubMed Central

Urbieta, María Sofía; Willis Porati, Graciana; Segretín, Ana Belén; González-Toril, Elena; Giaveno, María Alejandra; Donati, Edgardo Rubén

2015-01-01

The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea. PMID:27682093

Electric structure of the Copahue Volcano (Neuquén Province, Argentina), from magnetotelluric soundings: 1D and 2D modellings

NASA Astrophysics Data System (ADS)

Mamaní, M. J.; Borzotta, E.; Venencia, J. E.; Maidana, A.; Moyano, C. E.; Castiglione, B.

2000-05-01

Four magnetotelluric soundings were carried out in 1993 in the region of the Copahue active volcano located at the border between Chile and Argentina (37°45'S, 71°18'W). Three soundings were located inside the caldera of the ancient stratovolcano (east of Copahue) and the fourth outside it. The soundings inside the caldera were situated at about 6, 11, and 14 km from the volcano. Digital data were obtained covering the range of periods from 1 sec to 10,000 sec using induction coils and a flux-gate magnetometer to obtain the magnetic data and Cu-SO 4Cu electrodes for electric field measurements. The apparent resistivity curves corresponding to principal directions were analyzed in conjunction with the geological background in order to eliminate distortion — which is very important in this hot volcanic region. Then, 1D modellings were performed using the "normal" curves — i.e., curves without distortions. Using the apparent resistivity curves with distortions, 2D modelling was also performed along a profile perpendicular to the regional tectonic trend suggested by MT soundings into the caldera. Results show low resistivity values of about 3-15 Ωm between 9 km to 20 km depth in the crust, suggesting high temperatures, with minimum values of about 700°C with partially melted zones in the upper crust between 9 km to 20 km depth under the caldera. The presence of a possible sulphide-carbonaceous layer (SC layer) in the upper basement could play an important role in lowering the electrical resistivities because of its high electronic conductivity.

Magma evolution at Copahue volcano (Chile/Argentina border): insights from melt inclusions

NASA Astrophysics Data System (ADS)

Cannatelli, C.; Aracena, C.; Leisen, M.; Moncada, D.; Roulleau, E.; Vinet, N.; Petrelli, M.; Paolillo, A.; Barra, F.; Morata, D.

2016-12-01

Copahue volcano is an active stratovolcano in the Andean Southern Volcanic Zone (SVZ), straddling at the border between Central Chile and Argentina. The volcano's eruptive style during its history has changed from mainly effusive in the Pleistocene to explosive in the Holocene. The prehistoric eruptions can be divided into pre-glacial (PG), syn-glacial (SG) and post-glacial (PM) stages, with products ranging from basaltic andesites to andesites. In order to investigate the evolution of the magma source and volatiles through time, we have focused our study on the eruptive products from the SG to the 2014 eruption (SUM2014). Sampled rocks are glomero-porphyritic, with a paragenetic mineral sequence of feldspars, ortho- and clinopyroxene, and olivine in order of abundance. All samples present a variable number of vesicles, with SUM2014 samples containing the biggest amount. Feldspar composition varies from Na-rich (andesine) in SG to Ca-rich (labradorite) in SUM2014. Two pyroxene types are present in SG and PM samples (augite and enstatite), while SUM2014 presents augite, pigeonite and enstatite. Thermobarometric estimation, based on mineral chemistry, show a bimodal distribution for SG and SUM2014 (P=10-12 kbars and 5-8 kbars) and only one interval for PM (P=7-8 kbars). Melt Inclusions Assemblages (MIAs) are found in all mineral phases, mostly re-crystallized, with one or more bubbles and daughter oxide minerals. Compositions vary from trachy-andesitic to dacitic for SG, andesitic to trachydacitic for PM, and basaltic andesitic to trachydacitic for SUM2014. Major elements systematics show the existence of a bimodal distribution of pyroxene and feldspar hosted-MIA in SUM2014, which together with the co-presence of pigeonite (low-Ca pyroxene) and augite and the bimodal distribution of P, can be interpreted as evidence of mixing of two types of magmas, evolving at different depths. Trace elements systematics for MIA in SG, PM and SUM2014 show a negative anomaly for Nb

Acid fluids from Copahue Volcano, Argentina, and their environmental effects

NASA Astrophysics Data System (ADS)

Varekamp, J. C.; Kading, T.

2010-12-01

The acid hydrothermal system of Copahue volcano (province of Neuquen, Argentina) consists of a crater lake, acid hot springs (both with pH values of <1 to 2) and a severely acidified fluvial-lake system, with the voluminous Lake Caviahue (0.5 km3; pH 2.2 - 3). Annual measurements of river water fluxes and water compositions and vertical lake water profiles provide a 12 year record of geochemical evolution of the system. Copahue erupted in 2000, and the hydrothermal dissolved element fluxes peaked at that time. Since 2001, the K and Al fluxes have decreased notably as a result of alunite saturation within the hydrothermal system, whereas over the last few years redissolution of that alunite has led to increases in K and Al discharges. The fluxes of Mg and Fe have remained high over time, while the overall system has become more dilute since 2000. Once the distal downstream system reached pH values of 2.9-3.2, the mineral Schwertmannite started to precipitate through a bacterially mediated pathway. The precipitation front gradually moved upstream with ongoing dilution, and reached the exit of Lake Caviahue in 2009. The lake bottom waters were already saturated with the mineral at that time, and if this trend continues, the currently clear blue lake may turn into a bright yellow-brown mass of Schwertmannite over the next few years. Schwertmannite is common in acid mine drainage fluids but has not often been described from volcanic environments. It strongly adsorbs oxyanions (or structurally incorporates them) and the precipitates contain up to 6000 ppm P, 1100 ppm V and 1000 ppm As. The Schwertmannite appears to convert to goethite-like minerals over time, although the exact stoichiometry has been difficult to constrain (variable mixtures of FeOOH and Fe8O8(OH)6SO4 nH2O). The oxyanions appear to remain in the mineral mix during aging. If Lake Caviahue becomes a focus of Schwertmannite deposition, the precipitates will scavenge As, P and V from the watercolumn and

Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuquén, Argentina

PubMed Central

Yaakop, Amira Suriaty; Chan, Chia Sing; Urbieta, M. Sofía; Ee, Robson; Tan-Guan-Sheng, Adrian; Donati, Edgardo R.

2016-01-01

Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment. PMID:27540078

Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuquén, Argentina.

PubMed

Willis Poratti, Graciana; Yaakop, Amira Suriaty; Chan, Chia Sing; Urbieta, M Sofía; Chan, Kok-Gan; Ee, Robson; Tan-Guan-Sheng, Adrian; Goh, Kian Mau; Donati, Edgardo R

2016-08-18

Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment. Copyright © 2016 Willis Poratti et al.

Investigating crater lake warming using ASTER thermal imagery: Case studies at Ruapehu, Poás, Kawah Ijen, and Copahué Volcanoes

NASA Astrophysics Data System (ADS)

Trunk, Laura; Bernard, Alain

2008-12-01

A two-channel or split-window algorithm designed to correct for atmospheric conditions was applied to thermal images taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) of Lake Yugama on Kusatsu-Shirane volcano in Japan in order to measure the temperature of its crater lake. These temperature calculations were validated using lake water temperatures that were collected on the ground. Overall, the agreement between the temperatures calculated using the split-window method and ground truth is quite good, typically ± 1.5 °C for cloud-free images. Data from fieldwork undertaken in the summer of 2004 at Kusatsu-Shirane allow a comparison of ground-truth data with the radiant temperatures measured using ASTER imagery. Further images were analyzed of Ruapehu, Poás, Kawah Ijen, and Copahué volcanoes to acquire time-series of lake temperatures. A total of 64 images of these 4 volcanoes covering a wide range of geographical locations and climates were analyzed. Results of the split-window algorithm applied to ASTER images are reliable for monitoring thermal changes in active volcanic lakes. These temperature data, when considered in conjunction with traditional volcano monitoring techniques, lead to a better understanding of whether and how thermal changes in crater lakes aid in eruption forecasting.

Hyperacid volcano-hydrothermal fluids from Copahue volcano, Argentina: Analogs for "subduction zone fluids"?

NASA Astrophysics Data System (ADS)

Varekamp, J. C.

2007-12-01

Hyperacid concentrated Chlorine-Sulfate brines occur in many young arc volcanoes, with pH values <1, high concentrations of volcanogenic elements (S, Cl, F, As, B) and the main rock forming elements (Ca, Al, Mg, K, Na, P). Sulfur isotope data and Silica thermometry from such fluids sampled over a ten year period from the Copahue volcanic system (Argentina) suggest reservoir temperatures of 175-300 oC, whereas the surface fluids do not exceed local boiling temperatures. These fluids are generated at much lower P-T conditions than fluids associated with a dehydrating subducted sediment complex below arc volcanoes, but their fundamental chemical compositions may have similarities. Incompatible trace element, major element concentrations and Pb isotope compositions of the fluids were used to determine the most likely rock protoliths for these fluids. Mean rock- normalized trace element diagrams then indicate which elements are quantitatively extracted from the rocks and which are left behind or precipitated in secondary phases. Most LILE show flat rock-normalized patterns, indicating close to congruent dissolution, whereas Ta-Nb-Ti show strong depletions in the rock-normalized diagrams. These HFSE are either left behind in the altered rock protolith or were precipitated along the way up. The behavior of U and Th is almost identical, suggesting that in these low pH fluids with abundant ligands Th is just as easily transported as U, which is not the case in more dilute, neutral fluids. Most analyzed fluids have steeper LREE patterns than the rocks and have negative Eu anomalies similar to the rocks. Fluids that interacted with newly intruded magma e.g., during the 2000 eruption, have much less pronounced Eu anomalies, which was most likely caused by the preferential dissolution of plagioclase when newly intruded magma interacted with the acid fluids. The fluids show a strong positive correlation between Y and Cd (similar to MORB basalts, Yi et al., JGR, 2000), suggesting

Earthquake-induced static stress change on magma pathway in promoting the 2012 Copahue eruption

NASA Astrophysics Data System (ADS)

Bonali, F. L.

2013-11-01

It was studied how tectonic earthquake-induced static stress changes could have contributed to favouring the 22 December 2012 major eruption at Copahue volcano, Chile. Numerical modelling indicates that the vertical N60°E-striking magma pathway below Copahue was affected by a normal stress reduction induced by the Mw 8.8 Chile earthquake of 27 February 2010. A sensitivity analysis suggests that N-, NE- and E-striking vertical planes are affected by normal stress decrease (maximum at the NE-striking plane), and that also a possible inclined N60°E plane is affected by this reduction. Copahue did not have any magmatic event since 2000. Seismic signals of awakening started in April 2012 and the first volcanic event occurred on July 2012. Thus, it is here suggested a possible earthquake-induced feedback effect on the crust below the volcanic arc up to at least 3 years after a large subduction earthquake, favouring new eruptions.

The 2012-2016 eruptive cycle at Copahue volcano (Argentina) versus the peripheral gas manifestations: hints from the chemical and isotopic features of fumarolic fluids

NASA Astrophysics Data System (ADS)

Tassi, F.; Agusto, M.; Lamberti, C.; Caselli, A. T.; Pecoraino, G.; Caponi, C.; Szentiványi, J.; Venturi, S.; Vaselli, O.

2017-10-01

This study presents the chemical and isotopic compositions of hydrothermal gases from fumaroles discharging around Copahue volcano (Argentina). Gas samples, including those from two fumaroles at the active summit crater, were collected during 13 surveys carried out by different research teams from 1976 to February 2016. The time-series of H2, CO and light hydrocarbons showed episodic increases related to the main events of the last eruptive cycle that started on 19 July 2012. Concentration peaks were likely caused by enhanced input of hot magmatic fluids affecting the hydrothermal reservoir. These data contrast with the temporal variations shown by Rc/ Ra and δ13C-CO2 values in 2012-2014, which indicated an increasing input from a crustal fluid source. In 2015-2016, however, these isotopic parameters showed opposite trends; their composition became closer to that of the two summit fumaroles, which possibly corresponds to that of the deep magmatic-related end-member. The delayed and reduced compositional changes in the peripheral hydrothermal fluid discharge in response to the 2012-2016 eruptive events suggest that geochemical surveys of these emissions are unlikely to provide premonitory signals of volcanic unrest if the volcanic activity remains centered in the main crater. Instead, an instrument which is able to provide measurements of volcanic gases in the air (e.g. MultiGAS) may be used to detect changes at the summit crater. Otherwise, monitoring of seismic activity and ground deformation, as well as the periodic measurement of the chemistry of the water in the Rio Agrio, which is fed by thermal discharge from the summit crater, seem to represent the most reliable means of monitoring at Copahue. However, the relative compositional stability of the hydrothermal reservoir is a great advantage in terms of geothermal resource exploitation and could encourage new investments in the Copahue geothermal project which was abandoned in the 1990s.

Petrology of the 1995/2000 Magma of Copahue, Argentina

NASA Astrophysics Data System (ADS)

Goss, A.; Varekamp, J. C.

2001-05-01

Phreatomagmatic eruptions of Copahue in July/August,1995 and July/August 2000 produced mixed juvenile clasts, silica-rich debris from the hydrothermal system, and magmatic scoria with 88 percent SiO2. These high-SiO2 clasts carry an as yet unidentified (crystobalite?), euhedral silica phase in great abundance, which is riddled with tan, primary melt inclusions. The mixed clasts have bands of mafic material with small euhedral olivine, clinopyroxene, and plagioclase that are mixed with an intermediate magma with coarser, resorbed phenocrysts of olivine, plagioclase, clino- and ortho- pyroxene, and rare occurrences of the silica phase. These ejecta are intimate mixtures of a relatively felsic magma similar to Pleistocene Copahue lavas and a mafic basaltic andesite, with minor contributions of a magma contaminated with silica-rich hydrothermal wallrock material. Two-pyroxene geothermometry indicates crystallization temperatures of 1020 deg - 1045 deg C. Glass inclusions (59-63 percent SiO2) in plagioclase and olivine crystals yield very low volatile contents in the melt (0.4-1.5 percent H2O). The 1995/2000 magmas resided at shallow level and degassed into the active volcano-hydrothermal system which discharges acid fluids into the Copahue crater lake and hot springs. More mafic magma intruded this shallow batch and the mixture rose into the hydrothermal system and assimilated siliceous wall rock. A Ti-diffusion profile in a magnetite crystal suggests that the period between magma mixing and eruption was on the order of 4-10 weeks, and the temperature difference between resident and intruding magma was about 50-60 oC.

Spatial Distribution of b-value of the Copahue volcano during 2012-2014 eruptive period: Relationship between magmatic and hydrothermal system

NASA Astrophysics Data System (ADS)

Lazo, Jonathan; Basualto, Daniel; Bengoa, Cintia; Cardona, Carlos; Franco, Luis; Gil-Cruz, Fernando; Hernández, Erasmo; Lara, Luis; Lundgren, Paul; Medina, Roxana; Morales, Sergio; Peña, Paola; Quijada, Jonathan; Samsonov, Sergey; San Martin, Juan; Valderrama, Oscar

2015-04-01

Temporal and spatial variations of b-value have been interpreted as regional stress changes on active tectonic zones or magma ascent and/or hydrothermal fluids mobilization that could affect to active volcanic arc. Increasing of fluids pressure, medium heterogeneities or temperature changes would be the cause of these variations. The Copahue volcano is a shield strato-volcano that has been edified on the western margin of the Caviahue Caldera, located in the international border between Chile and Argentina, which contain an important geothermic field and is located at a horse-tail structure of the Liquiñe-Ofqui Fault Zone. The pre-fracture nature of its basement, as well as an extensive geothermic field, would be producing very complex conditions to fluids movement that could be exploring to use the 'b' value of the recorded seismicity between 2012 and 2014. Based in the database of VT seismic events, we used 2.073 events to calculate the b-value to obtain the 2D and 3D distribution maps. Results showed two anomalous zones: the first one located 9 Km to NE of the active crater, 3-6 Km depth, with high b-values (>1.2) that is associated with a very high production rate of small earthquakes that could suggest a brittle zone, located in the active geothermal field. The second zone, showed a low b-values (~ 0.7), located to east of the volcano edifice at <3 Km depth, associated to a zone where were generated larger magnitude events, suggesting a zone with more stress accumulation that well correlated with the deformation center detected by InSAR measurements. This zone could be interpreted as the magmatic source that interacts with the shallow hydrothermal system. Thus, in a very complex setting as a volcano sitting on top of a geothermal system, the b-value offers a tool to understand the distribution of the seismic sources and hence a physical constrain for the coupled magmatic/hydrothermal system.

Seismic unrest at Katla Volcano- southern Iceland

NASA Astrophysics Data System (ADS)

jeddi, zeinab; Tryggvason, Ari; Gudmundsson, Olafur; Bödvarsson, Reynir; SIL Seismology Group

2014-05-01

Katla volcano is located on the propagating Eastern Volcanic Zone (EVZ) in South Iceland. It is located beneath Mýrdalsjökull ice-cap which covers an area of almost 600 km2, comprising the summit caldera and the eruption vents. 20 eruptions between 930 and 1918 with intervals of 13-95 years are documented at Katla which is one of the most active subglacial volcanoes in Iceland. Eruptions at Katla are mainly explosive due to the subglacial mode of extrusion and produce high eruption columns and catastrophic melt water floods (jökulhlaups). The present long Volcanic repose (almost 96 years) at Katla, the general unrest since 1955, and the 2010 eruption of the neighbouring Eyjafjallajökull volcano has prompted concerns among geoscientists about an imminent eruption. Thus, the volcano has been densely monitored by seismologists and volcanologists. The seismology group of Uppsala University as a partner in the Volcano Anatomy (VA) project in collaboration with the University of Iceland and the Icelandic Meteorological Office (IMO) installed 9 temporary seismic stations on and around the Mýrdalsjökull glacier in 2011. Another 10 permanent seismic stations are operated by IMO around Katla. The project's data collection is now finished and temporary stations were pulled down in August 2013. According to seismicity maps of the whole recording period, thousands of microearthquakes have occurred within the caldera region. At least three different source areas are active in Katla: the caldera region, the western Godaland region and a small cluster at the southern rim of Mýrdalsjökull near the glacial stream of Hafursarjökull. Seismicity in the southern flank has basically started after June 2011. The caldera events are mainly volcano-tectonic, while western and southern events are mostly long period (lp) and can be related to glacial or magmatic movement. One motivation of the VA Katla project is to better understand the physical mechanism of these lp events. Changes

Comparison of the microbial communities of hot springs waters and the microbial biofilms in the acidic geothermal area of Copahue (Neuquén, Argentina).

PubMed

Urbieta, María Sofía; González-Toril, Elena; Bazán, Ángeles Aguilera; Giaveno, María Alejandra; Donati, Edgardo

2015-03-01

Copahue is a natural geothermal field (Neuquén province, Argentina) dominated by the Copahue volcano. As a consequence of the sustained volcanic activity, Copahue presents many acidic pools, hot springs and solfataras with different temperature and pH conditions that influence their microbial diversity. The occurrence of microbial biofilms was observed on the surrounding rocks and the borders of the ponds, where water movements and thermal activity are less intense. Microbial biofilms are particular ecological niches within geothermal environments; they present different geochemical conditions from that found in the water of the ponds and hot springs which is reflected in different microbial community structure. The aim of this study is to compare microbial community diversity in the water of ponds and hot springs and in microbial biofilms in the Copahue geothermal field, with particular emphasis on Cyanobacteria and other photosynthetic species that have not been detected before in Copahue. In this study, we report the presence of Cyanobacteria, Chloroflexi and chloroplasts of eukaryotes in the microbial biofilms not detected in the water of the ponds. On the other hand, acidophilic bacteria, the predominant species in the water of moderate temperature ponds, are almost absent in the microbial biofilms in spite of having in some cases similar temperature conditions. Species affiliated with Sulfolobales in the Archaea domain are the predominant microorganism in high temperature ponds and were also detected in the microbial biofilms.

Calbuco Volcano Erupts in Southern Chile

NASA Image and Video Library

2015-04-24

Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS

The 2012 Copahue eruption: magnitude of gas fluxes and time scale of degassing

NASA Astrophysics Data System (ADS)

Varekamp, J. C.; Camfield, L.

2015-12-01

Copahue volcano (Argentina, 37.5 S, 71.5 W) erupted in 2000 and 2012 with initial phreato-magmatic blasts, violent Strombolian eruptions of several hours duration, followed by open conduit activity for days to months. The 2012 basal deposits 10 km S of Copahue are mm-sized ashes with hydrothermally altered debris, followed by up to 10cm pancake pumices, while denser cinders fell near the crater in the waning stages. The strombolian plume was ~ 6 km high and satellite images show its trajectory up to 200 km S. The pumices have finely porous rims (0.3mm vesicles) that were probably quenched by hydrothermal fluids and coarse interiors (several mm vesicles) that inflated during eruption. All the products have identical chemical composition and mineralogy, and only vary in degree of vesiculation. The 2012 products are the most mafic of the whole volcanic history of Copahue, with MgO ~ 4.5 %. The quench rim pumice glass contains 1160 ppm Cl while glass inclusions have up to 1800 ppm Cl. Water concentrations are 0.5-2.0 % (by difference with EMPA) and plagioclase hygrometry. Pre-eruptive conditions were 1080 oC and 1-2.5 kb pressure. The magmato-hydrothermal system is leaking fluids into the overlying crater lake and into a river. The hot springs have pH <1 and these fluids are up to 60% magmatic in origin. Annual river flux measurements and non-steady state modeling between 1997 and 2013 constrain the mean hydrothermal Cl flux at 1170 tonnes/month. The 2012 erupted magma mass is about 1012 gr, and from the measured total Cl loss between 2000 and 2012 and mean degassed Cl in the magma the volume of degassing magma is estimated at 1014-1015 grams. Much more magma was degassing than was erupted. Analyses of 226Ra-210Pb constrained the maximum degassing time at 8-10 years prior to the 2012 eruption. Almost all rock samples have 210Pb deficits, and so most gas escaped from the magma into the hydrothermal system. Nonetheless, the top of the magma reservoir accumulated bubbles

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Shallow magmatic degassing into the hydrothermal system of Copahue, Argentina

NASA Astrophysics Data System (ADS)

Varekamp, J.; Ouimette, A.; Kreulen, R.; Delpino, D.; Bermudez, A.

2001-05-01

Copahue volcano has a crater lake and acid hot springs that discharge into the Rio Agrio river system. These fluids are very concentrated (up to 6 percent sulfate), rich in rock-forming elements (up to 2000 ppm Mg) and small spheres of native sulfur float in the crater lake. The stable isotope composition of the waters (delta 18O =-2.1 to + 3.6 per mille; delta D = -49 to -26 per mille) indicates that the hot spring waters are at their most concentrated about 70 percent volcanic brine and 30 percent glacial meltwater. The crater lake waters have similar mixing proportions but added isotope effects from intense evaporation. Further dilution of the waters in the Rio Agrio gives values closer to local meteoric waters (delta 18O = -11 per mille; delta D = -77 per mille), whereas evaporation in closed ponds led to very heavy water (up to delta 18O = +12 per mille). The delta 34S value of dissolved sulfate is +14.2 per mille, whereas the native sulfur has values of -8.2 to -10.5 per mille. The heavy sulfate probably formed when SO2 disproportionated into bisulfate and native sulfur. We measured the sulfate fluxes in the Rio Agrio, and from these flux values and the stoichiometry of the disproportionation reaction we calculated the rate of liquid sulfur storage inside the volcano (6000 m3/year). During the eruptions of 1995/2000, large amounts of that stored liquid sulfur were ejected as pyroclastic sulfur. The calculated rate of rock dissolution (from rock- forming element fluxes in the Rio Agrio) suggests that the void space generated by rock dissolution is largely filled by native sulfur. The isotopic signature of the magmatic sulfur can be reconstituted at about +7 per mille, which is a source signature with superposed effects of shallow degassing. Lead isotope and 129Iodine data from the fluids indicate that subducted components may have played a role in the Copahue magma formation. Primary glass inclusions in plagioclase and olivine have 1110-1670 ppm Cl, 90-400 ppm

Eruptive history and tectonic setting of Medicine Lake Volcano, a large rear-arc volcano in the southern Cascades

USGS Publications Warehouse

Donnelly-Nolan, J. M.; Grove, T.L.; Lanphere, M.A.; Champion, D.E.; Ramsey, D.W.

2008-01-01

Medicine Lake Volcano (MLV), located in the southern Cascades ??? 55??km east-northeast of contemporaneous Mount Shasta, has been found by exploratory geothermal drilling to have a surprisingly silicic core mantled by mafic lavas. This unexpected result is very different from the long-held view derived from previous mapping of exposed geology that MLV is a dominantly basaltic shield volcano. Detailed mapping shows that < 6% of the ??? 2000??km2 of mapped MLV lavas on this southern Cascade Range shield-shaped edifice are rhyolitic and dacitic, but drill holes on the edifice penetrated more than 30% silicic lava. Argon dating yields ages in the range ??? 475 to 300??ka for early rhyolites. Dates on the stratigraphically lowest mafic lavas at MLV fall into this time frame as well, indicating that volcanism at MLV began about half a million years ago. Mafic compositions apparently did not dominate until ??? 300??ka. Rhyolite eruptions were scarce post-300??ka until late Holocene time. However, a dacite episode at ??? 200 to ??? 180??ka included the volcano's only ash-flow tuff, which was erupted from within the summit caldera. At ??? 100??ka, compositionally distinctive high-Na andesite and minor dacite built most of the present caldera rim. Eruption of these lavas was followed soon after by several large basalt flows, such that the combined area covered by eruptions between 100??ka and postglacial time amounts to nearly two-thirds of the volcano's area. Postglacial eruptive activity was strongly episodic and also covered a disproportionate amount of area. The volcano has erupted 9 times in the past 5200??years, one of the highest rates of late Holocene eruptive activity in the Cascades. Estimated volume of MLV is ??? 600??km3, giving an overall effusion rate of ??? 1.2??km3 per thousand years, although the rate for the past 100??kyr may be only half that. During much of the volcano's history, both dry HAOT (high-alumina olivine tholeiite) and hydrous calcalkaline

Arsenic speciation and trace element analysis of the volcanic río Agrio and the geothermal waters of Copahue, Argentina.

PubMed

Farnfield, Hannah R; Marcilla, Andrea L; Ward, Neil I

2012-09-01

Surface water originating from the Copahue volcano crater-lake was analysed for total arsenic and four arsenic species: arsenite (iAs(III)), arsenate (iAs(V)), monomethylarsonic acid (MA(V)) and dimethylarsinic acid (DMA(V)) and other trace elements (Fe, Mn, V, Cr, Ni, Zn). A novel in-field technique for the preconcentration and separation of four arsenic species was, for the first time, used for the analysis of geothermal and volcanic waters. Total arsenic levels along the río Agrio ranged from <0.2-3783 μg/l As(T). The highest arsenic levels were recorded in the el Vertedero spring (3783 μg/l As(T)) on the flank of the Copahue volcano, which feeds the acidic río Agrio. Arsenite (H(3)AsO(3)) predominated along the upper río Agrio (78.9-81.2% iAs(III)) but the species distribution changed at lago Caviahue and arsenate (H(2)AsO(4)(-)) became the main species (51.4-61.4% iAs(V)) up until Salto del Agrio. The change in arsenic species is potentially a result of an increase in redox potential and the formation of iron-based precipitates. Arsenic speciation showed a statistically significant correlation with redox potential (r=0.9697, P=0.01). Both total arsenic and arsenic speciation displayed a statistically significant correlation with vanadium levels along the river (r=0.9961, P=0.01 and r=0.8488, P=0.05, respectively). This study highlights that chemical speciation analysis of volcanic waters is important in providing ideas on potential chemical toxicity. Furthermore there is a need for further work evaluating how arsenic (and other trace elements), released in volcanic and geothermal streams/vents, impacts on both biota and humans (via exposure in thermal pools or consuming commercial drinking water). Copyright © 2012 Elsevier B.V. All rights reserved.

Calbuco Volcano Erupts in Southern Chile

NASA Image and Video Library

2015-04-24

Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS Credit: NOAA/NASA GOES Project NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Volcanism at Hualca Hualca Volcano, Southern Peru

NASA Astrophysics Data System (ADS)

Burkett, B.

2005-12-01

Nevado Hualca Hualca (6025m), in southern Peru, is the northernmost edifice in a north-south trending chain of 3 volcanoes that includes Ampato and the active Sabancaya stratovolcano. The oldest in the chain and considered extinct, virtually no research exists about the history of this large volcano. The summit of the volcano shows deep incision by glaciation, which from aerial photographs appears unaffected by later volcanism. Its north slope, however, possesses numerous volcanic domes, extensive lava flows with distinct levees and transverse ridges, and pyroclastic flow deposits. Deposits on the northwestern slope of Hualca Hualca include breadcrust-rich block-and-ash flows (BAF), several dacite lava flows including one with an identifiable source dome about 15km from the summit, and a sequence of small pyroclastic flow deposits with minor associated tephra. Analyses of these deposits show a restricted range of compositions (63-68 wt% SiO2). The PF sequence has an upward decrease in SiO2 and basaltic andesite (56 wt% SiO2) inclusions occur in the uppermost PFs. Principal phenocrysts include plagioclase, biotite, hornblende, clinopyroxene, orthopyroxene, Fe-Ti oxides, and sphene. Fine grained, angular to sub-rounded magmatic enclaves occur within the breadcrust-rich BAF deposits and the youngest lava flow. They are characterized by randomly oriented acicular hornblende, lack of chilled margins, and a few voids indicative of a quench texture. Plagioclase crystals with "dusty" rims or cores present in most of the deposits suggest resorption caused by magma recharge. These features imply a stratified magma chamber subject to magma recharge events and mingling to produce the quench texture enclaves. Chemical analyses indicate that the volcanic products result from magma mixing processes; the basaltic andesite inclusions may represent the mafic end-member of the mixing process. The physical characteristics of the deposits and chemical analyses were compared with data

The geothermal system of Caviahue-Copahue Volcanic Complex (Chile-Argentina): New insights from self-potential, soil CO2 degassing, temperature measurements and helium isotopes, with structural and fluid circulation implications.

NASA Astrophysics Data System (ADS)

Roulleau, Emilie; Bravo, Francisco; Barde-Cabusson, Stephanie; Pizarro, Marcela; Muños, Carlos; Sanchez, Juan; Tardani, Daniele; Sano, Yuji; Takahata, Naoto; de Cal, Federico; Esteban, Carlos

2016-04-01

Geothermal systems represent natural heat transfer engines in a confined volume of rock which are strongly influenced by the regional volcano-tectonic setting controlling the formation of shallow magmatic reservoirs, and by the local faults/fracture network, that permits the development of hydrothermal circulation cells and promote the vertical migration of fluids and heat. In the Southern Volcanic Zone of Chile-Argentina, geothermal resources occur in close spatial relationship with active volcanism along the Cordillera which is primarily controlled by the 1000 km long, NNE Liquiñe-Ofqui Fault Zone (LOFZ), an intra-arc dextral strike-slip fault system, associated with second-order intra-arc anisotropy of overall NE-SW (extensional) and NW-SE orientation (compressional). However there is still a lack of information on how fault network (NE and WNW strinking faults) and lithology control the fluid circulation. In this study, we propose new data of dense self-potential (SP), soil CO2 emanation and temperature (T) measurements within the geothermal area from Caviahue-Copahue Volcanic Complex (CCVC), coupled with helium isotopes ratios measured in fumaroles and thermal springs. We observe that inside the geothermal system the NE-striking faults, characterized by a combination of SP-CO2 and T maxima with high 3He/4He ratios (7.86Ra), promote the formation of high vertical permeability pathways for fluid circulation. Whereas, the WNW-striking faults represent low permeability pathways for hydrothermal fluids ascent associated with moderate 3He/4He ratios (5.34Ra), promoting the infiltration of meteoric water at shallow depth. These active zones are interspersed by SP-CO2- T minima, which represent self-sealed zones (e.g. impermeable altered rocks) at depth, creating a barrier inhibiting fluids rise. The NE-striking faults seem to be associated with the upflow zones of the geothermal system, where the boiling process produces a high vapor-dominated zone close to the

Unzipping of the volcano arc, Japan

USGS Publications Warehouse

Stern, R.J.; Smoot, N.C.; Rubin, M.

1984-01-01

A working hypothesis for the recent evolution of the southern Volcano Arc, Japan, is presented which calls upon a northward-progressing sundering of the arc in response to a northward-propagating back-arc basin extensional regime. This model appears to explain several localized and recent changes in the tectonic and magrnatic evolution of the Volcano Arc. Most important among these changes is the unusual composition of Iwo Jima volcanic rocks. This contrasts with normal arc tholeiites typical of the rest of the Izu-Volcano-Mariana and other primitive arcs in having alkaline tendencies, high concentrations of light REE and other incompatible elements, and relatively high silica contents. In spite of such fractionated characteristics, these lavas appear to be very early manifestations of a new volcanic and tectonic cycle in the southern Volcano Arc. These alkaline characteristics and indications of strong regional uplift are consistent with the recent development of an early stage of inter-arc basin rifting in the southern Volcano Arc. New bathymetric data are presented in support of this model which indicate: 1. (1) structural elements of the Mariana Trough extend north to the southern Volcano Arc. 2. (2) both the Mariana Trough and frontal arc shoal rapidly northwards as the Volcano Arc is approached. 3. (3) rugged bathymetry associated with the rifted Mariana Trough is replaced just south of Iwo Jima by the development of a huge dome (50-75 km diameter) centered around Iwo Jima. Such uplifted domes are the immediate precursors of rifts in other environments, and it appears that a similar situation may now exist in the southern Volcano Arc. The present distribution of unrifted Volcano Arc to the north and rifted Mariana Arc to the south is interpreted not as a stable tectonic configuration but as representing a tectonic "snapshot" of an arc in the process of being rifted to form a back-arc basin. ?? 1984.

The Role of Crustal Tectonics in Volcano Dynamics (ROCTEVODY) along the Southern Andes: seismological study with emphasis on Villarrica Volcano

NASA Astrophysics Data System (ADS)

Mora-Stock, Cindy; Tassara, Andrés

2016-04-01

The Southern Andean margin is intrinsically related to the Liquiñe-Ofqui Fault Zone (LOFZ), a 1000 km-long dextral strike-slip arc-parallel fault on which most of the volcanic centers of the Southern Volcanic Zone (SCVZ) of the Andes are emplaced. At large spatial (102 - 103 km) and temporal (105 - 107 yr) scales, regional tectonics linked to partitioning of the oblique convergence controls the distribution of magma reservoirs, eruption rates and style, as well as the magma evolution. At small scales in space (< 102 km) and time (10-1 - 102 yr), stress transfer mechanisms between magma reservoirs and seismically-active faults are though to transiently change the regional stress field, thus leading to eruptions and fault (re)activation. However, the mechanisms by which the interaction between (megathrust and crustal) earthquakes and volcanic eruptions actually occur, in terms of generating the relationships and characteristics verified at the long term, are still poorly understood. Since 2007, the Southern Andean margin has presented an increase of its tectonic and eruptive activity with several volcanic crisis and eruptions taking place in association with significant seismicity clusters and earthquakes both in the megathrust and the LOFZ. This increased activity offers a unique opportunity to improve our understanding of the physical relation between contemporary tectono-volcanic processes and the long-term construction of the LOFZ-SVZ system. Taking advantage of this opportunity by means of an integrated analysis of geodetic and seismological data through finite element numerical modeling at the scale of the entire margin and for selected cases is the main goal of project Active Tectonics and Volcanism at the Southern Andes (ACT&VO-SA, see Tassara et al. this meeting). Into the framework of the ACT&VO-SA project, the complementary ROCTEVODY-Villarrica project concentrates on the role that inherited crustal structures have in the volcano dynamics. The focus is on

Sheveluch Volcano, Kamchatka, Russia

NASA Image and Video Library

2010-04-05

Sheveluch Volcano in Kamchatka, Siberia, is one of the frequently active volcanoes located in eastern Siberia. In this image from NASA Terra spacecraft, brownish ash covers the southern part of the mountain, under an ash-laden vertical eruption plume.

Volcano-hazard zonation for San Vicente volcano, El Salvador

USGS Publications Warehouse

Major, J.J.; Schilling, S.P.; Pullinger, C.R.; Escobar, C.D.; Howell, M.M.

2001-01-01

San Vicente volcano, also known as Chichontepec, is one of many volcanoes along the volcanic arc in El Salvador. This composite volcano, located about 50 kilometers east of the capital city San Salvador, has a volume of about 130 cubic kilometers, rises to an altitude of about 2180 meters, and towers above major communities such as San Vicente, Tepetitan, Guadalupe, Zacatecoluca, and Tecoluca. In addition to the larger communities that surround the volcano, several smaller communities and coffee plantations are located on or around the flanks of the volcano, and major transportation routes are located near the lowermost southern and eastern flanks of the volcano. The population density and proximity around San Vicente volcano, as well as the proximity of major transportation routes, increase the risk that even small landslides or eruptions, likely to occur again, can have serious societal consequences. The eruptive history of San Vicente volcano is not well known, and there is no definitive record of historical eruptive activity. The last significant eruption occurred more than 1700 years ago, and perhaps long before permanent human habitation of the area. Nevertheless, this volcano has a very long history of repeated, and sometimes violent, eruptions, and at least once a large section of the volcano collapsed in a massive landslide. The oldest rocks associated with a volcanic center at San Vicente are more than 2 million years old. The volcano is composed of remnants of multiple eruptive centers that have migrated roughly eastward with time. Future eruptions of this volcano will pose substantial risk to surrounding communities.

Volcanic hotspots of the central and southern Andes as seen from space by ASTER and MODVOLC between the years 2000-2011

NASA Astrophysics Data System (ADS)

Jay, J.; Pritchard, M. E.; Mares, P. J.; Mnich, M. E.; Welch, M. D.; Melkonian, A. K.; Aguilera, F.; Naranjo, J.; Sunagua, M.; Clavero, J. E.

2011-12-01

We examine 153 volcanoes and geothermal areas in the central, southern, and austral Andes for temperature anomalies between 2000-2011 from two different spacebourne sensors: 1) those automatically detected by the MODVOLC algorithm (Wright et al., 2004) from MODIS and 2) manually identified hotspots in nighttime images from ASTER. Based on previous work, we expected to find 8 thermal anomalies (volcanoes: Ubinas, Villarrica, Copahue, Láscar, Llaima, Chaitén, Puyehue-Cordón Caulle, Chiliques). We document 31 volcanic areas with pixel integrated temperatures of 4 to more than 100 K above background in at least two images, and another 29 areas that have questionable hotspots with either smaller anomalies or a hotspot in only one image. Most of the thermal anomalies are related to known activity (lava and pyroclastic flows, growing lava domes, fumaroles, and lakes) while others are of unknown origin or reflect activity at volcanoes that were not thought to be active. A handful of volcanoes exhibit temporal variations in the magnitude and location of their temperature anomaly that can be related to both documented and undocumented pulses of activity. Our survey reveals that low amplitude volcanic hotspots detectable from space are more common than expected (based on lower resolution data) and that these features could be more widely used to monitor changes in the activity of remote volcanoes. We find that the shape, size, magnitude, and location on the volcano of the thermal anomaly vary significantly from volcano to volcano, and these variations should be considered when developing algorithms for hotspot identification and detection. We compare our thermal results to satellite InSAR measurements of volcanic deformation and find that there is no simple relationship between deformation and thermal anomalies - while 31 volcanoes have continuous hotspots, at least 17 volcanoes in the same area have exhibited deformation, and these lists do not completely overlap. In

Revisiting Jorullo volcano (Mexico): monogenetic or polygenetic volcano?

NASA Astrophysics Data System (ADS)

Delgado Granados, H.; Roberge, J.; Farraz Montes, I. A.; Victoria Morales, A.; Pérez Bustamante, J. C.; Correa Olan, J. C.; Gutiérrez Jiménez, A. J.; Adán González, N.; Bravo Cardona, E. F.

2007-05-01

Jorullo volcano is located near the volcanic front of the westernmost part of the Trans-Mexican Volcanic Belt, which is related to the subduction of the Cocos plate beneath the North American plate. This part of the TMVB is known as the Michoacán-Guanajuato Volcanic Field, a region where widespread monogenetic volcanism is present although polygenetic volcanism is also recognized (i. e. Tancítaro volcano; Ownby et al., 2006). Jorullo volcano was born in the middle of crop fields. During its birth several lava flows were emitted and several cones were constructed. The main cone is the Jorullo proper, but there is a smaller cone on the north (Volcán del Norte), and three smaller cones aligned N-S on the south (Unnamed cone, UC; Volcán de Enmedio, VE; and Volcán del Sur, VS). The cone of Jorullo volcano is made up of tephra and lava flows erupted from the crater. The three southern cones show very interesting histories not described previously. VE erupted highly vesiculated tephras including xenoliths from the granitic basement. VS is made of spatter and bombs. A very well preserved hummocky morphology reveals that VE and VS collapsed towards the west. After the collapses, phreatomagmatic activity took place at the UC blanketing VE, VS and the southern flank of the Jorullo cone with sticky surge deposits. The excellent study by Luhr and Carmichael (1985) indicates that during the course of the eruption, lavas evolved from primitive basalt to basaltic andesite, although explosive products show a reverse evolution pattern (Johnson et al., 2006). We mapped lava flows not described by the observers in the 18th century nor considered in previous geologic reports as part of the Jorullo lavas. These lavas are older, distributed to the west and south, and some of them resemble the lava flows from La Pilita volcano, a cone older than Jorullo (Luhr and Carmichael, 1985). These lava flows were not considered before because they were not extruded during the 1759

Back-arc basalts from the Loncopue graben (Province of Neuquen, Argentina)

NASA Astrophysics Data System (ADS)

Varekamp, J. C.; Hesse, A.; Mandeville, C. W.

2010-11-01

Young basaltic back-arc volcanoes occur east of the main Andes chain at about 37.5°-39°S in the Loncopue graben, Province of Neuquen, Argentina. These olivine-rich basalts and trachybasalts have up to 8% MgO, with high Ni and Cr contents, but highly variable incompatible element concentrations. Mafic lava flows and cinder cones at the southern end of the graben lack phenocrystic plagioclase. The northern samples have relative Ta-Nb depletions and K, Pb and LREE enrichment. These samples strongly resemble rocks of the nearby arc volcanoes Copahue and Caviahue, including their Fe-Ti enrichment relative to the main Andes arc rocks. The Sr, Nd and Pb isotope ratios show that the source regions of these back-arc basalts are enriched in subducted components that were depleted in the aqueous mobile elements such as Cs, Sr and Ba as a result of prior extractions from the subducted complex below the main arc. Some mafic flows show slightly low 206Pb/ 204Pb and 143Nd/ 144Nd values as well as incompatible trace element ratios similar to southern Patagonia plateau back-arc basalts, suggesting contributions from an EM1 mantle source. Geothermometry and barometry suggest that the basalts crystallized and fractionated small amounts of olivine and spinel at ˜ 35 km depth at temperatures of 1170-1220 °C, at about QFM + 0.5 to QFM + 1 with 1-2% H 2O, and then rose rapidly to the surface. The Loncopue graben back-arc basalts are transitional in composition between the South Patagonia back-arc plateau basalts and the Caviahue and Copahue arc volcanoes to the northwest. The EM1 source endmember is possibly the subcontinental lithospheric mantle. Strong variations in incompatible element enrichment and isotopic compositions between closely spaced cinder cones and lava flows suggest a heterogeneous mantle source for the Loncopue graben volcanics.

Volcanic deformation in the Andes

NASA Astrophysics Data System (ADS)

Riddick, S.; Fournier, T.; Pritchard, M.

2009-05-01

We present the results from an InSAR survey of volcanic activity in South America. We use data from the Japanese Space Agency's ALOS L-band radar satellite from 2006-2009. The L-band instrument provides better coherence in densely vegetated regions, compared to the shorter wave length C-band data. The survey reveals volcano related deformation in regions, north, central and southern, of the Andes volcanic arc. Since observations are limited to the austral summer, comprehensive coverage of all volcanoes is not possible. Yet, our combined observations reveal volcanic/hydrothermal deformation at Lonquimay, Llaima, Laguna del Maule, and Chaitén volcanoes, extend deformation measurements at Copahue, and illustrate temporal complexity to the previously described deformation at Cerro Hudson and Cordón Caulle. No precursory deformation is apparent before the large Chaitén eruption (VEI_5) of 2 May 2008, (at least before 16 April) suggesting rapid magma movement from depth at this long dormant volcano. Subsidence at Ticsani Volcano occurred coincident with an earthquake swarm in the same region.

Geochemical constraints on possible subduction components in lavas of Mayon and Taal Volcanoes, Southern Luzon, Philippines

USGS Publications Warehouse

Castillo, P.R.; Newhall, C.G.

2004-01-01

Mayon is the most active volcano along the east margin of southern Luzon, Philippines. Petrographic and major element data indicate that Mayon has produced a basaltic to andesitic lava series by fractional crystallization and magma mixing. Trace element data indicate that the parental basalts came from a heterogeneous mantle source. The unmodified composition of the mantle wedge is similar to that beneath the Indian Ocean. To this mantle was added a subduction component consisting of melt from subducted pelagic sediment and aqueous fluid dehydrated from the subducted basaltic crust. Lavas from the highly active Taal Volcano on the west margin of southern Luzon are compositionally more variable than Mayon lavas. Taal lavas also originated from a mantle wedge metasomatized by aqueous fluid dehydrated from the subducted basaltic crust and melt plus fluid derived from the subducted terrigenous sediment. More sediment is involved in the generation of Taal lavas. Lead isotopes argue against crustal contamination. Some heterogeneity of the unmodified mantle wedge and differences in whether the sediment signature is transferred into the lava source through an aqueous fluid or melt phase are needed to explain the regional compositional variation of Philippine arc lavas. ?? Oxford University Press 2004; all rights reserved.

Interdisciplinary studies of eruption at Chaiten Volcano, Chile

Treesearch

John S. Pallister; Jon J. Major; Thomas C. Pierson; Richard P. Hoblitt; Jacob B. Lowenstern; John C. Eichelberger; Lara Luis; Hugo Moreno; Jorge Munoz; Jonathan M. Castro; Andres Iroume; Andrea Andreoli; Julia Jones; Fred Swanson; Charlie Crisafulli

2010-01-01

There was keen interest within the volcanology community when the first large eruption of high-silica rhyolite since that of Alaska's Novarupta volcano in 1912 began on 1 May 2008 at Chaiten volcano, southern Chile, a 3-kilometer-diameter caldera volcano with a prehistoric record of rhyolite eruptions. Vigorous explosions occurred through 8 May 2008, after which...

Volcano Hazards Assessment for Medicine Lake Volcano, Northern California

USGS Publications Warehouse

Donnelly-Nolan, Julie M.; Nathenson, Manuel; Champion, Duane E.; Ramsey, David W.; Lowenstern, Jacob B.; Ewert, John W.

2007-01-01

Medicine Lake volcano (MLV) is a very large shield-shaped volcano located in northern California where it forms part of the southern Cascade Range of volcanoes. It has erupted hundreds of times during its half-million-year history, including nine times during the past 5,200 years, most recently 950 years ago. This record represents one of the highest eruptive frequencies among Cascade volcanoes and includes a wide variety of different types of lava flows and at least two explosive eruptions that produced widespread fallout. Compared to those of a typical Cascade stratovolcano, eruptive vents at MLV are widely distributed, extending 55 km north-south and 40 km east-west. The total area covered by MLV lavas is >2,000 km2, about 10 times the area of Mount St. Helens, Washington. Judging from its long eruptive history and its frequent eruptions in recent geologic time, MLV will erupt again. Although the probability of an eruption is very small in the next year (one chance in 3,600), the consequences of some types of possible eruptions could be severe. Furthermore, the documented episodic behavior of the volcano indicates that once it becomes active, the volcano could continue to erupt for decades, or even erupt intermittently for centuries, and very likely from multiple vents scattered across the edifice. Owing to its frequent eruptions, explosive nature, and proximity to regional infrastructure, MLV has been designated a 'high threat volcano' by the U.S. Geological Survey (USGS) National Volcano Early Warning System assessment. Volcanic eruptions are typically preceded by seismic activity, but with only two seismometers located high on the volcano and no other USGS monitoring equipment in place, MLV is at present among the most poorly monitored Cascade volcanoes.

Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue-Caviahue Volcanic Complex (Argentina)

NASA Astrophysics Data System (ADS)

Chiodini, Giovanni; Cardellini, Carlo; Lamberti, María Clara; Agusto, Mariano; Caselli, Alberto; Liccioli, Caterina; Tamburello, Giancarlo; Tassi, Franco; Vaselli, Orlando; Caliro, Stefano

2015-10-01

The north-western sector of Caviahue caldera (Argentina), close to the active volcanic system of Copahue, is characterized by the presence of several hydrothermal sites that host numerous fumarolic emissions, anomalous soil diffuse degassing of CO2 and hot soils. In March 2014, measurements of soil CO2 fluxes in 5 of these sites (namely, Las Máquinas, Las Maquinitas I, Las Maquinitas II, Anfiteatro, and Termas de Copahue) allowed an estimation that 165 t of deeply derived CO2 is daily released. The gas source is likely related to a relatively shallow geothermal reservoir containing a single vapor phase as also suggested by both the geochemical data from the 3 deep wells drilled in the 1980s and gas geoindicators applied to the fumarolic discharges. Gas equilibria within the H-C-O gas system indicate the presence of a large, probably unique, single phase vapor zone at 200-210 °C feeding the hydrothermal manifestations of Las Máquinas, Las Maquinitas I and II and Termas de Copahue. A natural thermal release of 107 MW was computed by using CO2 as a tracer of the original vapor phase. The magmatic signature of the incondensable fumarolic gases, the wide expanse of the hydrothermal areas and the remarkable high amount of gas and heat released by fluid expulsion seem to be compatible with an active magmatic intrusion beneath this portion of the Caviahue caldera.

Gas geochemistry and methane emission from Dushanzi mud volcanoes in the southern Junggar Basin, NW China

NASA Astrophysics Data System (ADS)

Zheng, Guodong; Ma, Xiangxian; Guo, Zhengfu; Hilton, David R.; Xu, Wang; Liang, Shouyun; Fan, Qiaohui; Chen, Wenxing

2017-11-01

There are many mud volcanoes in the southern margin of the Junggar Basin, northwest China, of which the Dushanzi area is the most typical and active one, emitting large amount of greenhouse gases associated with water and mud. The emitted gas is dominated by methane (average 90.1%), together with other gases, such as ethane (4.84-5.46%), propane (0.06-0.90%), CO2 (0.67-1.0%), and N2 (2.8-3.3%). The carbon (δ13C1) and hydrogen (δD) isotopic ratios of methane are in the ranges of -40.6‰ to -45.0‰ and -221‰ to -249‰, respectively, whereas carbon isotope ratios of ethane (δ13C2) are -25.2‰ to -27.6‰. Based on δ13C values, the released gas is characterized as a thermogenic coal-type and possibly originated from the middle-low Jurassic coal-bearing sequences according to the gas-source correlation and regional geology. Helium isotopes show a crustal source. The methane flux of Dushanzi mud volcanoes from both macro-seepage (craters/vents) and micro-seepage (ground soil exhalation) ranged over the orders of magnitude, from 0.4-2.7 kg d-1 and 4950 mg m-2 d-1 on average, respectively. Positive CH4 fluxes from dry soil were widespread throughout the investigated areas. The total CH4 emission from Dushanzi mud volcanoes is estimated to be at least 22.6 tons a-1, of which about 89% is from micro-seepage surrounding the mud volcano vents.

New insight from noble gas and stable isotopes of geothermal/hydrothermal fluids at Caviahue-Copahue Volcanic Complex: Boiling steam separation and water-rock interaction at shallow depth

NASA Astrophysics Data System (ADS)

Roulleau, Emilie; Tardani, Daniele; Sano, Yuji; Takahata, Naoto; Vinet, Nicolas; Bravo, Francisco; Muñoz, Carlos; Sanchez, Juan

2016-12-01

We measured noble gas and stable isotopes of the geothermal and hydrothermal fluids of the Caviahue-Copahue Volcanic Complex (CCVC), one of the most important geothermal systems in Argentina/Chile, in order to provide new insights into fluid circulation and origin. With the exception of Anfiteatro and Chancho-co geothermal systems, mantle-derived helium dominates in the CCVC fluids, with measured 3He/4He ratios up to 7.86Ra in 2015. Their positive δ15N is an evidence for subducted sediment-derived nitrogen, which is commonly observed in subduction settings. Both He-N2-Ar composition and positive correlation between δD-H2O and δ18O-H2O suggest that the fluids from Anfiteatro and Chancho-co (and partly from Pucon-Mahuida as well, on the southern flank of Copahue volcano) represent a meteoric water composition with a minor magmatic contribution. The Ne, Kr and Xe isotopic compositions are entirely of atmospheric origin, but processes of boiling and steam separation have led to fractionation of their elemental abundances. We modeled the CCVC fluid evolution using Rayleigh distillation curves, considering an initial air saturated geothermal water (ASGW) end-member at 250 and 300 °C, followed by boiling and steam separation at lower temperatures (from 200 °C to 150 °C). Between 2014 and 2015, the CCVC hydrogen and oxygen isotopes shifted from local meteoric water-dominated to andesitic water-dominated signature. This shift is associated with an increase of δ13C values and Stotal, HCl and He contents. These characteristics are consistent with a change in the gas ascent pathway between 2014 and 2015, which in turn induced higher magmatic-hydrothermal contribution in the fluid signature. The composition of the magmatic source of the CCVC fluids is: 3He/4He = 7.7Ra, δ15N = + 6‰, and δ13C = - 6.5‰. Mixing models between air-corrected He and N suggest the involvement of 0.5% to 5% of subducted sediments in the magmatic source. The magmatic sulfur isotopic

Lahar hazard assessment in the southern drainage system of Cotopaxi volcano, Ecuador: Results from multiscale lahar simulations

NASA Astrophysics Data System (ADS)

Pistolesi, Marco; Cioni, Raffaello; Rosi, Mauro; Aguilera, Eduardo

2014-02-01

The ice-capped Cotopaxi volcano is known worldwide for the large-scale, catastrophic lahars that have occurred in connection with historical explosive eruptions. The most recent large-scale lahar event occurred in 1877 when scoria flows partially melted ice and snow of the summit glacier, generating debris flows that severely impacted all the river valleys originating from the volcano. The 1877 lahars have been considered in the recent years as a maximum expected event to define the hazard associated to lahar generation at Cotopaxi. Conversely, recent field-based studies have shown that such debris flows have occurred several times during the last 800 years of activity at Cotopaxi, and that the scale of lahars has been variable, including events much larger than that of 1877. Despite a rapid retreat of the summit ice cap over the past century, in fact, there are no data clearly suggesting that future events will be smaller than those observed in the deposits of the last 800 years of activity. In addition, geological field data prove that the lahar triggering mechanism also has to be considered as a key input parameter and, under appropriate eruptive mechanisms, a hazard scenario of a lahar with a volume 3-times larger than the 1877 event is likely. In order to analyze the impact scenarios in the southern drainage system of the volcano, simulations of inundation areas were performed with a semi-empirical model (LAHARZ), using input parameters including variable water volume. Results indicate that a lahar 3-times larger than the 1877 event would invade much wider areas than those flooded by the 1877 lahars along the southern valley system, eventually impacting highly-urbanized areas such as the city of Latacunga.

Relation between alternating open/closed-conduit conditions and deformation patterns: An example from the Somma-Vesuvius volcano (southern Italy)

NASA Astrophysics Data System (ADS)

Tramparulo, F. D. A.; Vitale, S.; Isaia, R.; Tadini, A.; Bisson, M.; Prinzi, E. P.

2018-07-01

We present the results of a meso-scale systematic structural analysis of fractures, faults and dykes exposed at the Somma-Vesuvius volcano (southern Italy). Observed fractures include: (i) radial and tangential (with respect the caldera axis), sub-metric to metric joints associated with the edifice load and volcano-tectonic activity (i.e. inflation, deflation and caldera collapse stages) and (ii) decameter-scale fractures related to volcano flank instabilities. For the Somma-Vesuvius volcano, preexisting radial joints were commonly reactivated as transfer faults during the caldera formation, allowing different blocks to move toward the center of the collapsing area. Dykes occur with different geometries, including en-echelon structures bounding structural depressions. The orientation analysis of all structures indicates that they are preferentially oriented. Furthermore, we provide a morphological lineament analysis using high-resolution Digital Terrain Models of Somma-Vesuvius. Azimuth and spatial distribution of dykes and morphological lineaments were analyzed for comparison with the old Somma Crater and Gran Cono axes, respectively. Results highlight the overprinting of radial and clustered strain patterns recorded in different volcano-tectonic evolution stages. We suggest a possible deformation evolution model in which structures develop along either radial or preferential trends, highlighting different volcanic conditions: (i) where radial patterns occur, the structures developed during volcanic inflation cycles with a closed magmatic conduit condition whereas (ii) clustered patterns are probably associated with a regional strain field that overcomes the local deformation field, a situation typical in the case of open-conduit activity.

Initial H2O content and conditions of parent magma origin for Gorely volcano (Southern Kamchatka) estimated by trace element thermobarometry

NASA Astrophysics Data System (ADS)

Nazarova, D. P.; Portnyagin, M. V.; Krasheninnikov, S. P.; Mironov, N. L.; Sobolev, A. V.

2017-01-01

The formation conditions of the parental magmas of Gorely volcano, which is located behind a volcanic front in Southern Kamchatka, have been evaluated using the modern methods of micro-element thermobarometry. These magmas contained 1.7 ± 0.8 (2σ) wt % of H2O, the majority (82%) of which has been lost from inclusions. They crystallized at 1121 ± 17°C and an oxygen fugacity of ΔQFM 1.2 ± 0.2, and could have been produced by about 11% melting of an enriched MORB source (E-DMM) at a temperature of about 1270°C, and a pressure of about 1.5 GPa. A distinctive feature of Gorely volcano, compared with frontal volcanoes of Kamchatka, is the unusually high temperature (925 ± 20°C) of formation of the subduction component corresponding to the region of existence of water-bearing melts.

Thermalism in Argentina. Alternative or complementary dermatologic therapy.

PubMed

Ubogui, J; Stengel, F M; Kien, M C; Sevinsky, L; Rodríguez Lupo, L

1998-11-01

Our study took place in the region of the Copahue Volcano in the Andes Mountain range, 1900 m above sea level. Fifty-five patients who came to the Copahue Thermal Basin Complex (Neuquén, Argentina) for treatment of psoriasis vulgaris were clinically evaluated for participation in this study. Thermal products--waters, mud, and/or algae--were the only therapeutic agents used, except for bland emollients for xerosis. Treatment for brief periods (10 +/- 3 days) resulted in notable improvement.

AMS Radiocarbon dating of paleosols intercalated with tephra layers from Mayon Volcano, southern Luzon, Philippines: A preliminary report

USGS Publications Warehouse

Mirabueno, Ma. Hannah T.; Okuno, Mitsuru; Nakamura, Toshio; Newhall, Christopher G.; Kobayashi, Tetsuo

2006-01-01

This paper presents the AMS 14C dates of paleosols intercalated with tephra layers in the vicinity of Mayon Volcano, southern Luzon, Philippines. the obtained 14C dates are almost consistent with the stratigraphy of the Mayon tephra group. On the basis of calibrated 14C age of soil layer directly overlying the lowest ash layer, the oldest eruptive event must have taken place shortly before 20 cal kyr BP. This age is younger than the previous estimates for Mayon.

"Mediterranean volcanoes vs. chain volcanoes in the Carpathians"

NASA Astrophysics Data System (ADS)

Chivarean, Radu

2017-04-01

or dome complexes. Dacitic volcanoes are smaller in size and consist of lava dome complexes, in places with associated pyroclastic cones and volcanic aprons. The volcanic history of Carpathian volcanic chain lasts since ca. 15 Ma, with the youngest occurring in the southern chain-terminus; the last eruption of Ciomadu volcano (Harghita) was ca. 10000 years ago. Using the knowledge acquired during the compulsory curriculum and complementary activities we we consider that the outdoor education is the best way to establish a relationship between the theory and the landscape reality in the field. As a follow up to our theoretical approach for the Earth's crust we organized two study trips in our region. During the first one the students could walk in a real crater, see scoria deposits and admire the basalt columns from Racos. In the second activity they could climb the Ciomadu volcano and go down to observe the crater lake St. Anna, the single volcanic lake in central Europe.

Volcanic hazards at Atitlan volcano, Guatemala

USGS Publications Warehouse

Haapala, J.M.; Escobar Wolf, R.; Vallance, James W.; Rose, William I.; Griswold, J.P.; Schilling, S.P.; Ewert, J.W.; Mota, M.

2006-01-01

Atitlan Volcano is in the Guatemalan Highlands, along a west-northwest trending chain of volcanoes parallel to the mid-American trench. The volcano perches on the southern rim of the Atitlan caldera, which contains Lake Atitlan. Since the major caldera-forming eruption 85 thousand years ago (ka), three stratovolcanoes--San Pedro, Toliman, and Atitlan--have formed in and around the caldera. Atitlan is the youngest and most active of the three volcanoes. Atitlan Volcano is a composite volcano, with a steep-sided, symmetrical cone comprising alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs. Eruptions of Atitlan began more than 10 ka [1] and, since the arrival of the Spanish in the mid-1400's, eruptions have occurred in six eruptive clusters (1469, 1505, 1579, 1663, 1717, 1826-1856). Owing to its distance from population centers and the limited written record from 200 to 500 years ago, only an incomplete sample of the volcano's behavior is documented prior to the 1800's. The geologic record provides a more complete sample of the volcano's behavior since the 19th century. Geologic and historical data suggest that the intensity and pattern of activity at Atitlan Volcano is similar to that of Fuego Volcano, 44 km to the east, where active eruptions have been observed throughout the historical period. Because of Atitlan's moderately explosive nature and frequency of eruptions, there is a need for local and regional hazard planning and mitigation efforts. Tourism has flourished in the area; economic pressure has pushed agricultural activity higher up the slopes of Atitlan and closer to the source of possible future volcanic activity. This report summarizes the hazards posed by Atitlan Volcano in the event of renewed activity but does not imply that an eruption is imminent. However, the recognition of potential activity will facilitate hazard and emergency preparedness.

Lahar-hazard zonation for San Miguel volcano, El Salvador

USGS Publications Warehouse

Major, J.J.; Schilling, S.P.; Pullinger, C.R.; Escobar, C.D.; Chesner, C.A.; Howell, M.M.

2001-01-01

San Miguel volcano, also known as Chaparrastique, is one of many volcanoes along the volcanic arc in El Salvador. The volcano, located in the eastern part of the country, rises to an altitude of about 2130 meters and towers above the communities of San Miguel, El Transito, San Rafael Oriente, and San Jorge. In addition to the larger communities that surround the volcano, several smaller communities and coffee plantations are located on or around the flanks of the volcano, and the PanAmerican and coastal highways cross the lowermost northern and southern flanks of the volcano. The population density around San Miguel volcano coupled with the proximity of major transportation routes increases the risk that even small volcano-related events, like landslides or eruptions, may have significant impact on people and infrastructure. San Miguel volcano is one of the most active volcanoes in El Salvador; it has erupted at least 29 times since 1699. Historical eruptions of the volcano consisted mainly of relatively quiescent emplacement of lava flows or minor explosions that generated modest tephra falls (erupted fragments of microscopic ash to meter sized blocks that are dispersed into the atmosphere and fall to the ground). Little is known, however, about prehistoric eruptions of the volcano. Chemical analyses of prehistoric lava flows and thin tephra falls from San Miguel volcano indicate that the volcano is composed dominantly of basalt (rock having silica content

Potential ash impact from Antarctic volcanoes: Insights from Deception Island's most recent eruption.

PubMed

Geyer, A; Marti, A; Giralt, S; Folch, A

2017-11-28

Ash emitted during explosive volcanic eruptions may disperse over vast areas of the globe posing a threat to human health and infrastructures and causing significant disruption to air traffic. In Antarctica, at least five volcanoes have reported historic activity. However, no attention has been paid to the potential socio-economic and environmental consequences of an ash-forming eruption occurring at high southern latitudes. This work shows how ash from Antarctic volcanoes may pose a higher threat than previously believed. As a case study, we evaluate the potential impacts of ash for a given eruption scenario from Deception Island, one of the most active volcanoes in Antarctica. Numerical simulations using the novel MMB-MONARCH-ASH model demonstrate that volcanic ash emitted from Antarctic volcanoes could potentially encircle the globe, leading to significant consequences for global aviation safety. Results obtained recall the need for performing proper hazard assessment on Antarctic volcanoes, and are crucial for understanding the patterns of ash distribution at high southern latitudes with strong implications for tephrostratigraphy, which is pivotal to synchronize palaeoclimatic records.

Mayon volcano, southeast Luzon, Philippines

NASA Technical Reports Server (NTRS)

2002-01-01

Mayon volcano is the most active volcano in the Philippines, located just north of the coastal town of Legaspi in southern Luzon about 325 km southeast of Manila. Mayon is a near-perfect cone; its steep, forested slopes look rather like a bull's eye when viewed from above. For scale, Mayon's circular footprint is about 16 km in diameter. This photograph was taken from the Space Shuttle on April 8, 1997. At the time the photo was taken, Mayon sported a steam plume from the summit. The lighter (non-forested) regions that radiate from the summit to the southern slopes are flows from eruptions that have occurred over the past twenty-five years. The current eruption, which started June 24, 2001, is sending flows down the southeast slope in the general direction of Legaspi. Image STS083-747-88 was provided by the by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

The 2011-2012 eruption of Cordón Caulle volcano (Southern Andes): Evolution, crisis management and current hazards

NASA Astrophysics Data System (ADS)

Silva Parejas, C.; Lara, L. E.; Bertin, D.; Amigo, A.; Orozco, G.

2012-04-01

A new kind of integrated approach was for first time achieved during the eruptive crisis of Cordón Caulle volcano (Southern Andes, 40.59°S, 72.12°W) in Chile. The monitoring network of SERNAGEOMIN around the volcano detected the increasing precursory seismicity, alerting the imminence of an eruption about 5 hours before its onset, on June 4, 2011. In addition, SERNAGEOMIN generated daily forecasts of tephra dispersal and fall (ASHFALL advection-diffusion model), and prepared simulations of areas affected by the possible occurrence of lahars and pyroclastic flows. Models were improved with observed effects on the field and satellite imagery, resulting in a good correlation. The information was timely supplied to the authorities as well as recommendations in order to better precise the vulnerable areas. Eruption has initially occurred from a couple of overlapped cones located along the eastern fault scarp of the Pleistocene-Holocene extensional graben of Cordón Caulle. Eruptive products have virtually the same bulk composition as those of the historical 1921 and 1960 eruptions, corresponding to phenocryst-poor rhyodacites (67-70 % SiO2). During the first eruptive stage, a ca. 15-km strong Plinian column lasting 27 hours emitted 0.2-0.4 km3 of magma (DRE). Thick tephra deposits have been accumulated in Chile and Argentina, whereas fine particles and aerosols dispersion disrupted air navigation across the Southern Hemisphere. The second ongoing eruptive stage, which started in mid-June, has been characterized by lava emission already covering a total area comparable to the 1960 lava flows with a total estimated volume <0.25 km3 (at the end of December 2011). Weak but persistent plumes have caused preventive flight suspensions in Chile and Argentina until the end of the year. Main current hazards at Cordón Caulle volcano are fine tephra fallout, secondary lahars, minor explosions and lava flow front collapse. Even if this case can be considered successful from the

Exploring the Llaima Volcano Using Receiver Functions

NASA Astrophysics Data System (ADS)

Bishop, J. W.; Biryol, C.; Lees, J. M.

2016-12-01

The Llaima volcano in Chile is one of the most active volcanos in the Southern Andes, erupting at least 50 times since 1640. To understand the eruption dynamics behind these frequent paroxysms, it is important to identify the depth and extent of the magma chamber beneath the volcano. Furthermore, it is also important to identify structural controls on the magma storage regions and volcanic plumbing system, such as fault and fracture zones. To probe these questions, a dense, 26 station broadband seismic array was deployed around the Llaima volcano for 3 months (January to March, 2015). Additionally, broadband seismic data from 7 stations in the nearby Observatorio Volcanológico de Los Andes del Sur (OVDAS) seismic network was also obtained for this period. Teleseismic receiver functions were calculated from this combined data using an iterative deconvolution technique. Receiver function stacks (both H-K and CCP) yield seismic images of the deep structure beneath the volcano. Initial results depict two low velocity layers at approximately 4km and 12km. Furthermore, Moho calculations are 5-8 km deeper than expected from regional models, but a shallow ( 40 km) region is detected beneath the volcano peak. A large high Vp/Vs ratio anomaly (Vp/Vs > 0.185) is discernable to the east of the main peak of the volcano.

Magnetotelluric survey of Ischia resurgent caldera (Southern Italy): inference for volcano-tectonics and dynamic

NASA Astrophysics Data System (ADS)

Carlino, S.; Di Giuseppe, M. G.; Troiano, A.

2017-12-01

The island of Ischia (located in the Bay of Naples) represents a peculiar case of well-exposed caldera that has experienced a large (>800m) and rapid resurgence, until recent time. It gives us the possibility for a better understanding of caldera resurgence process, by integrating the available geological information with new geophysical data of the deeper structures associated to the resurgence. To this aim, a magnetotelluric survey of the island, has been performed along two main profiles of the central-western sector, obtaining the first electrical resistivity map down to a depth of 3km. The resurgence is tough to be associated to a shallow magma intrusion, which also produced a vigorous hot fluids circulation with high geothermal gradients (>150°Ckm-1) in the southern and western sector. The interpretation of resistivity variations allow us to recognize the main volcano-tectonic features of central-western part of the island, along the two profiles, such as the presence of a possible very shallow magmatic intrusion to a depth of about 1km, the tectonic structures bordering the resurgent area and the occurrence of large thermal anomaly of the western sector. All these data are fundamental for the assessment of volcano-dynamic of the island and associated hazard. Furthermore, this study show a not common example of a large resurgence that is likely generated by a laccolith intrusion. This process is generally associated to the arrival of fresh magma into the system that, in turn, may imply imminent eruption and high volcanic hazard.

Kinematics and age of Early Tertiary trench parallel volcano-tectonic lineaments in southern Mexico: Tectonic implications

NASA Astrophysics Data System (ADS)

Martini, M.; Ferrari, L.; Lopez Martinez, M.; Cerca Martinez, M.; Serrano Duran, L.

2007-05-01

We present new geological, structural, and geochronological data that constrain the timing and geometry of Early Tertiary strike slip deformation in southwestern Mexico and its relation with the concurrent magmatic activity. Geologic mapping in Guerrero and Michoacan States documented two regional WNW trending volcano-tectonic lineaments sub parallel to the present trench. The southernmost lineament runs for ~140 km from San Miguel Totolapan area (NW Guerrero) to Sanchiqueo (SE Michoacan), and passes through Ciudad Altamirano. Its southeastern part is marked by the alignment of at least eleven silicic to intermediate major domes as well as by the course of the Balsas River. The northwestern part of the lineament is characterized by ductile left lateral shear zones in Early Tertiary plutonic rocks observed in the Rio Chiquito valley. Domes near Ciudad Altamirano are unaffected by ductile shearing and yielded a ~42 Ma 40Ar/39Ar age, setting a minimum age for this deformation. The northern volcano-tectonic lineament runs for ~190 km between the areas of Huitzuco in northern Guerrero and the southern part of the Tzitzio fold in eastern Michoacan. The Huautla, Tilzapotla, Taxco, La Goleta and Nanchititla silicic centers (all in the range 37-34 Ma) are emplaced along this lineament, which continues to the WNW trough a mafic dike swarm exposed north of Tiquicheo (37-35 Ma) and the Purungueo subvolcanic body (~42 Ma). These rocks, unaffected by ductile shearing, give a minimum age of deformation similar to the southern Totolapan-Sanquicheo lineament. Post ~42 Ma deformation is essentially brittle and is characterized by several left lateral and right lateral transcurrent faults with typical Riedel patterns. Other trench-parallel left lateral shear zones active in pre-Oligocene times were recently reported in western Oaxaca. The recognizing of Early Tertiary trench-parallel and left-lateral ductile shearing in internal areas of southern Mexico suggest a field of widely

Examining the interior of Llaima Volcano with receiver functions

NASA Astrophysics Data System (ADS)

Bishop, J. W.; Lees, J. M.; Biryol, C. B.; Mikesell, T. D.; Franco, L.

2018-02-01

Llaima Volcano in Chile is one of the largest and most active volcanoes in the southern Andes, with over 50 eruptions since the 1600s. After years of persistent degassing, Llaima most recently erupted in a series of violent Strombolian eruptions in 2007-2009. This period had few precursory signals, which highlights the need to obtain accurate magma storage information. While petrologic advancements have been made in understanding magma degassing and crystallization trends, a comprehensive seismic study has yet to be completed. Here, we present results of a receiver function survey utilizing a dense seismic array surrounding Llaima volcano. Application of H-κ stacking and common conversion point stacking techniques reveals a new Moho estimate and two structural anomalies beneath Llaima Volcano. We interpret a low velocity zone between 8 and 13 km depth as a newly imaged magma body.

Mud volcanoes of trinidad as astrobiological analogs for martian environments.

PubMed

Hosein, Riad; Haque, Shirin; Beckles, Denise M

2014-10-13

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil's Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region.

Mud Volcanoes of Trinidad as Astrobiological Analogs for Martian Environments

PubMed Central

Hosein, Riad; Haque, Shirin; Beckles, Denise M.

2014-01-01

Eleven onshore mud volcanoes in the southern region of Trinidad have been studied as analog habitats for possible microbial life on Mars. The profiles of the 11 mud volcanoes are presented in terms of their physical, chemical, mineralogical, and soil properties. The mud volcanoes sampled all emitted methane gas consistently at 3% volume. The average pH for the mud volcanic soil was 7.98. The average Cation Exchange Capacity (CEC) was found to be 2.16 kg/mol, and the average Percentage Water Content was 34.5%. Samples from three of the volcanoes, (i) Digity; (ii) Piparo and (iii) Devil’s Woodyard were used to culture bacterial colonies under anaerobic conditions indicating possible presence of methanogenic microorganisms. The Trinidad mud volcanoes can serve as analogs for the Martian environment due to similar geological features found extensively on Mars in Acidalia Planitia and the Arabia Terra region. PMID:25370529

Geologic field-trip guide to Mount Shasta Volcano, northern California

USGS Publications Warehouse

Christiansen, Robert L.; Calvert, Andrew T.; Grove, Timothy L.

2017-08-18

The southern part of the Cascades Arc formed in two distinct, extended periods of activity: “High Cascades” volcanoes erupted during about the past 6 million years and were built on a wider platform of Tertiary volcanoes and shallow plutons as old as about 30 Ma, generally called the “Western Cascades.” For the most part, the Shasta segment (for example, Hildreth, 2007; segment 4 of Guffanti and Weaver, 1988) of the arc forms a distinct, fairly narrow axis of short-lived small- to moderate-sized High Cascades volcanoes that erupted lavas, mainly of basaltic-andesite or low-silica-andesite compositions. Western Cascades rocks crop out only sparsely in the Shasta segment; almost all of the following descriptions are of High Cascades features except for a few unusual localities where older, Western Cascades rocks are exposed to view along the route of the field trip.The High Cascades arc axis in this segment of the arc is mainly a relatively narrow band of either monogenetic or short-lived shield volcanoes. The belt generally averages about 15 km wide and traverses the length of the Shasta segment, roughly 100 km between about the Klamath River drainage on the north, near the Oregon-California border, and the McCloud River drainage on the south (fig. 1). Superposed across this axis are two major long-lived stratovolcanoes and the large rear-arc Medicine Lake volcano. One of the stratovolcanoes, the Rainbow Mountain volcano of about 1.5–0.8 Ma, straddles the arc near the midpoint of the Shasta segment. The other, Mount Shasta itself, which ranges from about 700 ka to 0 ka, lies distinctly west of the High Cascades axis. It is notable that Mount Shasta and Medicine Lake volcanoes, although volcanologically and petrologically quite different, span about the same range of ages and bracket the High Cascades axis on the west and east, respectively.The field trip begins near the southern end of the Shasta segment, where the Lassen Volcanic Center field trip leaves

Variable Sources and Differentiation of Lavas from the Copahue-Caviahue Eruptive Complex, Neuquen Argentina

NASA Astrophysics Data System (ADS)

Todd, E.; Ort, M. H.

2012-12-01

Caldera collapse (˜180 km2) associated with a large Pliocene pyroclastic eruption and subsequent glacial erosion exposed an extensive and complex cross-section of pre-caldera volcanic history (at least 5 My) at the Copahue-Caviahue Eruptive Center (CCEC) in the Andean Southern Volcanic Zone (SVZ) of Argentina. Lava flows in wall exposures range from olivine-rich basaltic andesite to trachyte, are typically horizontal, vary in abundance and thickness at different wall exposures, and rarely correlate with flows in adjacent sections, although some lava and pyroclastic deposits from adjacent sections are similar in petrography, mineral assemblage, and geochemistry. Bulk-rock geochemical and isotopic data indicate at least two distinct primary melt types contributed to pre-caldera CCEC volcanism, and their differentiates produced a high-K and a low-K series. Incompatible element and isotope systematics suggest they are not related by differentiation of a common parental melt, and less-evolved examples of both types occur throughout the pre-caldera stratigraphic section, suggesting long-lived recharge of the local system by variably-sourced magmas. Petrographic and mineral chemistry evidence indicates that mixing of dissimilar magma types produced compositionally intermediate magmas. The location of the CCEC, rear of the volcanic front (VF), yet trenchward of regional backarc basin (BAB) volcanism, is reflected by the composition of CCEC lavas, which are transitional between local VF and BAB types. Thus, contrasting low- and high-K CCEC magmas in the SVZ rear-arc may reflect local focusing of VF-like (low-K) and BAB-like (high-K) melts.

Seismicity preliminary results in a geothermal and volcano activity area: study case Liquiñe-Ofqui fault system in Southern Andes, Chile

NASA Astrophysics Data System (ADS)

Estay, N. P.; Yáñez Morroni, G.; Crempien, J. G. F.; Roquer, T.

2017-12-01

Fluid transport through the crust takes place in domains with high permeability. For this reason, fault damage zones are a main feature where fluids may circulate unimpeded, since they have much larger permeability than normal country rocks. With the location of earthquakes, it is possible to infer fault geometry and stress field of the crust, therefore we can determine potential places where fluid circualtion is taking place. With that purpose, we installed a seismic network in an active volcanic-geothermal system, the Liquiñe-Ofqui Fault System (LOFS), located in Puyuhuapi, Southern Andes (44°-45°S). This allowed to link epicentral seismicity, focal mechanisms and surface expression of fluid circulation (hot-springs and volcanos). The LOFS is composed by two NS-striking dextral master faults, and several secondary NE-striking dextral and normal faults. Surface manifestation of fluid circulation in Puyuhuapi area are: 1) six hot-springs, most of them spatially associated with different mapped faults; 2) seven minor eruptive centers aligned over a 10-km-along one of the master NS-striking fault, and; 3) the Melimouyu strato-volcano without any spatial relationship with mapped faults. The network consists of 6 short period seismometers (S31f-2.0a sensor of IESE, with natural frequency of 2Hz), that were installed between July 2016 and August 2017; also 4 permanent broad-band seismometers (Guralp 6TD/ CD 24 sensor) which belong to the Volcano Observatory of Southern Andes (OVDAS). Preliminary results show a correlation between seismicity and surface manifestation of fluid circulation. Seismicity has a heterogeneous distribution: most of the earthquake are concentrated is the master NS-striking fault with fluid circulation manifestations; however along the segments without surface manifestation of fluids do not have seismicity. These results suggest that fluid circulation mostly occur in areas with high seismicity, and thus, the increment in fluid pressure enhances

Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

USGS Publications Warehouse

Waythomas, C.F.; Watts, P.; Walder, J.S.

2006-01-01

Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12-14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.

Space Radar Image of Colima Volcano, Jalisco, Mexico

NASA Image and Video Library

1999-05-01

This is an image of the Colima volcano in Jalisco, Mexico, a vigorously active volcano that erupted as recently as July 1994. The eruption partially destroyed a lava dome at the summit and deposited a new layer of ash on the volcano's southern slopes. Surrounding communities face a continuing threat of ash falls and volcanic mudflows from the volcano, which has been designated one of 15 high-risk volcanoes for scientific study during the next decade. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 24th orbit on October 1, 1994. The image is centered at 19.4 degrees north latitude, 103.7 degrees west longitude. The area shown is approximately 35.7 kilometers by 37.5 kilometers (22 miles by 23 miles). This single-frequency, multi-polarized SIR-C image shows: red as L-band horizontally transmitted and received; green as L-band horizontally transmitted and vertically received; and blue as the ratio of the two channels. The summit area appears orange and the recent deposits fill the valleys along the south and southwest slopes. Observations from space are helping scientists understand the behavior of dangerous volcanoes and will be used to mitigate the effects of future eruptions on surrounding populations. http://photojournal.jpl.nasa.gov/catalog/PIA01739

Biogeochemical interactions among the arsenic, iron, humic substances, and microbes in mud volcanoes in southern Taiwan.

PubMed

Liu, Chia-Chuan; Maity, Jyoti Prakash; Jean, Jiin-Shuh; Sracek, Ondra; Kar, Sandeep; Li, Zhaohui; Bundschuh, Jochen; Chen, Chien-Yen; Lu, Hsueh-Yu

2011-01-01

Fluid and mud samples collected from Hsiaokunshui (HKS), Wushanting (WST), Yenshuikeng (YSK), Kunshuiping (KSP), Liyushan (LYS), and Sinyangnyuhu (SYNH) mud volcanoes of southwestern Taiwan were characterized for major ions, humic substances (HS) and trace elements concentrations. The relationship between the release of arsenic (As) and activities of sulfate-reducing bacteria has been assessed to understand relevant geochemical processes in the mud volcanoes. Arsenic (0.02-0.06 mg/L) and humic substances (4.13 × 10(-4) to 1.64 × 10(-3) mM) in the fluids of mud volcanoes showed a positive correlation (r = 0.99, p < 0.05) except in Liyushan mud volcano. Arsenic and iron in mud sediments formed two separate groups i) high As, but low Fe in HKS, WST, and SYNH; and ii) low As, but high Fe in the YSK, KSP, and LYS mud volcanoes. The Eh(S.H.E.) values of the mud volcano liquids were characterized by mild to strongly reducing conditions. The HKS, SYNH, and WST mud volcanoes (near the Chishan Fault) belongs to strong reducing environment (-33 to -116 mV), whereas the LYS, YSK, and KSP mud volcanoes located near the coastal plain are under mild reducing environment (-11 to 172 mV). At low Eh values mud volcanoes, saturation index (SI) values of poorly crystalline phases such as amorphous ferric hydroxide indicate understaturation, whereas saturation is reached in relatively high Eh(S.H.E.) values mud volcanoes. Arsenic contents in sediments are low, presumably due to its release to fluids (As/Fe ratio in YSK, KSP, and LYS sediment: 4.86 × 10(-4)-6.20 × 10(-4)). At low Eh(S.H.E.) values (mild to strong reducing environment), arsenic may co-precipitate with sulfides as a consequence of sulfate reduction (As/Fe ratios in WST, HKS, and SYNH sediments: 0.42-0.69).

Timing of maximum glacial extent and deglaciation from HualcaHualca volcano (southern Peru), obtained with cosmogenic 36Cl.

NASA Astrophysics Data System (ADS)

Alcalá, Jesus; Palacios, David; Vazquez, Lorenzo; Juan Zamorano, Jose

2015-04-01

Andean glacial deposits are key records of climate fluctuations in the southern hemisphere. During the last decades, in situ cosmogenic nuclides have provided fresh and significant dates to determine past glacier behavior in this region. But still there are many important discrepancies such as the impact of Last Glacial Maximum or the influence of Late Glacial climatic events on glacial mass balances. Furthermore, glacial chronologies from many sites are still missing, such as HualcaHualca (15° 43' S; 71° 52' W; 6,025 masl), a high volcano of the Peruvian Andes located 70 km northwest of Arequipa. The goal of this study is to establish the age of the Maximum Glacier Extent (MGE) and deglaciation at HualcaHualca volcano. To achieve this objetive, we focused in four valleys (Huayuray, Pujro Huayjo, Mollebaya and Mucurca) characterized by a well-preserved sequence of moraines and roches moutonnées. The method is based on geomorphological analysis supported by cosmogenic 36Cl surface exposure dating. 36Cl ages have been estimated with the CHLOE calculator and were compared with other central Andean glacial chronologies as well as paleoclimatological proxies. In Huayuray valley, exposure ages indicates that MGE occurred ~ 18 - 16 ka. Later, the ice mass gradually retreated but this process was interrupted by at least two readvances; the last one has been dated at ~ 12 ka. In the other hand, 36Cl result reflects a MGE age of ~ 13 ka in Mollebaya valley. Also, two samples obtained in Pujro-Huayjo and Mucurca valleys associated with MGE have an exposure age of 10-9 ka, but likely are moraine boulders affected by exhumation or erosion processes. Deglaciation in HualcaHualca volcano began abruptly ~ 11.5 ka ago according to a 36Cl age from a polished and striated bedrock in Pujro Huayjo valley, presumably as a result of reduced precipitation as well as a global increase of temperatures. The glacier evolution at HualcaHualca volcano presents a high correlation with

A thick lens of fresh groundwater in the southern Lihue Basin, Kauai, Hawaii, USA

USGS Publications Warehouse

Izuka, S.K.; Gingerich, S.B.

2003-01-01

A thick lens of fresh groundwater exists in a large region of low permeability in the southern Lihue Basin, Kauai, Hawaii, USA. The conventional conceptual model for groundwater occurence in Hawaii and other shield-volcano islands does not account for such a thick freshwater lens. In the conventional conceptual model, the lava-flow accumulations of which most shield volcanoes are built form large regions of relatively high permeability and thin freshwater lenses. In the southern Lihue Basin, basin-filling lavas and sediments form a large region of low regional hydraulic conductivity, which, in the moist climate of the basin, is saturated nearly to the land surface and water tables are hundreds of meters above sea level within a few kilometers from the coast. Such high water levels in shield-volcano islands were previously thought to exist only under perched or dike-impounded conditions, but in the southern Lihue Basin, high water levels exist in an apparently dike-free, fully saturated aquifer. A new conceptual model of groundwater occurrence in shield-volcano islands is needed to explain conditions in the southern Lihue Basin.

Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies

NASA Astrophysics Data System (ADS)

Prezzi, Claudia; Risso, Corina; Orgeira, María Julia; Nullo, Francisco; Sigismondi, Mario E.; Margonari, Liliana

2017-08-01

The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llancanelo volcanic field, particularly in Las Bombas volcano. Las Bombas volcano is an eroded, but still recognizable, scoria cone located in a circular depression surrounded by a basaltic lava flow, suggesting that Las Bombas volcano was there when the lava flow field formed and, therefore, the lava flow engulfed it completely. While this explanation seems reasonable, the common presence of similar landforms in this part of the field justifies the need to establish correctly the stratigraphic relationship between lava flow fields and these circular depressions. The main purpose of this research is to investigate Las Bombas volcano 3D subsurface architecture by means of geophysical methods. We carried out a paleomagnetic study and detailed topographic, magnetic and gravimetric land surveys. Magnetic anomalies of normal and reverse polarity and paleomagnetic results point to the occurrence of two different volcanic episodes. A circular low Bouguer anomaly was detected beneath Las Bombas scoria cone indicating the existence of a mass deficit. A 3D forward gravity model was constructed, which suggests that the mass deficit would be related to the presence of fracture zones below Las Bombas volcano cone, due to sudden degassing of younger magma beneath it, or to a single phreatomagmatic explosion. Our results provide new and detailed information about Las Bombas volcano subsurface architecture.

Application of the Landsat Thematic Mapper to the identification of potentially active volcanoes in the Central Andes

NASA Technical Reports Server (NTRS)

Francis, P. W.; De Silva, S. L.

1989-01-01

A systematic study of the potentially active volcanoes in the Central Andes (14 deg S to 28 deg S) was carried out on the basis of Landsat Thematic Mapper images which provided consistent coverage of the area. More than 60 major volcanoes were identified as potentially active, as compared to 16 that are listed in the Catalog of Active Volcanoes of the World (Casertano, 1963; Hantke and Parodi, 1966). Most of these volcanoes are large (up to 6000 m in height) composite cones. Some of them could threaten nearby settlements, especially those in southern Peru, where the volcanoes rise above deep canyons with settlements along them.

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

PubMed Central

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

2014-01-01

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. PMID:24812211

3-D Resistivity Structure of La Soufrière Volcano (Guadeloupe): New Insights into the Hydrothermal System and Associated Hazards

NASA Astrophysics Data System (ADS)

Rosas-Carbajal, M.; Nicollin, F.; Komorowski, J. C.; Gibert, D.; Deroussi, S.

2015-12-01

The 3-D electrical resistivity model of the dome of La Soufrière of Guadeloupe volcano was obtained by inverting more than 23000 electrical resistivity tomography (ERT) and mise-a-la-masse data points. Data acquisition involved 2-D and 3-D protocols, including several pairs of injection electrodes located on opposite sides of the volcano. For the mise-a-la-masse measurements, the contact with a conductive mass was achieved by immersing one of the current electrodes in the Tarissan acid pond (~25 Siemens/m) located in the volcano's summit. The 3-D inversion was performed using a deterministic smoothness-constrained least-squares algorithm with unstructured grid modeling to accurately account for topography. Resistivity contrasts of more than 4 orders of magnitude are observed. A thick and high-angle conductive structure is located in the volcano's southern flank. It extends from the Tarissan Crater's acid pond on the summit to a hot spring region located close to the dome's southern base. This suggests that a large hydrothermal reservoir is located below the southern base of the dome, and connected to the acid pond of the summit's main crater. Therefore, the steep southern flanks of the volcano could be resting on a low-strength, high-angle discontinuity saturated with circulating and possibly pressurized hydrothermal fluids. This could favor partial edifice collapse and lateral directed explosions as shown recurrently in the volcano's history. The resistivity model also reveals smaller hydrothermal reservoirs in the south-east and northern flanks that are linked to the main historical eruptive fractures and to ancient collapse structures such as the Cratère Amic structure. We discuss the main resistivity structures in relation with the geometry of observed faults, historical eruptive fractures, the dynamics of the near surface hydrothermal system manifestations on the dome and the potential implications for future hazards scenarios .

Ionospheric "Volcanology": Ionospheric Detection of Volcano Eruptions

NASA Astrophysics Data System (ADS)

Astafyeva, E.; Shults, K.; Lognonne, P. H.; Rakoto, V.

2016-12-01

It is known that volcano eruptions and explosions can generate acoustic and gravity waves. These neutral waves further propagate into the atmosphere and ionosphere, where they are detectable by atmospheric and ionospheric sounding tools. So far, the features of co-volcanic ionospheric perturbations are not well understood yet. The development of the global and regional networks of ground-based GPS/GNSS receivers has opened a new era in the ionospheric detection of natural hazard events, including volcano eruptions. It is now known that eruptions with the volcanic explosivity index (VEI) of more than 2 can be detected in the ionosphere, especially in regions with dense GPS/GNSS-receiver coverage. The co-volcanic ionospheric disturbances are usually characterized as quasi-periodic oscillations. The Calbuco volcano, located in southern Chile, awoke in April 2015 after 43 years of inactivity. The first eruption began at 21:04UT on 22 April 2015, preceded by only an hour-long period of volcano-tectonic activity. This first eruption lasted 90 minutes and generated a sub-Plinian (i.e. medium to large explosive event), gray ash plume that rose 15 km above the main crater. A larger second event on 23 April began at 04:00UT (01:00LT), it lasted six hours, and also generated a sub-Plinian ash plume that rose higher than 15 km. The VEI was estimated to be 4 to 5 for these two events. In this work, we first study ionospheric TEC response to the Calbuco volcano eruptions of April 2015 by using ground-based GNSS-receivers located around the volcano. We analyze the spectral characteristics of the observed TEC variations and we estimate the propagation speed of the co-volcanic ionospheric perturbations. We further proceed with the normal mode summation technique based modeling of the ionospheric TEC variations due to the Calbuco volcano eruptions. Finally, we attempt to localize the position of the volcano from the ionospheric measurements, and we also estimate the time of the

A Late Holocene explosive mafic eruption of Villarrica volcano, Southern Andes: The Chaimilla deposit

NASA Astrophysics Data System (ADS)

Costantini, L.; Pioli, L.; Bonadonna, C.; Clavero, J.; Longchamp, C.

2011-03-01

batches with distinct pre-eruptive degassing and rising histories. Our eruption conceptual model implies the arrival of new magma (represented in the deposit by P1 clasts) into a small, outgassed magma body which was accumulated at shallow level (mainly represented by P2 clasts). A new Chaimilla-type eruption could significantly affect the communities that have recently developed around Villarrica volcano and subsist mainly on tourism and forestry. As a result, a better understanding of the dynamics and evolution of the Chaimilla eruption is necessary for the identification of potential hazard scenarios at Villarrica volcano and, ultimately, for the risk mitigation of this populated area of Southern Chile.

Volcano-tectonic interactions at Sabancaya and other Peruvian volcanoes revealed by InSAR and seismicity

NASA Astrophysics Data System (ADS)

Jay, J.; Pritchard, M. E.; Aron, F.; Delgado, F.; Macedo, O.; Aguilar, V.

2013-12-01

southeast. We investigate a possible relationship between the seismicity and the subsidence and find that the swarm generates a stress field which may encourage the opening of fractures oriented parallel to both the elongation of the subsidence signal and the trend of regional faults. Thus, we hypothesize that the Ticsani swarm triggered the subsidence to the southeast by allowing migration of hydrothermal fluids through cracks, similar to the volcanic subsidence observed in southern Chile following the 2010 Maule earthquake and in Japan following the 2011 Tohoku earthquake, though other explanations for the subsidence cannot be ruled out. A noteworthy null result of our InSAR survey is the lack of deformation at Ubinas volcano, one of the most active volcanoes in Peru, even spanning its 2006 eruption.

Methanogenic calcite, 13C-depleted bivalve shells, and gas hydrate from a mud volcano offshore southern California

USGS Publications Warehouse

Hein, J.R.; Normark, W.R.; McIntyre, B.R.; Lorenson, T.D.; Powell, C.L.

2006-01-01

Methane and hydrogen sulfide vent from a cold seep above a shallowly buried methane hydrate in a mud volcano located 24 km offshore southern California in?? 800 m of water. Bivalves, authigenic calcite, and methane hydrate were recovered in a 2.1 m piston core. Aragonite shells of two bivalve species are unusually depleted in 13C (to -91??? ??13C), the most 13C-depleted shells of marine macrofauna yet discovered. Carbon isotopes for both living and dead specimens indicate that they used, in part, carbon derived from anaerobically oxidized methane to construct their shells. The ??13C values are highly variable, but most are within the range -12??? to -91???. This variability may be diagnostic for identifying cold-seep-hydrate systems in the geologic record. Authigenic calcite is abundant in the cores down to ???1.5 m subbottom, the top of the methane hydrate. The calcite is depleted in 13C (??13C = -46??? to -58???), indicating that carbon produced by anaerobically oxidized methane is the main source of the calcite. Methane sources include a geologic hydrocarbon reservoir from Miocene source rocks, and biogenic and thermogenic degradation of organic matter in basin sediments. Oxygen isotopes indicate that most calcite formed out of isotopic equilibrium with ambient bottom water, under the influence of gas hydrate dissociation and strong methane flux. High metal content in the mud volcano sediment indicates leaching of basement rocks by fluid circulating along an underlying fault, which also allows for a high flux of fossil methane. ?? 2006 Geological Society of America.

Observations at Kuchinoerabu-jima volcano, southern Kyushu, Japan, by using unmanned helicopter

NASA Astrophysics Data System (ADS)

Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Kanda, W.; Tameguri, T.; Kazahaya, R.

2015-12-01

Kuchinoerabu-jima, volcano is a volcanic island located southern Kyushu, Japan. In 3 August, 2014, a small eruption at active summit crater, Shin-dake, destroyed all the observation stations near the summit. Since then, this volcano was only poorly monitored. After the eruption, entering within 2km from Shin-dake crater was strictly prohibited and thus it was impossible to fix summit stations on site. In April, 2015, we conducted seismic sensor installation by using unmanned helicopter (RMAX-G1 manufactured by Yamaha) so as to reestablish the seismic monitoring network near the summit area. We installed four seismic stations in the summit area. We also conducted various types of near-summit observations including an aero-magnetic measurement over the summit area, taking visual and infra-red images from low altitude, and volcanic gas sampling. We present preliminary results of the near summit observations using unmanned helicopter. The light-weight (5kg) and solar-powered seismic stations were designed exclusively for helicopter installation. They transmit seismic data every 10 minutes by using mobile data communication network. We could install them within 500m from the summit crater on 17, April. On 29 May, Shin-dake crater erupted again and the newly installed seismic stations were all destroyed by this eruption. The seismic stations could transmit data until just before the eruption. These data made us possible to evaluate the change in seismic activity leading up to the eruption. An aero-magnetic survey was conducted on 17 and 18 April. The flight altitude was between 100m and 150m above the ground (i.e a draped magnetic survey) . Path interval is 100m and the total flight path length is 80km. The magnetic intensity data were converted to magnetization of the edifice of Shin-dake. Comparison between the result this time with that obtained in 2001 shows demagnetization near the summit area. Temperature measurement over the summit area detected 368ºC　at the

A remote sensing assessment of the impact of the 2010 Maule, Chile earthquake (Mw 8.8) on the volcanoes of the southern Andes

NASA Astrophysics Data System (ADS)

Pritchard, M. E.; Welch, M.; Jay, J.; Button, N.

2011-12-01

There are tantalizing, but controversial, indications that great earthquakes affect arc-wide volcanic activity. For example, analysis of historic eruptions at volcanoes of the southern Andes has shown that 3-4 eruptions were likely seismically triggered by Mw > 8 earthquakes in the Chile subduction zone -- particularly the 1906 and 1960 earthquakes (e.g., Watt et al., 2009). However, the 27 February 2010 Mw 8.8 Maule, Chile earthquake that ruptured the subduction zone between the 1960 and 1906 earthquakes does not appear to have triggered 3-4 volcanic eruptions in the same area in the 12 months after the event. In an effort to understand the relation between a large earthquake and volcanic unrest, we use a variety of satellite instruments to look for more subtle (i.e., not leading to eruption), but detectable change in thermal or deformation activity at the volcanoes of the southern Andes after the Maule earthquake and its aftershocks. For all of the volcanoes in the catalog of the Smithsonian Institution (approximately 80), we use nighttime MODIS and ASTER data to assess the thermal activity and ALOS InSAR data to characterize the surface deformation before and after the earthquake. The ALOS InSAR data are not ideal for detecting changes in deformation before and after the earthquake because of the small number of acquisitions in austral summer as well as ionospheric and tropospheric artifacts. We estimate that we could detect deformation > 5 cm/year. Similarly, the ASTER and MODIS data suffer respectively from poor temporal and spatial resolution of thermal anomalies. We update previous InSAR work that identified at least 8 areas of volcanic deformation in the southern Andes related to eruptive processes, subsidence of past lava flows, or surface uplift not associated with an eruption (Fournier et al., 2010). Of greatest interest are the two volcanic areas with the largest deformation signals between 2007-2008 (both > 15 cm/yr in the radar line of sight): Laguna

A magmatic model of Medicine Lake Volcano, California ( USA).

USGS Publications Warehouse

Donnelly-Nolan, J. M.

1988-01-01

Medicine Lake volcano is a Pleistocene and Holocene shield volcano of the southern Cascade Range. It is located behind the main Cascade arc in an extensional tectonic setting where high-alumina basalt is the most commonly erupted lava. This basalt is parental to the higher-silica calc-alkaline and tholeiitic lavas that make up the bulk of the shield. The presence of late Holocene, chemically identical rhyolites on opposite sides of the volcano led to hypotheses of a large shallow silicic magma chamber and of a small, deep chamber that fed rhyolites to the surface via cone sheets. Subsequent geophysical work has been unable to identify a large silicic magma body, and instead a small one has apparently been recognized. Some geologic data support the geophysical results. Tectonic control of vent alignments and the dominance of mafic eruptions both in number of events and volume throughout the history of the volcano indicate that no large silicic magma reservoir exists. Instead, a model is proposed that includes numerous dikes, sills and small magma bodies, most of which are too small to be recognized by present geophysical methods.-Author

The Unexpected Awakening of Chaitén Volcano, Chile

NASA Astrophysics Data System (ADS)

Carn, Simon A.; Pallister, John S.; Lara, Luis; Ewert, John W.; Watt, Sebastian; Prata, Alfred J.; Thomas, Ronald J.; Villarosa, Gustavo

2009-06-01

On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [Guffanti et al., 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.

The Unexpected Awakening of Chaitén Volcano, Chile

USGS Publications Warehouse

Carn, Simon A.; Zogorski, John S.; Lara, Luis; Ewert, John W.; Watt, Sebastian; Prata, Alfred J.; Thomas, Ronald J.; Villarosa, Gustavo

2009-01-01

On 2 May 2008, a large eruption began unexpectedly at the inconspicuous Chaitén volcano in Chile's southern volcanic zone. Ash columns abruptly jetted from the volcano into the stratosphere, followed by lava dome effusion and continuous low-altitude ash plumes [Lara, 2009]. Apocalyptic photographs of eruption plumes suffused with lightning were circulated globally. Effects of the eruption were extensive. Floods and lahars inundated the town of Chaitén, and its 4625 residents were evacuated. Widespread ashfall and drifting ash clouds closed regional airports and cancelled hundreds of domestic flights in Argentina and Chile and numerous international flights [Guffanti et al., 2008]. Ash heavily affected the aquaculture industry in the nearby Gulf of Corcovado, curtailed ecotourism, and closed regional nature preserves. To better prepare for future eruptions, the Chilean government has boosted support for monitoring and hazard mitigation at Chaitén and at 42 other highly hazardous, active volcanoes in Chile.

Volcanoes in the pre-Columbian life, legend, and archaeology of Costa Rica (Central America)

NASA Astrophysics Data System (ADS)

Alvarado, Guillermo E.; Soto, Gerardo J.

2008-10-01

Costa Rica is located geographically in the southern part of the Central American Volcanic Front, a zone where interaction between the Mesoamerican and South American cultures occurred in pre-Columbian times. Several volcanoes violently erupted during the Holocene, when the first nomadic human hunters and later settlers were present. Volcanic rocks were the most important geo-resource in making artifacts and as construction materials for pre-Columbian inhabitants. Some pottery products are believed to resemble smoking volcanoes, and the settlements around volcanoes would seem to indicate their influence on daily life. Undoubtedly, volcanic eruptions disrupted the life of early settlers, particularly in the vicinity of Arenal and Irazú volcanoes, where archaeological remains show transient effects and displacement caused by periodical eruptions, but later resilient occupations around the volcanoes. Most native languages are extinct, with the exception of those presently spoken in areas far away from active volcanoes, where no words are related to volcanic phenomena or structures. The preserved legends are ambiguous, suggesting that they were either produced during the early Spanish conquest or were altered following the pre-Columbian period.

Volcano hazards at Newberry Volcano, Oregon

USGS Publications Warehouse

Sherrod, David R.; Mastin, Larry G.; Scott, William E.; Schilling, Steven P.

1997-01-01

Newberry volcano is a broad shield volcano located in central Oregon. It has been built by thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during several eruptive episodes of the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. The most-visited part of the volcano is Newberry Crater, a volcanic depression or caldera at the summit of the volcano. Seven campgrounds, two resorts, six summer homes, and two major lakes (East and Paulina Lakes) are nestled in the caldera. The caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Other eruptions during this time have occurred along a rift zone on the volcano's northwest flank and, to a lesser extent, the south flank. Many striking volcanic features lie in Newberry National Volcanic Monument, which is managed by the U.S. Forest Service. The monument includes the caldera and extends along the northwest rift zone to the Deschutes River. About 30 percent of the area within the monument is covered by volcanic products erupted during the past 10,000 years from Newberry volcano. Newberry volcano is presently quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. This report describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. In terms of our own lifetimes, volcanic events at Newberry are not of day-to-day concern because they occur so infrequently; however, the consequences of some types of eruptions can be severe. When Newberry

Comparison of flank modification on Ascraeus and Arsia Montes volcanoes, Mars

NASA Technical Reports Server (NTRS)

Zimbelman, James R.

1993-01-01

Geologic mapping of the Tharsis Montes on Mars is in progress as part of the Mars Geologic Mapping Program of NASA. Mapping of the southern flanks of Ascraeus Mons at 1:500,000 scale was undertaken first followed by detailed mapping of Arsia Mons; mapping of Pavonis Mons will begin later this year. Results indicate that each of the Tharsis volcanoes displays unique variations on the general 'theme' of a martian shield volcano. Here we concentrate on the flank characteristics on Ascraeus Mons and Arsia Mons, the northernmost and southernmost of the Tharsis Montes, as illustrative of the most prominent trends.

Interdisciplinary studies of eruption at Chaitén volcano, Chile

USGS Publications Warehouse

Pallister, John S.; Major, Jon J.; Pierson, Thomas C.; Holitt, Richard P.; Lowenstern, Jacob B.; Eichelberger, John C.; Luis, Lara; Moreno, Hugo; Muñoz, Jorge; Castro, Jonathan M.; Iroumé, Andrés; Andreoli, Andrea; Jones, Julia; Swanson, Fred; Crisafulli, Charlie

2010-01-01

High-silica rhyolite magma fuels Earth's largest and most explosive eruptions. Recurrence intervals for such highly explosive eruptions are in the 100- to 100,000-year time range, and there have been few direct observations of such eruptions and their immediate impacts. Consequently, there was keen interest within the volcanology community when the first large eruption of high-silica rhyolite since that of Alaska's Novarupta volcano in 1912 began on 1 May 2008 at Chaitén volcano, southern Chile, a 3-kilometer-diameter caldera volcano with a prehistoric record of rhyolite eruptions [Naranjo and Stern, 2004semi; Servicio Nacional de Geología y Minería (SERNAGEOMIN), 2008semi; Carn et al., 2009; Castro and Dingwell, 2009; Lara, 2009; Muñoz et al., 2009]. Vigorous explosions occurred through 8 May 2008, after which explosive activity waned and a new lava dome was extruded.

Mercury speciation, fluxes, and fate in the volcanically acidified fluids of Copahue volcano, Argentina

NASA Astrophysics Data System (ADS)

Kading, T.; Varekamp, J. C.; Andersson, M.; Balcom, P.; Mason, R. P.

2010-12-01

The behavior of mercury in volcanic acid springs and acidified rivers is poorly known, despite the potential impact this vector of contamination has on local surface and ground water quality. Mercury was measured in a volcanically acidified river system (pH<1 - 3), the Rio Agrio in the Neuquen province of Argentina, which discharges into a large glacial lake (Lake Caviahue, pH 2.2-3.0). The Hg concentration ranged from 2 - 600 pM throughout the fluvial system. Mercury in the hot, hyperacidic source fluids was dominated by dissolved ionic species, with only 2% of total mercury as dissolved elemental mercury, and 11% being particulate bound. The Hg flux from the volcano, determined from river water flux measurements and Hg concentrations, was modest and varied between the 3/2008 and 3/2009 sampling campaigns resp. from 0.7 to 1.1 moles/year. The Hg:S ratio of the acid fluids was ~10-8, several orders of magnitude lower than that typically found in volcanic plumes and fumaroles. The small Hg flux and low Hg:S values suggest that the system is either inherently Hg-poor or has lost Hg through vapor loss deeper in the hydrothermal system. Support for the latter comes from high Hg concentrations in geothermal vents and mudpots on the flank of the mountain (24 - 55 ppm Hg). Mercury concentrations decreased conservatively downstream in the river as based on Hg/Cl and Hg/SO4. Non-conservative depletion occurs in the less acidic Lake Caviahue, suggesting that mercury is removed from the water column by sorption to organic matter or other phases. Mercury analyses of a short lake sediment core confirm this (Hg = 0.01 to 0.70 ppm). No evidence was found for preferential uptake of mercury by jarosite, schwertmannite, or goethite, although the latter two phases precipitate in the most distal and Hg-depleted section of the fluvial system.

Volcanoes.

ERIC Educational Resources Information Center

Tilling, Robert I.

One of a series of general interest publications on science topics, this booklet provides a non-technical introduction to the subject of volcanoes. Separate sections examine the nature and workings of volcanoes, types of volcanoes, volcanic geological structures such as plugs and maars, types of eruptions, volcanic-related activity such as geysers…

Managing the effects of accelerated glacial melting on volcanic collapse and debris flows: Planchon-Peteroa Volcano, Southern Andes

NASA Astrophysics Data System (ADS)

Tormey, Daniel

2010-11-01

Glaciated mountains are among the most sensitive environments to climatic changes, and recent work has shown that large-scale glacial melting, including at the end of the Pleistocene, caused a significant increase in the incidence of large volcanic sector collapse and debris flows on then-active volcanoes. With current accelerated rates of glacial melting, glaciated active volcanoes are at an increasing risk of sector collapse, debris flow and landslide. These catastrophic events are Earth's most damaging erosion phenomenon, causing extensive property damage and loss of life. This paper illustrates these effects in well-studied settings, focusing on the end-Pleistocene to Holocene glaciovolcanic growth and destruction of the cone of the active volcano Planchon-Peteroa in the Andean Southern Volcanic Zone at latitude 35° 15' S, along the border between Chile and Argentina. The development of the volcano over the last 14,000 years illustrates how glacial melting and magmatic activity can trigger landslides and sector collapses. Planchon had a large sector collapse that produced a highly mobile and erosive debris avalanche 11,000 years BP, and other slope instabilities during the end-Pleistocene/early Holocene deglaciation. The summit amphitheater left after the sector collapse was subject to alternating periods of glaciation and melting-induced lake formation. Breaching of the moraine dams then formed lahars and landslides originating at the western edge of the summit amphitheater, and the deposits are preserved along the western flank of the volcano. Deep incision of moraine deposits further down the western slope of the volcano indicates that the lahars and landslides were water-rich and had high erosive power. As illustrated by Planchon-Peteroa, the interplay among glacial growth and melting, magmatic activity, and slope stability is complex, but must be accounted for in volcanic hazard assessment. Planchon-Peteroa currently has the southernmost temperate zone

New geophysical views of Mt.Melbourne Volcano (East Antarctica)

NASA Astrophysics Data System (ADS)

Armadillo, E.; Gambetta, M.; Ferraccioli, F.; Corr, H.; Bozzo, E.

2009-05-01

Mt. Melbourne volcano is located along the transition between the Transantarctic Mountains and the West Antarctic Rift System. Recent volcanic activity is suggested by the occurrence of blankets of pyroclastic pumice and scoria fall around the eastern and southern flanks of Mt Melbourne and by pyroclastic layers interbedded with the summit snows. Geothermal activity in the crater area of Mount Melbourne may be linked to the intrusion of dykes within the last 200 years. Geophysical networks suggest that Mount Melbourne is a quiescent volcano, possibly characterised by slow internal dynamics. During the 2002-2003 Italian Antarctic campaign a high-resolution aeromagnetic survey was performed within the TIMM (Tectonics and Interior of Mt. Melbourne area) project. This helicopter-borne survey was flown at low-altitude and in drape-mode configuration (305 m above terrain) with a line separation less than 500 m. Our new high-resolution magnetic maps reveal the largely ice-covered magmatic and tectonic patters in the Mt. Melbourne volcano area. Additionally, in the frame of the UK-Italian ISODYN-WISE project (2005-06), an airborne ice-sounding radar survey was flown. We combine the sub-ice topography with images and models of the interior of Mt. Melbourne volcano, as derived from the high resolution aeromagnetic data and land gravity data. Our new geophysical maps and models also provide a new tool to study the regional setting of the volcano. In particular we re-assess whether there is geophysical evidence for coupling between strike-slip faulting, the Terror Rift, and Mount Melbourne volcano.

Volcano Hazards Program

USGS Publications Warehouse

Venezky, Dina Y.; Myers, Bobbie; Driedger, Carolyn

2008-01-01

Diagram of common volcano hazards. The U.S. Geological Survey Volcano Hazards Program (VHP) monitors unrest and eruptions at U.S. volcanoes, assesses potential hazards, responds to volcanic crises, and conducts research on how volcanoes work. When conditions change at a monitored volcano, the VHP issues public advisories and warnings to alert emergency-management authorities and the public. See http://volcanoes.usgs.gov/ to learn more about volcanoes and find out what's happening now.

Volcano-tectonic structures and CO2-degassing patterns in the Laacher See basin, Germany

NASA Astrophysics Data System (ADS)

Goepel, Andreas; Lonschinski, Martin; Viereck, Lothar; Büchel, Georg; Kukowski, Nina

2015-07-01

The Laacher See Volcano is the youngest (12,900 year BP) eruption center of the Quarternary East-Eifel Volcanic Field in Germany and has formed Laacher See, the largest volcanic lake in the Eifel area. New bathymetric data of Laacher See were acquired by an echo sounder system and merged with topographic light detection and ranging (LiDAR) data of the Laacher See Volcano area to form an integrated digital elevation model. This model provides detailed morphological information about the volcano basin and results of sediment transport therein. Morphological analysis of Laacher See Volcano indicates a steep inner crater wall (slope up to 30°) which opens to the south. The Laacher See basin is divided into a deep northern and a shallower southern part. The broader lower slopes inclined with up to 25° change to the almost flat central part (maximum water depth of 51 m) with a narrow transition zone. Erosion processes of the crater wall result in deposition of volcaniclastics as large deltas in the lake basin. A large subaqueous slide was identified at the northeastern part of the lake. CO2-degassing vents (wet mofettes) of Laacher See were identified by a single-beam echo sounder system through gas bubbles in the water column. These are more frequent in the northern part of the lake, where wet mofettes spread in a nearly circular-shaped pattern, tracing the crater rim of the northern eruption center of the Laacher See Volcano. Additionally, preferential paths for gas efflux distributed concentrically inside the crater rim are possibly related to volcano-tectonic faults. In the southern part of Laacher See, CO2 vents occur in a high spatial density only within the center of the arc-shaped structure Barschbuckel possibly tracing the conduit of a tuff ring.

Neotectonics in the foothills of the southernmost central Andes (37°-38°S): Evidence of strike-slip displacement along the Antiñir-Copahue fault zone

NASA Astrophysics Data System (ADS)

Folguera, AndréS.; Ramos, VíCtor A.; Hermanns, Reginald L.; Naranjo, José

2004-10-01

The Antiñir-Copahue fault zone (ACFZ) is the eastern orogenic front of the Andes between 38° and 37°S. It is formed by an east vergent fan of high-angle dextral transpressive and transtensive faults, which invert a Paleogene intra-arc rift system in an out of sequence order with respect to the Cretaceous to Miocene fold and thrust belt. 3.1-1.7 Ma volcanic rocks are folded and fractured through this belt, and recent indicators of fault activity in unconsolidated deposits suggest an ongoing deformation. In spite of the absence of substantial shallow seismicity associated with the orogenic front, neotectonic studies show the existence of active faults in the present mountain front. The low shallow seismicity could be linked to the high volumes of retroarc-derived volcanic rocks erupted through this fault system during Pliocene and Quaternary times. This thermally weakened basement accommodates the strain of the Antiñir-Copahue fault zone, absorbing the present convergence between the South America and Nazca plates.

Hawaiian Volcano Observatory

USGS Publications Warehouse

Venezky, Dina Y.; Orr, Tim R.

2008-01-01

Lava from Kilauea volcano flowing through a forest in the Royal Gardens subdivision, Hawai'i, in February 2008. The Hawaiian Volcano Observatory (HVO) monitors the volcanoes of Hawai'i and is located within Hawaiian Volcanoes National Park. HVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Kilauea and HVO at http://hvo.wr.usgs.gov.

Evidence for dike emplacement beneath Iliamna Volcano, Alaska in 1996

USGS Publications Warehouse

Roman, D.C.; Power, J.A.; Moran, S.C.; Cashman, K.V.; Doukas, M.P.; Neal, C.A.; Gerlach, T.M.

2004-01-01

Two earthquake swarms, comprising 88 and 2833 locatable events, occurred beneath Iliamna Volcano, Alaska, in May and August of 1996. Swarm earthquakes ranged in magnitude from -0.9 to 3.3. Increases in SO2 and CO2 emissions detected during the fall of 1996 were coincident with the second swarm. No other physical changes were observed in or around the volcano during this time period. No eruption occurred, and seismicity and measured gas emissions have remained at background levels since mid-1997. Earthquake hypocenters recorded during the swarms form a cluster in a previously aseismic volume of crust located to the south of Iliamna's summit at a depth of -1 to 4 km below sea level. This cluster is elongated to the NNW-SSE, parallel to the trend of the summit and southern vents at Iliamna and to the regional axis of maximum compressive stress determined through inversion of fault-plane solutions for regional earthquakes. Fault-plane solutions calculated for 24 swarm earthquakes located at the top of the new cluster suggest a heterogeneous stress field acting during the second swarm, characterized by normal faulting and strike-slip faulting with p-axes parallel to the axis of regional maximum compressive stress. The increase in earthquake rates, the appearance of a new seismic volume, and the elevated gas emissions at Iliamna Volcano indicate that new magma intruded beneath the volcano in 1996. The elongation of the 1996-1997 earthquake cluster parallel to the direction of regional maximum compressive stress and the accelerated occurrence of both normal and strike-slip faulting in a small volume of crust at the top of the new seismic volume may be explained by the emplacement and inflation of a subvertical planar dike beneath the summit of Iliamna and its southern satellite vents. ?? 2003 Elsevier B.V. All rights reserved.

Preliminary volcano-hazard assessment for Kanaga Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Miller, Thomas P.; Nye, Christopher J.

2002-01-01

Kanaga Volcano is a steep-sided, symmetrical, cone-shaped, 1307 meter high, andesitic stratovolcano on the north end of Kanaga Island (51°55’ N latitude, 177°10’ W longitude) in the western Aleutian Islands of Alaska. Kanaga Island is an elongated, low-relief (except for the volcano) island, located about 35 kilometers west of the community of Adak on Adak Island and is part of the Andreanof Islands Group of islands. Kanaga Volcano is one of the 41 historically active volcanoes in Alaska and has erupted numerous times in the past 11,000 years, including at least 10 eruptions in the past 250 years (Miller and others, 1998). The most recent eruption occurred in 1993-95 and caused minor ash fall on Adak Island and produced blocky aa lava flows that reached the sea on the northwest and west sides of the volcano (Neal and others, 1995). The summit of the volcano is characterized by a small, circular crater about 200 meters in diameter and 50-70 meters deep. Several active fumaroles are present in the crater and around the crater rim. The flanking slopes of the volcano are steep (20-30 degrees) and consist mainly of blocky, linear to spoonshaped lava flows that formed during eruptions of late Holocene age (about the past 3,000 years). The modern cone sits within a circular caldera structure that formed by large-scale collapse of a preexisting volcano. Evidence for eruptions of this preexisting volcano mainly consists of lava flows exposed along Kanaton Ridge, indicating that this former volcanic center was predominantly effusive in character. In winter (October-April), Kanaga Volcano may be covered by substantial amounts of snow that would be a source of water for lahars (volcanic mudflows). In summer, much of the snowpack melts, leaving only a patchy distribution of snow on the volcano. Glacier ice is not present on the volcano or on other parts of Kanaga Island. Kanaga Island is uninhabited and is part of the Alaska Maritime National Wildlife Refuge, managed by

Manam Volcano, Papua New Guinea

NASA Image and Video Library

2017-12-08

NASA image acquired June 16, 2010. Papua New Guinea’s Manam Volcano released a thin, faint plume on June 16, 2010, as clouds clustered at the volcano’s summit. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite took this picture the same day. Rivulets of brown rock interrupt the carpet of green vegetation on the volcano’s slopes. Opaque white clouds partially obscure the satellite’s view of Manam. The clouds may result from water vapor from the volcano, but may also have formed independent of volcanic activity. The volcanic plume appears as a thin, blue-gray veil extending toward the northwest over the Bismarck Sea. Located 13 kilometers (8 miles) off the coast of mainland Papua New Guinea, Manam forms an island 10 kilometers (6 miles) wide. It is a stratovolcano. The volcano has two summit craters, and although both are active, most historical eruptions have arisen from the southern crater. NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott. Instrument: EO-1 - ALI To view the full image go to: earthobservatory.nasa.gov/NaturalHazards/view.php?id=4430... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Preliminary volcano-hazard assessment for Iliamna Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Miller, Thomas P.

1999-01-01

Iliamna Volcano is a 3,053-meter-high, ice- and snow-covered stratovolcano in the southwestern Cook Inlet region about 225 kilometers southwest of Anchorage and about 100 kilometers northwest of Homer. Historical eruptions of Iliamna Volcano have not been positively documented; however, the volcano regularly emits steam and gas, and small, shallow earthquakes are often detected beneath the summit area. The most recent eruptions of the volcano occurred about 300 years ago, and possibly as recently as 90-140 years ago. Prehistoric eruptions have generated plumes of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. Rock avalanches from the summit area have occurred numerous times in the past. These avalanches flowed several kilometers down the flanks and at least two large avalanches transformed to cohesive lahars. The number and distribution of known volcanic ash deposits from Iliamna Volcano indicate that volcanic ash clouds from prehistoric eruptions were significantly less voluminous and probably less common relative to ash clouds generated by eruptions of other Cook Inlet volcanoes. Plumes of volcanic ash from Iliamna Volcano would be a major hazard to jet aircraft using Anchorage International Airport and other local airports, and depending on wind direction, could drift at least as far as the Kenai Peninsula and beyond. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Because Iliamna Volcano has not erupted for several hundred years, a future eruption could involve significant amounts of ice and snow that could lead to the formation of large lahars and downstream flooding. The greatest hazards in order of importance are described below and shown on plate 1.

Estimation of Seismic Attenuation beneath Tateyama Volcano, Central Japan by Using Peak Delay

NASA Astrophysics Data System (ADS)

Iwata, K.; Kawakata, H.; Hirano, S.; Doi, I.

2015-12-01

The Hida Mountain Range located in central Japan has a lot of active volcanoes. Katsumata et al. (1995, GJI) suggested the presence of regions with low-velocity and low-density as well as low Qanomaly at 5-15 km deep beneath the range. Tateyama volcano is located in the northern part of the range. Iwata et al. (2014, AGU Fall Meeting) quantitatively estimated strength of S-wave attenuation beneath Tateyama volcano using twofold spectral ratios and suggested that regions with high seismic attenuation exist in the south or the southeast of Tateyama volcano. However, it is difficult to estimate the contribution of scattering loss and intrinsic absorption to total attenuation on the basis of this method. In the present study, we focused on the peak delay (Takahashi et al., 2007, GJI) in seismic envelopes. We used seismograms observed at five NIED Hi-net stations near Tateyama volcano for 31 local earthquakes (MJMA2.5-4.0). We found seismograms recorded after passing below the southern part of the Hida Mountain Range show longer peak delay than those recorded before passing below the region, while there are no clear difference in peak delay for pairs of seismograms before and after passing below Tateyama volcano. It suggests that causes of the attenuation beneath Tateyama volcano and the southern part of the Hida Mountain Range are different. We used the peak delay values to evaluate the strength of intrinsic absorption. We assumed that the difference of whole peak delay between two seismograms for the same earthquake was caused by intrinsic absorption beneath the region between the two seismic stations. Wecalculated the change in amplitude and peak delay on the basis of a theory suggested by Azimi et al. (1966, Izvestia, Earth Physics). In case of the two envelopes are quite similar to each other, we conclude that intrinsic absorption is a major cause of total attenuation

Space radar image of Galeras Volcano, Colombia

NASA Technical Reports Server (NTRS)

1995-01-01

This radar image of the area surrounding the Galeras volcano in southern Colombia shows the ability of a multi-frequency radar to map volcanic structures that can be dangerous to study on the ground. Galeras has erupted more than 20 times since the area was first visited by European explorers in the 1500s. Volcanic activity levels have been high in the last five years, including an eruption in January 1993 that killed nine people on a scientific expedition to the volcano summit. Galeras is the light green area near the center of the image. The active cone, with a small summit pit, is the red feature nestled against the lower right edge of the caldera (crater) wall. The city of Pasto, with a population of 300,000, is shown in orange near the bottom of the image, just 8 kilometers (5 miles) from the volcano. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/ X-SAR) aboard the space shuttle Endeavour on its 96th orbit on April 15, 1994. North is toward the upper right. The area shown is 49.1 by 36.0 kilometers (30.5 by 22.3 miles), centered at 1.2 degrees north latitude and 77.4 degrees west longitude. The radar illumination is from the top of the image. The false colors in this image were created using the following radar channels: red represents the L-band (horizontally transmitted and received); green represents the L-band (horizontally transmitted, vertically received); blue represents the C-band (horizontally transmitted, vertically received). Galeras is one of 15 volcanoes worldwide that are being monitored by the scientific community as an 'International Decade Volcano' because of the hazard that it represents to the local population.

Nicaraguan Volcanoes

Atmospheric Science Data Center

2013-04-18

article title:  Nicaraguan Volcanoes     View Larger Image Nicaraguan volcanoes, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya volcanoes. project:  MISR category:  gallery ...

Insights into the dynamics of Etna volcano from 20-year time span microgravity and GPS observations

NASA Astrophysics Data System (ADS)

Bonforte, Alessandro; Fanizza, Giovanni; Greco, Filippo; Matera, Alfredo; Sulpizio, Roberto

2016-04-01

A common ground deformation and microgravity array of benchmarks lies on the southern slope of Mt. Etna volcano and is routinely measured by GPS and relative gravimetry methods. The array was installed for monitoring the ground motion and underground mass changes along the southern rift of the volcano and data are usually processed and interpreted independently. The benchmarks have been installed mainly along a main road crossing the southern side of the volcano with an E-W direction and reaching 2000 m of altitude. The gravity array covers the entire path of the road, while the ground deformation one only the upper one, due to the woods at lower altitude preventing good GPS measurements. Furthermore, microgravity surveys are usually carried out more frequently with respect to the GPS ones. In this work, an integrated analysis of microgravity and ground deformation is performed over a 20-year time span (1994-2014). Gravity variations have been first corrected for the free-air effect using the GPS observed vertical deformation and the theoretical vertical gravity gradient (-308.6 μGal/m). The free-air corrected gravity changes were then reduced from the high frequency variations (noise) and the seasonal fluctuations, mainly due to water-table fluctuations. This long-term dataset constitutes a unique opportunity to examine the behavior of Etna in a period in which the volcano exhibited different styles of activity characterized by recharging phases, flank eruptions and fountaining episodes. The gravity and deformation data allow investigating the response of the volcano in a wider perspective providing insights into the definition of its dynamic behavior and posing the basis to track the unrest evolution and to forecast the style of the eruption. The joint analysis highlights common periods, in which the signals underwent contemporaneous changes occurring mainly in the central and eastern stations. On the other hand, no significant changes in the behavior of

Volcanoes

USGS Publications Warehouse

Tilling, Robert I.; ,

1998-01-01

Volcanoes destroy and volcanoes create. The catastrophic eruption of Mount St. Helens on May 18, 1980, made clear the awesome destructive power of a volcano. Yet, over a time span longer than human memory and record, volcanoes have played a key role in forming and modifying the planet upon which we live. More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequent erosion and weathering have sculpted into majestic landscapes and formed fertile soils.

Small Volcano in Terra Cimmeria

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 26 June 2002) The Science This positive relief feature (see MOLA context) in the ancient highlands of Mars appears to be a heavily eroded volcanic center. The top of this feature appears to be under attack by the erosive forces of the martian wind. Light-toned streaks are visible, trending northeast to southwest, and may be caused by scouring of the terrain, or they may be dune forms moving sand. The northeast portion of the caldera area looks as though a layer of material is being removed to expose a slightly lighter-toned surface underneath. The flanks of this feature are slightly less cratered than the surrounding terrain, which could be explained in two ways: 1) this feature may be younger than the surrounding area, and has had less time to accumulate meteorite impacts, or 2) the slopes that are observed today may be so heavily eroded that the original, cratered surfaces are now gone, exposing relatively uncratered rocks. Although most of Terra Cimmeria has low albedo, some eastern portions, such as shown in this image, demonstrate an overall lack of contrast that attests to the presence of a layer of dust mantling the surface. This dust, in part, is responsible for the muted appearance and infill of many of the craters at the northern and southern ends of this image The Story This flat-topped volcano pops out from the surface, the swirls of its ancient lava flows running down onto the ancient highlands of Mars. Its smooth top appears to be under attack by the erosive forces of the martian wind. How can you tell? Click on the image above for a close-up look. You'll see some light-toned streaks that run in a northeast-southwest direction. They are caused either by the scouring of the terrain or dunes of moving sand. Either way, the wind likely plays upon the volcano's surface. Look also for the subtle, nearly crescent shaped feature at the northeast portion of the volcano's cap. It looks as if a layer of material has been removed by the wind, exposing

Tephrochronology of the southernmost Andean Southern Volcanic Zone, Chile

NASA Astrophysics Data System (ADS)

Weller, D. J.; Miranda, C. G.; Moreno, P. I.; Villa-Martínez, R.; Stern, C. R.

2015-12-01

Correlations among and identification of the source volcanoes for over 60 Late Glacial and Holocene tephras preserved in eight lacustrine sediment cores taken from small lakes near Coyhaique, Chile (46° S), were made based on the stratigraphic position of the tephra in the cores, lithostratigraphic data (tephra layer thickness and grain size), and tephra petrochemistry (glass color and morphology, phenocryst phases, and bulk-tephra trace element contents determined by ICP-MS). The cores preserve a record of explosive eruptions, since ˜17,800 calibrated years before present (cal years BP), of the volcanoes of the southernmost Andean Southern Volcanic Zone (SSVZ). The suggested source volcanoes for 55 of these tephras include Hudson (32 events), Mentolat (10 events), and either Macá or Cay or some of the many minor monogenetic eruptive centers (MECs; 13 events) in the area. Only four of these eruptions had been previously identified in tephra outcrops in the region, indicating the value of lake cores for identifying smaller eruptions in tephrochronologic studies. The tephra records preserved in these lake cores, combined with those in marine cores, which extend these records back to 20,000 cal years BP, prior to the Last Glacial Maximum, suggest that no significant temporal change in the frequency of explosive eruptions was associated with deglaciation. Over this time period, Hudson volcano, one of the largest and longest lived volcanoes in the Southern Andes, has had >55 eruptions (four of them were very large) and has produced >45 km3 of pyroclastic material, making it also one of the most active volcanoes in the SVZ in terms of both frequency and volume of explosive eruptions.

Alaska Volcano Observatory

USGS Publications Warehouse

Venezky, Dina Y.; Murray, Tom; Read, Cyrus

2008-01-01

Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

Record of late holocene debris avalanches and lahars at Iliamna Volcano, Alaska

USGS Publications Warehouse

Waythomas, C.F.; Miller, T.P.; Beget, J.E.

2000-01-01

Iliamna Volcano is a 3053-meter high, glaciated stratovolcano in the southern Cook Inlet region of Alaska and is one of seven volcanoes in this region that have erupted multiple times during the past 10,000 yr. Prior to our studies of Iliamna Volcano, little was known about the frequency, magnitude, and character of Holocene volcanic activity. Here we present geologic evidence of the most recent eruptive activity of the volcano and provide the first outline of Late Holocene debris-avalanche and lahar formation. Iliamna has had no documented historical eruptions but our recent field investigations indicate that the volcano has erupted at least twice in the last 300 yr. Clay-rich lahar deposits dated by radiocarbon to ???1300 and ???90 yr BP are present in two major valleys that head on the volcano. These deposits indicate that at least two large, possibly deep-seated, flank failures of the volcanic edifice have occurred in the last 1300 yr. Noncohesive lahar deposits likely associated with explosive pyroclastic eruptions date to 2400-1300,>1500,???300, and <305 yr BP. Debris-avalanche deposits from recent and historical small-volume slope failures of the hydrothermally altered volcanic edifice cover most of the major glaciers on the volcano. Although these deposits consist almost entirely of hydrothermally altered rock debris and snow and ice, none of the recently generated debris avalanches evolved to lahars. A clay-rich lahar deposit that formed <90??60 radiocarbon yr BP and entered the Johnson River Valley southeast of the volcano cannot be confidently related to an eruption of Iliamna Volcano, which has had no known historical eruptions. This deposit may record an unheralded debris avalanche and lahar. ?? 2000 Elsevier Science B.V. All rights reserved.

Preliminary volcano-hazard assessment for Great Sitkin Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Miller, Thomas P.; Nye, Christopher J.

2003-01-01

Great Sitkin Volcano is a composite andesitic stratovolcano on Great Sitkin Island (51°05’ N latitude, 176°25’ W longitude), a small (14 x 16 km), circular volcanic island in the western Aleutian Islands of Alaska. Great Sitkin Island is located about 35 kilometers northeast of the community of Adak on Adak Island and 130 kilometers west of the community of Atka on Atka Island. Great Sitkin Volcano is an active volcano and has erupted at least eight times in the past 250 years (Miller and others, 1998). The most recent eruption in 1974 caused minor ash fall on the flanks of the volcano and resulted in the emplacement of a lava dome in the summit crater. The summit of the composite cone of Great Sitkin Volcano is 1,740 meters above sea level. The active crater is somewhat lower than the summit, and the highest point along its rim is about 1,460 meters above sea level. The crater is about 1,000 meters in diameter and is almost entirely filled by a lava dome emplaced in 1974. An area of active fumaroles, hot springs, and bubbling hot mud is present on the south flank of the volcano at the head of Big Fox Creek (see the map), and smaller ephemeral fumaroles and steam vents are present in the crater and around the crater rim. The flanking slopes of the volcano are gradual to steep and consist of variously weathered and vegetated blocky lava flows that formed during Pleistocene and Holocene eruptions. The modern edifice occupies a caldera structure that truncates an older sequence of lava flows and minor pyroclastic rocks on the east side of the volcano. The eastern sector of the volcano includes the remains of an ancestral volcano that was partially destroyed by a northwest-directed flank collapse. In winter, Great Sitkin Volcano is typically completely snow covered. Should explosive pyroclastic eruptions occur at this time, the snow would be a source of water for volcanic mudflows or lahars. In summer, much of the snowpack melts, leaving only a patchy

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Müller, Anne; Scharf, Burkhard; von Tümpling, Wolf; Pirrung, Michael

2009-03-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout as well as from river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue Volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (Lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Mueller, A.; Pirrung, M.; Scharf, B.; von Tuempling, W.

2007-05-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout, river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Volcanoes

MedlinePlus

... Oregon have the most active volcanoes, but other states and territories have active volcanoes, too. A volcanic eruption may involve lava and other debris that can flow up to 100 mph, destroying everything in their ...

Instrumentation Recommendations for Volcano Monitoring at U.S. Volcanoes Under the National Volcano Early Warning System

USGS Publications Warehouse

Moran, Seth C.; Freymueller, Jeff T.; LaHusen, Richard G.; McGee, Kenneth A.; Poland, Michael P.; Power, John A.; Schmidt, David A.; Schneider, David J.; Stephens, George; Werner, Cynthia A.; White, Randall A.

2008-01-01

As magma moves toward the surface, it interacts with anything in its path: hydrothermal systems, cooling magma bodies from previous eruptions, and (or) the surrounding 'country rock'. Magma also undergoes significant changes in its physical properties as pressure and temperature conditions change along its path. These interactions and changes lead to a range of geophysical and geochemical phenomena. The goal of volcano monitoring is to detect and correctly interpret such phenomena in order to provide early and accurate warnings of impending eruptions. Given the well-documented hazards posed by volcanoes to both ground-based populations (for example, Blong, 1984; Scott, 1989) and aviation (for example, Neal and others, 1997; Miller and Casadevall, 2000), volcano monitoring is critical for public safety and hazard mitigation. Only with adequate monitoring systems in place can volcano observatories provide accurate and timely forecasts and alerts of possible eruptive activity. At most U.S. volcanoes, observatories traditionally have employed a two-component approach to volcano monitoring: (1) install instrumentation sufficient to detect unrest at volcanic systems likely to erupt in the not-too-distant future; and (2) once unrest is detected, install any instrumentation needed for eruption prediction and monitoring. This reactive approach is problematic, however, for two reasons. 1. At many volcanoes, rapid installation of new ground-1. based instruments is difficult or impossible. Factors that complicate rapid response include (a) eruptions that are preceded by short (hours to days) precursory sequences of geophysical and (or) geochemical activity, as occurred at Mount Redoubt (Alaska) in 1989 (24 hours), Anatahan (Mariana Islands) in 2003 (6 hours), and Mount St. Helens (Washington) in 1980 and 2004 (7 and 8 days, respectively); (b) inclement weather conditions, which may prohibit installation of new equipment for days, weeks, or even months, particularly at

Volcanoes

ERIC Educational Resources Information Center

Kunar, L. N. S.

1975-01-01

Describes the forces responsible for the eruptions of volcanoes and gives the physical and chemical parameters governing the type of eruption. Explains the structure of the earth in relation to volcanoes and explains the location of volcanic regions. (GS)

Digital Data for Volcano Hazards at Newberry Volcano, Oregon

USGS Publications Warehouse

Schilling, S.P.; Doelger, S.; Sherrod, D.R.; Mastin, L.G.; Scott, W.E.

2008-01-01

Newberry volcano is a broad shield volcano located in central Oregon, the product of thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. Newberry Crater, a volcanic depression or caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Newberry National Volcanic Monument, which is managed by the U.S. Forest Service, includes the caldera and extends to the Deschutes River. Newberry volcano is quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. The report USGS Open-File Report 97-513 (Sherrod and others, 1997) describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. When Newberry volcano becomes restless, the eruptive scenarios described herein can inform planners, emergency response personnel, and citizens about the kinds and sizes of events to expect. The geographic information system (GIS) volcano hazard data layers used to produce the Newberry volcano hazard map in USGS Open-File Report 97-513 are included in this data set. Scientists at the USGS Cascades Volcano Observatory created a GIS data layer to depict zones subject to the effects of an explosive pyroclastic eruption (tephra fallout, pyroclastic flows, and ballistics), lava flows, volcanic gasses, and lahars/floods in Paulina Creek. A separate GIS data layer depicts drill holes on the flanks of Newberry Volcano that were used to estimate the probability

Assessment of pre-crisis and syn-crisis seismic hazard at Campi Flegrei and Mt. Vesuvius volcanoes, Campania, southern Italy

NASA Astrophysics Data System (ADS)

Convertito, Vincenzo; Zollo, Aldo

2011-08-01

In this study, we address the issue of short-term to medium-term probabilistic seismic hazard analysis for two volcanic areas, Campi Flegrei caldera and Mt. Vesuvius in the Campania region of southern Italy. Two different phases of the volcanic activity are considered. The first, which we term the pre-crisis phase, concerns the present quiescent state of the volcanoes that is characterized by low-to-moderate seismicity. The second phase, syn-crisis, concerns the unrest phase that can potentially lead to eruption. For the Campi Flegrei case study, we analyzed the pattern of seismicity during the 1982-1984 ground uplift episode (bradyseism). For Mt. Vesuvius, two different time-evolutionary models for seismicity were adopted, corresponding to different ways in which the volcano might erupt. We performed a site-specific analysis, linked with the hazard map, to investigate the effects of input parameters, in terms of source geometry, mean activity rate, periods of data collection, and return periods, for the syn-crisis phase. The analysis in the present study of the pre-crisis phase allowed a comparison of the results of probabilistic seismic hazard analysis for the two study areas with those provided in the Italian national hazard map. For the Mt. Vesuvius area in particular, the results show that the hazard can be greater than that reported in the national hazard map when information at a local scale is used. For the syn-crisis phase, the main result is that the data recorded during the early months of the unrest phase are substantially representative of the seismic hazard during the whole duration of the crisis.

GlobVolcano: Earth Observation Services for Global Monitroing of Active Volcanoes

NASA Astrophysics Data System (ADS)

Borgstrom, S.; Bianchi, M.; Bronson, W.; Tampellini, M. L.; Ratti, R.; Seifert, F. M.; Komorowski, J. C.; Kaminski, E.; Peltier, A.; Van der Voet, P.

2010-03-01

The GlobVolcano project (2007-2010) is part of the Data User Element (DUE) programme of the European Space Agency (ESA).The objective of the project is to demonstrate EO-based (Earth Observation) services able to support the Volcano Observatories and other mandate users (Civil Protection, volcano scientific community) in their monitoring activities.The set of offered EO based information products is the following:- Deformation Mapping- Surface Thermal Anomalies- Volcanic Gas Emission- Volcanic Ash TrackingThe Deformation Mapping service is performed exploiting either PSInSARTM or Conventional DInSAR (EarthView® InSAR). The processing approach is selected according to the availability of SAR data and users' requests.The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. Users are directly and actively involved in the validation of the Earth Observation products, by comparing them with ground data available at each site.In a first phase, the GlobVolcano Information System was designed, implemented and validated, involving a limited number of test areas and respective user organizations (Colima in Mexico, Merapi in Indonesia, Soufrière Hills in Montserrat Island, Piton de la Fournaise in La Reunion Island, Karthala in Comore Islands, Stromboli and Volcano in Italy). In particular Deformation Mapping results obtained for Piton de la Fournaise were compared with deformation rates measured by the volcano observatory using GPS stations and tiltmeters. IPGP (Institut de Physique du Globe de Paris) is responsible for the validation activities.The second phase of the project (currently on-going) concerns the service provision on pre-operational basis. Fifteen volcanic sites located in four continents are monitored and as many user organizations are involved and cooperating with the project team.In addition to the proprietary tools mentioned before, in

Soufriere Hills Volcano Resumes Activity

NASA Image and Video Library

2017-12-08

A massive eruption of Montserrat’s Soufrière Hills Volcano covered large portions of the island in debris. The eruption was triggered by a collapse of Soufrière Hills’ summit lava dome on February 11, 2010. Pyroclastic flows raced down the northern flank of the volcano, leveling trees and destroying buildings in the village of Harris, which was abandoned after Soufrière Hills became active in 1995. The Montserrat Volcano Observatory reported that some flows, about 15 meters (49 feet) thick, reached the sea at Trant’s Bay. These flows extended the island’s coastline up to 650 meters (2,100 feet). These false-color satellite images show the southern half of Montserrat before and after the dome collapse. The top image shows Montserrat on February 21, 2010, just 10 days after the event. For comparison, the bottom image shows the same area on March 17, 2007. Red areas are vegetated, clouds are white, blue/black areas are ocean water, and gray areas are covered by flow deposits. Fresh deposits tend to be lighter than older deposits. On February 21, the drainages leading down from Soufrière Hills, including the White River Valley, the Tar River Valley, and the Belham River Valley, were filled with fresh debris. According to the Montserrat Volcano Observatory, pyroclastic flows reached the sea through Aymers Ghaut on January 18, 2010, and flows entered the sea near Plymouth on February 5, 2010. NASA Earth Observatory image by Robert Simmon, using data from the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Robert Simmon. To read more go to: earthobservatory.nasa.gov/IOTD/view.php?id=42792 NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Cl/B ratio of geothermal fluid around Slamet Volcano, Jawa Tengah, Indonesia

NASA Astrophysics Data System (ADS)

Harijoko, Agung; Juhri, Saefudin

2017-12-01

Geothermal manifestations occurred in four areas surrounding Slamet Volcano, such as Guci, Baturraden, Paguyangan, and Bantarkawung. These areas are located of about 7.5 km, 8 km, 25 km and 33 km from the summit of Slamet volcano, respectively. We analyzed the chemical composition of cold and hot hater in order to understand the genesis and hydrological the relationship of the hot springs. The plot on HCO3-Cl-SO4 ternary diagram classified the hot water into four water types i.e. chloride-bicarbonate water (Bantarkawung), chloride water (Paguyangan), sulfate-chloride water (Baturraden), and bicarbonate water (Guci). The Cl/B ratio values indicate that the southern part of the Slamet volcano (Baturaden) hot springs have high Cl/B ratio compared to that of the northern hot springs (Guci area). While the hot springs in the western part (Paguyangan and Bantarkawung) are classified into high and low Cl/B ratio. This indicates that the hot springs in Paguyangan and Bantarkawung are the outflow of Baturraden and Guci.

Progressive glacial retreat in the Southern Altiplano (Uturuncu volcano, 22°S) between 65 and 14 ka constrained by cosmogenic 3He dating

NASA Astrophysics Data System (ADS)

Blard, Pierre-Henri; Lave, Jérôme; Farley, Kenneth A.; Ramirez, Victor; Jimenez, Nestor; Martin, Léo C. P.; Charreau, Julien; Tibari, Bouchaïb; Fornari, Michel

2014-07-01

This work presents the first reconstruction of late Pleistocene glacier fluctuations on Uturuncu volcano, in the Southern Tropical Andes. Cosmogenic 3He dating of glacial landforms provides constraints on ancient glacier position between 65 and 14 ka. Despite important scatter in the exposure ages on the oldest moraines, probably resulting from pre-exposure, these 3He data constrain the timing of the moraine deposits and subsequent glacier recessions: the Uturuncu glacier may have reached its maximum extent much before the global LGM, maybe as early as 65 ka, with an equilibrium line altitude (ELA) at 5280 m. Then, the glacier remained close to its maximum position, with a main stillstand identified around 40 ka, and another one between 35 and 17 ka, followed by a limited recession at 17 ka. Then, another glacial stillstand is identified upstream during the late glacial period, probably between 16 and 14 ka, with an ELA standing at 5350 m. This stillstand is synchronous with the paleolake Tauca highstand. This result indicates that this regionally wet and cold episode, during the Heinrich 1 event, also impacted the Southern Altiplano. The ELA rose above 5450 m after 14 ka, synchronously with the Bolling-Allerod.

Spreading volcanoes

USGS Publications Warehouse

Borgia, A.; Delaney, P.T.; Denlinger, R.P.

2000-01-01

As volcanoes grow, they become ever heavier. Unlike mountains exhumed by erosion of rocks that generally were lithified at depth, volcanoes typically are built of poorly consolidated rocks that may be further weakened by hydrothermal alteration. The substrates upon which volcanoes rest, moreover, are often sediments lithified by no more than the weight of the volcanic overburden. It is not surprising, therefore, that volcanic deformation includes-and in the long term is often dominated by-spreading motions that translate subsidence near volcanic summits to outward horizontal displacements around the flanks and peripheries. We review examples of volcanic spreading and go on to derive approximate expressions for the time volcanoes require to deform by spreading on weak substrates. We also demonstrate that shear stresses that drive low-angle thrust faulting from beneath volcanic constructs have maxima at volcanic peripheries, just where such faults are seen to emerge. Finally, we establish a theoretical basis for experimentally derived scalings that delineate volcanoes that spread from those that do not.

The Alaska Volcano Observatory - Expanded Monitoring of Volcanoes Yields Results

USGS Publications Warehouse

Brantley, Steven R.; McGimsey, Robert G.; Neal, Christina A.

2004-01-01

Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano Observatory (AVO) has installed new monitoring networks and used satellite data to track activity at Alaska's volcanoes, providing timely warnings and monitoring of frequent eruptions to the aviation industry and the general public. To minimize impacts from future eruptions, scientists at AVO continue to assess volcano hazards and to expand monitoring networks.

Mercury and Iodine systematics of volcanic arc fluids

NASA Astrophysics Data System (ADS)

Varekamp, J. C.; Kading, T.; Fehn, U.; Lu, Z.

2008-12-01

The mantle has low Mercury and Iodine concentrations, but these elements occur in volcanic gases and hydrothermal fluids at ppb (Hg) and ppm (Iodine) levels. Possibly, the Hg and Iodine concentrations in volcanic fluids reflect subducted sediment sources in arc magmas. Iodine is a biophilic element, and I129/I values indicate that subducted sediment (especially organic matter) is an important Iodine source for arc magmas. It is uncertain if this is true for Hg as well, although in the surface environment Hg is commonly associated with organic matter. We present 60 new analyses of Hg and I in fluids from volcanoes in Central America, New Zealand, Japan, and the Cascades. A first assessment suggests that Iodine is released to some degree in the early stage of subduction in the forearc, whereas Hg may be released largely below the main volcanic arc. Isotope and trace element signatures of volcanic rocks of the investigated volcanoes show no simple correlation with Hg or Iodine abundances. The acid hot spring fluids of Copahue volcano (Argentina) carried ~ 200 ppt Hg in January 1999, ~80 ppt Hg in March 2008, and 90 ppt Hg in the crater lake in March 1997. The dissolved Hg fluxes from the Copahue hydrothermal system are ~300 gr Hg/year in 1999 and ~130 gr Hg/year in 2008. The bulk hydrothermal Hg flux (particle bound+dissolved) in 2008 was ~ 350 gr Hg/year. The potential Mercury evasion from these hydrothermal spring fluids into the air has not yet been incorporated in these estimates.

Digital Geologic Map Database of Medicine Lake Volcano, Northern California

NASA Astrophysics Data System (ADS)

Ramsey, D. W.; Donnelly-Nolan, J. M.; Felger, T. J.

2010-12-01

Medicine Lake volcano, located in the southern Cascades ~55 km east-northeast of Mount Shasta, is a large rear-arc, shield-shaped volcano with an eruptive history spanning nearly 500 k.y. Geologic mapping of Medicine Lake volcano has been digitally compiled as a spatial database in ArcGIS. Within the database, coverage feature classes have been created representing geologic lines (contacts, faults, lava tubes, etc.), geologic unit polygons, and volcanic vent location points. The database can be queried to determine the spatial distributions of different rock types, geologic units, and other geologic and geomorphic features. These data, in turn, can be used to better understand the evolution, growth, and potential hazards of this large, rear-arc Cascades volcano. Queries of the database reveal that the total area covered by lavas of Medicine Lake volcano, which range in composition from basalt through rhyolite, is about 2,200 km2, encompassing all or parts of 27 U.S. Geological Survey 1:24,000-scale topographic quadrangles. The maximum extent of these lavas is about 80 km north-south by 45 km east-west. Occupying the center of Medicine Lake volcano is a 7 km by 12 km summit caldera in which nestles its namesake, Medicine Lake. The flanks of the volcano, which are dotted with cinder cones, slope gently upward to the caldera rim, which reaches an elevation of nearly 2,440 m. Approximately 250 geologic units have been mapped, only half a dozen of which are thin surficial units such as alluvium. These volcanic units mostly represent eruptive events, each commonly including a vent (dome, cinder cone, spatter cone, etc.) and its associated lava flow. Some cinder cones have not been matched to lava flows, as the corresponding flows are probably buried, and some flows cannot be correlated with vents. The largest individual units on the map are all basaltic in composition, including the late Pleistocene basalt of Yellowjacket Butte (296 km2 exposed), the largest unit on the

An Admittance Survey of Large Volcanoes on Venus: Implications for Volcano Growth

NASA Technical Reports Server (NTRS)

Brian, A. W.; Smrekar, S. E.; Stofan, E. R.

2004-01-01

Estimates of the thickness of the venusian crust and elastic lithosphere are important in determining the rheological and thermal properties of Venus. These estimates offer insights into what conditions are needed for certain features, such as large volcanoes and coronae, to form. Lithospheric properties for much of the large volcano population on Venus are not well known. Previous studies of elastic thickness (Te) have concentrated on individual or small groups of edifices, or have used volcano models and fixed values of Te to match with observations of volcano morphologies. In addition, previous studies use different methods to estimate lithospheric parameters meaning it is difficult to compare their results. Following recent global studies of the admittance signatures exhibited by the venusian corona population, we performed a similar survey into large volcanoes in an effort to determine the range of lithospheric parameters shown by these features. This survey of the entire large volcano population used the same method throughout so that all estimates could be directly compared. By analysing a large number of edifices and comparing our results to observations of their morphology and models of volcano formation, we can help determine the controlling parameters that govern volcano growth on Venus.

Volcanoes: Nature's Caldrons Challenge Geochemists.

ERIC Educational Resources Information Center

Zurer, Pamela S.

1984-01-01

Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

Syrian Volcano

NASA Image and Video Library

2006-07-23

This MOC image shows a small volcano in the Syria Planum region of Mars. Today, the lava flows that compose this small volcano are nearly hidden by a mantle of rough-textured, perhaps somewhat cemented, dust

Antarctic volcanoes: A remote but significant hazard

NASA Astrophysics Data System (ADS)

Geyer, Adelina; Martí, Alex; Folch, Arnau; Giralt, Santiago

2017-04-01

Ash emitted during explosive volcanic eruptions can be dispersed over massive areas of the globe, posing a threat to both human health and infrastructures, such as the air traffic. Some of the last eruptions occurred during this decade (e.g. 14/04/2010 - Eyjafjallajökull, Iceland; 24/05/2011-Grímsvötn, Iceland; 05/06/2011-Puyehue-Cordón Caulle, Chile) have strongly affected the air traffic in different areas of the world, leading to economic losses of billions of euros. From the tens of volcanoes located in Antarctica, at least nine are known to be active and five of them have reported volcanic activity in historical times. However, until now, no attention has been paid to the possible social, economical and environmental consequences of an eruption that would occur on high southern latitudes, perhaps because it is considered that its impacts would be minor or local, and mainly restricted to the practically inhabited Antarctic continent. We show here, as a case study and using climate models, how volcanic ash emitted during a regular eruption of one of the most active volcanoes in Antarctica, Deception Island (South Shetland Islands), could reach the African continent as well as Australia and South America. The volcanic cloud could strongly affect the air traffic not only in the region and at high southern latitudes, but also the flights connecting Africa, South America and Oceania. Results obtained are crucial to understand the patterns of volcanic ash distribution at high southern latitudes with obvious implications for tephrostratigraphical and chronological studies that provide valuable isochrones with which to synchronize palaeoclimate records. This research was partially funded by the MINECO grants VOLCLIMA (CGL2015-72629-EXP)and POSVOLDEC(CTM2016-79617-P)(AEI/FEDER, UE), the Ramón y Cajal research program (RYC-2012-11024) and the NEMOH European project (REA grant 34 agreement n° 289976).

Iceland Volcano

Atmospheric Science Data Center

2013-04-23

article title:  Eyjafjallajökull, Iceland, Volcano Ash Cloud     View larger ... Europe and captured this image of the Eyjafjallajökull Volcano ash cloud as it continued to drift over the continent. Unlike other ...

The Southern Part of the Southern Volcanic Zone (SSVZ; 42-46S) of the Andes: History of Medium and Large Explosive Holocene Eruptions

NASA Astrophysics Data System (ADS)

Stern, C. R.; Naranjo, J. A.

2008-12-01

Chaitén volcano is one of 13 large volcanic centers, and numerous small cones, comprising the southern part of the Andean Southern Volcanic Zone (SVZ), that results from the subduction of the Nazca plate (at 7.8 cm/yr) between the landward extension of the Chiloé FZ at 42S and the Chile Rise - Trench triple junction at 46S. Chaitén is a rhyolite dome inside a 3 km diameter caldera located 15 km west of the larger Michinmahuida stratovolcano. Other stratovolcanoes in the SSVZ include Yate, Hornopirén, Corcovado, Yanteles, Melimoyu, Mentolat, Cay and Macá. Hudson volcano, the southernmost in the Southern SVZ, is a large 10 km caldera, while Huequi and Hualaihué - Cordón Cabrera are a group of small aligned cinder cones possibly related to a larger eroded volcanic complex. Prior to the May 2008 eruption of Chaitén, the only well documented historic eruptions in this segment of the Andean arc were the explosive eruption of Hudson in August 1991 (Naranjo et al. 1993), and two eruptions of Michinmahuida in 1742 and 1834-35. Tephra deposits provide evidence of 11 prehistoric explosive Holocene eruptions of the southernmost SSVZ Hudson volcano, including two large eruptions near <6700 and <3600 BP (Naranjo and Stern 1998). The 6700 BP eruption produced greater than 18 km3 of andesitic tephra, possibly the largest Holocene eruption in all the southern Andes. Although Hudson is clearly the most active of the Southern SVZ volcanoes in terms of both volume and frequency of explosive eruptions, tephra deposits indicate that seven of the other SSVZ volcanoes, including Chaitén, also have had medium to large Holocene explosive eruptions (Naranjo and Stern 2004). Three of these eruptions were from Corcovado at approximately <9190, <7980 and <6870 BP, one from Yanteles at <9180 BP, two from Melimoyu at <2740 and <1750 BP, one from Mentolat at <6960 and one from Macá at <1540 BP. Two other eruptions, at <6350 and <3820 BP, we interpret as having been produced by

Dante's Volcano

NASA Technical Reports Server (NTRS)

1994-01-01

This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

Small Tharsis Volcano

NASA Technical Reports Server (NTRS)

2004-01-01

30 August 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small volcano located southwest of the giant volcano, Pavonis Mons, near 2.5oS, 109.4oW. Lava flows can be seen to have emanated from the summit region, which today is an irregularly-shaped collapse pit, or caldera. A blanket of dust mantles this volcano. Dust covers most martian volcanoes, none of which are young or active today. This picture covers an area about 3 km (1.9 mi) across; sunlight illuminates the scene from the left.

USGS GNSS Applications to Volcano Disaster Response and Hazard Mitigation

NASA Astrophysics Data System (ADS)

Lisowski, M.; McCaffrey, R.

2015-12-01

Volcanic unrest is often identified by increased rates of seismicity, deformation, or the release of volcanic gases. Deformation results when ascending magma accumulates in crustal reservoirs, creates new pathways to the surface, or drains from magma reservoirs to feed an eruption. This volcanic deformation is overprinted by deformation from tectonic processes. GNSS monitoring of volcanoes captures transient volcanic deformation and steady and transient tectonic deformation, and we use the TDEFNODE software to unravel these effects. We apply the technique on portions of the Cascades Volcanic arc in central Oregon and in southern Washington that include a deforming volcano. In central Oregon, the regional TDEFNODE model consists of several blocks that rotate and deform internally and a decaying inflationary volcanic pressure source to reproduce the crustal bulge centered ~5 km west of South Sister. We jointly invert 47 interferograms that cover the interval from 1992 to 2010, as well as 2001 to 2015 continuous GNSS (cGNSS) and survey-mode (sGNSS) time series from stations in and around the Three Sisters, Newberry, and Crater Lake areas. A single, smoothly-decaying ~5 km deep spherical or prolate spheroid volcanic pressure source activated around 1998 provides the best fit to the combined geodetic data. In southern Washington, GNSS displacement time-series track decaying deflation of a ~8 km deep magma reservoir that fed the 2004 to 2008 eruption of Mount St. Helens. That deformation reversed when it began to recharge after the eruption ended. Offsets from slow slip events on the Cascadia subduction zone punctuate the GNSS displacement time series, and we remove them by estimating source parameters for these events. This regional TDEFNODE model extends from Mount Rainier south to Mount Hood, and additional volcanic sources could be added if these volcanoes start deforming. Other TDEFNODE regional models are planned for northern Washington (Mount Baker and Glacier

Volcanoes: observations and impact

USGS Publications Warehouse

Thurber, Clifford; Prejean, Stephanie G.

2012-01-01

Volcanoes are critical geologic hazards that challenge our ability to make long-term forecasts of their eruptive behaviors. They also have direct and indirect impacts on human lives and society. As is the case with many geologic phenomena, the time scales over which volcanoes evolve greatly exceed that of a human lifetime. On the other hand, the time scale over which a volcano can move from inactivity to eruption can be rather short: months, weeks, days, and even hours. Thus, scientific study and monitoring of volcanoes is essential to mitigate risk. There are thousands of volcanoes on Earth, and it is impractical to study and implement ground-based monitoring at them all. Fortunately, there are other effective means for volcano monitoring, including increasing capabilities for satellite-based technologies.

Remote Triggering of Microearthquakes in the Piton de la Fournaise and Changbaishan Volcanoes

NASA Astrophysics Data System (ADS)

Li, C.; Liu, G.; Peng, Z.; Brenguier, F.; Dufek, J.

2015-12-01

Large earthquakes are capable of triggering seismic, aseismic and hydrological responses at long-range distances. In particular, recent studies have shown that microearthquakes are mostly triggered in volcanic/geothermal regions. However, it is still not clear how widespread the phenomenon is, and whether there are any causal links between large earthquakes and subsequent volcanic unrest/eruptions. In this study we conduct a systematic search for remotely triggered activity at the Piton de la Fournaise (PdlF) and Changbaishan (CBS) volcanoes. The PdlF is a shield volcano located on the east-southern part of the Reunion Island in Indian Ocean. It is one of the most active volcanoes around the world. The CBS volcano is an intraplate stratovolcano on the border between China and North Korea, and it was active with a major eruption around 1100 years ago and has been since dormant from AD 1903, however, it showed signals of unrest recently. We choose these regions because they are well instrumented and spatially close to recent large earthquakes, such as the 2004/12/26 Mw9.1 Sumatra, 2011/03/11 Mw9.0 Tohoku, and the 2012/04/11 Mw8.6 Indian Ocean Earthquakes. By examining continuous waveforms a few hours before and after many earthquakes since 2000, we find many cases of remote triggering around the CBS volcano. In comparison, we only identify a few cases of remotely triggered seismicity around the PdlF volcano, including the 2004 Sumatra earthquake. Notably, the 2012 Indian Ocean earthquake and its M8.2 aftershock did not trigger any clear increase of seismicity, at least during their surface waves. Our next step is to apply a waveform matching method to automatically detect volcano-seismicity in both regions, and then use them to better understand potential interactions between large earthquakes and volcanic activities.

Activity at Shiveluch Volcano

NASA Image and Video Library

2017-12-08

NASA image acquired Sept 7, 2010 Shiveluch (also spelled Sheveluch) is one of the largest and most active volcanoes on Russia’s Kamchatka Peninsula. It has been spewing ash and steam intermittently—with occasional dome collapses, pyroclastic flows, and lava flows, as well—for the past decade. Shiveluch is a stratovolcano, a steep-sloped formation of alternating layers of hardened lava, ash, and rocks thrown out by earlier eruptions. A lava dome has been growing southwest of the 3,283-meter (10,771-foot) summit. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite acquired this image on September 7, 2010. Brown and tan debris—perhaps ash falls, perhaps mud from lahars—covers the southern landscape of the volcano, while the hills on the northern side remain covered in snow and ice. The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that seismic activity at Shiveluch was "above background levels" from September 3-10. Ash plumes rose to an altitude of 6.5 kilometers (21,300 feet) on September 3-4, and gas-and-ash plumes were reported on September 7, when this image was acquired. According to the Smithsonian Institution's volcano program, at least 60 large eruptions of Shiveluch have occurred during the current Holocene Epoch of geological history. Intermittent explosive eruptions began in the 1990s, and the largest historical eruptions from Shiveluch occurred in 1854 and 1964. NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Mike Carlowicz. Instrument: EO-1 - ALI Credit: NASA Earth Observatory NASA Goddard Space Flight Center contributes to NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s endeavors by providing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on

A Scientific Excursion: Volcanoes.

ERIC Educational Resources Information Center

Olds, Henry, Jr.

1983-01-01

Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. VOLCANOES creates an excellent context for learning information about volcanoes and for developing skills and practicing methods needed to study behavior of volcanoes. (Author/JN)

Mud Volcanoes as Exploration Targets on Mars

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy Z.

2010-01-01

Tens of thousands of high-albedo mounds occur across the southern part of the Acidalia impact basin on Mars. These structures have geologic, physical, mineralogic, and morphologic characteristics consistent with an origin from a sedimentary process similar to terrestrial mud volcanism. The potential for mud volcanism in the Northern Plains of Mars has been recognized for some time, with candidate mud volcanoes reported from Utopia, Isidis, northern Borealis, Scandia, and the Chryse-Acidalia region. We have proposed that the profusion of mounds in Acidalia is a consequence of this basin's unique geologic setting as the depocenter for the tune fraction of sediments delivered by the outflow channels from the highlands.

Volcanic Hazards Associated with the NE Sector of Tacaná Volcano, Guatemala.

NASA Astrophysics Data System (ADS)

Hughes, S. R.; Saucedo, R.; Macias, J.; Arce, J.; Garcia-Palomo, A.; Mora, J.; Scolamacchia, T.

2003-12-01

Tacaná volcano, with a height of 4,030 m above sea level, straddles the southern Mexico/Guatemala border. Last active in 1986, when there was a small phreatic event with a duration of a few days, this volcano presents an impending hazard to over 250,000 people. The NE sector of the volcano reveals the violent volcanic history of Tacaná that may be indicative of a serious potential risk to the area. Its earliest pyroclastic history appears to consist of fall, flow, and surge deposits, together with lavas, that have formed megablocks within a series of old debris avalanche deposits. This sector collapse event is overlain by a sequence of pumice fall and ash flow deposits, of which the youngest, less-altered pumice fall deposit shows a minimum thickness of > 4 m, with a dispersal axis trending toward the NE. A second debris avalanche deposit, separated from the above deposits by a paleosoil, is dominated by megablocks of lava and scoriaceous dome material. The current topography around the northeastern flank of the volcano is determined by a third, and most recent debris avalanche deposit, a thick (> 20 m) sequence of six block and ash flows dated at around 16,000 years BP, each separated by 1-10 cm thick ash cloud surge deposit, together with secondary lahar deposits. These are followed by a at least 4 lava flows that extend 2 km down the flank of the volcano. It appears that the most recent pyroclastic event at Tacaná is also recorded in this sector of the volcano: above the block and ash flows occurs a > 1 m thick ash flow unit that can be seen at least 5 km from the vent. Lastly, the Santa Maria Ash fall deposit, produced in 1902, has capped most of the deposits at Tacaná.

Characteristics and management of the 2006-2008 volcanic crisis at the Ubinas volcano (Peru)

NASA Astrophysics Data System (ADS)

Rivera, Marco; Thouret, Jean-Claude; Mariño, Jersy; Berolatti, Rossemary; Fuentes, José

2010-12-01

Ubinas volcano is located 75 km East of Arequipa and ca. 5000 people are living within 12 km from the summit. This composite cone is considered the most active volcano in southern Peru owing to its 24 low to moderate magnitude (VEI 1-3) eruptions in the past 500 years. The onset of the most recent eruptive episode occurred on 27 March 2006, following 8 months of heightened fumarolic activity. Vulcanian explosions occurred between 14 April 2006 and September 2007, at a time ejecting blocks up to 40 cm in diameter to distances of 2 km. Ash columns commonly rose to 3.5 km above the caldera rim and dispersed fine ash and aerosols to distances of 80 km between April 2006 and April 2007. Until April 2007, the total volume of ash was estimated at 0.004 km 3, suggesting that the volume of fresh magma was small. Ash fallout has affected residents, livestock, water supplies, and crop cultivation within an area of ca. 100 km 2 around the volcano. Continuous degassing and intermittent mild vulcanian explosions lasted until the end of 2008. Shortly after the initial explosions on mid April 2006 that spread ash fallout within 7 km of the volcano, an integrated Scientific Committee including three Peruvian institutes affiliated to the Regional Committee of Civil Defense for Moquegua, aided by members of the international cooperation, worked together to: i) elaborate and publish volcanic hazard maps; ii) inform and educate the population; and iii) advise regional authorities in regard to the management of the volcanic crisis and the preparation of contingency plans. Although the 2006-2008 volcanic crisis has been moderate, its management has been a difficult task even though less than 5000 people now live around the Ubinas volcano. However, the successful management has provided experience and skills to the scientific community. This volcanic crisis was not the first one that Peru has experienced but the 2006-2008 experience is the first long-lasting crisis that the Peruvian civil

Preliminary volcano-hazard assessment for Akutan Volcano east-central Aleutian Islands, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Power, John A.; Richter, Donlad H.; McGimsey, Robert G.

1998-01-01

Akutan Volcano is a 1100-meter-high stratovolcano on Akutan Island in the east-central Aleutian Islands of southwestern Alaska. The volcano is located about 1238 kilometers southwest of Anchorage and about 56 kilometers east of Dutch Harbor/Unalaska. Eruptive activity has occurred at least 27 times since historical observations were recorded beginning in the late 1700?s. Recent eruptions produced only small amounts of fine volcanic ash that fell primarily on the upper flanks of the volcano. Small amounts of ash fell on the Akutan Harbor area during eruptions in 1911, 1948, 1987, and 1989. Plumes of volcanic ash are the primary hazard associated with eruptions of Akutan Volcano and are a major hazard to all aircraft using the airfield at Dutch Harbor or approaching Akutan Island. Eruptions similar to historical Akutan eruptions should be anticipated in the future. Although unlikely, eruptions larger than those of historical time could generate significant amounts of volcanic ash, fallout, pyroclastic flows, and lahars that would be hazardous to life and property on all sectors of the volcano and other parts of the island, but especially in the major valleys that head on the volcano flanks. During a large eruption an ash cloud could be produced that may be hazardous to aircraft using the airfield at Cold Bay and the airspace downwind from the volcano. In the event of a large eruption, volcanic ash fallout could be relatively thick over parts of Akutan Island and volcanic bombs could strike areas more than 10 kilometers from the volcano.

Unearthing The Eruptive Personality Of El Salvador's Santa Ana (Ilamatepec) Volcano Though In-depth Stratigraphic Analysis Of Pre-1904 Deposits

NASA Astrophysics Data System (ADS)

Gallant, E.; Martinez-Hackert, B.

2011-12-01

The Santa Ana (Ilamatepec) volcano (2384 m) in densely populated El Salvador Central America presents serious volcanic hazard potential. The volcano is a prevalent part of every day life in El Salvador; the sugarcane and coffee belt of the country are to its Southern and Western flanks, recreational areas lies to its East, and second and third largest cities of El Salvador exist within its 25 km radius. Understanding the eruptive characteristics and history is imperative due to the volcano's relative size (the highest in the country) and it's explosive, composite nature. Historical records indicate at least 9 potential VEI 3 eruptions since 1521 AD. The volcano's relative inaccessibility and potential hazards do not promote a vast reservoir of research activity, as can be seen in the scarcity of published papers on topics prior to the 1904 eruption. This research represents the first steps towards creating a comprehensive stratigraphic record of the crater and characterizing its eruptive history, with an eventual goal of recreating the volcanic structure prior to its collapse. Samples of pre-1904 eruptive material were taken from the southern wall of an E-W oriented fluvial gully located within the SSW of the tertiary crater. These were analyzed using thin sections and optical microscopy, grain size distribution techniques, and scanning electron microscopy. The 15-layer sequence indicates an explosive history characterized by intense phreatomagmatic phases, plinian, sub-plinian and basaltic/andesitic composition strombolian activity. Another poster within the session will discuss an older sequence within the walls of the secondary crater. Further detailed studies will be required to gain a better understanding of the characteristics of Santa Ana Volcano.

Space Radar Image of Colima Volcano, Jalisco, Mexico

NASA Technical Reports Server (NTRS)

1994-01-01

This is an image of the Colima volcano in Jalisco, Mexico, a vigorously active volcano that erupted as recently as July 1994. The eruption partially destroyed a lava dome at the summit and deposited a new layer of ash on the volcano's southern slopes. Surrounding communities face a continuing threat of ash falls and volcanic mudflows from the volcano, which has been designated one of 15 high-risk volcanoes for scientific study during the next decade. This image was acquired by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 24th orbit on October 1, 1994. The image is centered at 19.4 degrees north latitude, 103.7 degrees west longitude. The area shown is approximately 35.7 kilometers by 37.5 kilometers (22 miles by 23 miles). This single-frequency, multi-polarized SIR-C image shows: red as L-band horizontally transmitted and received; green as L-band horizontally transmitted and vertically received; and blue as the ratio of the two channels. The summit area appears orange and the recent deposits fill the valleys along the south and southwest slopes. Observations from space are helping scientists understand the behavior of dangerous volcanoes and will be used to mitigate the effects of future eruptions on surrounding populations. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: the L-band (24 cm), the C-band (6 cm) and the X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature

Preliminary volcano-hazard assessment for Aniakchak Volcano, Alaska

USGS Publications Warehouse

Neal, Christina A.; McGimsey, Robert G.; Miller, Thomas P.; Riehle, James R.; Waythomas, Christopher F.

2000-01-01

Aniakchak is an active volcano located on the Alaska Peninsula 670 kilometers southwest of Anchorage. The volcano consists of a dramatic, 10-kilometer-diameter, 0.5 to 1.0-kilometer-deep caldera that formed during a catastrophic eruption 3,500 years ago. Since then, at least a dozen separate vents within the caldera have erupted, often explosively, to produce lava flows and widespread tephra (ash) deposits. The most recent eruption at Aniakchak occurred in 1931 and was one of the largest explosive eruptions in Alaska in the last 100 years. Although Aniakchak volcano presently shows no signs of unrest, explosive and nonexplosive eruptions will occur in the future. Awareness of the hazards posed by future eruptions is a key factor in minimizing impact.

Shaking up volcanoes

USGS Publications Warehouse

Prejean, Stephanie G.; Haney, Matthew M.

2014-01-01

Most volcanic eruptions that occur shortly after a large distant earthquake do so by random chance. A few compelling cases for earthquake-triggered eruptions exist, particularly within 200 km of the earthquake, but this phenomenon is rare in part because volcanoes must be poised to erupt in order to be triggered by an earthquake (1). Large earthquakes often perturb volcanoes in more subtle ways by triggering small earthquakes and changes in spring discharge and groundwater levels (1, 2). On page 80 of this issue, Brenguier et al. (3) provide fresh insight into the interaction of large earthquakes and volcanoes by documenting a temporary change in seismic velocity beneath volcanoes in Honshu, Japan, after the devastating Tohoku-Oki earthquake in 2011.

Mud volcanoes on Mars?

NASA Technical Reports Server (NTRS)

Komar, Paul D.

1991-01-01

The term mud volcano is applied to a variety of landforms having in common a formation by extrusion of mud from beneath the ground. Although mud is the principal solid material that issues from a mud volcano, there are many examples where clasts up to boulder size are found, sometimes thrown high into the air during an eruption. Other characteristics of mud volcanoes (on Earth) are discussed. The possible presence of mud volcanoes, which are common and widespread on Earth, on Mars is considered.

Preliminary volcano-hazard assessment for Augustine Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Waitt, Richard B.

1998-01-01

Augustine Volcano is a 1250-meter high stratovolcano in southwestern Cook Inlet about 280 kilometers southwest of Anchorage and within about 300 kilometers of more than half of the population of Alaska. Explosive eruptions have occurred six times since the early 1800s (1812, 1883, 1935, 1964-65, 1976, and 1986). The 1976 and 1986 eruptions began with an initial series of vent-clearing explosions and high vertical plumes of volcanic ash followed by pyroclastic flows, surges, and lahars on the volcano flanks. Unlike some prehistoric eruptions, a summit edifice collapse and debris avalanche did not occur in 1812, 1935, 1964-65, 1976, or 1986. However, early in the 1883 eruption, a portion of the volcano summit broke loose forming a debris avalanche that flowed to the sea. The avalanche initiated a small tsunami reported on the Kenai Peninsula at English Bay, 90 kilometers east of the volcano. Plumes of volcanic ash are a major hazard to jet aircraft using Anchorage International and other local airports. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Eruptions similar to the historical and prehistoric eruptions are likely in Augustine's future.

Mud Volcanoes - Analogs to Martian Cones and Domes (by the Thousands!)

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy

2010-01-01

Mud volcanoes are mounds formed by low temperature slurries of gas, liquid, sediments and rock that erupt to the surface from depths of meters to kilometers. They are common on Earth, with estimates of thousands onshore and tens of thousands offshore. Mud volcanoes occur in basins with rapidly-deposited accumulations of fine-grained sediments. Such settings are ideal for concentration and preservation of organic materials, and mud volcanoes typically occur in sedimentary basins that are rich in organic biosignatures. Domes and cones, cited as possible mud volcanoes by previous authors, are common on the northern plains of Mars. Our analysis of selected regions in southern Acidalia Planitia has revealed over 18,000 such features, and we estimate that more than 40,000 occur across the area. These domes and cones strongly resemble terrestrial mud volcanoes in size, shape, morphology, associated flow structures and geologic setting. Geologic and mineralogic arguments rule out alternative formation mechanisms involving lava, ice and impacts. We are studying terrestrial mud volcanoes from onshore and submarine locations. The largest concentration of onshore features is in Azerbaijan, near the western edge of the Caspian Sea. These features are typically hundreds of meters to several kilometers in diameter, and tens to hundreds of meters in height. Satellite images show spatial densities of 20 to 40 eruptive centers per 1000 square km. Many of the features remain active, and fresh mud flows as long as several kilometers are common. A large field of submarine mud volcanoes is located in the Gulf of Cadiz, off the Atlantic coasts of Morocco and Spain. High-resolution sonar bathymetry reveals numerous km-scale mud volcanoes, hundreds of meters in height. Seismic profiles demonstrate that the mud erupts from depths of several hundred meters. These submarine mud volcanoes are the closest morphologic analogs yet found to the features in Acidalia Planitia. We are also conducting

Global synthesis of volcano deformation: Results of the Volcano Deformation Task Force

NASA Astrophysics Data System (ADS)

Pritchard, M. E.; Jay, J.; Biggs, J.; Ebmeier, S. K.; Delgado, F.

2013-12-01

Ground deformation in volcanic regions is being observed more frequently -- the number of known deforming volcanoes has increased from 44 in 1997 to more than 210 in 2013 thanks in large part thanks to the availability of satellite InSAR observations. With the launch of new SAR satellites in the coming years devoted to global deformation monitoring, the number of well-studied episodes of volcano deformation will continue to increase. But evaluating the significance of the observed deformation is not always straightforward -- how often do deformation episodes lead to eruption? Are there certain characteristics of the deformation or the volcano that make the linkage between deformation and eruption more robust -- for example the duration or magnitude of the ground deformation and/or the composition and tectonic setting of the volcano? To answer these questions, a global database of volcano deformation events is needed. Recognizing the need for global information on volcano deformation and the opportunity to address it with InSAR and other techniques, we formed the Volcano Deformation Database Task force as part of Global Volcano Model. The three objectives of our organization are: 1) to compile deformation observations of all volcanoes globally into appropriate formats for WOVOdat and the Global Volcanism Program of the Smithsonian Institution. 2) document any relation between deformation events and eruptions for the Global assessment of volcanic hazard and risk report for 2015 (GAR15) for the UN. 3) to better link InSAR and other remote sensing observations to volcano observatories. We present the first results from our global study of the relation between deformation and eruptions, including case studies of particular eruptions. We compile a systematically-observed catalog of >500 volcanoes with observation windows up to 20 years. Of 90 volcanoes showing deformation, 40 erupted. The positive predictive value (PPV = 0.44) linking deformation and eruption on this

Recent unrest and magma movements at Eyjafjallajökull and Katla volcanoes, Iceland

NASA Astrophysics Data System (ADS)

Sturkell, Erik; Sigmundsson, Freysteinn; Einarsson, PáLl

2003-08-01

Katla and Eyjafjallajökull volcanoes are situated 25 km apart at the southern tip of the Eastern Volcanic Zone in Iceland. Both have been active in historic time (last 1100 years) and have a history of simultaneous activity. The much more active Katla volcano has erupted at least 20 times, and Eyjafjallajökull's two eruptions were contemporaneous with Katla eruptions. Following a quiet period of several decades, the seismicity beneath Eyjafjallajökull was high in 1994 and again in 1999. The activity culminated in July 1999 when a flash flood occurred from the Mýrdalsjökull ice cap covering Katla, associated with changes in seismicity, bursts of volcanic tremor, and the formation and deepening of ice cauldrons. We report here results of deformation observations of these events, both by GPS geodesy and tilt measurements. The 1999 increase in seismicity at Eyjafjallajökull was associated with significant inflation of the volcano. The deformation data are modeled by a point pressure source at 3.5 km depth beneath the flank of the volcano, about 4 km south of the summit crater. Maximum uplift of the model is 0.35 m. A similar model also explains deformation associated with the 1994 seismic crisis. The deformation field of the Katla volcano is more difficult to ascertain due to the extensive glacier coverage. Movements of points on nunataks on and near the caldera rim indicate inflation and magma movements at shallow level beneath the caldera in connection with the events of July 1999.

The 1793 eruption of San Martín Tuxtla volcano, Veracruz, Mexico

NASA Astrophysics Data System (ADS)

Espíndola, J. M.; Zamora-Camacho, A.; Godinez, M. L.; Schaaf, P.; Rodríguez, S. R.

2010-11-01

San Martín Tuxtla (N18.562°; W95.199°, 1659 masl) is a basaltic volcano located in southern Veracruz, a Mexican State bordering the Gulf of Mexico. It rises in a volcanic field strewn with monogenetic volcanic cones, maars and three other large volcanoes mostly dormant since the late Pliocene: Santa Marta, San Martín Pajapan and Cerro El Vigía. The latest eruptive event of San Martín occurred in 1793 and was described by Don José Mariano Moziño, a naturalist under the commission of the Viceroy of the then New Spain. In this work we present results of the study of this eruption based on historical accounts and field observations. We identified an ash deposit around the volcano related to the 1793 eruption, mapped its distribution and determined its granulometric, petrographic and geochemical characteristics. These studies suggest that the volcano began its activity with explosive phreatomagmatic explosions, which were followed by Strombolian activity; this period lasting from March to October 1793. The activity continued with an effusive phase that lasted probably 2 years. The eruption covered an area of about 480 km 2 with at least 1 cm of ash; the fines reaching distances greater than 300 km from the crater. A total mass of about 2.5 × 10 14 g was ejected and the volcanic columns probably reached altitudes of the order of 10 km during the most explosive phases. The lava emitted formed a coulee that descended the northern flank of the volcano and has an approximate volume of 2.0 × 10 7 m 3.

Volcano-tectonic implications of 3-D velocity structures derived from joint active and passive source tomography of the island of Hawaii

USGS Publications Warehouse

Park, J.; Morgan, J.K.; Zelt, C.A.; Okubo, P.G.

2009-01-01

We present a velocity model of the onshore and offshore regions around the southern part of the island of Hawaii, including southern Mauna Kea, southeastern Hualalai, and the active volcanoes of Mauna Loa, and Kilauea, and Loihi seamount. The velocity model was inverted from about 200,000 first-arrival traveltime picks of earthquakes and air gun shots recorded at the Hawaiian Volcano Observatory (HVO). Reconstructed volcanic structures of the island provide us with an improved understanding of the volcano-tectonic evolution of Hawaiian volcanoes and their interactions. The summits and upper rift zones of the active volcanoes are characterized by high-velocity materials, correlated with intrusive magma cumulates. These high-velocity materials often do not extend the full lengths of the rift zones, suggesting that rift zone intrusions may be spatially limited. Seismicity tends to be localized seaward of the most active intrusive bodies. Low-velocity materials beneath parts of the active rift zones of Kilauea and Mauna Loa suggest discontinuous rift zone intrusives, possibly due to the presence of a preexisting volcanic edifice, e.g., along Mauna Loa beneath Kilauea's southwest rift zone, or alternatively, removal of high-velocity materials by large-scale landsliding, e.g., along Mauna Loa's western flank. Both locations also show increased seismicity that may result from edifice interactions or reactivation of buried faults. New high-velocity regions are recognized and suggest the presence of buried, and in some cases, previously unknown rift zones, within the northwest flank of Mauna Loa, and the south flanks of Mauna Loa, Hualalai, and Mauna Kea. Copyright 2009 by the American Geophysical Union.

Preliminary volcano-hazard assessment for Mount Spurr Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Nye, Christopher J.

2001-01-01

Mount Spurr volcano is an ice- and snow-covered stratovolcano complex located in the north-central Cook Inlet region about 100 kilometers west of Anchorage, Alaska. Mount Spurr volcano consists of a breached stratovolcano, a lava dome at the summit of Mount Spurr, and Crater Peak vent, a small stratocone on the south flank of Mount Spurr volcano. Historical eruptions of Crater Peak occurred in 1953 and 1992. These eruptions were relatively small but explosive, and they dispersed volcanic ash over areas of interior, south-central, and southeastern Alaska. Individual ash clouds produced by the 1992 eruption drifted east, north, and south. Within a few days of the eruption, the south-moving ash cloud was detected over the North Atlantic. Pyroclastic flows that descended the south flank of Crater Peak during both historical eruptions initiated volcanic-debris flows or lahars that formed temporary debris dams across the Chakachatna River, the principal drainage south of Crater Peak. Prehistoric eruptions of Crater Peak and Mount Spurr generated clouds of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. A flank collapse on the southeast side of Mount Spurr generated a large debris avalanche that flowed about 20 kilometers beyond the volcano into the Chakachatna River valley. The debris-avalanche deposit probably formed a large, temporary debris dam across the Chakachatna River. The distribution and thickness of volcanic-ash deposits from Mount Spurr volcano in the Cook Inlet region indicate that volcanic-ash clouds from most prehistoric eruptions were as voluminous as those produced by the 1953 and 1992 eruptions. Clouds of volcanic ash emitted from the active vent, Crater Peak, would be a major hazard to all aircraft using Ted Stevens Anchorage International Airport and other local airports and, depending on wind direction, could drift a considerable distance beyond the volcano. Ash fall from future eruptions could disrupt many

Volcanic geology of Furnas Volcano, São Miguel, Azores

NASA Astrophysics Data System (ADS)

Guest, J. E.; Gaspar, J. L.; Cole, P. D.; Queiroz, G.; Duncan, A. M.; Wallenstein, N.; Ferreira, T.; Pacheco, J.-M.

1999-09-01

Furnas is the easternmost of the three active central volcanoes on the island of São Miguel in the Azores. Unlike the other two central volcanoes, Sete Cidades and Fogo, Furnas does not have a well-developed edifice, but consists of a steep-sided caldera complex 8×5 km across. It is built on the outer flanks of the Povoação/Nordeste lava complex that forms the eastern end of São Miguel. Constructive flanks to the volcano exist on the southern side where they form the coastal cliffs, and to the west. The caldera margins tend to reflect the regional/local tectonic pattern which has also controlled the distribution of vents within the caldera and areas of thermal springs. Activity at Furnas has been essentially explosive, erupting materials of trachytic composition. Products associated with the volcano include plinian and sub-plinian pumice deposits, ignimbrites and surge deposits, phreatomagmatic ashes, block and ash deposits and dome materials. Most of the activity has occurred from vents within the caldera, or on the caldera margin, although strombolian eruptions with aa flows of ankaramite and hawaiite have occurred outside the caldera. The eruptive history consists of at least two major caldera collapses, followed by caldera infilling. Based on 14C dates, it appears that the youngest major collapse occurred about 12,000-10,000 years BP. New 14C dates for a densely welded ignimbrite suggest that a potential caldera-forming eruption occurred at about 30,000 years BP. Recent eruptions (<5000 years old) were mainly characterised by alternating episodes of magmatic and phreatomagmatic activity of plinian and sub-plinian magnitude, forming deposits of interbedded ash and lapilli. An historical eruption is documented in 1630 AD; new evidence suggests that another occurred during the early occupation of the area at about 1440 AD.

Chronology, Eruption Duration, and Atmospheric Contribution of the Martian Volcano Apollinaris Patera

USGS Publications Warehouse

Robinson, M.S.; Mouginis-Mark, P. J.; Zimbelman, J.R.; Wu, S.S.C.; Ablin, K.K.; Howington-Kraus, A. E.

1993-01-01

Geologic mapping, thermal inertia measurements, and an analysis of the color (visual wavelengths) of the martian volcano Apollinaris Patera indicate the existence of two different surface materials, comprising an early, easily eroded edifice, and a more recent, competent fan on the southern flank. A chronology of six major events that is consistent with the present morphology of the volcano has been identified. We propose that large scale explosive activity occurred during the formation of the main edifice and that the distinctive fan on the southern flank appears to have been formed by lavas of low eruptive rate similar to those that form compound pahoehoe flow fields on Earth. A basal escarpment typically 500 m in relief and morphologically similar to the one surrounding Olympus Mons was produced between the formation of the main edifice and the fan, indicating multistage eruptions over a protracted period of time. Contact relations between the volcanic units and the adjacent chaotic material indicate that formation of the chaotic material occurred over an extended period of time and may be related to the volcanic activity that formed Apollinaris Patera. Stereophotogrammetric measurements permit the volume of the volcano to be estimated at 105 km3. From this volume measurement and an inferred eruption rate (1.5 ?? 10-2 km3 yr-1) we estimate the total eruption duration for the main edifice to be ???107 yrs. Plausible estimates of the exsolved volatile content of the parent magma imply that greater than 1015 kg of water vapor was released into the atmosphere as a consequence of this activity. This large amount of water vapor as well as other exsolved gases must have had a significant impact on local, and possibly global, climatic conditions. ?? 1993 Academic Press. All rights reserved.

Klyuchevskaya Volcano

NASA Technical Reports Server (NTRS)

2007-01-01

The Klyuchevskaya Volcano on Russia's Kamchatka Peninsula continued its ongoing activity by releasing another plume on May 24, 2007. The same day, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image, at 01:00 UTC. In this image, a hotspot marks the volcano's summit. Outlined in red, the hotspot indicates where MODIS detected unusually warm surface temperatures. Blowing southward from the summit is the plume, which casts its shadow on the clouds below. Near the summit, the plume appears gray, and it lightens toward the south. With an altitude of 4,835 meters (15,863 feet), Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) is both the highest and most active volcano on the Kamchatka Peninsula. As part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Klyuchevskaya is estimated to have experienced more than 100 flank eruptions in the past 3,000 years. Since its formation 6,000 years ago, the volcano has seen few periods of inactivity. NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. The Rapid Response Team provides daily images of this region.

Volcano hazards assessment for the Lassen region, northern California

USGS Publications Warehouse

Clynne, Michael A.; Robinson, Joel E.; Nathenson, Manuel; Muffler, L.J. Patrick

2012-01-01

The Lassen region of the southernmost Cascade Range is an active volcanic area. At least 70 eruptions have occurred in the past 100,000 years, including 3 in the past 1,000 years, most recently in 1915. The record of past eruptions and the present state of the underlying magmatic and hydrothermal systems make it clear that future eruptions within the Lassen Volcanic Center are very likely. Although the annual probability of an eruption is small, the consequences of some types of eruptions could be severe. Compared to those of a typical Cascade composite volcano, eruptive vents at Lassen Volcanic Center and the surrounding area are widely dispersed, extending in a zone about 50 km wide from the southern boundary of Lassen Volcanic National Park north to the Pit River. This report presents a discussion of volcanic and other geologic hazards in the Lassen area and delineates hazards zones for different types of volcanic activity. Owing to its presence in a national park with significant visitorship, its explosive behavior, and its proximity to regional infrastructure, the Lassen Volcanic Center has been designated a "high threat volcano" in the U.S. Geological Survey National Volcano Early Warning System assessment. Volcanic eruptions are typically preceded by seismic activity and ground deformation, and the Lassen area has a network of seismometers and Global Positioning System stations in place to monitor for early warning of volcanic activity.

Mutnovsky and Gorely Volcanoes, Kamchatka as Planetary Analogue Sites

NASA Astrophysics Data System (ADS)

Evdokimova, N.; Izbekov, P. E.; Krupskaya, V.; Muratov, A.

2016-12-01

Recent advances in Mars studies suggest that volcanic rocks, which dominated Martian surface in the past, have been exposed to alteration processes in a water-bearing environment during Noachian, before 3.7 Gy. Active volcanoes on Earth are natural laboratories, where volcanic processes and their associated products can be studied directly. This is particularly important for studying of alteration of juvenile volcanic products in aqueous environment because of the transient nature of some of the alteration products, as well as the environment itself. Terrestrial analogues help us to better understand processes on Mars; they are particularly useful as a test sites for preparation to future Mars missions. In this presentation we describe planetary analogue sites at Mutnovsky and Gorely Volcanoes in Kamchatka, which might be helpful for comparative studies and preparation to future Mars missions. Mutnovsky and Gorely Volcanoes are located 75 km south of Petropavlovsk-Kamchatsky, in the southern part of the Kamchatka Peninsula, Russia. The modern volcanic landscape in the area was shaped in Holocene (recent 10,000 years) through intermittent eruption of magmas ranging in composition from basalts to dacites and rhyodacites, with basaltic andesite lavas dominating in the modern relief. Two localities could be of a particular interest: (1) Mutnovsky NW thermal field featuring processes of active hydrothermal alteration of lavas of basaltic andesite and (2) dry lake at the bottom of Gorely caldera featuring products of mechanical disintegration of basaltic andesite lavas by eolian processes with short seasonal sedimentation in aqueous environment.

Volcano spacing and plate rigidity

USGS Publications Warehouse

ten Brink, Uri S.

1991-01-01

In-plane stresses, which accompany the flexural deformation of the lithosphere under the load of adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

Hawaii's volcanoes revealed

USGS Publications Warehouse

Eakins, Barry W.; Robinson, Joel E.; Kanamatsu, Toshiya; Naka, Jiro; Smith, John R.; Takahashi, Eiichi; Clague, David A.

2003-01-01

Hawaiian volcanoes typically evolve in four stages as volcanism waxes and wanes: (1) early alkalic, when volcanism originates on the deep sea floor; (2) shield, when roughly 95 percent of a volcano's volume is emplaced; (3) post-shield alkalic, when small-volume eruptions build scattered cones that thinly cap the shield-stage lavas; and (4) rejuvenated, when lavas of distinct chemistry erupt following a lengthy period of erosion and volcanic quiescence. During the early alkalic and shield stages, two or more elongate rift zones may develop as flanks of the volcano separate. Mantle-derived magma rises through a vertical conduit and is temporarily stored in a shallow summit reservoir from which magma may erupt within the summit region or be injected laterally into the rift zones. The ongoing activity at Kilauea's Pu?u ?O?o cone that began in January 1983 is one such rift-zone eruption. The rift zones commonly extend deep underwater, producing submarine eruptions of bulbous pillow lava. Once a volcano has grown above sea level, subaerial eruptions produce lava flows of jagged, clinkery ?a?a or smooth, ropy pahoehoe. If the flows reach the ocean they are rapidly quenched by seawater and shatter, producing a steep blanket of unstable volcanic sediment that mantles the upper submarine slopes. Above sea level then, the volcanoes develop the classic shield profile of gentle lava-flow slopes, whereas below sea level slopes are substantially steeper. While the volcanoes grow rapidly during the shield stage, they may also collapse catastrophically, generating giant landslides and tsunami, or fail more gradually, forming slumps. Deformation and seismicity along Kilauea's south flank indicate that slumping is occurring there today. Loading of the underlying Pacific Plate by the growing volcanic edifices causes subsidence, forming deep basins at the base of the volcanoes. Once volcanism wanes and lava flows no longer reach the ocean, the volcano continues to submerge, while

Linking space observations to volcano observatories in Latin America: Results from the CEOS DRM Volcano Pilot

NASA Astrophysics Data System (ADS)

Delgado, F.; Pritchard, M. E.; Biggs, J.; Arnold, D. W. D.; Poland, M. P.; Ebmeier, S. K.; Wauthier, C.; Wnuk, K.; Parker, A. L.; Amelug, F.; Sansosti, E.; Mothes, P. A.; Macedo, O.; Lara, L.; Zoffoli, S.; Aguilar, V.

2015-12-01

Within Latin American, about 315 volcanoes that have been active in the Holocene, but according to the United Nations Global Assessment of Risk 2015 report (GAR15) 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) has developed a 3-year pilot project to demonstrate how satellite observations can be used to monitor large numbers of volcanoes cost-effectively, particularly in areas with scarce instrumentation and/or difficult access. The pilot aims to improve disaster risk management (DRM) by working directly with the volcano observatories that are governmentally responsible for volcano monitoring, and the project is possible thanks to data provided at no cost by international space agencies (ESA, CSA, ASI, DLR, JAXA, NASA, CNES). Here we highlight several examples of how satellite observations have been used by volcano observatories during the last 18 months to monitor volcanoes and respond to crises -- for example the 2013-2014 unrest episode at Cerro Negro/Chiles (Ecuador-Colombia border); the 2015 eruptions of Villarrica and Calbuco volcanoes, Chile; the 2013-present unrest and eruptions at Sabancaya and Ubinas volcanoes, Peru; the 2015 unrest at Guallatiri volcano, Chile; and the 2012-present rapid uplift at Cordon Caulle, Chile. Our primary tool is measurements of ground deformation made by Interferometric Synthetic Aperture Radar (InSAR) but thermal and outgassing data have been used in a few cases. InSAR data have helped to determine the alert level at these volcanoes, served as an independent check on ground sensors, guided the deployment of ground instruments, and aided situational awareness. We will describe several lessons learned about the type of data products and information that are most needed by the volcano observatories in different countries.

Reunion Island Volcano Erupts

NASA Technical Reports Server (NTRS)

2002-01-01

On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The volcano itself is located on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the volcano's flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active volcanoes, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Volcanic Ash Hazards and Risk in Argentina: Scientific and Social Collaborative Approaches.

NASA Astrophysics Data System (ADS)

Rovere, E. I., II; Violante, R. A.; Vazquez Herrera, M. D.; Martinez Fernandez, M. D. L. P.

2015-12-01

Due to the absence of alerts or volcanic impacts during 60 years (from 1932, Quizapu-Descabezado Grande -one of the major eruptions of the XX Century- until 1991 Hudson eruption) there was mild remembrance of volcanic hazards in the collective memory of the Argentina citizens. Since then and until April 2015, the social perception changed according to different factors: age, location, education, culture, vulnerability. This variability produces a maze of challenges that go beyond the scientific knowledge. Volcanic health hazards began to be understood in 2008 after the eruption of Chaiten volcano. The particle size of ashfall (<10 μ) and the silica composition were the main factors of concern on epidemiological monitoring. In 2011 the volcanic complex Puyehue - Cordon Caulle eruption produced ashfall through plumes that reached densely populated cities like San Carlos de Bariloche and Buenos Aires. Farther away in South Africa and New Zealand ash plumes forced airlines to cancel local and international flights for several weeks. The fear of another eruption did not wait long when Calbuco volcano started activity in April 2015, it came at a time when Villarrica volcano was also in an eruptive phase, and the SERNAGEOMIN Chile, through the Observatory OVDAS of the Southern Andes, faced multiple natural disasters at the same time, 3 volcanoes in activity, lahars, pyroclastic flows and floods in the North. In Argentina, critical infrastructure, farming, livestock and primary supplies were affected mainly in the western region. Copahue volcano, is increasing unstability on seismic and geochemistry data since 2012. Caviahue resort village, distant only 8 Km. from the active vent happens to be a high vulnerable location. In 2014 GEVAS (Geology, Volcanoes, Environment and Health) Network ARGENTINA Civil Association started collaborative activities with SEGEMAR and in 2015 with the IAPG (Geoethics, Argentina), intending to promote Best Practices in volcanic and geological

Tephrostratigraphy of Changbaishan volcano, northeast China, since the mid-Holocene

NASA Astrophysics Data System (ADS)

Sun, Chunqing; Liu, Jiaqi; You, Haitao; Nemeth, Karoly

2017-12-01

A detailed tephrostratigraphy of an active volcano is essential for evaluating its eruptive history, forecasting future eruptions and correlation with distal tephra records. Changbaishan volcano is known for its Millennium eruption (ME, AD 940s; VEI 7) and the ME tephra has been detected in Greenland ice cores ∼9000 km from the vent. However, the pre-Millennium (pre-ME) and post-Millennium (post-ME) eruptions are still poorly characterized. In this study, we present a detailed late Holocene eruptive sequence of Changbaishan volcano based on single glass shard compositions from tephra samples collected from around the caldera rim and flanks. Tephra ages are constrained by optically stimulated luminescence (OSL) and AMS 14C dates. Tephra from the mid-Holocene pre-ME eruption can be divided into two pyroclastic fall subunits, and it cannot be correlated with any known Changbaishan-sourced tephra recorded in the Japan Sea based on major element composition of glass shards, such as the B-J (Baegdusan-Japan Basin) and B-V (Baegdusan-Vladivostok-oki) tephras. ME pyroclastic fall deposits from the caldera rims and volcanic flanks can be correlated to the juvenile pumice lapilli or blocks within the pyroclastic density current (PDC) deposits deposited in the valleys around the volcano based on glass shard compositions. Our results indicate that the glass shard compositions of proximal ME tephra are more varied than previously thought and can be correlated with distal ME tephra. In addition, widely-dispersed mafic scoria was ejected by the ME Plinian column and deposited on the western and southern summits and the eastern flank of the volcano. Data for glass from post-ME eruptions, such as the historically-documented AD 1403, AD 1668 and AD 1702 eruptions, are reported here for the first time. Except for the ME, other Holocene eruptions, including pre-ME and post-ME eruptions, had the potential to form widely-distributed tephra layers around northeast Asia, and our dataset

The changing shapes of active volcanoes: History, evolution, and future challenges for volcano geodesy

USGS Publications Warehouse

Poland, Michael P.; Hamburger, Michael W.; Newman, Andrew V.

2006-01-01

At the very heart of volcanology lies the search for the 'plumbing systems' that form the inner workings of Earth’s active volcanoes. By their very nature, however, the magmatic reservoirs and conduits that underlie these active volcanic systems are elusive; mostly they are observable only through circumstantial evidence, using indirect, and often ambiguous, surficial measurements. Of course, we can infer much about these systems from geologic investigation of materials brought to the surface by eruptions and of the exposed roots of ancient volcanoes. But how can we study the magmatic processes that are occurring beneath Earth’s active volcanoes? What are the geometry, scale, physical, and chemical characteristics of magma reservoirs? Can we infer the dynamics of magma transport? Can we use this information to better forecast the future behavior of volcanoes? These questions comprise some of the most fundamental, recurring themes of modern research in volcanology. The field of volcano geodesy is uniquely situated to provide critical observational constraints on these problems. For the past decade, armed with a new array of technological innovations, equipped with powerful computers, and prepared with new analytical tools, volcano geodesists have been poised to make significant advances in our fundamental understanding of the behavior of active volcanic systems. The purpose of this volume is to highlight some of these recent advances, particularly in the collection and interpretation of geodetic data from actively deforming volcanoes. The 18 papers that follow report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide

The volcanic acidification of glacial Lake Caviahue, Province of Neuquen, Argentina

NASA Astrophysics Data System (ADS)

Varekamp, Johan C.

2008-12-01

Lake Caviahue (northern Patagonia, Argentina) is a large glacial lake acidified by volcanic fluids from Copahue volcano. The lake and the feeding rivers were sampled annually from 1997 till early 2006, including the eruptive period of 2000. Lake Caviahue waters evolved over time, with the most concentrated waters in 2000 during the eruptive period, followed by gradual dilution that was interrupted by renewed acidification in 2003-2004. Inversion of the lake water data and application of a dynamic non-steady state model for the lake provides our best quantitative estimates for the variation in element fluxes over the 9-year period. The model flux results agree well with most of the measured fluxes. The Copahue hydrothermal system had gently declining element fluxes between 1997 and mid-1999, although the lake was still becoming more concentrated. About 2-3 months before the 2000 eruption, element fluxes increased strongly, but the hydrothermal fluxes almost shutoff directly after the main eruptive events. The fluxes of several elements recovered post-2001, with an increase in element fluxes in 2003-2004; the lake became more dilute between 2004 and 2006. The intrusion of new magma into the hydrothermal system just prior to the 2000 eruption led to enhanced water rock interaction, with higher concentrations of the rock forming elements in the fluids, and the hot spring flow rate increased as a result of the higher pressure in the reservoir. The fluids became saturated in alunite and jarosite, and they were already saturated with anhydrite. Precipitation of these minerals possibly led to a decreased permeability of the hydrothermal reservoir, leading to the strongly reduced element fluxes just after the eruption. In addition, K, Al and S were retained in the newly precipitated minerals as well, further diminishing their export. The acidification in 2003-2004 may have resulted from a new small intrusion of magma or resulted from seismic activity that created new

Preliminary Volcano-Hazard Assessment for Gareloi Volcano, Gareloi Island, Alaska

USGS Publications Warehouse

Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

2008-01-01

Gareloi Volcano (178.794 degrees W and 51.790 degrees N) is located on Gareloi Island in the Delarof Islands group of the Aleutian Islands, about 2,000 kilometers west-southwest of Anchorage and about 150 kilometers west of Adak, the westernmost community in Alaska. This small (about 8x10 kilometer) volcano has been one of the most active in the Aleutians since its discovery by the Bering expedition in the 1740s, though because of its remote location, observations have been scant and many smaller eruptions may have gone unrecorded. Eruptions of Gareloi commonly produce ash clouds and lava flows. Scars on the flanks of the volcano and debris-avalanche deposits on the adjacent seafloor indicate that the volcano has produced large landslides in the past, possibly causing tsunamis. Such events are infrequent, occurring at most every few thousand years. The primary hazard from Gareloi is airborne clouds of ash that could affect aircraft. In this report, we summarize and describe the major volcanic hazards associated with Gareloi.

Nyamuragira Volcano Erupts

NASA Technical Reports Server (NTRS)

2002-01-01

Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 28, 2002. Nyamuragira is situated roughly in the center of this scene, roughly 100 km south of Lake Edward and just north of Lake Kivu (which is mostly obscured by the haze from the erupting volcano and the numerous fires burning in the surrounding countryside). Due south of Lake Kivu is the long, narrow Lake Tanganyika running south and off the bottom center of this scene.

Fluvial valleys on Martian volcanoes

NASA Technical Reports Server (NTRS)

Baker, Victor R.; Gulick, Virginia C.

1987-01-01

Channels and valleys were known on the Martian volcanoes since their discovery by the Mariner 9 mission. Their analysis has generally centered on interpretation of possible origins by fluvial, lava, or viscous flows. The possible fluvial dissection of Martian volcanoes has received scant attention in comparison to that afforded outflow, runoff, and fretted channels. Photointerpretative, mapping, and morphometric studies of three Martian volcanoes were initiated: Ceraunius Tholus, Hecate Tholus, and Alba Patera. Preliminary morphometric results indicate that, for these three volcanoes, valley junction angles increase with decreasing slope. Drainage densities are quite variable, apparently reflecting complex interactions in the landscape-forming factors described. Ages of the Martian volcanoes were recently reinterpreted. This refined dating provides a time sequence in which to evaluate the degradational forms. An anomaly has appeared from the initial study: fluvial valleys seem to be present on some Martian volcanoes, but not on others of the same age. Volcanic surfaces characterized only by high permeability lava flows may have persisted without fluvial dissection.

Seismic signature of a phreatic explosion: Hydrofracturing damage at Karthala volcano, Grande Comore Island, Indian Ocean

USGS Publications Warehouse

Savin, C.; Grasso, J.-R.; Bachelery, P.

2005-01-01

Karthala volcano is a basaltic shield volcano with an active hydrothermal system that forms the southern two-thirds of the Grande Comore Island, off the east coat of Africa, northwest of Madagascar. Since the start of volcano monitoring by the local volcano observatory in 1988, the July 11th, 1991 phreatic eruption was the first volcanic event seismically recorded on this volcano, and a rare example of a monitored basaltic shield. From 1991 to 1995 the VT locations, 0.5volcanoes, during the climax of the 1991 phreatic explosion, are due to the activation of the whole hydrothermal system, as roughly sized by the distribution of VT hypocenters. The seismicity rate in 1995 was still higher than the pre-eruption seismicity rate, and disagrees with the time pattern of thermo-elastic stress readjustment induced by single magma intrusions at basaltic volcanoes. We propose that it corresponds to the still ongoing relaxation of pressure heterogeneity within the hydrothermal system as suggested by the few LP events that still occurred in 1995. ?? Springer-Verlag 2005.

Numerical modeling of magma-tectonic interactions at Pacaya Volcano, Guatemala

NASA Astrophysics Data System (ADS)

Wauthier, C.

2017-12-01

Pacaya Volcano is composed of several volcanic cones located along the southern rim of the Amatitlan caldera, approximately 25 km south of Guatemala City. It is a basaltic volcano located in the Central American Volcanic Arc. The shallow magma plumbing system at Pacaya likely includes at least three magma reservoirs: a very shallow ( 0.2-0.4 km depth) reservoir located below and possibly within the MacKenney cone, a 4 km deep reservoir located northwest of the summit, and a shallow dike-like conduit below the summit which fed the recent flank eruptions. Pacaya's western flank is slipping in a stick-slip fashion, and the instability seems associated with larger volume eruptions. Flank instability phases indeed occurred in 2010 and 2014 in coincidence with major intrusive and eruptive phases, suggesting a positive feedback between the flank motion and major intrusions. Simple analytical models are insufficient to fit the geodetic observations and model the flank processes and their mechanical interactions with the magmatic system. Here, numerical modeling approaches are used to characterize the 2014 flank deformation episode and magma-tectonic interactions.

Potentially active volcanoes of Peru - Observations using Landsat Thematic Mapper and Space Shuttle imagery

NASA Technical Reports Server (NTRS)

De Silva, S. L.; Francis, P. W.

1990-01-01

A synoptic study of the volcanoes of southern Peru (14-17 deg S), the northernmost part of the Central Volcanic Zone (CVZ 14-28 deg S) of the Andes, was conducted on the basis of Landsat TM images and color photography. The volcanoes were classified and their relative ages determined using subtle glacial-morphological features. Eight of them were postulated as potentially active. These are located in a narrow volcanic zone which probably reflects a steep dip of the Nazca plate through the zone of magma generation. The break in the trend of the volcanic arc possibly reflects the complexity of the crustal stress field above a major segment boundary in the subducting plate. There are also fields of mafic monogenetic centers in this region. In comparison with the southern part of the CVZ, the general paucity of older volcanic edifices north of 17 deg S suggested a more recent onset of volcanism, a possible result of the oblique subduction of the Nazca ridge and the consequent northward migration of its intersection with the Peru-Chile trench. This, together with the lack of any large silicic caldera systems and youthful dacite domes, suggested that there are real differences in the volcanic evolution of the two parts of the CVZ.

Volcano monitoring with an infrared camera: first insights from Villarrica Volcano

NASA Astrophysics Data System (ADS)

Rosas Sotomayor, Florencia; Amigo Ramos, Alvaro; Velasquez Vargas, Gabriela; Medina, Roxana; Thomas, Helen; Prata, Fred; Geoffroy, Carolina

2015-04-01

This contribution focuses on the first trials of the, almost 24/7 monitoring of Villarrica volcano with an infrared camera. Results must be compared with other SO2 remote sensing instruments such as DOAS and UV-camera, for the ''day'' measurements. Infrared remote sensing of volcanic emissions is a fast and safe method to obtain gas abundances in volcanic plumes, in particular when the access to the vent is difficult, during volcanic crisis and at night time. In recent years, a ground-based infrared camera (Nicair) has been developed by Nicarnica Aviation, which quantifies SO2 and ash on volcanic plumes, based on the infrared radiance at specific wavelengths through the application of filters. Three Nicair1 (first model) have been acquired by the Geological Survey of Chile in order to study degassing of active volcanoes. Several trials with the instruments have been performed in northern Chilean volcanoes, and have proven that the intervals of retrieved SO2 concentration and fluxes are as expected. Measurements were also performed at Villarrica volcano, and a location to install a ''fixed'' camera, at 8km from the crater, was discovered here. It is a coffee house with electrical power, wifi network, polite and committed owners and a full view of the volcano summit. The first measurements are being made and processed in order to have full day and week of SO2 emissions, analyze data transfer and storage, improve the remote control of the instrument and notebook in case of breakdown, web-cam/GoPro support, and the goal of the project: which is to implement a fixed station to monitor and study the Villarrica volcano with a Nicair1 integrating and comparing these results with other remote sensing instruments. This works also looks upon the strengthen of bonds with the community by developing teaching material and giving talks to communicate volcanic hazards and other geoscience topics to the people who live "just around the corner" from one of the most active volcanoes

Erupting Volcano Mount Etna

NASA Technical Reports Server (NTRS)

2001-01-01

An Expedition Two crewmember aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

Causes, Dynamics and Impacts of Lahar Mass Flows due to the April 2015 Eruption of Calbuco Volcano, Chile

NASA Astrophysics Data System (ADS)

Dussaillant, Alejandro; Russell, Andy; Meier, Claudio; Rivera, Andres; Mella, Mauricio; Garrido, Natalia; Hernandez, Jorge; Napoleoni, Felipe; Gonzalez, Cristian

2016-04-01

Calbuco is a 2015m high, glacier capped, stratovolcano in the heavily populated Los Lagos region of southern Chile with a history of large volcanic eruptions in 1893-95, 1906-7, 1911-12, 1917, 1932, 1945, 1961 and 1972. Calbuco volcano experienced a powerful 90 minute eruption at 18:04h on 22 April, 2015 followed by additional major eruptions at 01:00h and 13:10h on 23 & 30 April, respectively, resulting in the evacuation of 6500 people and the imposition of a 20 km radius exclusion zone. Pyroclastic flows descended into several river catchments radiating from the volcano with lahars travelling distances of up to 14 km, reaching populated areas. We present findings from detailed field observations from April and July 2015, and January 2016, regarding the causes, dynamics and impacts of lahars generated by the April 2015 eruption, supported by satellite imagery, LiDAR and detailed rtkGPS & TLS surveys, as well as sediment sampling. Pyroclastic flows melted glacier ice and snow generating the largest lahars in the Rio Este and Rio Blanco Sur on the southern flanks of the volcano. Lahar deposits in the Rio Blanco Norte were buried by pyroclastic flow deposits with measured temperatures of up to 282°C three months after emplacement. Lahar erosional impacts included bedrock erosion, alluvial channel incision, erosion of surficial deposits and the felling of large areas of forest. Depositional landforms included boulder run-ups on the outsides of channel bends, boulder clusters and large woody debris jams. Lahars deposited up to 8m of sediment within distal reaches. Deposits on the southern flanks of Calbuco indicate the passage of multiple pulses of contrasting rheology. Lahar occurrence and magnitude was controlled by the pre-eruption distribution of snow and ice on the volcano. Pre-existing lahar channels controlled flows to lower piedmont zones where routing was determined by palaeo-lahar geomorphology. Ongoing erosion of proximal pyroclastic flow and lahar deposits

Earth's Volcanoes and their Eruptions; the 3rd edition of the Smithsonian Institution's Volcanoes of the World

NASA Astrophysics Data System (ADS)

Siebert, L.; Simkin, T.; Kimberly, P.

2010-12-01

The 3rd edition of the Smithsonian Institution’s Volcanoes of the World incorporates data on the world’s volcanoes and their eruptions compiled since 1968 by the Institution’s Global Volcanism Program (GVP). Published this Fall jointly by the Smithsonian and the University of California Press, it supplements data from the 1994 2nd edition and includes new data on the number of people living in proximity to volcanoes, the dominant rock lithologies at each volcano, Holocene caldera-forming eruptions, and preliminary lists of Pleistocene volcanoes and large-volume Pleistocene eruptions. The 3rd edition contains data on nearly 1550 volcanoes of known or possible Holocene age, including chronologies, characteristics, and magnitudes for >10,400 Holocene eruptions. The standard 20 eruptive characteristics of the IAVCEI volcano catalog series have been modified to include dated vertical edifice collapse events due to magma chamber evacuation following large-volume explosive eruptions or mafic lava effusion, and lateral sector collapse. Data from previous editions of Volcanoes of the World are also supplemented by listings of up to the 5 most dominant lithologies at each volcano, along with data on population living within 5, 10, 30, and 100 km radii of each volcano or volcanic field. Population data indicate that the most populated regions also contain the most frequently active volcanoes. Eruption data document lava and tephra volumes and Volcanic Explosivity Index (VEI) assignments for >7800 eruptions. Interpretation of VRF data has led to documentation of global eruption rates and the power law relationship between magnitude and frequency of volcanic eruptions. Data with volcanic hazards implications include those on fatalities and evacuations and the rate at which eruptions reach their climax. In recognition of the hazards implications of potential resumption of activity at pre-Holocene volcanoes, the 3rd edition includes very preliminary lists of Pleistocene

Organizational changes at Earthquakes & Volcanoes

USGS Publications Warehouse

Gordon, David W.

1992-01-01

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

Volcano monitoring at the U.S. Geological Survey's Hawaiian Volcano Observatory

USGS Publications Warehouse

Heliker, Christina C.; Griggs, J. D.; Takahashi, T. Jane; Wright, Thomas L.; Spall, Henry

1986-01-01

The island of Hawaii has one of the youngest landscapes on Earth, formed by frequent addition of new lava to its surface.  Because Hawaiian are generally nonexplosive and easily accessible, the island has long attracted geologists interested in studying the extraordinary power of volcanic eruptions.  The U.S. Geological Survey's Hawaiian Volcano Observatory (HVO), now nearing its 75th anniversary. has been in the forefront of volcanology since the 1900's.  This issue of Earthquakes and volcanoes is devoted to the work of the Observatory and its role in studying the most recent eruptions of Hawaii's two currently active volcanoes, Kilauea and Mauna Loa.

Volcano monitoring at the U.S. Geological Survey's Hawaiian Volcano Observatory

USGS Publications Warehouse

1986-01-01

The island of Hawaii has one of the youngest landscapes on Earth, formed by the frequent addition of new lava to its surface. Because Hawaiian eruptions are generally nonexplosive and easily accessible, the island has long attracted geologists interested in studying the extraordinary power of volcanic eruption. The U.S. Geological Survey's Hawaiian Volcano Observatory (HVO), now nearing its 75th anniversary, has been in the forefront of volcanology since the early 1900s. This issue of Earthquakes and Volcanoes is devoted to the work of the Observatory and its role in studying the most recent eruptions of Hawaii's two currently active volcanoes, Kilauea and Mauna Loa.

Morphological Analysis of Apo Volcanic Complex in Southern Mindanao, Philippines: implications on volcano-tectonic evolution of different volcanic units

NASA Astrophysics Data System (ADS)

Herrero, T. M. L.; van Wyk de Vries, B.; Lagmay, A. M. A.; Eco, R. C.

2015-12-01

The Apo Volcanic Complex (AVC) is one of the largest volcanic centers in the Philippines, located in the southern island of Mindanao. It is composed of four edifices and several smaller cones. The youngest volcanic unit, the Apo Dome, is the highest elevation in the Philippines. This unit is classified as potentially active, whereas other units, Talomo, Sibulan and Kitubod, are inactive. The study gives insight to the construction and deformation history of the volcanic units and imparts foresight to subsequent events that can affect populated areas. A morphological analysis integrating high-resolution digital terrain models and public domain satellite data and images was done to recognize and discriminate volcanic units and characterize volcano-tectonic features and processes. Morphological domains were defined based on surface textures, slope variation, degrees and controls of erosion, and lineament density and direction. This establishes the relative ages and extent of volcanic units as well as the volcano-tectonic evolution of the complex. Six edifice building events were recognized, two of which form the elevated base of Apo dome. The geodynamic setting of the region is imprinted in the volcanic units as five morphostructural lineaments. They reveal the changes in maximum regional stress through time such as the N-S extension found across the whole volcanic complex displaying the current stress regime. This has implications on the locality and propagation of geothermal activity, magma ascent, and edifice collapses. One main result of the compounded effects of inherited structures and current stress regime is the Sandawa Collapse Zone. This is a large valley formed by several collapses where NE-SW fractures propagate and the increasing lateral spreading by debuttressing continue to eat away the highest peak. The AVC is surrounded by the major metropolitan area of Davao City to the east and the cities of Kidapawan and Digos to the west and south, respectively

Volcanism, Iron, and Phytoplankton in the Heard and McDonald Islands Region, Southern Indian Ocean

NASA Astrophysics Data System (ADS)

Coffin, M. F.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Trull, T. W.; Heobi in2016 v01 Shipboard Party, T.

2016-12-01

Phytoplankton supply approximately half of the oxygen in Earth's atmosphere, and iron supply limits the growth of phytoplankton in the anemic Southern Ocean. Situated entirely within the Indian Ocean sector of the Southern Ocean are Australia's only active subaerial volcanoes, Heard and McDonald islands (HIMI) on the central Kerguelen Plateau, a large igneous province. Widespread fields of submarine volcanoes, some of which may be active, extend for distances of up to several hundred kilometers from the islands. The predominantly eastward-flowing Antarctic Circumpolar Current sweeps across the central Kerguelen Plateau, and extensive blooms of phytoplankton are observed on the Plateau down-current of HIMI. The goal of RV Investigator voyage IN2016_V01, conducted in January/February 2016, is to test the hypothesis that hydrothermal fluids, which cool active submarine volcanoes in the HIMI region, ascend from the seafloor and fertilise surface waters with iron, thereby enhancing biological productivity beginning with phytoplankton. Significant initial shipboard results include: Documentation, for the first time, of the role of active HIMI and nearby submarine volcanoes in supplying iron to the Southern Ocean. Nearshore waters had elevated dissolved iron levels. Although biomass was not correspondingly elevated, fluorescence induction data indicated highly productive resident phytoplankton. Discovery of >200 acoustic plumes emanating from the seafloor and ascending up to tens of meters into the water column near HIMI. Deep tow camera footage shows bubbles rising from the seafloor in an acoustic plume field north of Heard Island. Mapping 1,000 km2 of uncharted seafloor around HIMI. Submarine volcanic edifices punctuate the adjacent seafloor, and yielded iron-rich rocks similar to those found on HIMI, respectively. Acoustic plumes emanating from some of these features suggest active seafloor hydrothermal systems.

Colima Volcano, Mexico

NASA Image and Video Library

1995-10-29

STS073-E-5274 (3 Nov. 1995) --- Colima was photographed with a color Electronic Still Camera (ESC) onboard the Earth-orbiting space shuttle Columbia. The volcano lies due south of Guadalajara and Lake Chapala. It is considered to be one of Mexico's most active and most dangerous volcanoes, lying not far from heavily populated areas.

Nyamuragira Volcano Erupts

NASA Technical Reports Server (NTRS)

2002-01-01

Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This pair of images was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 26. The image on the left shows the scene in true color. The small purple box in the upper righthand corner marks the location of Nyamuragira's hot summit. The false-color image on the right shows the plume from the volcano streaming southwestward. This image was made using MODIS' channels sensitive at wavelengths from 8.5 to 11 microns. Red pixels indicate high concentrations of sulphur dioxide. Image courtesy Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison

The California Volcano Observatory: Monitoring the state's restless volcanoes

USGS Publications Warehouse

Stovall, Wendy K.; Marcaida, Mae; Mangan, Margaret T.

2014-01-01

Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 years—most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in the northern part of the State—and future volcanic eruptions are inevitable. The U.S. Geological Survey California Volcano Observatory monitors the State's potentially hazardous volcanoes.

Volcanoes. A planetary perspective.

NASA Astrophysics Data System (ADS)

Francis, P.

In this book, the author gives an account of the familiar violent aspects of volcanoes and the various forms that eruptions can take. He explores why volcanoes exist at all, why volcanoes occur where they do, and how examples of major historical eruptions can be interpreted in terms of physical processes. Throughout he attempts to place volcanism in a planetary perspective, exploring the pre-eminent role of submarine volcanism on Earth and the stunning range of volcanic phenomena revealed by spacecraft exploration of the solar system.

Volcano deformation and gravity workshop synopsis and outcomes: The 2008 volcano deformation and temporal gravity change workshop

USGS Publications Warehouse

Dzurisin, Daniel; Lu, Zhong

2009-01-01

A volcano workshop was held in Washington State, near the U.S. Geological Survey (USGS) Cascades Volcano Observatory. The workshop, hosted by the USGS Volcano Hazards Program (VHP), included more than 40 participants from the United States, the European Union, and Canada. Goals were to promote (1) collaboration among scientists working on active volcanoes and (2) development of new tools for studying volcano deformation. The workshop focused on conventional and emerging techniques, including the Global Positioning System (GPS), borehole strain, interferometric synthetic aperture radar (InSAR), gravity, and electromagnetic imaging, and on the roles of aqueous and magmatic fluids.

Vertical Motions of Oceanic Volcanoes

NASA Astrophysics Data System (ADS)

Clague, D. A.; Moore, J. G.

2006-12-01

Oceanic volcanoes offer abundant evidence of changes in their elevations through time. Their large-scale motions begin with a period of rapid subsidence lasting hundreds of thousands of years caused by isostatic compensation of the added mass of the volcano on the ocean lithosphere. The response is within thousands of years and lasts as long as the active volcano keeps adding mass on the ocean floor. Downward flexure caused by volcanic loading creates troughs around the growing volcanoes that eventually fill with sediment. Seismic surveys show that the overall depression of the old ocean floor beneath Hawaiian volcanoes such as Mauna Loa is about 10 km. This gross subsidence means that the drowned shorelines only record a small part of the total subsidence the islands experienced. In Hawaii, this history is recorded by long-term tide-gauge data, the depth in drill holes of subaerial lava flows and soil horizons, former shorelines presently located below sea level. Offshore Hawaii, a series of at least 7 drowned reefs and terraces record subsidence of about 1325 m during the last half million years. Older sequences of drowned reefs and terraces define the early rapid phase of subsidence of Maui, Molokai, Lanai, Oahu, Kauai, and Niihau. Volcanic islands, such as Maui, tip down toward the next younger volcano as it begins rapid growth and subsidence. Such tipping results in drowned reefs on Haleakala as deep as 2400 m where they are tipped towards Hawaii. Flat-topped volcanoes on submarine rift zones also record this tipping towards the next younger volcano. This early rapid subsidence phase is followed by a period of slow subsidence lasting for millions of years caused by thermal contraction of the aging ocean lithosphere beneath the volcano. The well-known evolution along the Hawaiian chain from high to low volcanic island, to coral island, and to guyot is due to this process. This history of rapid and then slow subsidence is interrupted by a period of minor uplift

Eruption of Kliuchevskoi volcano

NASA Image and Video Library

1994-10-04

STS068-273-060 (4 October 1994) --- Astronauts aboard the Space Shuttle Endeavour recorded this follow-up 70mm frame of the Kliuchevskoi volcano on the Kamchatka Peninsula in Russia. The volcano was near its peak on launch day, five days earlier, but only a small steam plume was rising from the summit in this Day 5 photo. Tendrils of ash are airborne on the northern flank of the volcano. Scientists feel that the source of these plumes is from a flow down the mountain's northern flank. The entire summit region is covered in ash. As various members of the six-person crew were using handheld cameras to record the various stages of the volcano, hardware in Endeavour's cargo bay was taking radar data of the event in support of the Space Radar Laboratory (SRL-2) mission.

The New USGS Volcano Hazards Program Web Site

NASA Astrophysics Data System (ADS)

Venezky, D. Y.; Graham, S. E.; Parker, T. J.; Snedigar, S. F.

2008-12-01

The U.S. Geological Survey's (USGS) Volcano Hazard Program (VHP) has launched a revised web site that uses a map-based interface to display hazards information for U.S. volcanoes. The web site is focused on better communication of hazards and background volcano information to our varied user groups by reorganizing content based on user needs and improving data display. The Home Page provides a synoptic view of the activity level of all volcanoes for which updates are written using a custom Google® Map. Updates are accessible by clicking on one of the map icons or clicking on the volcano of interest in the adjacent color-coded list of updates. The new navigation provides rapid access to volcanic activity information, background volcano information, images and publications, volcanic hazards, information about VHP, and the USGS volcano observatories. The Volcanic Activity section was tailored for emergency managers but provides information for all our user groups. It includes a Google® Map of the volcanoes we monitor, an Elevated Activity Page, a general status page, information about our Volcano Alert Levels and Aviation Color Codes, monitoring information, and links to monitoring data from VHP's volcano observatories: Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Long Valley Observatory (LVO), Hawaiian Volcano Observatory (HVO), and Yellowstone Volcano Observatory (YVO). The YVO web site was the first to move to the new navigation system and we are working on integrating the Long Valley Observatory web site next. We are excited to continue to implement new geospatial technologies to better display our hazards and supporting volcano information.

Mount Rainier active cascade volcano

NASA Technical Reports Server (NTRS)

1994-01-01

Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the volcano empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active volcano. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the volcano during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the volcano are poorly understood.

For Kids | Volcano World | Oregon State University

Science.gov Websites

Volcanic Gases Volcanic Lightning Volcanic Sounds Volcanic Hazards Kids Only! Art Gallery Volcano Games Lightning Volcanic Sounds Volcanic Hazards Kids Only! Art Gallery Volcano Games Adventures and Fun Virtual volcano? Check out our games and fun section below! Kids' Volcano Art Gallery Games & Fun Stuff

DTM-based automatic mapping and fractal clustering of putative mud volcanoes in Arabia Terra craters

NASA Astrophysics Data System (ADS)

Pozzobon, R. P.; Mazzarini, F. M.; Massironi, M. M.; Cremonese, G. C.; Rossi, A. P. R.; Pondrelli, M. P.; Marinangeli, L. M.

2017-09-01

Arabia Terra is a region of Mars where occurrence of past-water manifests at surface and subsurface. To date, several landforms associated with this activity were recognized and mapped, directly influencing the models of fluid circulation. In particular, within several craters such as Firsoff and an unnamed southern crater, putative mud volcanoes were described by several authors. In fact, numerous mounds (from 30 m of diameter in the case of monogenic cones, up to 3-400 m in the case of coalescing mounds) present an apical vent-like depression, resembling subaerial Azerbaijan mud volcanoes and gryphons. To this date, landform analysis through topographic position index and curvatures based on topography was never attempted. We hereby present a landform classification method suitable for mounds automatic mapping. Their resulting spatial distribution is then studied in terms of self-similar clustering.

The Quaternary calc-alkaline volcanism of the Patagonian Andes close to the Chile triple junction: geochemistry and petrogenesis of volcanic rocks from the Cay and Maca volcanoes (˜45°S, Chile)

NASA Astrophysics Data System (ADS)

D'Orazio, M.; Innocenti, F.; Manetti, P.; Tamponi, M.; Tonarini, S.; González-Ferrán, O.; Lahsen, A.; Omarini, R.

2003-08-01

Major- and trace-element, Sr-Nd isotopes, and mineral chemistry data were obtained for a collection of volcanic rock samples erupted by the Cay and Maca Quaternary volcanoes, Patagonian Andes (˜45°S, Chile). Cay and Maca are two large, adjacent stratovolcanoes that rise from the Chiloe block at the southern end of the southern volcanic zone (SVZ) of the Andes. Samples from the two volcanoes are typical medium-K, calc-alkaline rocks that form two roughly continuous, largely overlapping series from subalkaline basalt to dacite. The overall geochemistry of the samples studied is very similar to that observed for most volcanoes from the southern SVZ. The narrow range of Sr-Nd isotope compositions ( 87Sr/ 86Sr=0.70389-0.70431 and 143Nd/ 144Nd=0.51277-0.51284) and the major- and trace-element distributions indicate that the Cay and Maca magmas differentiated by crystal fractionation without significant contribution by crustal contamination. This is in accordance with the thin (<30 km), relatively young (Paleozoic or more recent) continental crust beneath the volcanoes. The nature of the subduction-derived materials involved in the genesis of the Cay and Maca magmas is investigated by means of the relative concentration of fluid mobile (e.g. Ba) and fluid immobile (e.g. Nb, Ta, Zr, Y) elements and other relevant trace-element ratios (e.g. Sr/Y). The results indicate that small amounts (<1 wt%) of both subducted sediments and slab-released fluids were added to the mantle sources of the Cay and Maca volcanoes and that, despite the very young age (<10 Ma) of the oceanic lithosphere subducted beneath the volcanoes, slab melts were not involved in the magma genesis. Notwithstanding the proximity of the Cay and Maca magma sources to the northern edge of the slab window generated by the subduction of the Chile ridge under the South American plate, we did not find any geochemical evidence for a contribution of a subslab asthenospheric mantle. However, this mantle has been used

GlobVolcano pre-operational services for global monitoring active volcanoes

NASA Astrophysics Data System (ADS)

Tampellini, Lucia; Ratti, Raffaella; Borgström, Sven; Seifert, Frank Martin; Peltier, Aline; Kaminski, Edouard; Bianchi, Marco; Branson, Wendy; Ferrucci, Fabrizio; Hirn, Barbara; van der Voet, Paul; van Geffen, J.

2010-05-01

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate users (e.g. Civil Protection) in their monitoring activities. The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. In a first phase, a complete information system has been designed, implemented and validated, involving a limited number of test areas and respective user organizations. In the currently on-going second phase, GlobVolcano is delivering pre-operational services over 15 volcanic sites located in three continents and as many user organizations are involved and cooperating with the project team. The set of GlobVolcano offered EO based information products is composed as follows: Deformation Mapping DInSAR (Differential Synthetic Aperture Radar Interferometry) has been used to study a wide range of surface displacements related to different phenomena (e.g. seismic faults, volcanoes, landslides) at a spatial resolution of less than 100 m and cm-level precision. Permanent Scatterers SAR Interferometry method (PSInSARTM) has been introduced by Politecnico of Milano as an advanced InSAR technique capable of measuring millimetre scale displacements of individual radar targets on the ground by using multi-temporal data-sets, estimating and removing the atmospheric components. Other techniques (e.g. CTM) have followed similar strategies and have shown promising results in different scenarios. Different processing approaches have been adopted, according to data availability, characteristic of the area and dynamic characteristics of the volcano. Conventional DInSAR: Colima (Mexico), Nyiragongo (Congo), Pico (Azores), Areanal (Costa Rica) PSInSARTM: Piton de la Fournaise (La Reunion Island

Volcano art at Hawai`i Volcanoes National Park—A science perspective

USGS Publications Warehouse

Gaddis, Ben; Kauahikaua, James P.

2018-03-26

Long before landscape photography became common, artists sketched and painted scenes of faraway places for the masses. Throughout the 19th century, scientific expeditions to Hawaiʻi routinely employed artists to depict images for the people back home who had funded the exploration and for those with an interest in the newly discovered lands. In Hawaiʻi, artists portrayed the broad variety of people, plant and animal life, and landscapes, but a feature of singular interest was the volcanoes. Painters of early Hawaiian volcano landscapes created art that formed a cohesive body of work known as the “Volcano School” (Forbes, 1992). Jules Tavernier, Charles Furneaux, and D. Howard Hitchcock were probably the best known artists of this school, and their paintings can be found in galleries around the world. Their dramatic paintings were recognized as fine art but were also strong advertisements for tourists to visit Hawaiʻi. Many of these masterpieces are preserved in the Museum and Archive Collection of Hawaiʻi Volcanoes National Park, and in this report we have taken the opportunity to match the artwork with the approximate date and volcanological context of the scene.

Eruption of Shiveluch Volcano, Kamchatka Peninsula

NASA Technical Reports Server (NTRS)

2007-01-01

On March 29, 2007, the Shiveluch Volcano on the Russian Federation's Kamchatka Peninsula erupted. According to the Alaska Volcano Observatory the volcano underwent an explosive eruption between 01:50 and 2:30 UTC, sending an ash cloud skyward roughly 9,750 meters (32,000 feet), based on visual estimates. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA's Aqua satellite took this picture at 02:00 UTC on March 29. The top image shows the volcano and its surroundings. The bottom image shows a close-up view of the volcano at 250 meters per pixel. Satellites often capture images of volcanic ash plumes, but usually as the plumes are blowing away. Plumes have been observed blowing away from Shiveluch before. This image, however, is different. At the time the Aqua satellite passed overhead, the eruption was recent enough (and the air was apparently still enough) that the ash cloud still hovered above the summit. In this image, the bulbous cloud casts its shadow northward over the icy landscape. Volcanic ash eruptions inject particles into Earth's atmosphere. Substantial eruptions of light-reflecting particles can reduce temperatures and even affect atmospheric circulation. Large eruptions impact climate patterns for years. A massive eruption of the Tambora Volcano in Indonesia in 1815, for instance, earned 1816 the nickname 'the year without a summer.' Shiveluch is a stratovolcano--a steep-sloped volcano composed of alternating layers of solidified ash, hardened lava, and volcanic rocks. One of Kamchatka's largest volcanoes, it sports a summit reaching 3,283 meters (10,771 feet). Shiveluch is also one of the peninsula's most active volcanoes, with an estimated 60 substantial eruptions in the past 10,000 years.

Structural evolution of deep-water submarine intraplate volcanoes / Azores

NASA Astrophysics Data System (ADS)

Stakemann, Josefine; Huebscher, Christian; Beier, Christoph; Hildenbrand, Anthony; Nomikou, Paraskevi; Terrinha, Pedro; Weiß, Benedikt

2017-04-01

We present multibeam and high-resolution reflection seismic data which elucidate the architecture of three submarine intraplate volcanoes located in the southern Azores Archipelago. Data have been collected during RV Meteor cruise M113 in 2015. Four GI-Guns served as the seismic source. The digital streamer comprised 144 channels distributed over a length of 600 m. The three cones are situated in a depth down to 2300 m with heights varying between 200 m and 243 m, an average diameter of 1360 m and an average slope angle of ca. 22°. All three circular cones are surrounded by a circular channel. These features, previously named "fried eggs" were previously interpreted as impact crater (Dias et al., 2009). A comparison with nearby submarine volcanoes close to São Miguel island (Weiß et al., 2015), however, strongly suggests a volcanic origin. The seismic data indicate that the volcanic cones formed on top of a ca. 100 m thick pelagic succession covering the igneous basement. Magma ascent deformed the volcanic basement, displaced the pelagic sediments and a first eruption phase formed a small, seismically transparent volcanic cone. Further eruptions created a volcanic cone with rather transparent reflections within the inferior region changing to strong reflection amplitudes with a chaotic pattern in the superior area. Compared to the igneous basement internal reflection amplitudes are mainly weak. The seismic transparency and slope angle exclude the presence of effusive rocks, since lavas usually create strong impedance contrasts. A comparison of the seismic characteristics with those from submarine Kolumbo volcano (Hübscher et al., 2015) suggests volcaniclastic lithologies from explosive eruptions. The circular channel around the volcanic cone shows the characteristics of a moat channel created by bottom currents. References: Dias, F.C., Lourenco, N., Lobo, A., Santos de Campos, A., Pinto de Abreu, M., 2009. "Fried Egg": An Oceanic Impact Crater in the Mid

Orographic Flow over an Active Volcano

NASA Astrophysics Data System (ADS)

Poulidis, Alexandros-Panagiotis; Renfrew, Ian; Matthews, Adrian

2014-05-01

Orographic flows over and around an isolated volcano are studied through a series of numerical model experiments. The volcano top has a heated surface, so can be thought of as "active" but not erupting. A series of simulations with different atmospheric conditions and using both idealised and realistic configurations of the Weather Research and Forecast (WRF) model have been carried out. The study is based on the Soufriere Hills volcano, located on the island of Montserrat in the Caribbean. This is a dome-building volcano, leading to a sharp increase in the surface skin temperature at the top of the volcano - up to tens of degrees higher than ambient values. The majority of the simulations use an idealised topography, in order for the results to have general applicability to similar-sized volcanoes located in the tropics. The model is initialised with idealised atmospheric soundings, representative of qualitatively different atmospheric conditions from the rainy season in the tropics. The simulations reveal significant changes to the orographic flow response, depending upon the size of the temperature anomaly and the atmospheric conditions. The flow regime and characteristic features such as gravity waves, orographic clouds and orographic rainfall patterns can all be qualitatively changed by the surface heating anomaly. Orographic rainfall over the volcano can be significantly enhanced with increased temperature anomaly. The implications for the eruptive behaviour of the volcano and resulting secondary volcanic hazards will also be discussed.

Geophysical surveys on permafrost in Coropuna and Chachani volcanoes (southern Peru)

NASA Astrophysics Data System (ADS)

Ubeda, Jose; Yoshikawa, Kenji; Pari, Walter; Palacios, David; Macias, Pablo; Apaza, Fredy; Ccallata, Beto; Miranda, Rafael; Concha, Ronald; Vasquez, Pool; Cruz, Rolando

2015-04-01

A network of air and ground temperature sensors installed 2004-2014 has enabled the discovery of permafrost on the Coropuna (6377 m) and Chachani (6057 m) volcanoes. However, on the Misti (5820 m) volcano there is no permafrost, which can be attributed to geothermal heat. Misti and Chachani are very close to each other, near the city of Arequipa (S. Peru). Coropuna is 150 km to the west. Various volcanic eruptions have taken place on Misti and Coropuna in the last 10 ka (Úbeda et al, 2012). The volcanic activity on the Chachani seems to be much older, although it has not been researched to date. Coropuna is covered by a glacial system of ~40 km2 (23-11-2013) and the moraines surrounding the volcanic complex indicate a surface of >500 km2 >10 ka ago (Úbeda et al, 2011). On Chachani the evidence also suggests a great extent in the past although in this case there are no glaciers conserved at the present day. On Misti there are currently no glaciers either, nor is there any evidence conserved of their earlier presence, and this has also been related to geothermal heat. As well as other study areas, the CRYOPERU sensor network includes 4 stations in the sector Coropuna-NE; 3 stations in Coropuna-SE; 3 stations in Chachani-SE and 3 stations in Misti-NW. The stations are at different altitudes, in an interval of 4300-6000 m. Each station has a thermometer to measure the air temperature (at a height of 0.50 m) and three thermometers to measure the ground temperature (at depths of 0.15, 0.30 and 1.00 m). The sensors are synchronized in GPS time and record the temperature every 30 minutes. Úbeda, J. et al (2012). Glacial and volcanic evolution on Nevado Coropuna (Tropical Andes) based on cosmogenic 36Cl surface exposure dating. EGU2012-3683-2. Úbeda, J. (2011). El impacto del cambio climático en los glaciares del complejo volcánico Nevado Coropuna (Cordillera Occidental de los Andes Centrales). PhD Thesis. Universidad Complutense de Madrid. 594 pp. http

Nyiragonga Volcano

NASA Image and Video Library

2002-02-01

This image of the Nyiragonga volcano eruption in the Congo was acquired on January 28, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. Image: A river of molten rock poured from the Nyiragongo volcano in the Congo on January 18, 2002, a day after it erupted, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. The flow continued into Lake Kivu. The lave flows are depicted in red on the image indicating they are still hot. Two of them flowed south form the volcano's summit and went through the town of Goma. Another flow can be seen at the top of the image, flowing towards the northwest. One of Africa's most notable volcanoes, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 killed 50 to 100 people, and several villages were destroyed. The image covers an area of 21 x 24 km and combines a thermal band in red, and two infrared bands in green and blue. http://photojournal.jpl.nasa.gov/catalog/PIA03462

Volcano flank instability in the Lesser Antilles Arc: Diversity of scale, processes, and temporal recurrence

NASA Astrophysics Data System (ADS)

Boudon, Georges; Le Friant, Anne; Komorowski, Jean-Christophe; Deplus, Christine; Semet, Michel P.

2007-08-01

The 1997 Boxing Day collapse, a remarkable feature of the ongoing eruption of Soufrière Hills on Montserrat, has prompted new interest in the study of volcano stability in the Lesser Antilles. Building on a few cases documented in the literature, we have now identified at least 47 flank collapse events on volcanoes of the Caribbean arc where this type of behavior is characteristic and repetitive. About 15 events occurred on active volcanoes within the last 12,000 years. In the northern part of the arc, flank collapses are repetitive, do not exceed 1 km3 in volume, occur in all directions, and are promoted by intense hydrothermal alteration and well-developed fracturing of the summit part of the edifices. In contrast, infrequent but large sector collapses, with volumes up to tens of km3, are typical of the southern volcanoes. They are always directed to the west as a result of the high overall slopes of the islands toward the deep back-arc Grenada Basin. Because Caribbean islands are small, a large part of the resulting debris avalanches have flowed into the sea thus contributing voluminous and sudden inputs of volcaniclastic sediments to the Grenada Basin. Deposits from such submarine flows have been identified during the recent AGUADOMAR and CARAVAL oceanographic cruises and traced to their source structures on land. Edifice collapses have a major influence on subsequent volcanic activity but also are of high concern because of their tsunamigenic potential.

High precision relocation of earthquakes at Iliamna Volcano, Alaska

USGS Publications Warehouse

Statz-Boyer, P.; Thurber, C.; Pesicek, J.; Prejean, S.

2009-01-01

In August 1996, a period of elevated seismicity commenced beneath Iliamna Volcano, Alaska. This activity lasted until early 1997, consisted of over 3000 earthquakes, and was accompanied by elevated emissions of volcanic gases. No eruption occurred and seismicity returned to background levels where it has remained since. We use waveform alignment with bispectrum-verified cross-correlation and double-difference methods to relocate over 2000 earthquakes from 1996 to 2005 with high precision (~ 100??m). The results of this analysis greatly clarify the distribution of seismic activity, revealing distinct features previously hidden by location scatter. A set of linear earthquake clusters diverges upward and southward from the main group of earthquakes. The events in these linear clusters show a clear southward migration with time. We suggest that these earthquakes represent either a response to degassing of the magma body, circulation of fluids due to exsolution from magma or heating of ground water, or possibly the intrusion of new dikes beneath Iliamna's southern flank. In addition, we speculate that the deeper, somewhat diffuse cluster of seismicity near and south of Iliamna's summit indicates the presence of an underlying magma body between about 2 and 4??km depth below sea level, based on similar features found previously at several other Alaskan volcanoes. ?? 2009 Elsevier B.V.

A model for radial dike emplacement in composite cones based on observations from Summer Coon volcano, Colorado, USA

USGS Publications Warehouse

Poland, Michael P.; Moats, W.P.; Fink, J.H.

2008-01-01

We mapped the geometry of 13 silicic dikes at Summer Coon, an eroded Oligocene stratovolcano in southern Colorado, to investigate various characteristics of radial dike emplacement in composite volcanoes. Exposed dikes are up to about 7 km in length and have numerous offset segments along their upper peripheries. Surprisingly, most dikes at Summer Coon increase in thickness with distance from the center of the volcano. Magma pressure in a dike is expected to lessen away from the pressurized source region, which would encourage a blade-like dike to decrease in thickness with distance from the center of the volcano. We attribute the observed thickness pattern as evidence of a driving pressure gradient, which is caused by decreasing host rock shear modulus and horizontal stress, both due to decreasing emplacement depths beneath the sloping flanks of the volcano. Based on data from Summer Coon, we propose that radial dikes originate at depth below the summit of a host volcano and follow steeply inclined paths towards the surface. Near the interface between volcanic cone and basement, which may represent a neutral buoyancy surface or stress barrier, magma is transported subhorizontally and radially away from the center of the volcano in blade-like dikes. The dikes thicken with increasing radial distance, and offset segments and fingers form along the upper peripheries of the intrusions. Eruptions may occur anywhere along the length of the dikes, but the erupted volume will generally be greater for dike-fed eruptions far from the center of the host volcano owing to the increase in driving pressure with distance from the source. Observed eruptive volumes, vent locations, and vent-area intrusions from inferred post-glacial dike-fed eruptions at Mount Adams, Washington, USA, support the proposed model. Hazards associated with radial dike emplacement are therefore greater for longer dikes that propagate to the outer flanks of a volcano. ?? Springer-Verlag 2007.

Ice-clad volcanoes

USGS Publications Warehouse

Waitt, Richard B.; Edwards, B.R.; Fountain, Andrew G.; Huggel, C.; Carey, Mark; Clague, John J.; Kääb, Andreas

2015-01-01

An icy volcano even if called extinct or dormant may be active at depth. Magma creeps up, crystallizes, releases gas. After decades or millennia the pressure from magmatic gas exceeds the resistance of overlying rock and the volcano erupts. Repeated eruptions build a cone that pokes one or two kilometers or more above its surroundings - a point of cool climate supporting glaciers. Ice-clad volcanic peaks ring the northern Pacific and reach south to Chile, New Zealand, and Antarctica. Others punctuate Iceland and Africa (Fig 4.1). To climb is irresistible - if only “because it’s there” in George Mallory’s words. Among the intrepid ascents of icy volcanoes we count Alexander von Humboldt’s attempt on 6270-meter Chimborazo in 1802 and Edward Whymper’s success there 78 years later. By then Cotopaxi steamed to the north.

Space Radar Image of Colombian Volcano

NASA Image and Video Library

1999-01-27

This is a radar image of a little known volcano in northern Colombia. The image was acquired on orbit 80 of space shuttle Endeavour on April 14, 1994, by NASA Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar SIR-C/X-SAR. The volcano near the center of the image is located at 5.6 degrees north latitude, 75.0 degrees west longitude, about 100 kilometers (65 miles) southeast of Medellin, Colombia. The conspicuous dark spot is a lake at the bottom of an approximately 3-kilometer-wide (1.9-mile) volcanic collapse depression or caldera. A cone-shaped peak on the bottom left (northeast rim) of the caldera appears to have been the source for a flow of material into the caldera. This is the northern-most known volcano in South America and because of its youthful appearance, should be considered dormant rather than extinct. The volcano's existence confirms a fracture zone proposed in 1985 as the northern boundary of volcanism in the Andes. The SIR-C/X-SAR image reveals another, older caldera further south in Colombia, along another proposed fracture zone. Although relatively conspicuous, these volcanoes have escaped widespread recognition because of frequent cloud cover that hinders remote sensing imaging in visible wavelengths. Four separate volcanoes in the Northern Andes nations of Colombia and Ecuador have been active during the last 10 years, killing more than 25,000 people, including scientists who were monitoring the volcanic activity. Detection and monitoring of volcanoes from space provides a safe way to investigate volcanism. The recognition of previously unknown volcanoes is important for hazard evaluations because a number of major eruptions this century have occurred at mountains that were not previously recognized as volcanoes. http://photojournal.jpl.nasa.gov/catalog/PIA01722

Volcanoes: Coming Up from Under.

ERIC Educational Resources Information Center

Science and Children, 1980

1980-01-01

Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how volcanoes are formed and how they are monitored. Words associated with volcanoes are listed and defined. (CS)

Exploring Geology on the World-Wide Web--Volcanoes and Volcanism.

ERIC Educational Resources Information Center

Schimmrich, Steven Henry; Gore, Pamela J. W.

1996-01-01

Focuses on sites on the World Wide Web that offer information about volcanoes. Web sites are classified into areas of Global Volcano Information, Volcanoes in Hawaii, Volcanoes in Alaska, Volcanoes in the Cascades, European and Icelandic Volcanoes, Extraterrestrial Volcanism, Volcanic Ash and Weather, and Volcano Resource Directories. Suggestions…

Overview for geologic field-trip guides to Mount Mazama, Crater Lake Caldera, and Newberry Volcano, Oregon

USGS Publications Warehouse

Bacon, Charles R.; Donnelly-Nolan, Julie M.; Jensen, Robert A.; Wright, Heather M.

2017-08-16

These field-trip guides were written for the occasion of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) quadrennial scientific assembly in Portland, Oregon, in August 2017. The guide to Mount Mazama and Crater Lake caldera is an updated and expanded version of the guide (Bacon, 1989) for part of an earlier IAVCEI trip to the southern Cascade Range. The guide to Newberry Volcano describes the stops included in the 2017 field trip. Crater Lake and Newberry are the two best-preserved and most recent calderas in the Cascades Volcanic Arc. Although located in different settings in the arc, with Crater Lake on the arc axis and Newberry in the rear-arc, both volcanoes are located at the intersection of the arc and the northwest corner region of the extensional Basin and Range Province.

San Cristobal Volcano, Nicaragua

NASA Technical Reports Server (NTRS)

1990-01-01

A white plume of smoke, from San Cristobal Volcano (13.0N, 87.5W) on the western coast of Nicaragua, blows westward along the Nicaraguan coast just south of the Gulf of Fonseca and the Honduran border. San Csistobal is a strato volcano some 1,745 meters high and is frequently active.

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

article title:  Eyjafjallajökull Volcano Plume Heights     View ... and stereo plume   Iceland's Eyjafjallajökull volcano produced its second major ash plume of 2010 beginning on May 7. Unlike ...

Volcano-Monitoring Instrumentation in the United States, 2008

USGS Publications Warehouse

Guffanti, Marianne; Diefenbach, Angela K.; Ewert, John W.; Ramsey, David W.; Cervelli, Peter F.; Schilling, Steven P.

2010-01-01

The United States is one of the most volcanically active countries in the world. According to the global volcanism database of the Smithsonian Institution, the United States (including its Commonwealth of the Northern Mariana Islands) is home to about 170 volcanoes that are in an eruptive phase, have erupted in historical time, or have not erupted recently but are young enough (eruptions within the past 10,000 years) to be capable of reawakening. From 1980 through 2008, 30 of these volcanoes erupted, several repeatedly. Volcano monitoring in the United States is carried out by the U.S. Geological Survey (USGS) Volcano Hazards Program, which operates a system of five volcano observatories-Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Hawaiian Volcano Observatory (HVO), Long Valley Observatory (LVO), and Yellowstone Volcano Observatory (YVO). The observatories issue public alerts about conditions and hazards at U.S. volcanoes in support of the USGS mandate under P.L. 93-288 (Stafford Act) to provide timely warnings of potential volcanic disasters to the affected populace and civil authorities. To make efficient use of the Nation's scientific resources, the volcano observatories operate in partnership with universities and other governmental agencies through various formal agreements. The Consortium of U.S. Volcano Observatories (CUSVO) was established in 2001 to promote scientific cooperation among the Federal, academic, and State agencies involved in observatory operations. Other groups also contribute to volcano monitoring by sponsoring long-term installation of geophysical instruments at some volcanoes for specific research projects. This report describes a database of information about permanently installed ground-based instruments used by the U.S. volcano observatories to monitor volcanic activity (unrest and eruptions). The purposes of this Volcano-Monitoring Instrumentation Database (VMID) are to (1) document the Nation's existing

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS

NASA Image and Video Library

1991-05-06

STS039-151-179 (28 April-6 May 1991) --- A large format frame of one of the USSR's volcanic complex (Kamchatka area) with the active volcano Klyuchevskaya (Kloo-chevs'-ska-ya), 15,584 feet in elevation. The last reported eruption of the volcano was on April 8, but an ash and steam plume extending to the south was observed by the STS-39 crew almost three weeks later. The south side of the volcano is dirty from the ash fall and landslide activity. The summit is clearly visible, as is the debris flow from an earlier eruption. Just north of the Kamchatka River is Shiveluch, a volcano which was active in early April. There are more than 100 volcanic edifices recognized on Kamchatka, with 15 classified as active.

Methane Hydrate Recovered From A Mud Volcano in Santa Monica Basin, Offshore Southern California

NASA Astrophysics Data System (ADS)

Normark, W. R.; Hein, J. R.; Powell, C. L.; Lorenson, T. D.; Lee, H. J.; Edwards, B. D.

2003-12-01

In July 2003, a short (2.1 m) piston core from the summit of a mud volcano recovered methane hydrate at a water depth of 813 m in Santa Monica Basin. The discovery core penetrated into in the hydrate as evidenced by chunks of ice and violent degassing of the core section between 162 and 212 cm depth. The core consists of shell hash and carbonate clasts (to 7-cm long) in silty mud. The methanogenic carbonates are of two types: massive, recrystallized nodular masses with an outer mm-thick sugary patina and a bivalve coquina with carbonate cement. Living clams including the genus Vesicomya, commonly found at cold-seep sites elsewhere, were recovered from the top of the core. Further sampling attempts using piston, gravity, and box corers, all of which were obtained within 15 m of the discovery core, recovered olive-brown silty mud with variable amounts of whole and fragmented bivalve shells and methanogenic carbonate fragments characteristic of cold-seep environments. Gases collected in cores adjacent to the discovery core contain elevated amounts of methane and trace amounts of heavier hydrocarbon gases, indicating some component from thermogenic sources. Hydrogen sulfide was also detected in these sediment samples. Vertical channels in one core may have served as fluid pathways. The existence of hydrate at such a shallow depth in the sediment was unexpected, however, the presence of Vesicomya and hydrogen sulfide indicate that the mud volcano is a site of active methane venting. The mud volcano, which is about 24 km west-southwest of Redondo Beach, is about 300 m in diameter at the base. No internal structure is resolved on either high resolution deep-tow boomer or single-channel air-gun profiles, most likely as a result of the gas content and sediment deformation. The diapiric structure has ascended through well-bedded sediment on the lower slope of the basin, producing as much as 30 m of bathymetric relief. It is located in an area where strike-slip motion along

The Volcano Adventure Guide

NASA Astrophysics Data System (ADS)

Lopes, Rosaly

2005-02-01

This guide contains vital information for anyone wishing to visit, explore, and photograph active volcanoes safely and enjoyably. Following an introduction that discusses eruption styles of different types of volcanoes and how to prepare for an exploratory trip that avoids volcanic dangers, the book presents guidelines to visiting 42 different volcanoes around the world. It is filled with practical information that includes tour itineraries, maps, transportation details, and warnings of possible non-volcanic dangers. Three appendices direct the reader to a wealth of further volcano resources in a volume that will fascinate amateur enthusiasts and professional volcanologists alike. Rosaly Lopes is a planetary geology and volcanology specialist at the NASA Jet Propulsion Laboratory in California. In addition to her curatorial and research work, she has lectured extensively in England and Brazil and written numerous popular science articles. She received a Latinas in Science Award from the Comision Feminil Mexicana Nacional in 1991 and since 1992, has been a co-organizer of the United Nations/European Space Agency/The Planetary Society yearly conferences on Basic Science for the Benefit of Developing Countries.

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS

NASA Technical Reports Server (NTRS)

1991-01-01

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS (56.0N, 160.5E) is one of several active volcanoes in the CIS and is 15,584 ft. in elevation. Fresh ash fall on the south side of the caldera can be seen as a dirty smudge on the fresh snowfall. Just to the north of the Kamchatka River is Shiveluch, a volcano which had been active a short time previously. There are more than 100 volcanic edifices recognized on Kamchatka, 15 of which are still active.

Preliminary Volcano-Hazard Assessment for Redoubt Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Dorava, Joseph M.; Miller, Thomas P.; Neal, Christina A.; McGimsey, Robert G.

1997-01-01

Redoubt Volcano is a stratovolcano located within a few hundred kilometers of more than half of the population of Alaska. This volcano has erupted explosively at least six times since historical observations began in 1778. The most recent eruption occurred in 1989-90 and similar eruptions can be expected in the future. The early part of the 1989-90 eruption was characterized by explosive emission of substantial volumes of volcanic ash to altitudes greater than 12 kilometers above sea level and widespread flooding of the Drift River valley. Later, the eruption became less violent, as developing lava domes collapsed, forming short-lived pyroclastic flows associated with low-level ash emission. Clouds of volcanic ash had significant effects on air travel as they drifted across Alaska, over Canada, and over parts of the conterminous United States causing damage to jet aircraft. Economic hardships were encountered by the people of south-central Alaska as a result of ash fallout. Based on new information gained from studies of the 1989-90 eruption, an updated assessment of the principal volcanic hazards is now possible. Volcanic hazards from a future eruption of Redoubt Volcano require public awareness and planning so that risks to life and property are reduced as much as possible.

The chronology of the martian volcanoes

NASA Technical Reports Server (NTRS)

Plescia, J. B.; Saunders, R. S.

1979-01-01

The volcanoes of Mars have been divided into three groups based on morphology: basaltic shields, domes and composite cones, and highland patera. A fourth group can be added to include the volcano-tectonic depressions. Using crater counts and the absolute chronology of Soderblom, an attempt is made to estimate the history of the volcanoes. Early in the martian history, about 2.5 b.y. ago, all three styles of volcanoes were active at various locations on the surface. At approximately 1.7-1.8 b.y. ago a transition occurred in the style and loci of volcanic construction. Volcanoes of younger age appear to be only of the basaltic shield group and are restricted to the Tharsis region. This same transition was noted by a change in the style of the basaltic shield group. Older shields were small low features, while the younger shields are significantly broader and taller.

Thematic mapper studies of Andean volcanoes

NASA Technical Reports Server (NTRS)

Francis, P. W.

1986-01-01

The primary objective was to identify all the active volcanoes in the Andean region of Bolivia. Morphological features of the Tata Sabaya volcano, Bolivia, were studied with the thematic mapper. Details include marginal levees on lava and pyroclastic flows, and summit crater structure. Valley glacier moraine deposits, not easily identified on the multispectral band scanner, were also unambiguous, and provide useful marker horizons on large volcanic edifices which were built up in preglacial times but which were active subsequently. With such high resolution imagery, it is not only possible to identify potentially active volcanoes, but also to use standard photogeological interpretation to outline the history of individual volcanoes.

Costa Rica's Chain of laterally collapsed volcanoes.

NASA Astrophysics Data System (ADS)

Duarte, E.; Fernandez, E.

2007-05-01

From the NW extreme to the SW end of Costa Rica's volcanic backbone, a number of laterally collapsed volcanoes can be observed. Due to several factors, attention has been given to active volcanoes disregarding the importance of collapsed features in terms of assessing volcanic hazards for future generations around inhabited volcanoes. In several cases the typical horseshoe shape amphitheater-like depression can be easily observed. In other cases due to erosion, vegetation, topography, seismic activity or drastic weather such characteristics are not easily recognized. In the order mentioned above appear: Orosi-Cacao, Miravalles, Platanar, Congo, Von Frantzius, Cacho Negro and Turrialba volcanoes. Due to limited studies on these structures it is unknown if sector collapse occurred in one or several phases. Furthermore, in the few studied cases no evidence has been found to relate collapses to actual eruptive episodes. Detailed studies on the deposits and materials composing dome-like shapes will shed light on unsolved questions about petrological and chemical composition. Volume, form and distance traveled by deposits are part of the questions surrounding most of these collapsed volcanoes. Although most of these mentioned structures are extinct, at least Irazú volcano (active volcano) has faced partial lateral collapses recently. It did presented strombolian activity in the early 60s. Collapse scars show on the NW flank show important mass removal in historic and prehistoric times. Moreover, in 1994 a minor hydrothermal explosion provoked the weakening of a deeply altered wall that holds a crater lake (150m diameter, 2.6x106 ). A poster will depict images of the collapsed volcanoes named above with mayor descriptive characteristics. It will also focus on the importance of deeper studies to assess the collapse potential of Irazú volcano with related consequences. Finally, this initiative will invite researchers interested in such topic to join future studies in

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

article title:  Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic   ... that occurred in late March 2010, the Eyjafjallajökull Volcano in Iceland began erupting again on April 14, 2010. The resulting ash ...

Extensive, water-rich magma reservoir beneath southern Montserrat

NASA Astrophysics Data System (ADS)

Edmonds, M.; Kohn, S. C.; Hauri, E. H.; Humphreys, M. C. S.; Cassidy, M.

2016-05-01

South Soufrière Hills and Soufrière Hills volcanoes are 2 km apart at the southern end of the island of Montserrat, West Indies. Their magmas are distinct geochemically, despite these volcanoes having been active contemporaneously at 131-129 ka. We use the water content of pyroxenes and melt inclusion data to reconstruct the bulk water contents of magmas and their depth of storage prior to eruption. Pyroxenes contain up to 281 ppm H2O, with significant variability between crystals and from core to rim in individual crystals. The Al content of the enstatites from Soufrière Hills Volcano (SHV) is used to constrain melt-pyroxene partitioning for H2O. The SHV enstatite cores record melt water contents of 6-9 wt%. Pyroxene and melt inclusion water concentration pairs from South Soufriere Hills basalts independently constrain pyroxene-melt partitioning of water and produces a comparable range in melt water concentrations. Melt inclusions recorded in plagioclase and in pyroxene contain up to 6.3 wt% H2O. When combined with realistic melt CO2 contents, the depth of magma storage for both volcanoes ranges from 5 to 16 km. The data are consistent with a vertically protracted crystal mush in the upper crust beneath the southern part of Montserrat which contains heterogeneous bodies of eruptible magma. The high water contents of the magmas suggest that they contain a high proportion of exsolved fluids, which has implications for the rheology of the mush and timescales for mush reorganisation prior to eruption. A depletion in water in the outer 50-100 μm of a subset of pyroxenes from pumices from a Vulcanian explosion at Soufrière Hills in 2003 is consistent with diffusive loss of hydrogen during magma ascent over 5-13 h. These timescales are similar to the mean time periods between explosions in 1997 and in 2003, raising the possibility that the driving force for this repetitive explosive behaviour lies not in the shallow system, but in the deeper parts of a vertically

Mechanical coupling between earthquakes and volcanoes inferred from stress transfer models: evidence from Vesuvio, Etna and Alban Hills (Italy)

NASA Astrophysics Data System (ADS)

Cocco, M.; Feuillet, N.; Nostro, C.; Musumeci, C.

2003-04-01

We investigate the mechanical interactions between tectonic faults and volcanic sources through elastic stress transfer and discuss the results of several applications to Italian active volcanoes. We first present the stress modeling results that point out a two-way coupling between Vesuvius eruptions and historical earthquakes in Southern Apennines, which allow us to provide a physical interpretation of their statistical correlation. Therefore, we explore the elastic stress interaction between historical eruptions at the Etna volcano and the largest earthquakes in Eastern Sicily and Calabria. We show that the large 1693 seismic event caused an increase of compressive stress along the rift zone, which can be associated to the lack of flank eruptions of the Etna volcano for about 70 years after the earthquake. Moreover, the largest Etna eruptions preceded by few decades the large 1693 seismic event. Our modeling results clearly suggest that all these catastrophic events are tectonically coupled. We also investigate the effect of elastic stress perturbations on the instrumental seismicity caused by magma inflation at depth both at the Etna and at the Alban Hills volcanoes. In particular, we model the seismicity pattern at the Alban Hills volcano (central Italy) during a seismic swarm occurred in 1989-90 and we interpret it in terms of Coulomb stress changes caused by magmatic processes in an extensional tectonic stress field. We verify that the earthquakes occur in areas of Coulomb stress increase and that their faulting mechanisms are consistent with the stress perturbation induced by the volcanic source. Our results suggest a link between faults and volcanic sources, which we interpret as a tectonic coupling explaining the seismicity in a large area surrounding the volcanoes.

A Controversial Source for a 1.2-1.5 km3 Debris Avalanche Deposit in Northern Ecuador: A Case Study of Cubilche Volcano

NASA Astrophysics Data System (ADS)

Mulas, M.; Bowman, L.; Roverato, M.; Larrea Marquez, P.; Casado, I.

2017-12-01

Debris avalanche deposits (DAD) are common products of catastrophic volcanic edifice collapses. These failure events leave peculiar horseshoe-shaped scars on the summits of stratovolcanoes. Cubilche Volcano (3826 masl), located S of the city of Ibarra (Imbabura Province) and E of the dormant Imbabura volcano, displays a distinct horseshoe-shaped scar towards the N. This post-collapse edifice that we name "Old Cubilche Volcano" (OCV) hosts an additional edifice, "Young Cubilche Volcano" (YCV), which partially covers the southern flank of OCV. Knowledge of Cubilche is critical because of its close proximity to the provincial capital of Ibarra. In fact, Imbabura edifice was built over the northwestern slope of OCV and partially covered it. The studied DAD (unknown age) has been recently linked to Imbabura Volcano as a product of its northwestern sector collapse (LePennec et al., 2011). Alternatively, previous work proposed that the DAD, covering 80 km2 and reaching >13 km distance with an estimated volume of 1.6 km3, was the product of the older OCV (Ruiz, 2003). To constrain the source of the DAD, detailed fieldwork with granulometric, petrological, and geochemical analyses of the deposit was conducted. Preliminary data points to Cubilche as the most likely source for this DAD in accordance with Ruiz (2003). The shaded relief image of the present day OCV shows that the morphology of the volcano is well-preserved on its southern, eastern, and western flanks. This allows the reconstruction of the morphology of OCV prior to the collapse through interpolation of elevation and altitude data of the preserved flanks. A DEM of the present day topography (12m horizontal resolution) obtained from TanDEM-X data was used for extrapolating the morphology. This methodology shows that the post-collapse base of the amphitheater was reconstructed by removing the relief of the present day YCV. The reconstructed topography of OCV shows that it could have been a symmetric cone, reaching

Sakura-jima volcano in Japan as seen from STS-66 Atlantis

NASA Technical Reports Server (NTRS)

1994-01-01

One of the world's most active volcanoes, Sakura-jima in southern-most Kyushu, Japan, erupts dozens of times a year. Volcanic eruptions are so much a part of of daily life in the city of Kagoshima (across the bay and west of Sakura-jima), that school children wear hard hats to school. This photo provides a nice clear view of Sakura-jima on a quiet day - only a plume of steam rises from the summit crater. The summit region is covered with gray ash from the frequent eruptions, and some of the rivers cutting down the mountain (especially the western drainages) appear to be filled with volcanic debris.

Sakura-jima volcano in Japan as seen from STS-66 Atlantis

NASA Image and Video Library

1994-11-14

One of the world's most active volcanoes, Sakura-jima in southern-most Kyushu, Japan, erupts dozens of times a year. Volcanic eruptions are so much a part of of daily life in the city of Kagoshima (across the bay and west of Sakura-jima), that school children wear hard hats to school. This photo provides a nice clear view of Sakura-jima on a quiet day - only a plume of steam rises from the summit crater. The summit region is covered with gray ash from the frequent eruptions, and some of the rivers cutting down the mountain (especially the western drainages) appear to be filled with volcanic debris.

Earthquake sources near Uturuncu Volcano

NASA Astrophysics Data System (ADS)

Keyson, L.; West, M. E.

2013-12-01

Uturuncu, located in southern Bolivia near the Chile and Argentina border, is a dacitic volcano that was last active 270 ka. It is a part of the Altiplano-Puna Volcanic Complex, which spans 50,000 km2 and is comprised of a series of ignimbrite flare-ups since ~23 ma. Two sets of evidence suggest that the region is underlain by a significant magma body. First, seismic velocities show a low velocity layer consistent with a magmatic sill below depths of 15-20 km. This inference is corroborated by high electrical conductivity between 10km and 30km. This magma body, the so called Altiplano-Puna Magma Body (APMB) is the likely source of volcanic activity in the region. InSAR studies show that during the 1990s, the volcano experienced an average uplift of about 1 to 2 cm per year. The deformation is consistent with an expanding source at depth. Though the Uturuncu region exhibits high rates of crustal seismicity, any connection between the inflation and the seismicity is unclear. We investigate the root causes of these earthquakes using a temporary network of 33 seismic stations - part of the PLUTONS project. Our primary approach is based on hypocenter locations and magnitudes paired with correlation-based relative relocation techniques. We find a strong tendency toward earthquake swarms that cluster in space and time. These swarms often last a few days and consist of numerous earthquakes with similar source mechanisms. Most seismicity occurs in the top 10 kilometers of the crust and is characterized by well-defined phase arrivals and significant high frequency content. The frequency-magnitude relationship of this seismicity demonstrates b-values consistent with tectonic sources. There is a strong clustering of earthquakes around the Uturuncu edifice. Earthquakes elsewhere in the region align in bands striking northwest-southeast consistent with regional stresses.

Special issue: The changing shapes of active volcanoes: Recent results and advances in volcano geodesy

USGS Publications Warehouse

Poland, Michael P.; Newman, Andrew V.

2006-01-01

The 18 papers herein report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide a proper context for these studies, we offer a short review of the evolution of volcano geodesy, as well as a case study that highlights recent advances in the field by comparing the geodetic response to recent eruptive episodes at Mount St. Helens. Finally, we point out a few areas that continue to challenge the volcano geodesy community, some of which are addressed by the papers that follow and which undoubtedly will be the focus of future research for years to come.

Late Holocene volcanism at Medicine Lake Volcano, northern California Cascades

USGS Publications Warehouse

Donnelly-Nolan, Julie M.; Champion, Duane E.; Grove, Timothy L.

2016-05-23

Late Holocene volcanism at Medicine Lake volcano in the southern Cascades arc exhibited widespread and compositionally diverse magmatism ranging from basalt to rhyolite. Nine well-characterized eruptions have taken place at this very large rear-arc volcano since 5,200 years ago, an eruptive frequency greater than nearly all other Cascade volcanoes. The lavas are widely distributed, scattered over an area of ~300 km2 across the >2,000-km2 volcano. The eruptions are radiocarbon dated and the ages are also constrained by paleomagnetic data that provide strong evidence that the volcanic activity occurred in three distinct episodes at ~1 ka, ~3 ka, and ~5 ka. The ~1-ka final episode produced a variety of compositions including west- and north-flank mafic flows interspersed in time with fissure rhyolites erupted tangential to the volcano’s central caldera, including the youngest and most spectacular lava flow at the volcano, the ~950-yr-old compositionally zoned Glass Mountain flow. At ~3 ka, a north-flank basalt eruption was followed by an andesite eruption 27 km farther south that contains quenched basalt inclusions. The ~5-ka episode produced two caldera-focused dacitic eruptions. Quenched magmatic inclusions record evidence of intrusions that did not independently reach the surface. The inclusions are present in five andesitic, dacitic, and rhyolitic host lavas, and were erupted in each of the three episodes. Compositional and mineralogic evidence from mafic lavas and inclusions indicate that both tholeiitic (dry) and calcalkaline (wet) parental magmas were present. Petrologic evidence records the operation of complex, multi-stage processes including fractional crystallization, crustal assimilation, and magma mixing. Experimental evidence suggests that magmas were stored at 3 to 6 km depth prior to eruption, and that both wet and dry parental magmas were involved in generating the more silicic magmas. The broad distribution of eruptive events and the relative

Three active volcanoes in China and their hazards

NASA Astrophysics Data System (ADS)

Wei, H.; Sparks, R. S. J.; Liu, R.; Fan, Q.; Wang, Y.; Hong, H.; Zhang, H.; Chen, H.; Jiang, C.; Dong, J.; Zheng, Y.; Pan, Y.

2003-02-01

The active volcanoes in China are located in the Changbaishan area, Jingbo Lake, Wudalianchi, Tengchong and Yutian. Several of these volcanoes have historical records of eruption and geochronological evidence of Holocene activity. Tianchi Volcano is a well-preserved Cenozoic polygenetic central volcano, and, due to its recent history of powerful explosive eruptions of felsic magmas, with over 100,000 people living on its flanks is a high-risk volcano. Explosive eruptions at 4000 and 1000 years BP involved plinian and ignimbrite phases. The Millennium eruption (1000 years BP) involved at least 20-30 km 3 of magma and was large enough to have a global impact. There are 14 Cenozoic monogenetic scoria cones and associated lavas with high-K basalt composition in the Wudalianchi volcanic field. The Laoheishan and Huoshaoshan cones and related lavas were formed in 1720-1721 and 1776 AD. There are three Holocene volcanoes, Dayingshan, Maanshan, and Heikongshan, among the 68 Quaternary volcanoes in the Tengchong volcanic province. Three of these volcanoes are identified as active, based on geothermal activity, geophysical evidence for magma, and dating of young volcanic rocks. Future eruptions of these Chinese volcanoes pose a significant threat to hundreds of thousands of people and are likely to cause substantial economic losses.

Alaska volcanoes guidebook for teachers

USGS Publications Warehouse

Adleman, Jennifer N.

2011-01-01

Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at

Volcanoes and the Environment

NASA Astrophysics Data System (ADS)

Marti, Edited By Joan; Ernst, Gerald G. J.

2005-10-01

Volcanoes and the Environment is a comprehensive and accessible text incorporating contributions from some of the world's authorities in volcanology. This book is an indispensable guide for those interested in how volcanism affects our planet's environment. It spans a wide variety of topics from geology to climatology and ecology; it also considers the economic and social impacts of volcanic activity on humans. Topics covered include how volcanoes shape the environment, their effect on the geological cycle, atmosphere and climate, impacts on health of living on active volcanoes, volcanism and early life, effects of eruptions on plant and animal life, large eruptions and mass extinctions, and the impact of volcanic disasters on the economy. This book is intended for students and researchers interested in environmental change from the fields of earth and environmental science, geography, ecology and social science. It will also interest policy makers and professionals working on natural hazards. An all-inclusive text that goes beyond the geological working of volcanoes to consider their environmental and sociological impacts Each chapter is written by one of the world's leading authorities on the subject Accessible to students and researchers from a wide variety of backgrounds

The 2014 eruptions of Pavlof Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Haney, Matthew M.; Wallace, Kristi; Cameron, Cheryl E.; Schneider, David J.

2017-12-22

Pavlof Volcano is one of the most frequently active volcanoes in the Aleutian Island arc, having erupted more than 40 times since observations were first recorded in the early 1800s . The volcano is located on the Alaska Peninsula (lat 55.4173° N, long 161.8937° W), near Izembek National Wildlife Refuge. The towns and villages closest to the volcano are Cold Bay, Nelson Lagoon, Sand Point, and King Cove, which are all within 90 kilometers (km) of the volcano (fig. 1). Pavlof is a symmetrically shaped stratocone that is 2,518 meters (m) high, and has about 2,300 m of relief. The volcano supports a cover of glacial ice and perennial snow roughly 2 to 4 cubic kilometers (km3) in volume, which is mantled by variable amounts of tephra fall, rockfall debris, and pyroclastic-flow deposits produced during historical eruptions. Typical Pavlof eruptions are characterized by moderate amounts of ash emission, lava fountaining, spatter-fed lava flows, explosions, and the accumulation of unstable mounds of spatter on the upper flanks of the volcano. The accumulation and subsequent collapse of spatter piles on the upper flanks of the volcano creates hot granular avalanches, which erode and melt snow and ice, and thereby generate watery debris-flow and hyperconcentrated-flow lahars. Seismic instruments were first installed on Pavlof Volcano in the early 1970s, and since then eruptive episodes have been better characterized and specific processes have been documented with greater certainty. The application of remote sensing techniques, including the use of infrasound data, has also aided the study of more recent eruptions. Although Pavlof Volcano is located in a remote part of Alaska, it is visible from Cold Bay, Sand Point, and Nelson Lagoon, making distal observations of eruptive activity possible, weather permitting. A busy air-travel corridor that is utilized by a numerous transcontinental and regional air carriers passes near Pavlof Volcano. The frequency of air travel

Diffuse degassing at Longonot volcano, Kenya: Implications for CO2 flux in continental rifts

NASA Astrophysics Data System (ADS)

Robertson, Elspeth; Biggs, Juliet; Edmonds, Marie; Clor, Laura; Fischer, Tobias P.; Vye-Brown, Charlotte; Kianji, Gladys; Koros, Wesley; Kandie, Risper

2016-11-01

Magma movement, fault structures and hydrothermal systems influence volatile emissions at rift volcanoes. Longonot is a Quaternary caldera volcano located in the southern Kenyan Rift, where regional extension controls recent shallow magma ascent. Here we report the results of a soil carbon dioxide (CO2) survey in the vicinity of Longonot volcano, as well as fumarolic gas compositions and carbon isotope data. The total non-biogenic CO2 degassing is estimated at < 300 kg d- 1, and is largely controlled by crater faults and fractures close to the summit. Thus, recent volcanic structures, rather than regional tectonics, control fluid pathways and degassing. Fumarolic gases are characterised by a narrow range in carbon isotope ratios (δ13C), from - 4.7‰ to - 6.4‰ (vs. PDB) suggesting a magmatic origin with minor contributions from biogenic CO2. Comparison with other degassing measurements in the East African Rift shows that records of historical eruptions or unrest do not correspond directly to the magnitude of CO2 flux from volcanic centres, which may instead reflect the current size and characteristics of the subsurface magma reservoir. Interestingly, the integrated CO2 flux from faulted rift basins is reported to be an order of magnitude higher than that from any of the volcanic centres for which CO2 surveys have so far been reported.

Intense Seismic Activity at Chiles and Cerro Negro Volcanoes on the Colombia-Ecuador Border

NASA Astrophysics Data System (ADS)

Torres, R. A.; Cadena, O.; Gomez, D.; Ruiz, M. C.; Prejean, S. G.; Lyons, J. J.; White, R. A.

2015-12-01

The region of Chiles and Cerro Negro volcanoes, located on the Colombian-Ecuadorian border, has experienced an ongoing seismic swarm beginning in Aug. 2013. Based on concern for local residents and authorities, a cooperative broadband monitoring network was installed by the Servicio Geológico Colombiano in Colombia and the Instituto Geofísico of the Escuela Politécnica Nacional in Ecuador. Since November 2013 more than 538,000 earthquakes were recorded; although since May 2015 the seismicity has decreased significantly to an average of 70 events per day. Three large earthquake swarms with increasing energy occurred in Aug.-Oct. 2013, March-May 2014, and Sept.-Dec. 2014. By the end of 2014, roughly 400 earthquakes greater than M 3 had occurred with a maximum rate of 8000 earthquakes per day. The largest earthquake was a 5.6 ML on Oct. 20, 2014. This event produced an InSAR coseismic deformation of ~23 cm (S. Ebmeier, personal communication). Most events are typical brittle failure volcano-tectonic (VT) earthquakes that are located in a cluster beneath the southern flank of Chiles volcano, with depths between 1.5 and 10 km. Although the great majority of earthquakes are VT, some low-frequency (LF, ~0.5 Hz) and very-low-frequency (VLF) events have occurred. Particle motion analysis suggests that the VLF source migrated with time. While a VLF on Oct. 15, 2014 was located south of Chiles volcano, near the InSAR source, the VLF registered on Feb. 14, 2015 was likely located very close to Chiles Volcano. We infer that magma intrusion and resulting fluid exsolution at depths greater than 5 km are driving seismicity in the Chiles-Cerro Negro region. However earthquakes are failing in a manner consistent with regional tectonics. Relative relocations reveal a structure consistent with mapped regional faults. Thus seismicity is likely controlled by an interaction of magmatic and tectonic processes. Because the regional stress field is highly compressional and the volcanoes

Catalogue of Icelandic Volcanoes

NASA Astrophysics Data System (ADS)

Ilyinskaya, Evgenia; Larsen, Gudrun; Gudmundsson, Magnus T.; Vogfjord, Kristin; Pagneux, Emmanuel; Oddsson, Bjorn; Barsotti, Sara; Karlsdottir, Sigrun

2016-04-01

The Catalogue of Icelandic Volcanoes is a newly developed open-access web resource in English intended to serve as an official source of information about active volcanoes in Iceland and their characteristics. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the effort of FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite. Volcanic activity in Iceland occurs on volcanic systems that usually comprise a central volcano and fissure swarm. Over 30 systems have been active during the Holocene (the time since the end of the last glaciation - approximately the last 11,500 years). In the last 50 years, over 20 eruptions have occurred in Iceland displaying very varied activity in terms of eruption styles, eruptive environments, eruptive products and the distribution lava and tephra. Although basaltic eruptions are most common, the majority of eruptions are explosive, not the least due to magma-water interaction in ice-covered volcanoes. Extensive research has taken place on Icelandic volcanism, and the results reported in numerous scientific papers and other publications. In 2010, the International Civil Aviation Organisation (ICAO) funded a 3 year project to collate the current state of knowledge and create a comprehensive catalogue readily available to decision makers, stakeholders and the general public. The work on the Catalogue began in 2011, and was then further supported by the Icelandic government and the EU through the FP7 project FUTUREVOLC. The Catalogue of Icelandic Volcanoes is a collaboration of the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere. The Catalogue is built up of chapters with texts and various

Pattern recognition applied to seismic signals of Llaima volcano (Chile): An evaluation of station-dependent classifiers

NASA Astrophysics Data System (ADS)

Curilem, Millaray; Huenupan, Fernando; Beltrán, Daniel; San Martin, Cesar; Fuentealba, Gustavo; Franco, Luis; Cardona, Carlos; Acuña, Gonzalo; Chacón, Max; Khan, M. Salman; Becerra Yoma, Nestor

2016-04-01

Automatic pattern recognition applied to seismic signals from volcanoes may assist seismic monitoring by reducing the workload of analysts, allowing them to focus on more challenging activities, such as producing reports, implementing models, and understanding volcanic behaviour. In a previous work, we proposed a structure for automatic classification of seismic events in Llaima volcano, one of the most active volcanoes in the Southern Andes, located in the Araucanía Region of Chile. A database of events taken from three monitoring stations on the volcano was used to create a classification structure, independent of which station provided the signal. The database included three types of volcanic events: tremor, long period, and volcano-tectonic and a contrast group which contains other types of seismic signals. In the present work, we maintain the same classification scheme, but we consider separately the stations information in order to assess whether the complementary information provided by different stations improves the performance of the classifier in recognising seismic patterns. This paper proposes two strategies for combining the information from the stations: i) combining the features extracted from the signals from each station and ii) combining the classifiers of each station. In the first case, the features extracted from the signals from each station are combined forming the input for a single classification structure. In the second, a decision stage combines the results of the classifiers for each station to give a unique output. The results confirm that the station-dependent strategies that combine the features and the classifiers from several stations improves the classification performance, and that the combination of the features provides the best performance. The results show an average improvement of 9% in the classification accuracy when compared with the station-independent method.

Volcano warning systems: Chapter 67

USGS Publications Warehouse

Gregg, Chris E.; Houghton, Bruce F.; Ewert, John W.

2015-01-01

Messages conveying volcano alert level such as Watches and Warnings are designed to provide people with risk information before, during, and after eruptions. Information is communicated to people from volcano observatories and emergency management agencies and from informal sources and social and environmental cues. Any individual or agency can be both a message sender and a recipient and multiple messages received from multiple sources is the norm in a volcanic crisis. Significant challenges to developing effective warning systems for volcanic hazards stem from the great diversity in unrest, eruption, and post-eruption processes and the rapidly advancing digital technologies that people use to seek real-time risk information. Challenges also involve the need to invest resources before unrest to help people develop shared mental models of important risk factors. Two populations of people are the target of volcano notifications–ground- and aviation-based populations, and volcano warning systems must address both distinctly different populations.

Volcano hazards in the Three Sisters region, Oregon

USGS Publications Warehouse

Scott, William E.; Iverson, R.M.; Schilling, S.P.; Fisher, B.J.

2001-01-01

Three Sisters is one of three potentially active volcanic centers that lie close to rapidly growing communities and resort areas in Central Oregon. Two types of volcanoes exist in the Three Sisters region and each poses distinct hazards to people and property. South Sister, Middle Sister, and Broken Top, major composite volcanoes clustered near the center of the region, have erupted repeatedly over tens of thousands of years and may erupt explosively in the future. In contrast, mafic volcanoes, which range from small cinder cones to large shield volcanoes like North Sister and Belknap Crater, are typically short-lived (weeks to centuries) and erupt less explosively than do composite volcanoes. Hundreds of mafic volcanoes scattered through the Three Sisters region are part of a much longer zone along the High Cascades of Oregon in which birth of new mafic volcanoes is possible. This report describes the types of hazardous events that can occur in the Three Sisters region and the accompanying volcano-hazard-zonation map outlines areas that could be at risk from such events. Hazardous events include landslides from the steep flanks of large volcanoes and floods, which need not be triggered by eruptions, as well as eruption-triggered events such as fallout of tephra (volcanic ash) and lava flows. A proximal hazard zone roughly 20 kilometers (12 miles) in diameter surrounding the Three Sisters and Broken Top could be affected within minutes of the onset of an eruption or large landslide. Distal hazard zones that follow river valleys downstream from the Three Sisters and Broken Top could be inundated by lahars (rapid flows of water-laden rock and mud) generated either by melting of snow and ice during eruptions or by large landslides. Slow-moving lava flows could issue from new mafic volcanoes almost anywhere within the region. Fallout of tephra from eruption clouds can affect areas hundreds of kilometers (miles) downwind, so eruptions at volcanoes elsewhere in the

Volcanoes Distribution in Linear Segmentation of Mariana Arc

NASA Astrophysics Data System (ADS)

Andikagumi, H.; Macpherson, C.; McCaffrey, K. J. W.

2016-12-01

A new method has been developed to describe better volcanoes distribution pattern within Mariana Arc. A previous study assumed the distribution of volcanoes in the Mariana Arc is described by a small circle distribution which reflects the melting processes in a curved subduction zone. The small circle fit to this dataset used in the study, comprised 12 -mainly subaerial- volcanoes from Smithsonian Institute Global Volcanism Program, was reassessed by us to have a root-mean-square misfit of 2.5 km. The same method applied to a more complete dataset from Baker et al. (2008), consisting 37 subaerial and submarine volcanoes, resulted in an 8.4 km misfit. However, using the Hough Transform method on the larger dataset, lower misfits of great circle segments were achieved (3.1 and 3.0 km) for two possible segments combination. The results indicate that the distribution of volcanoes in the Mariana Arc is better described by a great circle pattern, instead of small circle. Variogram and cross-variogram analysis on volcano spacing and volume shows that there is spatial correlation between volcanoes between 420 and 500 km which corresponds to the maximum segmentation lengths from Hough Transform (320 km). Further analysis of volcano spacing by the coefficient of variation (Cv), shows a tendency toward not-random distribution as the Cv values are closer to zero than one. These distributions are inferred to be associated with the development of normal faults at the back arc as their Cv values also tend towards zero. To analyse whether volcano spacing is random or not, Cv values were simulated using a Monte Carlo method with random input. Only the southernmost segment has allowed us to reject the null hypothesis that volcanoes are randomly spaced at 95% confidence level by 0.007 estimated probability. This result shows infrequent regularity in volcano spacing by chance so that controlling factor in lithospheric scale should be analysed with different approach (not from random

Mobile Response Team Saves Lives in Volcano Crises

USGS Publications Warehouse

Ewert, John W.; Miller, C. Dan; Hendley, James W.; Stauffer, Peter H.

1997-01-01

The world's only volcano crisis response team, organized and operated by the USGS, can be quickly mobilized to assess and monitor hazards at volcanoes threatening to erupt. Since 1986, the team has responded to more than a dozen volcano crises as part of the Volcano Disaster Assistance Program (VDAP), a cooperative effort with the Office of Foreign Disaster Assistance of the U.S. Agency for International Development. The work of USGS scientists with VDAP has helped save countless lives, and the valuable lessons learned are being used to reduce risks from volcano hazards in the United States.

SO2 camera measurements at Lastarria volcano and Lascar volcano in Chile

NASA Astrophysics Data System (ADS)

Lübcke, Peter; Bobrowski, Nicole; Dinger, Florian; Klein, Angelika; Kuhn, Jonas; Platt, Ulrich

2015-04-01

The SO2 camera is a remote-sensing technique that measures volcanic SO2 emissions via the strong SO2 absorption structures in the UV using scattered solar radiation as a light source. The 2D-imagery (usually recorded with a frame rate of up to 1 Hz) allows new insights into degassing processes of volcanoes. Besides the large advantage of high frequency sampling the spatial resolution allows to investigate SO2 emissions from individual fumaroles and not only the total SO2 emission flux of a volcano, which is often dominated by the volcanic plume. Here we present SO2 camera measurements that were made during the CCVG workshop in Chile in November 2014. Measurements were performed at Lastarria volcano, a 5700 m high stratovolcano and Lascar volcano, a 5600 m high stratovolcano both in northern Chile on 21 - 22 November, 2014 and on 26 - 27 November, 2014, respectively. At both volcanoes measurements were conducted from a distance of roughly 6-7 km under close to ideal conditions (low solar zenith angle, a very dry and cloudless atmosphere and an only slightly condensed plume). However, determination of absolute SO2 emission rates proves challenging as part of the volcanic plume hovered close to the ground. The volcanic plume therefore is in front of the mountain in our camera images. An SO2 camera system consisting of a UV sensitive CCD and two UV band-pass filters (centered at 315 nm and 330 nm) was used. The two band-pass filters are installed in a rotating wheel and images are taken with both filter sequentially. The instrument used a CCD with 1024 x 1024 pixels and an imaging area of 13.3 mm x 13.3 mm. In combination with the focal length of 32 mm this results in a field-of-view of 25° x 25°. The calibration of the instrument was performed with help of a DOAS instrument that is co-aligned with the SO2 camera. We will present images and SO2 emission rates from both volcanoes. At Lastarria gases are emitted from three different fumarole fields and we will attempt

Lahar hazards at Agua volcano, Guatemala

USGS Publications Warehouse

Schilling, S.P.; Vallance, J.W.; Matías, O.; Howell, M.M.

2001-01-01

At 3760 m, Agua volcano towers more than 3500 m above the Pacific coastal plain to the south and 2000 m above the Guatemalan highlands to the north. The volcano is within 5 to 10 kilometers (km) of Antigua, Guatemala and several other large towns situated on its northern apron. These towns have a combined population of nearly 100,000. It is within about 20 km of Escuintla (population, ca. 100,000) to the south. Though the volcano has not been active in historical time, or about the last 500 years, it has the potential to produce debris flows (watery flows of mud, rock, and debris—also known as lahars when they occur on a volcano) that could inundate these nearby populated areas.

Abrupt shift in δ18O values at Medicine Lake volcano (California, USA)

USGS Publications Warehouse

Donnelly-Nolan, J. M.

1998-01-01

 Oxygen-isotope analyses of lavas from Medicine Lake volcano (MLV), in the southern Cascade Range, indicate a significant change in δ18O in Holocene time. In the Pleistocene, basaltic lavas with <52% SiO2 averaged +5.9‰, intermediate lavas averaged +5.7‰, and silicic lavas (≥63.0%SiO2) averaged +5.6‰. No analyzed Pleistocene rhyolites or dacites have values greater than +6.3‰. In post-glacial time, basalts were similar at +5.7‰ to those erupted in the Pleistocene, but intermediate lavas average +6.8‰ and silicic lavas +7.4‰ with some values as high as +8.5‰. The results indicate a change in the magmatic system supplying the volcano. During the Pleistocene, silicic lavas resulted either from melting of low-18O crust or from fractionation combined with assimilation of very-low-18O crustal material such as hydrothermally altered rocks similar to those found in drill holes under the center of the volcano. By contrast, Holocene silicic lavas were produced by assimilation and/or wholesale melting of high-18O crustal material such as that represented by inclusions of granite in lavas on the upper flanks of MLV. This sudden shift in assimilant indicates a fundamental change in the magmatic system. Magmas are apparently ponding in the crust at a very different level than in Pleistocene time.

Miocene-Pliocene ice-volcano interactions at monogenetic volcanoes near Hobbs Coast, Marie Byrd Land, Antarctica

USGS Publications Warehouse

Wilch, T.I.; McIntosh, W.C.

2007-01-01

Ar geochronology of seven eroded monogenetic volcanoes near the Hobbs Coast, Marie Byrd Land, West Antarctica provide proxy records of WAIS paleo-ice-levels in Miocene-Pliocene times. Interpretations, based on lithofacies analysis, indicate whether the volcanoes erupted below, near, or above the level of the ice sheet. Our interpretations differ significantly from previous interpretations as they highlight the abundant evidence for ice-volcano interactions at emergent paleoenvironments but limited evidence of higher-than-present syn-eruptive ice-levels. Evidence for subglacial volcanic paleoenvironments is limited to Kennel Peak, a ~8 Ma volcano where a pillow lava sequence extending 25 m above current ice level overlies an inferred glacial till and unconformity. A major complication in the Hobbs Coast region is that the volcanism occurred on interfluves between regions of fast-flowing ice. Such a setting precludes establishing precise regional paleo-ice-levels although the presence or absence of ice at times of eruptions can be inferred.

Asymmetric deformation structure of lava spine in Unzen Volcano, Japan

NASA Astrophysics Data System (ADS)

Miwa, T.; Okumura, S.; Matsushima, T.; Shimizu, H.

2013-12-01

Lava spine is commonly generated by effusive eruption of crystal-rich, dacitic-andesitic magmas. Especially, deformation rock on surface of lava spine has been related with processes of magma ascent, outgassing, and generation of volcanic earthquake (e.g., Cashman et al. 2008). To reveal the relationships and generation process of the spine, it is needed to understand a spatial distribution of the deformation rock. Here we show the spatial distribution of the deformation rock of lava spine in the Unzen volcano, Japan, to discuss the generation process of the spine. The lava spine in Unzen volcano is elongated in the E-W direction, showing a crest like shape with 150 long, 40 m wide and 50 m high. The lava spine is divided into following four parts: 1) Massive dacite part: Dense dacite with 30 m of maximum thickness, showing slickenside on the southern face; 2) Sheared dacite part: Flow band developed dacite with 1.0 m of maximum thickness; 3) Tuffisite part: Network of red colored vein develops in dacite with 0.5 m of maximum thickness; 4) Breccia part: Dacitic breccia with 10 m of maximum thickness. The Breccia part dominates in the northern part of the spine, and flops over Massive dacite part accross the Sheared dacite and Tuffisite parts. The slickenside on southern face of massive dacite demonstrates contact of solids. The slickenside breaks both of phenocryst and groundmass, demonstrating that the slickenside is formed after significant crystallization at the shallow conduit or on the ground surface. The lineation of the slickenside shows E-W direction with almost horizontal rake angle, which is consistent with the movement of the spine to an east before emplacement. Development of sub-vertical striation due to extrusion was observed on northern face of the spine (Hayashi, 1994). Therefore, we suggest that the spine just at extrusion consisted of Massive dacite, Sheared dacite, Tuffisite, Breccia, and Striation parts in the northern half of the spine. Such a

Mud volcanoes of the Orinoco Delta, Eastern Venezuela

USGS Publications Warehouse

Aslan, A.; Warne, A.G.; White, W.A.; Guevara, E.H.; Smyth, R.C.; Raney, J.A.; Gibeaut, J.C.

2001-01-01

Mud volcanoes along the northwest margin of the Orinoco Delta are part of a regional belt of soft sediment deformation and diapirism that formed in response to rapid foredeep sedimentation and subsequent tectonic compression along the Caribbean-South American plate boundary. Field studies of five mud volcanoes show that such structures consist of a central mound covered by active and inactive vents. Inactive vents and mud flows are densely vegetated, whereas active vents are sparsely vegetated. Four out of the five mud volcanoes studied are currently active. Orinoco mud flows consist of mud and clayey silt matrix surrounding lithic clasts of varying composition. Preliminary analysis suggests that the mud volcano sediment is derived from underlying Miocene and Pliocene strata. Hydrocarbon seeps are associated with several of the active mud volcanoes. Orinoco mud volcanoes overlie the crest of a mud-diapir-cored anticline located along the axis of the Eastern Venezuelan Basin. Faulting along the flank of the Pedernales mud volcano suggests that fluidized sediment and hydrocarbons migrate to the surface along faults produced by tensional stresses along the crest of the anticline. Orinoco mud volcanoes highlight the proximity of this major delta to an active plate margin and the importance of tectonic influences on its development. Evaluation of the Orinoco Delta mud volcanoes and those elsewhere indicates that these features are important indicators of compressional tectonism along deformation fronts of plate margins. ?? 2001 Elsevier Science B.V. All rights reserved.

Geologic map of Medicine Lake volcano, northern California

USGS Publications Warehouse

Donnelly-Nolan, Julie M.

2011-01-01

Medicine Lake volcano forms a broad, seemingly nondescript highland, as viewed from any angle on the ground. Seen from an airplane, however, treeless lava flows are scattered across the surface of this potentially active volcanic edifice. Lavas of Medicine Lake volcano, which range in composition from basalt through rhyolite, cover more than 2,000 km2 east of the main axis of the Cascade Range in northern California. Across the Cascade Range axis to the west-southwest is Mount Shasta, its towering volcanic neighbor, whose stratocone shape contrasts with the broad shield shape of Medicine Lake volcano. Hidden in the center of Medicine Lake volcano is a 7 km by 12 km summit caldera in which nestles its namesake, Medicine Lake. The flanks of Medicine Lake volcano, which are dotted with cinder cones, slope gently upward to the caldera rim, which reaches an elevation of nearly 8,000 ft (2,440 m). The maximum extent of lavas from this half-million-year-old volcano is about 80 km north-south by 45 km east-west. In postglacial time, 17 eruptions have added approximately 7.5 km3 to its total estimated volume of 600 km3, and it is considered to be the largest by volume among volcanoes of the Cascades arc. The volcano has erupted nine times in the past 5,200 years, a rate more frequent than has been documented at all other Cascades arc volcanoes except Mount St. Helens.

Stratigraphy and Melt Compositions of the 3.6 and 6.7 ka Plinian Eruptions of Hudson Volcano, Chile.

NASA Astrophysics Data System (ADS)

Carey, S.; Scasso, R.; Kratzmann, D.; Naranjo, J.; Bande, A.

2005-12-01

Fallout deposits from two major Holocene eruptions of Hudson Volcano in southern Chile (3.6 ka and 6.7 ka BP, Naranjo and Stern, 1998) provide new evidence for multiple phases, including subplinian to plinian discharges and episodes of phreatomagmatic activity. Four phases have been identified for the 3.6 ka eruption. The melt was trachydacitic and did not exhibit any significant variation throughout the fall sequence. Phase one (P1) produced a commonly reverse graded, lapilli fall deposit. Phase two (P2) also produced a reverse graded, coarse lapilli fall layer. Phase three (P3) deposited a massive, poorly-sorted, silty-ash layer with pumice and minor accretionary lapilli. The final phase of the eruption (P4) laid down a commonly normal graded, coarse lapilli fall deposit. Phases P1, P2 and P4 represent fallout from high altitude plumes with minor intensity fluctuations, whereas P3 resulted from magma/water interactions and a lower eruption column. Isopach maps show a shift in the main dispersal axis for the 3.6 ka phreatomagmatic ashfall (P3), relative to the lapilli deposits. Phases 1, 2 and 4 trend generally to the east, whereas the axis for the P3 fallout trends northeast. This is likely caused by dispersal of material at different altitudes during the eruption and not a general change in the predominant wind direction. Three major phases (P1 to P3) were identified for the 6.7 ka eruption. The initial phase (P1) produced a commonly reverse graded, coarse lapilli fall deposit. The second phase (P2) produced a thick, distinctive accretionary lapilli-rich, silty-ash layer with accretionary lapilli diameters up to 2.3 cm at 35 kms from the volcano. The final phase (P3) laid down an often normal graded, coarse lapilli fall unit. The melt phase was also trachydacitic in composition and relatively uniform during the eruption, but less evolved than the magma erupted during the 3.6 ka event. The accretionary lapilli layer (P2) has been correlated with a widespread

Santa Maria Volcano, Guatemala

NASA Technical Reports Server (NTRS)

2002-01-01

The eruption of Santa Maria volcano in 1902 was one of the largest eruptions of the 20th century, forming a large crater on the mountain's southwest flank. Since 1922, a lava-dome complex, Santiaguito, has been forming in the 1902 crater. Growth of the dome has produced pyroclastic flows as recently as the 2001-they can be identified in this image. The city of Quezaltenango (approximately 90,000 people in 1989) sits below the 3772 m summit. The volcano is considered dangerous because of the possibility of a dome collapse such as one that occurred in 1929, which killed about 5000 people. A second hazard results from the flow of volcanic debris into rivers south of Santiaguito, which can lead to catastrophic flooding and mud flows. More information on this volcano can be found at web sites maintained by the Smithsonian Institution, Volcano World, and Michigan Tech University. ISS004-ESC-7999 was taken 17 February 2002 from the International Space Station using a digital camera. The image is provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Searching and viewing of additional images taken by astronauts and cosmonauts is available at the NASA-JSC Gateway to

Quaternary extrusion rates of the Cascade Range, northwestern United States and southern British Columbia

NASA Astrophysics Data System (ADS)

Sherrod, David R.; Smith, James G.

1990-11-01

Quaternary (2-0 Ma) extrusion rates change significantly along the Cascade Range volcanic arc. The extrusion rate north of Mount Rainier is about 0.21 km3 km-1 m.y.-1; the rate in southern Washington and northern Oregon south to Mount Hood is about 1.6 km3 km-1 m.y.-1; in central Oregon the rate is 3-6 km3 km-1 m.y.-1; and in northern California, the rate is 3.2 km3 km-1 m.y.-1. Eruption style also changes along the arc but at latitudes different from rate changes. At the ends of the arc, volcanism is focused at isolated intermediate to silicic composite volcanoes. The composite volcanoes represent ˜30% of the total volume of the arc. Mafic volcanic fields partly ring some composite volcanoes, especially in the south. In contrast, volcanism is diffused in the middle of the arc, where numerous overlapping mafic shields and a few composite volcanoes have built a broad ridge. Contrasting eruption style may signify diffuse versus focused heat sources or may reflect changes in permeability to ascending magma along the arc.

Erupting Volcano Mount Etna

NASA Technical Reports Server (NTRS)

2002-01-01

Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

Penguin Bank: A Loa-Trend Hawaiian Volcano

NASA Astrophysics Data System (ADS)

Xu, G.; Blichert-Toft, J.; Clague, D. A.; Cousens, B.; Frey, F. A.; Moore, J. G.

2007-12-01

Hawaiian volcanoes along the Hawaiian Ridge from Molokai Island in the northwest to the Big Island in the southeast, define two parallel trends of volcanoes known as the Loa and Kea spatial trends. In general, lavas erupted along these two trends have distinctive geochemical characteristics that have been used to define the spatial distribution of geochemical heterogeneities in the Hawaiian plume (e.g., Abouchami et al., 2005). These geochemical differences are well established for the volcanoes forming the Big Island. The longevity of the Loa- Kea geochemical differences can be assessed by studying East and West Molokai volcanoes and Penguin Bank which form a volcanic ridge perpendicular to the Loa and Kea spatial trends. Previously we showed that East Molokai volcano (~1.5 Ma) is exclusively Kea-like and that West Molokai volcano (~1.8 Ma) includes lavas that are both Loa- and Kea-like (Xu et al., 2005 and 2007).The submarine Penguin Bank (~2.2 Ma), probably an independent volcano constructed west of West Molokai volcano, should be dominantly Loa-like if the systematic Loa and Kea geochemical differences were present at ~2.2 Ma. We have studied 20 samples from Penguin Bank including both submarine and subaerially-erupted lavas recovered by dive and dredging. All lavas are tholeiitic basalt representing shield-stage lavas. Trace element ratios, such as Sr/Nb and Zr/Nb, and isotopic ratios of Sr and Nd clearly are Loa-like. On an ɛNd-ɛHf plot, Penguin Bank lavas fall within the field defined by Mauna Loa lavas. Pb isotopic data lie near the Loa-Kea boundary line defined by Abouchami et al. (2005). In conclusion, we find that from NE to SW, i.e., perpendicular to the Loa and Kea spatial trend, there is a shift from Kea-like East Molokai lavas to Loa-like Penguin Bank lavas with the intermediate West Molokai volcano having lavas with both Loa- and Kea-like geochemical features. Therefore, the Loa and Kea geochemical dichotomy exhibited by Big Island volcanoes

Remote sensing of volcanos and volcanic terrains

NASA Technical Reports Server (NTRS)

Mouginis-Mark, Peter J.; Francis, Peter W.; Wilson, Lionel; Pieri, David C.; Self, Stephen; Rose, William I.; Wood, Charles A.

1989-01-01

The possibility of using remote sensing to monitor potentially dangerous volcanoes is discussed. Thermal studies of active volcanoes are considered along with using weather satellites to track eruption plumes and radar measurements to study lava flow morphology and topography. The planned use of orbiting platforms to study emissions from volcanoes and the rate of change of volcanic landforms is considered.

Eruption of Kliuchevskoi volcano

NASA Image and Video Library

1994-10-05

STS068-155-094 (30 September-11 October 1994) --- (Kliuchevskoi Volcano) The crewmembers used a Linhof large format Earth observation camera to photograph this nadir view of the Kamchatka peninsula's week-old volcano. The eruption and the follow-up environmental activity was photographed from 115 nautical miles above Earth. Six NASA astronauts spent a week and a half aboard the Space Shuttle Endeavour in support of the Space Radar Laboratory 2 (SRL-2) mission.

Bayesian estimation of magma supply, storage, and eruption rates using a multiphysical volcano model: Kīlauea Volcano, 2000-2012

NASA Astrophysics Data System (ADS)

Anderson, Kyle R.; Poland, Michael P.

2016-08-01

Estimating rates of magma supply to the world's volcanoes remains one of the most fundamental aims of volcanology. Yet, supply rates can be difficult to estimate even at well-monitored volcanoes, in part because observations are noisy and are usually considered independently rather than as part of a holistic system. In this work we demonstrate a technique for probabilistically estimating time-variable rates of magma supply to a volcano through probabilistic constraint on storage and eruption rates. This approach utilizes Bayesian joint inversion of diverse datasets using predictions from a multiphysical volcano model, and independent prior information derived from previous geophysical, geochemical, and geological studies. The solution to the inverse problem takes the form of a probability density function which takes into account uncertainties in observations and prior information, and which we sample using a Markov chain Monte Carlo algorithm. Applying the technique to Kīlauea Volcano, we develop a model which relates magma flow rates with deformation of the volcano's surface, sulfur dioxide emission rates, lava flow field volumes, and composition of the volcano's basaltic magma. This model accounts for effects and processes mostly neglected in previous supply rate estimates at Kīlauea, including magma compressibility, loss of sulfur to the hydrothermal system, and potential magma storage in the volcano's deep rift zones. We jointly invert data and prior information to estimate rates of supply, storage, and eruption during three recent quasi-steady-state periods at the volcano. Results shed new light on the time-variability of magma supply to Kīlauea, which we find to have increased by 35-100% between 2001 and 2006 (from 0.11-0.17 to 0.18-0.28 km3/yr), before subsequently decreasing to 0.08-0.12 km3/yr by 2012. Changes in supply rate directly impact hazard at the volcano, and were largely responsible for an increase in eruption rate of 60-150% between 2001 and

Hydrated Sulfates in the Southern High Latitudes of Mars

NASA Astrophysics Data System (ADS)

Ackiss, S. E.; Wray, J. J.

2012-12-01

Sulfates on Mars appear largely concentrated in sedimentary rocks dating to the Late Noachian or Hesperian [e.g., 1], but they are also abundant in Amazonian sand dunes around the north polar cap [2]. The gypsum in those dunes derives from the polar layered deposits [e.g., 3], where it may form when sunlight causes minor melting and weathering of embedded dust. We are investigating whether such processes might have also contributed to sulfate formation elsewhere, specifically in regions surrounding the south polar terrain. Our study regions to date include the Sisyphi Montes (20W-40E and 55-75S) and other mountainous areas near the Thyles Rupes (110-140E and 55-75S), the Ulyxis Rupes (150-180E and 55-70S), and Chamberlin Crater (110-150W and 55-75S). We searched for sulfates using the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). TRR3 images were evaluated using standard CRISM procedures, including the "volcano scan" atmospheric correction. We used spectral parameters to identify regions of interest, from which we extracted spectra, which we divided by spectrally neutral regions in the same scene to remove systematic artifacts. The resulting ratio spectra were visually compared to library spectra to identify possible hydrated mineral constituents. Some sulfates in the southern high latitudes appear localized to mountains of the Sisyphi Montes, which have been interpreted as volcanoes that erupted under a Hesperian ice sheet [4]. These sulfates might have formed via volcanic hydrothermal or acid fog alteration. We found that nearly 50% of the images on putative volcanoes in the Sisyphi Montes show a 1.9 μm absorption consistent with hydration. The percentage for images on the plains between volcanoes is actually higher; i.e., hydration is not unique to the volcanoes. Nevertheless, the three locations at which we found the strongest absorptions are all on volcanoes. In the Thyles Rupes region, 25% of the images on putative volcanoes are hydrated with

Contribution of space platforms to a ground and airborne remote-sensing programme over active Italian volcanoes

NASA Technical Reports Server (NTRS)

Cassinis, R.; Lechi, G. M.; Tonelli, A. M.

1974-01-01

ERTS-1 imagery of the volcanic areas of southern Italy was used primarily for the evaluation of space platform capabilties in the domains of regional geology, soil and rock-type classification and, more generally, to study the environment of active volcanoes. The test sites were selected and equipped primarily to monitor thermal emission, but ground truth data was also collected in other domains (reflectance of rocks, soils and vegetation). The test areas were overflown with a two channel thermal scanner, while a thermo camera was used on the ground to monitor the hot spots. The primary goal of this survey was to plot the changes in thermal emission with time in the framework of a research program for the surveillance of active volcanoes. However, another task was an evaluation of emissivity changes by comparing the outputs of the two thermal channels. These results were compared with the reflectance changes observed on multispectral ERTS-1 imagery.

Spreading and collapse of big basaltic volcanoes

NASA Astrophysics Data System (ADS)

Puglisi, Giuseppe; Bonforte, Alessandro; Guglielmino, Francesco; Peltier, Aline; Poland, Michael

2016-04-01

Among the different types of volcanoes, basaltic ones usually form the most voluminous edifices. Because volcanoes are growing on a pre-existing landscape, the geologic and structural framework of the basement (and earlier volcanic landforms) influences the stress regime, seismicity, and volcanic activity. Conversely, the masses of these volcanoes introduce a morphological anomaly that affects neighboring areas. Growth of a volcano disturbs the tectonic framework of the region, clamps and unclamps existing faults (some of which may be reactivated by the new stress field), and deforms the substratum. A volcano's weight on its basement can trigger edifice spreading and collapse that can affect populated areas even at significant distance. Volcano instability can also be driven by slow tectonic deformation and magmatic intrusion. The manifestations of instability span a range of temporal and spatial scales, ranging from slow creep on individual faults to large earthquakes affecting a broad area. In the frame of MED-SVU project, our work aims to investigate the relation between basement setting and volcanic activity and stability at three Supersite volcanoes: Etna (Sicily, Italy), Kilauea (Island of Hawaii, USA) and Piton de la Fournaise (La Reunion Island, France). These volcanoes host frequent eruptive activity (effusive and explosive) and share common features indicating lateral spreading and collapse, yet they are characterized by different morphologies, dimensions, and tectonic frameworks. For instance, the basaltic ocean island volcanoes of Kilauea and Piton de la Fournaise are near the active ends of long hotspot chains while Mt. Etna has developed at junction along a convergent margin between the African and Eurasian plates and a passive margin separating the oceanic Ionian crust from the African continental crust. Magma supply and plate velocity also differ in the three settings, as to the sizes of the edifices and the extents of their rift zones. These

Sensitivity analysis of earthquake-induced static stress changes on volcanoes: the 2010 Mw 8.8 Chile earthquake

NASA Astrophysics Data System (ADS)

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

2015-06-01

In this work, we analyse in detail how a large earthquake could cause stress changes on volcano plumbing systems and produce possible positive feedbacks in promoting new eruptions. We develop a sensitivity analysis that considers several possible parameters, providing also new constraints on the methodological approach. The work is focus on the Mw 8.8 2010 earthquake that occurred along the Chile subduction zone near 24 historic/Holocene volcanoes, located in the Southern Volcanic Zone. We use six different finite fault-slip models to calculate the static stress change, induced by the coseismic slip, in a direction normal to several theoretical feeder dykes with various orientations. Results indicate different magnitudes of stress change due to the heterogeneity of magma pathway geometry and orientation. In particular, the N-S and NE-SW-striking magma pathways suffer a decrease in stress normal to the feeder dyke (unclamping, up to 0.85 MPa) in comparison to those striking NW-SE and E-W, and in some cases there is even a clamping effect depending on the magma path strike. The diverse fault-slip models have also an effect (up to 0.4 MPa) on the results. As a consequence, we reconstruct the geometry and orientation of the most reliable magma pathways below the 24 volcanoes by studying structural and morphometric data, and we resolve the stress changes on each of them. Results indicate that: (i) volcanoes where post-earthquake eruptions took place experienced earthquake-induced unclamping or very small clamping effects, (ii) several volcanoes that did not erupt yet are more prone to experience future unrest, from the point of view of the host rock stress state, because of earthquake-induced unclamping. Our findings also suggest that pathway orientation plays a more relevant role in inducing stress changes, whereas the depth of calculation (e.g. 2, 5 or 10 km) used in the analysis, is not key a parameter. Earthquake-induced magma-pathway unclamping might contribute to

Multiphase modelling of mud volcanoes

NASA Astrophysics Data System (ADS)

Colucci, Simone; de'Michieli Vitturi, Mattia; Clarke, Amanda B.

2015-04-01

Mud volcanism is a worldwide phenomenon, classically considered as the surface expression of piercement structures rooted in deep-seated over-pressured sediments in compressional tectonic settings. The release of fluids at mud volcanoes during repeated explosive episodes has been documented at numerous sites and the outflows resemble the eruption of basaltic magma. As magma, the material erupted from a mud volcano becomes more fluid and degasses while rising and decompressing. The release of those gases from mud volcanism is estimated to be a significant contributor both to fluid flux from the lithosphere to the hydrosphere, and to the atmospheric budget of some greenhouse gases, particularly methane. For these reasons, we simulated the fluid dynamics of mud volcanoes using a newly-developed compressible multiphase and multidimensional transient solver in the OpenFOAM framework, taking into account the multicomponent nature (CH4, CO2, H2O) of the fluid mixture, the gas exsolution during the ascent and the associated changes in the constitutive properties of the phases. The numerical model has been tested with conditions representative of the LUSI, a mud volcano that has been erupting since May 2006 in the densely populated Sidoarjo regency (East Java, Indonesia), forcing the evacuation of 40,000 people and destroying industry, farmland, and over 10,000 homes. The activity of LUSI mud volcano has been well documented (Vanderkluysen et al., 2014) and here we present a comparison of observed gas fluxes and mud extrusion rates with the outcomes of numerical simulations. Vanderkluysen, L.; Burton, M. R.; Clarke, A. B.; Hartnett, H. E. & Smekens, J.-F. Composition and flux of explosive gas release at LUSI mud volcano (East Java, Indonesia) Geochem. Geophys. Geosyst., Wiley-Blackwell, 2014, 15, 2932-2946

Geomorphometric comparative analysis of Latin-American volcanoes

NASA Astrophysics Data System (ADS)

Camiz, Sergio; Poscolieri, Maurizio; Roverato, Matteo

2017-07-01

The geomorphometric classifications of three groups of volcanoes situated in the Andes Cordillera, Central America, and Mexico are performed and compared. Input data are eight local topographic gradients (i.e. elevation differences) obtained by processing each volcano raster ASTER-GDEM data. The pixels of each volcano DEM have been classified into 17 classes through a K-means clustering procedure following principal component analysis of the gradients. The spatial distribution of the classes, representing homogeneous terrain units, is shown on thematic colour maps, where colours are assigned according to mean slope and aspect class values. The interpretation of the geomorphometric classification of the volcanoes is based on the statistics of both gradients and morphometric parameters (slope, aspect and elevation). The latter were used for a comparison of the volcanoes, performed through classes' slope/aspect scatterplots and multidimensional methods. In this paper, we apply the mentioned methodology on 21 volcanoes, randomly chosen from Mexico to Patagonia, to show how it may contribute to detect geomorphological similarities and differences among them. As such, both its descriptive and graphical abilities may be a useful complement to future volcanological studies.

Efficient inversion of volcano deformation based on finite element models : An application to Kilauea volcano, Hawaii

NASA Astrophysics Data System (ADS)

Charco, María; González, Pablo J.; Galán del Sastre, Pedro

2017-04-01

The Kilauea volcano (Hawaii, USA) is one of the most active volcanoes world-wide and therefore one of the better monitored volcanoes around the world. Its complex system provides a unique opportunity to investigate the dynamics of magma transport and supply. Geodetic techniques, as Interferometric Synthetic Aperture Radar (InSAR) are being extensively used to monitor ground deformation at volcanic areas. The quantitative interpretation of such surface ground deformation measurements using geodetic data requires both, physical modelling to simulate the observed signals and inversion approaches to estimate the magmatic source parameters. Here, we use synthetic aperture radar data from Sentinel-1 radar interferometry satellite mission to image volcano deformation sources during the inflation along Kilauea's Southwest Rift Zone in April-May 2015. We propose a Finite Element Model (FEM) for the calculation of Green functions in a mechanically heterogeneous domain. The key aspect of the methodology lies in applying the reciprocity relationship of the Green functions between the station and the source for efficient numerical inversions. The search for the best-fitting magmatic (point) source(s) is generally conducted for an array of 3-D locations extending below a predefined volume region. However, our approach allows to reduce the total number of Green functions to the number of the observation points by using the, above mentioned, reciprocity relationship. This new methodology is able to accurately represent magmatic processes using physical models capable of simulating volcano deformation in non-uniform material properties distribution domains, which eventually will lead to better description of the status of the volcano.

Klyuchevskaya, Volcano, Kamchatka Peninsula, CIS

NASA Image and Video Library

1991-05-06

STS039-77-010 (28 April 1991) --- The Kamchatka Peninsula, USSR. This oblique view of the eastern margin of the Kamchatka Peninsula shows pack-ice along the coast, which is drifting along with local currents and delineates the circulation patterns. Also visible are the Kamchatka River (left of center), and the volcanic complex with the active volcano Klyuchevskaya (Kloo-chevs'-ska-ya), 15,584 feet in elevation. The last reported eruption of the volcano was on April 8, but an ash and steam plume extending to the south can be seen in this photograph, taken almost three weeks later (April 28). On April 29, the crew observed and photographed the volcano again, and it was no longer visibly active. However, the flanks of the mountain are dirty from the ash fall. Just north of the Kamchatka River (to the left, just off frame) is Shiveluch, a volcano which was active in early April. There are more than 100 volcanic edifices recognized on Kamchatka, with 15 classified as active.

Infrared surveys of Hawaiian volcanoes

USGS Publications Warehouse

Fischer, W. A.; Moxham, R.M.; Polcyn, F.; Landis, G.H.

1964-01-01

Aerial infrared-sensor surveys of Kilauea volcano have depicted the areal extent and the relative intensity of abnormal thermal features in the caldera area of the volcano and along its associated rift zones. Many of these anomalies show correlation with visible steaming and reflect convective transfer of heat to the surface from subterranean sources. Structural details of the volcano, some not evident from surface observation, are also delineated by their thermal abnormalities. Several changes were observed in the patterns of infrared emission during the period of study; two such changes show correlation in location with subsequent eruptions, but the cause-and-effect relationship is uncertain.Thermal anomalies were also observed on the southwest flank of Mauna Loa; images of other volcanoes on the island of Hawaii, and of Haleakala on the island of Maui, revealed no thermal abnormalities.Approximately 25 large springs issuing into the ocean around the periphery of Hawaii have been detected.Infrared emission varies widely with surface texture and composition, suggesting that similar observations may have value for estimating surface conditions on the moon or planets.

Living with Volcanoes: Year Eleven Teaching Resource Unit.

ERIC Educational Resources Information Center

Le Heron, Kiri; Andrews, Jill; Hooks, Stacey; Larnder, Michele; Le Heron, Richard

2000-01-01

Presents a unit on volcanoes and experiences with volcanoes that helps students develop geography skills. Focuses on four volcanoes: (1) Rangitoto Island; (2) Lake Pupuke; (3) Mount Smart; and (4) One Tree Hill. Includes an answer sheet and resources to use with the unit. (CMK)

The critical role of volcano monitoring in risk reduction

USGS Publications Warehouse

Tilling, R.I.

2008-01-01

Data from volcano-monitoring studies constitute the only scientifically valid basis for short-term forecasts of a future eruption, or of possible changes during an ongoing eruption. Thus, in any effective hazards-mitigation program, a basic strategy in reducing volcano risk is the initiation or augmentation of volcano monitoring at historically active volcanoes and also at geologically young, but presently dormant, volcanoes with potential for reactivation. Beginning with the 1980s, substantial progress in volcano-monitoring techniques and networks - ground-based as well space-based - has been achieved. Although some geochemical monitoring techniques (e.g., remote measurement of volcanic gas emissions) are being increasingly applied and show considerable promise, seismic and geodetic methods to date remain the techniques of choice and are the most widely used. Availability of comprehensive volcano-monitoring data was a decisive factor in the successful scientific and governmental responses to the reawakening of Mount St. Helens (Washington, USA) in 1980 and, more recently, to the powerful explosive eruptions at Mount Pinatubo (Luzon, Philippines) in 1991. However, even with the ever-improving state-ofthe-art in volcano monitoring and predictive capability, the Mount St. Helens and Pinatubo case histories unfortunately still represent the exceptions, rather than the rule, in successfully forecasting the most likely outcome of volcano unrest.

Effects of Volcanoes on the Natural Environment

NASA Technical Reports Server (NTRS)

Mouginis-Mark, Peter J.

2005-01-01

The primary focus of this project has been on the development of techniques to study the thermal and gas output of volcanoes, and to explore our options for the collection of vegetation and soil data to enable us to assess the impact of this volcanic activity on the environment. We originally selected several volcanoes that have persistent gas emissions and/or magma production. The investigation took an integrated look at the environmental effects of a volcano. Through their persistent activity, basaltic volcanoes such as Kilauea (Hawaii) and Masaya (Nicaragua) contribute significant amounts of sulfur dioxide and other gases to the lower atmosphere. Although primarily local rather than regional in its impact, the continuous nature of these eruptions means that they can have a major impact on the troposphere for years to decades. Since mid-1986, Kilauea has emitted about 2,000 tonnes of sulfur dioxide per day, while between 1995 and 2000 Masaya has emotted about 1,000 to 1,500 tonnes per day (Duffel1 et al., 2001; Delmelle et al., 2002; Sutton and Elias, 2002). These emissions have a significant effect on the local environment. The volcanic smog ("vog" ) that is produced affects the health of local residents, impacts the local ecology via acid rain deposition and the generation of acidic soils, and is a concern to local air traffic due to reduced visibility. Much of the work that was conducted under this NASA project was focused on the development of field validation techniques of volcano degassing and thermal output that could then be correlated with satellite observations. In this way, we strove to develop methods by which not only our study volcanoes, but also volcanoes in general worldwide (Wright and Flynn, 2004; Wright et al., 2004). Thus volcanoes could be routinely monitored for their effects on the environment. The selected volcanoes were: Kilauea (Hawaii; 19.425 N, 155.292 W); Masaya (Nicaragua; 11.984 N, 86.161 W); and Pods (Costa Rica; 10.2OoN, 84.233 W).

Spreading And Collapse Of Big Basaltic Volcanoes

NASA Astrophysics Data System (ADS)

Puglisi, G.; Bonforte, A.; Guglielmino, F.; Peltier, A.; Poland, M. P.

2015-12-01

Among the different types of volcanoes, basaltic ones usually form the most voluminous edifices. Because volcanoes are growing on a pre-existing landscape, the geologic and structural framework of the basement (and earlier volcanic landforms) influences the stress regime, seismicity, and volcanic activity. Conversely, the masses of these volcanoes introduce a morphological anomaly that affects neighboring areas. Growth of a volcano disturbs the tectonic framework of the region, clamps and unclamps existing faults (some of which may be reactivated by the new stress field), and deforms the substratum. A volcano's weight on its basement can trigger edifice spreading and collapse that can affect populated areas even at significant distance. Volcano instability can also be driven by slow tectonic deformation and magmatic intrusion. The manifestations of instability span a range of temporal and spatial scales, ranging from slow creep on individual faults to large earthquakes affecting a broad area. Our work aims to investigate the relation between basement setting and volcanic activity and stability at Etna (Sicily, Italy), Kilauea (Island of Hawaii, USA) and Piton de la Fournaise (La Reunion Island, France). These volcanoes host frequent eruptive activity (effusive and explosive) and share common features indicating lateral spreading and collapse, yet they are characterized by different morphologies, dimensions, and tectonic frameworks. For instance, the basaltic ocean island volcanoes of Kilauea and Piton de la Fournaise are near the active ends of long hotspot chains while Mt. Etna has developed at junction along a convergent margin between the African and Eurasian plates and a passive margin separating the oceanic Ionian crust from the African continental crust. Magma supply and plate velocity also differ in the three settings, as to the sizes of the edifices and the extents of their rift zones. These volcanoes, due to their similarities and differences, coupled with

Volcano Near Pavonis Mons

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-549, 19 November 2003

The volcanic plains to the east, southeast, and south of the giant Tharsis volcano, Pavonis Mons, are dotted by dozens of small volcanoes. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example located near 2.1oS, 109.1oW. The elongate depression in the lower left (southwest) quarter of the image is the collapsed vent area for this small, unnamed volcano. A slightly sinuous, leveed channel runs from the depression toward the upper right (north-northeast); this is the trace of a collapsed lava tube. The entire scene has been mantled by dust, such that none of the original volcanic rocks are exposed--except minor occurrences on the steepest slopes in the vent area. The scene is 3 km (1.9 mi) wide and illuminated by sunlight from the left/upper left.

The violent Strombolian eruption of 10 ka Pelado shield volcano, Sierra Chichinautzin, Central Mexico

NASA Astrophysics Data System (ADS)

Lorenzo-Merino, A.; Guilbaud, M.-N.; Roberge, J.

2018-03-01

Pelado volcano is a typical example of an andesitic Mexican shield with a summital scoria cone. It erupted ca. 10 ka in the central part of an elevated plateau in what is today the southern part of Mexico City. The volcano forms a roughly circular, 10-km wide lava shield with two summital cones, surrounded by up to 2.7-m thick tephra deposits preserved up to a distance of 3 km beyond the shield. New cartographic, stratigraphic, granulometric, and componentry data indicate that Pelado volcano was the product of a single, continuous eruption marked by three stages. In the early stage, a > 1.5-km long fissure opened and was active with mild explosive activity. Intermediate and late stages were mostly effusive and associated with the formation of a 250-m high lava shield. Nevertheless, during these stages, the emission of lava alternated and/or coexisted with highly explosive events that deposited a widespread tephra blanket. In the intermediate stage, multiple vents were active along the fissure, but activity was centered at the main cone during the late stage. The final activity was purely effusive. The volcano emitted > 0.9 km3 dense-rock equivalent (DRE) of tephra and up to 5.6 km3 DRE of lavas. Pelado shares various features with documented "violent Strombolian" eruptions, including a high fragmentation index, large dispersal area, occurrence of plate tephra, high eruptive column, and simultaneous explosive and effusive activity. Our results suggest that the associated hazards (mostly tephra fallout and emplacement of lava) would seriously affect areas located up to 25 km from the vent for fallout and 5 km from the vent for lava, an important issue for large cities built near or on potentially active zones, such as Mexico City.

The role of dyking and fault control in the rapid onset of eruption at Chaitén Volcano, Chile

USGS Publications Warehouse

Wicks, Charles; De La, Llera; Lara, L.E.; Lowenstern, J.

2011-01-01

Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2 May 2008 at Chaitén Volcano, located in Chile’s southern Andean volcanic zone, rhyolitic magma migrated from more than 5 km depth in less than 4 hours and erupted explosively with only two days of detected precursory seismic activity. The last major rhyolite eruption before that at Chaitén was the largest volcanic eruption in the twentieth century, at Novarupta volcano, Alaska, in 1912. Because of the historically rare and explosive nature of rhyolite eruptions and because of the surprisingly short warning before the eruption of the Chaitén volcano, any information about the workings of the magmatic system at Chaitén, and rhyolitic systems in general, is important from both the scientific and hazard perspectives. Here we present surface deformation data related to the Chaitén eruption based on radar interferometry observations from the Japan Aerospace Exploration Agency (JAXA) DAICHI (ALOS) satellite. The data on this explosive rhyolite eruption indicate that the rapid ascent of rhyolite occurred through dyking and that melt segregation and magma storage were controlled by existing faults.

The role of dyking and fault control in the rapid onset of eruption at Chaitén volcano, Chile.

PubMed

Wicks, Charles; de la Llera, Juan Carlos; Lara, Luis E; Lowenstern, Jacob

2011-10-19

Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2 May 2008 at Chaitén Volcano, located in Chile's southern Andean volcanic zone, rhyolitic magma migrated from more than 5 km depth in less than 4 hours (ref. 1) and erupted explosively with only two days of detected precursory seismic activity. The last major rhyolite eruption before that at Chaitén was the largest volcanic eruption in the twentieth century, at Novarupta volcano, Alaska, in 1912. Because of the historically rare and explosive nature of rhyolite eruptions and because of the surprisingly short warning before the eruption of the Chaitén volcano, any information about the workings of the magmatic system at Chaitén, and rhyolitic systems in general, is important from both the scientific and hazard perspectives. Here we present surface deformation data related to the Chaitén eruption based on radar interferometry observations from the Japan Aerospace Exploration Agency (JAXA) DAICHI (ALOS) satellite. The data on this explosive rhyolite eruption indicate that the rapid ascent of rhyolite occurred through dyking and that melt segregation and magma storage were controlled by existing faults.

Ubinas Volcano Activity in Peruvian Andes

NASA Image and Video Library

2014-05-01

On April 28, 2014, NASA Terra spacecraft spotted signs of activity at Ubinas volcano in the Peruvian Andes. The appearance of a new lava dome in March 2014 and frequent ash emissions are signs of increasing activity at this volcano.

Fumarole/plume and diffuse CO2 emission from Sierra Negra volcano, Galapagos archipelago

NASA Astrophysics Data System (ADS)

Padron, E.; Hernandez Perez, P. A.; Perez, N.; Theofilos, T.; Melian, G.; Barrancos, J.; Virgil, G.; Sumino, H.; Notsu, K.

2009-12-01

The active shield-volcano Sierra Negra is part of the Galapagos hotspot. Sierra Negra is the largest shield volcano of Isabela Island, hosting a 10 km diameter caldera. Ten historic eruptions have occurred and some involved a frequently visited east caldera rim fissure zone called Volcan Chico. The last volcanic event occurred in October 2005 and lasted for about a week, covering approximately twenty percent of the eastern caldera floor. Sierra Negra volcano has experienced some significant changes in the chemical composition of its volcanic gas discharges after the 2005 eruption. This volcanic event produced an important SO2 degassing that depleted the magmatic content of this gas. Not significant changes in the MORB and plume-type helium contribution were observed after the 2005 eruption, with a 65.5 % of MORB and 35.5 % of plume contribution. In 2006 a visible and diffuse gas emission study was performed at the summit of Sierra Negra volcano, Galapagos, to evaluate degassing rate from this volcanic system. Diffuse degassing at Sierra Negra was mainly confined in three different DDS: Volcan Chico, the southern inner margin of the caldera, and Mina Azufral. These areas showed also visible degassing, which indicates highly fractured areas where volcano-hydrothermal fluids migrate towards surface. A total fumarole/plume SO2 emission of 11 ± 2 td-1 was calculated by mini-DOAS ground-based measurements at Mina Azufral fumarolic area. Molar ratios of major volcanic gas components were also measured in-situ at Mina Azufral with a portable multisensor. The results showed H2S/SO2, CO2/SO2 and H2O/SO2 molar ratios of 0.41, 52.2 and 867.9, respectively. Multiplying the observed SO2 emission rate times the observed (gas)i/SO2 mass ratio we have estimated other volatiles emission rates. The results showed that H2O, CO2 and H2S emission rates from Sierra Negra are 562, 394, and 2.4 t d-1, respectively. The estimated total output of diffuse CO2 emission from the summit of

The Mediterranean Supersite Volcanoes (MED-SUV) Project: an overview

NASA Astrophysics Data System (ADS)

Puglisi, Giuseppe

2013-04-01

In response to the EC call ENV.2012.6.4-2 (Long-term monitoring experiments in geologically active regions of Europe prone to natural hazards: the Supersite concept - FP7-ENV-2012-two-stage) a wide community of volcanological institutions proposed the project Mediterranean Supersite Volcanoes (MED-SUV), which is in the negotiation phase at the time of writing. The Consortium is composed by 18 European University and research institutes, four Small or Medium Enterprises (SME) and two non-European University and research institutes. MED-SUV will improve the consortium capacity of assessment of volcanic hazards in Supersites of Southern Italy by optimising and integrating existing and new observation/monitoring systems, by a breakthrough in understanding of volcanic processes and by increasing the effectiveness of the coordination between the scientific and end-user communities. More than 3 million of people are exposed to potential volcanic hazards in a large region in the Mediterranean Sea, where two among the largest European volcanic areas are located: Mt. Etna and Campi Flegrei/Vesuvius. This project will fully exploit the unique detailed long-term in-situ monitoring data sets available for these volcanoes and integrate with Earth Observation (EO) data, setting the basic tools for a significant step ahead in the discrimination of pre-, syn- and post-eruptive phases. The wide range of styles and intensities of volcanic phenomena observed on these volcanoes, which can be assumed as archetypes of 'closed conduit ' and 'open conduit' volcano, together with the long-term multidisciplinary data sets give an exceptional opportunity to improve the understanding of a very wide spectrum of geo-hazards, as well as implementing and testing a large variety of innovative models of ground deformation and motion. Important impacts on the European industrial sector are expected, arising from a partnership integrating the scientific community and SMEs to implement together new

A Probabilistic Approach for Real-Time Volcano Surveillance

NASA Astrophysics Data System (ADS)

Cannavo, F.; Cannata, A.; Cassisi, C.; Di Grazia, G.; Maronno, P.; Montalto, P.; Prestifilippo, M.; Privitera, E.; Gambino, S.; Coltelli, M.

2016-12-01

Continuous evaluation of the state of potentially dangerous volcanos plays a key role for civil protection purposes. Presently, real-time surveillance of most volcanoes worldwide is essentially delegated to one or more human experts in volcanology, who interpret data coming from different kind of monitoring networks. Unfavorably, the coupling of highly non-linear and complex volcanic dynamic processes leads to measurable effects that can show a large variety of different behaviors. Moreover, due to intrinsic uncertainties and possible failures in some recorded data, the volcano state needs to be expressed in probabilistic terms, thus making the fast volcano state assessment sometimes impracticable for the personnel on duty at the control rooms. With the aim of aiding the personnel on duty in volcano surveillance, we present a probabilistic graphical model to estimate automatically the ongoing volcano state from all the available different kind of measurements. The model consists of a Bayesian network able to represent a set of variables and their conditional dependencies via a directed acyclic graph. The model variables are both the measurements and the possible states of the volcano through the time. The model output is an estimation of the probability distribution of the feasible volcano states. We tested the model on the Mt. Etna (Italy) case study by considering a long record of multivariate data from 2011 to 2015 and cross-validated it. Results indicate that the proposed model is effective and of great power for decision making purposes.

Lahar hazards at Mombacho Volcano, Nicaragua

USGS Publications Warehouse

Vallance, J.W.; Schilling, S.P.; Devoli, G.

2001-01-01

Mombacho volcano, at 1,350 meters, is situated on the shores of Lake Nicaragua and about 12 kilometers south of Granada, a city of about 90,000 inhabitants. Many more people live a few kilometers southeast of Granada in 'las Isletas de Granada and the nearby 'Peninsula de Aseses. These areas are formed of deposits of a large debris avalanche (a fast moving avalanche of rock and debris) from Mombacho. Several smaller towns with population, in the range of 5,000 to 12,000 inhabitants are to the northwest and the southwest of Mombacho volcano. Though the volcano has apparently not been active in historical time, or about the last 500 years, it has the potential to produce landslides and debris flows (watery flows of mud, rock, and debris -- also known as lahars when they occur on a volcano) that could inundate these nearby populated areas. -- Vallance, et.al., 2001

Bayesian estimation of magma supply, storage, and eruption rates using a multiphysical volcano model: Kīlauea Volcano, 2000–2012

USGS Publications Warehouse

Anderson, Kyle R.; Poland, Michael

2016-01-01

Estimating rates of magma supply to the world's volcanoes remains one of the most fundamental aims of volcanology. Yet, supply rates can be difficult to estimate even at well-monitored volcanoes, in part because observations are noisy and are usually considered independently rather than as part of a holistic system. In this work we demonstrate a technique for probabilistically estimating time-variable rates of magma supply to a volcano through probabilistic constraint on storage and eruption rates. This approach utilizes Bayesian joint inversion of diverse datasets using predictions from a multiphysical volcano model, and independent prior information derived from previous geophysical, geochemical, and geological studies. The solution to the inverse problem takes the form of a probability density function which takes into account uncertainties in observations and prior information, and which we sample using a Markov chain Monte Carlo algorithm. Applying the technique to Kīlauea Volcano, we develop a model which relates magma flow rates with deformation of the volcano's surface, sulfur dioxide emission rates, lava flow field volumes, and composition of the volcano's basaltic magma. This model accounts for effects and processes mostly neglected in previous supply rate estimates at Kīlauea, including magma compressibility, loss of sulfur to the hydrothermal system, and potential magma storage in the volcano's deep rift zones. We jointly invert data and prior information to estimate rates of supply, storage, and eruption during three recent quasi-steady-state periods at the volcano. Results shed new light on the time-variability of magma supply to Kīlauea, which we find to have increased by 35–100% between 2001 and 2006 (from 0.11–0.17 to 0.18–0.28 km3/yr), before subsequently decreasing to 0.08–0.12 km3/yr by 2012. Changes in supply rate directly impact hazard at the volcano, and were largely responsible for an increase in eruption rate of 60–150% between

Volcano Hazards - A National Threat

USGS Publications Warehouse

,

2006-01-01

When the violent energy of a volcano is unleashed, the results are often catastrophic. The risks to life, property, and infrastructure from volcanoes are escalating as more and more people live, work, play, and travel in volcanic regions. Since 1980, 45 eruptions and 15 cases of notable volcanic unrest have occurred at 33 U.S. volcanoes. Lava flows, debris avalanches, and explosive blasts have invaded communities, swept people to their deaths, choked major riverways, destroyed bridges, and devastated huge tracts of forest. Noxious volcanic gas emissions have caused widespread lung problems. Airborne ash clouds have disrupted the health, lives, and businesses of hundreds of thousands of people; caused millions of dollars of aircraft damage; and nearly brought down passenger flights.

Late Ediacaran volcano-sedimentary successions of southern Sinai (Egypt): tracing the evolution from late- to post-collisional volcanism and its relation to A-type rocks

NASA Astrophysics Data System (ADS)

Azer, Mokhles; Asimow, Paul; Obeid, Mohamed; Price, Jason; Wang, Max

2017-04-01

The Late Ediacaran post-collisional volcano-sedimentary successions exposed in southern Sinai (Egypt) represent the last stage of magmatic activity associated with assembly of the northernmost segment of the Neoproterozoic Arabian-Nubian Shield. To clarify the age and tempo of post-collisional activity, three volcanic successions from southern Sinai were selected for the present study: the Sahiya, Iqna Shar'a and Meknas volcanics. They comprise a series of intermediate to silicic volcanic flows and their pyroclastic rocks. New zircon U-Pb dating by SIMS of the lava flows from the three successions yielded ages ranging between ca. 619 to 600 Ma. Combined with field evidence and the geochemical data, the obtained SIMS zircon ages enable us to recognize two phases of volcanic activity in southern Sinai at ca. 619-615 Ma and 606-600 Ma. Both age groups were found within the more northerly volcanic successions at Iqna Shar'a and Meknas and in both these sequences the younger phase uncomformably overlies the older phase. Only the older ages, ca. 615-619 Ma, were found in the Sahiya volcanics, exposed at the southern tip of Sinai. The ages of the youngest calc-alkaline volcanics in the study areas are similar to or slightly younger than the earliest phases of alkaline volcanism in southern Sinai, indicating coeval extrusion of calc-alkalic and alkalic A-type rocks. This observation corroborates similar observations documenting cogenetic calc-alkalic and alkalic plutons in the surrounding areas in southern Sinai. Geochemically, the volcanic rocks of the three successions display large silica variations and are mostly medium- to high-K calc-alkaline rocks. The first phase, from ca. 619-615 Ma, observed in all three volcanic suites, comprises basaltic andesite, andesite and dacite, whereas the second phase, from ca. 606-600 Ma and observed only in the northern volcanic suites (Iqna Shar'a and Meknas), comprises dacite, rhyodacite and rhyolite. In the Sahiya succession basal

Eruption history of the Tharsis shield volcanoes, Mars

NASA Technical Reports Server (NTRS)

Plescia, J. B.

1993-01-01

The Tharsis Montes volcanoes and Olympus Mons are giant shield volcanoes. Although estimates of their average surface age have been made using crater counts, the length of time required to build the shields has not been considered. Crater counts for the volcanoes indicate the constructs are young; average ages are Amazonian to Hesperian. In relative terms; Arsia Mons is the oldest, Pavonis Mons intermediate, and Ascreaus Mons the youngest of the Tharsis Montes shield; Olympus Mons is the youngest of the group. Depending upon the calibration, absolute ages range from 730 Ma to 3100 Ma for Arsia Mons and 25 Ma to 100 Ma for Olympus Mons. These absolute chronologies are highly model dependent, and indicate only the time surficial volcanism ceased, not the time over which the volcano was built. The problem of estimating the time necessary to build the volcanoes can be attacked in two ways. First, eruption rates from terrestrial and extraterrestrial examples can be used to calculate the required period of time to build the shields. Second, some relation of eruptive activity between the volcanoes can be assumed, such as they all began at a speficic time or they were active sequentially, and calculate the eruptive rate. Volumes of the shield volcanoes were derived from topographic/volume data.

Santorini Volcano

USGS Publications Warehouse

Druitt, T.H.; Edwards, L.; Mellors, R.M.; Pyle, D.M.; Sparks, R.S.J.; Lanphere, M.; Davies, M.; Barreirio, B.

1999-01-01

Santorini is one of the most spectacular caldera volcanoes in the world. It has been the focus of significant scientific and scholastic interest because of the great Bronze Age explosive eruption that buried the Minoan town of Akrotiri. Santorini is still active. It has been dormant since 1950, but there have been several substantial historic eruptions. Because of this potential risk to life, both for the indigenous population and for the large number of tourists who visit it, Santorini has been designated one of five European Laboratory Volcanoes by the European Commission. Santorini has long fascinated geologists, with some important early work on volcanoes being conducted there. Since 1980, research groups at Cambridge University, and later at the University of Bristol and Blaise Pascal University in Clermont-Ferrand, have collected a large amount of data on the stratigraphy, geochemistry, geochronology and petrology of the volcanics. The volcanic field has been remapped at a scale of 1:10 000. A remarkable picture of cyclic volcanic activity and magmatic evolution has emerged from this work. Much of this work has remained unpublished until now. This Memoir synthesizes for the first time all the data from the Cambridge/Bristol/Clermont groups, and integrates published data from other research groups. It provides the latest interpretation of the tectonic and magmatic evolution of Santorini. It is accompanied by the new 1:10 000 full-colour geological map of the island.

How Do Volcanoes Affect Human Life? Integrated Unit.

ERIC Educational Resources Information Center

Dayton, Rebecca; Edwards, Carrie; Sisler, Michelle

This packet contains a unit on teaching about volcanoes. The following question is addressed: How do volcanoes affect human life? The unit covers approximately three weeks of instruction and strives to present volcanoes in an holistic form. The five subject areas of art, language arts, mathematics, science, and social studies are integrated into…

The Powell Volcano Remote Sensing Working Group Overview

NASA Astrophysics Data System (ADS)

Reath, K.; Pritchard, M. E.; Poland, M. P.; Wessels, R. L.; Biggs, J.; Carn, S. A.; Griswold, J. P.; Ogburn, S. E.; Wright, R.; Lundgren, P.; Andrews, B. J.; Wauthier, C.; Lopez, T.; Vaughan, R. G.; Rumpf, M. E.; Webley, P. W.; Loughlin, S.; Meyer, F. J.; Pavolonis, M. J.

2017-12-01

Hazards from volcanic eruptions pose risks to the lives and livelihood of local populations, with potential global impacts to businesses, agriculture, and air travel. The 2015 Global Assessment of Risk report notes that 800 million people are estimated to live within 100 km of 1400 subaerial volcanoes identified as having eruption potential. However, only 55% of these volcanoes have any type of ground-based monitoring. The only methods currently available to monitor these unmonitored volcanoes are space-based systems that provide a global view. However, with the explosion of data techniques and sensors currently available, taking full advantage of these resources can be challenging. The USGS Powell Center Volcano Remote Sensing Working Group is working with many partners to optimize satellite resources for global detection of volcanic unrest and assessment of potential eruption hazards. In this presentation we will describe our efforts to: 1) work with space agencies to target acquisitions from the international constellation of satellites to collect the right types of data at volcanoes with forecasting potential; 2) collaborate with the scientific community to develop databases of remotely acquired observations of volcanic thermal, degassing, and deformation signals to facilitate change detection and assess how these changes are (or are not) related to eruption; and 3) improve usage of satellite observations by end users at volcano observatories that report to their respective governments. Currently, the group has developed time series plots for 48 Latin American volcanoes that incorporate variations in thermal, degassing, and deformation readings over time. These are compared against eruption timing and ground-based data provided by the Smithsonian Institute Global Volcanism Program. Distinct patterns in unrest and eruption are observed at different volcanoes, illustrating the difficulty in developing generalizations, but highlighting the power of remote sensing

Volcano hazards in the San Salvador region, El Salvador

USGS Publications Warehouse

Major, J.J.; Schilling, S.P.; Sofield, D.J.; Escobar, C.D.; Pullinger, C.R.

2001-01-01

San Salvador volcano is one of many volcanoes along the volcanic arc in El Salvador (figure 1). This volcano, having a volume of about 110 cubic kilometers, towers above San Salvador, the country’s capital and largest city. The city has a population of approximately 2 million, and a population density of about 2100 people per square kilometer. The city of San Salvador and other communities have gradually encroached onto the lower flanks of the volcano, increasing the risk that even small events may have serious societal consequences. San Salvador volcano has not erupted for more than 80 years, but it has a long history of repeated, and sometimes violent, eruptions. The volcano is composed of remnants of multiple eruptive centers, and these remnants are commonly referred to by several names. The central part of the volcano, which contains a large circular crater, is known as El Boquerón, and it rises to an altitude of about 1890 meters. El Picacho, the prominent peak of highest elevation (1960 meters altitude) to the northeast of the crater, and El Jabali, the peak to the northwest of the crater, represent remnants of an older, larger edifice. The volcano has erupted several times during the past 70,000 years from vents central to the volcano as well as from smaller vents and fissures on its flanks [1] (numerals in brackets refer to end notes in the report). In addition, several small cinder cones and explosion craters are located within 10 kilometers of the volcano. Since about 1200 A.D., eruptions have occurred almost exclusively along, or a few kilometers beyond, the northwest flank of the volcano, and have consisted primarily of small explosions and emplacement of lava flows. However, San Salvador volcano has erupted violently and explosively in the past, even as recently as 800 years ago. When such eruptions occur again, substantial population and infrastructure will be at risk. Volcanic eruptions are not the only events that present a risk to local

Geoflicks Reviewed--Films about Hawaiian Volcanoes.

ERIC Educational Resources Information Center

Bykerk-Kauffman, Ann

1994-01-01

Reviews 11 films on volcanic eruptions in the United States. Films are given a one- to five-star rating and the film's year, length, source and price are listed. Top films include "Inside Hawaiian Volcanoes" and "Kilauea: Close up of an Active Volcano." (AIM)

The 2011 unrest at Katla volcano: Characterization and interpretation of the tremor sources

NASA Astrophysics Data System (ADS)

Sgattoni, Giulia; Gudmundsson, Ólafur; Einarsson, Páll; Lucchi, Federico; Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Tryggvason, Ari

2017-05-01

A 23-hour tremor burst was recorded on July 8-9th 2011 at the Katla subglacial volcano, one of the most active and hazardous volcanoes in Iceland. This was associated with deepening of cauldrons on the ice cap and a glacial flood that caused damage to infrastructure. Increased earthquake activity within the caldera started a few days before and lasted for months afterwards and new seismic activity started on the southern flank. No visible eruption broke the ice and the question arose as to whether this episode relates to a minor subglacial eruption with the tremor being generated by volcanic processes, or by the flood. The tremor signal consisted of bursts with varying amplitude and duration. We have identified and described three different tremor phases, based on amplitude and frequency features. A tremor phase associated with the flood was recorded only at stations closest to the river that flooded, correlating in time with rising water level observed at gauging stations. Using back-projection of double cross-correlations, two other phases have been located near the active ice cauldrons and are interpreted to be caused by volcanic or hydrothermal processes. The greatly increased seismicity and evidence of rapid melting of the glacier may be explained by a minor sub-glacial eruption. A less plausible interpretation is that the tremor was generated by hydrothermal boiling and/or explosions with no magma involved. This may have been induced by pressure drop triggered by the release of water when the glacial flood started. All interpretations require an increase of heat released by the volcano.

Small-scale volcanoes on Mars: distribution and types

NASA Astrophysics Data System (ADS)

Broz, Petr; Hauber, Ernst

2015-04-01

Volcanoes differ in sizes, as does the amount of magma which ascends to a planetary surface. On Earth, the size of volcanoes is anti-correlated with their frequency, i.e. small volcanoes are much more numerous than large ones. The most common terrestrial volcanoes are scoria cones (volcano size might be expected. Martian small-scale volcanoes were not intensely studied for a long time due to a lack of high-resolution data enabling their proper identification; however their existence and basic characteristics were predicted on theoretical grounds. Streams of new high-resolution images now enable discovering and studying kilometer-size volcanoes with various shapes in unprecedented detail. Several types of small-scale volcanoes in various regions on Mars were recently described. Scoria cones provide a record of magmatic volatile content and have been identified in Tharsis (Ulysses Colles), on flanks of large volcanoes (e.g., Pavonis Mons), in the caldera of Ulysses Patera, in chaotic terrains or other large depressions (Hydraotes Colles, Coprates Chasma) and in the northern lowlands. Tuff rings and tuff cones, formed as a result of water-magma interaction, seem to be relatively rare on Mars and were only tentatively identified in three locations (Nepenthes/Amenthes region, Arena Colles and inside Lederberg crater), and alternative interpretations (mud volcanoes) seem possible. Other relatively rare volcanoes seem to be lava domes, reported only from two regions (Acracida Planitia and Terra Sirenum). On the other hand, small shields and rootless cones (which are not primary volcanic landforms) represent widely spread phenomena recognized in Tharsis and Elysium. Based on these new observations, the distribution of small volcanoes on Mars seems to be much more widespread than anticipated a decade

Volcanostratigraphic Approach for Evaluation of Geothermal Potential in Galunggung Volcano

NASA Astrophysics Data System (ADS)

Ramadhan, Q. S.; Sianipar, J. Y.; Pratopo, A. K.

2016-09-01

he geothermal systems in Indonesia are primarily associated with volcanoes. There are over 100 volcanoes located on Sumatra, Java, and in the eastern part of Indonesia. Volcanostratigraphy is one of the methods that is used in the early stage for the exploration of volcanic geothermal system to identify the characteristics of the volcano. The stratigraphy of Galunggung Volcano is identified based on 1:100.000 scale topographic map of Tasikmalaya sheet, 1:50.000 scale topographic map and also geological map. The schematic flowchart for evaluation of geothermal exploration is used to interpret and evaluate geothermal potential in volcanic regions. Volcanostratigraphy study has been done on Galunggung Volcano and Talaga Bodas Volcano, West Java, Indonesia. Based on the interpretation of topographic map and analysis of the dimension, rock composition, age and stress regime, we conclude that both Galunggung Volcano and Talaga Bodas Volcano have a geothermal resource potential that deserve further investigation.

Lahar Hazards at Concepción volcano, Nicaragua

USGS Publications Warehouse

Vallance, J.W.; Schilling, S.P.; Devoli, G.; Howell, M.M.

2001-01-01

Concepción is one of Nicaragua’s highest and most active volcanoes. The symmetrical cone occupies the northeastern half of a dumbbell shaped island called Isla Ometepa. The dormant volcano, Maderas, occupies the southwest half of the island. A narrow isthmus connects Concepción and Maderas volcanoes. Concepción volcano towers more than 1600 m above Lake Nicaragua and is within 5 to 10 km of several small towns situated on its aprons at or near the shoreline. These towns have a combined population of nearly 5,000. The volcano has frequently produced debris flows (watery flows of mud, rock, and debris—also known as lahars when they occur on a volcano) that could inundate these nearby populated areas. Concepción volcano has erupted more than 25 times in the last 120 years. Its first recorded activity was in AD 1883. Eruptions in the past century, most of which have originated from a small summit crater, comprise moderate explosions, ash that falls out of eruption plumes (called tephra), and occasional lava flows. Near the summit area, there are accumulations of rock that were emplaced hot (pyroclastic deposits), most of which were hot enough to stick together during deposition (a process called welding). These pyroclastic rocks are rather weak, and tend to break apart easily. The loose volcanic rock remobilizes during heavy rain to form lahars. Volcanic explosions have produced blankets of tephra that are distributed downwind, which on Isla Ometepe is mostly to the west. Older deposits at the west end of the island that are up to 1 m thick indicate larger explosive events have happened at Concepción volcano in prehistoric time. Like pyroclastic-flow deposits, loose tephra on the steep slopes of the volcano provides source material that heavy rainstorms and earthquakes can mobilize to trigger debris flow.

Chikurachki Volcano

Atmospheric Science Data Center

2013-04-16

... southeast. The darker areas of the plume typically indicate volcanic ash, while the white portions of the plume indicate entrained water droplets and ice. According to the Kamchatkan Volcanic Eruptions Response Team (KVERT), the temperature of the plume near the volcano ...

Nyiragonga Volcano

NASA Technical Reports Server (NTRS)

2001-01-01

This image of the Nyiragonga volcano eruption in the Congo was acquired on January 28, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

Image: A river of molten rock poured from the Nyiragongo volcano in the Congo on January 18, 2002, a day after it erupted, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. The flow continued into Lake Kivu. The lave flows are depicted in red on the image indicating they are still hot. Two of them flowed south form the volcano's summit and went through the town of Goma. Another flow can be seen at the top of the image, flowing towards the northwest. One of Africa's most notable volcanoes, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 killed 50 to 100 people, and several villages were destroyed. The image covers an area of 21 x 24 km and combines a thermal band in red, and two infrared bands in green and blue.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the

Geology of kilauea volcano

USGS Publications Warehouse

Moore, R.B.; Trusdell, F.A.

1993-01-01

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower cast rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. ?? 1993.

A Broadly-Based Training Program in Volcano Hazards Monitoring at the Center for the Study of Active Volcanoes

NASA Astrophysics Data System (ADS)

Thomas, D. M.; Bevens, D.

2015-12-01

The Center for the Study of Active Volcanoes, in cooperation with the USGS Volcano Hazards Program at HVO and CVO, offers a broadly based volcano hazards training program targeted toward scientists and technicians from developing nations. The program has been offered for 25 years and provides a hands-on introduction to a broad suite of volcano monitoring techniques, rather than detailed training with just one. The course content has evolved over the life of the program as the needs of the trainees have changed: initially emphasizing very basic monitoring techniques (e.g. precise leveling, interpretation of seismic drum records, etc.) but, as the level of sophistication of the trainees has increased, training in more advanced technologies has been added. Currently, topics of primary emphasis have included volcano seismology and seismic networks; acquisition and modeling of geodetic data; methods of analysis and monitoring of gas geochemistry; interpretation of volcanic deposits and landforms; training in LAHARZ, GIS mapping of lahar risks; and response to and management of volcanic crises. The course also provides training on public outreach, based on CSAV's Hawaii-specific hazards outreach programs, and volcano preparedness and interactions with the media during volcanic crises. It is an intensive eight week course with instruction and field activities underway 6 days per week; it is now offered in two locations, Hawaii Island, for six weeks, and the Cascades volcanoes of the Pacific Northwest, for two weeks, to enable trainees to experience field conditions in both basaltic and continental volcanic environments. The survival of the program for more than two decades demonstrates that a need for such training exists and there has been interaction and contribution to the program by the research community, however broader engagement with the latter continues to present challenges. Some of the reasons for this will be discussed.

Growth and degradation of Hawaiian volcanoes: Chapter 3 in Characteristics of Hawaiian volcanoes

USGS Publications Warehouse

Clague, David A.; Sherrod, David R.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

2014-01-01

Large Hawaiian volcanoes can persist as islands through the rapid subsidence by building upward rapidly enough. But in the long run, subsidence, coupled with surface erosion, erases any volcanic remnant above sea level in about 15 m.y. One consequence of subsidence, in concert with eustatic changes in sea level, is the drowning of coral reefs that drape the submarine flanks of the actively subsiding volcanoes. At least six reefs northwest of the Island of Hawai‘i form a stairstep configuration, the oldest being deepest.

Evolution of deep crustal magma structures beneath Mount Baekdu volcano (MBV) intraplate volcano in northeast Asia

NASA Astrophysics Data System (ADS)

Rhie, J.; Kim, S.; Tkalcic, H.; Baag, S. Y.

2017-12-01

Heterogeneous features of magmatic structures beneath intraplate volcanoes are attributed to interactions between the ascending magma and lithospheric structures. Here, we investigate the evolution of crustal magmatic stuructures beneath Mount Baekdu volcano (MBV), which is one of the largest continental intraplate volcanoes in northeast Asia. The result of our seismic imaging shows that the deeper Moho depth ( 40 km) and relatively higher shear wave velocities (>3.8 km/s) at middle-to-lower crustal depths beneath the volcano. In addition, the pattern at the bottom of our model shows that the lithosphere beneath the MBV is shallower (< 100 km) compared to surrounding regions. Togather with previous P-wave velocity models, we interpret the observations as a compositional double layering of mafic underplating and a overlying cooled felsic structure due to fractional crystallization of asthenosphere origin magma. To achieve enhanced vertical and horizontal model coverage, we apply two approaches in this work, including (1) a grid-search based phase velocity measurement using real-coherency of ambient noise data and (2) a transdimensional Bayesian joint inversion using multiple ambient noise dispersion data.

Long-period seismic events with strikingly regular temporal patterns on Katla volcano's south flank (Iceland)

NASA Astrophysics Data System (ADS)

Sgattoni, Giulia; Jeddi, Zeinab; Gudmundsson, Ólafur; Einarsson, Páll; Tryggvason, Ari; Lund, Björn; Lucchi, Federico

2016-09-01

Katla is a threatening volcano in Iceland, partly covered by the Mýrdalsjökull ice cap. The volcano has a large caldera with several active geothermal areas. A peculiar cluster of long-period seismic events started on Katla's south flank in July 2011, during an unrest episode in the caldera that culminated in a glacier outburst. The seismic events were tightly clustered at shallow depth in the Gvendarfell area, 4 km south of the caldera, under a small glacier stream at the southern margin of Mýrdalsjökull. No seismic events were known to have occurred in this area before. The most striking feature of this seismic cluster is its temporal pattern, characterized by regular intervals between repeating seismic events, modulated by a seasonal variation. Remarkable is also the stability of both the time and waveform features over a long time period, around 3.5 years. We have not found any comparable examples in the literature. Both volcanic and glacial processes can produce similar waveforms and therefore have to be considered as potential seismic sources. Discerning between these two causes is critical for monitoring glacier-clad volcanoes and has been controversial at Katla. For this new seismic cluster on the south flank, we regard volcano-related processes as more likely than glacial ones for the following reasons: 1) the seismic activity started during an unrest episode involving sudden melting of the glacier and a jökulhlaup; 2) the glacier stream is small and stagnant; 3) the seismicity remains regular and stable for years; 4) there is no apparent correlation with short-term weather changes, such as rainstorms. We suggest that a small, shallow hydrothermal system was activated on Katla's south flank in 2011, either by a minor magmatic injection or by changes of permeability in a local crack system.

Copahue Volcano: A Modern Terrestrial Analog for the Opportunity Landing Site?

NASA Astrophysics Data System (ADS)

Varekamp, Johan C.

2004-10-01

The Opportunity Rover on Mars encountered an environment that contained grey hematite (specularite) and jarosite, with structures indicative of flowing water. Less firm evidence suggests the presence of gypsum as well, and the environment is overall rich in S, Cl, and Br (NASA news releases, 2004). Such a suite of minerals may form from an iron- and sulfate-rich brine, either through evaporation, cooling or changes in redox conditions (see Hynek et al. [2002] and Christensen et al. [2001], for a discussion of the extent and possible origins of the Mars hematite deposits). On Earth, such an association of minerals is not very common, but is found in alteration zones with fumarolic activity in some volcanic craters. The condensation or dissolution in meteoric waters of S-rich volcanic gases creates acid fluids in the surficial environment that leach rock-forming elements (RFEs) from the surrounding rocks, forming large, bleached areas of mineralizations of hematite, cristobalite, and gypsum, occasionally with zones rich in alunite or jarosite.

Acoustic scattering from mud volcanoes and carbonate mounds.

PubMed

Holland, Charles W; Weber, Thomas C; Etiope, Giuseppe

2006-12-01

Submarine mud volcanoes occur in many parts of the world's oceans and form an aperture for gas and fluidized mud emission from within the earth's crust. Their characteristics are of considerable interest to the geology, geophysics, geochemistry, and underwater acoustics communities. For the latter, mud volcanoes are of interest in part because they pose a potential source of clutter for active sonar. Close-range (single-interaction) scattering measurements from a mud volcano in the Straits of Sicily show scattering 10-15 dB above the background. Three hypotheses were examined concerning the scattering mechanism: (1) gas entrained in sediment at/near mud volcano, (2) gas bubbles and/or particulates (emitted) in the water column, (3) the carbonate bio-construction covering the mud volcano edifice. The experimental evidence, including visual, acoustic, and nonacoustic sensors, rules out the second hypothesis (at least during the observation time) and suggests that, for this particular mud volcano the dominant mechanism is associated with carbonate chimneys on the mud volcano. In terms of scattering levels, target strengths of 4-14 dB were observed from 800 to 3600 Hz for a monostatic geometry with grazing angles of 3-5 degrees. Similar target strengths were measured for vertically bistatic paths with incident and scattered grazing angles of 3-5 degrees and 33-50 degrees, respectively.

Studies of volcanoes of Alaska by satellite radar interferometry

USGS Publications Warehouse

Lu, Z.; Wicks, C.; Dzurisin, D.; Thatcher, W.; Power, J.; ,

2000-01-01

Interferometric synthetic aperture radar (InSAR) has provided a new imaging geodesy technique to measure the deformation of volcanoes at tens-of-meter horizontal resolution with centimeter to subcentimeter vertical precision. The two-dimensional surface deformation data enables the construction of detailed numerical models allowing the study of magmatic and tectonic processes beneath volcanoes. This paper summarizes our recent: InSAR studies over the Alaska-Aleutian volcanoes, which include New Trident, Okmok, Akutan, Augustine, Shishaldin, and Westdahl volcanoes. The first InSAR surface deformation over the Alaska volcanoes was applied to New Trident. Preliminary InSAR study suggested that New Trident volcano experienced several centimeters inflation from 1993 to 1995. Using the InSAR technique, we studied the 1997 eruption of Okmok. We have measured ???1.4 m deflation during the eruption, ???20 cm pre-eruptive inflation during 1992 to 1995, and >10 cm post-eruptive inflation within a year after the eruption, and modeled the deformations using Mogi sources. We imaged the ground surface deformation associated with the 1996 seismic crisis over Akutan volcano. Although seismic swarm did not result in an eruption, we found that the western part of the volcano uplifted ???60 cm while the eastern part of the island subsided. The majority of the complex deformation field at the Akutan volcano was modeled by dike intrusion and Mogi inflation sources. Our InSAR results also indicate that the pyroclastic flows from last the last eruption have been undergoing contraction/subsidence at a rate of about 3 cm per year since 1992. InSAR measured no surface deformation before and during the 1999 eruption of Shishaldin and suggested the eruption may be a type of open system. Finally, we applied satellite radar interferometry to Westdahl volcano which erupted 1991 and has been quiet since. We discovered this volcano had inflated about 15 cm from 1993 to 1998. In summary, satellite

NASA Satellite Images Erupting Russian Volcano

NASA Image and Video Library

2017-08-22

Klyuchevskoi, one of the world's most active volcanoes, is seen poking through above a solid cloud deck, with an ash plume streaming to the west. Located on the Kamchatka Peninsula in far eastern Russia, it is one of many active volcanoes on the Peninsula. Nearby, to the south, the smaller Bezymianny volcano can be seem with a small steam plume coming from its summit. The image was acquired Aug. 20, 2017, covers an area of 12 by 14 miles (19.5 by 22.7 kilometers), and is located at 56.1 degrees north, 160.6 degrees east. https://photojournal.jpl.nasa.gov/catalog/PIA21878

The eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru)

NASA Astrophysics Data System (ADS)

Samaniego, Pablo; Rivera, Marco; Mariño, Jersy; Guillou, Hervé; Liorzou, Céline; Zerathe, Swann; Delgado, Rosmery; Valderrama, Patricio; Scao, Vincent

2016-09-01

We have reconstructed the eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru) on the basis of extensive fieldwork, and a large dataset of geochronological (40K-40Ar, 14C and 3He) and geochemical (major and trace element) data. This volcanic complex is composed of two successive edifices that have experienced discontinuous volcanic activity from Middle Pleistocene to Holocene times. The Ampato compound volcano consists of a basal edifice constructed over at least two cone-building stages dated at 450-400 ka and 230-200 ka. After a period of quiescence, the Ampato Upper edifice was constructed firstly during an effusive stage (80-70 ka), and then by the formation of three successive peaks: the Northern, Southern (40-20 ka) and Central cones (20-10 ka). The Southern peak, which is the biggest, experienced large explosive phases, resulting in deposits such as the Corinta plinian fallout. During the Holocene, eruptive activity migrated to the NE and constructed the mostly effusive Sabancaya edifice. This cone comprised many andesitic and dacitic blocky lava flows and a young terminal cone, mostly composed of pyroclastic material. Most samples from the Ampato-Sabancaya define a broad high-K magmatic trend composed of andesites and dacites with a mineral assemblage of plagioclase, amphibole, biotite, ortho- and clino-pyroxene, and Fe-Ti oxides. A secondary trend also exists, corresponding to rare dacitic explosive eruptions (i.e. Corinta fallout and flow deposits). Both magmatic trends are derived by fractional crystallisation involving an amphibole-rich cumulate with variable amounts of upper crustal assimilation. A marked change in the overall eruptive rate has been identified between Ampato ( 0.1 km3/ka) and Sabancaya (0.6-1.7 km3/ka). This abrupt change demonstrates that eruptive rates have not been homogeneous throughout the volcano's history. Based on tephrochronologic studies, the Late Holocene Sabancaya activity is characterised by strong

Characteristics of Offshore Hawai';i Island Seismicity and Velocity Structure, including Lo';ihi Submarine Volcano

NASA Astrophysics Data System (ADS)

Merz, D. K.; Caplan-Auerbach, J.; Thurber, C. H.

2013-12-01

the regional velocity model (HG50; Klein, 1989) in the shallow lithosphere above 16 km depth. This is likely a result of thick deposits of volcaniclastic sediments and fractured pillow basalts that blanket the southern submarine flank of Mauna Loa, upon which Lo';ihi is currently superimposing (Morgan et al., 2003). A broad, low-velocity anomaly was observed from 20-40 km deep beneath the area of Pahala, and is indicative of the central plume conduit that supplies magma to the active volcanoes. A localized high-velocity body is observed 4-6 km deep beneath Lo';ihi's summit, extending 10 km to the North and South. Oriented approximately parallel to Lo';ihi's active rift zones, this high-velocity body is suggestive of intrusion in the upper crust, similar to Kilauea's high-velocity rift zones.

The First Historical Eruption of Kambalny Volcano in 2017 .

NASA Astrophysics Data System (ADS)

Gordeev, E.

2017-12-01

The first historical eruption at Kambalny volcano began about 21:20 UTC on March 24, 2017 with powerful ash emissions up to 6 km above sea level from the pre-summit crater. According to tephrochronological data, it is assumed that the strong eruptions of the volcano occurred 200 (?) and 600 years ago. KVERT (Kamchatka Volcanic Eruption Response Team) of the Institute of Volcanology and Seismology FEB RAS has been monitoring Kambalny volcano since 2002. KVERT worked closely with AMC Elizovo and Tokyo VAAC during the eruption at Kambalny volcano in 2017. The maximum intensity of ash emissions occurred on 25-26 March: a continuous plume laden with ash particles spread over several thousand kilometers, changing the direction of propagation from the volcano from the south-west to the south and south-east. On 27-29 March, the ash plume extended to the west, on 30 March - to the southeast of the volcano. On March 31 and April 01, the volcano was relatively quiet. The resumption of the volcano activity after two days of rest was expressed in powerful ash emissions up to 7 km above sea level. Gas-steam plumes containing some amount of ash were noted on 02-05 April, and powerful ash emissions up to 7 km above sea level occurred on 09 April. The explosive activity at the volcano ended on 11 April. The area of ash deposits was about 1500 km2, the total area covered by ash falls, for example, on 25 March, was about 650 thousand km2. To monitor and study the Kambalny volcano eruption we mainly used satellite images of medium resolution available in the information system "Monitoring volcanic activity in Kamchatka and Kurile Islands" (VolSatView). This work was supported by the Russian Science Foundation, project No. 16-17-00042.

Three Short Videos by the Yellowstone Volcano Observatory

USGS Publications Warehouse

Wessells, Stephen; Lowenstern, Jake; Venezky, Dina

2009-01-01

This is a collection of videos of unscripted interviews with Jake Lowenstern, who is the Scientist in Charge of the Yellowstone Volcano Observatory (YVO). YVO was created as a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety. These video presentations give insights about many topics of interest about this area. Title: Yes! Yellowstone is a Volcano An unscripted interview, January 2009, 7:00 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic features at Yellowstone: 'How do we know Yellowstone is a volcano?', 'What is a Supervolcano?', 'What is a Caldera?','Why are there geysers at Yellowstone?', and 'What are the other geologic hazards in Yellowstone?' Title: Yellowstone Volcano Observatory An unscripted interview, January 2009, 7:15 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions about the Yellowstone Volcano Observatory: 'What is YVO?', 'How do you monitor volcanic activity at Yellowstone?', 'How are satellites used to study deformation?', 'Do you monitor geysers or any other aspect of the Park?', 'Are earthquakes and ground deformation common at Yellowstone?', 'Why is YVO a relatively small group?', and 'Where can I get more information?' Title: Yellowstone Eruptions An unscripted interview, January 2009, 6.45 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic

Morphological classification and spatial distribution of Philippine volcanoes

NASA Astrophysics Data System (ADS)

Paguican, E. M. R.; Kervyn, M.; Grosse, P.

2016-12-01

The Philippines is an island arc composed of two major blocks: the aseismic Palawan microcontinental block and the Philippine mobile belt. It is bounded by opposing subduction zones, with the left-lateral Philippine Fault running north-south. This setting is ideal for volcano formation and growth, making it one of the best places to study the controls on island arc volcano morphometry and evolution. In this study, we created a database of volcanic edifices and structures identified on the SRTM 30 m digital elevation models (DEM). We computed the morphometry of each edifice using MORVOLC, an IDL code for generating quantitative parameters based on a defined volcano base and DEM. Morphometric results illustrate the large range of sizes and volumes of Philippine volcanoes. Heirarchical classification by principal component analysis distinguishes between large massifs, large cones/sub-cones, small shields/sub-cones, and small cones, based mainly on size (volume, basal width) and steepness (height/basal width ratio, average slopes). Poisson Nearest Neighbor analysis was used to examine the spatial distribution of volcano centroids. Spatial distribution of the different types of volcanoes suggests that large volcanic massifs formed on thickened crust. Although all the volcanic fields and arcs are a response to tectonic activity such as subduction or rifting, only West Luzon, North and South Mindanao, and Eastern Philippines volcanic arcs and Basilan, Macolod, and Maramag volcanic fields present a statistical clustering of volcanic centers. Spatial distribution and preferential alignment of edifices in all volcanic fields confirm that regional structures had some control on their formation. Volcanoes start either as steep cones or as less steep sub-cones and shields. They then grow into large cones, sub-cones and eventually into massifs as eruption focus shifts within the volcano and new eruptive material is deposited on the slopes. Examination of the directions of

Towards Developing Systematics for Using Periodic Studies of the Hydrothermal Manifestations as Effective Tool for Monitoring Largely 'inaccessible' Volcanoes

NASA Astrophysics Data System (ADS)

Alam, M.

2010-12-01

The San José and Tupungatito volcanoes, located near Santiago (Chile), are the potential hazards, given their geological and historical record of explosive eruptions with pyroclastic flows, most recently in 1960 and 1987 respectively (Global Volcanism Program, Smithsonian Institution). What aggravates the potential risk of these very high (>5290m elevation) snow- and ice-covered volcanoes is their location at the source of relatively narrow mountain drainage systems that feed into the Maipo River, flowing through the southern outskirts of Santiago. Sector-collapse and debris-flow, as a result of volcano-ice/snow interaction, can form lahars causing immense destruction to the life and property in the Maipo Valley (Cajón del Maipo). These lahars can cause submergence and burial of vast downstream areas under several meters thick sediment, as in the case of 1980 eruption of Mount St. Helens, USA. In the event of a major eruption, Santiago city will be at peril, with all the drinking water supply installations either destroyed or contaminated to the extent of being abandoned. Besides, ash and tephra will halt the air traffic in the region, particularly in Santiago-Mendoza sector between Chile and Argentina. In a proposed research project (for which funding is awaited from CONICYT, Chile under its Initiation into Research Funding Competition), hydrothermal systems associated with the aforementioned volcanoes will be periodically studied to monitor these volcanoes, in order to develop a Systematics for using the peripheral hydrothermal manifestations, together with nearby surface water bodies, as means for monitoring the activities of the volcano(es). Basic premise of this proposal is to use the relationship between volcanic and hydrothermal activities. Although this association has been observed at many volcanic centers, no attempt has been made to use this relation effectively as a tool for monitoring the volcanoes. Before an eruption or even with increased

Space Radar Image of Colombian Volcano

NASA Technical Reports Server (NTRS)

1999-01-01

This is a radar image of a little known volcano in northern Colombia. The image was acquired on orbit 80 of space shuttle Endeavour on April 14, 1994, by the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR). The volcano near the center of the image is located at 5.6 degrees north latitude, 75.0 degrees west longitude, about 100 kilometers (65 miles) southeast of Medellin, Colombia. The conspicuous dark spot is a lake at the bottom of an approximately 3-kilometer-wide (1.9-mile) volcanic collapse depression or caldera. A cone-shaped peak on the bottom left (northeast rim) of the caldera appears to have been the source for a flow of material into the caldera. This is the northern-most known volcano in South America and because of its youthful appearance, should be considered dormant rather than extinct. The volcano's existence confirms a fracture zone proposed in 1985 as the northern boundary of volcanism in the Andes. The SIR-C/X-SAR image reveals another, older caldera further south in Colombia, along another proposed fracture zone. Although relatively conspicuous, these volcanoes have escaped widespread recognition because of frequent cloud cover that hinders remote sensing imaging in visible wavelengths. Four separate volcanoes in the Northern Andes nations ofColombia and Ecuador have been active during the last 10 years, killing more than 25,000 people, including scientists who were monitoring the volcanic activity. Detection and monitoring of volcanoes from space provides a safe way to investigate volcanism. The recognition of previously unknown volcanoes is important for hazard evaluations because a number of major eruptions this century have occurred at mountains that were not previously recognized as volcanoes. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of

Morphometry of terrestrial shield volcanoes

NASA Astrophysics Data System (ADS)

Grosse, Pablo; Kervyn, Matthieu

2018-03-01

Shield volcanoes are described as low-angle edifices built primarily by the accumulation of successive lava flows. This generic view of shield volcano morphology is based on a limited number of monogenetic shields from Iceland and Mexico, and a small set of large oceanic islands (Hawaii, Galápagos). Here, the morphometry of 158 monogenetic and polygenetic shield volcanoes is analyzed quantitatively from 90-meter resolution SRTM DEMs using the MORVOLC algorithm. An additional set of 24 lava-dominated 'shield-like' volcanoes, considered so far as stratovolcanoes, are documented for comparison. Results show that there is a large variation in shield size (volumes from 0.1 to > 1000 km3), profile shape (height/basal width (H/WB) ratios mostly from 0.01 to 0.1), flank slope gradients (average slopes mostly from 1° to 15°), elongation and summit truncation. Although there is no clear-cut morphometric difference between shield volcanoes and stratovolcanoes, an approximate threshold can be drawn at 12° average slope and 0.10 H/WB ratio. Principal component analysis of the obtained database enables to identify four key morphometric descriptors: size, steepness, plan shape and truncation. Hierarchical cluster analysis of these descriptors results in 12 end-member shield types, with intermediate cases defining a continuum of morphologies. The shield types can be linked in terms of growth stages and shape evolution, related to (1) magma composition and rheology, effusion rate and lava/pyroclast ratio, which will condition edifice steepness; (2) spatial distribution of vents, in turn related to the magmatic feeding system and the tectonic framework, which will control edifice plan shape; and (3) caldera formation, which will condition edifice truncation.

Iridium emissions from Hawaiian volcanoes

NASA Technical Reports Server (NTRS)

Finnegan, D. L.; Zoller, W. H.; Miller, T. M.

1988-01-01

Particle and gas samples were collected at Mauna Loa volcano during and after its eruption in March and April, 1984 and at Kilauea volcano in 1983, 1984, and 1985 during various phases of its ongoing activity. In the last two Kilauea sampling missions, samples were collected during eruptive activity. The samples were collected using a filterpack system consisting of a Teflon particle filter followed by a series of 4 base-treated Whatman filters. The samples were analyzed by INAA for over 40 elements. As previously reported in the literature, Ir was first detected on particle filters at the Mauna Loa Observatory and later from non-erupting high temperature vents at Kilauea. Since that time Ir was found in samples collected at Kilauea and Mauna Loa during fountaining activity as well as after eruptive activity. Enrichment factors for Ir in the volcanic fumes range from 10,000 to 100,000 relative to BHVO. Charcoal impregnated filters following a particle filter were collected to see if a significant amount of the Ir was in the gas phase during sample collection. Iridium was found on charcoal filters collected close to the vent, no Ir was found on the charcoal filters. This indicates that all of the Ir is in particulate form very soon after its release. Ratios of Ir to F and Cl were calculated for the samples from Mauna Loa and Kilauea collected during fountaining activity. The implications for the KT Ir anomaly are still unclear though as Ir was not found at volcanoes other than those at Hawaii. Further investigations are needed at other volcanoes to ascertain if basaltic volcanoes other than hot spots have Ir enrichments in their fumes.

Darwin's triggering mechanism of volcano eruptions

NASA Astrophysics Data System (ADS)

Galiev, Shamil

2010-05-01

Charles Darwin wrote that ‘… the elevation of many hundred square miles of territory near Concepcion is part of the same phenomenon, with that splashing up, if I may so call it, of volcanic matter through the orifices in the Cordillera at the moment of the shock;…' and ‘…a power, I may remark, which acts in paroxysmal upheavals like that of Concepcion, and in great volcanic eruptions,…'. Darwin reports that ‘…several of the great chimneys in the Cordillera of central Chile commenced a fresh period of activity ….' In particular, Darwin reported on four-simultaneous large eruptions from the following volcanoes: Robinson Crusoe, Minchinmavida, Cerro Yanteles and Peteroa (we cite the Darwin's sentences following his The Voyage of the Beagle and researchspace. auckland. ac. nz/handle/2292/4474). Let us consider these eruptions taking into account the volcano shape and the conduit. Three of the volcanoes (Minchinmavida (2404 m), Cerro Yanteles (2050 m), and Peteroa (3603 m)) are stratovolcanos and are formed of symmetrical cones with steep sides. Robinson Crusoe (922 m) is a shield volcano and is formed of a cone with gently sloping sides. They are not very active. We may surmise, that their vents had a sealing plug (vent fill) in 1835. All these volcanoes are conical. These common features are important for Darwin's triggering model, which is discussed below. The vent fill material, usually, has high level of porosity and a very low tensile strength and can easily be fragmented by tension waves. The action of a severe earthquake on the volcano base may be compared with a nuclear blast explosion of the base. It is known, that after a underground nuclear explosion the vertical motion and the surface fractures in a tope of mountains were observed. The same is related to the propagation of waves in conical elements. After the explosive load of the base. the tip may break and fly off at high velocity. Analogous phenomenon may be generated as a result of a

Living on Active Volcanoes - The Island of Hawai'i

USGS Publications Warehouse

Heliker, Christina; Stauffer, Peter H.; Hendley, James W.

1997-01-01

People on the Island of Hawai'i face many hazards that come with living on or near active volcanoes. These include lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As the population of the island grows, the task of reducing the risk from volcano hazards becomes increasingly difficult. To help protect lives and property, U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory closely monitor and study Hawai'i's volcanoes and issue timely warnings of hazardous activity.

Receiver Function Analyses of Uturuncu Volcano, Bolivia and Lastarria/Cordon Del Azufre Volcanoes, Chile

NASA Astrophysics Data System (ADS)

Mcfarlin, H. L.; Christensen, D. H.; Thompson, G.; McNutt, S. R.; Ryan, J. C.; Ward, K. M.; Zandt, G.; West, M. E.

2014-12-01

Uturuncu Volcano and a zone between Lastarria and Cordon del Azufre Volcanoes (also calledLazufre), have seen much attention lately because of significant and rapid inflation of one to twocentimeters per year over large areas. Uturuncu is located near the Bolivian-Chilean border, andLazufre is located near the Chilean-Argentine border. The PLUTONS Project deployed 28broadband seismic stations around Uturuncu Volcano, from April 2009 to Octobor 2012, and alsodeployed 9 stations around Lastarria and Cordon del Azufre volcanoes, from November, 2011 toApril 2013. Teleseismic receiver functions were generated using the time-domain iterativedeconvolution algorithm of Ligorria and Ammon (1999) for each volcanic area. These receiverfunctions were used to better constrain the depths of magma bodies under Uturuncu and Lazufre,as well as the ultra low velocity layer within the Altiplano-Puna Magma Body (APMB). Thelow velocity zone under Uturuncu is shown to have a top around 10 km depth b.s.l and isgenerally around 20 km thick with regional variations. Tomographic inversion shows a well resolved,near vertical, high Vp/Vs anomaly directly beneath Uturuncu that correlates well with adisruption in the receiver function results; which is inferred to be a magmatic intrusion causing alocal thickening of the APMB. Preliminary results at Lazufre show the top of a low velocityzone around 5-10 km b.s.l with a thickness of 15-30 km.

Sulfur volcanoes on Io?

NASA Astrophysics Data System (ADS)

Greeley, R.; Fink, J. H.

1984-07-01

The unusual rheological properties of sulfur are discussed in order to determine the distinctive volcanic flow morphologies which indicate the presence of sulfur volcanoes on the Saturnian satellite Io. An analysis of high resolution Voyager imagery reveals three features which are considered to be possible sulfur volcanoes: Atar Patera, Daedalus Patera, and Kibero Patera. All three features are distinguished by circular-to-oval central masses surrounded by irregular widespread flows. The central zones of the features are interpreted to be domes formed of high temperature sulfur. To confirm the interpretations of the satellite data, molten sulfur was extruded in the laboratory at a temperature of 210 C on a flat surface sloping 0.5 deg to the left. At this temperature, the sulfur formed a viscous domelike mass over the event. As parts of the mass cooled to 170 C the viscosity decreased to a runny stage, forming breakout flows. It is concluded that a case can be made for sulfur volcanoes on Io sufficient to warrant further study, and it is recommended that the upcoming Galileo mission examine these phenomena.

Sulfur volcanoes on Io?

NASA Technical Reports Server (NTRS)

Greeley, R.; Fink, J. H.

1984-01-01

The unusual rheological properties of sulfur are discussed in order to determine the distinctive volcanic flow morphologies which indicate the presence of sulfur volcanoes on the Saturnian satellite Io. An analysis of high resolution Voyager imagery reveals three features which are considered to be possible sulfur volcanoes: Atar Patera, Daedalus Patera, and Kibero Patera. All three features are distinguished by circular-to-oval central masses surrounded by irregular widespread flows. The central zones of the features are interpreted to be domes formed of high temperature sulfur. To confirm the interpretations of the satellite data, molten sulfur was extruded in the laboratory at a temperature of 210 C on a flat surface sloping 0.5 deg to the left. At this temperature, the sulfur formed a viscous domelike mass over the event. As parts of the mass cooled to 170 C the viscosity decreased to a runny stage, forming breakout flows. It is concluded that a case can be made for sulfur volcanoes on Io sufficient to warrant further study, and it is recommended that the upcoming Galileo mission examine these phenomena.

Modeling volcano growth on the Island of Hawaii: deep-water perspectives

USGS Publications Warehouse

Lipman, Peter W.; Calvert, Andrew T.

2013-01-01

Recent ocean-bottom geophysical surveys, dredging, and dives, which complement surface data and scientific drilling at the Island of Hawaii, document that evolutionary stages during volcano growth are more diverse than previously described. Based on combining available composition, isotopic age, and geologically constrained volume data for each of the component volcanoes, this overview provides the first integrated models for overall growth of any Hawaiian island. In contrast to prior morphologic models for volcano evolution (preshield, shield, postshield), growth increasingly can be tracked by age and volume (magma supply), defining waxing alkalic, sustained tholeiitic, and waning alkalic stages. Data and estimates for individual volcanoes are used to model changing magma supply during successive compositional stages, to place limits on volcano life spans, and to interpret composite assembly of the island. Volcano volumes vary by an order of magnitude; peak magma supply also varies sizably among edifices but is challenging to quantify because of uncertainty about volcano life spans. Three alternative models are compared: (1) near-constant volcano propagation, (2) near-equal volcano durations, (3) high peak-tholeiite magma supply. These models define inconsistencies with prior geodynamic models, indicate that composite growth at Hawaii peaked ca. 800–400 ka, and demonstrate a lower current rate. Recent age determinations for Kilauea and Kohala define a volcano propagation rate of 8.6 cm/yr that yields plausible inception ages for other volcanoes of the Kea trend. In contrast, a similar propagation rate for the less-constrained Loa trend would require inception of Loihi Seamount in the future and ages that become implausibly large for the older volcanoes. An alternative rate of 10.6 cm/yr for Loa-trend volcanoes is reasonably consistent with ages and volcano spacing, but younger Loa volcanoes are offset from the Kea trend in age-distance plots. Variable magma flux

The 2013 eruption of Pavlof Volcano, Alaska: a spatter eruption at an ice- and snow-clad volcano

USGS Publications Warehouse

Waythomas, Christopher F.; Haney, Matthew M.; Fee, David; Schneider, David J.; Wech, Aaron G.

2014-01-01

The 2013 eruption of Pavlof Volcano, Alaska began on 13 May and ended 49 days later on 1 July. The eruption was characterized by persistent lava fountaining from a vent just north of the summit, intermittent strombolian explosions, and ash, gas, and aerosol plumes that reached as high as 8 km above sea level and on several occasions extended as much as 500 km downwind of the volcano. During the first several days of the eruption, accumulations of spatter near the vent periodically collapsed to form small pyroclastic avalanches that eroded and melted snow and ice to form lahars on the lower north flank of the volcano. Continued lava fountaining led to the production of agglutinate lava flows that extended to the base of the volcano, about 3–4 km beyond the vent. The generation of fountain-fed lava flows was a dominant process during the 2013 eruption; however, episodic collapse of spatter accumulations and formation of hot spatter-rich granular avalanches was a more efficient process for melting snow and ice and initiating lahars. The lahars and ash plumes generated during the eruption did not pose any serious hazards for the area. However, numerous local airline flights were cancelled or rerouted, and trace amounts of ash fall occurred at all of the local communities surrounding the volcano, including Cold Bay, Nelson Lagoon, Sand Point, and King Cove.

Eruptions of Hawaiian volcanoes - Past, present, and future

USGS Publications Warehouse

Tilling, Robert I.; Heliker, Christina; Swanson, Donald A.

2010-01-01

Viewing an erupting volcano is a memorable experience, one that has inspired fear, superstition, worship, curiosity, and fascination since before the dawn of civilization. In modern times, volcanic phenomena have attracted intense scientific interest, because they provide the key to understanding processes that have created and shaped more than 80 percent of the Earth's surface. The active Hawaiian volcanoes have received special attention worldwide because of their frequent spectacular eruptions, which often can be viewed and studied with relative ease and safety. In January 1987, the Hawaiian Volcano Observatory (HVO), located on the rim of Kilauea Volcano, celebrated its 75th Anniversary. In honor of HVO's Diamond Jubilee, the U.S. Geological Survey (USGS) published Professional Paper 1350 (see list of Selected Readings, page 57), a comprehensive summary of the many studies on Hawaiian volcanism by USGS and other scientists through the mid-1980s. Drawing from the wealth of data contained in that volume, the USGS also published in 1987 the original edition of this general-interest booklet, focusing on selected aspects of the eruptive history, style, and products of two of Hawai'i's active volcanoes, Kilauea and Mauna Loa. This revised edition of the booklet-spurred by the approaching Centennial of HVO in January 2012-summarizes new information gained since the January 1983 onset of Kilauea's Pu'u 'O'o-Kupaianaha eruption, which has continued essentially nonstop through 2010 and shows no signs of letup. It also includes description of Kilauea's summit activity within Halema'uma'u Crater, which began in mid-March 2008 and continues as of this writing (late 2010). This general-interest booklet is a companion to the one on Mount St. Helens Volcano first published in 1984 and revised in 1990 (see Selected Readings). Together, these publications illustrate the contrast between the two main types of volcanoes: shield volcanoes, such as those in Hawai'i, which generally

First data on the volatile fluxes from passively degassing volcanoes of the Kuril Island arc

NASA Astrophysics Data System (ADS)

Melnikov, Dmitry; Malik, Nataliya; Chaplygin, Ilya; Zelenski, Mikhail

2017-04-01

We report the first data on the volatile fluxes from passively degassing volcanoes of Kuril Island arc in the North-Western Pacific measured in 2015-2016. Four volcanoes: Ebeko on the northern Paramushir Island, Kuntomintar and Pallace on the Central Shiashkotan and Ketoy islands, and Kudryavy on the southern Iturup island are representative for the whole Kuril arc as having the largest and strongest fumarolic fields among 40 of the active volcanoes of the arc. The fluxes were measured using scanning DOAS, remote miniDOAS, plume MultiGas and direct sampling techniques using the SO2 flux from the DOAS data and ratios measured by MultiGas (SO2/CO2, SO2/H2S, SO2/H2O) and direct sampling (SO2/HCl). For Kudryavy volcano the ratios were applied that have been measured by Taran et al. (1995) and Fischer et al. (1998) using direct sampling. Until now, for Kuril arc only the SO2 flux from Kudryavy was measured by the COSPEC technique in 1995 by Fischer et al. (1998) with an average SO2 flux of 75 t/d. Our data give for Kudryavy in October 2016 a value of 340 t/d. The total measured SO2 flux in 2015-2016 from the passively degassing volcanoes of the Kuril arc is near 1000 t/d. This value is an excellent agreement with the estimation made in Taran (2009) using a comparative plume height technique based on visual observations. Averaged fluxes (in ton/day) of mayor (Range of vent temperatures °C, SO2, CO2, H2O, HCl, total flux) components of volcanic emissions from Kurilian volcanoes in 2016: Ebeko - 97-490 °C, 100 (SO2), 81 (CO2), 1120 (H2O), 17 (HCl), 1319; Kuntomintar - 130-260 °C, 54 (SO2), 157 (CO2), 1064 (H2O), 8 (HCl), 1283; Pallas - 140-720 °C, 450 (SO2), 78 (CO2), 3800 (H2O), 120 (HCl), 4448; Kudryavy - 130-920 °C, 340 (SO2), 131 (CO2), 4445 (H2O), 85 (HCl), 5001. Total (± 20%): 930 (SO2), 450 (CO2), 10400 (H2O), 230 (HCl), 12050 (total flux). This work was supported by grant from the Russian Science Foundation # 15-17-20011. References: Taran et al. (1995) GCA

Volcanoes muon imaging using Cherenkov telescopes

NASA Astrophysics Data System (ADS)

Catalano, O.; Del Santo, M.; Mineo, T.; Cusumano, G.; Maccarone, M. C.; Pareschi, G.

2016-01-01

A detailed understanding of a volcano inner structure is one of the key-points for the volcanic hazards evaluation. To this aim, in the last decade, geophysical radiography techniques using cosmic muon particles have been proposed. By measuring the differential attenuation of the muon flux as a function of the amount of rock crossed along different directions, it is possible to determine the density distribution of the interior of a volcano. Up to now, a number of experiments have been based on the detection of the muon tracks crossing hodoscopes, made up of scintillators or nuclear emulsion planes. Using telescopes based on the atmospheric Cherenkov imaging technique, we propose a new approach to study the interior of volcanoes detecting of the Cherenkov light produced by relativistic cosmic-ray muons that survive after crossing the volcano. The Cherenkov light produced along the muon path is imaged as a typical annular pattern containing all the essential information to reconstruct particle direction and energy. Our new approach offers the advantage of a negligible background and an improved spatial resolution. To test the feasibility of our new method, we have carried out simulations with a toy-model based on the geometrical parameters of ASTRI SST-2M, i.e. the imaging atmospheric Cherenkov telescope currently under installation onto the Etna volcano. Comparing the results of our simulations with previous experiments based on particle detectors, we gain at least a factor of 10 in sensitivity. The result of this study shows that we resolve an empty cylinder with a radius of about 100 m located inside a volcano in less than 4 days, which implies a limit on the magma velocity of 5 m/h.

NASA Spacecraft Captures Fury of Russian Volcano

NASA Image and Video Library

2011-01-27

This nighttime thermal infrared image from NASA Terra spacecraft shows Shiveluch volcano, one of the largest and most active volcanoes in Russia Kamchatka Peninsula; the bright, hot summit lava dome is evident in the center of the image.

Eruption of Alaska volcano breaks historic pattern

USGS Publications Warehouse

Larsen, Jessica; Neal, Christina A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick L.

2009-01-01

In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

Eruption of Alaska Volcano Breaks Historic Pattern

NASA Astrophysics Data System (ADS)

Larsen, Jessica; Neal, Christina; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick

2009-05-01

In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (˜2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud “thunder,” lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

Geology of Kilauea volcano

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, R.B.; Trusdell, F.A.

1993-08-01

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailedmore » geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.« less

An Overview of the Southern Mariana Subduction Factory: Arc, Cross-Chains, and Back-Arc Basin

NASA Astrophysics Data System (ADS)

Stern, R. J.; Hargrove, U. S.; Leybourne, M. I.; Pearce, J. A.; Bloomer, S. H.

2002-12-01

The Mariana arc system south of 18°N provides 3 opportunities to study the magmatic outputs of the IBM Subduction Factory: 1) Along the Magmatic arc; 2) Across arc cross-chains; and 3) Along the back-arc basin spreading axis. In spite of being located near population centers of Guam and Saipan, this is a relatively poorly known part of the arc system. There is a clear break in the trend and morphology of the magmatic arc west of the144°E fault and slab tear, and we surveyed and sampled the region north and east of this during the Cook 7 expedition in March-April 2001. Systematic morphologic covariations are observed along the arc and backarc basin magmatic systems, with the shallower ridge depths adjacent to more magmatically-robust arc segments. Our preliminary results reveal a compositional discontinuity in back-arc basin basalts (BABB) south of a bathymetric break near 15°30'N, with BABB in shallower segments to the north having a strong subduction component (higher Ba/Nb, Rb, Zr, etc.) and deeper regions to the south being more MORB-like. This is close to the morphological break along the magmatic front, with larger (>10E11 m3) edifices of the Central Island Province north of 16°N and smaller, entirely submarine volcanoes to the south, implying a more robust magmatic budget in the north; a similar variations are observed for cross-chain volcanoes, with smaller ones associated with the smaller, southern arc volcanoes and larger ones associated with the larger arc volcanoes of the Central Island Province. In contrast to the back-arc basin spreading axis, no systematic compositional variations are observed along or across the arc. Arc and cross-chains comprise a coherent, low- to medium-K, dominantly tholeiitic suite. REE patterns show moderate LREE-enrichment, with chondrite-normalized La/Yb = 1.5-2. Rear-arc volcanoes sometimes are slightly less fractionated, slightly more potassic, and slightly more LREE-enriched, but these are second order differences. The

Iceland: Grímsvötn Volcano

Atmospheric Science Data Center

2013-04-17

article title:  Grímsvötn Volcano Injects Ash into the Stratosphere     ... p.m. local time (1730 UTC) on Saturday, May 21, 2011. The volcano, located approximately 140 miles (220 kilometers) east of the capital ...

The Anatahan volcano-monitoring system

NASA Astrophysics Data System (ADS)

Marso, J. N.; Lockhart, A. B.; White, R. A.; Koyanagi, S. K.; Trusdell, F. A.; Camacho, J. T.; Chong, R.

2003-12-01

A real-time 24/7 Anatahan volcano-monitoring and eruption detection system is now operational. There had been no real-time seismic monitoring on Anatahan during the May 10, 2003 eruption because the single telemetered seismic station on Anatahan Island had failed. On May 25, staff from the Emergency Management Office (EMO) of the Commonwealth of the Northern Mariana Islands and the U. S. Geological Survey (USGS) established a replacement telemetered seismic station on Anatahan whose data were recorded on a drum recorder at the EMO on Saipan, 130 km to the south by June 5. In late June EMO and USGS staff installed a Glowworm seismic data acquisition system (Marso et al, 2003) at EMO and hardened the Anatahan telemetry links. The Glowworm system collects the telemetered seismic data from Anatahan and Saipan, places graphical display products on a webpage, and exports the seismic waveform data in real time to Glowworm systems at Hawaii Volcano Observatory and Cascades Volcano Observatory (CVO). In early July, a back-up telemetered seismic station was placed on Sarigan Island 40 km north of Anatahan, transmitting directly to the EMO on Saipan. Because there is currently no population on the island, at this time the principal hazard presented by Anatahan volcano would be air traffic disruption caused by possible erupted ash. The aircraft/ash hazard requires a monitoring program that focuses on eruption detection. The USGS currently provides 24/7 monitoring of Anatahan with a rotational seismic duty officer who carries a Pocket PC-cell phone combination that receives SMS text messages from the CVO Glowworm system when it detects large seismic signals. Upon receiving an SMS text message notification from the CVO Glowworm, the seismic duty officer can use the Pocket PC - cell phone to view a graphic of the seismic traces on the EMO Glowworm's webpage to determine if the seismic signal is eruption related. There have been no further eruptions since the monitoring system was

Petrology of deep drill hole, Kilauea Volcano

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grose, L.T.; Keller, G.V.

1976-12-01

The first deep drill hole (1262 m TD) at the summit of an active volcano (1102 m elev) was drilled in 1973 at Kilauea volcano, Hawaii with support from NSF and USGS. The hole is located within southern margin of Kilauea caldera in northern part of a 15 km/sup 2/ triangular block bounded by east rift zone, Koae fault zone, and southwest rift zone-a summit area relatively free of faults, rifts, and extrusions. Nearest eruptions are from fissures 1.2 km away which are active in 1974 and which do not trend toward the drill hole. Core recovery totals 47 mmore » from 29 core runs at rather evenly spaced intervals to total depth. Megascopic, thin-section, and X-ray examination reveals: (1) Recovered core is essentially vesicular, intergranular, nonporphyritic to porphyritic olivine basalt with minor olivine diabase, picrite diabase, and basalt, (2) Hyaloclastite and pillow basalt are absent, (3) Below water table (614 m elev) with increasing depth, vesicularity decreases, and density, crystallinity, competence, vesicle fill, and alteration irregularly increase, (4) Alteration first occurs at water table where calcite and silica partially fill vesticles and olivine is partially serpentinized, (5) At about 570 m elev massive serpentinization of olivine and deposition of montmorillonite-nontronite occur; at about 210 m elev truscottite and tobermorite occur in vesicles; at about 35 m elev mordenite occurs in vesicles, (6) Bottom-hole cores have complete filling of vesicles with silica, minor silica replacement, and complete alteration of olivine, and (7) Plagioclase is unaltered. Chemical analyses of bottom-hole cores are similar to those of modern summit lavas. Alteration and low porosity in bottom-hole cores plus abrupt temperature increase suggest the drill hole penetrated a self-sealed ''cap rock'' to a hydrothermal convection cell and possibly a magma body.« less

Seismic attenuation structure beneath Nazca Plate subduction zone in southern Peru

NASA Astrophysics Data System (ADS)

Jang, H.; Kim, Y.; Clayton, R. W.

2017-12-01

We estimate seismic attenuation in terms of quality factors, QP and QS using P and S phases, respectively, beneath Nazca Plate subduction zone between 10°S and 18.5°S latitude in southern Peru. We first relocate 298 earthquakes with magnitude ranges of 4.0-6.5 and depth ranges of 20-280 km. We measure t*, which is an integrated attenuation through the seismic raypath between the regional earthquakes and stations. The measured t* are inverted to construct three-dimensional attenuation structures of southern Peru. Checkerboard test results for both QP and QS structures ensure good resolution in the slab-dip transition zone between flat and normal slab subduction down to a depth of 200 km. Both QP and QS results show higher attenuation continued down to a depth of 50 km beneath volcanic arc and also beneath the Quimsachata volcano, the northernmost young volcano, located far east of the main volcanic front. We also observe high attenuation in mantle wedge especially beneath the normal subduction region in both QP and QS (100-130 in QP and 100-125 in QS) and slightly higher QP and QS beneath the flat-subduction and slab-dip transition regions. We plan to relate measured attenuation in the mantle wedge to material properties such as viscosity to understand the subduction zone dynamics.

Hawaii Volcano Observatory 75th anniversary

USGS Publications Warehouse

Wright, Thomas L.; Decker, Robert W.

1988-01-01

The 75th anniversary of the founding of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) was celebrated in January 1987. The festivities began on January 9 with the opening in Hilo of a major exhibit at the Wailoa Center on the current work of HVO, its history, and its special relationship to Hawaii Volcanoes National Park.

Iceland's Grímsvötn volcano erupts

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-05-01

About 13 months after Iceland's Eyjafjallajökull volcano began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn volcano in southeastern took its turn. Iceland's most active volcano, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the volcano was beginning to subside.

Active Deformation of Etna Volcano Combing IFSAR and GPS data

NASA Technical Reports Server (NTRS)

Lundgren, Paul

1997-01-01

The surface deformation of an active volcano is an important indicator of its eruptive state and its hazard potential. Mount Etna volcano in Sicily is a very active volcano with well documented eruption episodes.

Muon imaging of volcanoes with Cherenkov telescopes

NASA Astrophysics Data System (ADS)

Carbone, Daniele; Catalano, Osvaldo; Cusumano, Giancarlo; Del Santo, Melania; La Parola, Valentina; La Rosa, Giovanni; Maccarone, Maria Concetta; Mineo, Teresa; Pareschi, Giovanni; Sottile, Giuseppe; Zuccarello, Luciano

2017-04-01

La Nave (southern flank of Mt. Etna, Italy; 1740m a.s.l.), in the framework of ASTRI, a flagship project of the Italian Ministry of Education, University and Research, led by the Italian National Institute of Astrophysics (INAF). This offers the opportunity to test the use of a Cherenkov telescope for imaging volcanic structures. Starting from this know-how, we plan to develop a new prototype of Cherenkov detector with suitable characteristics for installation in the summit zone of Etna volcano (around 3000m a.s.l.).

Diffuse He degassing from Cumbre Vieja volcano, La Palma, Canary Islands

NASA Astrophysics Data System (ADS)

Asensio-Ramos, María; De Jongh, Marli E.; Lamfers, Kristen R.; Alonso, Mar; Amonte, Cecilia; Padrón, Eleazar; Hernández, Pedro A.; Pérez, Nemesio M.

2017-04-01

Helium is considered as an ideal geochemical tracer due to its geochemical properties: chemical inertness, physical stability and practical insolubility in water under normal conditions. These characteristics, together with its high mobility on the crust, make the presence of helium anomalies on the surface environment of a volcanic system to be related to deep fluid migration controlled by volcano-tectonic features, also providing valuable information about the location and characteristics of the gas source and the fracturing of the crust. The recent results reported by Padrón et al. (2013) clearly show importance of helium emission studies for the prediction of major volcanic events and the importance of continuous monitoring of this gas in active volcanic regions. La Palma Island (708.32 km2) is located at the northwestern end of the Canarian Archipelago. Subaerial volcanic activity on this island started ˜2.0 My ago and has taken place exclusively at the southern part in the last 123 ka. Cumbre Vieja volcano, the most active basaltic volcano of the Canary Islands, was built in this zone, including a main north-south rift area 20 km long and up to 1,950 m in elevation, with vents located also at the northwest and northeast. Padrón et al., (2012) showed that helium is mainly emitted along both N-S and N-W rift of Cumbre Vieja, being, therefore, zones of enhanced permeability for deep gas migration and preferential routes for degassing. This work represents a continuation of the results obtained by Padrón et al. (2012) until the year 2016. Each study covered the 220 km2 of Cumbre Vieja with an average of 570 homogenously distributed sampling points. At each sampling site, soil gas samples were collected at 40 cm depth by withdrawing the gas aliquots into 60 cc hypodermic syringes. He content in the soil gases was analyzed by means of quadrupole mass spectrometry (QMS). Atmospheric gas was used periodically to calibrate the instrument. To estimate the helium

July 1973 ground survey of active Central American volcanoes

NASA Technical Reports Server (NTRS)

Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

1973-01-01

The author has identified the following significant results. Ground survey has shown that thermal anomalies of various sizes associated with volcanic activity at several Central American volcanoes should be detectable from Skylab. Anomalously hot areas of especially large size (greater than 500 m in diameter) are now found at Santiaguito and Pacaya volcanoes in Guatemala and San Cristobal in Nicaragua. Smaller anomalous areas are to be found at least seven other volcanoes. This report is completed after ground survey of eleven volcanoes and ground-based radiation thermometry mapping at these same points.

The Ninole Basalt - Implications for the structural evolution of Mauna Loa volcano, Hawaii

USGS Publications Warehouse

Lipman, P.W.; Rhodes, J.M.; Dalrymple, G.B.

1990-01-01

Lava flows of the Ninole Basalt, the oldest rocks exposed on the south side of the island of Hawaii, provide age and compositional constraints on the evolution of Mauna Loa volcano and the southeastward age progression of Hawaiian volcanism. Although the tholeiitic Ninole Basalt differs from historic lavas of Mauna Loa volcano in most major-element contents (e.g., variably lower K, Na, Si; higher Al, Fe, Ti, Ca), REE and other relatively immobile minor elements are similar to historic and prehistoric Mauna Loa lavas, and the present major-element differences are mainly due to incipient weathering in the tropical environment. New K-Ar whole-rock ages, from relatively fresh roadcut samples, suggest that the age of the Ninole Basalt is approximately 0.1-0.2 Ma, although resolution is poor because of low contents of K and radiogenic Ar. Originally considered the remnants of a separate volcano, the Ninole Hills are here interpreted as faulted remnants of the old south flank of Mauna Loa. Deep canyons in the Ninole Hills, eroded after massive landslide failure of flanks of the southwest rift zone, have been preserved from burial by younger lava due to westward migration of the rift zone. Landslide-induced depressurization of the southwest rift zone may also have induced phreatomagmatic eruptions that could have deposited widespread Basaltic ash that overlies the Ninole Basalt. Subaerial presence of the Ninole Basalt documents that the southern part of Hawaii Island had grown to much of its present size above sea level by 0.1-0.2 Ma, and places significant limits on subsequent enlargement of the south flank of Mauna Loa. ?? 1990 Springer-Verlag.

Venus small volcano classification and description

NASA Technical Reports Server (NTRS)

Aubele, J. C.

1993-01-01

The high resolution and global coverage of the Magellan radar image data set allows detailed study of the smallest volcanoes on the planet. A modified classification scheme for volcanoes less than 20 km in diameter is shown and described. It is based on observations of all members of the 556 significant clusters or fields of small volcanoes located and described by this author during data collection for the Magellan Volcanic and Magmatic Feature Catalog. This global study of approximately 10 exp 4 volcanoes provides new information for refining small volcano classification based on individual characteristics. Total number of these volcanoes was estimated to be 10 exp 5 to 10 exp 6 planetwide based on pre-Magellan analysis of Venera 15/16, and during preparation of the global catalog, small volcanoes were identified individually or in clusters in every C1-MIDR mosaic of the Magellan data set. Basal diameter (based on 1000 measured edifices) generally ranges from 2 to 12 km with a mode of 34 km, and follows an exponential distribution similar to the size frequency distribution of seamounts as measured from GLORIA sonar images. This is a typical distribution for most size-limited natural phenomena unlike impact craters which follow a power law distribution and continue to infinitely increase in number with decreasing size. Using an exponential distribution calculated from measured small volcanoes selected globally at random, we can calculate total number possible given a minimum size. The paucity of edifice diameters less than 2 km may be due to inability to identify very small volcanic edifices in this data set; however, summit pits are recognizable at smaller diameters, and 2 km may represent a significant minimum diameter related to style of volcanic eruption. Guest, et al, discussed four general types of small volcanic edifices on Venus: (1) small lava shields; (2) small volcanic cones; (3) small volcanic domes; and (4) scalloped margin domes ('ticks'). Steep

Mount Rainier: A decade volcano

NASA Astrophysics Data System (ADS)

Swanson, Donald A.; Malone, Stephen D.; Samora, Barbara A.

Mount Rainier, the highest (4392 m) volcano in the Cascade Range, towers over a population of more than 2.5 million in the Seattle-Tacoma metropolitan area, and its drainage system via the Columbia River potentially affects another 500,000 residents of southwestern Washington and northwestern Oregon (Figure 1). Mount Rainier is the most hazardous volcano in the Cascades in terms of its potential for magma-water interaction and sector collapse. Major eruptions, or debris flows even without eruption, pose significant dangers and economic threats to the region. Despite such hazard and risk, Mount Rainier has received little study; such important topics as its petrologic and geochemical character, its proximal eruptive history, its susceptibility to major edifice failure, and its development over time have been barely investigated. This situation may soon change because of Mount Rainier's recent designation as a “Decade Volcano.”

System for ranking relative threats of U.S. volcanoes

USGS Publications Warehouse

Ewert, J.W.

2007-01-01

A methodology to systematically rank volcanic threat was developed as the basis for prioritizing volcanoes for long-term hazards evaluations, monitoring, and mitigation activities. A ranking of 169 volcanoes in the United States and the Commonwealth of the Northern Mariana Islands (U.S. volcanoes) is presented based on scores assigned for various hazard and exposure factors. Fifteen factors define the hazard: Volcano type, maximum known eruptive explosivity, magnitude of recent explosivity within the past 500 and 5,000 years, average eruption-recurrence interval, presence or potential for a suite of hazardous phenomena (pyroclastic flows, lahars, lava flows, tsunami, flank collapse, hydrothermal explosion, primary lahar), and deformation, seismic, or degassing unrest. Nine factors define exposure: a measure of ground-based human population in hazard zones, past fatalities and evacuations, a measure of airport exposure, a measure of human population on aircraft, the presence of power, transportation, and developed infrastructure, and whether or not the volcano forms a significant part of a populated island. The hazard score and exposure score for each volcano are multiplied to give its overall threat score. Once scored, the ordered list of volcanoes is divided into five overall threat categories from very high to very low. ?? 2007 ASCE.

Volcano geodesy in the Cascade arc, USA

NASA Astrophysics Data System (ADS)

Poland, Michael P.; Lisowski, Michael; Dzurisin, Daniel; Kramer, Rebecca; McLay, Megan; Pauk, Ben

2017-08-01

Experience during historical time throughout the Cascade arc and the lack of deep-seated deformation prior to the two most recent eruptions of Mount St. Helens might lead one to infer that Cascade volcanoes are generally quiescent and, specifically, show no signs of geodetic change until they are about to erupt. Several decades of geodetic data, however, tell a different story. Ground- and space-based deformation studies have identified surface displacements at five of the 13 major Cascade arc volcanoes that lie in the USA (Mount Baker, Mount St. Helens, South Sister, Medicine Lake, and Lassen volcanic center). No deformation has been detected at five volcanoes (Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake, and Mount Shasta), and there are not sufficient data at the remaining three (Glacier Peak, Mount Adams, and Mount Jefferson) for a rigorous assessment. In addition, gravity change has been measured at two of the three locations where surveys have been repeated (Mount St. Helens and Mount Baker show changes, while South Sister does not). Broad deformation patterns associated with heavily forested and ice-clad Cascade volcanoes are generally characterized by low displacement rates, in the range of millimeters to a few centimeters per year, and are overprinted by larger tectonic motions of several centimeters per year. Continuous GPS is therefore the best means of tracking temporal changes in deformation of Cascade volcanoes and also for characterizing tectonic signals so that they may be distinguished from volcanic sources. Better spatial resolution of volcano deformation can be obtained through the use of campaign GPS, semipermanent GPS, and interferometric synthetic aperture radar observations, which leverage the accumulation of displacements over time to improve signal to noise. Deformation source mechanisms in the Cascades are diverse and include magma accumulation and withdrawal, post-emplacement cooling of recent volcanic deposits, magmatic

Volcano geodesy in the Cascade arc, USA

USGS Publications Warehouse

Poland, Michael; Lisowski, Michael; Dzurisin, Daniel; Kramer, Rebecca; McLay, Megan; Pauk, Benjamin

2017-01-01

Experience during historical time throughout the Cascade arc and the lack of deep-seated deformation prior to the two most recent eruptions of Mount St. Helens might lead one to infer that Cascade volcanoes are generally quiescent and, specifically, show no signs of geodetic change until they are about to erupt. Several decades of geodetic data, however, tell a different story. Ground- and space-based deformation studies have identified surface displacements at five of the 13 major Cascade arc volcanoes that lie in the USA (Mount Baker, Mount St. Helens, South Sister, Medicine Lake, and Lassen volcanic center). No deformation has been detected at five volcanoes (Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake, and Mount Shasta), and there are not sufficient data at the remaining three (Glacier Peak, Mount Adams, and Mount Jefferson) for a rigorous assessment. In addition, gravity change has been measured at two of the three locations where surveys have been repeated (Mount St. Helens and Mount Baker show changes, while South Sister does not). Broad deformation patterns associated with heavily forested and ice-clad Cascade volcanoes are generally characterized by low displacement rates, in the range of millimeters to a few centimeters per year, and are overprinted by larger tectonic motions of several centimeters per year. Continuous GPS is therefore the best means of tracking temporal changes in deformation of Cascade volcanoes and also for characterizing tectonic signals so that they may be distinguished from volcanic sources. Better spatial resolution of volcano deformation can be obtained through the use of campaign GPS, semipermanent GPS, and interferometric synthetic aperture radar observations, which leverage the accumulation of displacements over time to improve signal to noise. Deformation source mechanisms in the Cascades are diverse and include magma accumulation and withdrawal, post-emplacement cooling of recent volcanic deposits, magmatic

Volcanoes and climate

NASA Technical Reports Server (NTRS)

Toon, O. B.

1982-01-01

The evidence that volcanic eruptions affect climate is reviewed. Single explosive volcanic eruptions cool the surface by about 0.3 C and warm the stratosphere by several degrees. Although these changes are of small magnitude, there have been several years in which these hemispheric average temperature changes were accompanied by severely abnormal weather. An example is 1816, the "year without summer" which followed the 1815 eruption of Tambora. In addition to statistical correlations between volcanoes and climate, a good theoretical understanding exists. The magnitude of the climatic changes anticipated following volcanic explosions agrees well with the observations. Volcanoes affect climate because volcanic particles in the atmosphere upset the balance between solar energy absorbed by the Earth and infrared energy emitted by the Earth. These interactions can be observed. The most important ejecta from volcanoes is not volcanic ash but sulfur dioxide which converts into sulfuric acid droplets in the stratosphere. For an eruption with its explosive magnitude, Mount St. Helens injected surprisingly little sulfur into the stratosphere. The amount of sulfuric acid formed is much smaller than that observed following significant eruptions and is too small to create major climatic shifts. However, the Mount St. Helens eruption has provided an opportunity to measure many properties of volcanic debris not previously measured and has therefore been of significant value in improving our knowledge of the relations between volcanic activity and climate.

A field guide to Newberry Volcano, Oregon

USGS Publications Warehouse

Jenson, Robert A.; Donnelly-Nolan, Julie M.; McKay, Daniele

2009-01-01

Newberry Volcano is located in central Oregon at the intersection of the Cascade Range and the High Lava Plains. Its lavas range in age from ca. 0.5 Ma to late Holocene. Erupted products range in composition from basalt through rhyolite and cover ~3000 km2. The most recent caldera-forming eruption occurred ~80,000 years ago. This trip will highlight a revised understanding of the volcano's history based on new detailed geologic work. Stops will also focus on evidence for ice and flooding on the volcano, as well as new studies of Holocene mafic eruptions. Newberry is one of the most accessible U.S. volcanoes, and this trip will visit a range of lava types and compositions including tholeiitic and calc-alkaline basalt flows, cinder cones, and rhyolitic domes and tuffs. Stops will include early distal basalts as well as the youngest intracaldera obsidian flow.

Radial anisotropy ambient noise tomography of volcanoes

NASA Astrophysics Data System (ADS)

Mordret, Aurélien; Rivet, Diane; Shapiro, Nikolai; Jaxybulatov, Kairly; Landès, Matthieu; Koulakov, Ivan; Sens-Schönfelder, Christoph

2016-04-01

The use of ambient seismic noise allows us to perform surface-wave tomography of targets which could hardly be imaged by other means. The frequencies involved (~ 0.5 - 20 s), somewhere in between active seismic and regular teleseismic frequency band, make possible the high resolution imaging of intermediate-size targets like volcanic edifices. Moreover, the joint inversion of Rayleigh and Love waves dispersion curves extracted from noise correlations allows us to invert for crustal radial anisotropy. We present here the two first studies of radial anisotropy on volcanoes by showing results from Lake Toba Caldera, a super-volcano in Indonesia, and from Piton de la Fournaise volcano, a hot-spot effusive volcano on the Réunion Island (Indian Ocean). We will see how radial anisotropy can be used to infer the main fabric within a magmatic system and, consequently, its dominant type of intrusion.

Three-dimensional stochastic adjustment of volcano geodetic network in Arenal volcano, Costa Rica

NASA Astrophysics Data System (ADS)

Muller, C.; van der Laat, R.; Cattin, P.-H.; Del Potro, R.

2009-04-01

Volcano geodetic networks are a key instrument to understanding magmatic processes and, thus, forecasting potentially hazardous activity. These networks are extensively used on volcanoes worldwide and generally comprise a number of different traditional and modern geodetic surveying techniques such as levelling, distances, triangulation and GNSS. However, in most cases, data from the different methodologies are surveyed, adjusted and analysed independently. Experience shows that the problem with this procedure is the mismatch between the excellent correlation of position values within a single technique and the low cross-correlation of such values within different techniques or when the same network is surveyed shortly after using the same technique. Moreover one different independent network for each geodetic surveying technique strongly increase logistics and thus the cost of each measurement campaign. It is therefore important to develop geodetic networks which combine the different geodetic surveying technique, and to adjust geodetic data together in order to better quantify the uncertainties associated to the measured displacements. In order to overcome the lack of inter-methodology data integration, the Geomatic Institute of the University of Applied Sciences of Western Switzerland (HEIG-VD) has developed a methodology which uses a 3D stochastic adjustment software of redundant geodetic networks, TRINET+. The methodology consists of using each geodetic measurement technique for its strengths relative to other methodologies. Also, the combination of the measurements in a single network allows more cost-effective surveying. The geodetic data are thereafter adjusted and analysed in the same referential frame. The adjustment methodology is based on the least mean square method and links the data with the geometry. Trinet+ also allows to run a priori simulations of the network, hence testing the quality and resolution to be expected for a determined network even

2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF MEDIAN. NOTE VOLCANIC STONE CURBING (EDGING) TYPICAL OF MOST PARKING AREAS; TRIANGLING AT END NOT TYPICAL. MAUNA LOA VOLCANO IN BACK. - Crater Rim Drive, Volcano, Hawaii County, HI

Deep structure of Llaima Volcano from seismic ambient noise tomography: Preliminary results

NASA Astrophysics Data System (ADS)

Franco, L.; Mikesell, T. D.; Rodd, R.; Lees, J. M.; Johnson, J. B.; Ronan, T.

2015-12-01

The ambient seismic noise tomography (ANT) method has become an important tool to image crustal structures and magmatic bodies at volcanoes. The frequency band of ambient noise provides complimentary data and added resolution to the deeper volcanic structures when compared to traditional tomography based on local earthquakes. The Llaima Volcano (38° 41.9' S and 71° 43.8' W) is a stratovolcano of basaltic-andesitic composition. Llaima is located in the South Volcanic Zone (ZVS) of the Andes and is listed as one of the most active volcanoes in South America, with a long documented historical record dating back to 1640. Llaima experienced violent eruptions in 1927 and 1957 (Naranjo and Moreno, 1991), and its last eruptive cycle (2008-2010) is considered the most important after the 1957 eruption. Lacking seismic constraints on the deep structure under Llaima, petrologic data have suggested the presence of magmatic bodies (dikes). These bodies likely play an important role in the eruptive dynamics of Llaima (Bouvet de Maisonneuve, C., et al 2012). Analysis of the 2008-2010 seismicity shows a southern zone (approx. 15 km from the Llaima summit) where there were many Very Long Period events occurring prior to the eruptions. This is in agreement with a deformation zone determined by InSAR analysis (Fournier et al, 2010 and Bathke, 2011), but no geologic model based on geophysical imaging has been created yet. Beginning in 2009, staff from the Chilean Geological Survey (SERNAGEOMIN) started to install a permanent seismic network consisting of nine stations. These nine stations have allowed Chilean seismologists to closely monitor the activity at Llaima, but prevented a high-resolution tomographic imaging study. During the summer of 2015, a temporary seismic network consisting of 26 stations was installed around Llaima. In the work presented here, we analyze continuous waveforms recorded between January and April 2015 from a total of 35 broadband stations (permanent and

Mount Meager Volcano, Canada: a Case Study for Landslides on Glaciated Volcanoes

NASA Astrophysics Data System (ADS)

Roberti, G. L.; Ward, B. C.; van Wyk de Vries, B.; Falorni, G.; Perotti, L.; Clague, J. J.

2015-12-01

Mount Meager is a strato-volcano massif in the Northern Cascade Volcanic Arc (Canada) that erupted in 2350 BP, the most recent in Canada. To study the stability of the Massif an international research project between France ( Blaise Pascal University), Italy (University of Turin) and Canada (Simon Fraser University) and private companies (TRE - sensing the planet) has been created. A complex history of glacial loading and unloading, combined with weak, hydrothermally altered rocks has resulted in a long record of catastrophic landslides. The most recent, in 2010 is the third largest (50 x 106 m3) historical landslide in Canada. Mount Meager is a perfect natural laboratory for gravity and topographic processes such as landslide activity, permafrost and glacial dynamics, erosion, alteration and uplift on volcanoes. Research is aided by a rich archive of aerial photos of the Massif (1940s up to 2006): complete coverage approximately every 10 years. This data set has been processed and multi-temporal, high resolution Orthophoto and DSMs (Digital Surface Models) have been produced. On these digital products, with the support on field work, glacial retreat and landslide activity have been tracked and mapped. This has allowed for the inventory of unstable areas, the identification of lava flows and domes, and the general improvement on the geologic knowledge of the massif. InSAR data have been used to monitor the deformation of the pre-2010 failure slope. It will also be used to monitor other unstable slopes that potentially can evolve to catastrophic collapses of up to 1 km3 in volume, endangering local communities downstream the volcano. Mount Meager is definitively an exceptional site for studying the dynamics of a glaciated, uplifted volcano. The methodologies proposed can be applied to other volcanic areas with high erosion rates such as Alaska, Cascades, and the Andes.

Instability of Hawaiian volcanoes: Chapter 4 in Characteristics of Hawaiian volcanoes

USGS Publications Warehouse

Denlinger, Roger P.; Morgan, Julia K.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

2014-01-01

All seaward flank movement occurs along a detachment fault, or décollement, that forms within the mixture of pelagic clays and volcaniclastic deposits on the old seafloor and pushes up a bench of debris along the distal margin of the flank. The offshore uplift that builds this bench is generated by décollement slip that terminates upward into the overburden along thrust faults. Finite strain and finite strength models for volcano growth on a low-friction décollement reproduce this bench structure, as well as much of the morphology and patterns of faulting observed on the actively growing volcanoes of Mauna Loa and Kīlauea. These models show how stress is stored within growing volcano flanks, but not how rapid, potentially seismic slip is triggered along their décollements. The imbalance of forces that triggers large, rapid seaward displacement of the flank after decades of creep may result either from driving forces that change rapidly, such as magma pressure gradients; from resisting forces that rapidly diminish with slip, such as those arising from coupling of pore pressure and dilatancy within décollement sediment; or, from some interplay between driving and resisting forces that produces flank motion. Our understanding of the processes of flank motion is limited by available data, though recent studies have increased our ability to quantitatively address flank instability and associated hazards.

ICE-VOLC Project: unravelling the dynamics of Antarctica volcanoes

NASA Astrophysics Data System (ADS)

Cannata, Andrea; Del Carlo, Paola; Giudice, Gaetano; Giuffrida, Giovanni; Larocca, Graziano; Liuzzo, Marco

2017-04-01

Melbourne and Rittmann volcanoes are located in the Victoria Land. Whilst Rittmann's last eruption dates probably to Pleistocene, Melbourne's most recent eruption between 1862 and 1922, testifying it is still active. At present, both volcanoes display fumarolic activity. Melbourne was discovered in 1841 by James Clark Ross, Rittmann during the 4th Italian Expedition (1988/1989). Our knowledge on both volcanoes is really little. The position of these volcanoes in the Antarctic region (characterised by absence of anthropic noise) and its proximity with the Italian Mario Zucchelli Station makes them ideal sites for studying volcano seismic sources, geothermal emissions, seismo-acoustic signals caused by cryosphere-hydrosphere-atmosphere dynamics, and volcanic gas impact on environment. Hence, the main aim of the ICE-VOLC ("multiparametrIC Experiment at antarctica VOLCanoes: data from volcano and cryosphere-ocean-atmosphere dynamics") project is the study of Melbourne and Rittmann, by acquisition, analysis and integration of multiparametric geophysical, geochemical and thermal data. Complementary objectives include investigation of the relationship between seismo-acoustic activity recorded in Antarctica and cryosphere-hydrosphere-atmosphere dynamics, evaluation of the impact of volcanic gas in atmosphere. This project involves 26 researchers, technologists and technicians from University of Perugia and from Istituto Nazionale di Geofisica e Vulcanologia of Catania, Palermo, Pisa and Rome. In this work, we show the preliminary results obtained after the first expedition in Antarctica, aiming to perform geochemical-thermal surveys in the volcano ice caves, as well as to collect ash samples and to install temporary seismic stations.

Interferometric Synthetic Aperture radar studies of Alaska volcanoes

USGS Publications Warehouse

Lu, Zhong; Wicks, Charles W.; Dzurisin, Daniel; Power, John A.; Thatcher, Wayne R.; Masterlark, Timothy

2003-01-01

In this article, we summarize our recent InSAR studies of 13 Alaska volcanoes, including New Trident, Okmok, Akutan, Kiska, Augustine, Westdahl, Peulik, Makushin, Seguam, Shishaldin, Pavlof, Cleveland, and Korovin volcanoes.

NASA Spacecraft Spots Signs of Erupting Russian Volcano

NASA Image and Video Library

2014-05-20

Winter still grips the volcanoes on Russia Kamchatka peninsula. NASA Terra spacecraft acquired this image showing the mantle of white, disturbed by dark ash entirely covering Sheveluch volcano from recent eruptions.

The diversity of mud volcanoes in the landscape of Azerbaijan

NASA Astrophysics Data System (ADS)

Rashidov, Tofig

2014-05-01

As the natural phenomenon the mud volcanism (mud volcanoes) of Azerbaijan are known from the ancient times. The historical records describing them are since V century. More detail study of this natural phenomenon had started in the second half of XIX century. The term "mud volcano" (or "mud hill") had been given by academician H.W. Abich (1863), more exactly defining this natural phenomenon. All the previous definitions did not give such clear and capacious explanation of it. In comparison with magmatic volcanoes, globally the mud ones are restricted in distribution; they mainly locate within the Alpine-Himalayan, Pacific and Central Asian mobile belts, in more than 30 countries (Columbia, Trinidad Island, Italy, Romania, Ukraine, Georgia, Azerbaijan, Turkmenistan, Iran, Pakistan, Indonesia, Burma, Malaysia, etc.). Besides it, the zones of mud volcanoes development are corresponded to zones of marine accretionary prisms' development. For example, the South-Caspian depression, Barbados Island, Cascadia (N.America), Costa-Rica, Panama, Japan trench. Onshore it is Indonesia, Japan, and Trinidad, Taiwan. The mud volcanism with non-accretionary conditions includes the areas of Black Sea, Alboran Sea, the Gulf of Mexico (Louisiana coast), Salton Sea. But new investigations reveal more new mud volcanoes and in places which were not considered earlier as the traditional places of mud volcanoes development (e.g. West Nile Rive delta). Azerbaijan is the classic region of mud volcanoes development. From over 800 world mud volcanoes there are about 400 onshore and within the South-Caspian basin, which includes the territory of East Azerbaijan (the regions of Shemakha-Gobustan and Low-Kura River, Absheron peninsula), adjacent water area of South Caspian (Baku and Absheron archipelagoes) and SW Turkmenistan and represents an area of great downwarping with thick (over 25 km) sedimentary series. Generally, in the modern relief the mud volcanoes represent more or less large uplifts

Geochemical evolution of Kohala Volcano, Hawaii

USGS Publications Warehouse

Lanphere, M.A.; Frey, F.A.

1987-01-01

Kohala Volcano, the oldest of five shield volcanoes comprising the island of Hawaii, consists of a basalt shield dominated by tholeiitic basalt, Pololu Volcanics, overlain by alkalic lavas, Hawi Volcanics. In the upper Pololu Volcanics the lavas become more enriched in incompatible elements, and there is a transition from tholeiitic to alkalic basalt. In contrast, the Hawi volcanics consist of hawaiites, mugearites, and trachytes. 87Sr/86Sr ratios of 14 Pololu basalts and 5 Hawi lavas range from 0.70366 to 0.70392 and 0.70350 to 0.70355, respectively. This small but distinct difference in Sr isotopic composition of different lava types, especially the lower 87Sr/86Sr in the younger lavas with higher Rb/Sr, has been found at other Hawaiian volcanoes. Our data do not confirm previous data indicating Sr isotopic homogeneity among lavas from Kohala Volcano. Also some abundance trends, such as MgO-P2O5, are not consistent with a simple genetic relationship between Pololu and Hawi lavas. We conclude that all Kohala lavas were not produced by equilibrium partial melting of a compositionally homogeneous source. ?? 1987 Springer-Verlag.

Relative chronology of Martian volcanoes

NASA Technical Reports Server (NTRS)

Landheim, R.; Barlow, N. G.

1991-01-01

Impact cratering is one of the major geological processes that has affected the Martian surface throughout the planet's history. The frequency of craters within particular size ranges provides information about the formation ages and obliterative episodes of Martian geologic units. The Barlow chronology was extended by measuring small craters on the volcanoes and a number of standard terrain units. Inclusions of smaller craters in units previously analyzed by Barlow allowed for a more direct comparison between the size-frequency distribution data for volcanoes and established chronology. During this study, 11,486 craters were mapped and identified in the 1.5 to 8 km diameter range in selected regions of Mars. The results are summarized in this three page report and give a more precise estimate of the relative chronology of the Martian volcanoes. Also, the results of this study lend further support to the increasing evidence that volcanism has been a dominant geologic force throughout Martian history.

Microbial biodiversity of Tang and Pirgal mud volcanoes and evaluation of bio-emulsifier and bio-demulsifier activities of Capnophile bacteria.

PubMed

Parsia, Yasaman; Sorooshian, Shahryar

2017-12-01

The data presented in this article is related to the Master thesis; entitled "Survey Aerobic Microbial Diversity Mud Volcanoes in Chabahar and Khash Ports in Southern Iran" by the first author of this article, year 2011, Islamic Azad University, Iran (reference number (Parsia, 2011) [1] of this article). This article shows microbial biodiversity and evaluates bio-emulsifier and bio-demulsifier abilities of capnophile isolates, in order to introduce a superior isolate for the Microbial Enhanced Oil Recovery (MEOR) process in the petrochemical industry.

Two magma bodies beneath the summit of Kilauea Volcano unveiled by isotopically distinct melt deliveries from the mantle

USGS Publications Warehouse

Pietruszka, Aaron J.; Heaton, Daniel E.; Marske, Jared P.; Garcia, Michael O.

2015-01-01

The summit magma storage reservoir of Kīlauea Volcano is one of the most important components of the magmatic plumbing system of this frequently active basaltic shield-building volcano. Here we use new high-precision Pb isotopic analyses of Kīlauea summit lavas—from 1959 to the active Halema‘uma‘u lava lake—to infer the number, size, and interconnectedness of magma bodies within the volcano's summit reservoir. From 1971 to 1982, the 206Pb/204Pb ratios of the lavas define two separate magma mixing trends that correlate with differences in vent location and/or pre-eruptive magma temperature. These relationships, which contrast with a single magma mixing trend for lavas from 1959 to 1968, indicate that Kīlauea summit eruptions since at least 1971 were supplied from two distinct magma bodies. The locations of these magma bodies are inferred to coincide with two major deformation centers identified by geodetic monitoring of the volcano's summit region: (1) the main locus of the summit reservoir ∼2–4 km below the southern rim of Kīlauea Caldera and (2) a shallower magma body <2 km below the eastern rim of Halema‘uma‘u pit crater. Residence time modeling suggests that the total volume of magma within Kīlauea's summit reservoir during the late 20th century (1959–1982) was exceedingly small (∼0.1–0.5 km3). Voluminous Kīlauea eruptions, such as the ongoing, 32-yr old Pu‘u ‘Ō‘ō rift eruption (>4 km3 of lava erupted), must therefore be sustained by a nearly continuous supply of new melt from the mantle. The model results show that a minimum of four compositionally distinct, mantle-derived magma batches were delivered to the volcano (at least three directly to the summit reservoir) since 1959. These melt inputs correlate with the initiation of energetic (1959 Kīlauea Iki) and/or sustained (1969–1974 Mauna Ulu, 1983-present Pu‘u ‘Ō‘ō and 2008-present Halema‘uma‘u) eruptions. Thus, Kīlauea's eruptive behavior is partly tied to

The Evolution of Galápagos Volcanoes: An Alternative Perspective

NASA Astrophysics Data System (ADS)

Harpp, Karen S.; Geist, Dennis J.

2018-05-01

The older eastern Galápagos are different in almost every way from the historically active western Galápagos volcanoes. The western Galápagos volcanoes have steep upper slopes and are topped by large calderas, whereas none of the older islands has a caldera, an observation that is supported by recent gravity measurements. Moreover, the eastern islands tend to have been constructed by linear fissure systems and many are cut by faults. Most of the western volcanoes erupt evolved basalts with an exceedingly small range of Mg#, Lan/Smn, and Smn/Ybn. This is attributed to homogenization in a crustal-scale magmatic mush column, which is maintained in a thermochemical steady state, owing to high magma supply directly over the Galápagos mantle plume. The exceptions are volcanoes at the leading edge of the hotspot, which have yet to develop mush columns, and volcanoes that are waning in activity, because they are being carried away from the plume. In contrast, the eastern volcanoes erupt relatively primitive magmas, with a large range in Mg#, Lan/Smn, and Smn/Ybn. This is attributed to isolated, ephemeral magmatic plumbing systems supplied by smaller magmatic fluxes throughout their histories. Consequently, each batch of magma follows an independent course of evolution, owing to the low volume of hypersolidus material beneath these volcanoes. The magmatic flux to Galápagos volcanoes negatively correlates with the distance to the Galápagos Spreading Center (GSC). When the ridge was close to the plume, most of the plume-derived magma was directed to the ridge. Currently, the active volcanoes are much farther from the GSC, thus most of the plume-derived magma erupts on the Nazca Plate and can be focused beneath the large young shields. We define an intermediate sub-province comprising Rabida, Santiago and Pinzon volcanoes, which were most active about 1 Ma. They have all erupted dacites, rhyolites, and trachytes, similar to the dying stage of the western volcanoes

Characteristics and petrology of the effusive-explosive activity of Colima volcano, in the years 2015-2017

NASA Astrophysics Data System (ADS)

Suarez-Plascencia, C.; Nuñez-Cornu, F. J.; Arreola-Ochoa, L. C.; Suarez, G. B. V.; Carrillo-Gonzalez, D. A.

2017-12-01

The Colima volcano, during the years 2015-2017, presented an important effusive and explosive activity, which began in January 2015 with the growth of a dome that was destroyed by explosions, forming pyroclastic flows reaching distances of up to 2 km by the north and south flanks of the volcano. In May a new dome was extruded, forming three thick lava flows along the northern and southern slopes; the extruded volume was approximately 6 million cubic meters, with a rate in 52 days of 1.3 m3/sec. On July 11 merapi flows were formed it flowed through by the ravines of Montegrande and San Antonio, on the south and southwest flank, reaching distances of 10.4 km. The following days the activity had decreased substantially, leaving a crater of 60 m of depth and 270 m of diameter. In February 2016, a small dome occupied the central part of the main crater, and it was until September that an episode of volcanic tremor began, that was associated with its rapid growth, which in 48 hours filled the crater and formed a lava flow that descended by the south slope. By October 2, 2.3 million m3 of lava were extruded, which caused a deflation of the dome. In October 7, the volcano emitted a great amount of gases and steam of water that formed an acid rain that affected forests and crops of the south and southwest slope, causing losses by 1 million dollars. In November, a series of explosions occurred that destroyed two thirds of the dome. In January 2017, the explosive activity increased and again destroyed the dome. Five events were recorded that reached between 3 km and 4 km of height on the top of the volcano, the dispersion of the ash generally went to the northeast, reaching distances of up to 200 km. Currently the volcano is sustaining reduced seismic and fumarole activity. In 2005, 2015 and 2017, the geochemical analysis of major elements such as SiO2 from the ash emitted by the volcano showed an increase from 54.51% to 60.05% and 60.24%, respectively, which was associated

Similar soil microbial community structure across different environments after long-term succession: evidence from volcanoes of different ages.

PubMed

Xu, Shangqi; Zhang, Jianfeng; Luo, Shasha; Zhou, Xue; Shi, Shaohua; Tian, Chunjie

2018-06-08

Soil microbes play critical roles in global biogeochemical cycles, but their succession patterns across long temporal scales have rarely been studied. In this study, soil samples were collected from three volcanoes in Wudalianchi, northeastern China: Laoheishan (LH, approximately 240 years old), Dongjiaodebushan (DJ, 0.45-0.6 million years old), and Nangelaqiushan (NG, 0.8-1.3 million years old). For each volcano, both southern (S) and northern (N) slope aspects were sampled. Soil microbial communities were analyzed using phospholipid fatty acid analysis (PLFA). The results showed that soil properties and microbial biomass changed perceptibly among different volcanoes and different slope aspects. Almost all of the detected soil nutrient contents of LH were lowest, and total microbial biomass of LH was 40 and 36% lower than those of NG and DJ, respectively. LH was significantly different from NG and DJ in soil microbial community structure with a higher relative abundance of fungi and a lower relative abundance of actinomycetes and bacteria. However, for the two ancient volcanoes (NG and DJ), soil microbial community structures were highly similar among different ages and different slope aspects. No difference was detected in any of the measured microbial indices, including richness, evenness, Shannon's diversity, Simpson's diversity and the relative abundance of different microbial groups. The results indicated that while soil microbial biomass may change across different soil environments after long-term succession, soil microbial community structure can remain relatively stable. The results further indicated that soil microbes may show different successional patterns in different stages of succession. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Translating Volcano Hazards Research in the Cascades Into Community Preparedness

NASA Astrophysics Data System (ADS)

Ewert, J. W.; Driedger, C. L.

2015-12-01

Research by the science community into volcanic histories and physical processes at Cascade volcanoes in the states of Washington, Oregon, and California has been ongoing for over a century. Eruptions in the 20th century at Lassen Peak and Mount St. Helen demonstrated the active nature of Cascade volcanoes; the 1980 eruption of Mount St. Helens was a defining moment in modern volcanology. The first modern volcano hazards assessments were produced by the USGS for some Cascade volcanoes in the 1960s. A rich scientific literature exists, much of which addresses hazards at these active volcanoes. That said community awareness, planning, and preparation for eruptions generally do not occur as a result of a hazard analyses published in scientific papers, but by direct communication with scientists. Relative to other natural hazards, volcanic eruptions (or large earthquakes, or tsunami) are outside common experience, and the public and many public officials are often surprised to learn of the impacts volcanic eruptions could have on their communities. In the 1980s, the USGS recognized that effective hazard communication and preparedness is a multi-faceted, long-term undertaking and began working with federal, state, and local stakeholders to build awareness and foster community action about volcano hazards. Activities included forming volcano-specific workgroups to develop coordination plans for volcano emergencies; a concerted public outreach campaign; curriculum development and teacher training; technical training for emergency managers and first responders; and development of hazard information that is accessible to non-specialists. Outcomes include broader ownership of volcano hazards as evidenced by bi-national exchanges of emergency managers, community planners, and first responders; development by stakeholders of websites focused on volcano hazards mitigation; and execution of table-top and functional exercises, including evacuation drills by local communities.

Augustine Volcano, Cook Inlet, Alaska January 31, 2006

NASA Image and Video Library

2006-02-02

Since last spring, the U.S. Geological Survey Alaska Volcano Observatory AVO has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. This image is from NASA Terra spacecraft.

Augustine Volcano, Cook Inlet, Alaska January 12, 2006

NASA Image and Video Library

2006-02-02

Since last spring, the U.S. Geological Survey Alaska Volcano Observatory AVO has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. This image is from NASA Terra spacecraft.

Experimental simulation and morphological quantification of volcano growth

NASA Astrophysics Data System (ADS)

Grosse, Pablo; Kervyn, Matthieu; Gallland, Olivier; Delcamp, Audray; Poppe, Sam

2016-04-01

Volcanoes display very diverse morphologies as a result of a complex interplay of several constructive and destructive processes. Here the role played by the spatial distribution of eruption centre and by an underlying strike-slip fault in controlling the long term growth of volcanoes is investigated with analogue models. Volcano growth was simulated by depositing loads of granular material (sand-kaolin mixtures) from a point source. An individual load deposited at a fixed location produces a simple symmetrical cone with flank slopes at the angle of repose of the granular material (~33°) that can be considered as the building-block for the experiments. Two sets of experiments were undertaken: (1) the location of deposition of the granular material (i.e. the volcano growth location) was shifted with time following specific probability density functions simulating shifts or migrations in vent location; (2) the location of deposition was kept fixed, but the deposition rate (i.e. the volcano growth rate) was varied coupled with the movement of a basal plate attached to a step-motor simulating a strike-slip displacement under the growing cone (and hence deformation of the cone). During the progression of the experiments, the models were photographed at regular time intervals using four digital cameras positioned at slightly different angles over the models. The photographs were used to generate synthetic digital elevation models (DEMs) with 0.2 mm spatial resolution of each step of the models by applying the MICMAC digital stereo-photogrammetry software. Morphometric data were extracted from the DEMs by applying two IDL-language algorithms: NETVOLC, used to automatically calculate the volcano edifice basal outline, and MORVOLC, used to extract a set of morphometric parameters that characterize the volcano edifice in terms of size, plan shape, profile shape and slopes. Analysis of the DEM-derived morphometric parameters allows to quantitatively characterize the growth

Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

USGS Publications Warehouse

Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

2003-01-01

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

Using the Landsat Thematic Mapper to detect and monitor active volcanoes - An example from Lascar volcano, northern Chile

NASA Technical Reports Server (NTRS)

Francis, P. W.; Rothery, D. A.

1987-01-01

The Landsat Thematic Mapper (TM) offers a means of detecting and monitoring thermal features of active volcanoes. Using the TM, a prominent thermal anomaly has been discovered on Lascar volcano, northern Chile. Data from two short-wavelength infrared channels of the TM show that material within a 300-m-diameter pit crater was at a temperature of at least 380 C on two dates in 1985. The thermal anomaly closely resembles in size and radiant temperature the anomaly over the active lava lake at Erta'ale in Ethiopia. An eruption took place at Lascar on Sept. 16, 1986. TM data acquired on Oct. 27, 1986, revealed significant changes within the crater area. Lascar is in a much more active state than any other volcano in the central Andes, and for this reason it merits further careful monitoring. Studies show that the TM is capable of confidently identifying thermal anomalies less than 100 m in size, at temperatures of above 150 C, and thus it offers a valuable means of monitoring the conditions of active or potentially active volcanoes, particularly those in remote regions.

Hazard maps of Colima volcano, Mexico

NASA Astrophysics Data System (ADS)

Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Escudero Ayala, C. R.

2011-12-01

Colima volcano, also known as Volcan de Fuego (19° 30.696 N, 103° 37.026 W), is located on the border between the states of Jalisco and Colima and is the most active volcano in Mexico. Began its current eruptive process in February 1991, in February 10, 1999 the biggest explosion since 1913 occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching attitudes between 4,500 and 9,000 m.a.s.l., further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events ash emissions were generated in all directions reaching distances up to 100 km, slightly affected nearby villages as Tuxpan, Tonila, Zapotlán, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During the 2005 this volcano has had an intense effusive-explosive activity, similar to the one that took place during the period of 1890 through 1900. Intense pre-plinian eruption in January 20, 1913, generated little economic losses in the lower parts of the volcano due to low population density and low socio-economic activities at the time. Shows the updating of the volcanic hazard maps published in 2001, where we identify whit SPOT satellite imagery and Google Earth, change in the land use on the slope of volcano, the expansion of the agricultural frontier on the east and southeast sides of the Colima volcano, the population inhabiting the area is approximately 517,000 people, and growing at an annual rate of 4.77%, also the region that has shown an increased in the vulnerability for the development of economic activities, supported by the construction of highways, natural gas pipelines and electrical infrastructure that connect to the Port of Manzanillo to Guadalajara city. The update the hazard maps are: a) Exclusion areas and moderate hazard for explosive events

Nabro and Mallahle Volcanoes, Eritrea and Ethiopia, SRTM Colored Height and Shaded Relief

NASA Technical Reports Server (NTRS)

2004-01-01

The area known as the Afar Triangle is located at the northern end of the East Africa Rift, where it approaches the southeastern end of the Red Sea and the southwestern end of the Gulf of Aden. The East African Rift, the Red Sea, and the Gulf of Aden are all zones where Earth's crust is pulling apart in a process known as crustal spreading. Their three-way meeting is known as a triple junction, and their spreading creates a triangular topographic depression for which the area was named.

Not surprisingly, the topographic effects of crustal spreading are more dramatic in the Afar Triangle than anywhere else upon Earth's landmasses. The spreading is primarily evident as patterns of numerous tension cracks. But some of these cracks provide conduits for magma to rise to the surface to form volcanoes.

Shown here are a few of the volcanoes of the Afar Triangle. The larger two are Nabro Volcano (upper right, in Eritrea) and Mallahle Volcano (lower left, in Ethiopia). Nabro Volcano shows clear evidence of multiple episodes of activity that resulted in a crater in a crater in a crater. Many volcanoes in this area are active, including one nearby that last erupted in 1990.

This image was created directly from an SRTM elevation model. A shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark. The shade image was then combined with a color coding of topographic height, with green at the lower elevations, rising through yellow, orange, and red, up to purple at the highest elevations.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three

One hundred years of volcano monitoring in Hawaii

USGS Publications Warehouse

Kauahikaua, Jim; Poland, Mike

2012-01-01

In 2012 the Hawaiian Volcano Observatory (HVO), the oldest of five volcano observatories in the United States, is commemorating the 100th anniversary of its founding. HVO's location, on the rim of Kilauea volcano (Figure 1)—one of the most active volcanoes on Earth—has provided an unprecedented opportunity over the past century to study processes associated with active volcanism and develop methods for hazards assessment and mitigation. The scientifically and societally important results that have come from 100 years of HVO's existence are the realization of one man's vision of the best way to protect humanity from natural disasters. That vision was a response to an unusually destructive decade that began the twentieth century, a decade that saw almost 200,000 people killed by the effects of earthquakes and volcanic eruptions.

One hundred years of volcano monitoring in Hawaii

USGS Publications Warehouse

Kauahikaua, J.; Poland, M.

2012-01-01

In 2012 the Hawaiian Volcano Observatory (HVO), the oldest of five volcano observatories in the United States, is commemorating the 100th anniversary of its founding. HVO's location, on the rim of Klauea volcano (Figure 1)one of the most active volcanoes on Earthhas provided an unprecedented opportunity over the past century to study processes associated with active volcanism and develop methods for hazards assessment and mitigation. The scientifically and societally important results that have come from 100 years of HVO's existence are the realization of one man's vision of the best way to protect humanity from natural disasters. That vision was a response to an unusually destructive decade that began the twentieth century, a decade that saw almost 200,000 people killed by the effects of earthquakes and volcanic eruptions.

Near-specular acoustic scattering from a buried submarine mud volcano.

PubMed

Gerig, Anthony L; Holland, Charles W

2007-12-01

Submarine mud volcanoes are objects that form on the seafloor due to the emission of gas and fluidized sediment from the Earth's interior. They vary widely in size, can be exposed or buried, and are of interest to the underwater acoustics community as potential sources of active sonar clutter. Coincident seismic reflection data and low frequency bistatic scattering data were gathered from one such buried mud volcano located in the Straits of Sicily. The bistatic data were generated using a pulsed piston source and a 64-element horizontal array, both towed over the top of the volcano. The purpose of this work was to appropriately model low frequency scattering from the volcano using the bistatic returns, seismic bathymetry, and knowledge of the general geoacoustic properties of the area's seabed to guide understanding and model development. Ray theory, with some approximations, was used to model acoustic propagation through overlying layers. Due to the volcano's size, scattering was modeled using geometric acoustics and a simple representation of volcano shape. Modeled bistatic data compared relatively well with experimental data, although some features remain unexplained. Results of an inversion for the volcano's reflection coefficient indicate that it may be acoustically softer than expected.

Volcanoes in the Classroom--an Explosive Learning Experience.

ERIC Educational Resources Information Center

Thompson, Susan A.; Thompson, Keith S.

1996-01-01

Presents a unit on volcanoes for third- and fourth-grade students. Includes demonstrations; video presentations; building a volcano model; and inviting a scientist, preferably a vulcanologist, to share his or her expertise with students. (JRH)

The Ninole Basalt — Implications for the structural evolution of Mauna Loa volcano, Hawaii

NASA Astrophysics Data System (ADS)

Lipman, Peter W.; Rhodes, J. M.; Dalrymple, G. Brent

1990-12-01

Lava flows of the Ninole Basalt, the oldest rocks exposed on the south side of the island of Hawaii, provide age and compositional constraints on the evolution of Mauna Loa volcano and the southeastward age progression of Hawaiian volcanism. Although the tholeiitic Ninole Basalt differs from historic lavas of Mauna Loa volcano in most major-element contents (e.g., variably lower K, Na, Si; higher Al, Fe, Ti, Ca), REE and other relatively immobile minor elements are similar to historic and prehistoric Mauna Loa lavas, and the present major-element differences are mainly due to incipient weathering in the tropical environment. New K-Ar whole-rock ages, from relatively fresh roadcut samples, suggest that the age of the Ninole Basalt is approximately 0.1 0.2 Ma, although resolution is poor because of low contents of K and radiogenic Ar. Originally considered the remnants of a separate volcano, the Ninole Hills are here interpreted as faulted remnants of the old south flank of Mauna Loa. Deep canyons in the Ninole Hills, eroded after massive landslide failure of flanks of the southwest rift zone, have been preserved from burial by younger lava due to westward migration of the rift zone. Landslide-induced depressurization of the southwest rift zone may also have induced phreatomagmatic eruptions that could have deposited widespread Basaltic ash that overlies the Ninole Basalt. Subaerial presence of the Ninole Basalt documents that the southern part of Hawaii Island had grown to much of its present size above sea level by 0.1 0.2 Ma, and places significant limits on subsequent enlargement of the south flank of Mauna Loa.

Shiveluch and Klyuchevskaya Volcanoes

NASA Technical Reports Server (NTRS)

2007-01-01

A distance of about 80 kilometers (50 miles) separates Shiveluch and Klyuchevskaya Volcanoes on Russia's Kamchatka Peninsula. Despite this distance, however, the two acted in unison on April 26, 2007, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite caught them both erupting simultaneously. ASTER 'sees' a slightly different portion of the light spectrum than human eyes. Besides a portion of visible light, ASTER detects thermal energy, meaning it can detect volcanic activity invisible to human eyes. Inset in each image above is a thermal infrared picture of the volcano's summit. In these insets, dark red shows where temperatures are coolest, and yellowish-white shows where temperatures are hottest, heated by molten lava. Both insets show activity at the crater. In the case of Klyuchevskaya, some activity at the crater is also visible in the larger image. In the larger images, the landscapes around the volcanoes appear in varying shades of blue-gray. Dark areas on the snow surface are likely stains left over from previous eruptions of volcanic ash. Overhead, clouds dot the sky, casting their shadows on the snow, especially southeast of Shiveluch and northeast of Klyuchevskaya. To the northwest of Klyuchevskaya is a large bank of clouds, appearing as a brighter white than the snow surface. Shiveluch (sometimes spelled Sheveluch) and Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) are both stratovolcanoes composed of alternating layers of hardened lava, solidified ash, and rocks from earlier eruptions. Both volcanoes rank among Kamchatka's most active. Because Kamchatka is part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Large-scale plate tectonic activity causing simultaneous volcanic eruptions in Kamchatka is not uncommon.

4D volcano gravimetry

USGS Publications Warehouse

Battaglia, Maurizio; Gottsmann, J.; Carbone, D.; Fernandez, J.

2008-01-01

Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast (hours to weeks), as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera (California, U.S.A.) and Campi Flegrei (Italy), careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological inter-pretations, particularly when the real crust surrounding the source is far from the homogeneous/ isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located (e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography). Applications at Teide volcano (Tenerife) and Campi Flegrei demonstrate the

Establishment, test and evaluation of a prototype volcano surveillance system

NASA Technical Reports Server (NTRS)

Ward, P. L.; Eaton, J. P.; Endo, E.; Harlow, D.; Marquez, D.; Allen, R.

1973-01-01

A volcano-surveillance system utilizing 23 multilevel earthquake counters and 6 biaxial borehole tiltmeters is being installed and tested on 15 volcanoes in 4 States and 4 foreign countries. The purpose of this system is to give early warning when apparently dormant volcanoes are becoming active. The data are relayed through the ERTS-Data Collection System to Menlo Park for analysis. Installation was completed in 1972 on the volcanoes St. Augustine and Iliamna in Alaska, Kilauea in Hawaii, Baker, Rainier and St. Helens in Washington, Lassen in California, and at a site near Reykjavik, Iceland. Installation continues and should be completed in April 1973 on the volcanoes Santiaguito, Fuego, Agua and Pacaya in Guatemala, Izalco in El Salvador and San Cristobal, Telica and Cerro Negro in Nicaragua.

Ground survey of active Central American volcanoes in November - December 1973

NASA Technical Reports Server (NTRS)

Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

1974-01-01

The author has identified the following significant results. Thermal anomalies at two volcanoes, Santiaguito and Izalco, have grown in size in the past six months, based on repeated ground survey. Thermal anomalies at Pacaya volcano have became less intense in the same period. Large (500 m diameter) thermal anomalies exist at 3 volcanoes presently, and smaller scale anomalies are found at nine other volcanoes.

Volcaniclastic stratigraphy of Gede volcano in West Java

NASA Astrophysics Data System (ADS)

Belousov, A.; Belousova, M.; Zaennudin, A.; Prambada, O.

2012-12-01

Gede volcano (2958 m a.s.l.) and the adjacent Pangrango volcano (3019 m a.s.l.) form large (base diameter 35 km) volcanic massif 60 km south of Jakarta. While Pangrango has no recorded eruptions, Gede is one of the most active volcanoes in Indonesia: eruptions were reported 26 times starting from 1747 (Petroeschevsky 1943; van Bemmelen 1949). Historic eruptions were mildly explosive (Vulcanian) with at least one lava flow. Modern activity of the volcano includes persistent solfataric activity in the summit crater and periodic seismic swarms - in 1990, 1991, 1992, 1995, 1996, 1997, 2000, 2010, and 2012 (CVGHM). Lands around the Gede-Pangrango massif are densely populated with villages up to 1500-2000 m a.s.l. Higher, the volcano is covered by rain forest of the Gede-Pangrango Natural Park, which is visited every day by numerous tourists who camp in the summit area. We report the results of the detailed reinvestigation of volcaniclastic stratigraphy of Gede volcano. This work has allowed us to obtain 24 new radiocarbon dates for the area. As a result the timing and character of activity of Gede in Holocene has been revealed. The edifice of Gede volcano consists of main stratocone (Gumuruh) with 1.8 km-wide summit caldera; intra-caldera lava cone (Gede proper) with a 900 m wide summit crater, having 2 breaches toward N-NE; and intra-crater infill (lava dome/flow capped with 3 small craters surrounded by pyroclastic aprons). The Gumuruh edifice, composed mostly of lava flows, comprises more than 90% of the total volume of the volcano. Deep weathering of rocks and thick (2-4 m) red laterite soil covering Gumuruh indicates its very old age. Attempts to get 14C dates in 4 different locations of Gumuruh (including a large debris avalanche deposit on its SE foot) provided ages older than 45,000 years - beyond the limit for 14C dating. Outside the summit caldera, notable volumes of fresh, 14C datable volcaniclastic deposits were found only in the NNE sector of the volcano

Space Radar Image of Sakura-Jima Volcano, Japan

NASA Technical Reports Server (NTRS)

1994-01-01

The active volcano Sakura-Jima on the island of Kyushu, Japan is shown in the center of this radar image. The volcano occupies the peninsula in the center of Kagoshima Bay, which was formed by the explosion and collapse of an ancient predecessor of today's volcano. The volcano has been in near continuous eruption since 1955. Its explosions of ash and gas are closely monitored by local authorities due to the proximity of the city of Kagoshima across a narrow strait from the volcano's center, shown below and to the left of the central peninsula in this image. City residents have grown accustomed to clearing ash deposits from sidewalks, cars and buildings following Sakura-jima's eruptions. The volcano is one of 15 identified by scientists as potentially hazardous to local populations, as part of the international 'Decade Volcano' program. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 9, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 31.6 degrees North latitude and 130.6 degrees East longitude. North is toward the upper left. The area shown measures 37.5 kilometers by 46.5 kilometers (23.3 miles by 28.8 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted, vertically received and C-band vertically transmitted, vertically received; blue is C-band vertically transmitted, vertically received.

Space Radar Image of Sakura-Jima Volcano, Japan

NASA Image and Video Library

1999-04-15

The active volcano Sakura-Jima on the island of Kyushu, Japan is shown in the center of this radar image. The volcano occupies the peninsula in the center of Kagoshima Bay, which was formed by the explosion and collapse of an ancient predecessor of today's volcano. The volcano has been in near continuous eruption since 1955. Its explosions of ash and gas are closely monitored by local authorities due to the proximity of the city of Kagoshima across a narrow strait from the volcano's center, shown below and to the left of the central peninsula in this image. City residents have grown accustomed to clearing ash deposits from sidewalks, cars and buildings following Sakura-jima's eruptions. The volcano is one of 15 identified by scientists as potentially hazardous to local populations, as part of the international "Decade Volcano" program. The image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on October 9, 1994. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered at 31.6 degrees North latitude and 130.6 degrees East longitude. North is toward the upper left. The area shown measures 37.5 kilometers by 46.5 kilometers (23.3 miles by 28.8 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is the average of L-band vertically transmitted, vertically received and C-band vertically transmitted, vertically received; blue is C-band vertically transmitted, vertically received. http://photojournal.jpl.nasa.gov/catalog/PIA01777

Recent Seismicity in the Ceboruco Volcano, Western Mexico

NASA Astrophysics Data System (ADS)

Nunez, D.; Chávez-Méndez, M. I.; Nuñez-Cornu, F. J.; Sandoval, J. M.; Rodriguez-Ayala, N. A.; Trejo-Gomez, E.

2017-12-01

The Ceboruco volcano is the largest (2280 m.a.s.l) of several volcanoes along the Tepic-Zacoalco rift zone in Nayarit state (Mexico). During the last 1000 years, this volcano had effusive-explosive episodes with eight eruptions providing an average of one eruption each 125 years. Since the last eruption occurred in 1870, 147 years ago, a new eruption likelihood is really high and dangerous due to nearby population centers, important roads and lifelines that traverse the volcano's slopes. This hazards indicates the importance of monitoring the seismicity associated with the Ceboruco volcano whose ongoing activity is evidenced by fumaroles and earthquakes. During 2003 and 2008, this region was registered by just one Lennartz Marslite seismograph featuring a Lennartz Le3D sensor (1 Hz) [Rodríguez Uribe et al. (2013)] where they observed that seismicity rates and stresses appear to be increasing indicating higher levels of activity within the volcano. Until July 2017, a semi-permanent network with three Taurus (Nanometrics) and one Q330 Quanterra (Kinemetrics) digitizers with Lennartz 3Dlite sensors of 1 Hz natural frequency was registering in the area. In this study, we present the most recent seismicity obtained by the semi-permanent network and a temporary network of 21 Obsidians 4X and 8X (Kinemetrics) covering an area of 16 km x 16 km with one station every 2.5-3 km recording from November 2016 to July 2017.

Operational Monitoring of Volcanoes Using Keyhole Markup Language

NASA Astrophysics Data System (ADS)

Dehn, J.; Bailey, J. E.; Webley, P.

2007-12-01

Volcanoes are some of the most geologically powerful, dynamic, visually appealing structures on the Earth's landscape. Volcanic eruptions are hard to predict, difficult to quantify and impossible to prevent, making effective monitoring a difficult proposition. In Alaska, volcanoes are an intrinsic part of the culture, with over 100 volcanoes and volcanic fields that have been active in historic time monitored by the Alaska Volcano Observatory (AVO). Observations and research are performed using a suite of methods and tools in the fields of remote sensing, seismology, geodesy and geology, producing large volumes of geospatial data. Keyhole Markup Language (KML) offers a context in which these different, and in the past disparate, data can be displayed simultaneously. Dynamic links keep these data current, allowing it to be used in an operational capacity. KML is used to display information from the aviation color codes and activity alert levels for volcanoes to locations of thermal anomalies, earthquake locations and ash plume modeling. The dynamic refresh and time primitive are used to display volcano webcam and satellite image overlays in near real-time. In addition a virtual globe browser using KML, such as Google Earth, provides an interface to further information using the hyperlink, rich- text and flash-embedding abilities supported within object description balloons. By merging these data sets in an easy to use interface, a virtual globe browser provides a better tool for scientists and emergency managers alike to mitigate volcanic crises.

Understanding cyclic seismicity and ground deformation patterns at volcanoes: Intriguing lessons from Tungurahua volcano, Ecuador

NASA Astrophysics Data System (ADS)

Neuberg, Jürgen W.; Collinson, Amy S. D.; Mothes, Patricia A.; Ruiz, Mario C.; Aguaiza, Santiago

2018-01-01

Cyclic seismicity and ground deformation patterns are observed on many volcanoes worldwide where seismic swarms and the tilt of the volcanic flanks provide sensitive tools to assess the state of volcanic activity. Ground deformation at active volcanoes is often interpreted as pressure changes in a magmatic reservoir, and tilt is simply translated accordingly into inflation and deflation of such a reservoir. Tilt data recorded by an instrument in the summit area of Tungurahua volcano in Ecuador, however, show an intriguing and unexpected behaviour on several occasions: prior to a Vulcanian explosion when a pressurisation of the system would be expected, the tilt signal declines significantly, hence indicating depressurisation. At the same time, seismicity increases drastically. Envisaging that such a pattern could carry the potential to forecast Vulcanian explosions on Tungurahua, we use numerical modelling and reproduce the observed tilt patterns in both space and time. We demonstrate that the tilt signal can be more easily explained as caused by shear stress due to viscous flow resistance, rather than by pressurisation of the magmatic plumbing system. In general, our numerical models prove that if magma shear viscosity and ascent rate are high enough, the resulting shear stress is sufficient to generate a tilt signal as observed on Tungurahua. Furthermore, we address the interdependence of tilt and seismicity through shear stress partitioning and suggest that a joint interpretation of tilt and seismicity can shed new light on the eruption potential of silicic volcanoes.

Geology of Medicine Lake Volcano, Northern California Cascade Range

USGS Publications Warehouse

Donnelly-Nolan, Julie

1990-01-01

Medicine Lake volcano (MLV) is located in an E-W extensional environment on the Modoc Plateau just east of the main arc of the Cascades. It consists mainly of mafic lavas, although drillhole data indicate that a larger volume of rhyolite is present than is indicated by surface mapping. The most recent eruption was rhyolitic and occurred about 900 years ago. At least seventeen eruptions have occurred since 12,000 years ago, or between 1 and 2 eruptions per century on average, although activity appears to be strongly episodic. The calculated eruptive rate is about 0.6 km3 per thousand years during the entire history of the volcano. Drillhole data indicate that the plateau surface underlying the volcano has been downwarped by 0.5 km under the center of MLV. The volcano may be even larger than the estimated 600 km3, already the largest volcano by volume in the Cascades.

Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc

NASA Astrophysics Data System (ADS)

Beaulieu, S.; Hanson, M.; Tunnicliffe, V.; Chadwick, W. W., Jr.; Breuer, E. R.

2016-02-01

In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 and 2010 and ceased as of 2014. NW Rota-1 experienced a massive landslide in late 2009, decimating the habitat on the southern side of the volcano. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching for larvae which have the potential to recolonize the sea floor after such a major disturbance. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument may act as sources for these larvae, but connectivity in this region of complex topography is unknown. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both the zooplankton and benthic community composition in this area of the Monument.

Long- and short-term triggering and modulation of mud volcano eruptions by earthquakes

NASA Astrophysics Data System (ADS)

Bonini, Marco; Rudolph, Maxwell L.; Manga, Michael

2016-03-01

Earthquakes can trigger the eruption of mud. We use eruptions in Azerbaijan, Italy, Romania, Japan, Andaman Islands, Pakistan, Taiwan, Indonesia, and California to probe the nature of stress changes that induce new eruptions and modulate ongoing eruptions. Dynamic stresses produced by earthquakes are usually inferred to be the dominant triggering mechanism; however static stress changes acting on the feeder systems of mud volcanoes may also play a role. In Azerbaijan, eruptions within 2-10 fault lengths from the epicenter are favored in the year following earthquakes where the static stress changes cause compression of the mud source and unclamp feeder dikes. In Romania, Taiwan, and some Italian sites, increased activity is also favored where the static stress changes act to unclamp feeder dikes, but responses occur within days. The eruption in the Andaman Islands, and those of the Niikappu mud volcanoes, Japan are better correlated with amplitude of dynamic stresses produced by seismic waves. Similarly, a new island that emerged off the coast of Pakistan in 2013 was likely triggered by dynamic stresses, enhanced by directivity. At the southern end of the Salton Sea, California earthquakes increase the gas flux at small mud volcanoes. Responses are best correlated with dynamic stresses. The comparison of responses in these nine settings indicates that dynamic stresses are most often correlated with triggering, although permanent stress changes as small as, and possibly smaller than, 0.1 bar may be sufficient to also influence eruptions. Unclamping stresses with magnitude similar to Earth tides (0.01 bar) persist over time and may play a role in triggering delayed responses. Unclamping stresses may be important contributors to short-term triggering only if they exceed 0.1-1 bar.

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

NASA Technical Reports Server (NTRS)

Cassinis, R.; Lechi, G. M.

1973-01-01

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.

Expert Systems for Real-Time Volcano Monitoring

NASA Astrophysics Data System (ADS)

Cassisi, C.; Cannavo, F.; Montalto, P.; Motta, P.; Schembra, G.; Aliotta, M. A.; Cannata, A.; Patanè, D.; Prestifilippo, M.

2014-12-01

In the last decade, the capability to monitor and quickly respond to remote detection of volcanic activity has been greatly improved through use of advanced techniques and semi-automatic software applications installed in most of the 24h control rooms devoted to volcanic surveillance. Ability to monitor volcanoes is being advanced by new technology, such as broad-band seismology, microphone networks mainly recording in the infrasonic frequency band, satellite observations of ground deformation, high quality video surveillance systems, also in infrared band, improved sensors for volcanic gas measurements, and advances in computer power and speed, leading to improvements in data transmission, data analysis and modeling techniques. One of the most critical point in the real-time monitoring chain is the evaluation of the volcano state from all the measurements. At the present, most of this task is delegated to one or more human experts in volcanology. Unfortunately, the volcano state assessment becomes harder if we observe that, due to the coupling of highly non-linear and complex volcanic dynamic processes, the measurable effects can show a rich range of different behaviors. Moreover, due to intrinsic uncertainties and possible failures in some recorded data, precise state assessment is usually not achievable. Hence, the volcano state needs to be expressed in probabilistic terms that take account of uncertainties. In the framework of the project PON SIGMA (Integrated Cloud-Sensor System for Advanced Multirisk Management) work, we have developed an expert system approach to estimate the ongoing volcano state from all the available measurements and with minimal human interaction. The approach is based on hidden markov model and deals with uncertainties and probabilities. We tested the proposed approach on data coming from the Mt. Etna (Italy) continuous monitoring networks for the period 2011-2013. Results show that this approach can be a valuable tool to aid the

Applications of geophysical methods to volcano monitoring

USGS Publications Warehouse

Wynn, Jeff; Dzurisin, Daniel; Finn, Carol A.; Kauahikaua, James P.; Lahusen, Richard G.

2006-01-01

The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even microphones tuned for infrasound. They include virtually every method used in resource exploration except large-scale seismic reflection. By “geophysical ” we include both active and passive methods as well as geodetic technologies. Volcano monitoring incorporates telemetry to handle high-bandwith cameras and broadband seismometers. Critical geophysical targets include the flux of magma in shallow reservoir and lava-tube systems, changes in active hydrothermal systems, volcanic edifice stability, and lahars. Since the eruption of Mount St. Helens in Washington State in 1980, and the eruption at Pu’u O’o in Hawai’i beginning in 1983 and still continuing, dramatic advances have occurred in monitoring technology such as “crisis GIS” and lahar modeling, InSAR interferograms, as well as gas emission geochemistry sampling, and hazards mapping and eruption predictions. The on-going eruption of Mount St. Helens has led to new monitoring technologies, including advances in broadband Wi-Fi and satellite telemetry as well as new instrumentation. Assessment of the gap between adequate monitoring and threat at the 169 potentially dangerous Holocene volcanoes shows where populations are dangerously exposed to volcanic catastrophes in the United States and its territories . This paper focuses primarily on Hawai’ian volcanoes and the northern Pacific and Cascades volcanoes. The US Geological Survey, the US National Park System, and the University of Utah cooperate in a program to monitor the huge Yellowstone volcanic system, and a separate observatory monitors the restive Long Valley

Volcano hazards program in the United States

USGS Publications Warehouse

Tilling, R.I.; Bailey, R.A.

1985-01-01

Volcano monitoring and volcanic-hazards studies have received greatly increased attention in the United States in the past few years. Before 1980, the Volcanic Hazards Program was primarily focused on the active volcanoes of Kilauea and Mauna Loa, Hawaii, which have been monitored continuously since 1912 by the Hawaiian Volcano Observatory. After the reawakening and catastrophic eruption of Mount St. Helens in 1980, the program was substantially expanded as the government and general public became aware of the potential for eruptions and associated hazards within the conterminous United States. Integrated components of the expanded program include: volcanic-hazards assessment; volcano monitoring; fundamental research; and, in concert with federal, state, and local authorities, emergency-response planning. In 1980 the David A. Johnston Cascades Volcano Observatory was established in Vancouver, Washington, to systematically monitor the continuing activity of Mount St. Helens, and to acquire baseline data for monitoring the other, presently quiescent, but potentially dangerous Cascade volcanoes in the Pacific Northwest. Since June 1980, all of the eruptions of Mount St. Helens have been predicted successfully on the basis of seismic and geodetic monitoring. The largest volcanic eruptions, but the least probable statistically, that pose a threat to western conterminous United States are those from the large Pleistocene-Holocene volcanic systems, such as Long Valley caldera (California) and Yellowstone caldera (Wyoming), which are underlain by large magma chambers still potentially capable of producing catastrophic caldera-forming eruptions. In order to become better prepared for possible future hazards associated with such historically unpecedented events, detailed studies of these, and similar, large volcanic systems should be intensified to gain better insight into caldera-forming processes and to recognize, if possible, the precursors of caldera-forming eruptions

A Volcano of Mud or Lava?

NASA Image and Video Library

2018-06-11

This image from NASA's Mars Reconnaissance Orbiter (MRO) shows a hill with a central crater. Such features have been interpreted as both mud volcanoes (really a sedimentary structure) and as actual volcanoes (the erupting lava kind). They occur on the floor of Valles Marineris below a closed topographic contour that could have held a lake, and the compaction of wet sediments may have created mud volcanoes. The fracture pattern of the bright flow unit surrounding the hill resembles mud cracks. However, there have also been observations from the CRISM instrument interpreted as high-temperature minerals, suggesting actual volcanism, although not necessarily at this location. Fine layers in the hill are consistent with either volcanism or mud flows. Either way, this activity is relatively recent in geologic time and may mark habitable subsurface environments. https://photojournal.jpl.nasa.gov/catalog/PIA22514

Swarms of small volcano-tectonic events preceding paroxysmal explosions of Tungurahua volcano (Ecuador)

NASA Astrophysics Data System (ADS)

Battaglia, J.; Hidalgo, S.; Douchain, J. M.; Pacheco, D. A.; Cordova, J.; Alvarado, A. P.; Parra, R.

2017-12-01

Tungurahua (5023 m a.s.l.) is an andesitic volcano located in Central Ecuador. It has been erupting since September 1999. It's activity transitioned in late 2008 towards the occurrence of distinct eruptive phases separated by periods of quiescence. These phases display a great variability of eruptive patterns. In particular the onsets of these phases are quite variable, ranging from progressive increase of surface activity to violent paroxysmal explosions eventually generating pyroclastic flows and plumes up to 13.000 m elevation. The volcano is monitored by the Instituto Geofisico in Quito whose permanent monitoring network include 6 broadband and 6 short period stations. These instruments record various signals related to eruptive processes as well as Long Period and volcano-tectonique (VT) events. However, most of the VT events are scattered around the volcano at depths up to 5-10 km b.s.l.. Their relationship with eruptive activity and precursory aspect are unclear. Since October 2013, we operate a temporary network of 13 broadband stations located up to 4275 m a.s.l., including on the Eastern flank which is remote. We examined data from a reference station located near the summit (3900 m a.s.l.) with a detection and classification procedure, searching for families of similar events. This processing enlights the presence of several families of small VTs previously poorly identified. We located manually some of these events and proceeded with similarity picking using cross-correlation and waveform similarity for nearly 400 events. Finally we applied precise relocation techniques. These events are located 2-3 km below the summit and define vertically elongated streaks. Their temporal evolution shows that they occur in swarms during the days or hours preceding the paroxysmal vent opening explosions in February and April 2014. These short-term precursors could indicate the rupturing of a barrier prior to the large explosions of Tungurahua.

Catalogue of Icelandic Volcanoes

NASA Astrophysics Data System (ADS)

Ilyinskaya, Evgenia; Larsen, Gudrún; Gudmundsson, Magnús T.; Vogfjörd, Kristin; Jonsson, Trausti; Oddsson, Björn; Reynisson, Vidir; Pagneux, Emmanuel; Barsotti, Sara; Karlsdóttir, Sigrún; Bergsveinsson, Sölvi; Oddsdóttir, Thorarna

2017-04-01

The Catalogue of Icelandic Volcanoes (CIV) is a newly developed open-access web resource (http://icelandicvolcanoes.is) intended to serve as an official source of information about volcanoes in Iceland for the public and decision makers. CIV contains text and graphic information on all 32 active volcanic systems in Iceland, as well as real-time data from monitoring systems in a format that enables non-specialists to understand the volcanic activity status. The CIV data portal contains scientific data on all eruptions since Eyjafjallajökull 2010 and is an unprecedented endeavour in making volcanological data open and easy to access. CIV forms a part of an integrated volcanic risk assessment project in Iceland GOSVÁ (commenced in 2012), as well as being part of the European Union funded effort FUTUREVOLC (2012-2016) on establishing an Icelandic volcano supersite. The supersite concept implies integration of space and ground based observations for improved monitoring and evaluation of volcanic hazards, and open data policy. This work is a collaboration of the Icelandic Meteorological Office, the Institute of Earth Sciences at the University of Iceland, and the Civil Protection Department of the National Commissioner of the Iceland Police, with contributions from a large number of specialists in Iceland and elsewhere.

Preliminary volcano-hazard assessment for the Katmai volcanic cluster, Alaska

USGS Publications Warehouse

Fierstein, Judy; Hildreth, Wes

2000-01-01

The world’s largest volcanic eruption of the 20th century broke out at Novarupta (fig. 1) in June 1912, filling with hot ash what came to be called the Valley of Ten Thousand Smokes and spreading downwind more fallout than all other historical Alaskan eruptions combined. Although almost all the magma vented at Novarupta, most of it had been stored beneath Mount Katmai 10 km away, which collapsed during the eruption. Airborne ash from the 3-day event blanketed all of southern Alaska, and its gritty fallout was reported as far away as Dawson, Ketchikan, and Puget Sound (fig. 21). Volcanic dust and sulfurous aerosol were detected within days over Wisconsin and Virginia; within 2 weeks over California, Europe, and North Africa; and in latter-day ice cores recently drilled on the Greenland ice cap. There were no aircraft in Alaska in 1912—fortunately! Corrosive acid aerosols damage aircraft, and ingestion of volcanic ash can cause abrupt jet-engine failure. Today, more than 200 flights a day transport 20,000 people and a fortune in cargo within range of dozens of restless volcanoes in the North Pacific. Air routes from the Far East to Europe and North America pass over and near Alaska, many flights refueling in Anchorage. Had this been so in 1912, every airport from Dillingham to Dawson and from Fairbanks to Seattle would have been enveloped in ash, leaving pilots no safe option but to turn back or find refuge at an Aleutian airstrip west of the ash cloud. Downwind dust and aerosol could have disrupted air traffic anywhere within a broad swath across Canada and the Midwest, perhaps even to the Atlantic coast. The great eruption of 1912 focused scientific attention on Novarupta, and subsequent research there has taught us much about the processes and hazards associated with such large explosive events (Fierstein and Hildreth, 1992). Moreover, work in the last decade has identified no fewer than 20 discrete volcanic vents within 15 km of Novarupta (Hildreth and others

Transition from phreatic to phreatomagmatic explosive activity of Zhupanovsky volcano (Kamchatka) in 2013-2016 due to volcanic cone collapse

NASA Astrophysics Data System (ADS)

Gorbach, Natalia; Plechova, Anastasiya; Portnyagin, Maxim

2017-04-01

Zhupanovsky volcano, situated 70 km north from Petropavlovsk-Kamchatsky city, resumed its activity in October 2013 [3]. In 2014 and in the first half of 2015, episodic explosions with ash plumes rising up to 6-8 km above sea level occurred on Priemish cone - one of four cones on the Zhupanovsky volcanic edifice [1]. In July 2015 after a series of seismic and explosive events, the southern sector of the active cone collapsed. The landslide and lahar deposits resulted from the collapse formed a large field on the volcano slopes [2]. In November 2015 and January-March 2016, a series of powerful explosions took place sending ash up to 8-10 km above sea level. No pure magmatic, effusive or extrusive, activity has been observed on Zhupanovsky in 2013-2016. We have studied the composition, morphology and textural features of ash particles produced by the largest explosive events of Zhupanovsky in the period from October 2013 to March 2016. The main components of the ash were found to be hydrothermally altered particles and lithics, likely originated by the defragmentation of rocks composing the volcanic edifice. Juvenile glass fragments occur in very subordinate quantities. The maximum amount of glass particles (up to 7%) was found in the ash erupted in January-March 2016, after the cone collapse. We suggest that the phreatic to phreatomagmatic explosive activity of Zhupanovsky volcano in 2013-2016 was initially caused by the intrusion of a new magma batch under the volcano. The intrusion and associated degassing of magma led to heating, overpressure and instability in the hydrothermal system of the volcano, causing episodic, predominantly phreatic explosions. Decompression of the shallow magmatic and hydrothermal system of the volcano due to the cone collapse in July 2015 facilitated a larger involvement of the magmatic component in the eruption and more powerful explosions. [1] Girina O.A. et al., 2016 Geophysical Research Abstracts Vol. 18, EGU2016-2101, doi: 10

Two magma bodies beneath the summit of Kīlauea Volcano unveiled by isotopically distinct melt deliveries from the mantle

NASA Astrophysics Data System (ADS)

Pietruszka, Aaron J.; Heaton, Daniel E.; Marske, Jared P.; Garcia, Michael O.

2015-03-01

The summit magma storage reservoir of Kīlauea Volcano is one of the most important components of the magmatic plumbing system of this frequently active basaltic shield-building volcano. Here we use new high-precision Pb isotopic analyses of Kīlauea summit lavas-from 1959 to the active Halema'uma'u lava lake-to infer the number, size, and interconnectedness of magma bodies within the volcano's summit reservoir. From 1971 to 1982, the 206Pb/204Pb ratios of the lavas define two separate magma mixing trends that correlate with differences in vent location and/or pre-eruptive magma temperature. These relationships, which contrast with a single magma mixing trend for lavas from 1959 to 1968, indicate that Kīlauea summit eruptions since at least 1971 were supplied from two distinct magma bodies. The locations of these magma bodies are inferred to coincide with two major deformation centers identified by geodetic monitoring of the volcano's summit region: (1) the main locus of the summit reservoir ∼2-4 km below the southern rim of Kīlauea Caldera and (2) a shallower magma body <2 km below the eastern rim of Halema'uma'u pit crater. Residence time modeling suggests that the total volume of magma within Kīlauea's summit reservoir during the late 20th century (1959-1982) was exceedingly small (∼0.1-0.5 km3). Voluminous Kīlauea eruptions, such as the ongoing, 32-yr old Pu'u 'Ō'ō rift eruption (>4 km3 of lava erupted), must therefore be sustained by a nearly continuous supply of new melt from the mantle. The model results show that a minimum of four compositionally distinct, mantle-derived magma batches were delivered to the volcano (at least three directly to the summit reservoir) since 1959. These melt inputs correlate with the initiation of energetic (1959 Kīlauea Iki) and/or sustained (1969-1974 Mauna Ulu, 1983-present Pu'u 'Ō'ō and 2008-present Halema'uma'u) eruptions. Thus, Kīlauea's eruptive behavior is partly tied to the delivery of new magma batches

Multidisciplinary Studies of the 2015-2016 Eruption of Momotombo Volcano, Nicaragua

NASA Astrophysics Data System (ADS)

Roman, D. C.; La Femina, P. C.; Connor, C.; Connor, L.; Dixon, T. H.; Feineman, M. D.; Gallant, E.; Geirsson, H.; Glover, C.; Rinehart, J. M.; Ruiz, G.; Saballos, A.; Strauch, W.; Tenorio, V.; Wauthier, C.; Webley, P. W.; Wnuk, K.

2016-12-01

Momotombo volcano, Nicaragua, began erupting in December 2015 after 105 years of dormancy. Within weeks of the eruption onset, an international team of scientists began interdisciplinary studies investigating the geophysical and geochemical processes of the eruption. Our work included the installation of new seismic and geodetic networks, sampling of lava flows and ashes for geochemical and petrographic analyses, and the collection and analysis of space and ground-based radar data. Momotombo volcano has been seismically restless since at least the 1980's, when modern records are first available. Beginning in September 2013, discrete seismic swarms including events up to M4 and depths of 20 km occurred periodically. On April 10, 2014 an M6.1 earthquake occurred in Lake Managua displacing the southern flank of the volcano more than 5 cm as measured at a continuous GPS (cGPS) site. A major seismic swarm, which included an M4.7 earthquake, began on November 24, 2015, and culminated in gas and ash eruptions beginning at 7:49 am (local time) on December 1, 2015. By the evening of December 1, Momotombo was in strombolian eruption with columns to 1 km and a lava flow advancing down the northern flank. To date, there have been over 435 explosions as detected by seismic data and visually on webcam imagery, with the last explosion on April 7, 2016. Utilizing cGPS and episodic GPS observations and radar interferometry (InSAR), we did not detect any significant pre-, co-, or post-eruptive magmatic deformation. Lava samples collected from the 2015, 1905, and pre-1905 eruptions are all basaltic andesites with nearly identical major and trace element compositions, suggesting a long-lived magma body. Concentrations of metals and volatiles in ash leachates decrease over time in the first two days of the eruption. Our interdisciplinary studies allow for an integrated analysis of this strombolian eruption and its hazards.

Tectono-Magmatic Cycles and Geodynamic Settings of Ore-Bearing System Formation in the Southern Cis-Argun Region

NASA Astrophysics Data System (ADS)

Petrov, V. A.; Andreeva, O. V.; Poluektov, V. V.; Kovalenko, D. V.

2017-11-01

The ore-bearing geological structural units of the southern Cis-Argun region are considered in the context of varying geodynamic regimes related to the Proterozoic, Caledonian, and Hercynian tectono-magmatic cycles, as well as during the Late Mesozoic within-plate tectono-magmatic activity, which give rise to the formation of subalkaline igneous rocks of the Shakhtama Complex with Au, Cu-Mo, Pb-Zn-Ag metallogenic specialization; volcano-plutonic complexes of calderas with Mo-U, Pb-Zn, and fluorite ores; and rare-metal granite of the Kukulbei Complex with a Sn-W-Li-Ta spectrum of mineralization. The comparative geochemical characteristics inherent to Mesozoic ore-bearing felsic igneous rocks are considered, as well as geodynamic settings of ore-bearing fluido-magmatic systems, taking into consideration new data on geochemistry of bimodal trachybasalt-trachydacite series and rhyolite of the Turga Series, which fill the Strel'tsovka Caldera, whose trend of evolution is defined as a reference for geological history of the studied territory. The geodynamic conditions, phase composition, and geochemistry of rocks along with metallogenic specialization of Mesozoic volcano-plutonic complexes of southern Cis-Argun region are close to those of the Great Khingan Belt in northeastern China and eastern Mongolia.

Alaska Volcano Observatory at 20

NASA Astrophysics Data System (ADS)

Eichelberger, J. C.

2008-12-01

The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the technical feasibility of keeping seismic stations operating through the long, dark, stormy Alaska winters. Some argued that AVO should simply cover Augustine with instruments and wait for the next eruption there, expected in the mid 90s (but delayed until 2006), rather than stretching to instrument as many volcanoes as possible. No sooner was AVO in place than Redoubt erupted and a fully loaded passenger 747 strayed into the eruption cloud between Anchorage and Fairbanks, causing a powerless glide to within a minute of impact before the pilot could restart two engines and limp into Anchorage. This event forcefully made the case that volcano hazard mitigation is not just about people and infrastructure on the ground, and is particularly important in the heavily traveled North Pacific where options for flight diversion are few. In 1996, new funding became available through an FAA earmark to aggressively extend volcano monitoring far into the Aleutian Islands with both ground-based networks and round-the-clock satellite monitoring. Beyond the Aleutians, AVO developed a monitoring partnership with Russians volcanologists at the Institute of Volcanology and Seismology in Petropavlovsk-Kamchatsky. The need to work together internationally on subduction phenomena that span borders led to formation of the Japan-Kamchatka-Alaska Subduction Processes (JKASP) consortium. JKASP meets approximately biennially in Sapporo, Petropavlovsk, and Fairbanks. In turn, these meetings and support from NSF and the Russian Academy of Sciences led to new international education and

Spying on volcanoes

NASA Astrophysics Data System (ADS)

Watson, Matthew

2017-07-01

Active volcanoes can be incredibly dangerous, especially to those who live nearby, but how do you get close enough to observe one in action? Matthew Watson explains how artificial drones are providing volcanologists with insights that could one day save human lives

Tracking the movement of Hawaiian volcanoes; Global Positioning System (GPS) measurement

USGS Publications Warehouse

Dvorak, J.J.

1992-01-01

At some well-studied volcanoes, surface movements of at least several centimeters take place out to distances of about 10 km from the summit of the volcano. Widespread deformation of this type is relatively easy to monitor, because the necessary survey stations can be placed at favorable sites some distance from the summit of the volcano. Examples of deformation of this type include Kilauea and Mauna Loa in Hawaii, Krafla in Iceland, Long Valley in California, Camp Flegrei in Italy, and Sakurajima in Japan. In contrast, surface movement at some other volcanoes, usually volcanoes with steep slopes, is restricted to places within about 1 km of their summits. Examples of this class of volcanoes include Mount St. Helens in Washington, Etna in Italy, and Tangkuban Parahu in Indonesia. Local movement on remote, rugged volcanoes of this type is difficult to observe using conventional methods of measuring ground movement, which generally require a clear line-of-sight between points of interest. However, a revolutionary new technique, called the Global Positional System (GPS), provides a very efficient, alternative method of making such measurements. GPS, which uses satellites and ground-based receivers to accurately record slight crustal movements, is rapidly becoming the method of choice to measure deformation at volcanoes. 

Geologic Map of the Summit Region of Kilauea Volcano, Hawaii

USGS Publications Warehouse

Neal, Christina A.; Lockwood, John P.

2003-01-01

This report consists of a large map sheet and a pamphlet. The map shows the geology, some photographs, description of map units, and correlation of map units. The pamphlet gives the full text about the geologic map. The area covered by this map includes parts of four U.S. Geological Survey 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water; the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones.

Nanoscale volcanoes: accretion of matter at ion-sculpted nanopores.

PubMed

Mitsui, Toshiyuki; Stein, Derek; Kim, Young-Rok; Hoogerheide, David; Golovchenko, J A

2006-01-27

We demonstrate the formation of nanoscale volcano-like structures induced by ion-beam irradiation of nanoscale pores in freestanding silicon nitride membranes. Accreted matter is delivered to the volcanoes from micrometer distances along the surface. Volcano formation accompanies nanopore shrinking and depends on geometrical factors and the presence of a conducting layer on the membrane's back surface. We argue that surface electric fields play an important role in accounting for the experimental observations.

Three dimensional volcano-acoustic source localization at Karymsky Volcano, Kamchatka, Russia

NASA Astrophysics Data System (ADS)

Rowell, Colin

We test two methods of 3-D acoustic source localization on volcanic explosions and small-scale jetting events at Karymsky Volcano, Kamchatka, Russia. Recent infrasound studies have provided evidence that volcanic jets produce low-frequency aerodynamic sound (jet noise) similar to that from man-made jet engines. Man-made jets are known to produce sound through turbulence along the jet axis, but discrimination of sources along the axis of a volcanic jet requires a network of sufficient topographic relief to attain resolution in the vertical dimension. At Karymsky Volcano, the topography of an eroded edifice adjacent to the active cone provided a platform for the atypical deployment of five infrasound sensors with intra-network relief of ˜600 m in July 2012. A novel 3-D inverse localization method, srcLoc, is tested and compared against a more common grid-search semblance technique. Simulations using synthetic signals indicate that srcLoc is capable of determining vertical source locations for this network configuration to within +/-150 m or better. However, srcLoc locations for explosions and jetting at Karymsky Volcano show a persistent overestimation of source elevation and underestimation of sound speed by an average of ˜330 m and 25 m/s, respectively. The semblance method is able to produce more realistic source locations by fixing the sound speed to expected values of 335 - 340 m/s. The consistency of location errors for both explosions and jetting activity over a wide range of wind and temperature conditions points to the influence of topography. Explosion waveforms exhibit amplitude relationships and waveform distortion strikingly similar to those theorized by modeling studies of wave diffraction around the crater rim. We suggest delay of signals and apparent elevated source locations are due to altered raypaths and/or crater diffraction effects. Our results suggest the influence of topography in the vent region must be accounted for when attempting 3-D

A New Statistical Model for Eruption Forecasting at Open Conduit Volcanoes: an Application to Mt Etna and Kilauea Volcanoes

NASA Astrophysics Data System (ADS)

Passarelli, Luigi; Sanso, Bruno; Laura, Sandri; Marzocchi, Warner

2010-05-01

One of the main goals in volcanology is to forecast volcanic eruptions. A trenchant forecast should be made before the onset of a volcanic eruption, using the data available at that time, with the aim of mitigating the volcanic risk associated to the volcanic event. In other words, models implemented with forecast purposes have to take into account the possibility to provide "forward" forecasts and should avoid the idea of a merely "retrospective" fitting of the data available. In this perspective, the main idea of the present model is to forecast the next volcanic eruption after the end of the last one, using only the data available at that time. We focus our attention on volcanoes with open conduit regime and high eruption frequency. We assume a generalization of the classical time predictable model to describe the eruptive behavior of open conduit volcanoes and we use a Bayesian hierarchical model to make probabilistic forecast. We apply the model to Kilauea volcano eruptive data and Mt. Etna volcano flank eruption data. The aims of this model are: 1) to test whether or not the Kilauea and Mt Etna volcanoes follow a time predictable behavior; 2) to discuss the volcanological implications of the time predictable model parameters inferred; 3) to compare the forecast capabilities of this model with other models present in literature. The results obtained using the MCMC sampling algorithm show that both volcanoes follow a time predictable behavior. The numerical values of the time predictable model parameters inferred suggest that the amount of the erupted volume could change the dynamics of the magma chamber refilling process during the repose period. The probability gain of this model compared with other models already present in literature is appreciably greater than zero. This means that our model performs better forecast than previous models and it could be used in a probabilistic volcanic hazard assessment scheme. In this perspective, the probability of

In Brief: U.S. Volcano Early Warning System; Bill provides clear mandate for NOAA

NASA Astrophysics Data System (ADS)

Showstack, Randy

2005-05-01

The U.S. Geological Survey on 29 April released a comprehensive review of the 169 U.S. volcanoes, and established a framework for a National Volcano Early Warning System that is being formulated by the Consortium of U.S. Volcano Observatories. The framework proposes an around-the-clock Volcano Watch Office and improved instrumentation and monitoring at targeted volcanoes. The report, authored by USGS scientists John Ewert, Marianne Guffanti, and Thomas Murray, notes that although a few U.S. volcanoes are well-monitored, half of the most threatening volcanoes are monitored at a basic level and some hazardous volcanoes have no ground-based monitoring.

Lava emplacements at Shiveluch volcano (Kamchatka) from June 2011 to September 2014 observed by TanDEM-X SAR-Interferometry

NASA Astrophysics Data System (ADS)

Heck, Alexandra; Kubanek, Julia; Westerhaus, Malte; Gottschämmer, Ellen; Heck, Bernhard; Wenzel, Friedemann

2016-04-01

As part of the Ring of Fire, Shiveluch volcano is one of the largest and most active volcanoes on Kamchatka Peninsula. During the Holocene, only the southern part of the Shiveluch massive was active. Since the last Plinian eruption in 1964, the activity of Shiveluch is characterized by periods of dome growth and explosive eruptions. The recent active phase began in 1999 and continues until today. Due to the special conditions at active volcanoes, such as smoke development, danger of explosions or lava flows, as well as poor weather conditions and inaccessible area, it is difficult to observe the interaction between dome growth, dome destruction, and explosive eruptions in regular intervals. Consequently, a reconstruction of the eruption processes is hardly possible, though important for a better understanding of the eruption mechanism as well as for hazard forecast and risk assessment. A new approach is provided by the bistatic radar data acquired by the TanDEM-X satellite mission. This mission is composed of two nearly identical satellites, TerraSAR-X and TanDEM-X, flying in a close helix formation. On one hand, the radar signals penetrate clouds and partially vegetation and snow considering the average wavelength of about 3.1 cm. On the other hand, in comparison with conventional InSAR methods, the bistatic radar mode has the advantage that there are no difficulties due to temporal decorrelation. By interferometric evaluation of the simultaneously recorded SAR images, it is possible to calculate high-resolution digital elevation models (DEMs) of Shiveluch volcano and its surroundings. Furthermore, the short recurrence interval of 11 days allows to generate time series of DEMs, with which finally volumetric changes of the dome and of lava flows can be determined, as well as lava effusion rates. Here, this method is used at Shiveluch volcano based on data acquired between June 2011 and September 2014. Although Shiveluch has a fissured topography with steep slopes

Large landslides from oceanic volcanoes

USGS Publications Warehouse

Holcomb, R.T.; Searle, R.C.

1991-01-01

Large landslides are ubiquitous around the submarine flanks of Hawaiian volcanoes, and GLORIA has also revealed large landslides offshore from Tristan da Cunha and El Hierro. On both of the latter islands, steep flanks formerly attributed to tilting or marine erosion have been reinterpreted as landslide headwalls mantled by younger lava flows. These landslides occur in a wide range of settings and probably represent only a small sample from a large population. They may explain the large volumes of archipelagic aprons and the stellate shapes of many oceanic volcanoes. Large landslides and associated tsunamis pose hazards to many islands. -from Authors

Imaging an Active Volcano Edifice at Tenerife Island, Spain

NASA Astrophysics Data System (ADS)

Ibáñez, Jesús M.; Rietbrock, Andreas; García-Yeguas, Araceli

2008-08-01

An active seismic experiment to study the internal structure of Teide volcano is being carried out on Tenerife, a volcanic island in Spain's Canary Islands archipelago. The main objective of the Tomography at Teide Volcano Spain (TOM-TEIDEVS) experiment, begun in January 2007, is to obtain a three-dimensional (3-D) structural image of Teide volcano using seismic tomography and seismic reflection/refraction imaging techniques. At present, knowledge of the deeper structure of Teide and Tenerife is very limited, with proposed structural models based mainly on sparse geophysical and geological data. The multinational experiment-involving institutes from Spain, the United Kingdom, Italy, Ireland, and Mexico-will generate a unique high-resolution structural image of the active volcano edifice and will further our understanding of volcanic processes.

Kilauea volcano eruption seen from orbit

NASA Technical Reports Server (NTRS)

1993-01-01

The STS-51 crew had a clear view of the erupting Kilauea volcano during the early morning pass over the Hawaiian islands. Kilauea, on the southwest side of the island of Hawaii, has been erupting almost continuously since January, 1983. Kilauea's summit caldera, with the smaller Halemaumau crater nestled within, is highlighted in the early morning sun (just above the center of the picture). The lava flows which covered roads and subdivisions in 1983-90 can be seen as dark flows to the east (toward the upper right) of the steam plumes on this photo. The summit crater and lava flows of Mauna Loa volcano make up the left side of the photo. Features like the Volcano House and Kilauea Visitor Center on the edge of the caldera, the small subdivisions east of the summit, Ola's Rain Forest north of the summit, and agricultural land along the coast are easily identified.

Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

PubMed

Kienle, J; Kowalik, Z; Murty, T S

1987-06-12

During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

Integration Of Low-Cost Single-Frequency GPS Stations Using 'Spider' Technology Within Existing Dual-Frequency GPS Network at Soufrière Hills Volcano, Montserrat (West Indies): Processing And Results

NASA Astrophysics Data System (ADS)

Pascal, K.; Palamartchouk, K.; Lahusen, R. G.; Young, K.; Voight, B.

2015-12-01

Twenty years ago, began the eruption of the explosive Soufrière Hills Volcano, dominating the southern part of the island of Montserrat, West Indies. Five phases of effusive activity have now occurred, characterized by dome building and collapse, causing numerous evacuations and the emigration of half of the population. Over the years, the volcano monitoring network has greatly expanded. The GPS network, started from few geodetic markers, now consists of 14 continuous dual frequency GPS stations, distributed on and around the edifice, where topography and vegetation allow. The continuous GPS time series have given invaluable insight into the volcano behavior, notably revealing deflation/inflation cycles corresponding to phases and pauses of effusive activity, respectively. In 2014, collaboration of the CALIPSO Project (Penn State; NSF) with the Montserrat Volcano Observatory enriched the GPS and seismic monitoring networks with six 'spider' stations. The 'spiders', developed by R. Lahusen at Cascades Volcano Observatory, are designed to be deployed easily in rough areas and combine a low cost seismic station and a L1-only GPS station. To date, three 'spiders' have been deployed on Soufrière Hills Volcano, the closest at ~1 km from the volcanic conduit, adjacent to a lava lobe on the dome. Here we present the details of GPS data processing in a network consisting of both dual and single frequency receivers ('spiders') using GAMIT/GLOBK software. Processing together single and dual frequency data allowed their representation in a common reference frame, and a meaningful geophysical interpretation of all the available data. We also present the 'spiders' time series along with the results from the rest of the network and examine if any significant deformation, correlating with other manifestations of volcanic activity, has been recorded by the 'spiders' since deployment. Our results demonstrate that low cost GNSS equipment can serve as valuable components in volcano

Renewed unrest at Mount Spurr Volcano, Alaska

USGS Publications Warehouse

Power, John A.

2004-01-01

The Alaska Volcano Observatory (AVO),a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc.This activity consists of increased seismicity melting of the summit ice cap, and substantial rates of C02 and H2S emission.The current unrest is centered beneath the volcano's 3374-m-high summit, whose last known eruption was 5000–6000 years ago. Since then, Crater Peak, 2309 m in elevation and 4 km to the south, has been the active vent. Recent eruptions occurred in 1953 and 1992.

Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

USGS Publications Warehouse

Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

2002-01-01

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G.The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes.Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001.This catalog includes: (1) earthquake origin times

Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

USGS Publications Warehouse

Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

2004-01-01

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003.The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003.This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a

Predicting the Timing and Location of the next Hawaiian Volcano

ERIC Educational Resources Information Center

Russo, Joseph; Mattox, Stephen; Kildau, Nicole

2010-01-01

The wealth of geologic data on Hawaiian volcanoes makes them ideal for study by middle school students. In this paper the authors use existing data on the age and location of Hawaiian volcanoes to predict the location of the next Hawaiian volcano and when it will begin to grow on the floor of the Pacific Ocean. An inquiry-based lesson is also…

Geologic field-trip guide to Medicine Lake Volcano, northern California, including Lava Beds National Monument

USGS Publications Warehouse

Donnelly-Nolan, Julie M.; Grove, Timothy L.

2017-08-17

Medicine Lake volcano is among the very best places in the United States to see and walk on a variety of well-exposed young lava flows that range in composition from basalt to rhyolite. This field-trip guide to the volcano and to Lava Beds National Monument, which occupies part of the north flank, directs visitors to a wide range of lava flow compositions and volcanic phenomena, many of them well exposed and Holocene in age. The writing of the guide was prompted by a field trip to the California Cascades Arc organized in conjunction with the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) quadrennial meeting in Portland, Oregon, in August of 2017. This report is one of a group of three guides describing the three major volcanic centers of the southern Cascades Volcanic Arc. The guides describing the Mount Shasta and Lassen Volcanic Center parts of the trip share an introduction, written as an overview to the IAVCEI field trip. However, this guide to Medicine Lake volcano has descriptions of many more stops than are included in the 2017 field trip. The 23 stops described here feature a range of compositions and volcanic phenomena. Many other stops are possible and some have been previously described, but these 23 have been selected to highlight the variety of volcanic phenomena at this rear-arc center, the range of compositions, and for the practical reason that they are readily accessible. Open ground cracks, various vent features, tuffs, lava-tube caves, evidence for glaciation, and lava flows that contain inclusions and show visible evidence of compositional zonation are described and visited along the route.

Real-Time Data Received from Mount Erebus Volcano, Antarctica

NASA Astrophysics Data System (ADS)

Aster, Richard; McIntosh, William; Kyle, Philip; Esser, Richard; Bartel, Beth Ann; Dunbar, Nelia; Johns, Bjorn; Johnson, Jeffrey B.; Karstens, Richard; Kurnik, Chuck; McGowan, Murray; McNamara, Sara; Meertens, Chuck; Pauley, Bruce; Richmond, Matt; Ruiz, Mario

2004-03-01

Internal and eruptive volcano processes involve complex interactions of multi-phase fluids with the solid Earth and the atmosphere, and produce diverse geochemical, visible, thermal, elastic, and anelastic effects. Multidisciplinary experimental agendas are increasingly being employed to meet the challenge of understanding active volcanoes and their hazards [e.g., Ripepe et al., 2002; Wallace et al., 2003]. Mount Erebus is a large (3794 m) stratovolcano that forms the centerpiece of Ross Island, Antarctica, the site of the principal U.S. (McMurdo) and New Zealand (Scott) Antarctic bases. With an elevation of 3794 m and a volume of ~1670 km3, Erebus offers exceptional opportunities for extended study of volcano processes because of its persistent, low-level, strombolian activity (Volcano Explosivity Index 0-1) and exposed summit magma reservoir (manifested as a long-lived phonolitic lava lake). Key scientific questions include linking conduit processes to near-field deformations [e.g., Aster et al., 2003], explosion physics [e.g., Johnson et al., 2003], magmatic differentiation and residence [e.g., Kyle et al., 1992], and effects on Antarctic atmospheric and ice geochemistry [e.g., Zreda-Gostynska et al., 1997]. The close proximity of Erebus (35 km) to McMurdo, and its characteristic dry, windy, cold, and high-elevation Antarctic environment, make the volcano a convenient test bed for the general development of volcano surveillance and other instrumentation under extreme conditions.

Magma supply, storage, and transport at shield-stage Hawaiian volcanoes: Chapter 5 in Characteristics of Hawaiian volcanoes

USGS Publications Warehouse

Poland, Michael P.; Miklius, Asta; Montgomery-Brown, Emily K.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

2014-01-01

Magma supply to Hawaiian volcanoes has varied over millions of years but is presently at a high level. Supply to Kīlauea’s shallow magmatic system averages about 0.1 km3/yr and fluctuates on timescales of months to years due to changes in pressure within the summit reservoir system, as well as in the volume of melt supplied by the source hot spot. Magma plumbing systems beneath Kīlauea and Mauna Loa are complex and are best constrained at Kīlauea. Multiple regions of magma storage characterize Kīlauea’s summit, and two pairs of rift zones, one providing a shallow magma pathway and the other forming a structural boundary within the volcano, radiate from the summit to carry magma to intrusion/eruption sites located nearby or tens of kilometers from the caldera. Whether or not magma is present within the deep rift zone, which extends beneath the structural rift zones at ~3-km depth to the base of the volcano at ~9-km depth, remains an open question, but we suggest that most magma entering Kīlauea must pass through the summit reservoir system before entering the rift zones. Mauna Loa’s summit magma storage system includes at least two interconnected reservoirs, with one centered beneath the south margin of the caldera and the other elongated along the axis of the caldera. Transport of magma within shield-stage Hawaiian volcanoes occurs through dikes that can evolve into long-lived pipe-like pathways. The ratio of eruptive to noneruptive dikes is large in Hawai‘i, compared to other basaltic volcanoes (in Iceland, for example), because Hawaiian dikes tend to be intruded with high driving pressures. Passive dike intrusions also occur, motivated at Kīlauea by rift opening in response to seaward slip of the volcano’s south flank.

Predicting and validating the motion of an ash cloud during the 2006 eruption of Mount Augustine volcano

USGS Publications Warehouse

Collins, Richard L.; Fochesatto, Javier; Sassen, Kenneth; Webley, Peter W.; Atkinson, David E.; Dean, Kenneson G.; Cahill, Catherine F.; Mizutani, Kohei

2007-01-01

On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20- year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash (or aerosol) cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. Aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano consistent with the Puff predictions. Two lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the ash cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be undetectable by any other means but are

Ice and water on Newberry Volcano, central Oregon

USGS Publications Warehouse

Donnelly-Nolan, Julie M.; Jensen, Robert A.; O'Connor, Jim; Madin, Ian P.; Dorsey, Rebecca

2009-01-01

Newberry Volcano in central Oregon is dry over much of its vast area, except for the lakes in the caldera and the single creek that drains them. Despite the lack of obvious glacial striations and well-formed glacial moraines, evidence indicates that Newberry was glaciated. Meter-sized foreign blocks, commonly with smoothed shapes, are found on cinder cones as far as 7 km from the caldera rim. These cones also show evidence of shaping by flowing ice. In addition, multiple dry channels likely cut by glacial meltwater are common features of the eastern and western flanks of the volcano. On the older eastern flank of the volcano, a complex depositional and erosional history is recorded by lava flows, some of which flowed down channels, and interbedded sediments of probable glacial origin. Postglacial lava flows have subsequently filled some of the channels cut into the sediments. The evidence suggests that Newberry Volcano has been subjected to multiple glaciations.

Volcanism offshore of Vesuvius Volcano in Naples Bay

USGS Publications Warehouse

Milia, A.; Mirabile, L.; Torrente, M.M.; Dvorak, J.J.

1998-01-01

High-resolution seismic reflection data are used to identify structural features in Naples Bay near Vesuvius Volcano. Several buried seismic units with reflection-free interiors are probably volcanic deposits erupted during and since the formation of the breached crater of Monte Somma Volcano, which preceded the growth of Vesuvius. The presumed undersea volcanic deposits are limited in extent; thus, stratigraphie relationships cannot be established among them. Other features revealed by our data include (a) the warping of lowstand marine deposits by undersea cryptodomes located approximately 10 km from the summit of Vesuvius, (b) a succession of normal step faults that record seaward collapse of the volcano, and (c) a small undersea slump in the uppermost marine deposits of Naples Bay, which may be the result of nue??e ardentes that entered the sea during a major eruption of Vesuvius in 1631. Detection of these undersea features illustrates some capabilities of making detailed seismic reflection profiles across undersea volcanoes.

Volcano-earthquake interaction at Mauna Loa volcano, Hawaii

NASA Astrophysics Data System (ADS)

Walter, Thomas R.; Amelung, Falk

2006-05-01

The activity at Mauna Loa volcano, Hawaii, is characterized by eruptive fissures that propagate into the Southwest Rift Zone (SWRZ) or into the Northeast Rift Zone (NERZ) and by large earthquakes at the basal decollement fault. In this paper we examine the historic eruption and earthquake catalogues, and we test the hypothesis that the events are interconnected in time and space. Earthquakes in the Kaoiki area occur in sequence with eruptions from the NERZ, and earthquakes in the Kona and Hilea areas occur in sequence with eruptions from the SWRZ. Using three-dimensional numerical models, we demonstrate that elastic stress transfer can explain the observed volcano-earthquake interaction. We examine stress changes due to typical intrusions and earthquakes. We find that intrusions change the Coulomb failure stress along the decollement fault so that NERZ intrusions encourage Kaoiki earthquakes and SWRZ intrusions encourage Kona and Hilea earthquakes. On the other hand, earthquakes decompress the magma chamber and unclamp part of the Mauna Loa rift zone, i.e., Kaoiki earthquakes encourage NERZ intrusions, whereas Kona and Hilea earthquakes encourage SWRZ intrusions. We discuss how changes of the static stress field affect the occurrence of earthquakes as well as the occurrence, location, and volume of dikes and of associated eruptions and also the lava composition and fumarolic activity.

Soufriere Hills Volcano

NASA Image and Video Library

2002-11-07

In this ASTER image of Soufriere Hills Volcano on Montserrat in the Caribbean, continued eruptive activity is evident by the extensive smoke and ash plume streaming towards the west-southwest. Significant eruptive activity began in 1995, forcing the authorities to evacuate more than 7,000 of the island's original population of 11,000. The primary risk now is to the northern part of the island and to the airport. Small rockfalls and pyroclastic flows (ash, rock and hot gases) are common at this time due to continued growth of the dome at the volcano's summit. This image was acquired on October 29, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. http://photojournal.jpl.nasa.gov/catalog/PIA03880

Volcano hazards at Fuego and Acatenango, Guatemala

USGS Publications Warehouse

Vallance, J.W.; Schilling, S.P.; Matías, O.; Rose, William I.; Howell, M.M.

2001-01-01

The Fuego-Acatenango massif comprises a string of five or more volcanic vents along a north-south trend that is perpendicular to that of the Central American arc in Guatemala. From north to south known centers of volcanism are Ancient Acatenango, Yepocapa, Pico Mayor de Acatenango, Meseta, and Fuego. Volcanism along the trend stretches back more than 200,000 years. Although many of the centers have been active contemporaneously, there is a general sequence of younger volcanism, from north to south along the trend. This massive volcano complex towers more than 3500 meters (m) above the Pacific coastal plain to the south and 2000 m above the Guatemalan Highlands to the north. The volcano complex comprises remnants of multiple eruptive centers, which periodically have collapsed to form huge debris avalanches. The largest of these avalanches extended more than 50 kilometers (km) from its source and covered more than 300 square km. The volcano has potential to produce huge debris avalanches that could inundate large areas of the Pacific coastal plain. In areas around the volcanoes and downslope toward the coastal plain, more than 100,000 people are potentially at risk from these and other flowage phenomena.

U.S. Geological Survey Volcano Hazards Program—Assess, forecast, prepare, engage

USGS Publications Warehouse

Stovall, Wendy K.; Wilkins, Aleeza M.; Mandeville, Charles W.; Driedger, Carolyn L.

2016-07-13

At least 170 volcanoes in 12 States and 2 territories have erupted in the past 12,000 years and have the potential to erupt again. Consequences of eruptions from U.S. volcanoes can extend far beyond the volcano’s immediate area. Many aspects of our daily life are vulnerable to volcano hazards, including air travel, regional power generation and transmission infrastructure, interstate transportation, port facilities, communications infrastructure, and public health. The U.S. Geological Survey has the Federal responsibility to issue timely warnings of potential volcanic activity to the affected populace and civil authorities. The Volcano Hazards Program (VHP) is funded to carry out that mission and does so through a combination of volcano monitoring, short-term warnings, research on how volcanoes work, and community education and outreach.

Kamchatka and North Kurile Volcano Explosive Eruptions in 2015 and Danger to Aviation

NASA Astrophysics Data System (ADS)

Girina, Olga; Melnikov, Dmitry; Manevich, Alexander; Demyanchuk, Yury; Nuzhdaev, Anton; Petrova, Elena

2016-04-01

There are 36 active volcanoes in the Kamchatka and North Kurile, and several of them are continuously active. In 2015, four of the Kamchatkan volcanoes (Sheveluch, Klyuchevskoy, Karymsky and Zhupanovsky) and two volcanoes of North Kurile (Alaid and Chikurachki) had strong and moderate explosive eruptions. Moderate gas-steam activity was observing of Bezymianny, Kizimen, Avachinsky, Koryaksky, Gorely, Mutnovsky and other volcanoes. Strong explosive eruptions of volcanoes are the most dangerous for aircraft because they can produce in a few hours or days to the atmosphere and the stratosphere till several cubic kilometers of volcanic ash and aerosols. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines. The eruptive activity of Sheveluch volcano began since 1980 (growth of the lava dome) and is continuing at present. Strong explosive events of the volcano occurred in 2015: on 07, 12, and 15 January, 01, 17, and 28 February, 04, 08, 16, 21-22, and 26 March, 07 and 12 April: ash plumes rose up to 7-12 km a.s.l. and extended more 900 km to the different directions of the volcano. Ashfalls occurred at Ust'-Kamchatsk on 16 March, and Klyuchi on 30 October. Strong and moderate hot avalanches from the lava dome were observing more often in the second half of the year. Aviation color code of Sheveluch was Orange during the year. Activity of the volcano was dangerous to international and local aviation. Explosive-effusive eruption of Klyuchevskoy volcano lasted from 01 January till 24 March. Strombolian explosive volcanic activity began from 01 January, and on 08-09 January a lava flow was detected at the Apakhonchich chute on the southeastern flank of the volcano. Vulcanian activity of the volcano began from 10 January. Ashfalls

Geomorphological classification of post-caldera volcanoes in the Buyan-Bratan caldera, North Bali, Indonesia

NASA Astrophysics Data System (ADS)

Okuno, Mitsuru; Harijoko, Agung; Wayan Warmada, I.; Watanabe, Koichiro; Nakamura, Toshio; Taguchi, Sachihiro; Kobayashi, Tetsuo

2017-12-01

A landform of the post-caldera volcanoes (Lesung, Tapak, Sengayang, Pohen, and Adeng) in the Buyan-Bratan caldera on the island of Bali, Indonesia can be classified by topographic interpretation. The Tapak volcano has three craters, aligned from north to south. Lava effused from the central crater has flowed downward to the northwest, separating the Tamblingan and Buyan Lakes. This lava also covers the tip of the lava flow from the Lesung volcano. Therefore, it is a product of the latest post-caldera volcano eruption. The Lesung volcano also has two craters, with a gully developing on the pyroclastic cone from the northern slope to the western slope. Lava from the south crater has flowed down the western flank, beyond the caldera rim. Lava distributed on the eastern side from the south also surrounds the Sengayang volcano. The Adeng volcano is surrounded by debris avalanche deposits from the Pohen volcano. Based on these topographic relationships, Sengayang volcano appears to be the oldest of the post-caldera volcanoes, followed by the Adeng, Pohen, Lesung, and Tapak volcanoes. Coarse-grained scoria falls around this area are intercalated with two foreign tephras: the Samalas tephra (1257 A.D.) from Lombok Island and the Penelokan tephra (ca. 5.5 kBP) from the Batur caldera. The source of these scoria falls is estimated to be either the Tapak or Lesung volcano, implying that at least two volcanoes have erupted during the Holocene period.

ASTER Images Mt. Usu Volcano

NASA Image and Video Library

2000-04-26

On April 3, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra Satellite captured this image of the erupting Mt. Usu volcano in Hokkaido, Japan. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image the Earth for the next 6 years to map and monitor the changing surface of our planet. This false color infrared image of Mt Usu volcano is dominated by Lake Toya, an ancient volcanic caldera. On the south shore is the active Usu volcano. On Friday, March 31, more than 11,000 people were evacuated by helicopter, truck and boat from the foot of Usu, that began erupting from the northwest flank, shooting debris and plumes of smoke streaked with blue lightning thousands of feet in the air. Although no lava gushed from the mountain, rocks and ash continued to fall after the eruption. The region was shaken by thousands of tremors before the eruption. People said they could taste grit from the ash that was spewed as high as 2,700 meters (8,850 ft) into the sky and fell to coat surrounding towns with ash. "Mount Usu has had seven significant eruptions that we know of, and at no time has it ended quickly with only a small scale eruption," said Yoshio Katsui, a professor at Hokkaido University. This was the seventh major eruption of Mount Usu in the past 300 years. Fifty people died when the volcano erupted in 1822, its worst known eruption. In the image, most of the land is covered by snow. Vegetation, appearing red in the false color composite, can be seen in the agricultural fields, and forests in the mountains. Mt. Usu is crossed by three dark streaks. These are the paths of ash deposits that rained out from eruption plumes two days earlier. The prevailing wind was from the northwest, carrying the ash away from the main city of Date. Ash deposited can be traced on the image as far away as 10 kilometers (16 miles

Major Martian Volcanoes from MOLA - Olympus Mons

NASA Technical Reports Server (NTRS)

2000-01-01

Two views of Olympus Mons, shown as topography draped over a Viking image mosaic. MOLA's regional topography has shown that this volcano sits off to the west of the main Tharsis rise rather than on its western flank. The topography also clearly shows the relationship between the volcano's scarp and massive aureole deposit that was produced by flank collapse. The vertical exaggeration is 10:1.

A Versatile Time-Lapse Camera System Developed by the Hawaiian Volcano Observatory for Use at Kilauea Volcano, Hawaii

USGS Publications Warehouse

Orr, Tim R.; Hoblitt, Richard P.

2008-01-01

Volcanoes can be difficult to study up close. Because it may be days, weeks, or even years between important events, direct observation is often impractical. In addition, volcanoes are often inaccessible due to their remote location and (or) harsh environmental conditions. An eruption adds another level of complexity to what already may be a difficult and dangerous situation. For these reasons, scientists at the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) have, for years, built camera systems to act as surrogate eyes. With the recent advances in digital-camera technology, these eyes are rapidly improving. One type of photographic monitoring involves the use of near-real-time network-enabled cameras installed at permanent sites (Hoblitt and others, in press). Time-lapse camera-systems, on the other hand, provide an inexpensive, easily transportable monitoring option that offers more versatility in site location. While time-lapse systems lack near-real-time capability, they provide higher image resolution and can be rapidly deployed in areas where the use of sophisticated telemetry required by the networked cameras systems is not practical. This report describes the latest generation (as of 2008) time-lapse camera system used by HVO for photograph acquisition in remote and hazardous sites on Kilauea Volcano.

Bi-directional volcano-earthquake interaction at Mauna Loa Volcano, Hawaii

NASA Astrophysics Data System (ADS)

Walter, T. R.; Amelung, F.

2004-12-01

At Mauna Loa volcano, Hawaii, large-magnitude earthquakes occur mostly at the west flank (Kona area), at the southeast flank (Hilea area), and at the east flank (Kaoiki area). Eruptions at Mauna Loa occur mostly at the summit region and along fissures at the southwest rift zone (SWRZ), or at the northeast rift zone (NERZ). Although historic earthquakes and eruptions at these zones appear to correlate in space and time, the mechanisms and implications of an eruption-earthquake interaction was not cleared. Our analysis of available factual data reveals the highly statistical significance of eruption-earthquake pairs, with a random probability of 5-to-15 percent. We clarify this correlation with the help of elastic stress-field models, where (i) we simulate earthquakes and calculate the resulting normal stress change at volcanic active zones of Mauna Loa, and (ii) we simulate intrusions in Mauna Loa and calculate the Coulomb stress change at the active fault zones. Our models suggest that Hilea earthquakes encourage dike intrusion in the SWRZ, Kona earthquakes encourage dike intrusion at the summit and in the SWRZ, and Kaoiki earthquakes encourage dike intrusion in the NERZ. Moreover, a dike in the SWRZ encourages earthquakes in the Hilea and Kona areas. A dike in the NERZ may encourage and discourage earthquakes in the Hilea and Kaoiki areas. The modeled stress change patterns coincide remarkably with the patterns of several historic eruption-earthquake pairs, clarifying the mechanisms of bi-directional volcano-earthquake interaction for Mauna Loa. The results imply that at Mauna Loa volcanic activity influences the timing and location of earthquakes, and that earthquakes influence the timing, location and the volume of eruptions. In combination with near real-time geodetic and seismic monitoring, these findings may improve volcano-tectonic risk assessment.

Volcano Deformation and Eruption Forecasting using Data Assimilation: Case of Grimsvötn volcano in Iceland

NASA Astrophysics Data System (ADS)

Bato, Mary Grace; Pinel, Virginie; Yan, Yajing

2016-04-01

The recent advances in Interferometric Synthetic Aperture Radar (InSAR) imaging and the increasing number of continuous Global Positioning System (GPS) networks recorded on volcanoes provide continuous and spatially extensive evolution of surface displacements during inter-eruptive periods. For basaltic volcanoes, these measurements combined with simple dynamical models (Lengliné et al. 2008 [1], Pinel et al, 2010 [2], Reverso et al, 2014 [3]) can be exploited to characterise and constrain parameters of one or several magmatic reservoirs using inversion methods. On the other hand, data assimilation-a time-stepping process that best combines models and observations, sometimes a priori information based on error statistics to predict the state of a dynamical system-has gained popularity in various fields of geoscience (e.g. ocean-weather forecasting, geomagnetism and natural resources exploration). In this work, we aim to first test the applicability and benefit of data assimilation, in particular the Ensemble Kalman Filter [4], in the field of volcanology. We predict the temporal behaviors of the overpressures and deformations by applying the two-magma chamber model of Reverso et. al., 2014 [3] and by using synthetic deformation data in order to establish our forecasting strategy. GPS time-series data of the recent eruptions at Grimsvötn volcano is used for the real case applicability of the method. [1] Lengliné, O., D Marsan, J Got, V. Pinel, V. Ferrazzini, P. Obuko, Seismicity and deformation induced by magma accumulation at three basaltic volcanoes, J. Geophys. Res., 113, B12305, 2008. [2] V. Pinel, C. Jaupart and F. Albino, On the relationship between cycles of eruptive activity and volcanic edifice growth, J. Volc. Geotherm. Res, 194, 150-164, 2010 [3] T. Reverso, J. Vandemeulebrouck, F. Jouanne, V. Pinel, T. Villemin, E. Sturkell, A two-magma chamber as a source of deformation at Grimsvötn volcano, Iceland, JGR, 2014 [4] Evensen, G., The Ensemble Kalman

Strategies for the implementation of a European Volcano Observations Research Infrastructure

NASA Astrophysics Data System (ADS)

Puglisi, Giuseppe

2015-04-01

Active volcanic areas in Europe constitute a direct threat to millions of people on both the continent and adjacent islands. Furthermore, eruptions of "European" volcanoes in overseas territories, such as in the West Indies, an in the Indian and Pacific oceans, can have a much broader impacts, outside Europe. Volcano Observatories (VO), which undertake volcano monitoring under governmental mandate and Volcanological Research Institutions (VRI; such as university departments, laboratories, etc.) manage networks on European volcanoes consisting of thousands of stations or sites where volcanological parameters are either continuously or periodically measured. These sites are equipped with instruments for geophysical (seismic, geodetic, gravimetric, electromagnetic), geochemical (volcanic plumes, fumaroles, groundwater, rivers, soils), environmental observations (e.g. meteorological and air quality parameters), including prototype deployment. VOs and VRIs also operate laboratories for sample analysis (rocks, gases, isotopes, etc.), near-real time analysis of space-borne data (SAR, thermal imagery, SO2 and ash), as well as high-performance computing centres; all providing high-quality information on the current status of European volcanoes and the geodynamic background of the surrounding areas. This large and high-quality deployment of monitoring systems, focused on a specific geophysical target (volcanoes), together with the wide volcanological phenomena of European volcanoes (which cover all the known volcano types) represent a unique opportunity to fundamentally improve the knowledge base of volcano behaviour. The existing arrangement of national infrastructures (i.e. VO and VRI) appears to be too fragmented to be considered as a unique distributed infrastructure. Therefore, the main effort planned in the framework of the EPOS-PP proposal is focused on the creation of services aimed at providing an improved and more efficient access to the volcanological facilities

Seismicity associated with magmatism, faulting and hydrothermal circulation at Aluto Volcano, Main Ethiopian Rift

NASA Astrophysics Data System (ADS)

Wilks, Matthew; Kendall, J.-Michael; Nowacki, Andy; Biggs, Juliet; Wookey, James; Birhanu, Yelebe; Ayele, Atalay; Bedada, Tulu

2017-06-01

The silicic volcanic centres of the Main Ethiopian Rift (MER) play a central role in facilitating continental rifting. Many of these volcanoes host geothermal resources and are located in heavily populated regions. InSAR studies have shown several are deforming, but regional seismic networks have detected little seismicity. A local network of 12 seismometers was deployed at Aluto Volcano from 2012 to 2014, and detected 2142 earthquakes within a 24-month period. We locate the events using a 1D velocity model that exploits a regional model and information from geothermal boreholes and calculate local magnitudes, b-values and focal mechanisms. Event depths generally range from the near surface to 15 km with most of the seismicity clustering in the upper 2 km. A significant amount of seismicity follows the Artu Jawa Fault Zone, which trends in alignment with the Wonji Fault Belt, NNE-SSW and is consistent with previous studies of strain localisation in the MER. Focal mechanisms are mostly normal in style, with the mean T-axes congruent to the orientation of extension in the rift at this latitude. Some show relatively small left-lateral strike-slip components and are likely associated with the reactivation of NE-ENE structures at the southern tip of the Aluto-Gedemsa segment. Events range from - 0.40 to 2.98 in magnitude and we calculate an overall b-value of 1.40 ± 0.14. This relatively elevated value suggests fluid-induced seismicity that is particularly evident in the shallow hydrothermal reservoir and above it. Subdividing our observations according to depth identifies distinct regions beneath the volcanic edifice: a shallow zone (- 2-0 km) of high seismicity and high b-values that corresponds to the hydrothermal system and is influenced by a high fluid saturation and circulation; a relatively aseismic zone (0-2 km) with low b-values that is impermeable to ascending volatiles; a region of increased fluid-induced seismicity (2-9 km) that is driven by magmatic

36 CFR 7.25 - Hawaii Volcanoes National Park.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Hawaii Volcanoes National Park. 7.25 Section 7.25 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.25 Hawaii Volcanoes National Park. (a...

36 CFR 7.25 - Hawaii Volcanoes National Park.