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Sample records for aso volcano japan

  1. Analysis of Fumarole Acoustics at Aso Volcano, Japan

    NASA Astrophysics Data System (ADS)

    McKee, K. F.; Yokoo, A.; Fee, D.; Huang, Y. C.; Yoshikawa, S.; Utsugi, M.; Minami, T.; Ohkura, T.

    2015-12-01

    The lowermost portion of large eruption columns is the momentum-driven, fluid flow portion known as a volcanic jet. The perturbation of the atmosphere from this region produces a sound known as jetting or jet noise. Recent work has shown that this volcanic jet noise produced by a volcano has similar characteristics as the sound from jet and rocket engines. The study of volcanic jet noise has gained much from laboratory jet engine studies; however, jet engines have been engineered to reduce noise thereby limiting their use as a comparison tool to the complex, ever-changing volcanic jet. Previous studies have noted that fumaroles produce jet noise without further detailed investigation. The goal of this work is to enhance our understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We aim to characterize the acoustic signature of fumaroles and evaluate if fumarolic jets scale to that of large volcanic jets. To investigate this, we deployed a 6-element acoustic array at two different locations along the edge of the crater wall at Aso Volcano, Japan from early July through mid-August 2015. Approximately two months before this deployment, the pyroclastic cone within Aso's crater partially collapsed into the vent. The cone was constructed during both ash venting and strombolian-style explosive activity in the last year. After the deployment, on July 13 a new small vent opened on the southwest flank of the pyroclastic cone. The vent is several meters in diameter and has consistent gas jetting which produces audible jet noise. To better capture the acoustic signature of the gas jetting we moved the array to the southwestern edge of the crater. The array is 230 meters from the vent and is positioned 54 degrees from the vertical jet axis, a recording angle usually not feasible in volcanic environments. Preliminary investigations suggest directionality at the source and the influence of topography along the propagation path as

  2. Coseismic rupturing stopped by Aso volcano during the 2016 Mw 7.1 Kumamoto earthquake, Japan.

    PubMed

    Lin, A; Satsukawa, T; Wang, M; Mohammadi Asl, Z; Fueta, R; Nakajima, F

    2016-11-18

    Field investigations and seismic data show that the 16 April 2016 moment magnitude (Mw) 7.1 Kumamoto earthquake produced a ~40-kilometer-long surface rupture zone along the northeast-southwest-striking Hinagu-Futagawa strike-slip fault zone and newly identified faults on the western side of Aso caldera, Kyushu Island, Japan. The coseismic surface ruptures cut Aso caldera, including two volcanic cones inside it, but terminate therein. The data show that northeastward propagation of coseismic rupturing terminated in Aso caldera because of the presence of magma beneath the Aso volcanic cluster. The seismogenic faults of the 2016 Kumamoto earthquake may require reassessment of the volcanic hazard in the vicinity of Aso volcano.

  3. Coseismic rupturing stopped by Aso volcano during the 2016 Mw 7.1 Kumamoto earthquake, Japan

    NASA Astrophysics Data System (ADS)

    Lin, A.; Satsukawa, T.; Wang, M.; Mohammadi Asl, Z.; Fueta, R.; Nakajima, F.

    2016-11-01

    Field investigations and seismic data show that the 16 April 2016 moment magnitude (Mw) 7.1 Kumamoto earthquake produced a ~40-kilometer-long surface rupture zone along the northeast-southwest-striking Hinagu-Futagawa strike-slip fault zone and newly identified faults on the western side of Aso caldera, Kyushu Island, Japan. The coseismic surface ruptures cut Aso caldera, including two volcanic cones inside it, but terminate therein. The data show that northeastward propagation of coseismic rupturing terminated in Aso caldera because of the presence of magma beneath the Aso volcanic cluster. The seismogenic faults of the 2016 Kumamoto earthquake may require reassessment of the volcanic hazard in the vicinity of Aso volcano.

  4. Source properties of Strombolian explosions at Aso volcano, Japan, derived from seismic signals

    NASA Astrophysics Data System (ADS)

    Zobin, Vyacheslav M.; Sudo, Yasuaki

    2017-07-01

    A new episode of Strombolian activity at Aso volcano, Japan began on 25 November 2014, causing ashfall and glowing emissions. A total of 100 seismic signals of explosive events, recorded during November 2014 to February 2015 by a short-period seismic station that was situated at a distance of 150 m from the crater, were investigated. They indicated a two-phase structure of the seismic waveforms. The seismic signals consisted of the initial phase of lower frequency and lower amplitude and the main phase of higher frequency and higher amplitude that allowed to propose a two-stage conceptual model of Strombolian explosions at Aso volcano. According to the model, the initial phase is generated by the vertical movement of the gas slug in the volcanic conduit before an explosion, and the main phase is generated by the subsequent explosion. In the framework of this model, the following seismic parameters of Strombolian Aso explosions were calculated: the power of the initial seismic phases as a measure of force governing the gas-slug movement to the surface, and the power of the main seismic phases as a measure of the energy of the eruption. Direct log-log dependence of the power of the main phase of the seismic signals on the power of initial seismic phases, obtained in the paper, indicates the dependence of the eruption energy on the magnitude of the force governing the movement of the gas slug before an explosion.

  5. Analysis of gas jetting and fumarole acoustics at Aso Volcano, Japan

    NASA Astrophysics Data System (ADS)

    McKee, Kathleen; Fee, David; Yokoo, Akihiko; Matoza, Robin S.; Kim, Keehoon

    2017-06-01

    The gas-thrust region of a large volcanic eruption column is predominately a momentum-driven, fluid flow process that perturbs the atmosphere and produces sound akin to noise from jet and rocket engines, termed ;jet noise;. We aim to enhance understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We characterize the acoustic signature of 2.5-meter wide vigorously jetting fumarole at Aso Volcano, Japan using a 5-element infrasound array located on the nearby crater. The fumarole opened on 13 July 2015 on the southwest flank of the partially collapsed pyroclastic cone within Aso Volcano's Naka-dake crater and had persistent gas jetting, which produced significant audible jet noise. The array was 220 m from the fumarole and 57.6° from the vertical jet axis, a recording angle not typically feasible in volcanic environments. Array processing is performed to distinguish fumarolic jet noise from wind. Highly correlated periods are characterized by sustained, low-amplitude signal with a 7-10 Hz spectral peak. Finite difference time domain method numerical modeling suggests the influence of topography near the vent and along the propagation path significantly affects the spectral content, complicating comparisons with laboratory jet noise. The fumarolic jet has a low estimated Mach number (0.3 to 0.4) and measured temperature of 260 °C. The Strouhal number for infrasound from volcanic jet flows and geysers is not known; thus we assume a peak Strouhal number of 0.19 based on pure-air laboratory jet experiments. This assumption leads to an estimated exit velocity of the fumarole of 79 to 132 m/s. Using published gas composition data from 2003 to 2009, the fumarolic vent area estimated from thermal infrared images, and estimated jet velocity, we estimate total volatile flux at 160-270 kg/s (14,000-23,000 t/d).

  6. Origin and mode of emplacement of lithic-rich breccias at Aso Volcano, Japan: Geological, paleomagnetic, and petrological reconstruction

    NASA Astrophysics Data System (ADS)

    Furukawa, Kuniyuki; Uno, Koji; Shinmura, Taro; Miyoshi, Masaya; Kanamaru, Tatsuo; Inokuchi, Hiroo

    2014-04-01

    Takajosan breccia rocks are distributed around the southwestern caldera rim of the Aso Volcano in Japan. They are characterized by coarse lithic breccias with a pumiceous matrix. The proximal coarse lithic breccias are divided into the lower massive unit and the upper stratified unit. The lower massive lithic breccias tend to transform laterally into tuff breccias and pumiceous lapilli tuffs. Paleomagnetic results showed that all of the deposits were deposited at high temperatures of 175-560 °C. This was also supported by geological characteristics such as spatter clasts, clasts with a bread-crust texture, and weakly welded parts. These features clearly show that the deposits originated from pyroclastic density currents (PDCs). The dense lithic-rich lithofacies, low vesicularity of pumice, lack of plinian fall deposits, and radial distribution indicate that the deposits were derived from boil-over PDCs rather than plinian column-collapse PDCs. The SiO2 contents of the matrix glasses of the proximal lower massive breccia showed a progressive decrease from the bottom toward the upper part. We interpret that this chemical variation corresponds to chemical zonation of the magma chamber. This indicates that the massive deposits aggraded progressively from the base upwards (progressive aggradation), rather than through en masse freezing. The vertical lithofacies changes of the proximal breccias from the lower massive to the upper stratified units indicate that a sustained current in a quasi-steady state switched to an unsteady current with the progression of the volcanic activity.

  7. Origin and deformation of high porosity bands in the Takanoobane Rhyolite lava of Aso volcano, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.

    2015-10-01

    In rhyolite lavas, the high porosity bands are often developed. They potentially act as pathways for gas movement to the lava surface. Since explosive activities of lavas are generally considered to be controlled by degassing system, understanding the origin and deformation process of the high porosity bands is important to assessing volcanic hazards. The Takanoobane rhyolite lava in the middle of Kyushu Island in SW Japan is effused at 51 ± 5 ka. The volume, flow length, and thickness are 0.14 km3, > 2 km, and about 90 m, respectively. The central crystalline part of the lava is characterized by the light-colored bands defined by the high porosity zone (HPZ). On the basis of geological and petrographical studies, we revealed that the HPZ was primary formed by ductile-brittle tearing of the lava (known as cavitation). According to the AMS results, the HPZs were subsequently stretched and flattened laterally during the concentric spreading of the lava. This deformation process could stretch the HPZ not only radially but also laterally. This effective stretching developed the HPZ into pervasive thin bands. Since the HPZs act as degassing pathways to the lava surface, the pervasive HPZ bands may play a role in providing volcanic gasses to void spaces created in surface fold hinges of rhyolite lavas. Thus, this degassing system may promote explosive activity of the lava surface.

  8. Fracturing during ductile-brittle transition and development of flow banding in the Takanoobane Rhyolite lava of Aso volcano, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.

    2014-12-01

    Flow banding, which is characterized by deformation of highly vesicular part, is ubiquitously observed in rhyolite lavas. To explore the origin of the highly vesicular part, we examined Takanoobane rhyolite lava (TR lava) in Aso caldera, Japan, which effused at 51+/-5 ka (Matsumoto et al., 1991). The highly vesicular parts characterized by ductile deformation are well developed in the central crystalline layer, at which the parts tend to be flattened with an increasing of distance from the source. The part develops into flow bands. The highly vesicular parts are also recognized around fractures that developed perpendicular to the flow direction, and adjacent to phenocrysts. The highly vesicular part is composed of cavities with mainly <100 μm in diameter. Microscopic observation and the SEM image show that the cavities have ragged walls characterized by the protrusion of groundmass crystals and phenocrysts. Smith et al. (2001) described such cavities in detail using three silicic lavas in Japan, and proposed that the cavities were formed by failure of the magma by flow during ductile-brittle transition. The authors described the fracturing mechanism as cavitation, and considered that groundmass adjacent to phenocryst also appears to act as a site of strong cavitation because of the steep strain gradient between deforming matrix and non-deforming phenocrysts. The similarity of the textures means that the highly vesicular part in TR lava was also formed by cavitation during ductile-brittle transition. The part would be deformed and flattened with progression of lava deformation. We analyzed the anisotropy of magnetic susceptibility (AMS) to estimate the deformation style of TR lava. The results show that the highly vesicular part was deformed by pure shear strain. We established the following model for the development of flow banding. In TR lava, the highly vesicular parts were formed by failure of the magma during ductile-brittle transition during and/or after lava

  9. Collateral variations between the concentrations of mercury and other water soluble ions in volcanic ash samples and volcanic activity during the 2014-2016 eruptive episodes at Aso volcano, Japan

    NASA Astrophysics Data System (ADS)

    Marumoto, Kohji; Sudo, Yasuaki; Nagamatsu, Yoshizumi

    2017-07-01

    During 2014-2016, the Aso volcano, located in the center of the Kyushu Islands, Japan, erupted and emitted large amounts of volcanic gases and ash. Two episodes of the eruption were observed; firstly Strombolian magmatic eruptive episodes from 25 November 2014 to the middle of May 2015, and secondly phreatomagmatic and phreatic eruptive episodes from September 2015 to February 2016. Bulk chemical analyses on total mercury (Hg) and major ions in water soluble fraction in volcanic ash fall samples were conducted. During the Strombolian magmatic eruptive episodes, total Hg concentrations averaged 1.69 ± 0.87 ng g- 1 (N = 33), with a range from 0.47 to 3.8 ng g- 1. In addition, the temporal variation of total Hg concentrations in volcanic ash varied with the amplitude change of seismic signals. In the Aso volcano, the volcanic tremors are always observed during eruptive stages and quiet interludes, and the amplitudes of tremors increase at eruptive stages. So, the temporal variation of total Hg concentrations could provide an indication of the level of volcanic activity. During the phreatomagmatic and phreatic eruptive episodes, on the other hand, total Hg concentrations in the volcanic ash fall samples averaged 220 ± 88 ng g- 1 (N = 5), corresponding to 100 times higher than those during the Strombolian eruptive episode. Therefore, it is possible that total Hg concentrations in volcanic ash samples are largely varied depending on the eruptive type. In addition, the ash fall amounts were also largely different among the two eruptive episodes. This can be also one of the factors controlling Hg concentrations in volcanic ash.

  10. Diverse long Period tremors and their implications on degassing and heating inside Aso volcano

    NASA Astrophysics Data System (ADS)

    Niu, Jieming; Song, Teh-Ru Alex

    2017-04-01

    Long-period tremors (LPTs) are frequently observed and documented in many active volcanoes around the world, Typically, LPTs are in the period range of 2-100 seconds and total duration of 300 seconds or less. In many instances, LPTs in different volcanic settings are repetitive, but time-invariant in their location, frequency content and waveform shape, suggesting a nondestructive source and providing critical insights into the fluid-dynamic processes operating inside a volcanic system. However, the diversities of LPTs in a single volcanic system are not necessarily well understood and they could potentially provide a clue on the interplay between volcanic degassing, magmatic heating and the style of upcoming eruption. To explore possible diverse LPT behavior in a volcanic system, we investigate LPTs in Aso-san, one of the most well studied and active volcanoes in the southwest Kyushu, Japan. We carry out systematic analysis of continuous seismic data (2010-2016) operated at V-net by NIED and Japan Meterogeolgical Agency (JMA) Volcanic Seismic Network, covering the interval where Aso-san experiences diverse behaviors, including long period of quiescence (2010-2013), phreatic eruption (2013-2014), Strombolian-type eruption (2014-2015) and phreatomagmatic eruption (2016). We use LPT waveforms identified in previous studies as templates and cross-correlate them against the entire dataset in the wavelet domain to construct LPTs catalog. However, LPTs with different phase, but similar frequency content and location are also retained to examine possible temporal changes in the characteristics of LPTs. Through waveform cross-correlation and stacking, we identify four types of LPTs that are located in close proximity as those identified in prior studies, but they display diverse waveform polarity and shape. We will present waveform semblance analysis and moment tensor inversion of these LPTs and discuss how their frequency, amplitude and energetics may be indicative of the

  11. Volcanic magma reservoir imaged as a low-density body beneath Aso volcano that terminated the 2016 Kumamoto earthquake rupture

    NASA Astrophysics Data System (ADS)

    Miyakawa, Ayumu; Sumita, Tatsuya; Okubo, Yasukuni; Okuwaki, Ryo; Otsubo, Makoto; Uesawa, Shimpei; Yagi, Yuji

    2016-12-01

    We resolve the density structure of a possible magma reservoir beneath Aso, an active volcano on Kyushu Island, Japan, by inverting gravity data. In the context of the resolved structure, we discuss the relationship between the fault rupture of the 2016 Kumamoto earthquake and Aso volcano. Low-density bodies were resolved beneath central Aso volcano using a three-dimensional inversion with an assumed density contrast of ±0.3 g/cm3. The resultant location of the southern low-density body is consistent with a magma reservoir reported in previous studies. No Kumamoto aftershocks occur in the southern low-density body; this aseismic anomaly may indicate a ductile feature due to high temperatures and/or the presence of partial melt. Comparisons of the location of the southern low-density body with rupture models of the mainshock, obtained from teleseismic waveform and InSAR data, suggest that the rupture terminus overlaps the southern low-density body. The ductile features of a magma reservoir could have terminated rupture propagation. On the other hand, a northern low-density body is resolved in the Asodani area, where evidence of current volcanic activity is scarce and aftershock activity is high. The northern low-density body might, therefore, be derived from a thick caldera fill in the Asodani area, or correspond to mush magma or a high-crystallinity magma reservoir that could be the remnant of an ancient intrusion.[Figure not available: see fulltext.

  12. Magma plumbing system at the beginning of repeated caldera eruption: A case study on Aso-1 erupted about 270 ky ago from Aso caldera, SW Japan

    NASA Astrophysics Data System (ADS)

    Miyagi, I.; Hoshizumi, H.; Miyabuchi, Y.

    2015-12-01

    In order to understand the commencement of magma plumbing system of a polygenetic caldera, we started petrological study on the earliest eruptive product of Aso caldera, SW Japan. Aso caldera is one of the active volcano in Japan which have produced four stages (Aso-1, -2, -3, -4) of large-scale pyroclastic flow deposits 270 to 90 ky. ago. A suite of samples were collected from the bottom of Aso-1 pyroclastic flow deposit and from the underlying tephra layer (Ono et al., 1979). The tephra comprises more than 10 pumice fall units inter-layered by dark gray volcanic ash. For whole rock chemistry, coarser pumice fragments were separated. For mineral and glass chemistry, phenocrysts and glass particles were handpicked from the sieved 500-1000 um fractions under a binocular microscope. This fraction consist of plagioclase, orthopyroxene, variably vesiculated volcanic glass fragments, and clinopyroxene phenocrysts. They were analyzed using an electron micro-probe. The suite of samples are similar and major temporal change is the chemical composition of orthopyroxenes; those from upper horizon are relatively Mg rich. Anorthite content of plagioclase phenocryst is bimodal 49-53 mol. % (major) and 57-70 mol. % (minor). Silica content of matrix glass fall in a narrow range 68-70 wt. %. Temperature and oxygen fugacity were estimated to be 865-905 deg-C and FMQ+2 log unit, respectively, using ILMAT (Lepage, 2003). Pressure and water content of the magma are estimated to be 5-7 kbar and 0.5-1 wt. % H2O, respectively, using rhyolite-MELTS (Gualda et al., 2012) on the most undifferentiated tholeiitic basalt of Aso 4KC-03 (Hunter, 1998) to reproduce the observed composition of matrix glass (68-70 wt. % SiO2) and plagioclase (An 49-53 mol. %). The calcic plagioclase (An 57-70 mol. %), however, suggest that the basalt was initially hydrous and require magma degassing before the differentiation. If we assume degassing by magma convection in a conduit (Kazahaya et al., 1994), the

  13. Unzen Volcano, Japan

    NASA Image and Video Library

    1996-11-13

    This is a space radar image of the area around the Unzen volcano, on the west coast of Kyushu Island in southwestern Japan. Unzen, which appears in this image as a large triangular peak with a white flank near the center of the peninsula, has been continuously active since a series of powerful eruptions began in 1991. 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 93rd orbit on April 15, 1994. The image shows an area 41.5 kilometers by 32.8 kilometers (25.7 miles by 20.3 miles) that is centered at 32.75 degrees north latitude and 130.15 degrees east longitude. North is toward the upper left of the image. The radar illumination is from the top of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (vertically transmitted and received); green represents the average of L-band and C-band (vertically transmitted and received); blue represents the C-band (vertically transmitted and received). Unzen is one of 15 "Decade" volcanoes identified by the scientific community as posing significant potential threats to large local populations. The city of Shimabara sits along the coast at the foot of Unzen on its east and northeast sides. At the summit of Unzen a dome of thick lava has been growing continuously since 1991. Collapses of the sides of this dome have generated deadly avalanches of hot gas and rock known as pyroclastic flows. Volcanologists can use radar image data to monitor the growth of lava domes, to better understand and predict potentially hazardous collapses. http://photojournal.jpl.nasa.gov/catalog/PIA00504

  14. Unzen Volcano, Japan

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This is a space radar image of the area around the Unzen volcano, on the west coast of Kyushu Island in southwestern Japan. Unzen, which appears in this image as a large triangular peak with a white flank near the center of the peninsula, has been continuously active since a series of powerful eruptions began in 1991. 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 93rd orbit on April 15, 1994. The image shows an area 41.5 kilometers by 32.8 kilometers (25.7 miles by 20.3 miles) that is centered at 32.75 degrees north latitude and 130.15 degrees east longitude. North is toward the upper left of the image. The radar illumination is from the top of the image. The colors in this image were obtained using the following radar channels: red represents the L-band (vertically transmitted and received); green represents the average of L-band and C-band (vertically transmitted and received); blue represents the C-band (vertically transmitted and received). Unzen is one of 15 'Decade' volcanoes identified by the scientific community as posing significant potential threats to large local populations. The city of Shimabara sits along the coast at the foot of Unzen on its east and northeast sides. At the summit of Unzen a dome of thick lava has been growing continuously since 1991. Collapses of the sides of this dome have generated deadly avalanches of hot gas and rock known as pyroclastic flows. Volcanologists can use radar image data to monitor the growth of lava domes, to better understand and predict potentially hazardous collapses.

    Spaceborne Imaging Radar-C and X-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: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The

  15. Nekodake stratovolcano formed at the edge of caldera before the huge pyroclastic eruptions of Aso, Japan: petrological constraints on magma supply system

    NASA Astrophysics Data System (ADS)

    Ueda, Y.; Hasenaka, T.; Mori, Y.

    2011-12-01

    Volcanic activities prior to caldera-forming eruptions give important constraints on the magma supply system leading to catastrophic eruptions. Nekodake volcano located in the eastern end of Aso Caldera, Central Kyushu, Japan, was considered to have been active during the post-caldera period. However, the stratigraphic relations and radiometric ages suggest that the Nekodake volcano was active during the caldera forming periods, Aso-1, Aso-2, Aso-3 and Aso-4 pyroclastic flows. In the history of the activities of the Aso volcano, there are some parasitic eruptive activities between pyroclastic flows. However, the relationship between those activities and the pyroclastic flow eruptions is not clear. The purpose of this study is to clarify the petrological relation between magmas of the Nekodake volcano and those of Aso pyroclastic flows. We investigated geological features of the Nekodake volcano, and conducted whole rock chemical analysis and the petrographical description of the volcanic products of Nekodake. We classified the Nekodake volcanic products into four groups from phenocryst assemblage, and two groups from the chemical composition. We found a correlation between petrographical groups and compositional groups. For example, incompatible elements are abundant in olivine group (olivine + 2 pyroxene + plagioclases). Nekodake volcanic products and the caldera-forming products show contrasting differentiation trends on the Harker diagrams. MgO, Al2O3, and CaO contents are high and TiO2, P2O5, and Fe2O3 are low in Nekodake products compared with those in caldera-forming products. Incompatible elements of Nekodake volcanic products show characteristically lower values (K20:0. 6 wt.% - 1.5 wt.%, Rb: 14.2 - 50.0 ppm, Zr: 90.7 ppm -129.2 ppm) than those of caldera-forming products (K20: 1.2 wt.%- 5.0 wt.%, Rb: 21.2 - 165.0 ppm, Zr: 93.76 ppm -321.0 ppm). These data show that the magma reservoir of Nekodake volcano and that of the gigantic pyroclastic eruptions are

  16. Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan

    NASA Astrophysics Data System (ADS)

    Nobile, Adriano; Acocella, Valerio; Ruch, Joel; Aoki, Yosuke; Borgstrom, Sven; Siniscalchi, Valeria; Geshi, Nobuo

    2017-05-01

    The relation between unrest and eruption at calderas is still poorly understood. Aso caldera, Japan, shows minor episodic phreatomagmatic eruptions associated with steady subsidence. We analyse the deformation of Aso using SAR images from 1993 to 2011 and compare it with the eruptive activity. Although the dataset suffers from limitations (e.g. atmospheric effects, coherence loss, low signal-to-noise ratio), we observe a steady subsidence signal from 1996 to 1998, which suggests an overall contraction of a magmatic source below the caldera centre, from 4 to 5 km depth. We propose that the observed contraction may have been induced by the release of the magmatic fluids feeding the eruptions. If confirmed by further data, this hypothesis suggests that degassing processes play a crucial role in triggering minor eruptions within open conduit calderas, such as at Aso. Our study underlines the importance of defining any eruptive potential also from deflating magmatic systems with open conduit.

  17. Exploration and monitoring geothermal activity using Landsat ETM + images. A case study at Aso volcanic area in Japan

    NASA Astrophysics Data System (ADS)

    Mia, Md. Bodruddoza; Nishijima, Jun; Fujimitsu, Yasuhiro

    2014-04-01

    Thermal activity monitoring in and around active volcanic areas using remote sensing is an essential part of volcanology nowadays. Three identical approaches were used for thermal activity exploration at Aso volcanic area in Japan using Landsat ETM + images. First, the conventional methods for hydrothermal alteration mapping were applied to find the most active thermal region after exploring geothermal indicator minerals. Second, we found some thermally highly anomalous regions around Nakadake crater using land surface temperature estimation. Then, the Stefan-Boltzmann equation was used for estimating and also monitoring radiative heat flux (RHF) from the most active region of about 8 km2 in and around Nakadake crater in the central part of the Aso volcano. To fulfill the required parameter in the Stefan-Boltzmann equation for radiative heat flux, the NDVI (Normalized differential vegetation index) method was used for spectral emissivity, and the mono-window algorithm was used for land surface temperature of this study area. The NDVI value was used to divide land-cover in the study area into four types: water, bare ground, mixed and vegetated land. The bare land was found within the most active region. Vegetation coverage area showed an inverse relationship with total RHF in this study as health of thermally stressed vegetation supports this relationship. The spatial distribution of spectral emissivity ranged from 0.94 to 0.99 in our study. Land surface temperature was estimated using a mono-window algorithm and was highest LST in 2008 and lowest in 2011. The results of RHF showed that the highest pixel RHF was found to be about 296 W/m2 in 2008. Total RHF was obtained of about 607 MW in 2002 and the lowest was about 354 MW in 2008. The RHF anomaly area was found the highest in 2002 and was lowest in 2011. The highest total heat discharge rate (HDR) obtained about 3918 MW in 2002 and lowest total HDR about 2289 MW in 2008 from this study area. But in the case of

  18. Steady subsidence of a repeatedly erupting caldera through InSAR observations: Aso, Japan

    NASA Astrophysics Data System (ADS)

    Nobile, Adriano; Acocella, Valerio; Aoki, Yosuke; Ruch, Joël; Borgstrom, Sven; Siniscalchi, Valeria; Geshi, Nobuo

    2017-04-01

    The relation between unrest and eruption at calderas is still poorly understood. During the last 25 years, Aso caldera, Japan, shows minor episodic eruptions, mainly phreatic, associated with steady subsidence ( 1cm/yr) highlighted by levelling and GPS data. Here we analyse the ground deformations at Aso using InSAR data from different satellites (ERS 1-2, Envisat and ALOS) covering the period between 1993 - 2011 and compare it with the eruptive activity. Although the dataset suffers from limitations (e.g. coherence loss, atmospheric artefacts, low signal to noise ratio), we observe a clear subsidence signal from 1996 to 1998. We invert this signal with analytical models to evaluate the deformations source. Results suggest an overall contraction of a magmatic source between 4 and 5 km below the caldera centre. Available geophysical and and geochemical data suggest similar volumes of the contracting source and erupted material. The contraction may have been induced by the release of magmatic fluids, transferring a minor amount of magma and feeding the eruptions. If confirmed by further data, this hypothesis suggests that degassing processes play a crucial role in triggering minor eruptions within open conduit calderas, such as at Aso.

  19. Low-velocity zones in the crust beneath Aso caldera, Kyushu, Japan, derived from receiver function analyses

    NASA Astrophysics Data System (ADS)

    Abe, Yuki; Ohkura, Takahiro; Shibutani, Takuo; Hirahara, Kazuro; Yoshikawa, Shin; Inoue, Hiroyuki

    2017-03-01

    Aso volcano, in central Kyushu Island in southwest Japan, has a large caldera (18 × 25 km) that formed by the ejection of more than 600 km3 of deposits 89 thousand years ago. We calculated receiver functions from teleseismic waveform data obtained from densely distributed stations in and around the caldera. We estimated the crustal S wave velocity structure from the receiver functions by using genetic algorithm inversion. We detected a low-velocity zone (Vs > 2.2 km/s) at a depth of 8-15 km beneath the eastern flank of the central cones. A sill-like deformation source has been detected at a depth of 15.5 km by analyses of GPS data, and a swarm of low-frequency earthquakes exists at depths of 15-25 km just beneath this low-velocity zone. Magma may be newly generated and accumulated in this low-velocity zone as a result of hot intrusions coming from beneath it. Except for the region beneath the eastern flank of the central cones, a second low-velocity zone (Vs > 1.9 km/s) extends in and around the caldera at a depth of 15-23 km, although phenomena representing intrusions have not been detected below it. From the estimated velocity structure, these low-velocity zones are interpreted to contain a maximum of 15% melt or 30% water.

  20. Seismic Attenuation beneath Tateyama Volcano, Central Japan

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Subsurface structures beneath active volcanoes have frequently been investigated (e.g., Oikawa et al., 1994: Sudo et al., 1996), and seismic attenuation beneath some active volcanoes are reported to be strong. On the other hand, few local subsurface structures beneath volcanoes whose volcanic activities are low have been investigated in detail, though it is important to study them to understand the potential of volcanic activity of these volcanoes. Then, we analyzed the seismic attenuation beneath Tateyama volcano (Midagahara volcano) located in central Japan, whose volcanic activity is quite low. We used seismograms obtained by Hi-net deployed by NIED (National Research Institute for Earth Science and Disaster Prevention). Hi-net is one of the densest seismic station networks in the world, and the spatial interval of their seismographs is about 20 km, which is suitable for investigating local structure beneath an individual volcano. We estimated S-wave attenuation using seismograms at five stations near Tateyama volcano for nineteen small, local, shallow earthquakes (M 2.7-4.0) that occurred from January 2012 to December 2013. We divided these earthquakes into six groups according to their hypocenter locations. We used twofold spectral ratios around the first S-arrivals to investigate the S-wave attenuation when S-waves passed through the region beneath Tateyama volcano. We focused on station pairs located on opposite sides of Tateyama volcano to each other, and earthquake pairs whose epicenters were located almost along the line connecting Tateyama volcano and the two stations, so that the spectral ratios reflect a local structure beneath Tateyama volcano. Twofold spectral ratios of all seismograms for S waves having northwestern or southeastern sources show strong attenuation beneath Tateyama volcano. On the other hand, those of seismograms having northeastern or southwestern sources show much weaker attenuation, which suggested that the region of strong

  1. Soil carbon stocks and carbon sequestration rates in seminatural grassland in Aso region, Kumamoto, Southern Japan.

    PubMed

    Toma, Yo; Clifton-Brown, John; Sugiyama, Shinji; Nakaboh, Makoto; Hatano, Ryusuke; Fernández, Fabián G; Ryan Stewart, J; Nishiwaki, Aya; Yamada, Toshihiko

    2013-06-01

    Global soil carbon (C) stocks account for approximately three times that found in the atmosphere. In the Aso mountain region of Southern Japan, seminatural grasslands have been maintained by annual harvests and/or burning for more than 1000 years. Quantification of soil C stocks and C sequestration rates in Aso mountain ecosystem is needed to make well-informed, land-use decisions to maximize C sinks while minimizing C emissions. Soil cores were collected from six sites within 200 km(2) (767-937 m asl.) from the surface down to the k-Ah layer established 7300 years ago by a volcanic eruption. The biological sources of the C stored in the Aso mountain ecosystem were investigated by combining C content at a number of sampling depths with age (using (14) C dating) and δ(13) C isotopic fractionation. Quantification of plant phytoliths at several depths was used to make basic reconstructions of past vegetation and was linked with C-sequestration rates. The mean total C stock of all six sites was 232 Mg C ha(-1) (28-417 Mg C ha(-1) ), which equates to a soil C sequestration rate of 32 kg C ha(-1)  yr(-1) over 7300 years. Mean soil C sequestration rates over 34, 50 and 100 years were estimated by an equation regressing soil C sequestration rate against soil C accumulation interval, which was modeled to be 618, 483 and 332 kg C ha(-1)  yr(-1) , respectively. Such data allows for a deeper understanding in how much C could be sequestered in Miscanthus grasslands at different time scales. In Aso, tribe Andropogoneae (especially Miscanthus and Schizoachyrium genera) and tribe Paniceae contributed between 64% and 100% of soil C based on δ(13) C abundance. We conclude that the seminatural, C4 -dominated grassland system serves as an important C sink, and worthy of future conservation. © 2013 Blackwell Publishing Ltd.

  2. Eruption mechanism as inferred from geomagnetic changes with special attention to the 1989 1990 activity of Aso volcano

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshikazu

    1993-06-01

    Geomagnetic changes associated with the volcanic activity of Aso volcano were detected with a dense network of continuously recording proton-precession magnetometers during the period from June 1989 to June 1990. Magnetic date clearly indicate that changes in the magnetization within the volcano are most probably caused by temperature changes. This activity can be divided into five stages, which are characterized by magnetization and demagnetization of the volcano. These magnetic changes with durations of a few months are definitely correlated with some typical volcanic events at the crater as well as the volcanic tremor activity. The demagnetization stage appears when the vent is covered by a water pool or the volcanic activity is enhanced. The magnetization stage follows the opening of a vent and several large explosions which make the vent permeable. The source of magnetic changes lies at a depth of about 200 m below the crater rim in the southwestern part of the active crater. Magnetic moments responsible for observed magnetic changes at stages 1, 2 and 4 are 3.4, -5.2 and -2.2 Wbm, respectively. The corresponding source volume is estimated as a single sphere of radius 40-50 m or a spherical shell of 100 m or so. An effective mechanism of rapid heating/cooling exists, which is ascribed to the interaction of groundwater and superheated vapor, i.e., a shallow hydrothermal system. This hydrothermal system driven by the surface cap of the vent, controls every feature of the eruptions at the final outlet of Aso volcano.

  3. Mineral and chemical variations within an ash-flow sheet from Aso caldera, Southwestern Japan

    USGS Publications Warehouse

    Lipman, P.W.

    1967-01-01

    Although products of individual volcanic eruptions, especially voluminous ash-flow eruptions, have been considered among the best available samples of natural magmas, detailed petrographic and chemical study indicates that bulk compositions of unaltered Pleistocene ash-flow tuffs from Aso caldera, Japan, deviate significantly from original magmatic compositions. The last major ash-flow sheet from Aso caldera is as much as 150 meters thick and shows a general vertical compositional change from phenocryst-poor rhyodacite upward into phenocryst-rich trachyandesite; this change apparently reflects in inverse order a compositionally zoned magma chamber in which more silicic magma overlay more mafic magma. Details of these magmatic variations were obscured, however, by: (1) mixing of compositionally distinct batches of magma during upwelling in the vent, as indicated by layering and other heterogeneities within single pumice lumps; (2) mixing of particulate fragments-pumice lumps, ash, and phenocrysts-of varied compositions during emplacement, with the result that separate pumice lenses from a single small outcrop may have a compositional range nearly as great as the bulk-rook variation of the entire sheet; (3) density sorting of phenocrysts and ash during eruption and emplacement, resulting in systematic modal variations with distance from the caldera; (4) addition of xenocrysts, resulting in significant contamination and modification of proportions of crystals in the tuffs; and (5) ground-water leaching of glassy fractions during hydration after cooling. Similar complexities characterize ash-flow tuffs under study in southwestern Nevada and in the San Juan Mountains, Colorado, and probably are widespread in other ash-flow fields as well. Caution and careful planning are required in study of the magmatic chemistry and phenocryst mineralogy of these rocks. ?? 1967 Springer-Verlag.

  4. 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.

  5. Crustal deformation associated with the 2016 Kumamoto Earthquake and its effect on the magma system of Aso volcano

    NASA Astrophysics Data System (ADS)

    Ozawa, Taku; Fujita, Eisuke; Ueda, Hideki

    2016-11-01

    An MJMA6.5 earthquake (foreshock) and MJMA7.3 earthquake (mainshock) struck Kumamoto Prefecture on April 14, 2016, and April 16, 2016. To evaluate the effect of crustal deformation due to the earthquake on the Aso magma system, we detected crustal deformation using InSAR and GNSS. From InSAR analysis, we detected large crustal deformations along the Hinagu Fault, the Futagawa Fault, and the northeast extension of the latter fault. It extended to more than 50 km, and the maximum slant-range change exceeded 1 m. Although the obtained crustal deformation was approximately explained by the right-lateral strike-slip on the fault, its details could not be explained by such simple faulting. Additionally, we found complex surface deformation west of the Aso caldera rim, suggesting that shallow fault slips occurred in many known and unknown faults associated with the earthquake. Most of the crustal deformation could be reasonably explained by four rectangle faults located along the Futagawa Fault, in the northeast extension of the Futagawa Fault, alongside the Hinagu Fault, and in the eastern part of the Futagawa Fault. The first three of faults have high dip angles and right-lateral slip. The other was a fault with a low dip angle that branched from the shallow depth of the fault along the Futagawa Fault. The normal-dip right-lateral slip was estimated for this segment. Based on the estimated fault model, we calculated the displacement and stress field around the Aso volcano by the finite-element method (FEM) to evaluate the effects on the Aso magma system. In this calculation, we assumed a spherical soft medium located at a 6-km depth beneath the area south of the Kusasenri region as the magma system and considered only static effects. The result shows complex distributions of displacements and stresses, but we can notice the following significant points. (1) The spherical magma system deformed to an ellipsoid, and the total volume was slightly increased, less than 1%. (2

  6. The susceptibility analysis of landslides induced by earthquake in Aso volcanic area, Japan, scoping the prediction

    NASA Astrophysics Data System (ADS)

    Kubota, Tetsuya; Takeda, Tsuyoshi

    2017-04-01

    Kumamoto earthquake on April 16th 2016 in Kumamoto prefecture, Kyushu Island, Japan with intense seismic scale of M7.3 (maximum acceleration = 1316 gal in Aso volcanic region) yielded countless instances of landslide and debris flow that induced serious damages and causalities in the area, especially in the Aso volcanic mountain range. Hence, field investigation and numerical slope stability analysis were conducted to delve into the characteristics or the prediction factors of the landslides induced by this earthquake. For the numerical analysis, Finite Element Method (FEM) and CSSDP (Critical Slip Surface analysis by Dynamic Programming theory based on limit equilibrium method) were applied to the landslide slopes with seismic acceleration observed. These numerical analysis methods can automatically detect the landslide slip surface which has minimum Fs (factor of safety). The various results and the information obtained through this investigation and analysis were integrated to predict the landslide susceptible slopes in volcanic area induced by earthquakes and rainfalls of their aftermath, considering geologic-geomorphologic features, geo-technical characteristics of the landslides and vegetation effects on the slope stability. Based on the FEM or CSSDP results, the landslides occurred in this earthquake at the mild gradient slope on the ridge have the safety factor of slope Fs=2.20 approximately (without rainfall nor earthquake, and Fs>=1.0 corresponds to stable slope without landslide) and 1.78 2.10 (with the most severe rainfall in the past) while they have approximately Fs=0.40 with the seismic forces in this earthquake (horizontal direction 818 gal, vertical direction -320 gal respectively, observed in the earthquake). It insists that only in case of earthquakes the landslide in volcanic sediment apt to occur at the mild gradient slopes as well as on the ridges with convex cross section. Consequently, the following results are obtained. 1) At volcanic

  7. Volcano Monitoring and Eruption Response in Japan

    NASA Astrophysics Data System (ADS)

    Nakada, S.; Morita, Y.

    2010-12-01

    Although the start of eruption was forecasted at Miyakejima in June 2000, its change since then was largely different from what we expected; the countermeasures always became one step behind. There was a sudden lateral intrusion of the enormous amount magma as far as 30 km away from the volcano. The failure in forecasting comes partly from insufficient consideration of the eruption history and simple analogy of recent, near-steady state eruption events. The 2000 eruption may be reappearance of that of 2.5 ka at Miyakejima. The national project of eruption prediction researches has focused on seismological and geomagnetic investigations to detect the temporal change in the subsurface structure for active volcanoes, together with repeated, multidiscipline intensive observation. These were considered important to understand magma storage and movement, to evaluate the eruption potential, and to forecast the future eruption. Although direct detection of the magma chamber was incomplete, the convex distribution of dense material beneath the summit became common throughout examined volcanoes. It became clear that the part consists of the dike swarms through the conduit drilling project at Unzen. Understanding of the velocity structure by the seismic experiments was very useful to determine the detail location of volcano earthquakes in those volcanoes. Furthermore, combination of seismic, geodetic, geomagnetic and petrological investigations provided us a better imaging of the subsurface structure of several volcanoes. New technology such as the cosmic-ray (muon) radiography, which made the volcano interior visible, will give us the important information on magma ascent in the shallowest part of volcano. Recently, seismological and geodetic monitoring at densely-located observation sites makes possible to image the magma’s ascent and accumulation under volcanoes from the middle to upper crust. This process, of course, needs knowledge on the subsurface structure (depth of

  8. 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.

  9. 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.

  10. 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

  11. Non-tectonic liquefaction-induced large surface displacements in the Aso Valley, Japan, caused by the 2016 Kumamoto earthquake, revealed by ALOS-2 SAR

    NASA Astrophysics Data System (ADS)

    Fujiwara, Satoshi; Morishita, Yu; Nakano, Takayuki; Kobayashi, Tomokazu; Yarai, Hiroshi

    2017-09-01

    We constructed and analyzed full 3-D ground surface displacement field associated with the 2016 Kumamoto (Japan) earthquake using satellite radar images from ALOS-2. Displacements reflect not only tectonic crustal deformation caused by main earthquake faults but also non-tectonic surface deformations. The largest deformations in the earthquake sequence were found in the Aso Valley, along the NW outer rim of the Mt. Aso caldera. Large, independent surface deformations occurred in three areas with diameters of 500 m-2 km in the Aso Valley, and each area was horizontally displaced by more than 2 m to the NNW. These areas are underlain by thick lake-bottom deposits of saturated silt with low penetration resistance. As the direction of the displacements was parallel to the ground slope in each area, the strong seismic motion of the earthquake most probably induced liquefaction in the lake-bottom deposits and the ground surface slid horizontally along the slope on the liquefied silt. Because the areas of the large displacements are closely related to the thickness and shape of the lake-bottom deposits, amplification of the seismic wave in these deposits likely contributed to the liquefaction. A seismograph installed at the Aso Valley recorded co-seismic movement within several seconds of the main shock, indicating a possibility of the strong seismic motion amplifying the horizontal displacement of this area. On the SSE side of the deformed areas, numerous graben-like ruptures developed. As these ruptures are caused by surface tension during the large horizontal displacement, they are not earthquake fault traces and the process of this deformation is non-tectonic.

  12. Big Blast at Sakurajima Volcano, Japan

    NASA Image and Video Library

    2017-09-28

    Although Japan’s Sakura-jima volcano is one of the most active in the world, it rarely makes headlines. One or two small explosions typically occur every few days, with effects no greater than a light dusting of ash on the surrounding cities. On August 18, 2013, a large eruption sent ash 20,000 feet (6,000 meters) above Kagoshima Bay, breaking the established pattern. It was possibly the largest eruption ever from the Showa Crater, which formed in 1946. NASA Earth Observatory images by Jesse Allen and Robert Simmon, using Landsat 8 data from the USGS Earth Explorer. Caption by Robert Simmon. Instrument: Landsat 8 - OLI More details: 1.usa.gov/19WQpBQ 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

  13. Big Blast at Sakurajima Volcano, Japan [annotated

    NASA Image and Video Library

    2017-09-27

    Although Japan’s Sakura-jima volcano is one of the most active in the world, it rarely makes headlines. One or two small explosions typically occur every few days, with effects no greater than a light dusting of ash on the surrounding cities. On August 18, 2013, a large eruption sent ash 20,000 feet (6,000 meters) above Kagoshima Bay, breaking the established pattern. It was possibly the largest eruption ever from the Showa Crater, which formed in 1946. NASA Earth Observatory images by Jesse Allen and Robert Simmon, using Landsat 8 data from the USGS Earth Explorer. Caption by Robert Simmon. Instrument: Landsat 8 - OLI More details: 1.usa.gov/19WQpBQ 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

  14. Broadband seismic observation at Kusatsu-Shirane volcano, Japan

    NASA Astrophysics Data System (ADS)

    Yamawaki, T.; Aoyama, H.; Terada, A.; Nogami, K.

    2011-12-01

    Kusatsu-Shirane volcano, central part of Japan, has repeated phreatic explosions with an interval of several decades. More than 25 years have passed since the last eruption in 1983. Currently persistent seismic and fumarolic activities are observed. Recently, a long tremor was observed in May 2011, for the first time in the last 3 years. The high-frequency tremor lasted for about 7 minutes and were observed by borehole seismometers. It was accompanied by a notable crustal deformation which lasted for about 4 minutes and observed by borehole tiltmeters. The source of the crustal deformation was estimated about 0.5 km to the southeast of Yugama, the main crater lake of the volcano. The location is at the margin of the observation network, which makes it difficult to locate the source precisely. The seismic network of the volcano has consisted of short-period seismometers. Thus very low frequency seismic events, which have often been observed at volcanoes with broadband seismometers, have not been investigated. In order to constrain such pressure sources, to understand better the relationships between high frequency tremor and low frequency deformation, and to investigate very low frequency events, we deployed 3-component seimometers at 3 points, surrounding the deformation source area. Two broadband seismometers, CMG-40T (f0=0.033 Hz) by Güralp Systems were installed to the north and east of the deformation source. And a short-period seismometer, L-4C (f0=1 Hz) by Mark Products, was installed to the south. The seismic data are continuously recorded. One and a half month passed at the time of abstract submission. Neither tremor nor very low frequency event have occurred to date.

  15. Carbon dioxide degassing by advective flow from Usu volcano, Japan.

    PubMed

    Hernández, P A; Notsu, K; Salazar, J M; Mori, T; Natale, G; Okada, H; Virgili, G; Shimoike, Y; Sato, M; Pérez, N M

    2001-04-06

    Magmatic carbon dioxide (CO2) degassing has been documented before the 31 March 2000 eruption of Usu volcano, Hokkaido, Japan. Six months before the eruption, an increase in CO2 flux was detected on the summit caldera, from 120 (September 1998) to 340 metric tons per day (September 1999), followed by a sudden decrease to 39 metric tons per day in June 2000, 3 months after the eruption. The change in CO2 flux and seismic observations suggests that before the eruption, advective processes controlled gas migration toward the surface. The decrease in flux after the eruption at the summit caldera could be due to a rapid release of CO2 during the eruption from ascending dacitic dikes spreading away from the magma chamber beneath the caldera.

  16. Intrinsic and scattering attenuation images of Usu volcano, Japan

    NASA Astrophysics Data System (ADS)

    Prudencio, J.; Taira, T.; Aoki, Y.; Aoyama, H.; Onizawa, S.

    2017-04-01

    We present intrinsic- and scattering-Q attenuation images for Usu volcano (Japan) by analyzing over 1800 vertical seismograms. By fitting the observed envelopes to the diffusion model, we obtained intrinsic and scattering attenuation values at three different frequency bands. Using a back-projection method and assuming a Gaussian-type weighting function, we obtained the 2D images of intrinsic and scattering attenuation. Resolution tests confirm the robustness and reliability of the obtained images. We found that scattering attenuation is the dominant process of energy loss in the frequency range analyzed, which suggests strong spatial heterogeneity. The resultant scattering attenuation images show an increase of attenuation toward the southwest from Toya caldera, which may correspond to deepening of the basement. We also identify an area of low intrinsic and scattering attenuation at the summit of Usu volcano which could be associated with old magma intrusions. Our results demonstrate a strong spatial relation between structural heterogeneities and attenuation processes in volcanic areas and confirm the efficiency of the method which can be used together with conventional imaging techniques.

  17. Transpiration characteristics of forests and shrubland under land cover change within the large caldera of Mt. Aso, Japan

    NASA Astrophysics Data System (ADS)

    Miyazawa, Y.; Inoue, A.; Maruyama, A.

    2013-12-01

    Grassland within a caldera of Mt. Aso has been maintained for fertilizer production from grasses and cattle feeding. Due to the changes in the agricultural and social structure since 1950's, a large part of the grassland was converted to plantations or abandoned to shrublands. Because vegetations of different plant functional types differ in evapotranspiration; ET, a research project was launched to examine the effects of the ongoing land use change on the ET within the caldera, and consequently affect the surface and groundwater discharge of the region. As the part of the project, transpiration rate; E of the major 3 forest types were investigated using sap flow measurements. Based on the measured data, stomatal conductance; Gs was inversely calculated and its response to the environmental factors was modeled using Jarvis-type equation in order to estimate ET of a given part of the caldera based on the plant functional type and the weather data. The selected forests were conifer plantation, deciduous broadleaved plantation and shrubland, which were installed with sap flow sensors to calculate stand-level transpiration rate. Sap flux; Js did not show clear differences among sites despite the large differences in sapwood area. In early summer solar radiation was limited to low levels due to frequent rainfall events and therefore, Js was the function of solar radiation rather than other environmental factors, such as vapor pressure deficit and soil water content. Gs was well regressed with the vapor pressure deficit and solar radiation. The estimated E based on Gs model and the weather data was 0.3-1.2 mm day-1 for each site and was comparable to the E of grassland in other study sites. Results suggested that transpiration rate in growing was not different between vegetations but its annual value are thought to differ due to the different phenology.

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

    NASA Astrophysics Data System (ADS)

    Koike, Katsuaki; Yoshinaga, Tohru; Asaue, Hisafumi

    2014-04-01

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

  19. Tephrostratigraphy and eruptive history of post-caldera stage of Toya Volcano, Hokkaido, northern Japan

    NASA Astrophysics Data System (ADS)

    Miyabuchi, Yasuo; Okuno, Mitsuru; Torii, Masayuki; Yoshimoto, Mitsuhiro; Kobayashi, Tetsuo

    2014-06-01

    A detailed tephrostratigraphy of Toya Volcano in Hokkaido, northern Japan has been constructed to evaluate the post-caldera eruptive history of the volcano. The tephrostratigraphic sequence preserved above the Toya ignimbrite reaches a total thickness of 8 m southeast of the caldera. After the caldera formation (115-112 ka), there was a long quiescent period of more than 60 ka years. The first post-caldera activity started with Nakajima Osarugawa pumice-fall deposit (Nj-Os) inside the caldera at 48 ka. Eruptive activity at Nakajima Volcano resumed at 30 ka with Nakajima Sekinai pumice-fall deposit (Nj-Sk), and was followed by continuous emission of fine ash including abundant accretionary lapilli. Soon after the Nakajima pyroclastic eruption Usu Volcano began its activity with discharges of basaltic ash and scoria (forming the Usu prehistoric tephra) and extrusion of homogeneous lavas namely Usu somma lava, resulting in the formation of the initial volcanic edifice. Subsequently, a large sector collapse occurred between 30 and 20 ka that emplaced the Zenkoji debris avalanche with little break after the formation of the initial Usu volcanic edifice. After the sector collapse, the volcano remained dormant for about 20-30 ka years. Eruptive activity at Usu Volcano resumed in 1663 AD with the most explosive plinian eruption in the post-caldera stage of Toya Volcano. Since then, seven eruptions have been recorded in 1769, 1822, 1853, 1910, 1943-1945, 1977-1978 and 2000 at multi-decadal interval. Total tephra volume during the post-caldera stage is estimated at about 0.9 km3 (dense rock equivalent: DRE), whereas total lava volume is calculated at about 2.3 km3. Therefore, the average magma discharge rate during the post-caldera stage of Toya Volcano is estimated at about 0.03 km3/ky, which is one or two order smaller than those of other Quaternary volcanoes in Japan.

  20. Deep magma feeding system of Fuji volcano, Japan

    NASA Astrophysics Data System (ADS)

    Takahashi, E.; Asano, K.; Nakajima, J.

    2012-12-01

    Fuji volcano is known for its perfect cone shape and it is the largest among Japanese Quaternary volcanoes. For the last 100kya, Fuji has erupted dominantly basalt magma (>>99 vol%), but its eruption style changed (from debris flow and tephra dominant Ko-Fuji or Older Fuji, to lava flow dominant Shin-Fuji or Younger Fuji) at ~15 kya BP. The incompatible trace element composition of the magma changed abruptly between Ko-Fuji and Shin-Fuji. The origin of the voluminous yet monotonous basalt production and the simultaneous changes in volcanic style and magma chemistry in Fuji volcano have been discussed but remain unanswered. Here we report the first high-pressure melting experimental results on Fuji Basalt (Hoei-IV, AD1707) and demonstrate that its main magma chamber is located at ca.25km depth (Asano et al, this conference). We also show seismic tomographic images of Fuji volcano for the first time, which reveal the existence of strong upwelling flow in the mantle and its connection to the voluminous lower crustal magma chamber (Fig.1). The chemistry of Fuji magma is buffered by a lower crustal AFC magma chamber located at 25-35km depth. Mantle derived primitive basalt (FeO/MgO~1.0, saturated with mantle peridotite assemblage, oliv+opx+cpx) changes to evolved basalt (FeO/MgO~2.0, saturated with lower crustal gabbroic assemblage, opx+cpx+pl) by the AFC process. Very frequent low frequency earthquakes just above the magma chamber (red circles in Fig.1) may be due to the injection of basalt magma and/or fluids (Ukawa, 2007). The total lack of silica-rich rocks (basaltic andesite and andesite) in Fuji volcano must be due to the special location of the volcano. As shown in Fig.1 (solid line), the plate boundary between the Eurasia plate and the subducting Phillipine sea plate is located just beneath Fuji volcano (~5 km depth). Large tectonic stress and deformation associated with the plate boundary inhibit the survival of a shallow level magma chamber, which would allow

  1. VHF Radiation Observed During Eruptions of Sakurajima Volcano, Japan, Part II: Continuous RF Discharge Mechanisms

    NASA Astrophysics Data System (ADS)

    Edens, H. E.; Behnke, S. A.; Thomas, R. J.; McNutt, S. R.; Smith, C. M.; Van Eaton, A. R.; Cimarelli, C.; Cigala, V.

    2016-12-01

    We investigate possible mechanisms for the production of Continuous RF (CRF) emissions during explosive volcanic eruptions of Sakurajima volcano in Japan. CRF is a continual production of VHF emissions during the ash production phase of an eruption, lasting anywhere from a fraction of a second up to a minute. CRF has been observed during eruptions of various volcanoes over the last 10 years; in the case of Sakurajima volcano, the CRF phase generally lasts only a few seconds. Multi-parametric observations of CRF were made during a field campaign at Sakurajima volcano, Japan in May and June of 2015. The instrumentation included a 10-station Lightning Mapping Array (LMA), a log-RF waveform derived from one of the LMA stations, a broadband VHF antenna, slow and fast delta-E antennas, high-speed video, and still photography. Data were recorded for several hundred explosive events. We test the hypothesis that CRF is produced by numerous small ( 100 m) leader discharges at the vent of the volcano. We also investigate other possible discharge mechanisms that may be responsible for CRF, by comparing CRF characteristics to VHF emissions from known sources, such as corona discharge and spark discharges. Preliminary results show that CRF is distinct from lightning, as no charge transfer is observed on delta-E instruments, unlike the charge transfer from leader stepping in regular lightning flashes that occur later on during an eruption.

  2. Lightning During the Eruptions at Sakurajima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Thomas, R. J.; Behnke, S. A.; Edens, H. E.; Iguchi, M.; Miki, D.; McNutt, S. R.; Van Eaton, A. R.; Smith, C. M.; Cimarelli, C.; Cigala, V.

    2015-12-01

    In May 2015 our volcano-lightning team spent about 2 weeks at the Sakurajima volcano observing electrical activity during many explosive eruptions. The explosive eruptions sent ash into the atmosphere reaching between 2 and 5 km MSL. Most of the eruptions produced lightning and electrical activity. Our measurements included electric, photographic, seismic, and ascustic. The atmospheric-electricity instruments included a 10-station-LMA, slow antenna, fast antenna, and broad-band-RF. Inaddition to standard photography and video, we had infrared video, low-light video, and high-speed video. The slow antenna showed that typically the predominant charge was negative, but at times it was positive. The larger eruptions show the continual electrical discharges that begin coincident within tenths of a second as the explosion. We have sensed these small discharges in many other volcanic eruptions.

  3. Volcanoes!

    USGS Publications Warehouse

    ,

    1997-01-01

    Volcanoes is an interdisciplinary set of materials for grades 4-8. Through the story of the 1980 eruption of Mount St. Helens, students will answer fundamental questions about volcanoes: "What is a volcano?" "Where do volcanoes occur and why?" "What are the effects of volcanoes on the Earth system?" "What are the risks and the benefits of living near volcanoes?" "Can scientists forecast volcanic eruptions?"

  4. Multiparametric observation of volcanic lightning: Sakurajima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Cimarelli, C.; Alatorre-Ibargüengoitia, M. A.; Aizawa, K.; Yokoo, A.; Díaz-Marina, A.; Iguchi, M.; Dingwell, D. B.

    2016-05-01

    We recorded volcanic lightning generated by Vulcanian explosions at Sakurajima Volcano using a synchronized multiparametric array. Physical properties of lightning are related to plume dynamics, and associated electromagnetic field variations are revealed by video observations (high speed and normal speed) together with infrasound and high sampling rate magnetotelluric signals. Data show that volcanic lightning at Sakurajima mainly occurs in the plume gas thrust region at a few hundred meters above the crater rim, where the overpressure of the turbulent volcanic jets determines the electrification of particles generating a complex charge structure in the growing plume. Organization of charges may be achieved at later stages when the plume transitions from the jet phase to the convective phase. Comparison with atmospheric sounding and maximum plume height data show that the effect of hydrometeors on flash generation at Sakurajima is negligible and can be more prudently considered as an additional factor contributing to the electrification of volcanic plumes.

  5. Scoria cone formation through a violent Strombolian eruption: Irao Volcano, SW Japan

    NASA Astrophysics Data System (ADS)

    Kiyosugi, Koji; Horikawa, Yoshiyuki; Nagao, Takashi; Itaya, Tetsumaru; Connor, Charles B.; Tanaka, Kazuhiro

    2014-01-01

    Scoria cones are common volcanic features and are thought to most commonly develop through the deposition of ballistics produced by gentle Strombolian eruptions and the outward sliding of talus. However, some historic scoria cones have been observed to form with phases of more energetic violent Strombolian eruptions (e.g., the 1943-1952 eruption of Parícutin, central Mexico; the 1975 eruption of Tolbachik, Kamchatka), maintaining volcanic plumes several kilometers in height, sometimes simultaneous with active effusive lava flows. Geologic evidence shows that violent Strombolian eruptions during cone formation may be more common than is generally perceived, and therefore it is important to obtain additional insights about such eruptions to better assess volcanic hazards. We studied Irao Volcano, the largest basaltic monogenetic volcano in the Abu Monogenetic Volcano Group, SW Japan. The geologic features of this volcano are consistent with a violent Strombolian eruption, including voluminous ash and fine lapilli beds (on order of 10-1 km3 DRE) with simultaneous scoria cone formation and lava effusion from the base of the cone. The characteristics of the volcanic products suggest that the rate of magma ascent decreased gradually throughout the eruption and that less explosive Strombolian eruptions increased in frequency during the later stages of activity. During the eruption sequence, the chemical composition of the magma became more differentiated. A new K-Ar age determination for phlogopite crystallized within basalt dates the formation of Irao Volcano at 0.4 ± 0.05 Ma.

  6. Use of Unmanned Aircraft System (UAS) in Response to the 2014 Eruption of Ontake Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Mori, T.; Hashimoto, T.; Terada, A.; Shinohara, H.; Kazahaya, R.; Yoshimoto, M.; Tanaka, R.

    2015-12-01

    On Sept. 27, 2014, a phreatic eruption occurred at Ontake volcano (3067 m a.s.l.), central Japan. The eruption caused an unprecedented volcanic disaster in the last 70 years in Japan. Search and rescue operations started soon after the eruption until they were suspended due to snowfall in late October. Considering the potential hazards of further explosive events and the severe winter condition, an approach to the summit area after late October was very difficult. To reveal the condition of the volcanic activity and foresee the trend, we considered it important to carry out volcanic gas surveys for the dense plumes in the vicinity of the vents using an unmanned aircraft system (UAS). For the surveys at Ontake volcano, the UAS was expected to fly about 8 km roundtrip distance at an altitude of over 3000 m. A multicopter with 8 rotors was adopted and we targeted four types of plume monitoring using the UAS; in-plume monitoring of multiple gas concentrations, SO2 flux measurement with UV spectroscopy, thermography of the vents, and in-plume particle sampling. In order to meet the 1 kg payload of the multicopter, some of the instruments were slimmed down.The UAS campaigns at Ontake volcano were carried out on Nov. 20-21, 2014 and on Jun. 2, 2015 from the safety distance of 3-3.5 km away from the crater. With the UAS surveys, we revealed that the SO2/H2S ratios of volcanic gas were closer to the hydrothermal origin instead of direct magma degassing. The second survey also pointed out that the SO2 emission decreased down below 10 ton/day by June 2015, by taking an advantage of flying the vicinity of the vents before the plume was diluted. Our surveys showed decreasing activity of the volcano, together with the advantages of using UAS in volcano monitoring for inaccessible conditions.

  7. Risk-Free Volcano Observations Using an Unmanned Autonomous Helicopter: seismic observations near the active vent of Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Yasuda, A.; Watanabe, A.; Takeo, M.; Honda, Y.; Kajiwara, K.; Kanda, W.; Iguchi, M.; Yanagisawa, T.

    2010-12-01

    Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We need safe and efficient ways of installing sensors near the summit of active volcanoes. We have been developing an volcano observation system based on an unmanned autonomous vehicle (UAV) for risk-free volcano observations. Our UAV is an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. The UAV is 3.6m long and weighs 84kg with maximum payload of 10kg. The UAV can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time and distance from the operator are 90 minutes and 5km, respectively. We have developed various types of volcano observation techniques adequate for the UAV, such as aeromagnetic survey, taking infrared and visible images from onboard high-resolution cameras, volcanic ash sampling in the vicinity of active vents. Recently, we have developed an earthquake observation module (EOM), which is exclusively designed for the UAV installation in the vicinity of active volcanic vent. In order to meet the various requirements for UAV installation, the EOM is very compact, light-weight (5-6kg), and is solar-powered. It is equipped with GPS for timing, a communication device using cellular-phone network, and triaxial accelerometers. Our first application of the EOM installation using the UAV is one of the most active volcanoes in Japan, Sakurajima volcano. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the vicinity

  8. 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)

  9. 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)

  10. Volcanoes

    SciTech Connect

    Decker, R.W.; Decker, B.

    1989-01-01

    This book describes volcanoes although the authors say they are more to be experienced than described. This book poses more question than answers. The public has developed interest and awareness in volcanism since the first edition eight years ago, maybe because since the time 120 volcanoes have erupted. Of those, the more lethal eruptions were from volcanoes not included in the first edition's World's 101 Most Notorious Volcanoes.

  11. First attenuation study at Usu volcano (Hokkaido, Japan)

    NASA Astrophysics Data System (ADS)

    Prudencio, Janire; Taira, Taka'aki; De Siena, Luca; Onizawa, Shin'ya; Ibañez, Jesús; Hellweg, Margaret; Del Pezzo, Edoardo; Aoyama, Hiroshi; García-Yeguas, Araceli; Oshima, Hiromitsu; Díaz-Moreno, Alejandro

    2014-05-01

    2D and 3D attenuation structures of Usu volcano has been obtained with measurements of diffusion model and coda-normalization method, respectively, with the same data-set used to develop the 3D velocity tomography by Onizawa et al., (2007). We have obtained intrinsic and scattering 2D maps applying the diffusion model which is an approximation of the general energy transport theory developed by Wegler and Lühr (2001) and Wegler (2003). As a result of the theoretical curves with the energy envelopes of the seismograms, we have obtained intrinsic attenuation coefficient and diffusivity coefficient values in the frequency range of 4-16 Hz. Then, We have quantified the contribution of intrinsic and scattering attenuation by inverse quality factor because is more representative. Finally, with a new representation method based in the Gaussian probability function distribution, we have represented the inverse quality factors obtained into 2D contour maps. To obtain 3D attenuation tomography of Deception Island, we have used more than 2000 waveforms recorded at over 288 on land seismic stations. The rays were traced in a 3D velocity model. We have inverted the spectral ratios obtained with the coda normalization method to obtain total-Q values. We resolve 1 km cubic cells. Both results, 2D maps and 3D attenuation structure, have shown that there is likewise agreement with the velocity tomography: the low velocity zones being consistent with regions featuring high attenuation effects and the high velocity zones with regions featuring low attenuation effects. This new models will be a complement to the better understanding of velocity anomalies and will allow remove some grades of uncertainty of the other studies.

  12. 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…

  13. Three-dimensional resistivity modeling of GREATEM survey data from Ontake Volcano, northwest Japan

    NASA Astrophysics Data System (ADS)

    Abd Allah, Sabry; Mogi, Toru

    2016-05-01

    Ontake Volcano is located in central Japan, 200 km northwest of Tokyo and erupted on September 27, 2014. To study the structure of Ontake Volcano and discuss the process of its phreatic eruption, which can help in future eruptions mitigation, airborne electromagnetic (AEM) surveys using the grounded electrical-source airborne transient electromagnetic (GREATEM) system were conducted over Ontake Volcano. Field measurements and data analysis were done by OYO Company under the Sabo project managed by the Ministry of Land, Infrastructure, Transport and Tourism. Processed data and 1D resistivity models were provided by this project. We performed numerical forward modeling to generate a three-dimensional (3D) resistivity structure model that fits the GREATEM data where a composite of 1D resistivity models was used as the starting model. A 3D electromagnetic forward-modeling scheme based on a staggered-grid finite-difference method was modified and used to calculate the response of the 3D resistivity model along each survey line. We verified the model by examining the fit of magnetic-transient responses between the field data and 3D forward-model computed data. The preferred 3D resistivity models show that a moderately resistive structure (30-200 Ω m) is characteristic of most of the volcano, and were able to delineate a hydrothermal zone within the volcanic edifice. This hydrothermal zone may be caused by a previous large sector collapse.

  14. The October 16, 2013 rainfall-induced landslides and associated lahars at Izu Oshima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Miyabuchi, Yasuo; Maeno, Fukashi; Nakada, Setsuya

    2015-09-01

    Intense rainfall related to the typhoon T1326 on October 15-16, 2013 (total 824 mm; maximum hourly rainfall 118.5 mm) triggered numerous landslides and associated lahars at Izu Oshima Volcano, the northernmost part of Izu Mariana volcanic arc, Japan. The landslides were concentrated mainly in a 2-km2 area located on the western slope of Izu Oshima Volcano. Most of the landslides were shallow soil slips (< 2 m thick) in unconsolidated fallout tephra layers overlying lava flows and pyroclastic rocks. The rupture surfaces of them were located near the base of Y1 tephra (AD 1777-1778) and/or the base of Y4 tephra (AD 1421). The Y1 and Y4 tephras differ from the underlying paleosols in permeability, grain size and degree of compaction. The saturated hydraulic conductivities of the paleosols were one to two orders of magnitude smaller than those of the overlying Y1 and Y4 tephras. Most landslides mobilized completely into lahars, traveling along stream channels or flat slopes and flooding at the foot of the volcano. The associated lahars severely damaged inhabited areas and caused thirty five fatalities. Although the lahars eroded slopes and transported boulders up to 1 m in diameter and a large amount of woody debris, they contained more than 90% of sand-to-silt-size particles, similar in composition to the original sliding materials. Sediment discharge volumes from three basins were estimated at 1.8-4.1 × 104 m3/km2, based on debris volumes trapped by sediment retention dams. The characteristics of rainfall-induced landslides and associated lahars at Izu Oshima Volcano in 2013 provide an important lesson about future non-eruption-related landslide and lahar hazards at tephra-rich volcanoes.

  15. Geothermal activity and energy of the Yakedake volcano, Gifu-Nagano, Japan

    SciTech Connect

    Iriyama, Jun

    1996-12-31

    The temperature of the most active solfatara in the summit crater of the Yakedake volcano (altitude 2,455 m Gifu-Nagano, Japan) was 92.2 and 129.4{degrees}C in September 1995 and in October 1994, respectively. The temperature of solfatara in the northern summit dome at an altitude of 2,240 to 2,270 m ranged from 68.2 to 92.5{degrees}C in September 1995. The water sample from a crater pond, Shoga-ike, located on the summit, showed a pH and electrical conductivity of 4.38 and 42.2 {mu}S/cm in October 1991, 4.35 and 42.4 {mu}S/cm in September 1992, 4.11 and 76.6 {mu}S/cm in October 1994, and 4.30 and 45.1 {mu}S/cm in September 1995, respectively. In 1960, the water sample from the same pond showed the pH and electrical conductivity of 3.7 and 80.8 {mu}S/cm, respectively. Although the values of pH and electrical conductivity in 1994 approached to the values at the volcano`s pre-eruption in 1960, the eruption in the summit dome did not occur in 1995. However, a large steam explosion occurred in the Nakanoyu area of the southeastern Mountainside of the volcano. The geothermal energy within the summit dome at an altitude of 2,050 to 2,455 m of the Yakedake volcano is calculated, using new data, to be about 4.8 x 10{sup 17} J, which represents a thermal power output of 5.1 x 10{sup 2} MW{sub th} averaged over 30 yrs.

  16. Elastic models for the magma intrusion associated with the 2000 eruption of Usu Volcano, Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Jousset, Philippe; Mori, Hitoshi; Okada, Hiromu

    2003-07-01

    After 23 years of dormancy, Usu Volcano (Hokkaido, Japan) erupted on March 31, 2000. Many observations (seismicity, deformation rates, gravity data, groundwater level monitoring) show that the period of intense activity was short, starting abruptly, and continuing for ca. 5 months with a decreasing rate. Uplift was observed at two successive and separate locations at the time of the eruption. We obtained GPS and microgravity data at Usu Volcano for two intervals, the first from August 1996 to July 1998, once every 2-4 months, and the second in November 2000, 2 months after the end of the eruption. Between July 1998 and November 2000, the displacements and gravity variations are among the largest ever recorded on an active volcano in association with an eruption. We review three different elastic models commonly used in volcano-geodesy (sphere, fault system, fissure zone) and invert the high-quality data using each of these models. The combined inversion of GPS and microgravity data leads to the best solution in the least-squares sense. It is compatible with the intrusion of approximately 5×10 11 kg of new magma into the western part of Usu Volcano. This appears to have occurred in a subvertical fracture zone (about 2.4 km length, 0.1 km width) aligned in the east-west direction. The fracture zone is between 0.4 and 3.3 km depth with an extension of about 30 m. The fractures are likely to be filled with material having a density slightly higher than the density of old products of Mount Usu, i.e. about 2400 kg m -3. This model is consistent with the locations and magnitudes of the earthquakes recorded during the period of intense seismic activity in April and May 2000. These earthquakes correspond to the boundaries of the intruded magma body. The model suggests that the two locations of uplift are not independent.

  17. Elastic modelling of magma intrusions: example of the 2000 eruption of Usu Volcano, Japan.

    NASA Astrophysics Data System (ADS)

    Jousset, P.; Mori, H.; Okada, H.

    2003-04-01

    After 23 years of dormancy, Usu Volcano (Hokkaido, Japan) erupted on 31st of March, 2000. Many observations (seismicity, deformation rates, gravity observations, groundwater level monitoring) show that the period of intense activity was short, starting abruptly, and continuing for ca. 5 months with a decreasing rate. Uplift was observed at two successive and separate locations at the time of the eruption. We obtained GPS and microgravity data at Usu Volcano for two intervals, first from August 1996 to July 1998, once every 2 to 4 months, and second in November 2000, 2 months after the end of the eruption. Between July 1998 and November 2000, the displacements and gravity variations are among the largest ever recorded on an active volcano in association with an eruption. We review three different elastic models commonly used in volcano-geodesy (sphere, fault system, fissure zone) and invert the high quality data using each of these models. The combined inversion of GPS and microgravity data leads to the best solution in the least-squares sense. It is compatible with the intrusion of approximately 5× 1011 kg of new magma into the western part of Usu Volcano. This appears to have occurred in a subvertical fracture zone (about 2.4 km length, 0.1 km width) aligned in the East-West direction. The fracture zone is between 0.4 and 3.3 km depth with an extension of about 30 m. The fractures are likely to be filled with material having a density slightly higher than the density of old products of Mount Usu, i.e., about 2400 kg m-3. This model is consistent with the locations and magnitudes of the earthquakes recorded during the period of the intense seismic activity in April and May 2000. These earthquakes correspond to the boundaries of the intruded magma body. The model suggests that the two locations of uplift are not independent.

  18. 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.

  19. 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.

  20. 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.

  1. Lithospheric Contributions to Arc Magmatism: Isotope Variations Along Strike in Volcanoes of Honshu, Japan

    PubMed

    Kersting; Arculus; Gust

    1996-06-07

    Major chemical exchange between the crust and mantle occurs in subduction zone environments, profoundly affecting the chemical evolution of Earth. The relative contributions of the subducting slab, mantle wedge, and arc lithosphere to the generation of island arc magmas, and ultimately new continental crust, are controversial. Isotopic data for lavas from a transect of volcanoes in a single arc segment of northern Honshu, Japan, have distinct variations coincident with changes in crustal lithology. These data imply that the relatively thin crustal lithosphere is an active geochemical filter for all traversing magmas and is responsible for significant modification of primary mantle melts.

  2. Episodic Deep Fluid Expulsion at Mud Volcanoes in the Kumano Forearc Basin, SE Offshore Japan

    NASA Astrophysics Data System (ADS)

    Hammerschmidt, S.; Kopf, A.

    2014-12-01

    Compressional forces at convergent margins govern a variety of processes, most prominently earthquakes, landslides and mud volcanoes in the forearc. Although all seem related to fluid pressure changes, mud volcanoes are not only characterized by expulsion of fluids, but also fluidized mud and clasts that got ripped-up during mud ascension. They hence provide information regarding mobilization depth, diagenetic overprint, and geodynamic pathways. At the Nankai Trough subduction zone, SE offshore Japan, mud volcanism id common and supposed to be related to seismogenic processes. During MARUM Expedition SO-222 with R/V SONNE, mud volcanoes in the Kumano forearc basin were mapped, cored and sampled. By extending the Integrated Ocean Drilling Program (IODP) Kumano transect landwards, 5 new mud volcanoes were identified by multibeam mapping. Cores revealed mud breccia with semi-consolidated silt- to claystone clasts and gaseous fluid escape structures, while the hemipelagic background sediments are characterized by intercalations of turbidites, ash layers and calcareous fossils. Clasts were subject to thin-section analyses, and the cores were sampled for XRD analyses and radiocarbon dating. Clasts showed prominent deformation structures, neomorphism and pores and fractures filled with polycrystalline quartz and/or calcite cement, probably formed during deep burial and early metamorphosis. Illite crystallinity based on XRD measurements varies between 0.24 and 0.38, which implies that the material originates from the Anchizone at depths ≥ 4 km. Radiocarbon dating revealed ages between 4450 and 30300 yr cal. BP, with age reversals occurring not earlier than 17000 yr cal. BP. Radiocarbon dating beneath turbidites and ash layers found at mud volcano #9 points to an episodic occurrence of these earthquake-related features in intervals of ca. 620 yr, while the mud volcano itself remained inactive. In summary, the preliminary results suggest that the mud volcanoes are nurtured

  3. 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

  4. Aeromagnetic survey using an unmanned autonomous helicopter over Tarumae Volcano, northern Japan

    NASA Astrophysics Data System (ADS)

    Hashimoto, Takeshi; Koyama, Takao; Kaneko, Takayuki; Ohminato, Takao; Yanagisawa, Takatoshi; Yoshimoto, Mitsuhiro; Suzuki, Eiichi

    2014-09-01

    Unmanned aerial vehicles (UAVs) have recently received attention in various research fields for their ability to perform measurements, surveillance, and operations in hazardous areas. Our application is volcano surveillance, in which we used an unmanned autonomous helicopter to conduct a dense low-altitude aeromagnetic survey over Tarumae Volcano, northern Japan. In autonomous flight, we demonstrated positioning control with an accuracy of ~10 m, which would be difficult for an ordinary crewed vehicle. In contrast to ground-based magnetic measurement, which is highly susceptible to local anomalies, the field gradient in the air with a terrain clearance of 100 to 300 m was fairly small at 1 nT/m. This result suggests that detection of temporal changes of an order of 10 nT may be feasible through a direct comparison of magnetic data between separate surveys by means of such a system, rather than that obtained by upward continuation to a common reduction surface. We assessed the temporal magnetic changes in the air, assuming the same remagnetising source within the volcano that was recently determined through ground surveys. We conclude that these expected temporal changes would reach a detection level in several years through a future survey in the air with the same autonomous vehicle.

  5. Local-Scale Ambient Noise Tomography In and Around the Naruko Volcano, NE Japan

    NASA Astrophysics Data System (ADS)

    Tamura, J.; Okada, T.

    2014-12-01

    The 2008 Iwate-Miyagi Nairiku earthquake (M7.2) occurred along a fault in northeastern Japan. The focal area is surrounded with four quaternary volcanoes: Yakeishi, Kurikoma, Onikobe caldera, and Naruko volcano. In a previous study of Okada et al. (2014), they conducted seismic tomography in and around the focal area, and found low velocity zones (LVZ) with high Vp/Vs beneath the volcanoes. They suggest that those LVZs could correspond to areas with over-pressurized fluids, which promoted the occurrence of the earthquake. One of their remaining issues in their study, however, is that a possible LVZ was not clearly found beneath the Naruko volcano, which is located on the south edge of aftershock distribution. In this study, we performed ambient noise tomography in an attempt to identify the possible LVZ beneath Naruko using seismic stations, which are densely deployed in the Naruko volcanic area. After the pre-processing (Bensen et al. 2007) to obtain Rayleigh-wave Green's function, we measure phase velocity dispersion curves as described in Lin et al. (2008). Then, surface-wave tomography (Barmin et al. 2001) is performed from 0.15 Hz to 0.5 Hz with a frequency step of 0.05 Hz. As a final step, we invert phase velocities for a 1-D Vs model at each grid point by nonlinear inversion(Tarantola and Valette, 1982). The Vs structure shows two LVZs beneath Naruko and Onikobe. The LVZ of Naruko, however, is merged into that of Onikobe at around 4 km depths and is not resolved in deeper crust.

  6. Repeated aeromagnetic surveys in Shinmoe-dake volcano, Japan by using unmanned helicopter

    NASA Astrophysics Data System (ADS)

    Koyama, T.; Kaneko, T.; Ohminato, T.; Watanabe, A.; Takeo, M.; Yanagisawa, T.; Honda, Y.

    2016-12-01

    We repeatedly conducted aeromagnetic surveys at Shinmoe-dake volcano, Japan by using unmanned helicopter, and elucidated magnetization structure and its temporal change. At the beginning of 2011, Shinmoe-dake volcano has done magmatic eruptions. After ceasing activities of volcanic eruptions, the first aeromagnetic survey by an unmanned helicopter was performed in the western part of Shinmoe-dake volcano in May 2011. The advantage to use unmanned vehicle for volcanic survey is ability of the safe flight in lower altitude with precise tracks. It enable us forthcoming repeated survey on the same tracks and elucidate the temporal changes of the magnetic fields. The geomagnetic total intensity measurement flight was conducted by installing cesium optical pumping magnetometer on the helicopter, in which the measurement line intervals were almost 100 m and the altitudes were also fixed at almost 100 m above the ground except above the crater. Total measurement length was about 85 km. The data analysis revealed that the averaged magnetization is about 1.5 A/m, typical value of andesite rock, and some horizontal anomalies can be shown.After that, we conducted four repeated surveys so far, and notable temporal changes are detected just around the crater of Shinmoe-dake volcano due to gaining magnetization by cooling of lava which has accumulated in the crater at the 2011 eruptions. The cooling rate just follows square root of elapsed time from the eruptive events, and thus the cooling is being simply done by thermal diffusion. Magnetizing, however, goes on too fast to be done by thermal diffusion only at the surface of lava, and so the cooling may be very effectively done also inside the lava by evaporating water.In this paper, we'll show the detailed results of measurements and discuss the temporal changes of magnetization.

  7. Volcanoes

    MedlinePlus

    ... Earth's crust. Hot rock, steam, poisonous gases, and ash reach the Earth's surface when a volcano erupts. ... rain, fires, and even tsunamis. Volcanic gas and ash can damage the lungs of small infants, older ...

  8. 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.

  9. Characterization of fine volcanic ash from explosive eruption from Sakurajima volcano, South Japan

    NASA Astrophysics Data System (ADS)

    Nanayama, F.; Furukawa, R.; Ishizuka, Y.; Yamamoto, T.; Geshi, N.; Oishi, M.

    2013-12-01

    Explosive volcanic eruptions can affect infrastructure and ecosystem by their dispersion of the volcanic particle. Characterization of volcanic particle expelled by explosive eruption is crucial for evaluating for quantitative hazard assessment by future volcanic eruption. Especially for fine volcanic ash less than 64 micron in diameter, it can disperse vast area from the source volcano and be easily remobilized by surface wind and precipitation after the deposition. As fine volcanic ash is not preserved well at the earth surface and in strata except for enormously large scale volcanic eruption. In order to quantify quantitative characteristics of fine volcanic ash particle, we sampled volcanic ash directly falling from the eruption cloud from Showa crater, the most active vent of Sakurajima volcano, just before landing on ground. We newly adopted high precision digital microscope and particle grain size analyzer to develop hazard evaluation method of fine volcanic ash particle. Field survey was performed 5 sequential days in January, 2013 to take tamper-proof volcanic ash samples directly obtained from the eruption cloud of the Sakurajima volcano using disposable paper dishes and plastic pails. Samples were taken twice a day with time-stamp in 40 localities from 2.5 km to 43 km distant from the volcano. Japan Meteorological Agency reported 16 explosive eruptions of vulcanian style occurred during our survey and we took 140 samples of volcanic ash. Grain size distribution of volcanic ash was measured by particle grain size analyzer (Mophologi G3S) detecting each grain with parameters of particle diameter (0.3 micron - 1 mm), perimeter, length, area, circularity, convexity, solidity, and intensity. Component of volcanic ash was analyzed by CCD optical microscope (VHX-2000) which can take high resolution optical image with magnifying power of 100-2500. We discriminated each volcanic ash particle by color, texture of surface, and internal structure. Grain size

  10. The “anomalous cedar trees” of Lake Ashi, Hakone Volcano, Japan

    USGS Publications Warehouse

    Oki, Y.

    1984-01-01

    On the bottom of Lake Ashi at Hakone, Japan, there stand great trees that, since ancient times, have been widely known as the "Anomalous Cedar Trees" of Ashi. It is not known why these trees grow on the bottom of the lake, and it remains one of the mysteries of Hakone. It was formerly thought that, at the time Lake Ashi was born, a great forest of cedar trees which was growing in the caldera of the volcano sank into the water. From radioactive carbon dating techniques, it is known that a steam explosion in the Kami Mountains created the caldera approximately 3,000 years ago. The age of the "Anomalous Cedars" is placed at approximately. 

  11. Rheological Variations in Lahars Expected to Flow Along the Sides of Sakurajima and Ontake Volcanoes, Japan

    NASA Astrophysics Data System (ADS)

    Kurokawa, A. K.; Ishibashi, H.

    2016-12-01

    Volcanic ash is known to accumulate on the ground surface around volcano after eruptions. Once the ash gains weight and mixes with water to a critical point, the mixture of volcanic ash and water runs down a side of volcano causing severe damage to the ambient environment. The flow is referred to as lahar that is widely observed all over the world and it occasionally generates seismic signals [Walsh et al., 2016; Ogiso and Yomogida, 2015]. Sometimes it happens just after an eruption [Nakayama and Kuroda, 2003] whereas a large debris flow, which occurred about 30 years after the latest eruption due to heavy rainfall is also reported [Ogiso and Yomogida, 2015]. Thus when the lahar starts flowing is a key. In order to understand flow characteristics of lahar, it is important to focus on the rheology. However, little is known about the rheological property although the experimental condition can be controlled at atmospheric pressure and ambient temperature. This is an advantage when compared with magma and rock, which need to reach high-pressure and/or high-temperature conditions to be measured. Based on the background, we have performed basic rheological measurements using mixtures of water and volcanic ashes collected at Sakurajima and Ontake volcanoes in Japan. The first important point of our findings is that the two types of mixtures show non-linear characteristics differently. For instance, the viscosity variation strongly depends on the water content in the case of Sakurajima sample while the viscosity fluctuates within a certain definite range of shear rate using Ontake sample. Since these non-linear characteristics are related to structural changes in the flow, our results indicate that the flow of lahar is time-variable and complicated. In this presentation, we report the non-linear rheology in detail and go into the relation to temporal changes in the flow.

  12. Monitoring eruption activity from temporal stress changes at Mt. Ontake volcano, Japan

    NASA Astrophysics Data System (ADS)

    Terakawa, T.; Kato, A.; Yamanaka, Y.; Maeda, Y.; Horikawa, S.; Matsuhiro, K.; Okuda, T.

    2015-12-01

    On 27 September 2014, Mt. Ontake in Japan produced a phreatic (steam type) eruption with a Volcanic Explosivity Index value of 2 after being dormant for seven years. The local stress field around volcanoes is the superposition of the regional stress field and stress perturbations related to volcanic activity. Temporal stress changes over periods of weeks to months are generally attributed to volcanic processes. Here we show that monitoring temporal changes in the local stress field beneath Mt. Ontake, using focal mechanism solutions of volcano-tectonic (VT) earthquakes, is an effective tool for assessing the state of volcanic activity. We estimated focal mechanism solutions of 157 VT earthquakes beneath Mt. Ontake from August 2014 to March 2015, assuming that the source was double-couple. Pre-eruption seismicity was dominated by normal faulting with east-west tension, whereas most post-eruption events were reverse faulting with east-west compression. The misfit angle between observed slip vectors and those derived theoretically from the regional (i.e., background) stress pattern is used to evaluate the deviation of the local stress field, or the stress perturbation related to volcanic activity. The moving average of misfit angles tended to exceed 90° before the eruption, and showed a marked decrease immediately after the eruption. This indicates that during the precursory period the local stress field beneath Mt. Ontake was rotated by stress perturbations caused by the inflation of magmatic/hydrothermal fluids. Post-eruption events of reverse faulting acted to shrink the volcanic edifice after expulsion of volcanic ejecta, controlled by the regional stress field. The misfit angle is a good indicator of the state of volcanic activity. The monitoring method by using this indicator is applicable to other volcanoes and may contribute to the mitigation of volcanic hazards.

  13. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Image and Video Library

    2000-08-10

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people. This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features. http://photojournal.jpl.nasa.gov/catalog/PIA02771

  14. Magma Genesis of Sakurajima, the Quaternary post- Aira caldera volcano, southern Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Suzuki, J.; Yoshikawa, M.; Kobayashi, T.; Miki, D.; Takemura, K.

    2012-12-01

    Sakurajima volcano is the Quaternary post-caldera volcano of Aira caldera, which was caused by the eruption of huge amount of silicic pyroclastics, situated on Ryukyu arc, southern Kyushu Island, Japan. This volcano is quite active, so it can be considered that the preparation of next caldera-forming eruption with huge amount of silicic magma is proceeding. It is, therefore, expected that the investigation of magma genesis of Sakurajima volcano give us information for the mechanism generating huge amount of silicic magma, which cause the caldera formation. We analyzed major and trace elements with Sr, Nd and Pb isotopic compositions of volcanic rocks from Sakurajima volcano. We sampled (ol) - opx - cpx - pl andesite and dacite from almost all the volcanic units defined by Fukuyama and Ono (1981). In addition to Sakurajima samples, we also studied basaltic rocks erupted at pre-caldera stage of the Aira caldera to estimate the primary magma of Sakurajima volcano. Major and trace element variations generally show linear trends on the Harker diagrams, with the exception of P2O5 and TiO2. Based on the trend of P2O5 vs.SiO2, we divided studied samples low-P (P2O5 < 0.15 wt. %) and high-P (P2O5 > 0.15 wt. %) groups and these groups also display two distinct trends on TiO2-SiO2 diagram. The composition of trace elements shows typical island arc character as depletion of Nb and enrichments of Rb, K and Pb, suggesting addition of aqueous fluids to the mantle wedge. The Zr and Nb concentrations make a liner trend (Zr/Nb = 27) and this trend across from tend of MORB (Zr/Nb = 35) to that of crustal materials (Zr/Nb=17). The Sr, Nd and Pb isotopic compositions broadly plot to on the mixing curve connecting MORB-type mantle and sediments of the Philippine Sea Plate, indicating that the primary magma was generated by partial melting of MORB-type mantle wedge, which was hydrated with fluids derived from the subducted Philippine Sea sediments. But we found that our data plot apart

  15. Aeromagnetic Constraints on the Subsurface Structure of Usu Volcano, Hokkaido Japan

    NASA Astrophysics Data System (ADS)

    Nakatsuka, T.; Okuma, S.; Ishizuka, Y.

    2010-12-01

    Usu Volcano, Hokkaido, Japan consists mainly of dacitic volcanic rocks underlain by basaltic somma lava and Pliocene - Pleistocene andesitic volcanic rocks and has erupted every 20-30 years. Latest eruption in 2000 took place for the first time after the 1977-1978 eruption. A helicopter-borne high-resolution aeromagnetic survey was conducted to better understand the subsurface structure of the volcano almost three months after the start of the eruption. The survey with a stinger-mounted Cs magnetometer was flown at an altitude of 150 m above terrain along north-south survey lines and east-west tie lines, spaced 200 m and 1000 m apart, respectively. DGPS with an accuracy of 50cm was employed for flight-path recovery. Total magnetic intensity was observed every 0.1 second and anomaly was calculated as residual values after subtracting the IGRF-10 field. Magnetic anomalies on a smoothed observation surface were calculated by the reduction method, assuming equivalent anomalies below the actual observation surface (Nakatsuka and Okuma, 2006a). Preliminary 3-D imaging of magnetic anomalies over Usu Volcano was also conducted to constrain the subsurface structure. The 3-D magnetic model indicates that magnetization highs occupy the main edifice of Usu Volcano, suggesting the subsurface distribution of the Usu Somma Lava with a thickness of 1,000 m at the maximum. While, (negative) magnetization lows lie northwest of the Nishi-Yama Craters Area and on the Higashi-Maruyama Cryptodome, where Pliocene and Pleistocene volcanic rocks are distributed, respectively. Their reverse magnetization can be responsible for the magnetization lows. Although the survey was successful to better understand the surface and subsurface distribution of volcanic rocks which constitute the edifice and basement of Usu Volcano, some limitations exist. Any information about the magmas intruded during recent eruptions such as in 1977-1978 and 2000 has not been obtained by the high

  16. Crustal deformation of Miyakejima volcano, Japan since the eruption of 2000 using dense GPS campaign observation

    NASA Astrophysics Data System (ADS)

    Fukui, M.; Matsushima, T.; Oikawa, J.; Watanabe, A.; Okuda, T.; Ozawa, T.; Kohno, Y.; Miyagi, Y.

    2013-12-01

    Miyakejima is an active volcanic Island located about 175 km south of Tokyo, Japan. Miyakejima volcano erupted approximately every 20 years in the past 100 years. The latest eruptive activities since 2000 was different from those of the last 100 years, in that the activities included a caldera formation for the first time in 2500 years and gigantic volcanic gas emission that forced islander to evacuate over four and half years. In 2000, a dense GPS observation campaign had detected the magma intrusion in detail (e.g., Irwan et al., 2003; Murase et al., 2006). However, this campaign observation ceased from 2002 to 2010 because a large amount of volcanic gas prevented from entering to the island. Since 2011, we restarted the campaign observation by the dense GPS network, and examined the ongoing magma accumulation process beneath Miyakejima volcano to get insights about the future activity. In this analysis, we combined the data of our campaign observations, the data of the University Union in 2000, and the GEONET data. The observation data were analyzed by RTK-LIB (Takasu et al., 2007) using GPS precise ephemeris from IGS. We estimated the locations and volumes of the pressure sources beneth Miyakejima using an elevation-modified Mogi model (Fukui et al., 2003) and open crack model (Okada, 1992) during the two periods (2000 ~ 2012 and 2011 ~ 2012). We used the software of Magnetic and Geodetic data Computer Analysis Program for Volcano (MaGCAP-V) (Fukui et al., 2010), and estimated the source parameters by trial and error. During 2000 and 2012, a contracting spherical source and contracting dyke were estimated beneath the caldera and at the southwestern part of the island, respectively. In contrast, during 2011 and 2012, an spherical inflation source was estimated a few km beneath the caldera. This result suggest that Miyakejima is now storing new magma for the next eruption. Geospatial Information Authority of Japan (GSI) (2011) suggested that the inflation started

  17. Character and origin of lithofacies in the conduit of Unzen volcano, Japan

    NASA Astrophysics Data System (ADS)

    Goto, Yoshihiko; Nakada, Setsuya; Kurokawa, Masaru; Shimano, Taketo; Sugimoto, Takeshi; Sakuma, Sumio; Hoshizumi, Hideo; Yoshimoto, Mitsuhiro; Uto, Kozo

    2008-07-01

    Unzen, western Kyushu, Japan, is an andesitic to dacitic, polygenetic volcano that reaches an elevation of 1486 m above sea level. A 1996-m-long hole has been drilled on a slanted trajectory passing beneath the volcano, penetrating the conduit zone of the volcano at 30-150 m below sea level. Spot drill cores, totalling 75 m in length, were recovered between lengths 1582 to 1996 m of the hole. The principal lithofacies of the cores are polymict volcanic breccia (74 vol.% of total drill cores), coherent dacite (13 vol.%), coherent andesite (6 vol.%), partly brecciated coherent dacite (5 vol.%), and volcaniclastic veins (2 vol.%). The polymict volcanic breccia is poorly sorted, non-graded and made up of various clasts of andesite/dacite composition, 1-120 cm across, in a matrix of andesite/dacite fragments, up to 5 mm across. The clasts are subangular to subrounded, non-vesicular to vesicular, and contain 62-66 wt.% SiO 2. This facies is interpreted as forming the subvertical body of a diatreme, and to have been produced by fragmentation of vent-conduit wall rocks by explosive eruptions and associated gravitational failure. The coherent dacite (SiO 2 = 66-67 wt.%) is uniform to flow-banded and commonly has chilled margins. The dacite is porphyritic containing phenocrysts of plagioclase, hornblende, biotite and minor quartz in a non-vesicular groundmass. This facies is interpreted as representing dykes that have intruded into the polymict volcanic breccia. The coherent andesite (SiO 2 = 59 wt.%) and partly brecciated coherent dacite (SiO 2 = 69 wt.%) are massive to fractured, vesicular and porphyritic. These facies are interpreted to be lavas extruded during the old stage (500-300 ka) of the evolution of the Unzen volcano. The volcaniclastic veins occur within all the lithofacies described and range from 0.1 to 250 mm wide. The veins consist of volcanic lithic and mineral fragments up to several millimetres across, and are inferred to have formed by injection of high

  18. Diffuse degassing survey at the Higashi Izu monogenetic volcano field, Japan

    NASA Astrophysics Data System (ADS)

    Notsu, Kenji; Pérez, Nemesio M.; Fujii, Naoyuki; Hernández, Pedro A.; Mori, Toshiya; Padrón, Eleazar; Melián, Gladys

    2016-04-01

    The Higashi-Izu monogenetic volcanic group, which consists of more than 60 volcanoes, overlies the polygenetic volcanoes in the eastern part of the Izu peninsula, Japan, which are distributed over the area of 350 km2. Some of the monogenetic volcanoes are located on northwest-southeast alignments, suggesting that they developed along fissures. Recent volcanic activity occurred offshore, e.g., at the Izu-Oshima volcano, which erupted in 1986 and a submarine eruption of the small new Teishi knoll off eastern Izu Peninsula in 1989 (Hasebe et al., 2001). This study was carried out to investigate the possible relationship of diffuse CO2 emission and the recent seismic activity recorded NE of Higashi Izu monogenetic volcanic field, to quantify the rate at which CO2 is diffusely degassed from the studied area including Omuroyama volcano and to identify the structures controlling the degassing process. Measurements were carried out over a three day period from 8-10 July 2013. Diffuse CO2 emission surveys were always carried out following the accumulation chamber method and spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. Soil gas samples were collected at 30-40 cm depth by withdrawal into 60 cc hypodermic syringes to characterize the chemical and isotopic composition of the soil gas. At Omurayama volcano, soil CO2 efflux values ranged from non-detectable to 97.5 g m-2 d-1, while at the seismic swarm zone ranged from 1.5 to 233.2 g m-2 d-1 and at the fault zone ranged from 5.7 to 101.2 g m-2 d-1. Probability-plot technique of all CO2 efflux data showed two different populations, background with a mean of 8.7 g m-2 d-1 and peak with a mean of 92.7 g m-2 d-1. In order to strength the deep seated contribution to the soil gases at the studied are, carbon isotopic analysis were performed in the CO2 gas. Soil gases (He, CO2 and N2) showed a clear mixing trend between air composition and a rich CO2 end member, suggesting the

  19. VHF Radiation Observed During Eruptions of Sakurajima Volcano, Japan, Part I: Overview and Characteristics of Continuous RF

    NASA Astrophysics Data System (ADS)

    Behnke, S. A.; Edens, H. E.; Thomas, R. J.; McNutt, S. R.; Smith, C. M.; Van Eaton, A. R.; Cimarelli, C.; Cigala, V.

    2016-12-01

    Volcanic plumes resulting from explosive eruptions are commonly electrified and lightning is frequently observed during eruptions. Over the past 10 years VHF lightning mapping arrays (LMAs) have been used to study the electrical discharges in volcanic plumes from volcanoes in Alaska (USA), Iceland, Chile, and Japan. In addition to VHF emissions typical of lightning, during explosive eruptions LMAs have also recorded a source of VHF radiation distinct from lightning. This distinct source of radiation is referred to as continuous RF (CRF) and is characterized by relatively high rates of impulsive radiation events over long time scales (several to tens of seconds). Continuous RF is observed simultaneous with the onset of explosive eruptions and originates at low altitude - at or near the vent of the volcano. Continuous RF has only been observed while the volcano is actively ejecting ash. The source of the CRF is unknown, but has been hypothesized to be due to numerous, small ( 100 m), leader-forming discharges at the vent of the volcano. A new study is underway to gain further insight into the source of CRF emissions. In May and June of 2015 multi-parametric observations of volcanic lightning were conducted at Sakurajima volcano in Japan. Sakurajima produces frequent small-scale eruptions (plume heights 1-3 km) and during the main observation period several hundred explosive events occurred. The electrical activity was measured with a 10 station LMA, log-RF waveform, a broadband VHF antenna, slow and fast antennas, high-speed video, and still photography. Seismometers, infrasound sensors, infrared video, and low light video were used to measure the eruptive activity. We present an overview of the CRF observations obtained during the field deployment in Japan, including the electrical characteristics of CRF and the characteristics of the eruptive activity producing the CRF.

  20. Observations of eruption clouds from Sakura-zima volcano, Kyushu, Japan from Skylab 4

    USGS Publications Warehouse

    Friedman, J.D.; Heiken, G.; Randerson, D.; McKay, D.S.

    1976-01-01

    Hasselblad and Nikon stereographic photographs taken from Skylab between 9 June 1973 and 1 February 1974 give synoptic plan views of several entire eruption clouds emanating from Sakura-zima volcano in Kagoshima Bay, Kyushu, Japan. Analytical plots of these stereographic pairs, studied in combination with meteorological data, indicate that the eruption clouds did not penetrate the tropopause and thus did not create a stratospheric dust veil of long residence time. A horizontal eddy diffusivity of the order of 106 cm2 s-1 and a vertical eddy diffusivity of the order of 105 cm2 s-1 were calculated from the observed plume dimensions and from available meteorological data. These observations are the first, direct evidence that explosive eruption at an estimated energy level of about 1018 ergs per paroxysm may be too small under atmospheric conditions similar to those prevailing over Sakura-zima for volcanic effluents to penetrate low-level tropospheric temperature inversions and, consequently, the tropopause over northern middle latitudes. Maximum elevation of the volcanic clouds was determined to be 3.4 km. The cumulative thermal energy release in the rise of volcanic plumes for 385 observed explosive eruptions was estimated to be 1020 to 1021 ergs (1013 to 1014 J), but the entire thermal energy release associated with pyroclastic activity may be of the order of 2.5 ?? 1022 ergs (2.5 ?? 1015 J). Estimation of the kinetic energy component of explosive eruptions via satellite observation and meteorological consideration of eruption clouds is thus useful in volcanology as an alternative technique to confirm the kinetic energy estimates made by ground-based geological and geophysical methods, and to aid in construction of physical models of potential and historical tephra-fallout sectors with implications for volcano-hazard prediction. ?? 1976.

  1. Multi-parametric Observation of Volcanic Lightning at Sakurajima Volcano, Japan.

    NASA Astrophysics Data System (ADS)

    Cimarelli, C.; Alatorre-Ibarguengoitia, M.; Aizawa, K.; Yokoo, A.; Dingwell, D. B.

    2014-12-01

    Ash-rich volcanic plumes are very often associated with electrical discharges producing majestic display of lightning. Observation and understanding of this phenomenon can shed light on crucial properties of the plume such as mass eruption rate and content of fine particles, as recently demonstrated by laboratory investigation of volcanic lightning (Cimarelli et al., 2014). Despite the recent advances in experimental investigations and the increasing detailed observation by lightning monitoring arrays, many fundamental questions are yet unsolved. In particular, to which extent electrical discharges in volcanic plumes are comparable to thundercloud lightning? Is the presence of hydrometeors in the plume a necessary condition for the generation of volcanic lightning? Multiparametric observation of electrical activity at erupting volcanoes is key to answering these questions. Here we present the results of a campaign of measurements conducted at Sakurajima volcano (southern Japan) where, for the first time, we combined synchronized high-speed imaging with magnetotelluric (MT) and acoustic measurements of ash-rich plumes generating electrical discharges and compare our observations with maximum plume height measurement and atmospheric soundings. Results show that flashes concentrate within the plume and closer to the crater. Good correlation if found between cloud-to-ground versus intra-cloud events and the frequency and duration of recorded MT-signals, while measured currents at Sakurajima are 10 to 100 times smaller than those produced by thundercloud discharges. Finally, atmospheric soundings show that plumes producing flashes didn't cross isotherms relevant for ice formation thus discarding a relevant contribution of hydrometeors in the generation of the observed volcanic lightning. Cimarelli et al. 2014. Experimenal generation of volcanic lightning. Geology v. 42, no. 1 doi: 10.1130/G34802.1

  2. Post-eruptive volcanic dome evolution as revealed by deformation and microgravity observations at Usu volcano (Hokkaido, Japan)

    NASA Astrophysics Data System (ADS)

    Jousset, Philippe; Okada, Hiromu

    1999-04-01

    Usu volcano (Hokkaido, Japan) is a dacitic volcano, known for its high production rate of lava domes and crypto-domes. It is thus a good target to study processes of volcanic dome evolution (upheaval and/or relaxation). We carried out repeated GPS and microgravity surveys on the three most recent domes of Mt. Usu (1910: Meiji Shinzan; 1943-1945: Showa-Shinzan and 1977-1982: Usu-Shinzan). The repeat period was 1 to 2 months and extended from October 1996 to June 1997. We also compare new data with results from former studies. More than 20 years after the start of Usu-Shinzan dome growth, there is still subsidence at a maximum rate of about 7 to 8 cm/year. The reasons for this subsidence are discussed. Repeated gravity surveys revealed an increase of gravity on the domes (about 60±10 microgal/year for Usu-Shinzan, about 15 microgal at Showa-Shinzan and 10 to 20 microgal for Meiji-shinzan); this gravity increase exceeds that expected due to subsidence. We discuss and interpret the excess gravity change in terms of a density increase in the edifice, caused by a combination of processes (contraction of the edifice, water level change, devesiculisation, cooling and magma intrusion). Quantification of these processes at Usu volcano may help to understand the processes of evolution at domes on other volcanoes such as Merapi (Indonesia), Unzen (Japan) or Montserrat (West Indies).

  3. Constraining tephra dispersion and deposition from three subplinian explosions in 2011 at Shinmoedake volcano, Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Maeno, Fukashi; Nagai, Masashi; Nakada, Setsuya; Burden, Rose E.; Engwell, Samantha; Suzuki, Yuki; Kaneko, Takayuki

    2014-06-01

    Constraining physical parameters of tephra dispersion and deposition from explosive volcanic eruptions is a significant challenge, because of both the complexity of the relationship between tephra distribution and distance from the vent and the difficulties associated with direct and comprehensive real-time observations. Three andesitic subplinian explosions in January 2011 at Shinmoedake volcano, Japan, are used as a case study to validate selected empirical and theoretical models using observations and field data. Tephra volumes are estimated using relationships between dispersal area and tephra thickness or mass/area. A new cubic B-spline interpolation method is also examined. Magma discharge rate is estimated using theoretical plume models incorporating the effect of wind. Results are consistent with observed plume heights (6.4-7.3 km above the vent) and eruption durations. Estimated tephra volumes were 15-34 × 106 m3 for explosions on the afternoon of 26 January and morning of 27 January, and 5.0-7.6 × 106 m3 for the afternoon of 27 January; magma discharge rates were in the range 1-2 × 106 kg/s for all three explosions. Clast dispersal models estimated plume height at 7.1 ± 1 km above the vent for each explosion. The three subplinian explosions occurred with approximately 12-h reposes and had similar mass discharge rates and plume heights but decreasing erupted magma volumes and durations.

  4. Overpressurized fluids drive microseismic swarm activity around Mt. Ontake volcano, Japan

    NASA Astrophysics Data System (ADS)

    Terakawa, Toshiko

    2017-06-01

    Microseismic swarm activity has taken place since 1976 around Mt. Ontake, the second highest stratovolcano in Japan. This activity is thought to be linked to high pore-fluid pressure in the vicinity of the volcano. We analyzed well-constrained focal mechanism solutions of microseismicity to re-estimate the 3-D pore-fluid pressure field driving vigorous swarm activity around Mt. Ontake. Pore-fluid pressures were measured by mapping earthquake focal mechanisms on the 3-D Mohr diagram for the regional stress field with high resolutions of 2-5 km. The assumption of the reference stress pattern can cause modeling errors in measurements of pore-fluid pressure. To remove the effect, we statistically evaluated the estimation errors of the regional stress field and included these errors in the analysis. We detected an overpressurized fluid reservoir with a peak of about 10-30 MPa in the east flank of Mt. Ontake, where microseismic swarm activity has been vigorous for the last two decades. The level of pore-fluid pressure was maintained for at least 5 years after 2009. This finding indicates that there are some interactions between the intensive swarm activity and overpressurized fluids: the swarm activity has been driven by overpressurized fluids, whereas pore-fluid pressures have been suppressed by the swarm activity.[Figure not available: see fulltext.

  5. Sequential change in intensity and magma supply of the Hoei eruption, Fuji Volcano, Japan (AD 1707)

    NASA Astrophysics Data System (ADS)

    Mannen, K.; Naomichi, M.

    2010-12-01

    Fuji volcano, which is the most famous mountain in Japan, is also one of the most dangerous volcanoes in the country. The AD 1707 eruption of the volcano, known as Hoei eruption, caused severe damage in the downwind area, including Tokyo and Yokohama approximately 100 km east of the volcano. We reconstructed the sequence and change in mass discharge rate of the Hoei eruption from the detailed correlation between the timelines reestablished from historical documents and geological units. The geological sequence of the eruption is composed of numerous beds, presumably formed by interruptions and fluctuation of the column activity. However, from examination of historical documents, we only detected six obvious quiet intervals from historical documents. We thus defined an eruptive pulse as the period of continuous tephra fall divided by the obvious quiet interval. We then divided the course of the Hoei eruption into 3 stages on the basis of the pattern of eruptive pulses. The characteristics of the three stages are described as follows. Stage I is characterized by the quick firing of two energetic eruptive pulses (≤25 km high column), with each pulse showing intense outburst initially, followed by a decrease in intensity (≤16 km high column). In this stage, silicic magma erupted in the early outburst phases and followed by mild phase of basaltic magma. Stage II consists of discrete firing of basaltic magma, resulting in the formation of a relatively low eruption column (≤15 km high column). Stage III is principally characterized by sustained column activity of basaltic magma without a clear repose time. In stage III, the column height appears to be always above 13 km and in at least three distinct active periods, the column height is presumed to exceed 16 km. The change in magma supply rate is summarized as follows. In initial silicic phase of stage I, the magma supply rate is high (3.3 × 10^11 kg/day), and then lowers to the average of the whole range of the

  6. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people.

    This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features.

    The ASTER instrument is a cooperative project between NASA, JPL, and the Japanese Ministry of International Trade and Industry.

    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-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the

  7. ASTER-SRTM Perspective of Mount Oyama Volcano, Miyake-Jima Island, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Mount Oyama is a 820-meter-high (2,700 feet) volcano on the island of Miyake-Jima, Japan. In late June 2000, a series of earthquakes alerted scientists to possible volcanic activity. On June 27, authorities evacuated 2,600 people, and on July 8 the volcano began erupting and erupted five times over that week. The dark gray blanket covering green vegetation in the image is the ash deposited by prevailing northeasterly winds between July 8 and 17. This island is about 180 kilometers (110 miles) south of Tokyo and is part of the Izu chain of volcanic islands that runs south from the main Japanese island of Honshu. Miyake-Jima is home to 3,800 people. The previous major eruptions of Mount Oyama occurred in 1983 and 1962, when lava flows destroyed hundreds of houses. An earlier eruption in 1940 killed 11 people.

    This image is a perspective view created by combining image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's Terra satellite with an elevation model from the Shuttle Radar Topography Mission (SRTM). Vertical relief is exaggerated, and the image includes cosmetic adjustments to clouds and image color to enhance clarity of terrain features.

    The ASTER instrument is a cooperative project between NASA, JPL, and the Japanese Ministry of International Trade and Industry.

    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-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the

  8. 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

  9. Detection of Aeromagnetic Field Changes Using an Unmanned Autonomous Helicopter: Repeated Experiments at Tarumae Volcano (Japan)

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Koyama, T.; Yanagisawa, T.; Yoshimoto, M.; Ohminato, T.; Kaneko, T.

    2015-12-01

    Volcanic eruptions often prohibit humans from approaching active craters. Meanwhile, it is important, especially at the initial stage of an eruption, to perform visual surveillance, geophysical/chemical measurements and material sampling in the vicinity of the craters. Besides scientific purposes, information from such surveys is helpful for the local government in deciding the response to volcanic unrest. We started airborne surveys using an unmanned helicopter on a trial basis in cooperation with the Hokkaido Regional Development Bureau. As a part of the project, we repeated aeromagnetic surveys over Mt. Tarumae (1,041m), one of the active volcanoes in northern Japan in 2011, 2012 and 2013. Owing to its high accuracy of positioning control in the autonomous flight with the aid of GPS navigation and the fairly small magnetic field gradient in the air, temporal changes up to 30 nT were successfully detected through a direct comparison between separate surveys. The field changes in the air were mostly consistent with those on the ground surface, which suggested remagnetization due to cooling beneath the summit lava dome. Through our three-year experiments, the unmanned helicopter was proved to be useful for aeromagnetic monitoring. Although the system still has some limitations in terms of maximum flight altitude and operational range from the base station, we emphasize the following three advantages of this technique. (1) Operation without exposing human to volcanic hazards. (2) Straightforward data processing procedure to obtain temporal magnetic field changes, which is especially important in an emergency response such as an ongoing unrest. (3) Great reduction of the cost to maintain ground-based monitoring stations for many years. Acknowledgments: We express sincere thanks to Muroran and Sapporo Development and Construction Departments of the HRDB for the cooperation in the field experiments using their unmanned helicopter.

  10. Characterizing Explosive Eruptions at Sakurajima Volcano, Japan, Using Seismic, Infrasound, Lightning and Video Data

    NASA Astrophysics Data System (ADS)

    Smith, C. M.; Behnke, S. A.; Thomas, R. J.; Edens, H. E.; Cimarelli, C.; Cigala, V.; Van Eaton, A. R.; Iguchi, M.; Miki, D.; McNutt, S. R.

    2015-12-01

    The ability to determine volcanic ash plume characteristics from seismic and/or infrasonic records would enable increased accuracy in volcanic monitoring during times of low visibility. During May-June 2015 a field deployment of 6 infrasound sensors, 2 seismometers, multiple cameras, and 10 Lightning Mapping Array (LMA) stations were deployed around Sakurajima Volcano in Japan. During one month of observations (13 May to 10 June) hundreds of explosive eruptions were observed with plume heights reaching 4.3 km above the vent. The plumes varied in duration, ash content, and physical form. The resulting explosions exhibited a variety of infrasound waveforms including the classic long-period N shape as well as events with a mixture of high and low frequencies. For a subset of larger events, peak pressures ranged from 16 to 741 Pa at a distance of 3.6 km from the vent. The seismic signals are long period and emergent with no clear P or S-waves, although high frequency ground-coupled airwaves are visible in conjunction with the infrasonic record of some of the explosive eruptions. Peak ground displacements on the vertical component ranged from 2.1 to 183 um for the same subset of events. Volcanic lightning was both visually observed and recorded on the LMA stations. One of the goals of this project to determine if there are intrinsic relationships between ash plume characteristics, such as initial velocity or acceleration, ash grain size, texture, and composition, seismic and infrasound waveforms, and the presence and type of volcanic lightning. The rich variety of observations provides a good opportunity to determine such relationships.

  11. Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan.

    PubMed

    Uyeda, S; Hayakawa, M; Nagao, T; Molchanov, O; Hattori, K; Orihara, Y; Gotoh, K; Akinaga, Y; Tanaka, H

    2002-05-28

    Significant anomalous changes in the ultra low frequency range (approximately 0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals.

  12. Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

    PubMed Central

    Uyeda, S.; Hayakawa, M.; Nagao, T.; Molchanov, O.; Hattori, K.; Orihara, Y.; Gotoh, K.; Akinaga, Y.; Tanaka, H.

    2002-01-01

    Significant anomalous changes in the ultra low frequency range (≈0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals. PMID:12032286

  13. Application of terrestrial laser scanning for detection of ground surface deformation in small mud volcano (Murono, Japan)

    NASA Astrophysics Data System (ADS)

    Hayakawa, Yuichi S.; Kusumoto, Shigekazu; Matta, Nobuhisa

    2016-07-01

    We perform terrestrial laser scanning (TLS) to detect changes in surface morphology of a mud volcano in Murono, north-central Japan. The study site underwent significant deformation by a strong earthquake in 2011, and the surface deformation has continued in the following years. The point cloud datasets were obtained by TLS at three different times in 2011, 2013 and 2014. Those point clouds were aligned by cloud-based registration, which minimizes the closest point distance of point clouds of unchanged ground features, and the TLS-based point cloud data appear to be suitable for detecting centimeter-order deformations in the central domain of the mud volcano, as well as for measurements of topographic features including cracks of paved ground surface. The spatial patterns and accumulative amount of the vertical deformation during 2011-2014 captured by TLS correspond well with those previously reported based on point-based leveling surveys, supporting the validity of TLS survey.

  14. Increasing of Gas Bubbling at Wariishi Flowing Spring, Central Japan, before and after the 2014 Ontake Volcano Eruption

    NASA Astrophysics Data System (ADS)

    Kimata, F.; Tasaka, S.; Asai, Y.

    2016-12-01

    Wariishi Spa is locating at Atotsugawa active fault, and it is an flowing spring from the 850m depth by the bore hole. The spring is coming from the rain fall through the geological boundary. Discharge was measured 100L/minute by manual every week in 1977. In 1990, measurement system was updated to 1Hz by electromagnetic flowmeter system. Co-seismic discharge rises are measured for about 100 examples of the earthquake occurrence in around area. The discharge rise is decreasing asymptotic convergence with time. In 2011 Tohoku Earthquake, the discharge of spring is a rise of 30 L/minutes, and it took 1 and half year to return to 20 L/minute. Ontake Volcano is one of the active volcanoes in same mountain range, but it is located about 50 km south from the Wariishi spa. There are three active volcanoes between Wariishi Spa and Ontake Volcano. The volcano was erupted in a phreatic explosion on September 27, 2014. There is no observation of the discharge change at the eruption in the hot spring. There are other hot spring systems in Wariishi spa. The spa has a periodic spring with one to two-hour frequencies. The periodic frequencies are depended on the discharge volume. Therefore, at the co-seismic discharge rise, the shortenings of periodic frequencies are observed. Hence, the mechanism of main discharge and periodic spring is located at the depth of 850 m. Based on discussion on time series of discharge spa, there are observed many pulsed noises between the periodic springs. The noises are caused by gas bubbling from the precise examinations. It is suggested that gas bubbling is different mechanism with periodic spring, because no effects on the periodic spring frequency. Bubbling is sourced from more deep than 850 m. Gas bubbling was observed about 50 times between the periodic spa around the Ontake volcano eruption. There is no report on such gas bubbling rise since 2012. Discussed above, it is suggested some changes of strain field at central Japan, especially in

  15. Volcano Observations Using an Unmanned Autonomous Helicopter : seismic and GPS observations near the active summit area of Sakurajima and Kirishima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Takeo, M.; Iguchi, M.; Honda, Y.

    2012-04-01

    Observations in the vicinity of summit area of active volcanoes are very important from various viewpoints such as understanding physical processes in the volcanic conduit. It is, however, highly difficult to install observation sensors near active vents because of the risk of sudden eruptions. We have been developing a safe volcano observation system based on an unmanned aerial vehicle (UAV). As an UAV, we adopted an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. We have also developed earthquake observation modules and GPS receiver modules that are exclusively designed for UAV installation at summit areas of active volcanoes. These modules are light weight, compact size, and solar powered. For data transmission, a commercial cellular-phone network is used. Our first application of the sensor installation by the UAV is Sakurajima, one of the most active volcanos in Japan. In November 2009, 2010, and 2011, we installed up to four seismic sensors within 2km from the active summit crater. In the 2010 and 2011 operations, we succeeded in pulling up and collecting the sensor modules by using the UAV. In the 2011 experiment, we installed two GPS receivers near the summit area of Sakurajima volcano. We also applied the UAV installation to another active volcano, Shinmoedake in Kirishima volcano group. Since the sub-plinian eruption in February 2011, entering the area 3km from the summit of Shinmoe-dake has been prohibited. In May and November 2011, we installed seismic sensors and GPS receivers in the off-limit zone. Although the ground coupling of the seismic modules is not perfect due to the way they are installed, the signal-to-noise ratio of the seismic signals recorded by these modules is fairly good. Despite the low antenna height of 50 cm from the ground surface, the location errors in horizontal and vertical GPS components are 1cm and 3cm, respectively. For seismic signals associated with eruptions at Sakurajima from November 2010 to

  16. Intensive hydration of the wedge mantle at the Kuril arc - NE Japan arc junction: implications from mafic lavas from Usu Volcano, northern Japan

    NASA Astrophysics Data System (ADS)

    Kuritani, T.; Tanaka, M.; Yokoyama, T.; Nakagawa, M.; Matsumoto, A.

    2015-12-01

    The southwestern part of Hokkaido, northern Japan, is located at the junction of the NE Japan arc and the Kuril arc. The subducting Pacific plate under this region shows a hinge-like shape due to the dip change of the subducting plate along the trench. Because of the interest in this unique tectonic setting, this arc-arc junction has been the focus of extensive geophysical studies (e.g. Kita et al., 2010, Morishige and van Keken, 2014; Wada et al., 2015). This region is also known as an area in which magmatism has been intense; there are many active volcanoes such as Usu, Tarumae, and Komagatake, and large calderas including Toya, Shikotsu, and Kuttara. In this region, the temporal and spatial evolution of the volcanism and the chemical compositions of the volcanic rocks are well characterized (e.g. Nakagawa, 1992). However, the generation conditions of magmas have not been estimated for these volcanoes, probably because of the scarcity of basaltic products. Therefore, a possible link between the tectonic setting and the intense magmatism is still unclear. In this study, we carried out a petrological and geochemical study on mafic lavas (49.6-51.3 wt.% SiO2) from Usu Volcano, and estimated the conditions under which the magmas were generated. By application of a plagioclase-melt hygrometer to the plagioclase and the host magma, the water content of ~6.5 wt.% was obtained for the basaltic magma. Using this information, as well as the olivine maximum fractionation model (Tatsumi et al., 1983), the composition of the primary magma is estimated to be 47.9 wt.% SiO2, 15.1 wt.% MgO, and 4.1 wt.% H2O. Analyses using the multi-component thermodynamics suggest that the primary magma was generated in the source mantle with 0.9 wt.% H2O at 1310ºC and at 1.6 GPa. The water content of 0.9 wt.% of the source mantle is significantly higher than the estimates for the source mantle in the main NE Japan arc (<0.7 wt.% H2O); this implies that the flux of slab-derived fluids is

  17. Magma reservoir conditions beneath Tsurumi volcano, SW Japan: Evidence from amphibole thermobarometry and seismicity

    NASA Astrophysics Data System (ADS)

    Nagasaki, Shiho; Ishibashi, Hidemi; Suwa, Yukiko; Yasuda, Atsushi; Hokanishi, Natsumi; Ohkura, Takahiro; Takemura, Keiji

    2017-05-01

    Calcic amphibole phenocrysts in the Tsurumidake summit (TS) lava, which was produced during the most recent eruption at Tsurumi Volcano (SW Japan) at around 7.5-10.5 ka, have been analyzed to determine the pre-eruptive conditions, such as temperature (T), pressure (P), oxygen fugacity (fO2), SiO2 content (SiO2melt), and FeO*/MgO ratio (FeO*/MgOmelt), of coexisting silicate melts in the magma reservoir beneath the volcano. Although most of the amphibole phenocrysts have been completely decomposed to a fine-grained opaque symplectite, 6% of the grains remain intact. The degree of amphibole breakdown (DAB), defined as the ratio of the area of symplectite to the area of symplectite plus relict amphibole in each phenocryst, varies from 20% to 100%. Compositional zoning was not observed in the amphibole grains, however, two distinct groups of amphibole phenocrysts have been identified based on their chemical compositions: group-I amphiboles, which are relatively Si-poor, and [6]Al-rich, and have a relatively high Mg# [100Mg/(Mg + Fe2 +)]; and group-II amphiboles, which are Si-rich, and [6]Al-poor, and have a relatively low Mg#. Empirical equations for geothermobarometry, oxygen barometry and chemometry that exclusively rely on the amphibole composition were applied to estimate the T-P-fO2-SiO2melt-FeO*/MgOmelt conditions of the silicate melts with which the amphibole crystals equilibrated. The results show that group-I and group-II amphiboles equilibrated with andesitic melts (group-I melts) and dacitic-rhyolitic melts (group-II melts), respectively. The T-P-fO2 conditions of group-I melts were estimated as 374-483 MPa ( 13.9-17.9 km depth), 950 °C, and NNO + 1.3, respectively, and those of group-II melts were 93-242 MPa ( 3.4-9.0 km depth), 824-913 °C, and NNO + 0.6-1.7, respectively. The estimated T-P-fO2-SiO2melt-FeO*/MgOmelt conditions were almost constant for group-I melts, whereas the T, ΔNNO, and FeO*/MgOmelt values of group-II melts decreased with increasing

  18. The effect of porosity and crystallinity on magma rheology at Unzen volcano, Japan

    NASA Astrophysics Data System (ADS)

    Coats, Rebecca; Lavallée, Yan; Kendrick, Jackie E.; Wallace, Paul A.; Ashworth, James D.; Hornby, Adrian; Miwa, Takahiro

    2016-04-01

    Eruptions of lava domes are some of the most unpredictable and dangerous volcanic phenomena, and their frequent occurrence highlights the priority of improving our understanding of the mechanisms at play during magma ascent. For example, between 1991 and 1995 Mt. Unzen sustained an extensive period of dome growth. During this time approximately 2.1x108 m3 dense rock equivalent of magma was emplaced at effusion rates of 0.1-4x105 m3d-1. Repeated partial collapses of the dome generated frequent pyroclastic density currents which caused several fatalities and damage to populated areas near Shimabara City. One of the keys to grasping the switch between effusive to explosive behaviour, as well as the onset of a dome collapse event lies within understanding the rheological behaviour of upwelling magma. Although the conditions which lead to failure of magma are now increasingly studied, we lack an understanding of the influence of mechanisms at play during magma deformation. Strain rate and temperature play primary roles in the transition of silicate melts from viscous bodies to elastic solids; this regime change is known as the viscous-brittle transition and is bound by the glass transition of the interstitial melt, which signals the beginning of either fracture or flow. Crystals and pores present in the system can alter the position of the viscous-brittle transition. Laboratory experiments which aim to simulate realistic volcanic conditions permit the controlled study of volcanic processes, and help determine the behaviour of multi-phase magmatic suspensions. For magma with high crystal contents (>40%) rheology is strongly influenced by the crystalline phase and is strain rate dependent. Here we present the results of high-temperature deformation experiments on variably porous (9-33%), crystal-rich (>50%) dacite lavas from Unzen volcano, Japan. Uniaxial compression tests were carried out on dacitic samples from Unzen at room temperature (˜20° C) and high temperature

  19. Diffuse CO_{2} and ^{222}Rn degassing monitoring of Ontake volcano, Japan

    NASA Astrophysics Data System (ADS)

    Alonso, Mar; Sagiya, Takeshi; Meneses-Gutiérrez, Ángela; Padrón, Eleazar; Hernández, Pedro A.; Pérez, Nemesio M.; Melián, Gladys; Padilla, Germán D.

    2017-04-01

    Mt. Ontake (3067 m.a.s.l.) is a stratovolcano located in central Honsu and around 100 Km northeast of Nagoya, Japan, with the last eruption occurring on September 27, 2014, killing 57 people, and creating a 7-10 km high ash plume (Kagoshima et. al., 2016). There were no significant earthquakes that might have warned authorities in the lead up to the phreatic eruption, caused by ground water flashing to steam in a hydrothermal explosion. At the time of the eruption there was no operational geochemical surveillance program. In order to contribute to the strengthening of this program, the Disaster Mitigation Research Center of Nagoya University and the Volcanological Institute of Canary Islands started a collaborative program. To do so, an automatic geochemical station was installed at Ontake volcano and a survey of diffuse CO2efflux and other volatiles was carried out at the surface environment of selected areas of the volcano. The station was installed 10.9 km east away from the eruptive vent, where some earthquakes occurred, and consists of a soil radon (Rn) monitor (SARAD RTM-2010-2) able to measure 222Rn and 220Rn activities. Monitoring of radon is an important geochemical tool to forecast earthquakes and volcanic eruptions due to its geochemical properties. Rn ascends from the lower to the upper part of earth's crust mainly through cracks or faults and its transport needs the existence of a naturally occurring flux of a carrier gas. Regarding to the soil gas survey, it was carried out in August 2016 with 183 measurement points performed in an area of 136 km2. Measurements of soil CO2 efflux were carried out following the accumulation chamber method by means of a portable soil CO2 efflux instrument. To estimate the total CO2 output, sequential Gaussian simulation (sGs) was used allowing the interpolation of the measured variable at not-sampled sites and assess the uncertainly of the total diffuse emission of carbon dioxide estimated for the entire studied area

  20. Permeability evolution governed by shear: An example during spine extrusion at Unzen volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ashworth, James; Lavallée, Yan; Wallace, Paul; Kendrick, Jackie; Coats, Rebecca; Miwa, Takahiro; Hess, Kai-Uwe

    2017-04-01

    A volcano's eruptive style is strongly controlled by the permeability of the magma and the surrounding edifice rock - explosive activity is more likely if exsolved gases cannot escape the system. In this study, we investigate how shear strain causes variations in permeability within a volcanic conduit, and discuss how spatio-temporal variation in shear regimes may develop. The eruption of Unzen volcano, Japan, which occurred between 1990 - 1995, culminated in the extrusion of a 60 metre-high dacitic spine. The spine, left exposed at the lava dome surface, displays the petrographic architecture of the magma in the shallow conduit. Observations and measurements made in the field are combined with laboratory experiments to understand the distribution of permeability in the shallow conduit. Examination of the lava dome led to the selection of two sites for detailed investigation. First, we examined a section of extruded spine 6 metres in width, which displays a transition from apparently unsheared rock in the conduit core to rocks exhibiting increasing shear towards the conduit margin, bounded by a fault gouge zone. Laboratory characterisation (mineralogy, porosity, permeability, X-ray tomography) was undertaken on these samples. In contrast, a second section of spine (extruded later during the eruption) exhibited a large tensile fracture, and this area was investigated using non-destructive in-situ permeability measurements. Our lab measurements show that in the first outcrop, permeability decreases across the shear zone from core to gouge by approximately one order of magnitude perpendicular to shear; a similar decrease is observed parallel to shear, but is less severe. The lowest permeability is observed in the most highly sheared block; here, permeability is 2.5 x10-14 m2 in the plane of shear and 9 x10-15 m2 perpendicular to shear. Our measurements clearly demonstrate the influence of shear on conduit permeability, with significant anisotropy in the shear zone

  1. Crustal deformation and volcanic earthquakes associated with the recent volcanic activity of Iwojima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ueda, H.; Fujita, E.; Tanada, T.

    2013-12-01

    Iwojima is an active volcanic island located within a 10 km wide submarine caldera about 1250 km to the south of Tokyo, Japan. The seismometer and GPS network of National Research Institute for Earth Science and Disaster Prevention (NIED) in Iwojima has observed a repeating island wide uplift more than 1 m associated with large number of volcanic earthquakes every several years. During 2006-2012, we observed more than 20000 volcanic earthquakes and an uplift of about 3 m, and precursory volcanic earthquakes and rapid crustal deformation just before the small submarine eruption near the northern coast of Iwojima in April 2012. In a restless volcano such as Iwojima, it is important issue to distinguish whether rapid crustal deformation and intense earthquake activity lead to an eruption or not. According to a long period geodetic observation by Ukawa et al. (2006), the crustal deformation of Iwojima can be classify into 2 phases. The first is an island wide large uplift centering on Motoyama area (the eastern part of the island, the center of the caldera), and the second is contraction and subsidence at local area centering on Motoyama and uplift around that area. They are interpreted by superposition of crustal deformations by a shallow contraction source and a deep seated inflation source beneath Motoyama. The earthquake activity of Iwojima highly correlates with the island wide large uplift, suggesting the earthquakes are almost controlled by a magma accumulation into a deep seated magma chamber. In contrast to the activity, the precursory activity of the eruption in 2012 is deviated from the correlation. The rapid crustal deformation just before and after the eruption in 2012 can be interpreted by rapid inflation and deflation of a shallow sill source about 1km deep, respectively, suggesting that it was caused by a shallow hydrothermal activity. The result shows that we can probably distinguish an abnormal activity related with a volcanic eruption when we observe

  2. Evolution of magma feeding system in Kumanodake agglutinate activity, Zao Volcano, northeastern Japan

    NASA Astrophysics Data System (ADS)

    Takebe, Yoshinori; Ban, Masao

    2015-10-01

    The Kumanodake agglutinate of Zao Volcano in northeastern Japan consists of pyroclastic surge layers accumulated during the early part of the newest stage of activity (ca. 33 ka to present). Our petrologic study of this agglutinate based on systematically collected samples aims to reveal the evolution of magma feeding system. To understand the magma evolution, we have examined samples from the agglutinate by using petrologic data including, petrography, analysis of minerals (plagioclase, pyroxene, and olivine), glass compositions, and whole rock major element and trace element (Ba, Sr, Cr, Ni, V, Rb, Zr, Nb, and Y) compositions. Agglutinate are mixed, medium-K, calc-alkaline olv-cpx-opx basaltic andesite (55.2-56.2% SiO2). Results show that the magma feeding system comprised a shallow felsic chamber injected by mafic magma from depth. The felsic magma (59-62% SiO2, 950-990 °C), which was stored at a shallower depth, had orthopyroxene (Mg# = 60-69), clinopyroxene (Mg# = 65-71), and low-An plagioclase (Anca. 58-70). The mafic magma is further divisible into two types: less-differentiated and more-differentiated, designed respectively as an initial mafic magma-1 and a second mafic magma-2. The original mafic magma-1 was olivine (Fo 84) basalt (ca. 48-51% SiO2, 1110-1140 °C). The second mafic magma-2, stored occasionally at 4-6 km depth, was basalt (1070-1110 °C) having Foca. 80 olivine and high-An (Anca. 90) plagioclase phenocrysts. These two magmas mixed (first mixing) to form hybrid mafic magma. The forced injections of the hybrid mafic magmas activated the felsic magma, and these two were mixed (second mixing) shortly before eruptions. The explosivity is inferred to have increased over time because the abundance of large scoria increased. Furthermore, the erupted magma composition became more mafic, which reflects increased percentage of the hybrid mafic magma involved in the second mixing. At the beginning of activity, the mafic magma also acted as a heat

  3. Physical properties of volcanic lightning: Constraints from magnetotelluric and video observations at Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Aizawa, Koki; Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel A.; Yokoo, Akihiko; Dingwell, Donald B.; Iguchi, Masato

    2016-06-01

    The lightning generated by explosive volcanic eruptions is of interest not only as a promising technique for monitoring volcanic activity, but also for its broader implications and possible role in the origin of life on Earth, and its impact on the atmosphere and biosphere of the planet. However, at present the genetic mechanisms and physical properties of volcanic lightning remain poorly understood, as compared to our understanding of thundercloud lightning. Here, we present joint magnetotelluric (MT) data and video imagery that were used to investigate the physical properties of electrical discharges generated during explosive activity at Sakurajima volcano, Japan, and we compare these data with the characteristics of thundercloud lightning. Using two weeks of high-sensitivity, high-sample-rate MT data recorded in 2013, we detected weak electromagnetic signals radiated by volcanic lightning close to the crater. By carefully inspecting all MT waveforms that synchronized with visible flashes, and comparing with high-speed (3000 frame/s) and normal-speed (30 frame/s) videos, we identified two types of discharges. The first type consists of impulses (Type A) and is interpreted as cloud-to-ground (CG) lightning. The second type is characterized by weak electromagnetic variations with multiple peaks (Type B), and is interpreted as intra-cloud (IC) lightning. In addition, we observed a hybrid MT event wherein a continuous weak current accompanied Type A discharge. The observed features of volcanic lightning are similar to thunderstorm lightning, and the physical characteristics show that volcanic lightning can be treated as a miniature version of thunderstorm lightning in many respects. The overall duration, length, inter-stroke interval, peak current, and charge transfer all exhibit values 1-2 orders of magnitude smaller than those of thunderstorm lightning, thus suggesting a scaling relation between volcanic and thunderstorm lightning parameters that is independent of

  4. Distinct S wave reflector in the midcrust beneath Nikko-Shirane volcano in the northeastern Japan arc

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Hasegawa, Akira

    1996-02-01

    Distinct S waves reflected from a midcrustal seismic velocity discontinuity are detected beneath Nikko-Shirane volcano in the southernmost part of the northeastern Japan arc. A detailed travel time analysis of the reflected S waves by using data acquired through a dense seismic network temporarily set up in this region shows that this unusual S wave reflector is distributed over an area of 15 × 15 km2 at depths ranging from 8 to 15 km. The reflector has a conical shape becoming shallow toward the summit of Nikko-Shirane volcano. Observed amplitude spectral ratios of reflected S waves to direct S waves show that the reflector body has a strong velocity contrast to the surrounding medium and its thickness is of the order of 100 m at most. The reflector body is approximated by two thin layers probably filled with partially molten materials. Cutoff depth for shallow seismicity in this area is 3-5 km above the reflector and becomes shallow toward Nikko-Shirane volcano, nearly parallel to the reflector. The depth to brittle-ductile transition zone seems to be prescribed by the existence of the reflector body, which is perhaps a thin magma body.

  5. Characterization of the luminance and shape of ash particles at Sakurajima volcano, Japan, using CCD camera images

    NASA Astrophysics Data System (ADS)

    Miwa, Takahiro; Shimano, Taketo; Nishimura, Takeshi

    2015-01-01

    We develop a new method for characterizing the properties of volcanic ash at the Sakurajima volcano, Japan, based on automatic processing of CCD camera images. Volcanic ash is studied in terms of both luminance and particle shape. A monochromatic CCD camera coupled with a stereomicroscope is used to acquire digital images through three filters that pass red, green, or blue light. On single ash particles, we measure the apparent luminance, corresponding to 256 tones for each color (red, green, and blue) for each pixel occupied by ash particles in the image, and the average and standard deviation of the luminance. The outline of each ash particle is captured from a digital image taken under transmitted light through a polarizing plate. Also, we define a new quasi-fractal dimension ( D qf ) to quantify the complexity of the ash particle outlines. We examine two ash samples, each including about 1000 particles, which were erupted from the Showa crater of the Sakurajima volcano, Japan, on February 09, 2009 and January 13, 2010. The apparent luminance of each ash particle shows a lognormal distribution. The average luminance of the ash particles erupted in 2009 is higher than that of those erupted in 2010, which is in good agreement with the results obtained from component analysis under a binocular microscope (i.e., the number fraction of dark juvenile particles is lower for the 2009 sample). The standard deviations of apparent luminance have two peaks in the histogram, and the quasi-fractal dimensions show different frequency distributions between the two samples. These features are not recognized in the results of conventional qualitative classification criteria or the sphericity of the particle outlines. Our method can characterize and distinguish ash samples, even for ash particles that have gradual property changes, and is complementary to component analysis. This method also enables the relatively fast and systematic analysis of ash samples that is required for

  6. Uplift revealed by LASER scanner surveys in Murono mud volcano, Niigata Prefecture, Japan, and estimation of its source

    NASA Astrophysics Data System (ADS)

    Takahashi, A.; Fukuda, Y.; Kusumoto, S.

    2014-12-01

    Since mud volcanoes spew out pressurized material, such as natural gas, oil, mud including water from a deeper ground, the activities of the mud volcanoes are good indicators of the stress conditions/orientations as well as the tectonic controls. The Murono mud volcano area located in Tokamachi City, Niigata prefecture, Japan, is one of the active ground deforming areas associated with mud, natural gas, oil and water eruptions. This area is famous because rapid ground deformation events were recorded corresponding to neighboring large earthquakes. For instance, associated with Naganoken-Hokubu Earthquake (Mw. 6.7) which occurred in 2011, the area recorded a sudden large uplift of about 50 cm. In order to reveal the source mechanism of the mud volcano, Toyama University has been conducting successive leveling surveys at 61 benchmarks. They revealed that the same area of the rapid uplift of 2011 has been still uplifting, even the amount of the uplift is much smaller (20 mm/yr). However, the source of the uplift could not be well identified due to the low spatial resolutions. Therefore, in order to obtain a high resolution land deformation pattern, we have conducted laser scanning surveys two times in June and October 2013, using TOPCON Imaging Station IS-301, which can obtain 3D point cloud data by the automatic laser scanning mode without reflector. The surface deformations obtained by comparing the June and October datasets indicate clear uplifts where the sudden uplift occurred. Since the uplift area show a clear concentric pattern, we estimated the source of the uplift assuming a Mogi source model. The obtained source parameters are, depth=14[m], Volume=14[m3], assuming the Poisson's ratio of 0.25. Then the calculated uplift at the nearest benchmark also shows good agreement with the uplift obtained by the leveling survey. The current uplift is much smaller than the 2011 uplift. Nevertheless both sources could be the same, because the areas of the uplifts are

  7. Relationship between geomorphology and lithotypes of lahar deposit from Chokai volcano, Japan

    NASA Astrophysics Data System (ADS)

    Minami, Y.; Ohba, T.; Hayashi, S.; Kataoka, K.

    2013-12-01

    Chokai volcano, located in the northern Honshu arc in Japan, is an andesitic stratovolcano that collapsed partly at ca. 2500 years ago. A post collapse lahar deposit (Shirayukigawa lahar deposit) is distributed in the northern foot of the volcanic edifice. The deposit consists of 16 units of debris flow, hyperconcentrated flow and streamflow deposits. The Shirayukigawa lahar deposit has a total thickness of 30 m and overlies the 2.5-ka Kisakata debris avalanche deposit. Shirayukigawa lahar deposit forms volcanic fan and volcanic apron. The volcanic fan is subdivided into four areas on the basis of slope angles and of geomorphological features: 1) steeply sloped area, 2) moderately sloped area, 3) gently sloped area and 4) horizontal area. From sedimentary facies and structures, each unit of the Shirayukigawa lahar deposit is classified into one of four lithotypes: clast-supported debris flow deposit (Cc), matrix-supported debris flow deposit (Cm1), hyperconcentrated flow deposit (Cm2) and streamflow deposit (Sl). Each type has the following lithological characteristics. The lithotypes are well correlated with the geomorphology of the volcanic fan. The steeply-sloped and the moderately-sloped areas are dominated by Cc, Cm1, and Cm2, and The horizontal area are dominated by Sl. Debris flow deposit (Cc) is massive, very poorly sorted, partly graded, and clast-supported with polymictic clasts dominated by subrounded to rounded volcanic clasts. Matrix is sandy to muddy. Preferred clast orientation are present. Debris flow deposit (Cm1) is massive, very poorly sorted, and matrix-supported with polymictic clasts dominated by subrounded to rounded volcanic clasts. Matrix is sandy to muddy. Some layers exhibit coarse-tail normal/inverse grading. Most clasts are oriented. Hyperconcentrated flow deposit (Cm2) is massive to diffusely laminated, very poorly sorted and matrix-supported with polymictic clasts dominated by subrounded to rounded volcanic rocks. Matrix is sandy. The

  8. Monitoring Quiescent Volcanoes by Diffuse CO2 Degassing: Case Study of Mt. Fuji, Japan

    NASA Astrophysics Data System (ADS)

    Notsu, Kenji; Mori, Toshiya; Vale, Sandie Chanchah Do; Kagi, Hiroyuki; Ito, Takamori

    2006-04-01

    Since the 8th century, more than seventeen eruptions have been recorded for the Mt. Fuji volcano, with the most recent eruption occurring in 1707 (Hoei eruption). For the past 300 years the volcano has been in a quiescent stage and, since the early 1960s, has exhibited neither fumarolic nor thermal activity. However, the number of low-frequency earthquakes with a hypocentral depth of 10 20 km increased significantly beneath the northeastern flank of Mt. Fuji in 2000 2001, suggesting a possible resumption of magmatic activity. In this study, diffuse CO2 efflux and thermal surveys were carried out in four areas of the volcano in 2001 2002 in order to detect possible signs of the upward movement of deep magma. At all survey points, the CO2 efflux was below the detection limit with the exception of a few points with biological CO2 emission, and ground temperatures at a depth of 20 30 cm were below ambient, indicating no surface manifestations of gas or heat emission. Should magma rise into the subsurface, the diffuse CO2 efflux would be expected to increase, particularly along the tectonically weakened lineation on the Mt. Fuji volcano, allowing for the early detection of pre-eruptive degassing.

  9. Results of SO222; Pore fluid chemistry of the Kumano Basin mud volcanoes, Japan

    NASA Astrophysics Data System (ADS)

    Tryon, M. D.; Kopf, A.; Madison, M. J.

    2012-12-01

    The primary hypotheses driving the MeMo Project at the mud volcanoes of the Kumano Basin, arcward of the NanTroSEIZE IODP drilling transect, are: 1) Much, if not most, of the chemically bound water released from depths corresponding to the transition from aseismic to seismogenic behavior are being transported via the subduction factory's intermediate loop, i.e., upwards through the wedge via faults and the fractured upper plate, and 2), the Kumano Basin mud volcanoes tap these fluids and may provide insights on fluid genesis and pathways within the Nankai forearc. During RV Sonne cruise SO222 (Jun-Jul 2012) we collected 600+ pore fluid samples from 6 MeBo drill cores (up to 35 mbsf) and 39 gravity cores (up to 8 mbsf). With few exceptions, the cores from mud volcanoes indicate two trends of fluid freshening with depth; a shallow freshening trend and a deeper freshening trend. Our initial thoughts on this is that the large amount of shallow freshening in the gravity cores is due to gas hydrate dissociation during core recovery and processing, and the deeper freshening trend may be due to advection of fluids influence by mineral dehydration at great depth. At this point, the fluids have just arrived back at the lab and further analyses are about to begin. We will report here on the initial results and present preliminary thoughts on the genesis of the fluids being emitted at the mud volcanoes.

  10. Pre-eruptive inflation caused by gas accumulation: Insight from detailed gas flux variation at Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Kazahaya, Ryunosuke; Shinohara, Hiroshi; Mori, Toshiya; Iguchi, Masato; Yokoo, Akihiko

    2016-11-01

    Sulfur dioxide (SO2) emission rate observations were made at Sakurajima volcano, Japan, to quantify the relationship between the SO2 emission rate and inflation prior to Vulcanian explosions. The explosions associated with precursory inflation events were preceded by decreases in SO2 emission rates by 10-60 min. The amounts of accumulated gas were calculated using time series of SO2 emission rate. The amounts of accumulated SO2 and increases in strain records before the explosions showed a positive correlation. The volume increase of a deformation source calculated using the strain records was of the comparable order of magnitude as the volume of the accumulated volcanic gas. The results suggest that the inflations before the explosions were caused by the gas accumulation.

  11. Explosive eruptive activity and temporal magmatic changes at Yotei Volcano during the last 50,000 years, southwest Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Uesawa, Shimpei; Nakagawa, Mitsuhiro; Umetsu, Akane

    2016-10-01

    To understand the eruptive history, structure, and magmatic evolution of Yotei Volcano, southwest Hokkaido, Japan, we investigated the geology and petrology of tephras located around the base of the volcano. We identified 43 tephra units interbedded with soils (in descending stratigraphic order, tephras Y1-Y43), and four widespread regional tephras. Ten radiocarbon ages were obtained from soils beneath the Yotei tephras. On the basis of petrologic differences and, the stratigraphic positions of thick layers of volcanic ash soil, indicative of volcanic stratigraphic gaps, the Yotei tephras are divided into four groups (in ascending stratigraphic order): Yotei tephra groups I, II-1, II-2, and II-3. We calculated the age of each eruptive deposit based on the soil accumulation rate, and estimated the volume of each eruption using isopach maps or the correlation between eruption volume and the maximum thickness at ~ 10 km from the summit crater. The results regarding eruptive activity and the rate of explosive eruptions indicate four eruptive stages at Yotei Volcano over the last 50,000 years. Stage I eruptions produced Yotei tephra group I between ca. 54 cal. ka BP and up to at least ca. 46 cal. ka BP, at relatively high average eruption rates of 0.07 km3 dense-rock equivalent (DRE)/ky. After a pause in activity of ca. 8000 years, Stage II-1 to II-2 eruptions produced Yotei tephra groups II-1 and II-2 from ca. 38 to ca. 21 cal. ka BP at high average eruption rates (0.10 km3 DRE/ky), after a pause in activity of 2000-3000 years. Finally, after another pause in activity of 4000-5000 years, Stage II-3 eruptions produced Yotei tephra group II-3 from ca. 16.5 cal. ka BP until the present day, at low average eruption rates (0.009 km3 DRE/ky). Whole-rock geochemical compositions vary within each tephra group over the entire eruption history. For example, group I and II-3 tephras contain the lowest and highest abundances, respectively, of K2O, P2O5, and Zr. Group II-1 has the

  12. Low to negligible BrO/SO2 ratios at two subduction-zone volcanoes

    NASA Astrophysics Data System (ADS)

    Bobrowski, Nicole; Hörmann, Christoph; Mori, Toshiya; Platt, Ulrich

    2014-05-01

    In July 2013 a measurement campaign took place on Kyushu, Japan, investigating the BrO/SO2 ratio in the plume of Sakurajima and Aso. Multi-Axis-Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were carried out at four sides on Sakurajima Island, with a maximum distance of about 5 km downwind, and assuming a wind speed of 5 m/s (corresponding to a plume age of about 15 minutes). At Aso measurements took place on the western slope of the active crater and at the crater rim. The MAX-DOAS data of both sites were evaluated for BrO and SO2 slant column densities (SCDs). In the following, BrO/SO2 ratios were calculated to overcome dilution effects and to investigate the BrO formation processes in the ash-laden plume of Sakurajima and the volcanic plume of Aso which is characterized by emissions from a fumarolic area and a mud pool. The BrO/SO2 ratios of the measurement have been below the detection limit for Aso as well as during most of the measurement days at Sakurajima with the only exception on 15th July 2013, when a BrO/SO2 ratio of ~ 1 x 10-5 could be determined. After very high BrO/SO2 ratios at Sakurajima that were reported by C. Lee et al. (2005) our results seem to be unexpected but nevertheless match the general geological settings at both volcanoes. In a recent paper, Shinohara (2013) summarized and compared chlorine emissions from the Japanese volcanic arc with global chlorine emissions from arc volcanoes and pointed out that the volcanic gas emissions in Japan are quite Cl-poor compared to those at other subduction zones. In the recent past it has been found that low chlorine emissions can occur together with nevertheless high bromine emissions (Nyiragongo, Bobrowski et al., 2013). However, looking up Br/Cl ratios (of condensate measurements at fumaroles) of the Japanese arc volcanism summarized in Gerlach, 2004 a comparatively low Br/Cl ratio is added with 6-7 x 10-4 (global arc mean 2 x 10-3) to the already poor chlorine emissions. We

  13. Effects of the 2016 Kumamoto earthquakes on the Aso volcanic edifice

    NASA Astrophysics Data System (ADS)

    Tajima, Yasuhisa; Hasenaka, Toshiaki; Torii, Masayuki

    2017-05-01

    Large earthquakes occurred in the central part of Kumamoto Prefecture on April 14-16, 2016, causing severe damage to the northern segment of the Hinagu faults and the eastern segment of the Futagawa faults. Earthquake surface ruptures appeared along these faults and on the Aso volcanic edifice, which in turn generated landslides. We conducted landform change analysis of the central cones of Aso volcano by using satellite and aerial photographs. First, we categorized the topographical changes as surface scarps, arc-shaped cracks, and linear cracks. Field survey indicated that landslides caused the scarps and arc-shaped cracks, whereas faulting caused the linear cracks. We discovered a surface rupture concentration zone (RCZ) formed three ruptures bands with many surface ruptures and landslides extending from the west foot to the center of the Aso volcanic edifice. The magmatic volcanic vents that formed during the past 10,000 years are located along the north margin of the RCZ. Moreover, the distribution and dip of the core of rupture concentration zone correspond with the Nakadake craters. We conclude that a strong relationship exists between the volcanic vents and fault structures in the central cones of Aso volcano.[Figure not available: see fulltext.

  14. Mercury distribution in seawater of Kagoshima Bay near the active Volcano, Mt. Sakurajima in Japan.

    PubMed

    Ando, Tetsuo; Yamamoto, Megumi; Tomiyasu, Takashi; Tsuji, Mayumi; Akiba, Suminori

    2010-04-01

    Kagoshima bay has a highly active volcano in its center. In the filtered seawater and suspended matter collected from 200-m deep fumaroles at the bottom of the inner bay, the geometric mean concentrations of total mercury were 7.6 and 65.0 ng/L, respectively. The surface seawater collected at the inner bay had a higher concentration of mercury when compared to that in the bay entrance (average: 1.0 vs. 0.5 ng/L). In July, however, no such difference was observed. The fumaroles seem to contribute to relatively high concentrations of mercury in the inner bay except in summer, when thermal cline is formed.

  15. Monitoring of volcanic gas composition at Asama volcano, Japan, during 2004-2014

    NASA Astrophysics Data System (ADS)

    Shinohara, Hiroshi; Ohminato, Takao; Takeo, Minoru; Tsuji, Hiroshi; Kazahaya, Ryunosuke

    2015-09-01

    The composition of the volcanic gases discharged from the summit crater of Asama volcano has been monitored since 2004 by Multi-GAS and alkaline-filter techniques. The persistent degassing activity at Asama volcano is characterized by large variation of SO2 flux. The CO2/SO2 and H2O/SO2 ratios did not show clear variation irrespective of the SO2 flux variation and a few eruptions that occurred during active degassing periods. The estimated ratios have large uncertainty due to variable contribution of the different fumaroles in the summit crater to the volcanic plume and lack of a systematic variation can be due to the large uncertainty. The SO2/Cl ratio showed a systematic decrease after the eruption to the inactive period, suggesting that degassing pressure did not significantly increase after the eruption. Low-pressure degassing along with the continuous and intensive gas discharge suggests that the degassing is due to conduit magma convection. The apparently stable CO2/SO2 ratios imply a lack of significant volatile differentiation in the magma reservoir, such as CO2-rich bubble accumulation. The large variation of the SO2 flux along with stable gas composition implies that the large changes in magma convection rate are caused by changes in the radius of the convecting magma conduit.

  16. Multi-parametric observation of volcanic lightning produced by ash-rich plumes at Sakurajima volcano, Japan.

    NASA Astrophysics Data System (ADS)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Aizawa, Koki; Scheu, Bettina; Yokoo, Akihiko; Mueller, Sebastian; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes are very often associated with electrical discharges producing a majestic display of volcanic lightning. While the direct threat posed by volcanic lightning is small in comparison to other hazards, observation and understanding of this phenomenon can shed light on important properties of the plume such as mass eruption rate and content of fine particles as recently demonstrated by laboratory investigation of volcanic lightning (Cimarelli et al., 2014). Electrical charging of ash particles within the plume can in addition play an important role in aggregation processes therefore influencing the dispersion and sedimentation of tephra. Despite the recent advances in the experimental investigations under controlled conditions and the increasing detailed observation by lightning monitoring arrays, many fundamental questions about electrical discharges in volcanic plume still remain unsolved. In particular, to which extent electrical discharges in volcanic plumes are comparable to thundercloud lightning? Is the presence of hydrometeors in the plume a necessary condition for the generation of volcanic lightning? Answering these questions is vital for the thorough understanding of the electrification process and in turn it is fundamental to fully decipher what volcanic lightning can tell us about the properties of volcanic plumes. The combination of multiparametric observation of electrical activity at erupting volcanoes can undoubtedly help us answering these questions. Here we present preliminary results from a campaign of measurements conducted at Sakurajima volcano in Japan where we combined high-speed imaging with magnetotelluric and acoustic measurements of ash-rich plumes generating electrical discharges and compare our observation with maximum plume height measurement and atmospheric soundings. We invite discussions on cross-correlation of relevant monitoring techniques and possible future developments of multi-parametric arrays. Cimarelli

  17. Temporal changes in thermal waters related to volcanic activity of Tokachidake Volcano, Japan: implications for forecasting future eruptions

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryo; Shibata, Tomo; Murayama, Yasuji; Ogino, Tagiru; Okazaki, Noritoshi

    2015-01-01

    In order to detect changes in volcanic activity of Tokachidake Volcano, Japan, we have continuously monitored thermal waters discharging at the western to southwestern flank of the volcano since 1986. The steam-heated waters in the Nukkakushi crater discharged with boiling temperature until 2002. Thermal waters at the Tokachidake spa area have similar compositions to fumarolic gas emitted from the summit craters, indicating that the waters formed by absorption of volcanic gas into shallow aquifers. Thermal waters at the Fukiage spa area were derived from the same aquifer as the Tokachidake spa area until early 1986. However, after that time, NaCl-type thermal water entered the Fukiage spa area during the increase in volcanic activity associated with the 1988-1989 eruption, thus leading to a clear increase in Cl concentrations and temperature. After the eruption, the supply of the NaCl-type thermal water was halted, and the Cl concentrations of the thermal waters decreased. In contrast, SO4 concentrations gradually increased in the Fukiage spa area after 1989, and the temperature has been maintained. These observations indicate that SO4-rich thermal water with a relatively high temperature entered the system instead of the NaCl-type thermal water. As was the case for the 1988-1989 eruption, the Cl concentrations at the Fukiage spa area increased in 2012 during an increase in volcanic activity, implying that the supply of the NaCl-type thermal water had resumed. However, the chemical changes in the thermal waters since 2012 are small compared with those before the 1988-1989 eruption, with oxygen and hydrogen isotopic compositions remaining nearly the same as those of meteoric waters.

  18. Separation of scattering and intrinsic attenuation at Asama volcano (Japan): Evidence of high volcanic structural contrasts

    NASA Astrophysics Data System (ADS)

    Prudencio, Janire; Aoki, Yosuke; Takeo, Minoru; Ibáñez, Jesús M.; Del Pezzo, Edoardo; Song, WenZhan

    2017-03-01

    In this study we show 2D intrinsic- and scattering-Q images of Asama volcano obtained by analyzing 2320 waveforms from active data. Observed energy envelopes were fitted to the diffusion model and separate intrinsic- and scattering-Q images were produced using a back-projection method based on a Gaussian-type weighting function. Synthetic tests indicate robustness and reliability of the results. Areas of high scattering attenuation coincide with the volcanic edifice and the summit at which recent eruptions took place. The intrinsic dissipation pattern shows a strong contrast between the east and west side of the volcanic structure with the low values observed in the west interpreted as solidified magma bodies. Our results demonstrate a strong relationship between structural heterogeneities and attenuation processes in volcanic areas and confirm the effectiveness of the present technique, which can be used as an imaging tool complementary to conventional techniques.

  19. Tephra Fallout Hazard Assessment for VEI5 Plinian Eruption at Kuju Volcano, Japan, Using TEPHRA2

    NASA Astrophysics Data System (ADS)

    Tsuji, Tomohiro; Ikeda, Michiharu; Kishimoto, Hiroshi; Fujita, Koji; Nishizaka, Naoki; Onishi, Kozo

    2017-06-01

    Tephra fallout has a potential impact on engineered structures and systems at nuclear power plants. We provide the first report estimating potential accumulations of tephra fallout as big as VEI5 eruption from Kuju Volcano and calculated hazard curves at the Ikata Power Plant, using the TEPHRA2 computer program. We reconstructed the eruptive parameters of Kj-P1 tephra fallout deposit based on geological survey and literature review. A series of parameter studies were carried out to determine the best values of empirical parameters, such as diffusion coefficient and the fall time threshold. Based on such a reconstruction, we represent probabilistic analyses which assess the variation in meteorological condition, using wind profiles extracted from a 22 year long wind dataset. The obtained hazard curves and probability maps of tephra fallout associated to a Plinian eruption were used to discuss the exceeding probability at the site and the implications of such a severe eruption scenario.

  20. Sequence of the 1895 eruption of the Zao volcano, Tohoku Japan

    NASA Astrophysics Data System (ADS)

    Miura, Kotaro; Ban, Masao; Ohba, Tsukasa; Fujinawa, Akihiko

    2012-12-01

    The most recent major eruption event of the Zao volcano comprised a series of phreatic eruption episodes on 15 and 19 February, 22 August, and 27-28 September 1895, with several precursory vulcanian eruptions during February-July 1894. All were generated at the Okama crater lake located inside the Umanose caldera. The eruption products consist mainly of hydrothermally altered ash with altered blocks, except for ash from 1984. The eruption deposits of 1895 are divided lithologically into six layers (1-6). Comparison of the document with the lithofacies of deposits shows that layers 1, 2, 3-4, and 5-6 were correlated respectively with eruption episodes of 15 February (episode 1), 19 February (episode 2), 22 August (episode3), and 27-28 September (episode 4). During these four episodes, ca. 0.5%, 0.5%, 1.5%, and 98% of the total mass of the products had been discharged. Based on lithologic, stratigraphic, granulometric, and component analyses and on distributional features for these layers, the following depositional mechanisms were inferred. Layers 1, 3, and 4 were formed mainly from their related small pyroclastic density currents, whereas layer 2 resulted mainly from a small pyroclastic fall. In contrast, layers 5 and 6 are larger-scale near-vent pyroclastic fall deposits from ash clouds and eruption clouds, which might have included some juvenile fragments. The three early episodes in 1985 led to the climactic episode of 27-28 September. Furthermore, the andesitic magma chamber at < 3 kb depth, which caused the 1894 vulcanian eruptions, became a hydrothermal alteration source for the 1895 erupted materials. The chamber was re-activated before 1895 eruption by injection of basaltic magmas from greater depth. The injection reached maximum at the climactic event. The inferred course of that series of eruption episodes provides useful information to predict future volcanic phreatic-type eruptions at this volcano.

  1. Magma generation process beneath volcanic front of Kyushu arc, southwest Japan

    NASA Astrophysics Data System (ADS)

    Tamura, T.; Hasenaka, T.; Wallace, P. J.; Yasuda, A.; Mori, Y.

    2015-12-01

    We presents data for major and volatile (H2O, CO2, S, Cl) elements in olivine-hosted melt inclusions from Quaternary volcanoes (Aso, Kuju, Kirishima and Kaimon) along volcanic front of Kyushu arc, southwest Japan. Melt inclusion data are corrected for post-entrapment modifications including diffusive Fe-loss, H2O loss and post-entrapment crystallization. The primitive magma compositions calculated from corrected melt inclusion data are used to estimate the degree of partial melting and compositions of slab-derived fluids beneath Kyushu volcanic front. The result show that magmatism of four volcanoes in Kyushu arc is divided into two groups (Group A and B). Group A indicates high K2O contents in primitive magmas and in fluids at Aso and Kuju volcanoes, northern Kyushu arc. Group B indicates low K2O contents in primitive magmas and in fluids at Kirishima and Kaimon volcanoes, southern Kyushu arc. K2O contents of Group A and B are impossible of explaining by degree of partial melting and the origin of hydrous mantle. High K2O content in fluids is attributed to dehydration of phengite-bearing slab at deep depth (about 140 km) in Group A compared with shallow depth (about 100 km) in Group B. Phengite is dehydrated from submerging plate beneath 110 km depth. This study suggests that compositions of primitive magmas beneath Kyushu arc are reflected by the depth of slab and the kind of dehydrating hydrous minerals.

  2. Progressive enrichment of arc magmas caused by the subduction of seamounts under Nishinoshima volcano, Izu-Bonin Arc, Japan

    NASA Astrophysics Data System (ADS)

    Sano, Takashi; Shirao, Motomaro; Tani, Kenichiro; Tsutsumi, Yukiyasu; Kiyokawa, Shoichi; Fujii, Toshitsugu

    2016-06-01

    The chemical composition of intraplate seamounts is distinct from normal seafloor material, meaning that the subduction of seamounts at a convergent margin can cause a change in the chemistry of the mantle wedge and associated arc magmas. Nishinoshima, a volcanic island in the Izu-Bonin Arc of Japan, has been erupting continuously over the past 2 years, providing an ideal opportunity to examine the effect of seamount subduction on the chemistry of arc magmas. Our research is based on the whole-rock geochemistry and the chemistry of minerals within lavas and air-fall scoria from Nishinoshima that were erupted before 1702, in 1973-1974, and in 2014. The mineral phases within the analyzed samples crystallized under hydrous conditions (H2O = 3-4 wt.%) at temperatures of 970 °C-990 °C in a shallow (3-6 km depth) magma chamber. Trace element data indicate that the recently erupted Nishinoshima volcanics are much less depleted in the high field strength elements (Nb, Ta, Zr, Hf) than other volcanics within the Izu-Bonin Arc. In addition, the level of enrichment in the Nishinoshima magmas has increased in recent years, probably due to the addition of material from HIMU-enriched (i.e., high Nb/Zr and Ta/Hf) seamounts on the Pacific Plate, which is being subducted westwards beneath the Philippine Sea Plate. This suggests that the chemistry of scoria from Nishinoshima volcano records the progressive addition of components derived from subducted seamounts.

  3. CO2 emission from lake-filled Katanuma crater, Narugo volcano, Japan

    NASA Astrophysics Data System (ADS)

    Padron, E.; Hernandez Perez, P. A.; Mori, T.; Perez, N.

    2010-12-01

    Narugo volcano is composed by four dacitic Holocene age lava domes surrounding the 400 m wide lake-filled Katanuma crater. A large caldera, 5.5 x 7 km NW of the city of Sendai was formed by paroxysmal eruptions 45 ka ago and after this activity, lava flows and lava domes were formed in the inner part of the caldera. The only known eruption at Narugo in historical time occurred in 837 AD. Katanuma is known as one of the most acidic lakes in the world and boiling springs, water vapour and volcanic gases are discharged from the lake botton. As a result of this degassing, a relatively intense volcanic gas emission is observed along the lake surface in the form of gas bubbles. To compute the total CO2 degassing rate through Katanuma water lake surface, a CO2 emission survey was carried out on August 2010. CO2 efflux measurements were performed on the water surface by means of a portable NDIR sensor at 86 sampling sites, following a modified floating device of the accumulation chamber method.CO2 efflux values ranged between 16 and 14300 g m-2 d-1. CO2 efflux map was constructed using sequential Gaussian simulation. An important CO2 degassing structure was observed at the water surface, located on its west half part, with a N-S trending. An averaged map of 200 equiprobable simulations allowed us to compute 35.2 ± 4.1 t/d of CO2 released to the atmosphere through the water surface on a area of 0.14 km2. These results suggest clearly that monitoring CO2 emission rate from lake-filled Katanuma crater will contribute to improve the Narugo volcano surveillance program as well as our knowledge on the global CO2 emission from volcanic lakes, which is actually estimated about 136 Mt year-1 (Pérez et al., 2010). Reference: Pérez et al., 2010. CVL 7 Workshop Costa Rica, March 2010.

  4. Primary melt from Sannome-gata volcano, NE Japan arc: constraints on generation conditions of rear-arc magmas

    NASA Astrophysics Data System (ADS)

    Kuritani, T.; Yoshida, T.; Kimura, J.; Takahashi, T.; Hirahara, Y.; Miyazaki, T.; Senda, R.; Chang, Q.; Ito, Y.

    2013-12-01

    Material and energy transport in subduction zones has played an important role in Earth's evolution, and has been investigated extensively in petrological, geochemical, experimental, numerical, and geophysical studies. In these approaches, petrological and geochemical studies on arc basalts have remarkably contributed to the quantitative understanding of subduction-zone processes. However, a more rigorous understanding is limited by the fact that primary magmas generated in the mantle erupt only very occasionally without significant thermal and mechanical interaction with the crust. In this study, the conditions under which arc magma is generated are estimated using primary basalts from the Sannome-gata volcano, located in the rear of the NE Japan arc. The NE Japan arc has been investigated extensively, and is one of the best-documented volcanic arcs on Earth. Therefore, the reliable estimates of the magma generation conditions are expected to contribute to gaining a better understanding of subduction-zone processes. The Sannome-gata maar is located in the Oga Peninsula, NE Japan. The age of the volcanic activity is 20-24 ka (Kitamura 1990). We have examined the petrology and geochemistry of basaltic scoria samples that were collected from scoria fall deposits, outcropping around 500 m southwest of the Sannome-gata maar (Yoshinaga and Nakagawa 1999). The scoriae occur with abundant mantle and crustal xenoliths, suggesting that the magma ascended rapidly from the upper mantle. They show significant variations in their whole-rock compositions (7.9-11.1 wt.% in MgO). High-MgO scoriae (MgO > ~9.5 wt.%) have mostly homogeneous 87Sr/86Sr ratios (~0.70318), whereas low-MgO scoriae (MgO <~9 wt.%) have higher 87Sr/86Sr ratios (>0.70327); ratios tend to increase with decreasing MgO content. The high-MgO scoriae are aphyric, containing ~5 vol.% olivine microphenocrysts with Mg# of up to 90. In contrast, the low-MgO scoriae have crustal xenocrysts of plagioclase, alkali

  5. Long-term thermal activity revealed by magnetic measurements at Kusatsu-Shirane volcano, Japan

    NASA Astrophysics Data System (ADS)

    Takahashi, Kosuke; Fujii, Ikuko

    2014-09-01

    Repeated geomagnetic measurements commenced around the three summit crater lakes of Kusatsu-Shirane volcano (Yugama, Mizugama and Karegama lakes) in 1976 and continuous measurements commenced in 1990. We reviewed and analyzed these geomagnetic data acquired over the 34 years starting in 1978. Changes in the geomagnetic field related to eruptions during 1982-1983 were recorded in the repeated geomagnetic measurements from 1982 to 1985. A thermal-demagnetization source was estimated to be 400 m below Mizugama crater lake during this period. Although there were no eruptions from 1988 to 1991, there were numerous volcanic earthquakes. Thermomagnetic signals due to demagnetization of the material beneath the crater lakes were recorded by the repeated magnetic measurements during this period. The demagnetized body was estimated to be 600 m below Mizugama crater lake at this time. Previous seismological and geochemical studies attributed these demagnetization events to the ascent of hydrothermal water and volcanic gas. The difference between the depths of demagnetized bodies during these two periods of demagnetization may provide important information about the mechanism of the 1982-1983 eruptions. In contrast, magnetization associated with cooling of rocks beneath the crater lakes was recorded from 1996 to 2012. According to our thermomagnetic modeling of this period, the source of the magnetization was 400 to 700 m below an area immediately northeast of Yugama crater lake and the cooling migrated gradually to shallower depths during this period. Based on our modeling, seismological data, and geochemical monitoring of Yugama lake water, we consider that the flux of hydrothermal fluid from depth decreased after 1992 and rock magnetization due to cooling began in 1996.

  6. Recent uplift of Iwo-yama volcano, Kirishima Volcanic Complex, southwest Japan, derived from ALOS-2 images

    NASA Astrophysics Data System (ADS)

    Arai, H.; Aoki, Y.

    2016-12-01

    Phreatic eruptions are usually smaller than magmatic eruptions, but they are sometimes a source of major hazards if infrastructures are close by. Here we report on rapid ground uplift in Iwo-yama volcano, one of vents in Kirishima Volcanic Complex, southwest Japan, potentiallly leading to a phreatic eruption.Kirishima Volcanic Complex is a collection of volcanic vents striking northwest-southeast. Shinmoe-dake, one of the vents in the volcanic complex, had sub-Plinian and Vulcanian eruptions in early 2011. Iwo-yama is located about 6 km to the northwest of Shinmoe-dake. In Iwo-yama, elevated surface temperature has been observed since December 2015 and volcanic earthquakes and tremors have been observed in January and February 2016. With this background, we investigated the temporal evolution of the deformation in Iwo-yama volcano inferred from Synthetic Aperture Radar images taken from the ALOS-2 satellite.We first generated interferograms all possible pairs of SAR images. Then we applied a time-series analysis to extract the temporal evolution of deformation of volcanic origin by removing errors due to the uncertainty of Digital Elevation Model and atmospheric disturbance. The time-series analysis reveals an uplift of a region with a diameter of about 500 meters. We found that the uplift started in late 2015 and amounts up to approximately 60 mm as of June 2016. The deformation pattern looks like almost a mirror of the subsidence observed in 1990s by JERS-1 images. These observations by JERS-1 and ALOS-2 suggest a depressurization in 1990s and a recent pressurization of the same aquifer located a few hundred meters beneath the surface. Electromagnetic observations also endorse the existence of the shallow acquire at the same depth level as we suggest. We need to note that the recent uplift continues even after a cessation of the volcanic earthquakes and tremors in late February 2016. This indicates that the observation of ground deformation adds insights into the

  7. Recent uplift of Iwo-yama volcano, Kirishima Volcanic Complex, southwest Japan, derived from ALOS-2 images

    NASA Astrophysics Data System (ADS)

    Aoki, Yosuke; Arai, Hiroki

    2017-04-01

    Phreatic eruptions are usually smaller than magmatic eruptions, but they are sometimes a source of major hazards if infrastructures are close by. Here we report on rapid ground uplift in Iwo-yama volcano, one of vents in Kirishima Volcanic Complex, southwest Japan, potentiallly leading to a phreatic eruption. Kirishima Volcanic Complex is a collection of volcanic vents striking northwest-southeast. Shinmoe-dake, one of the vents in the volcanic complex, had sub-Plinian and Vulcanian eruptions in early 2011. Iwo-yama is located about 6 km to the northwest of Shinmoe-dake. In Iwo-yama, elevated surface temperature has been observed since December 2015 and volcanic earthquakes and tremors have been observed in January and February 2016. With this background, we investigated the temporal evolution of the deformation in Iwo-yama volcano inferred from Synthetic Aperture Radar images taken from the ALOS-2 satellite. We first generated interferograms all possible pairs of SAR images. Then we applied a time-series analysis to extract the temporal evolution of deformation of volcanic origin by removing errors due to the uncertainty of Digital Elevation Model and atmospheric disturbance. The time-series analysis reveals an uplift of a region with a diameter of about 500 meters. We found that the uplift started in late 2015 and amounts up to approximately 60 mm as of June 2016. The deformation pattern looks like almost a mirror of the subsidence observed in 1990s by JERS-1 images. These observations by JERS-1 and ALOS-2 suggest a deflation in 1990s and recent inflation of an aquifer located a few hundred meters beneath the summit. Electromagnetic observations also endorse the existence of the shallow acquifer that we suggest is responsible for the observed deformation. We need to note that the recent uplift continues even after a cessation of the volcanic earthquakes and tremors in late February 2016. This indicates that the observation of ground deformation adds insights into

  8. Petrological characteristics and volatile content of magma from the 2000 eruption of Miyakejima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Saito, Genji; Uto, Kozo; Kazahaya, Kohei; Shinohara, Hiroshi; Kawanabe, Yoshihisa; Satoh, Hisao

    2005-03-01

    Among the series of eruptions at Miyakejima volcano in 2000, the largest summit explosion occurred on 18 August 2000. During this explosion, vesiculated bombs and lapilli having cauliflower-like shapes were ejected as essential products. Petrological observation and chemical analyses of the essential ejecta and melt inclusions were carried out in order to investigate magma ascent and eruption processes. SEM images indicate that the essential bombs and lapilli have similar textures, which have many tiny bubbles, crystal-rich and glass-poor groundmass and microphenocrysts of plagioclase, augite and olivine. Black ash particles, which compose 40% of the air-fall ash from the explosion, also have similar textures to the essential bombs. Whole-rock analyses show that the chemical composition of all essential ejecta is basaltic (SiO2=51 52 wt%). Chemical analyses of melt inclusions in plagioclase and olivine phenocrysts indicate that melt in the magma had 0.9 1.9 wt% H2O, <0.011 wt% CO2, 0.04 0.17 wt% S and 0.06 0.1 wt% Cl. The variation in volatile content suggests degassing of the magma during ascent up to a depth of about 1 km. The ratio of H2O and S content of melt inclusions is similar to that of volcanic gas, which has been intensely and continuously emitted from the summit since the end of August 2000, indicating that the 18 August magma is the source of the gas emission. Based on the volatile content of the melt inclusions and the volcanic gas composition, the initial bulk volatile content of the magma was estimated to be 1.6 1.9 wt% H2O, 0.08 0.1 wt% CO2, 0.11 0.17 wt% S and 0.06 0.07 wt% Cl. The basaltic magma ascended from a deeper chamber (˜10 km) due to decrease in magma density caused by volatile exsolution with pressure decrease. The highly vesiculated magma, which had at least 30 vol% bubbles, may have come into contact with ground water at sea level causing the large explosion of 18 August 2000.

  9. Petrological studies of volcanic ash from Sakurajima volcano in 2013, Southern Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Andri Kurniawan, Idham; Sakakibara, Masayuki; Suparka, Emmy

    2017-06-01

    Many petrological studies of volcanic rocks have attempted to better predict future volcanic activity. In this study, we examined volcanic ash samples from Showa Crater in Sakurajima, Japan, which were erupted from January to October 2013. This study was used two types of juvenile material; black vesicular volcanic rock (BVVR) and black non-vesicular volcanic rock (BNVVR) to determine the variable of magmatic processes in the magma conduit during the 2013 eruption. We divided the duration into three periods such as January to April, April to July, and July to October based on the variable tendency of SiO2 contents and volume abundance of the interstitial glasses in BVVR and BNVVR. The estimated melt compositions demonstrate that the variability of SiO2 contents and volume abundance of microcrystal in the groundmass (BVVR and BNVVR) over time were caused by micro-crystallization processes. The estimated of water contents and vesicle volume shows the influence of degassing process in the rock forming. Also, the correlation of petrological features with the number of eruptions and eruptive volumes, exhibit the variable of magma supply into conduit in each period. Consequently, careful monitoring of the petrological features of erupted materials may provide useful constraints on future eruptive activity and thereby assist in the mitigation of volcanic hazards.

  10. Horizontal and low-angle cross-stratifications from volcaniclastic sedimentary sequences: Outburst flood deposits, Numazawa and Ontake volcanoes, Japan

    NASA Astrophysics Data System (ADS)

    Kataoka, Kyoko

    2017-04-01

    This talk focuses on the formation and preservation of sedimentary structures such as horizontal and low-angle cross-stratifications in volcaniclastic sedimentary (lahar) sequences. The 5 ka outburst flood deposits in the Tadami river catchment, Numazawa volcano, Japan is presented as a first example. The flood, with a peak discharge of > 37,000-58,000 m^3/s from ignimbrite-dammed valley left pumiceous gravelly sediments with meter-sized boulders in the flow path (Kataoka et al., 2008). Up to 30 m thick sequence attributed to the flood formed a low gradient fan of 10 km long and 1.5-3 km wide, covering an area of 18 km2 with a total volume of > 0.5 km3 at the downstream end of the Tadami River. Outcrop observations accompanied with extensive surveys of Ground Penetrating Radar (GPR) along 200 to 500 m lateral and longitudinal transects over the flood fan revealed bedforms of the deposits. The profiles show large internal cross structures with 2-5 m amplitude and 10s m wavelength indicating lateral/downstream accretion in flood fan deposits. Some of them are slightly inclined towards upstream (backsets) which may suggest upstream migration of bedforms. These cross stratifications in the GPR profiles correspond to low-angle cross-stratifications or horizontal stratifications observed in outcrops. In outcrops, the stratified flood deposits mainly comprises rounded pumice pebble and cobble gravel and sand sized mineral grains. Bedding structures include horizontal stratifications and low-angle, low-amplitude, long wavelength cross-stratifications that occasionally climb. Individual 5 cm to decimeters-thick bed sets are commonly inversely graded. The deposits imply 1) high sediment concentration within a flow and 2) aggradation and bedform migration occurred in relation with traction carpet sedimentation. Especially thick traction carpets were probably formed because of 1) high stream power to drive near bed layer deeper and 2) a density contrast among volcaniclastic

  11. Fluidized landslides induced by extreme rainfall along basaltic caldera cliff of Mt. Aso in July 2012

    NASA Astrophysics Data System (ADS)

    Fukuoka, Hiroshi; Matsushi, Yuki; Furuya, Gen; Saito, Hitoshi

    2013-04-01

    In the end of the rainy season of 2012, a extreme rainfall affected western Japan in July and induced hundreds of fluidized landslides claiming casualties of more than 20. Measured trigger precipitation was recorded by the nearby ground-based station of the AMeDAS network (Automated Meteorological Data Acquisition System)as about 80 mm/h for consecutive 4 hours. Analysis of Radar-Raingauge Analyzed Precipitation-operated by the Japan Meteorological Agency showed landslide affected area almost coincided with the ones of heavier precipitation. Most of the landslides took place along the outer caldera rim and flank of the central cone of Mt. Aso, a basaltic active volcano. Most of the landslides slid on the boundary of strongly weathered soils, which used to be new volcanic accretion materials. Outstanding features of these landslides are: (1) This area had been affected by similar heavy rainfall decades ago, however, again a number of landslides took place in the nearby past scars; (2) Many of the soil slide bodies are shallow less than 5 meters deep and possibly immediately transformed into debris flows or mud flows and traveled long distance to reach the downslope communities; (3) Visual observation of the sources showed the high possibility that some of the slides were apparently induced by liquefaction. Similar cases were reported of past 2 landslide disasters in Japan. This strongly suggests that excessive rainfall can trigger numerous mud flows of unexpected reach. We conducted close field study at a typical soil slide - mud flow site. It originally initiated as debris or soil slide on a thin steep bedding plane of about 34 degrees consisting of coarser accretion materials. Needle penetration test showed comparatively weaker strength in the layer. It is underlain by a layer of finer materials. Such a higher permeability contrast could contribute to higher susceptibility of excess pore pressure generation. We took soil samples from the vicinity of sliding

  12. Estimation of total discharged mass from the phreatic eruption of Ontake Volcano, central Japan, on September 27, 2014

    NASA Astrophysics Data System (ADS)

    Takarada, Shinji; Oikawa, Teruki; Furukawa, Ryuta; Hoshizumi, Hideo; Itoh, Jun'ichi; Geshi, Nobuo; Miyagi, Isoji

    2016-08-01

    The total mass discharged by the phreatic eruption of Ontake Volcano, central Japan, on September 27, 2014, was estimated using several methods. The estimated discharged mass was 1.2 × 106 t (segment integration method), 8.9 × 105 t (Pyle's exponential method), and varied from 8.6 × 103 to 2.5 × 106 t (Hayakawa's single isopach method). The segment integration and Pyle's exponential methods gave similar values. The single isopach method, however, gave a wide range of results depending on which contour was used. Therefore, the total discharged mass of the 2014 eruption is estimated at between 8.9 × 105 and 1.2 × 106 t. More than 90 % of the total mass accumulated within the proximal area. This shows how important it is to include a proximal area field survey for the total mass estimation of phreatic eruptions. A detailed isopleth mass distribution map was prepared covering as far as 85 km from the source. The main ash-fall dispersal was ENE in the proximal and medial areas and E in the distal area. The secondary distribution lobes also extended to the S and NW proximally, reflecting the effects of elutriation ash and surge deposits from pyroclastic density currents during the phreatic eruption. The total discharged mass of the 1979 phreatic eruption was also calculated for comparison. The resulting volume of 1.9 × 106 t (using the segment integration method) indicates that it was about 1.6-2.1 times larger than the 2014 eruption. The estimated average discharged mass flux rate of the 2014 eruption was 1.7 × 108 kg/h and for the 1979 eruption was 1.0 × 108 kg/h. One of the possible reasons for the higher flux rate of the 2014 eruption is the occurrence of pyroclastic density currents at the summit area.

  13. Relationship between eruptive style and vesicularity of juvenile clasts during eruptive episode A of Towada Volcano, Northeast Japan

    NASA Astrophysics Data System (ADS)

    Hiroi, Yoshimi; Miyamoto, Tsuyoshi

    2016-10-01

    It has been reported that juvenile pumice lapilli found in plinian eruptions have high vesicularity, while those found in phreatoplinian eruptions have low vesicularity. However, juvenile glass shards from phreatoplinian eruptions consist of large, expanded bubbles such as bubble wall-type glass. These glass shards seem to possess high vesicularity, unlike the pumice lapilli. This study examines the factors causing this difference, especially focusing on the temporal variations in the vesicularity of the juvenile pyroclasts from eruptive episode A of Towada Volcano, Northeast Japan. This examination was conducted through four analyses: density measurements of pumice lapilli, thin section texture classification of pumice lapilli, classification of glass shards, and surface texture classification of pumice lapilli. Further, pumice lapilli from plinian eruptions have a low density, and those from phreatoplinian eruptions are characterized by high density. The density of the pumice lapilli depends on the eruption style and is hence determined after the eruption. A progressive increase in the amount of large bubbles is observed in glass shards ejected during an eruptive magmatic to phreatomagmatic sequence. Because it does not hinge on the eruptive style, it is assumed that the vesicularity of the glass shards is kept from the conduit before contact with water, especially on fragmentation by magma vesiculation in the conduit. The surfaces of the pumice lapilli show a similar increase in vesicularity with time as glass shards. However, this increase is not successive throughout, but decreases temporarily at the phreatomagmatic stage of the eruption, as in the case of density. This indicates that the successive bubble growth continues within the pumice, and additional vesiculation is superposed when the magmatic eruption comes into contact with water. Because of this, different juvenile clasts exhibit different vesicularities upon cooling. Interestingly, magma

  14. A multi-parametric approach to studying volcanic lightning utilizing LMA observations, ash characteristics, plume dynamics, seismic, and infrasound data at Sakurajima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Smith, C. M.; Van Eaton, A. R.; McNutt, S. R.; Behnke, S. A.; Cimarelli, C.; Thomas, R. J.; Edens, H. E.; Cigala, V.

    2016-12-01

    The May-June 2015 eruptive period of Sakurajima Volcano, located in southern Kyushu Province, Japan was studied using 9 Lightning Mapping Array (LMA) units, 2 broadband seismometers, 6 infrasound sensors, and video footage of the plume (infrared and lowlight). Studies were performed in cooperation with the Sakurajima Volcano Observatory. In addition, several dozen temporal ash samples were taken during multiple eruptive episodes. Volcanic lightning, especially small vent discharges, was prevalent during this eruptive period. Previous work at Sakurajima has shown relationships between overall plume charge and ash grain size as well as mineral number density and maximum seismic amplitude. We take a multi-parametric approach and examine a full suite of ash grain characteristics (including grain size distributions, particle shapes, componentry, and microlite number densities), plume heights and eruption durations, seismic and infrasound amplitudes, and the occurrence of volcanic lighting. We seek to determine the underlying relationships between commonly measured parameters and the production of volcanic lighting.

  15. Frictional control on eruptive style at Mt. Unzen (Japan) and Santiaguito volcano (Guatemala)

    NASA Astrophysics Data System (ADS)

    Hornby, A. J.; Kendrick, J. E.; Hirose, T.; De Angelis, S.; Henton De Angelis, S.; Lavallee, Y.; Umakoshi, K.

    2013-12-01

    velocities led to increased melt productivity with a diminishing control on shear resistance at the slip zone. These relationships suggest a non-Newtonian rheology for frictional melt, which induces slip dynamics that do not abide to Byerlee's rule. We note that while the total slip required to undergo frictional melting diminishes with axial stress and slip velocity, Santiaguito dome samples required greater distances to achieve melting than Unzen samples (at the same conditions). Dome material from Santiaguito and Unzen show a remarkably similar mechanical response upon frictional melting. At shallow depths frictional melting may exert a viscous brake on slip, encouraging stick-slip behaviour at dome volcanoes. This study concludes that frictional melting changes the mechanical properties of rocks at a fault surface, and thus the rheology driving dome extrusion may not be derived directly from the relict dome material itself.

  16. Long-term geochemical surveillance of fumaroles at Showa-Shinzan dome, Usu volcano, Japan

    USGS Publications Warehouse

    Symonds, R.B.; Mizutani, Y.; Briggs, P.H.

    1996-01-01

    This study investigates 31 years of fumarole gas and condensate (trace elements) data from Showa-Shinzan, a dacitic dome-cryptodome complex that formed during the 1943-1945 eruption of Usu volcano. Forty-two gas samples were collected from the highest-temperature fumarole, named A-1, from 1954 (800??C) to 1985 (336??C), and from lower-temperature vents. Condensates were collected contemporaneously with the gas samples, and we reanalyzed ten of these samples, mostly from the A-1 vent, for 32 cations and three anions. Modeling using the thermochemical equilibrium program, SOLVGAS, shows that the gas samples are mild disequilibrium mixtures because they: (a) contain unequilibrated sedimentary CH4 and NH3; (b) have unequilibrated meteoric water; or (c) lost CO, either by air oxidation or by absorption by the sodium hydroxide sampling solution. SOLVGAS also enabled us to restore the samples by removing these disequilibrium effects, and to estimate their equilibrium oxygen fugacities and amounts of S2 and CH4. The restored compositions contain > 98% H2O with minor to trace amounts of CO2, H2, HCl, SO2, HF, H2S, CO, S2 and CH4. We used the restored gas and condensate data to test the hypotheses that these time-series compositional data from the dome's fumaroles provide: (1) sufficient major-gas data to analyze long-term degassing trends of the dome's magma-hydrothermal system without the influence of sampling or contamination effects; (2) independent oxygen fugacity-versus-temperature estimates of the Showa-Shinzan dacite; (3) the order of release of trace elements, especially metals, from magma; and (4) useful information for assessing volcanic hazards. The 1954-1985 restored A-1 gas compositions confirm the first hypothesis because they are sufficient to reveal three long-term degassing trends: (1) they became increasingly H2O-rich with time due to the progressive influx of meteoric water into the dome; (2) their C/S and S/Cl ratios decreased dramatically while their Cl

  17. Chronology and products of the 2000 eruption of Miyakejima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Nakada, S.; Nagai, M.; Kaneko, T.; Nozawa, A.; Suzuki-Kamata, K.

    2005-03-01

    Lateral migration of magma away from Miyakejima volcanic island, Japan, generated summit subsidence, associated with summit explosions in the summer of 2000. An earthquake swarm beneath Miyakejima began on the evening of 26 June 2000, followed by a submarine eruption the next morning. Strong seismic activity continued under the sea from beneath the coast of Miyakejima to a few tens of kilometers northwest of the island. Summit eruptive event began with subsidence of the summit on 8 July and both explosions and subsidence continued intermittently through July and August. The most intense eruptive event occurred on 18 August and was vulcanian to subplinian in type. Ash lofted into the stratosphere fell over the entire island, and abundant volcanic bombs were erupted at this time. Another large explosion took place on 29 August. This generated a low-temperature pyroclastic surge, which covered a residential area on the northern coast of the island. The total volume of tephra erupted was 9.3×106 m3 (DRE), much smaller than the volume of the resulting caldera (6×108 m3). Migration of magma away from Miyakejima was associated with crustal extension northwest of Miyakejima and coincident shrinkage of Miyakejima Island itself during July August 2000. This magma migration probably caused stoping of roof rock into the magma reservoir, generating subsurface cavities filled with hydrothermal fluid and/or magmatic foam and formation of a caldera (Oyama Caldera) at the summit. Interaction of hydrothermal fluid with ascending magma drove a series of phreatic to phreatomagmatic eruptions. It is likely that new magma was supplied to the reservoir from the bottom during waning stage of magma’s migration, resulting in explosive discharge on 18 August. The 18 August event and phreatic explosions on 29 August produced a conduit system that allowed abundant SO2 emission (as high as 460 kg s-1) after the major eruptive events were over. At the time of writing, inhabitants of the

  18. Japan.

    ERIC Educational Resources Information Center

    Geiger, Rita; And Others

    The document offers practical and motivating techniques for studying Japan. Dedicated to promoting global awareness, separate sections discuss Japan's geography, history, culture, education, government, economics, energy, transportation, and communication. Each section presents a topical overview; suggested classroom activities; and easily…

  19. Japan.

    ERIC Educational Resources Information Center

    Geiger, Rita; And Others

    The document offers practical and motivating techniques for studying Japan. Dedicated to promoting global awareness, separate sections discuss Japan's geography, history, culture, education, government, economics, energy, transportation, and communication. Each section presents a topical overview; suggested classroom activities; and easily…

  20. The effect of shear on permeability in a volcanic conduit: a case study at Unzen volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ashworth, James; Lavallée, Yan; Wallace, Paul; Lamur, Anthony; Kendrick, Jackie; Miwa, Takahiro

    2016-04-01

    The efficiency of outgassing at volcanoes is a function of permeability, and exerts a major influence on the type of eruptive behaviour exhibited. Understanding how shear affects the permeability profile across volcanic conduits is therefore a key part of understanding volcanic processes and the associated hazards. During the final months of the 1990-1995 eruption of Unzen volcano in southern Japan, extrusion of a dacite spine followed a period of endogenous dome growth. Many of the resulting formations are relatively accessible, allowing for the study of a variety of associated deformation phenomena. One of these formations, a ~6 m wide block, is a section of the extruded spine, that forms the basis for this study on shallow conduit processes. It displays a textural gradation from highly sheared rock to rock with negligible deformation, and is bounded at the high shear end by an agglutinated block of gouge that is thought to represent the conduit margin. A multi-faceted approach was taken to investigate the variation of permeability across the spine and its implications for processes occurring within the conduit. The permeability was measured at several points along the exposed surface of the spine transect using a field permeameter. Sample blocks from four of these locations were collected and tested in the lab using a hydrostatic pressure vessel water-flow permeameter and categorized as: gouge; highest shear; moderate shear; negligible shear. Each block was tested in three orthogonal axes: one perpendicular to observed shear; and two in the plane of shear. For each of these rocks, permeability and porosity measurements were made at a wide range of effective pressures (5 to 100 MPa), using a controlled upstream/downstream pore pressure gradient of 0.5 MPa (at an average pore pressure of 1.25 MPa). Thin sections of each sample were also taken prepared and analysed to describe the primary microstructures controlling the permeability of the rock. Textural analysis

  1. Petrogenesis of mafic magma and associated silicic magma for calk-alkaline rocks in the Shirataka volcano, NE Japan

    NASA Astrophysics Data System (ADS)

    Hirotani, S.; Ban, M.; Nakagawa, M.

    2009-12-01

    Eruptive products of Shirataka volcano (0.9-0.7 Ma) in NE Japan are calc-alkaline andesite-dacite (57-66% SiO2), and are divided into six petrologic groups (G1-6). Mafic inclusions (48-58% SiO2) are always observed in G1, G2, G5 and G6. The host rocks as well as inclusions are mixed rocks formed between mafic and silicic end-members judging from many petrologic aspects. Based on petrologic data of more than 30 mafic inclusion-host pairs in these groups, we revealed the petrologic features of the end-member magmas and examined their petrogenesis. The mixing trends defined by hosts and inclusions are divided into high- and low-Cr types. Both types coexist in G1, G2 and G5, while G6 lacks high-Cr type. In the same group, the mafic end-member for high-Cr type shows more primitive features (e.g. in G5; 1140-1160°C, 50% SiO2, Fo-rich olv + Mg-rich cpx + An-rich plg phenocrysts) than that for the low-Cr type (e.g. in G5; c. 1100°C, 51% SiO2, Mg-rich cpx + An-rich plg phenocrysts). The silicic end-members for the two types show similar mineral assemblage (e.g. in G5; hbl + qtz + Mg-poor px + An-poor plg phenocrysts) but are different in bulk compositions (e.g. in G5; high-Cr type, 67% SiO2; low-Cr type, 66% SiO2). Significantly, in a petrologic group, the high-Cr type mafic and corresponding silicic end-members have lower values in 87Sr/86Sr ratio than the low-Cr type ones. Further, the bulk compositions of each type end-members show slight variability among petrologic groups. For example, Sr isotopic ratios and SiO2 contents of high-Cr type mafic end-members are 0.7037 and 48% in G1, 0.7039 and 51% in G2, and 0.7042 and 50% in G5, respectively. The MELTS and geochemical model calculations have shown that the low-Cr type mafic end-member magma can be produced through c. 20% fractional crystallization (olv + plg) from the high-Cr type mafic end-member magma accompanied with the assimilation of basement plutonic rocks (r=0.02-0.05) in the case of G5. In terms of associated

  2. Development of low noise cosmic ray muon detector for imaging density structure of Usu Volcano, Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Kusagaya, T.; Tanaka, H.; Taketa, A.; Oshima, H.; Maekawa, T.

    2012-12-01

    We are developing low noise cosmic ray muon detector to image a density structure of Usu Volcano, Hokkaido, Japan by muon radiography. Intensity of cosmic ray muon penetrating through the object is expressed as a function of the product of muon path length and density along muon path. And, the intensity of penetrating muon steeply decreases if muon path length becomes longer or density along muon path becomes larger. The detector that we are developing is called hodoscope that consists of multiple Position Sensitive Detectors (PSDs). A PSD has NxM grids consisting of N vertically aligned Scintillation Counters (SC: a plastic scintillator attached to a photo multiplier tube) and M horizontally aligned SCs. We can identify a muon path direction with two or more PSDs by connecting muon-detecting points in each PSD. But, Usu Volcano is so large that the intensity of penetrating muon becomes lower, and then noise rate becomes higher: the count of penetrating cosmic ray muon is estimated to be a few counts per month with the detector of which has the cross-section area of one square meter and the solid angle of 0.01 steradian. The noise is defined as a particle other than the muon penetrating the observed object such as electrons, photons, vertically arriving muons and so on. If noise rate becomes higher, the measured intensity of penetrating muon becomes higher than the theoretical intensity of that. Then we get a wrong result as if there were matter of lower density relative to real. So we need to develop a low noise detector. The ElectroMagnetic (EM) shower that consists of many electrons and photons is thought to be one of noise. When EM shower reaches the detector, each PSD detects arriving particles and detecting points are sometimes connected by a straight line. In that case, we cannot discriminate the penetrating muon from EM shower, and we count it as a muon event. This results noise. In order to discriminate the noise event, the use of more PSDs for our

  3. Japan.

    PubMed

    1989-02-01

    Japan consists of 3900 islands and lies off the east coast of Asia. Even though Japan is one of the most densely populated nations in the world, its growth rate has stabilized at .5%. 94% of all children go to senior high school and almost 90% finish. Responsibility for the sick, aged, and infirmed is changing from the family and private sector to government. Japan was founded in 600 BC and its 1st capital was in Nara (710-1867). The Portuguese, the 1st Westerners to make contact with Japan in 1542, opened trade which lasted until the mid 17th century. US Navy Commodore Matthew Perry forced Japan to reopen in 1854. Following wars with China and Russia in the late 1800s and early 1900s respectively, Japan took part in World Wars I and II. In between these wars Japan invaded Manchuria and China. The US dropped an atomic bomb on Hiroshima and Nagasaki and the Japanese surrendered in September, 1945 ending World War II (WWII). Following, WWII, the Allied Powers guided Japan's establishment as a nonthreatening nation and a democratic parliamentary government (a constitutional monarchy) with a limited defense force. Japan remains one of the most politically stable of all postwar democracies. The Liberal Democratic Party's Noboru Takeshita became prime minister in 1987. Japan has limited natural resources and only 19% of the land is arable. Japanese ingenuity and skill combine to produce one of the highest per hectare crop yields in the world. Japan is a major economic power, and its and the US economies are becoming more interdependent. Its exports, making up only 13% of the gross national product, mainly go to Canada and the US. Many in the US are concerned, however, with the trade deficit with Japan and are seeking ways to make trade more equitable. Japan wishes to maintain good relations with its Asian neighbors and other nations. The US and Japan enjoy a strong, productive relationship.

  4. Growth History Of Unzen Volcano, Kyushu, Japan _| Results of Two Flank Drillings of Unzen Scientific Drilling Project

    NASA Astrophysics Data System (ADS)

    Hoshizumi, H.; Uto, K.; Matsumoto, A.; Kurihara, A.

    2004-12-01

    Unzen volcano is an active volcano composed of lava domes, thick lava flows and pyroclastic deposits of hornblende andesite to dacite. Tectonically active Unzen graben dissects volcanic edifices of the volcano. During the phase I of the Unzen Scientific Drilling Project (USDP), two drillings were conducted at the northeastern (USDP-1: 752 m depth) and eastern (USDP-2: 1463 m depth) flanks of the volcano, respectively, to fully recover accumulated deposits of the volcano hidden beneath the younger eruptives. Extensive K-Ar and 40Ar/39Ar age determinations have also been conducted on both surface rocks and drilling cores. Unzen volcano starts to grow at 0.5 Ma above the Pre-Unzen pyroxene andesite (0.5-0.8 Ma). Unzen volcano has been divided into three volcanic stages, Early and Late stages of the Older Unzen and the Younger Unzen. The Early stage of the Older Unzen (0.3-0.5 Ma) products consist of pumice-rich pyroclastic flows, block and ash flows, associated volcaniclastic debris flows and thick lava flows. The north- and south-dipping fans spreading outside the graben are sharply cut by the faults. This suggests that Unzen volcano grew rapidly in the first 200,000 years of its history and formed a conical volcanic edifice. The Late stage of the Older Unzen (0.15-0.3 Ma) products mainly fill in the graben. In the western half of the deposits of this stage, thick lava flows cover widely inside the Unzen graben. On the other hand, thick alternated piles of pyroclastic deposits were recovered both from USDP-1 and -2 cores. In the USDP-2 core, phreatomagmatic deposits about 250 m thick with essentially abundant glass materials of ca. 0.3 Ma. These findings suggest that rapid subsidence of the Unzen graben at around 0.3-0.2 Ma led strong interaction between the magma and groundwater. Younger Unzen volcano (0-0.15Ma) is composed of four edifices, Nodake, Myokendake, Fugen-dake and Mayuyama volcanoes, all locate in the eastern half of Unzen volcano. Block-and-ash flow

  5. Japan.

    PubMed

    1987-02-01

    Japan is composed of 4 main islands and more than 3900 smaller islands and has 317.7 persons/square kilometer. This makes it one of the most densely populated nations in the world. Religion is an important force in the life of the Japanese and most consider themselves Buddhists. Schooling is free through junior high but 90% of Japanese students complete high school. In fact, Japan enjoys one of the highest literacy rates in the world. There are over 178 newspapers and 3500 magazines published in Japan and the number of new book titles issued each year is greater than that in the US. Since WW1, Japan expanded its influence in Asia and its holdings in the Pacific. However, as a direct result of WW2, Japan lost all of its overseas possessions and was able to retain only its own islands. Since 1952, Japan has been ruled by conservative governments which cooperate closely with the West. Great economic growth has come since the post-treaty period. Japan as a constitutional monarchy operates within the framework of a constitution which became effective in May 1947. Executive power is vested in a cabinet which includes the prime minister and the ministers of state. Japan is one of the most politically stable of the postwar democracies and the Liberal Democratic Party is representative of Japanese moderate conservatism. The economy of Japan is strong and growing. With few resources, there is only 19% of Japanese land suitable for cultivation. Its exports earn only about 19% of the country's gross national product. More than 59 million workers comprise Japan's labor force, 40% of whom are women. Japan and the US are strongly linked trading partners and after Canada, Japan is the largest trading partner of the US. Foreign policy since 1952 has fostered close cooperation with the West and Japan is vitally interested in good relations with its neighbors. Relations with the Soviet Union are not close although Japan is attempting to improve the situation. US policy is based on

  6. Frequent but hidden eruptions of Adatara and Bandai volcanoes during the last 50,000 years unraveled by volcanic damlake sediments, northeast Japan

    NASA Astrophysics Data System (ADS)

    Kataoka, Kyoko; Nagahashi, Yoshitaka

    2017-04-01

    Adatara and Bandai volcanoes in the northeast Japan are very close to each other ( 18 km). Bandai volcano is well known for a large-scale debris avalanche following the phreatic eruption in AD1888 that took more than 400 fatalities. Eruptive history consists of at least 6 more debris avalanche events, 3 more phreatic eruptions, 6 lava flows, and 4 Vulcanian/sub-Plinian eruptions during the last 50,000 years revealed by subaerial proximal deposits. Whereas, the eruptive history of Adatara volcano comprises 6 Vulcanian and 5 phreatic eruptions during the last 10,000 years. The most recent eruption occurred in AD1899-1900. The studied sedimentary core (INW2012) was drilled out from Lake Inawashiro-ko, the largest dammed lake in Japan, that was formed by the 50 ka Okinajima debris avalanche event at Bandai volcano. The lake is 94 m deep, and drilling site is located at the central part of the lake ( 90 m deep). In the 28 m long core sequence, in contrast to background lake sediments deposited under a deep offshore environment, very frequent (70) intercalations of event layers are recognized. Eight types of event layers can be recognized: 1) gray muddy layer (Gm), 2) gray sandy layer (Gs), 3) brown muddy layer (Bm), 4) brown sandy layer (Bs), 5) olive-gray muddy layer, 6) pale-brown sandy layer, and 7) yellow sandy layer, and 8) 2011 earthquake-induced turbidite, based on the characteristics of sedimentary facies, petrography, grainsize, mineral assemblages (XRD) and vertical variation of chemistry (micro-XRF). There are many tephra-fall layers but most of them are extra-basinal origin, i.e., of other volcanoes than Adatara and Bandai. Gm is usually a few millimeters to centimeters thick, blue-gray color, homogenized, and finer than background sediments. Gs is accompanied with coarser subunits and thicker than Gm. Especially, Gm/Gs contain pyrite, sulfate minerals and smectite, and are characterized by high sulfur contents. Bm and Bs are 1 to 6 cm thick and are normally

  7. Japan.

    ERIC Educational Resources Information Center

    Jones, Savannah C.

    Materials for a secondary level, interdisciplinary social studies course on Japan are divided into introductory information, 14 classroom units, and study and evaluation materials. Introductory material includes lists of objectives and skills, an outline of Japanese history, and an explanation of Japan's name and flag. The units cover the…

  8. Japan.

    ERIC Educational Resources Information Center

    Jones, Savannah C.

    Materials for a secondary level, interdisciplinary social studies course on Japan are divided into introductory information, 14 classroom units, and study and evaluation materials. Introductory material includes lists of objectives and skills, an outline of Japanese history, and an explanation of Japan's name and flag. The units cover the…

  9. Japan

    ERIC Educational Resources Information Center

    Hawkins, John N.

    1986-01-01

    Analyzes the intergroup relations in Japanese society and Japan's educational system. Challenges the view that Japan is a homogeneous society by presenting the various forms of discrimination against Koreans, Ainu, and the burakumin. Suggests that despite ostracism and isolation, groups can affect public policy and achieve social advancement. (SA)

  10. The influence of strain localisation on spine extrusion dynamics during the 1991-1995 eruption at Unzen volcano (Japan)

    NASA Astrophysics Data System (ADS)

    Wallace, Paul A.; Kendrick, Jackie E.; Ashworth, James D.; Coats, Rebecca; Lamb, Oliver; Miwa, Takahiro; Mariani, Elisabetta; Lavallée, Yan

    2017-04-01

    The eruption of highly viscous magma at lava domes is commonly followed by the extrusion of a spine, a typical manifestation of waning activity marking the cessation of a prolonged eruptive episode. Exogenous dome growth can lead to catastrophic consequences on overall dome stability and thus its understanding is central to the mitigation of associated risks. Spine extrusion during the final stages of the 1991-95 lava dome eruption at Unzen volcano (Japan) has provided a unique opportunity to investigate the contribution of the different deformation textures and varying petrological phenomena associated with magma ascent. The protraction of this dense magmatic plug formed a 6 m wide shear zone consisting of four structurally discrete units including gouge (1), a highly sheared zone (2) to a moderately sheared zone (3) and an undeformed magmatic core (4). We present the first systematic study of the microstructures, mineralogy, crystal stability, geochemistry and crystal size distribution across this shear zone. The data is complimented by laboratory permeability measurements and seismic observations over the extrusion period. The crystal-rich (˜70 vol.%) dacitic spine preserves an abundant record of both brittle and ductile deformation. Gouge material is dominated by cataclastic microstructures with comminution of crystals and formation of conjugate microfractures, a result of loss of cohesion due to friction along the fault. A decrease in crystal size and circularity with increasing shear indicates brittle processes dominate near the spine margins. The porous network varies significantly with pore size decreasing with increasing shear, a result of shear-enhanced compaction, consistent with a decrease in permeability of one order of magnitude. The interaction of crystals (via strain-partitioning) further facilitates in localising stress and strain along the conduit margin leading to crystal-plastic deformation. Electron backscatter diffraction (EBSD) enables the

  11. Andesite Magmas are Produced along Oceanic Arcs where the Crust is Thin: Evidence from Nishinoshima Volcano, Ogasawara Arc, Japan

    NASA Astrophysics Data System (ADS)

    Tamura, Y.; Ishizuka, O.; Sato, T.; Nichols, A. R.

    2015-12-01

    The incentive for this study is the ongoing explosive eruption of Nishinoshima volcano, located about 1,000 km south of Tokyo along the Ogasawara (Bonin) Arc. The straightforward but unexpected relationship presented here relates crustal thickness and magma type in the Izu-Ogasawara Oceanic Arc. Volcanoes along the Ogasawara segment of the arc, which include Nishinoshima, are underlain by thin crust (16-21 km)—in contrast to those along the Izu segment, where the crust is ~35 km thick. Interestingly, andesite magmas are dominant products from the former volcanoes and mostly basaltic lavas erupt from the latter. Why and how do volcanoes on the thin crust erupt andesite magmas? An introductory petrology textbook might answer this question by suggesting that, under decreasing pressure and hydrous conditions, the liquidus field of forsterite expands relative to that of enstatite, with the result that, at some point, enstatite melts incongruently to produce primary andesite melt. According to the hypothesis presented here, however, rising mantle diapirs stall near the base of the oceanic arc crust at depths controlled by the thickness of the overlying crust. Where the crust is thin, as along the Ogasawara segment of the arc, pressures are relatively low, and magmas produced in the mantle wedge tend to be andesitic. Where the crust is thick, as along the Izu segment, pressures are greater, and only basaltic magmas tend to be produced. To examine this hypothesis, JAMSTEC cruise NT15-E02 on the R/V Natsushima took place from 11 June to 21 June 2015 to Nishinoshima. It's present island has an elevation of only ~150 m, but its submarine flanks extend to ocean depths of 2,000-3,000 m, so the great bulk of the volcano is submarine and yet-to-be explored. We present the new hypothesis and its evidence from Nishinoshima based on the primitive lavas collected from the submarine parts of the volcano.

  12. Combined use of repeated active shots and ambient noise to detect temporal changes in seismic velocity: application to Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Hirose, Takashi; Nakahara, Hisashi; Nishimura, Takeshi

    2017-03-01

    Coda-wave interferometry is a technique to detect small seismic velocity changes using phase changes in similar waveforms from repeating natural or artificial sources. Seismic interferometry is another technique for detecting seismic velocity changes from cross-correlation functions of ambient seismic noise. We simultaneously use these two techniques to clarify seismic velocity changes at Sakurajima volcano, one of the most active volcanoes in Japan, examining the two methods. We apply coda-wave interferometry to the records of repeated active seismic experiments conducted once a year from 2011 to 2014, and seismic interferometry to the ambient seismic noise data. We directly compare seismic velocity changes from these two techniques. In coda-wave interferometry analyses, we detect significant seismic velocity increases between 2011 and 2013, and seismic velocity decreases between 2013 and 2014 at the northern and eastern flanks of the volcano. The absolute values are at a maximum 0.47 ± 0.06% for 2-4 Hz, 0.24 ± 0.03% for 4-8 Hz, and 0.15 ± 0.03% for 8-16 Hz, respectively. In seismic interferometry analyses, vertical-vertical cross-correlations in 1-2, 2-4, and 4-8 Hz bands indicate seismic velocity increases and decreases during 3 years of 2012-2014 with the maximum amplitudes of velocity change of ±0.3% for 1-2 Hz, ±0.4% for 2-4 Hz, and ±0.2% for 4-8 Hz, respectively. Relative velocity changes indicate the almost annual change. These periodical changes are well matched with volcano deformation detected by GNSS receivers deployed around the volcano. We compare the results from coda-wave interferometry with those from seismic interferometry on the shot days and find that most of them are consistent. This study illustrates that the combined use of coda-wave interferometry and seismic interferometry is useful to obtain accurate and continuous measurements of seismic velocity changes.[Figure not available: see fulltext.

  13. Magnetization intensity mapping on Unzen Volcano, Japan, determined from high-resolution, low-altitude helicopter-borne aeromagnetic survey

    NASA Astrophysics Data System (ADS)

    Okubo, Ayako; Tanaka, Yoshikazu; Utsugi, Mitsuru; Kitada, Naoto; Shimizu, Hiroshi; Matsushima, Takeshi

    2005-08-01

    On September 18, 2002, we conducted a high-resolution, low-altitude helicopter-borne aeromagnetic survey at two flight altitudes, using spiral trajectories for the first time, over Unzen Volcano in the framework of the Unzen Scientific Drilling Project (USDP). This study obtained more detailed and new information than the previous aeromagnetic studies in Unzen volcano about the geological features, for understanding the history and eruption mechanism of the Unzen volcano. Therefore, we conducted a magnetization intensity mapping on the volcano, on the assumption that the magnetic anomalies are caused by the terrain magnetized in the same direction as the present Earth's magnetic field and the magnetization intensity varies only laterally. This map shows good agreement with the geologic features, especially the hydrothermal alteration zone and the collapsed pyroclastic deposits. In addition, even in the area covered by lavas, the magnetization intensities show various values corresponding to each eruption event. It may be considered that the differences in magnetic properties reflect different oxygen fugacity in rocks during their cooling time period. Local magnetization lows on Heisei-Shinzan suggest that the Heisei lava produced by the 1991-1995 eruption has not yet been cooled enough.

  14. The geochemical and petrological characteristics of prenatal caldera volcano: a case of the newly formed small dacitic caldera, Hijiori, Northeast Japan

    NASA Astrophysics Data System (ADS)

    Miyagi, Isoji; Kita, Noriko; Morishita, Yuichi

    2017-09-01

    Evaluating the magma depth and its physical properties is critical to conduct a better geophysical assessment of magma chambers of caldera volcanoes that may potentially cause future volcanic hazards. To understand pre-eruptive conditions of a magma chamber before its first appearance at the surface, this paper describes the case of Hijiori caldera volcano in northeastern Japan, which emerged approximately 12,000 years ago at a place where no volcano ever existed. We estimated the depth, density, bulk modulus, vesicularity, crystal content, and bulk H_2O content of the magma chamber using petrographic interpretations, bulk and microchemical compositions, and thermodynamic calculations. The chemical mass balance calculations and thermodynamic modeling of the erupted magmas indicate that the upper portion of the Hijiori magmatic plumbing system was located at depths between 2 and 4 km, and had the following characteristics: (1) pre-eruptive temperature: about 780 °C; (2) bulk magma composition: 66 ± 1.5 wt% SiO2; (3) bulk magmatic H_2O: approximately 2.5 wt%, and variable characteristics that depend on depth; (4) crystal content: ≤57 vol%; (5) bulk modulus of magma: 0.1-0.8 GPa; (6) magma density: 1.8-2.3 g/cm3; and (7) amount of excess magmatic H_2O: 11-32 vol% or 48-81 mol%. The range of melt water contents found in quartz-hosted melt inclusions (2-9 wt%) suggests the range of depth phenocrysts growth to be wide (2˜13 km). Our data suggest the presence of a vertically elongated magma chamber whose top is nearly solidified but highly vesiculated; this chamber has probably grown and re-mobilized by repeated injections of a small amount of hot dacitic magma originated from the depth.

  15. Response of a hydrothermal system to magmatic heat inferred from temporal variations in the complex frequencies of long-period events at Kusatsu-Shirane Volcano, Japan

    USGS Publications Warehouse

    Nakano, M.; Kumagai, H.

    2005-01-01

    We investigate temporal variations in the complex frequencies (frequency and quality factor Q) of long-period (LP) events that occurred at Kusatsu-Shirane Volcano, central Japan. We analyze LP waveforms observed at this volcano in the period between 1988 and 1995, which covers a seismically active period between 1989 and 1993. Systematic temporal variations in the complex frequencies are observed in October-November 1989, July-October 1991, and September 1992-January 1993. We use acoustic properties of a crack filled with hydrothermal fluids to interpret the observed temporal variations in the complex frequencies. The temporal variations in October-November 1989 can be divided into two periods, which are explained by a gradual decrease and increase of a gas-volume fraction in a water-steam mixture in a crack, respectively. The temporal variations in July-October 1991 can be also divided into two periods. These variations in the first and second periods are similar to those observed in November 1989 and in September-November 1992, respectively, and are interpreted as drying of a water-steam mixture and misty gas in a crack, respectively. The repeated nature of the temporal variations observed in similar seasons between July and November suggests the existence of seasonality in the occurrence of LP events. This may be caused by a seasonally variable meteoritic water supply to a hydrothermal system, which may have been heated by the flux of volcanic gases from magma beneath this volcano. ?? 2005 Elsevier B.V. All rights reserved.

  16. Simulation of pre-eruptive magma migration and accumulation based on hydrokinetic modeling of magma plumbing system beneath Sakurajima Volcano (Japan)

    NASA Astrophysics Data System (ADS)

    Minami, S.; Iguchi, M.; Mikada, H.; Goto, T.; Takekawa, J.

    2012-12-01

    We numerically simulated a transient magma accumulating process in the magma plumbing system beneath an active Showa crater of Sakurajima Volcano (Japan). Our objective is to find dominant geophysical parameters in the accumulating process before eruption. Geodetic observations showed that a periodic inflation and deflation event had lasted 30 hours before an explosive eruption. Our model consists of shallower gas and deeper magma reservoirs connected by a volcanic conduit as inferred from the past geophysical observations. A pressure difference between the two reservoirs forces the magma to move from the deeper up to the shallower reservoir. We assumed a constant rate of magma supply to the deeper reservoir as an input to the magma plumbing system. In a cylindrical volcanic conduit, a viscous multiphase magma flow is demonstrated by 1-dimentional transient flow simulations with the effects of the relative motion of gas in magma, the exsolution of volatiles in melt, the crystallization of microlites in groundmass, the change in height of magma head, etc. As a result, we found that the radius of the volcanic conduit, the magma supply rate and the compressibility of the deeper reservoir are key parameters to reproduce the observed volumetric variations before the eruption. These three parameters are estimated about 13 m, 3.5 m3/s and 10 GPa, respectively by means of a least squares method. Finally, the inflation and deflation event observed before the eruption are well reproduced. We would like to propose our numerical model as one of quantitative simulation methods that could be applied to the future eruptive events not only at Sakurajima Volcano but for the other volcanoes. Some of parameters of the magma plumbing system need to be fixed as in this study should be discussed in terms of the sensitivity in the analysis at the time of the application.

  17. Stress-induced spatiotemporal variations in anisotropic structures beneath Hakone volcano, Japan, detected by S wave splitting: A tool for volcanic activity monitoring

    NASA Astrophysics Data System (ADS)

    Honda, Ryou; Yukutake, Yohei; Yoshida, Akio; Harada, Masatake; Miyaoka, Kazuki; Satomura, Mikio

    2014-09-01

    Hakone volcano, located at the northern tip of the Izu-Mariana volcanic arc, Japan, has a large caldera structure containing numerous volcanic hot springs. Earthquake swarms have occurred repeatedly within the caldera. The largest seismic swarm since the commencement of modern seismic observations (in 1968) occurred in 2001. We investigated the anisotropic structure of Hakone volcano based on S wave splitting analysis and found spatiotemporal changes in the splitting parameters accompanying the seismic swarm activity. Depth-dependent anisotropic structures are clearly observed. A highly anisotropic layer with a thickness of ~1.5 km is located beneath the Koziri (KZR) and Kozukayama (KZY) stations. The anisotropic intensity in the region reaches a maximum of 6-7% at a depth of 1 km and decreases markedly to less than 1% at a depth of 2 km. The anisotropic intensity beneath Komagatake station (KOM) decreases gradually from a maximum of 6% at the surface to 0% at a depth of 5 km but is still greater than 2.5% at a depth of 3 km. At KZY, the anisotropic intensity along a travel path of which the back azimuth was the south decreased noticeably after the 2001 seismic swarm activity. During the swarm activity, tilt meters and GPS recorded the crustal deformation. The observed decrease in anisotropic intensity is presumed to be caused by the closing of microcracks by stress changes accompanying crustal deformation near the travel path.

  18. Is uplift of volcano clusters in the Tohoku Volcanic Arc, Japan, driven by magma accumulation in hot zones? A geodynamic modeling study

    NASA Astrophysics Data System (ADS)

    George, Ophelia A.; Malservisi, Rocco; Govers, Rob; Connor, Charles B.; Connor, Laura J.

    2016-06-01

    In many volcanic arcs, the rate of tectonic uplift cannot be explained by lithospheric plate motion alone but may be associated with dynamic uplift. Buoyant forces associated with underplated magma bodies lift the upper crust and leads to relatively high rates of topographic change. One such region is northern Honshu, Japan, where Quaternary volcano clusters are spatially associated with uplifted crust and isostatic gravity anomalies. Axisymmetric inversion of Bouguer gravity data for the Sengan volcano cluster shows that these gravity anomalies can be modeled by 30 km radius bodies emplaced at ˜15 km depth. Axisymmetric, finite element models, generated using GTECTON, of a layered Earth representative of the Tohoku crust indicate that the deformation of these midcrustal intrusions produces elevated topography on the surface directly above the intrusion that is bounded by a shallow peripheral trough. The wavelengths of vertical deformation produced by these bodies are sensitive to the thickness of the models' elastic layer and relatively insensitive to the models' rheology. This suggests that the amplitude of the vertical deformation represents a trade-off between the size of the intrusion and the thickness of the elastic layer and is less strongly influenced by the rheology of the lithosphere into which the bodies are emplaced. Our results are consistent with hot zone and hot finger models for the arc and indicate that Tohoku Volcanic Arc features such as gravity anomalies and uplifted basement are related to crustal magma intrusions and hot zones rather than directly related to mantle processes.

  19. Heterogeneities in the magma chambers of monogenetic volcanoes revealed by melt inclusions from the Higashi-Izu Monogenetic Volcanic Field, Japan

    NASA Astrophysics Data System (ADS)

    Wysoczanski, R. J.; Nichols, A. R.; Tani, K.; Tamura, Y.; Baker, J. A.; Tatsumi, Y.

    2011-12-01

    The Higashi-Izu Monogenetic Volcanic Field (HIMVF) consists of 70 subaerial monogenetic volcanoes on the north-eastern coast of the Izu Peninsula, Japan, and a further 50 submarine monogenetic volcanoes that extend offshore to the island of Izu-Oshima, a volcano on the volcanic front of the Izu-Bonin (IB) Arc. The HIMVF has been active from 0.3 Ma until the present day. The transition from polygenetic volcanism to monogenetic volcanism on the Izu Peninsula around this time is believed to be related to a change in the stress field after the Izu Peninsula tectonic block began to collide with the Honshu Arc (Hasebe et al., 2001, B. Volcanol., 63, 377-86). Major, trace and volatile (H2O, CO2, S, Cl) element concentrations have been measured in 116 inclusions hosted in olivines from scoria erupted by two of the basaltic monogenetic volcanoes, Sukumoyama and Takatsukayama. The volcanoes are located 5 km apart, trending across the IB Arc, and erupted at ~0.27 Ma, early in the history of activity in the HIMVF. The geochemical characteristics of the inclusions have led to the following findings. Firstly, the inclusions, consistent with whole rocks data from the HIMVF, indicate that the HIMVF has a geochemical affinity with the IB rear-arc, being more enriched in large-ion lithophile elements (LILE) high field strength elements (HFSE) and rare earth elements (REE) than the volcanic front. Secondly, some of the inclusions preserve compositions that have not been previously seen in rocks from the IB Arc. Most of the inclusions are normal IB low TiO2 (0.81 to 1.18 wt.%) high Al2O3 (15.67 to 19.34 wt.%) (low TiO2-HABs), however, 20 inclusions have high TiO2 (1.11 to 2.19 wt.%), low Al2O3 (11.75 to 14.04 wt.%) (high TiO2-LABs), and three have been found to contain high TiO2 (1.34 to 1.61 wt.%) and high Al2O3 (16.06 to 19.14 wt.%). There are cases where a high TiO2-LAB inclusion occurs in the same host crystal as low TiO2-HAB inclusions. The Takatsukayama high TiO2-LABs are also

  20. Klyuchevskaya Volcano

    NASA Image and Video Library

    2017-09-27

    Shiveluch volcano on Russia’s Kamchatka Peninsula. This is a false-color satellite image, acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on March 10, 2010. To download a full high res version of this image and to learn more go to: earthobservatory.nasa.gov/NaturalHazards/view.php?id=43103 Credit: NASA Earth Observatory image by Jesse Allen and Robert Simmon, based on data from the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Instrument: Terra - ASTER For more information about the Goddard Space Flight Center go here: www.nasa.gov/centers/goddard/home/index.html

  1. Nature of low frequency earthquakes observed at Asama volcano, Japan: Time variation of wave parameters and hypocenter distribution

    NASA Astrophysics Data System (ADS)

    Oikawa, J.; Ida, Y.

    2007-12-01

    Long period (LP) events called N-type earthquakes are typical phenomena observed at many active volcanoes, such as Kusatsu-Shirane, Asama, Tokachi-dake volcanoes. They are probably related to activities of magma, ground water or volcanic gas and many source mechanisms such as resonance of fluid cracks or spheres are proposed. In this study, we analyze the LP events observed at Asama volcano in Dec. 1-10, 1996, to reveal their source process with the high quality data obtained by the seismic network close to the summit crater of the volcano. We observed 112 N-type earthquakes during the period. The waveforms of these events seem to be a quasi-monochromatic oscillation with gradually decreasing amplitude. The spectrum has a dominant peak at 1.6-7.2 Hz, most of which make a group (Group 0) in which the dominant peak changes from 2.0 Hz to 1.6 Hz gradually, indicating that the scale or the physical properties of the LP source changes gradually if we accept the resonance model. Other groups appear in Dec. 3-6 (Group 1) and in Dec. 9-10 (Group 2) in which the dominant peak changes from 7.2 Hz to 1.4 Hz and 4.3 Hz to 1.6 Hz gradually, respectively. This indicates that two or more sources of the N-type earthquakes exist simultaneously. Attenuation factors have a positive but weak correlation with the frequency of dominant peaks. Hypocenters of the events determined by the travel time of the first motion are concentrated within a depth of 300 m underneath the summit crater and are distributed in the shallow part of the region where B-type earthquakes occur. The events of Group 0 are concentrated underneath the southwest side of the crater, and the events of Group 1 and 2 distribute in the east side of the crater.

  2. Isolation of aquatic yeasts with the ability to neutralize acidic media, from an extremely acidic river near Japan's Kusatsu-Shirane Volcano.

    PubMed

    Mitsuya, Daisuke; Hayashi, Takuya; Wang, Yu; Tanaka, Mami; Okai, Masahiko; Ishida, Masami; Urano, Naoto

    2017-07-01

    The Yukawa River is an extremely acidic river whose waters on the east foot of the Kusatu-Shirane Volcano (in Gunma Prefecture, Japan) contain sulfate ions. Here we isolated many acid-tolerant yeasts from the Yukawa River, and some of them neutralized an acidic R2A medium containing casamino acid. Candida fluviatilis strain CeA16 had the strongest acid tolerance and neutralizing activity against the acidic medium. To clarify these phenomena, we performed neutralization tests with strain CeA16 using casamino acid, a mixture of amino acids, and 17 single amino acid solutions adjusted to pH 3.0, respectively. Strain CeA16 neutralized not only acidic casamino acid and the mixture of amino acids but also some of the acidic single amino acid solutions. Seven amino acids were strongly decomposed by strain CeA16 and simultaneously released ammonium ions. These results suggest strain CeA16 is a potential yeast as a new tool to neutralize acidic environments. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  3. Continuous survey of color and glass composition of ash particles by automatic sampling system at Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Shimano, T.; Iguchi, M.; Miki, D.

    2013-12-01

    Activities at many subaerial volcanoes in subduction regions are characterized by ash emissions. Sakurajima volcano is also characterized by long-term successive ash emission such as vulcanian and strombolian eruptions that show many transitional features in eruption types, intensity of explosion or seismicity, amount and grain size of ash, height of plume, duration and interval of eruption, etc. In contrast, however, Plinian eruptions have occurred several times even in historical age, such as the 1914 eruption. In 2006, Showa crater of Sakurajima volcano became active since the 1946 eruption that similar ash emitting activity for several years evolved into effusion of large amount of lava. One of the aims of our study is to clarify how eruptions evolve into such larger eruptions from quiescent phase or moderate ash emission. We carried out continuous survey of ash particles of ash emitting eruptions, and here we report some results to reveal and understand transitional features of ash emitting activity. We started collection of ash at Sakurajima volcano in 2008 by establishing automatic sampling system. We developed mobile unmanned apparatus that enables continuous sampling of ash fall, and have been successful in daily collection of samples for five years at a locality 2.3 km from active vent, thus we have collected more than 1500 samples. The temporal change in daily amount of ash fall at this site was consistent with that estimated monthly by manned survey around this volcano. We found several types of ash particles in each of these samples where crystalline and glassy particles, in terms of groundmass crystallinity, are dominant types. We have carried out some analyses that characterize ash samples. Although petrological features are rather complex, chemical composition of matrix glass of particles and color of bulk ash sample in terms of photochrometry show systematic temporal changes in order of date that may be correlated with some geodetic observations

  4. Three-dimensional P-wave velocity structure of Bandai volcano in northeastern Japan inferred from active seismic survey

    NASA Astrophysics Data System (ADS)

    Yamawaki, Teruo; Tanaka, Satoru; Ueki, Sadato; Hamaguchi, Hiroyuki; Nakamichi, Haruhisa; Nishimura, Takeshi; Oikawa, Jun; Tsutsui, Tomoki; Nishi, Kiyoshi; Shimizu, Hiroshi; Yamaguchi, Sosuke; Miyamachi, Hiroki; Yamasato, Hitoshi; Hayashi, Yutaka

    2004-12-01

    The three-dimensional P-wave velocity structure of the Bandai volcano has been revealed by tomographic inversion using approximately 2200 travel-time data collected during an active seismic survey comprising 298 temporary seismic stations and eight artificial shots. The key result of this study is the delineation of a high-velocity anomaly (Vp>4.6 km/s at sea-level) immediately below the summit peak. This feature extends to depths of 1-2 km below sea-level. The near-surface horizontal position of the high-velocity anomaly coincides well with that of a positive Bouguer gravity anomaly. Geological data demonstrate that sector collapses have occurred in all directions from the summit and that the summit crater has been repeatedly refilled with magmatic material. These observations suggest that the high-velocity region revealed in this study is a manifestation of an almost-solidified magmatic plumbing system. We have also noted that a near-surface low-velocity region (Vp<3.0 km/s at sea-level) on the southern foot of the volcano corresponds to the position of volcanic sediments including ash and debris avalanche material. In addition, we have made use of the tomographic results to recompute the hypocenters of earthquake occurring during seismic swarms beneath the summit in 1988 and 2000. Relocating the earthquakes using the three-dimensional velocity model clearly indicates that they predominantly occurred on two steeply dipping planes. Low-frequency earthquakes observed during the swarms in 2000 occurred in the seismic gap between the two clusters. The hypocentral regions of the seismic swarms and the low-frequency earthquakes are close to the higher-velocity zone beneath the volcano's summit. These observations suggest that the recent seismic activity beneath the summit is likely associated with thermal energy being released within the solidifying magmatic plumbing system.

  5. PREFACE: Atomic Spectra and Oscillator Strengths (ASOS9) Atomic Spectra and Oscillator Strengths (ASOS9)

    NASA Astrophysics Data System (ADS)

    Wahlgren, Glenn M.; Wiese, Wolfgang L.; Beiersdorfer, Peter

    2009-05-01

    For the first time since its inaugural meeting in Lund in 1983, the triennial international conference on Atomic Spectroscopy and Oscillator Strengths for Astrophysical and Laboratory Plasmas (ASOS) returned to Lund, Sweden. Lund has been a home to atomic spectroscopy since the time of Janne Rydberg, and included the pioneering work in laboratory and solar spectroscopy by Bengt Edlén, who presented the initial ASOS talk in 1983. The ninth ASOS was hosted by the Lund Observatory and Physics Department of Lund University, 7-10 August 2007, and was attended by 99 registrants. An encouraging sign for the field was the number of young researchers in attendance. This volume of Physica Scripta contains contributions from the invited presentations of the conference. For the first time, papers from the ASOS9 poster presentations have been made feely available online in a complementary volume of Journal of Physics: Conference Series. With these two volumes the character of ASOS9 is more evident, and together they serve as a review of the state of atomic spectroscopy for spectrum analysis and the determination of oscillator strengths and their applications. The goal of ASOS is to be a forum for atomic spectroscopy, where both the providers and the users of atomic data, which includes wavelengths, energy levels, lifetimes, oscillator strengths and line shape parameters, can meet to discuss recent advances in experimental and theoretical techniques and their application to understanding the physical processes that are responsible for producing observed spectra. The applications mainly originate from the fields of astrophysics and plasma physics, which includes fusion energy and lighting research. The oral presentations, all but one of which are presented in this volume, provided an extensive synopsis of techniques currently in use and those that are being planned. New to ASOS9 was the extent to which techniques such as cold, trapped atoms and molecules and frequency combs are

  6. The first discovery of cryptotephra of the catastrophic eruptions of the Baitoushan volcano in the tenth century A.D. in the shelf deposits of the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Akulichev, V. A.; Astakhov, A. S.; Malakhov, M. I.; Aksentov, K. I.; Karabtsov, A. A.; Mar'yash, A. A.; Alatortsev, A. V.

    2016-08-01

    The interlayers of the cryptotephra of different episodes of the catastrophic eruption of the Baitoushan volcano (Paektu-san, Changbaishan-Tianchi) in the 10th century were discovered in the sedimentary cover of Amur Bay in the Sea of Japan by the geochemical and paleomagnetic characteristics. The petrochemistry of the volcanic glass indicates the possible occurrence of pyroclastic material in the B-Tm layer and more recent episodes that have not been identified before in the sediments of the Sea of Japan. The impact of the eruption on the bay environment is noted. It is shown that the medieval state of Balhae occupying vast areas and adjacent to the volcano no longer existed after the more earlier episodes of eruption.

  7. Petrogenesis of mafic and associated silicic end-member magmas for calc-alkaline mixed rocks in the Shirataka volcano, NE Japan

    NASA Astrophysics Data System (ADS)

    Hirotani, Shiho; Ban, Masao; Nakagawa, Mitsuhiro

    2009-06-01

    Eruptive products of the Shirataka volcano (0.9-0.7 Ma) in NE Japan are calc-alkaline andesite-dacite, and are divisible into six petrologic groups (G1-G6). Shirataka rocks possess mafic inclusions—basalt-basaltic andesite, except for G3 and G4. All rocks show mixing and mingling of the mafic and silicic end-members, with trends defined by hosts and inclusions divided into high-Cr and low-Cr types; both types coexist in G1, G2, and G5. Estimated mafic end-members are high-Cr (1120-1170°C, 48-51% SiO2, olv ± cpx ± plg) and low-Cr type magmas (49-52% SiO2, cpx ± plg) except for the Sr isotopic composition. In contrast, the silicic end-members of both types have similar petrologic features (790-840°C, 64-70% SiO2, hbl ± qtz ± px + plg). High-Cr type mafic and corresponding silicic end-members have lower 87Sr/86Sr ratios than the low-Cr ones in each group. The trace element model calculations suggest that the low-Cr type mafic end-member magma is produced through ca. 20% fractional crystallization (olv ± cpx ± plg) from the high-Cr type one with assimilation of granitoids ( r = 0.02-0.05). The silicic magmas are producible through <30% partial remelting of previously emplaced basaltic magma with assimilation of crustal components. The compositional difference between the low-K and medium-K basalts in the Shirataka volcano is mainly attributed to the different degrees of the effect of subduction derived fluid by dehydration of phlogopite.

  8. Determination of temporal changes in seismic velocity caused by volcanic activity in and around Hakone volcano, central Japan, using ambient seismic noise records

    NASA Astrophysics Data System (ADS)

    Yukutake, Yohei; Ueno, Tomotake; Miyaoka, Kazuki

    2016-12-01

    Autocorrelation functions (ACFs) for ambient seismic noise are considered to be useful tools for estimating temporal changes in the subsurface structure. Velocity changes at Hakone volcano in central Japan, where remarkable swarm activity has often been observed, were investigated in this study. Significant velocity changes were detected during two seismic activities in 2011 and 2013. The 2011 activity began immediately after the 2011 Tohoku-oki earthquake, suggesting remote triggering by the dynamic stress changes resulting from the earthquake. During the 2013 activity, which exhibited swarm-like features, crustal deformations were detected by Global Navigation Satellite System (GNSS) stations and tiltmeters, suggesting a pressure increment of a Mogi point source at a depth of 7 km and two shallow open cracks. Waveforms that were bandpass-filtered between 1 and 3 Hz were used to calculate ACFs using a one-bit correlation technique. Fluctuations in the velocity structure were obtained using the stretching method. A gradual decrease in the velocity structure was observed prior to the 2013 activity at the KOM station near the central cone of the caldera, which started after the onset of crustal expansion observed by the GNSS stations. Additionally, a sudden significant velocity decrease was observed at the OWD station near a fumarolic area just after the onset of the 2013 activity and the tilt changes. The changes in the stress and strain caused by the deformation sources were likely the main contributors to these decreases in velocity. The precursory velocity reduction at the KOM station likely resulted from the inflation of the deep Mogi source, whereas the sudden velocity decrease at the OWD station may reflect changes in the strain caused by the shallow open-crack source. Rapid velocity decreases were also detected at many stations in and around the volcano after the 2011 Tohoku-oki earthquake. The velocity changes may reflect the redistribution of hydrothermal

  9. A study of the Taisho lahar generated by the 1926 eruption of Tokachidake Volcano, central Hokkaido, Japan, and implications for the generation of cohesive lahars

    NASA Astrophysics Data System (ADS)

    Uesawa, Shimpei

    2014-01-01

    Understanding the generation mechanisms of lahars is important for improving volcanic hazard assessments. The Taisho lahar (TL) was generated during the 1926 eruption of Tokachidake Volcano, Japan, and was considered a typical snowmelt lahar caused by the runout of hot debris onto a snow-covered slope. A similar mechanism produced a huge mud flow during the 1985 eruption of Nevado del Ruiz, Colombia. However, the origin of water in such lahars remains a controversial topic because the calculated water mass is based on the assumption that all of the snow on the runout area of the TL was melted, although this is much less than the estimated water volume in the TL estimated by previous studies. I have re-examined proximal deposits of the TL and their paleomagnetic characteristics in order to better understand the eruption sequence and formation of the TL. The TL produced two debris avalanche deposits and a surge-like deposit that had relatively high emplacement temperature (~ 350 °C). The deposits are composed of hydrothermally altered andesitic gravel, sand and mud. The high clay content (3-5 wt.% clay in the < 2 mm fraction) and sedimentary characteristics indicate that the flow was a cohesive lahar, most likely induced by collapse of a hydrothermally altered pyroclastic cone (hypocenter). The presence of the surge deposit indicates that the TL was not caused by simple collapse of a cinder cone but by a phreatic explosion that resulted in sector collapse. This suggests that the hydrothermal system was related to the 1926 eruption. The present-day volcano has a large hydrothermal system (1 × 106 m3 water) beneath the active crater. This study indicates that hydrothermal system explosions can trigger cohesive lahars that contain both snow melt and hydrothermal pore water, and this indicates the need to monitor hydrothermal systems.

  10. Hydrothermal system beneath the crater of Tarumai volcano, Japan: 3-D resistivity structure revealed using audio-magnetotellurics and induction vector

    NASA Astrophysics Data System (ADS)

    Yamaya, Yusuke; Mogi, Toru; Hashimoto, Takeshi; Ichihara, Hiroshi

    2009-11-01

    Audio-magnetotelluric (AMT) measurements were recorded in the crater area of Tarumai volcano, northeastern Japan. This survey brought the specific structures beneath the lava dome of Tarumai volcano, enabling us to interpret the relationship between the subsurface structure and fumarolic activity in the vicinity of a lava dome. Three-dimensional resistivity modeling was performed to achieve this purpose. The measured induction vectors pointed toward the center of the dome, implying the topographic effect. However, estimation of the topographic effect showed that the measured vector was not explained only by this effect. This suggested that the distribution of induction vectors still held information of the subsurface structure and could be helpful in determining the geometry of 3-D bodies. The 3-D modeling was based on a quasi-one-dimensional layered structure that included topography. The final model revealed that the andesitic lava dome is characterized by comparatively low resistivity (50 Ωm), and that two conductive bodies (50 and 1-5 Ωm) are present beneath the lava dome. The shallower of these conductors is interpreted as an aquifer, such as a buried crater lake. The deeper, extremely conductive body corresponded to a convecting zone containing rising hydrothermal fluid. The shallower aquifer critically controls the temperature and chemical components of the fumarolic gasses. High-temperature gas supplied from deeper part that encounters the shallow aquifer loses its water-soluble components and heat, resulting in weak and low-temperature fumaroles. In contrast, most of the gas, which ascends outside the area of the shallower aquifer, is released as high-temperature fumaroles. This study provides an insight that the shallow aquifer in the crater area plays a significant role in the property of fumaroles at the volcanic surface.

  11. Explosion Energy of the 2004 Eruption of the Asama Volcano, Central Japan: Inference From Ionospheric Disturbances Observed by a Dense GPS Array

    NASA Astrophysics Data System (ADS)

    Heki, K.

    2006-12-01

    Ionospheric Total Electron Content (TEC) can be easily measured as the phase differences of the L1 and L2 band carrier waves from Global Positioning System (GPS) satellites. Ionospheric disturbances measured as TEC changes have been contributing to not only solar-terrestrial studies but also solid earth geophysics, e.g. constraining the source process of the 2004 Sumatra Earthquake (Heki et al., JGR, 2006). Here I present a new application of GPS-TEC, i.e. estimation of the explosion energy of a volcanic eruption (Heki, GRL, 2006). The Asama Volcano, Central Japan, started eruptive activity at 11:02 UT on September 1, 2004, with a vulcanian explosion associated with strong airwaves. The Japanese dense GPS array GEONET recorded ionospheric disturbances as N-shaped changes in TEC approximately 12 minutes after the eruption. The disturbance had a period of 1.25 minutes and propagated as fast as about 1.1 km/s, suggesting its origin as the acoustic wave generated by the explosion. By comparing the disturbance amplitudes with those by a surface mine blast with a known energy (Calais et al., GJI, 1998), the overall Asama explosion energy is inferred to be equivalent to 1.2e14 Joule, about one third of the energy reported for the 1938 eruption (Minakami, BERI, 1942). Energy of the airwave can be estimated following Johnson (JVGR, 2003), assuming that the disturbance is a part of the spherical wave propagated from the volcano. We thus obtained the value 9.0e6 Joule, a typical value of airwave energies associated with volcanic eruptions. This new technique would complement past methods based on observations of mass deficits, near-field measurements of airwaves, etc, and may contribute to mitigation of volcanic hazards.

  12. Volcanic gas composition changes during the gradual decrease of the gigantic degassing activity of Miyakejima volcano, Japan, 2000-2015

    NASA Astrophysics Data System (ADS)

    Shinohara, Hiroshi; Geshi, Nobuo; Matsushima, Nobuo; Saito, Genji; Kazahaya, Ryunosuke

    2017-02-01

    The composition of volcanic gases discharged from Miyakejima volcano has been monitored during the intensive degassing activity that began after the eruption in 2000. During the 15 years from 2000 to 2015, Miyakejima volcano discharged 25.5 Mt of SO2, which required degassing of 3 km3 of basaltic magma. The SO2 emission rate peaked at 50 kt/day at the end of 2000 and quickly decreased to 5 kt/day by 2003. During the early degassing period, the volcanic gas composition was constant with the CO2/SO2 = 0.8 (mol ratio), H2O/SO2 = 35, HCl/SO2 = 0.08, and SO2/H2S = 15. The SO2 emission rate decreased gradually to 0.5 kt/day by 2012, and the gas composition also changed gradually to CO2/SO2 = 1.5, H2O/SO2 = 150, HCl/SO2 = 0.15, and SO2/H2S = 6. The compositional changes are not likely caused by changes in degassing pressure or volatile heterogeneity of a magma chamber but are likely attributed to an increase of hydrothermal scrubbing caused by large decrease of the volcanic gas emission rate, suggesting a supply of gases with constant composition during the 15 years. The intensive degassing was modeled based on degassing of a convecting magma conduit. The gradual SO2 emission rate that decrease without changes in volcanic gas composition is attributed to a reduction of diameter of the convecting magma conduit.

  13. Fractal analysis of the fracture strength of lava dome material based on the grain size distribution of block-and-ash flow deposits at Unzen Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Suzuki-Kamata, Keiko; Kusano, Takashi; Yamasaki, Kazuhito

    2009-10-01

    A fractal theory of rock fragmentation is applied to block-and-ash flow deposits from the Fugendake dome, Unzen Volcano, Kyushu, Japan, in order to analyze the material strength and the energy required for size reduction of the source lava dome. Two fractal dimensions h and Ds, which are mutually interchangeable, represent the relative strength and energy for particles reduced to a given size. They can be theoretically estimated from the power relations of a reference grain size to the cumulative mass and number of fragments smaller than that size. The Unzen-Fugendake block-and-ash flow deposits have been further modified by size sorting and secondary fragmentation that occurred during flowage, so that the h value decreases (or Ds value increases) with increasing distance from the source. Coarse, reversely graded deposits are, however, found to retain the original size population relatively well. The Ds values estimated from deposits of this type are compatible with those previously reported from decompression-fragmentation experiments conducted on the same dome material. The employed fractal approach could thus give insights into the potential mode of dome collapse that generates block-and-ash flows.

  14. Izu-Oshima volcano, Japan: nine years of geochemical monitoring by means of CO_{2} soil diffuse degassing

    NASA Astrophysics Data System (ADS)

    Hernández, Pedro A.; Mori, Toshiya; Notsu, Kenji; Morita, Masaaki; Padrón, Eleazar; Onizawa, Shin'ya; Melián, Gladys; Sumino, Hirochicka; Asensio-Ramos, María; Nogami, Kenji; Pérez, Nemesio M.

    2016-04-01

    Izu-Oshima is a 15×9 km active volcanic island located around 100 km SSW of Tokyo. The centre of the island is occupied by a caldera complex with a diameter of 3 km. A large post-caldera cone known as Mt. Mihara is located at the south-western quadrant of the caldera. Izu-Oshima has erupted 74 times, consisting mainly in fissure eruptions, both inside and outside of the caldera. The last eruption of Izu-Oshima occurred in 1986. Since 2007, seven soil gas surveys have been carried out to investigate the spatial and temporal evolution of diffuse CO2 emission from this volcanic system and to identify those structures controlling the degassing process. Diffuse CO2 emission surveys were always carried out following the accumulation chamber method. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. The location of the CO2 anomalies has always shown a close relationship with the structural characteristics of the volcano, with most of the gas discharged from the rim of the summit crater. Temporal evolution of diffuse CO2 emission rate from Mt. Miharayama has shown a good temporal correlation with the seismicity recorded in and around Izu Oshima island during the period of study. The two peaks of seismic activity occur when highest CO2 diffuse emissions were computed, March 2007, August 2010 and July 2011, may be associated with fluid pressure fluctuations in the volcanic system due to the seismicity. In order to strength the contribution of deep seated gases to the diffuse emission, we performed carbon isotopic analysis of soil gas samples at selected sites during 2010, 2013 and 2015 surveys. At isotopic compositions lighter than ˜- 6‰ the soil CO2 effluxes were always low, while at heavier isotopic compositions an increasing number of points are characterized by relatively high soil CO efflux as a consequence of the addition of the hydrothermal CO2 source. Soil CO2 efflux peak values (xBackground) showed also a

  15. Behavior of fluorine and chlorine in volcanic ash of Sakurajima volcano, Japan in the sequence of its eruptive activity

    NASA Astrophysics Data System (ADS)

    Nogami, K.; Iguchi, M.; Ishihara, K.; Hirabayashi, J.-I.; Miki, D.

    2006-05-01

    At Sakurajima volcano, strombolian eruptions forerun vulcanian explosions, and volcanian explosions are often followed by continuous ash eruptions. Change in the mode of its eruptive activity is drastic and release of volatiles from magma corresponding to its eruptive activity is examined by determination of fluorine and chlorine in volcanic ash. The F contents of all the ash samples are markedly higher than the arithmetic mean value of Japanese volcanic rocks (ca. 300 μg/g). Further, the water-soluble Cl contents of almost all the ash samples are also extremely higher than those of Japanese volcanic rocks (less than 50 μg/g). This is attributed to fixation of F and Cl in hot gas onto the volcanic ash particles in the crater and/or eruption plumes. The differences in those contents among the "strombolian eruption"-, "vulcanian explosion"- and "continuous ash eruption" groups are significant, which implies that hot gas rich in F and Cl are issued during strombolian eruptions, while those halogens are less concentrated in hot gas after strombolian eruptions. The water-insoluble Cl content of the "strombolian eruption" group is significantly higher than those of the other groups. This result implies that Cl and the other volatiles are intensely released from magma during the doming period before vulcanian eruptions. Yet, it is inferred that continuous ash eruption is the final phase of vulcanian one.

  16. Landslides triggered by April 2016 Kumamoto Earthquake, Japan

    NASA Astrophysics Data System (ADS)

    Fukuoka, Hiroshi; Bhoopendra, Dabycharun; Sakai, Naoki; Sassa, Kyoji; Dang, Khang

    2017-04-01

    Kumamoto prefecture, Japan was rattled by consecutive earthquakes of M6.5 on April 14 and M7.3 on April 16, 2016. These unusual fore-shock and main-shock claimed fifty casualties, of which ten persons were killed by landslides. The second quake recorded maximum PGA of 1,362 gal, and triggered a number of landslides around Mt. Aso, an active volcano with one of the largest scale caldera. Geospatial Information Authority of Japan interpreted airphotos of the affected area and found at least 750 landslides. Based on the reconnaissance and joint field investigation of ICL and the Japan Landslide Society, those landslides are classified into following 3 types; (1) shallow and deep disrupted landslides on steep slopes mostly on the caldera rim or cliffs, (2) deep-seated and fluidized landslides on gentler slopes showing long run-out distance; (3) debris flows without antecedent precipitation. Soil sampled from landslide sites showed higher maximum moisture content values which 100 - 200 %. It is contributed by heavily weathered "kuroboku" soils containing halloysites. Constant volume direct shear tests and undrained cyclic loading ring shear tests were conducted to reveal their long run-out mechanism.

  17. Tephrostratigraphy during 3000 years recorded in the sedimentary sequence of Beppu Bay, central Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Takemura, K.; Yamada, K.; Kuwae, M.; Yamamoto, M.; Danhara, T.

    2012-12-01

    The tephrostratigraphy around Beppu Bay, central Japan, is investigated using a 9m-long sedimentary core (KT09-3) collected in 2009 with a piston corer. Beppu Bay is located to the east of active volcanic region in Kyushu Island in southwest Japan. Eruptive history of their active volcanoes and widespread tephra records may be preserved in the sedimentary sequence in bay environment. A method to determine the down-hole content of volcanic glass was used in this study. This method consists of four steps: (1) continuous measurement of magnetic susceptibility with lithological observation of sediments, (2) systematic separation of the volcanic glass particles from samples taken at close intervals, and the determination of relative concentration; (3) mineral assemblages counted in the size of 63-125 micro meter fraction; (4) precise measurement of the refractive indices of the separated glass particles. A refractive index measuring system (RIMS) based on the thermal immersion method permitted quick and accurate measurement of the refractive index of a large number of samples. Core (KT09-3) is one of fourteen piston and gravity cores which were retrieved at the center of the basin. Correlation of cores was conducted using sand and silt seams related by events such as turbidite or flood or volcanic ash air fall, and the age-depth model was created by wiggle-matching of forty-two AMS radiocarbon dates from bivalve mollusk shells and excess Pb-210 and Cs-137 concentrations (Kuwae et al., 2012). The sedimentation rates were 230-300 cm/ky. Core is composed of massive diatomaceous clays with 18 event sediments of coarse fractions. Two distinct volcanic ash horizons and several cryptically deposited horizons are found within the sequence. Upper distinct volcanic ash of 509.2 cm depth is composed of many volcanic glasses and heavy minerals of Opx and Cpx with GHb and BHb. Most of volcanic glasses have characteristic high refractive index of about 1.559. This tephra is

  18. Multiple-pressure-source model for ground inflation during the period of high explosivity at Sakurajima volcano, Japan - Combination analysis of continuous GNSS, tilt and strain data -

    NASA Astrophysics Data System (ADS)

    Hotta, Kohei; Iguchi, Masato; Ohkura, Takahiro; Yamamoto, Keigo

    2016-01-01

    We herein propose a three-pressure-source model for ground inflation with highly eruptive activity at the Showa crater of Sakurajima volcano, Japan. We applied a model of stacked spherical sources to continuous combined geodetic data from a global navigation satellite system, tilt and strainmeters. The data were recorded during ground inflation throughout an eruptive episode that began in October 2011 and ended in March 2012. Using a genetic algorithm, we obtained the locations and volumes of three sources. A pressure source analysis of ground inflation during the period from October 2011 to March 2012 revealed inflation sources to be located at a depth of 9.6 km beneath Aira caldera (A-source) and 3.3 km beneath Kita-dake (K-source), and a shallow deflation source is located at a depth of 0.7 km beneath Minami-dake (M-source). The A-source corresponds to the main magma reservoir at a depth of 10 km beneath the Aira caldera inferred by previous geophysical studies. The K-source is a-reservoir of Sakurajima volcano, where magma intrudes from the main magma reservoir beneath the Aira caldera during the first stage of eruptive activity. The M-source is the uppermost part of a conduit from the K-source to the summit and the Showa crater. Magma injection into the A-source started in mid-November 2011, instantly triggering the migration of increased volumes of magma from the A-source to the K-source. Approximately one month later, in mid-December 2011, an increased volume of magma started migrating from the K-source to the M-source and finally erupted at the surface. The accumulation rate for the A-source is comparable to the magma supply rate for the past 100 years (0.8 to 1.6 × 107 m3). The three-pressure-source model was applied to inflation events before the 2011 event in order to reconstruct the magma migration process. Applying our source model to earlier activity phases, we found that injected magma from the A-source remained at the K-source and a small amount of

  19. A Mechanism For Production Of Calc-alkalic And Tholeiitic Magma Series In Zao Volcano, NE Japan (II) - Sr Isotope Micro-analysis Of Plagioclase Phenocrysts

    NASA Astrophysics Data System (ADS)

    Takahashi, T.; Hirahara, Y.; Tatsumi, Y.; Kimura, J.; Ban, M.

    2006-12-01

    It was discussed from the investigation of bulk rock chemical compositions and isotopes ratio that the origin magma or material of calc-alkalic series (CA) and tholeiitic series (TH) from Zao volacano, NE Japan was several necessity (Hirahara et al., 2006). Consequently, we paid attention to Sr isotope ratio of phenocrystic minerals in volcanic rocks, because it can be thought to recorded such magmatic processes, and proposed a mechanism for producing these two magma series based on data obtained by Sr isotopic micro-analyses of plagioclase in volcanic rocks from Zao Volcano. The Sr isotope micro-analyses were performed by two methods. One is the Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometry. The ablate crater size is 0.2mm. Other one is combined method of microdrilling and Thermal Ionization Mass Spectrometey. The microdrilling is the sampling technique of drilling a sample mechanically with a small drill and collecting the sample powder milled. The diameter at the tip of the drills used for sampling is 0.1 and 0.27mm. The collected sample powder was dissolved with acid, and Sr was separated using micro-columns Sr selective resin. Sr isotope measurement was carried out on the Thermal Ionization Mass Spectrometer. Core part of plagioclases in CA has widely An% and Sr isotope ratio (52 ~ 93 and 0.7035 ~ 0.7045), and there are divided into several types by the isotopical and compositional characteristics. Especially, plagioclase of most high An% (90 ~ 93) type in CA shows the lowest Sr isotope ratio (0.7035 ~ 0.7037). On the other hand, plagioclase in TH possesses relatively narrow range of An% and Sr isotope ratio (85 ~ 95 and 0.7042 ~ 0.7045), and there is a tendency that Sr isotope ratio slightly increase with decreasing An%. Results of Sr isotope micro-analyses show that CA formed by magma mixing between isotopically depleted basalt magma and isotopically enriched felsic magma. On the other hand, it shows that the primary basalt magma

  20. Variation of the grain compositions in the ash from the 2011 eruption of Shinmoedake, Kirishima volcano, Japan: insights into the conduit processes

    NASA Astrophysics Data System (ADS)

    Oishi, M.; Vinet, N.; Geshi, N.; Shinohara, H.

    2012-04-01

    We determined the grain and chemical compositions of the tephra emitted from the 2011 eruption series of Shinmoedake, Kirishima volcano. The main eruption types that have been recorded are sub-plinian and vulcanian eruptions. As the main result, we found that the products from both eruption types, sub-plinian and vulcanian, have similar grain and chemical compositions. Shinmoedake, one of the eruptive centers of Kirishima volcanoes located in southern Kyushu, Japan, repeated eruptions from January to September 2011. The eruption series started by a phreato-magmatic explosion in January 19, followed by sub-plinian eruptions on January 26-27, extrusion of lava that filled the summit crater, vulcanian eruptions since the end of January, and minor ash emissions. We collected on-site ash samples derived from all types of eruptions during each event. This provides a rare chance to investigate the characteristics of the eruptive products through time and the possible correlations with the eruption style. We observed color, shape, and vesicularity of the grains in the range 0.25-0.50 mm in diameter, using the optical stereoscopic microscope and SEM. Juvenile materials, with fresh morphology, are classified into five types of grains based on their vesicularity and color: P (light-colored pumice), S (dark-colored scoria), WG (white glassy dense block), GG (gray glassy dense block), and BG (black glassy dense block). For each eruption, we counted the number of grains of each type among an original population of 200 grains (referred hereafter to as 'ash sample'). The five types of grains are found in every ash sample analyzed from all types of eruptions, although the proportion is variable. The proportion of highly-vesicular grains (sum of P and S types) increased from 14% (phreato-magmatic explosion of January 19) to 26.5% (sub-plinian eruption of January 26), and then decreased and fluctuated between 2-25.5% (vulcanian eruptions from February to August). The groundmass of

  1. 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.

  2. The Lyman-α Solar Telescope (LST) for the ASO-S mission

    NASA Astrophysics Data System (ADS)

    Li, Hui

    The Lyman-α (Lyα) Solar Telescope (LST) is one of the payloads for the proposed Space-Borne Advanced Solar Observatory (ASO-S). LST consists of a Solar Disk Imager (SDI) with a field-of-view (FOV) of 1.2 R⊙ (R⊙ = solar radius), a Solar Corona Imager (SCI) with an FOV of 1.1 - 2.5 R⊙, and a full-disk White-light Solar Telescope (WST) with the same FOV as the SDI, which also serves as the guiding telescope. The SCI is designed to work in the Lyα (121.6 nm) waveband and white-light (for polarization brightness observation), while the SDI will work in the Lyα waveband only. The WST works in both visible (for guide) and ultraviolet (for science) broadband. The LST will observe the Sun from disk-center up to 2.5 R⊙ for both solar flares and coronal mass ejections with high tempo-spatial resolution

  3. The Lyman-alpha Solar Telescope for the ASO-S

    NASA Astrophysics Data System (ADS)

    Li, Hui

    2015-08-01

    The Lyman-alpha Solar Telescope (LST) is one of the payloads for the proposed Space-Borne Advanced Solar Observatory (ASO-S). LST consists of a Solar Disk Imager (SDI) with a field-of-view (FOV) of 1.2 Rsun, a Solar Corona Imager (SCI) with an FOV of 1.1 - 2.5 Rsun, and a full-disk White-light Solar Telescope (WST) with an FOV of 1.2 Rsun, which also serves as the guiding telescope. The SCI is designed to work at the Lyman-alpha waveband and white-light, while the SDI will work at the Lyman-alpha waveband only. The WST works both in visible (for guide) and ultraviolet (for science) white-light. The LST will observe the Sun from disk-center up to 2.5 solar radii for both solar flares and coronal mass ejections. In this presentation, I will give an introduction to LST, including scientific objectives, science requirement, instrument design and current status.

  4. Comparison of eruptive and intrusive samples from Unzen Volcano, Japan: Effects of contrasting pressure temperature time paths

    NASA Astrophysics Data System (ADS)

    Almberg, L. D.; Larsen, J. F.; Eichelberger, J. C.; Vogel, T. A.; Patino, L. C.

    2008-07-01

    Core samples from the conduit of Unzen Volcano, obtained only 9 years after cessation of the 1991-1995 eruption, exhibit important differences in physical characteristics and mineralogy, and subtle differences in bulk chemistry from erupted samples. These differences in the conduit samples reflect emplacement under a confining pressure where about half of the original magmatic water was retained in the melt phase, maintenance at hypersolidus temperature for some unknown but significant time span, and subsequent subsolidus hydrothermal alteration. In contrast, magma that extruded as lava underwent decompression to 1 atm with nearly complete loss of magmatic water and cooling at a sufficiently rapid rate to produce glass. The resulting hypabyssal texture of the conduit samples, while clearly distinct from eruptive rocks, is also distinct from plutonic suites. Given the already low temperature of the conduit (less than 200 °C, [Nakada, S., Uto, K., Yoshimoto, M., Eichelberger, J.C., Shimizu, H., 2005. Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP), Sci. Drill., 1, 18-22]) when it was sampled by drilling, this texture must have developed within a decade, and perhaps within a much shorter time, after emplacement. The fact that all trace-element concentrations of the conduit and the last-emplaced lava of the spine, 1300 m above it, are identical to within analytical uncertainty provides strong evidence that both were produced during the same eruption sequence. Changes in conduit magma that occurred between emplacement and cooling to the solidus were collapse of vesicles from less than or equal to the equilibrium value of about 50 vol.% to about 0.1 vol.%; continued resorption of quartz and reaction of biotite phenocrysts due to heating of magma prior to ascent by intruding mafic magma; breakdown of hornblende; and micro-crystallization of rhyolitic melt to feldspar and quartz. Subsolidus changes were deposition of calcite and

  5. Izu-Oshima volcano, Japan: ten years of geochemical monitoring by means of CO2 soil diffuse degassing

    NASA Astrophysics Data System (ADS)

    Hernandez Perez, P. A.; Mori, T.; Notsu, K.; Morita, M.; Padron, E.; Onizawa, S.; Melián, G.; Sumino, H.; Asensio-Ramos, M.; Nogami, K.; Yamane, K.; Perez, N. M.

    2016-12-01

    degassing, and the observed change in the trend may indicate an increase of the seismic-volcanic activity in the next future. Therefore, performing regularly soil CO2 efflux surveys seems to be an effective geochemical surveillance tool Izu-Oshima volcano in order to detect a change in the tendency of the CO2 emission rate in case of future episodes of volcanic unrest.

  6. Mineralogical and Sulfur Isotopic Study on Volcanic Ash of the 2014 Eruption at Ontake Volcano, Central Honshu, Japan

    NASA Astrophysics Data System (ADS)

    Imura, T.; Minami, Y.; Ohba, T.; Takahashi, R.; Imai, A.; Hayashi, S.

    2015-12-01

    Ontake volcano erupted on 27th September 2014. Components in fallout samples were analyzed with microscope, XRD, and SEM-EDS. Pyrophyllite, smectite, muscovite, kaoline group minerals, quartz, cristobalite, tridymite, pyrite, alunite, gypsum and anhydrite were identified from bulk samples. Coarse ash fraction (> 125 µm) consists mainly of siliceous fragments that are intensely altered and contain pyrite and rutile. Weakly-altered dark-gray volcanic rock fragments are also contained. Fine fraction is abundant in euhedral free crystals of alunite and gypsum and aggregates of silica minerals. The 34S/32S ratios of bulk ash samples were analyzed for sulfur leached by water (water-soluble sulfate), gastric (HCl-soluble sulfate), and HNO3 (sulfide). Gastric and HNO3 leaching methods were applied to coarse fraction too. The bulk δ34SCDT compositions of water-soluble sulfate, HCl-soluble sulfate and sulfide were +14.7 ‰, +15.7 ‰, and -4.7 ‰, respectively. Those of HCl-soluble sulfate and sulfide in coarse fraction were +9.1 ‰ and -4.3 ‰, respectively. Paragenesis of quartz and pyrophyllite in single grain implies hydrothermal alteration by hot (> 230 °C), acidic fluid in the sub-volcanic system. The sulfur isotope geothermometry (Ohmoto and Rye, 1979) applied to the pair of water-soluble sulfate and bulk sulfide resulted in 306 °C. Similar temperature (ca. 296 °C) was estimated for the pair of HCl-soluble sulfate and sulfide in bulk ash. The mineralogy and sulfur isotopic study indicate that the 2014 Ontake eruption was derived from an acidic high-temperature (ca. 300 °C) sub-volcanic hydrothermal fluid. However, the estimated temperature for the pair of HCl-soluble sulfate and sulfide from coarse fraction resulted in higher temperature (ca. 482 °C). The coarse fraction preserved the past temperature record of the hydrothermal fluid, because the coarse lithic fragments were derived from pre-existing altered rocks.

  7. Deformation and gravity changes at Izu islands, Japan, prior to, during, and after the 2000 caldera collapse at Miyake-jima volcano

    NASA Astrophysics Data System (ADS)

    Furuya, M.; Okubo, S.; Kimata, F.

    2006-12-01

    Eruptive and caldera-forming activity at Miyakejima volcano, Japan, was accompanied by more than 40 days of seismic swarms, including more than five M6 (or greater) earthquakes, and significant crustal deformation in nearby islands. Here we review ground deformation and gravity changes at Miyakejima and other nearby islands prior to, during, and after the 2000 caldera collapse episode at Miyakejima. While ground displacements observed at Izu-islands can be basically predicted from the Philippine Sea Plate motion in a global perspective, Miyakejima was undergoing inflation if examined locally within the island before the 2000 unrest. It is also known that a couple of leveling benchmarks inside the previous caldera were secularly subsiding [Miyazaki, 1990]. Using JERS1's InSAR data, Furuya~[2004] also confirmed this. Was the localized subsidence before 2000 a precursor for the caldera collapse? We will argue that this is probably not the case. After the beginning of the earthquake swarm on 26 June 2000, significant ground displacements were recorded at Miyakejima both in the permanent GPS stations [e.g., Nishimura et al. 2001] and tiltmeters by the NIED [Ukawa et al. 2001]. Using both FG5 absolute gravimeter and LaCoste-Romberg G-type gravimeters, high precision gravity survey has been repeatedly carried out by ERI, University of Tokyo. Furuya et al~[2003a] showed spatial-temporal gravity changes from the beginning stage to early 2001. Notably, they detected a gravity decrease of as much as 145 μgals (1 μgal=10^{-8} m/s2) at the summit area 2 days prior to the collapse, and interpreted as reflecting the formation of a large void beneath the volcano. Correcting for the effect of topography change due to the collapse, subsequent gravity change data suggested an effective density decrease until the middle August 2000, followed by a significant density increase toward at least November 2000. Those spatial and temporal gravity changes were associated with the explosive

  8. 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

  9. 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

  10. Field-based density measurements as tool to identify preeruption dome structure: set-up and first results from Unzen volcano, Japan

    NASA Astrophysics Data System (ADS)

    Kueppers, Ulrich; Scheu, Bettina; Spieler, Oliver; Dingwell, Donald B.

    2005-03-01

    For an improvement in the quality of conduit flow and dome-related explosive eruption models, knowledge of the preeruption or precollapse density of the rocks involved is necessary. As close investigation is impossible during eruption, the best substitute comes from quantitative investigation of the eruption deposits. The porosity of volcanic rocks is of primary importance for the eruptive behaviour and, accordingly, a key-parameter for realistic models of dome stability and conduit flow. Fortunately, this physical property may be accurately determined via density measurements. We developed a robust, battery-powered device for rapid and reliable density measurements of dry rock samples in the field. The density of the samples (sealed in plastic bags at 250 mbar) is determined using the Archimedean principle. We have tested the device on the deposits of the 1990-1995 eruption of Unzen volcano, Japan. Short setup and operation times allow up to 60 measurements per day under fieldwork conditions. The rapid accumulation of correspondingly large data sets has allowed us to acquire the first statistically significant data set of clast density distribution in block-and-ash flow deposits. More than 1100 samples with a total weight of 2.2 tons were measured. The data set demonstrates that the deposits of the last eruptive episode at Unzen display a bimodal density distribution, with peaks at 2.0±0.1 and 2.3±0.1 g/cm 3, corresponding to open porosity values of 20 and 8 vol.%, respectively. We use this data set to link the results of laboratory-based fragmentation experiments to field studies at recently active lava domes.

  11. Non-Newtonian behavior of plagioclase-bearing basaltic magma: Subliquidus viscosity measurement of the 1707 basalt of Fuji volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ishibashi, Hidemi

    2009-03-01

    Laboratory measurements of viscosity were done for basalt erupted in 1707 AD from Fuji volcano, Japan, using a concentric cylinder rotational viscometer at temperatures of 1297-1157 °C, 1 atm pressure, and fO 2 near the Ni-NiO buffer. On cooling, elongated plagioclase crystals with a mean length/width ratio of ca. 8.5 appeared at 1237 °C, followed by olivine at 1157 °C. At progressively lower temperatures, the total crystal volume fraction increased monotonously to ca. 0.25; viscosity increased from 38.9 to 765 Pa s at a shear strain rate of 1 s - 1 . This basalt magma behaves as a Newtonian fluid at temperatures greater than 1217 °C, but shear-thinning behavior occurs at temperatures less than 1197 °C because of the suspended plagioclase crystals. This behavior is well approximated as a power law fluid. At the onset of shear thinning, the crystal volume fraction was between 0.06 and 0.13, which is attributed to the pronounced lath-shape of plagioclase crystals. The relative viscosity increases monotonously with increase of crystal volume fraction at a constant shear strain rate, and with decrease of shear strain rate at a constant crystal volume fraction. A modified form of the Krieger-Dougherty equation is introduced herein. It enables us to describe the dependencies of relative viscosity on both the crystal volume fraction and shear strain rate, and consequently the onset of shear-thinning behavior.

  12. Source mechanism of long-period events at Kusatsu-Shirane Volcano, Japan, inferred from waveform inversion of the effective excitation functions

    USGS Publications Warehouse

    Nakano, M.; Kumagai, H.; Chouet, B.A.

    2003-01-01

    We investigate the source mechanism of long-period (LP) events observed at Kusatsu-Shirane Volcano, Japan, based on waveform inversions of their effective excitation functions. The effective excitation function, which represents the apparent excitation observed at individual receivers, is estimated by applying an autoregressive filter to the LP waveform. Assuming a point source, we apply this method to seven LP events the waveforms of which are characterized by simple decaying and nearly monochromatic oscillations with frequency in the range 1-3 Hz. The results of the waveform inversions show dominant volumetric change components accompanied by single force components, common to all the events analyzed, and suggesting a repeated activation of a sub-horizontal crack located 300 m beneath the summit crater lakes. Based on these results, we propose a model of the source process of LP seismicity, in which a gradual buildup of steam pressure in a hydrothermal crack in response to magmatic heat causes repeated discharges of steam from the crack. The rapid discharge of fluid causes the collapse of the fluid-filled crack and excites acoustic oscillations of the crack, which produce the characteristic waveforms observed in the LP events. The presence of a single force synchronous with the collapse of the crack is interpreted as the release of gravitational energy that occurs as the slug of steam ejected from the crack ascends toward the surface and is replaced by cooler water flowing downward in a fluid-filled conduit linking the crack and the base of the crater lake. ?? 2003 Elsevier Science B.V. All rights reserved.

  13. Reconstruction of a phreatic eruption on 27 September 2014 at Ontake volcano, central Japan, based on proximal pyroclastic density current and fallout deposits

    NASA Astrophysics Data System (ADS)

    Maeno, Fukashi; Nakada, Setsuya; Oikawa, Teruki; Yoshimoto, Mitsuhiro; Komori, Jiro; Ishizuka, Yoshihiro; Takeshita, Yoshihiro; Shimano, Taketo; Kaneko, Takayuki; Nagai, Masashi

    2016-05-01

    The phreatic eruption at Ontake volcano on 27 September 2014, which caused the worst volcanic disaster in the past half-century in Japan, was reconstructed based on observations of the proximal pyroclastic density current (PDC) and fallout deposits. Witness observations were also used to clarify the eruption process. The deposits are divided into three major depositional units (Units A, B, and C) which are characterized by massive, extremely poorly sorted, and multimodal grain-size distribution with 30-50 wt% of fine ash (silt-clay component). The depositional condition was initially dry but eventually changed to wet. Unit A originated from gravity-driven turbulent PDCs in the relatively dry, vent-opening phase. Unit B was then produced mainly by fallout from a vigorous moist plume during vent development. Unit C was derived from wet ash fall in the declining stage. Ballistic ejecta continuously occurred during vent opening and development. As observed in the finest population of the grain-size distribution, aggregate particles were formed throughout the eruption, and the effect of water in the plume on the aggregation increased with time and distance. Based on the deposit thickness, duration, and grain-size data, and by applying a scaling analysis using a depth-averaged model of turbulent gravity currents, the particle concentration and initial flow speed of the PDC at the summit area were estimated as 2 × 10-4-2 × 10-3 and 24-28 m/s, respectively. The tephra thinning trend in the proximal area shows a steeper slope than in similar-sized magmatic eruptions, indicating a large tephra volume deposited over a short distance owing to the wet dispersal conditions. The Ontake eruption provided an opportunity to examine the deposits from a phreatic eruption with a complex eruption sequence that reflects the effect of external water on the eruption dynamics.

  14. Imaging the hydrothermal system beneath the Jigokudani valley, Tateyama volcano, Japan: implications for structures controlling repeated phreatic eruptions from an audio-frequency magnetotelluric survey

    NASA Astrophysics Data System (ADS)

    Seki, Kaori; Kanda, Wataru; Ogawa, Yasuo; Tanbo, Toshiya; Kobayashi, Tomokazu; Hino, Yuta; Hase, Hideaki

    2015-01-01

    This study focuses on the results of an audio-frequency magnetotelluric (AMT) survey across the Jigokudani valley, Tateyama volcano, Japan, to investigate the spatial relationship between the distribution of electrical resistivity and geothermal activity and to elucidate the geologic controls on both its phreatic eruption history and recent increase in phreatic activity. The AMT data were collected at eight locations across the Jigokudani valley in September 2013, with high quality data obtained from most sites, enabling the identification of an underground 2D resistivity structure from the transverse magnetic (TM) mode data. The data obtained during this study provided evidence of a large conductive region beneath the surface of the Jigokudani valley that is underlain by a resistive layer at depths below 500 m. The resistive layer is cut by a relatively conductive region that extends subvertically toward the shallow conductor. The shallow conductive region is divided into an uppermost slightly conductive section that is thought to be a lacustrine sediment layer of an extinct crater lake containing hydrothermal fluids and a lower section containing a mix of volcanic gases and hydrothermal fluids. The low permeability of the clay zone means that the uppermost clayey sediments allow the accumulation of gases in the lower section of the conductive region, suggesting the existence of a cap structure. The deep resistive layer likely consists of units similar to the granitic rocks that are widely exposed throughout the Jigokudani valley. We suggest that the relatively conductive zone that separates these granitic rocks represents a high-temperature volcanic gas conduit, given that the most active fumarole in the Jigokudani valley lies directly along the trajectory of this path.

  15. Implications of ASOS winds on regulatory dispersion modeling applications

    SciTech Connect

    Jones, W.B.; Brower, R.P.

    1998-12-31

    With the advent of the Automated Surface Observing System (ASOS) throughout the United States during the 1990`s, an unprecedented level of meteorological data is now available. For the first time, observations of standard meteorological variables are available on a minute-by-minute basis. As a result, ASOS has tremendously increased the real-time data available for both weather forecasting and aviation purposes. However, the affect of the ASOS method of data collection on the dispersion modeling community is less clear. Because the hourly data now being reported at most stations across the country are being gathered in a fundamentally different way than previously, it is prudent to examine the differences between hourly meteorological observations gathered before and after ASOS. This paper scrutinizes wind speed and direction data gathered at Baltimore-Washington International Airport and Washington Dulles International Airport and quantifies the differences. Wind data are critical in determining the transport and dispersion of pollutant plumes. Relationships between manually gathered wind data and ASOS wind data are examined. Finally, potential ramifications on dispersion modeling applications are discussed.

  16. Radar Image, Hokkaido, Japan

    NASA Image and Video Library

    2000-05-18

    The southeast part of the island of Hokkaido, Japan, is an area dominated by volcanoes and volcanic caldera. The active Usu Volcano is at the lower right edge of the circular Lake Toya-Ko and near the center of the image.

  17. Time Variation of Seismic Anisotropy, Stress and Cracks on Active Volcanoes (Invited)

    NASA Astrophysics Data System (ADS)

    Savage, M. K.

    2013-12-01

    We summarize measurements of seismic anisotropy and its relation to other geophysical measurements of stress and cracks on eleven active volcanoes; Unzen (Unz), Sakurajima (Sak), Aso, Asama (Asm) and Kirishima (Kir) in Japan; Okmok (Okm) in Alaska, Ruapehu (Rua) and Tongariro (Ton) in New Zealand, Soufriere Hills (Sou) in Montserrat, Kilauea (Kil) in Hawaii and Piton de la Fournaise (PdF) in La Reunion. We used the MFAST shear wave splitting computer code, an objective code that is fully automatic except for the S arrival pick. Fast polarization directions (phi) should be parallel to cracks and hence the maximum horizontal stress direction. Time delays (dt) increase with path length and percent anisotropy, usually related to crack density. Where possible we used S waves from deep earthquakes to ensure that the movement of the earthquakes was not correlated with the volcanic activity. At some volcanoes we used families of repeating events with similar waveforms and at most volcanoes we also computed splitting at earthquakes local to the volcano. We compared the phi and dt variation in time to eruption occurrences and to other available parameters including seismicity rate, b-values, focal mechanisms, isotropic velocity changes from noise cross-correlation, Vp/Vs ratios, Geodetic measurements such as GPS and tilt, and gas flux. All volcanoes had some stations with excellent shear wave arrivals that yielded measureable splitting. Individual measurements showed scatter in most areas, but at most of the volcanoes, moving averages of phi or dt (or both) yielded time variations that correlated with other measurements related to volcanic activity or to stress changes or changes in crack-filling material such as gas flux. The multiplet studies did not yield slowly varying splitting but instead showed distinct jumps in splitting parameters at various times, which appears to be caused in part by cycle skipping. Time resolution of changes depends on the seismicity available

  18. The Role of Philippine Sea Plate to the Genesis of Quaternary Magmas of Northern Kyushu Island, Japan, Inferred from Along-Arc Geochemical Variations

    NASA Astrophysics Data System (ADS)

    Shibata, T.; Yoshikawa, M.; Itoh, J.; Ujike, O.; Miyoshi, M.; Takemura, K.

    2013-12-01

    Quaternary volcanoes on Kyushu Island comprise volcanoes Himeshima, Futagoyama, Yufu-Tsurumi, Kuju, Aso, Kirishima and Sakurajima from north to south alongstrike the volcanic front. Adakitic lavas are observed from Yufu-Tsurumi and Kuju volcanoes in northern Kyushu (Kita et al., 2001; Sugimoto et al., 2007), whereas no Quaternary adakites were observed at Aso (e.g., Hunter, 1998) and the volcanoes south of Aso along the entire Ryukyu arc. Sugimoto et al. (2007) suggested that the trace element and Sr, Nd, and Pb isotopic compositions of adakitic magmas from Yufu-Tsurumi volcano indicate derivation of the magmas by partial melting of the subducting PSP. In contrast, Zellmer et al. (2012) suggested that these adakites may have formed by fractional crystallization of mantle-derived mafic magmas within the garnet stability field in the crust. The Honshu-Kyushu arc transition is a particular favorable setting to address these controversial models for the origin of the adakitic lavas, because of the potential relationship between the PSP materials and the alongstrike variation of the lava chemistry. The Palau-Kyushu ridge divides the oceanic crust of the PSP into northeastern and southwestern segments with ages of 26-15 (Shikoku Basin) and 60-40 Ma (West Philippine Basin), respectively (Mahony et al., 2011). Although there are no clear plate images beneath northern Kyushu, the northern extension of the Palau-Kyushu ridge potentially corresponds to the boundary between the SW Japan and Ryukyu arcs. If adakite genesis was related to the subducted slab rather than the overlying crust, then the spatial distribution of Quaternary adakites should correlate with the age of the subducted PSP. In order to test such correlation and elucidate the petrogenesis of the northern Kyushu adakites, we compiled major and trace elements and Sr-Nd-Pb isotope ratios from volcanoes along the arc front that includes the transition from adakitic to non-adakitic arc volcanism. Comprehensive

  19. Crustal magma pathway beneath Aso caldera inferred from three-dimensional electrical resistivity structure

    NASA Astrophysics Data System (ADS)

    Hata, Maki; Takakura, Shinichi; Matsushima, Nobuo; Hashimoto, Takeshi; Utsugi, Mitsuru

    2016-10-01

    At Naka-dake cone, Aso caldera, Japan, volcanic activity is raised cyclically, an example of which was a phreatomagmatic eruption in September 2015. Using a three-dimensional model of electrical resistivity, we identify a magma pathway from a series of northward dipping conductive anomalies in the upper crust beneath the caldera. Our resistivity model was created from magnetotelluric measurements conducted in November-December 2015; thus, it provides the latest information about magma reservoir geometry beneath the caldera. The center of the conductive anomalies shifts from the north of Naka-dake at depths >10 km toward Naka-dake, along with a decrease in anomaly depths. The melt fraction is estimated at 13-15% at 2 km depth. Moreover, these anomalies are spatially correlated with the locations of earthquake clusters, which are distributed within resistive blocks on the conductive anomalies in the northwest of Naka-dake but distributed at the resistive sides of resistivity boundaries in the northeast.

  20. 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 ...

  1. 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

  2. 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 ...

  3. The evaluation of ASOS for the Kennedy Space Center's Shuttle Landing Facility

    NASA Technical Reports Server (NTRS)

    Yersavich, Ann; Wheeler, Mark; Taylor, Gregory; Schumann, Robin; Manobianco, John

    1994-01-01

    This report documents the Applied Meteorology Unit's (AMU) evaluation of the effectiveness and utility of the Automated Surface Observing System (ASOS) in terms of spaceflight operations and user requirements. In particular, the evaluation determines which of the Shuttle Landing Facility (SLF) observation requirements can be satisfied by ASOS. This report also includes a summary of ASOS' background, current configuration and specifications, system performance, and the possible concepts of operations for use of ASOS at the SLF. This evaluation stems from a desire by the Air Force to determine if ASOS units could be used to reduce the cost of SLF meteorological observations.

  4. Magma Degassing and Evolution Processes of the 2000 Eruption of Miyakejima Volcano, Japan, Deduced From of Olivine-Hosted Melt Inclusion Analyses

    NASA Astrophysics Data System (ADS)

    Saito, G.; Morishita, Y.

    2008-12-01

    Chemical analyses of melt inclusions in Mg-poor (Mg#68-73) and Mg-rich (Mg#76-84)"@olivines from a bomb and lapilli from the 18 August 2000 eruption of Miyakejima volcano, Japan, were carried out in order to investigate degassing and evolution process "Íf the magma. Analyses of major elements, S and Cl of the melt inclusions were made by EPMA, and H2O and CO2 by FTIR and SIMS (Miyagi et al., 1995; Hauri et al., 2002). Major element composition of Mg-poor olivine-hosted melt inclusions (Mg-poor Ol MIs) is similar to that of groundmass in the bomb, indicating the melt entrapment just before the eruption. The Mg-poor Ol MIs have volatile contents of 0.7-2.5 wt.% H2O, 0.005-0.02 wt.% CO2, 0.05-0.17 wt. % S, and 0.06-0.1 wt. % Cl, that are roughly similar to those of plagioclase-hosted melt inclusions (Saito et al., 2005). Gas saturation pressure of the magma is calculated to be 20-100 MPa on the basis of the H2O and CO2 contents of Mg-poor Ol MIs, corresponds to the depth of 1-4 km. On the other hand, the Mg-rich olivine-hosted melt inclusions (Mg-rich Ol MIs) have SiO2 and K2O-poor but Al2O3-rich composition than the whole rock composition of the bomb and lapilli. They have volatile contents of 1.9-3.5 wt.% H2O, 0.003-0.025 wt.% CO2, 0.06-0.21 wt.% S, and 0.04-0.07 wt.% Cl, that are a little higher H2O and S and lower Cl contents than those of Mg-rich Ol MIs. Gas saturation pressure of the magma is calculated to be 50-150 MPa on the basis of the H2O and CO2 contents of Mg-rich Ol MIs. Ratios of H2O and S contents of both the Mg-poor and Mg-rich Ol MIs are similar to that of volcanic gas emitted from the summit after the 2000 eruption, while their ratios of CO2 and H2O contents are lower than that of volcanic gas. Existence of the Al2O3-rich less-evolved melt with high H2O content is consistent with the petrological and experimental studies that low-MgO high-alumina basalt is derived from primary magma with high H2O content (Uto, 1986; Sisson and Grove, 1993). The

  5. Melt inclusion record of CO2 and H2O evolution of magma from Kikai-Akahoya caldera-forming eruption of Satsuma-Iojima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Saito, G.; Morishita, Y.; Kawanabe, Y.

    2009-12-01

    Geological survey and chemical analyses of pyroclastic rocks and melt inclusions in the deposits of Kikai-Akahoya caldera-forming eruption (7.3 ka) of Satsuma-Iojima volcano, Japan, were carried out in order to investigate compositional variation and degassing process οf the magma. Three pyroclastic units were erupted by the eruption successively; Koya-Funakura air-fall pumice (KFA), densely welded Funakura pyroclastic flow deposit and nonwelded Takeshima pyroclastic flow deposit (TPF; Ono et al., 1982). The total mass of the tephra is estimated to be more than 100 km3 (Machida and Arai, 2003). The KFA is a layer of coarse-grained rhyolitic pumice deposit (SiO2=71-72 wt.%) with 2-3m thick. The TPF has a thickness of about 30m and can be divided into at least three units. The deposit mainly consists of rhyolitic pumice (SiO2=70-72 wt.%) and vitric ash with small amount of andesitic scoria (SiO2=58-60 wt.%) and banded pumice. The upper unit is more rich in andesitic scoria than the lower unit. Analyses of major elements and S of the melt inclusions (MIs) in plagioclases and pyroxenes in the pumice and scoria were made by EPMA, and H2O and CO2 by SIMS. Major element composition of MIs in the pumice and scoria is similar to that of groundmass of them, respectively, indicating the melt entrapment just before the eruption. The MIs in the KFA have volatile contents of 4-6 wt.% H2O, <0.007 wt.% CO2 and <0.01 wt.% S. Gas saturation pressure of the magma is calculated to be 100-260 MPa on the basis of the H2O and CO2 contents of the MIs. On the other hand, the MIs in the rhyolitic pumice in the lower TPF have similar H2O and S contents but higher CO2 content (0.01-0.03 wt.%) than those of the KFA. Gas saturation pressure of the magma is calculated to be 130-270 MPa. The MIs in the andesitic scoria in the upper TPF have higher S (0.05-0.12 wt.%), similar CO2 content and lower H2O (2-3 wt.%) contents than those of the lower unit. Gas saturation pressure of the magma is

  6. Mt. Fuji, Honshu, Japan

    NASA Image and Video Library

    1981-10-14

    STS002-09-390 (12-14 Nov. 1981) --- Honshu Island, Japan, and its snow-covered Fuji-San or Fuji-Yama volcano are the features of this 70mm frame. The volcano peak is 12,400 feet tall. The western suburbs of Tokyo are at right edge of the photograph. Isu Peninsula is at the bottom, separating the Suruga and Sagami Bay. Other large cities include Yokohama, Kozu, Shizuoka, Namazu and Odawara. Photo credit: NASA

  7. Geomorphology and sedimentary features, and temporal component-change of lahar deposits at the northern foot of Chokai volcano, NE Japan

    NASA Astrophysics Data System (ADS)

    Minami, Y.; Ohba, T.; Kataoka, K.; Hayashi, S.

    2014-12-01

    Chokai volcano is an andesitic stratovolcano that collapsed to the north ca.2500 years ago. The post-collapse fan deposits are distributed in the northern foot of the volcano, and to reveal their depositional process in terms of modern sedimentology, we carried out the geological study includung digging survey, as well as geomorphological analysis, mineralogy, and 14C chronology. Consequently, the geological study revealed that the fan deposits consist of more than 16 units, which are debris flow, hyperconcentrated flow and streamflow deposits. We give hare general name lahar deposits for these deposits. The lahar deposits have a total thickness of 30 m, and overlie the 2.5-ka Kisakata debris avalanche deposit. The lahar deposits form a part of volcanic fan and volcaniclastic apron of Chokai volcano. In proximal areas (steep or moderate sloped areas), the lahar flowed down as debris flows, and in the distal area (horizontal area) the lahars transformed into hyperconcentrated flow or stream flows but partly arrived the area as debris flow. The hyperconcentrated flows or stream flows reached the horizontal area at least four times, supposed by AMS dating (the ages of some lahar deposits are 2200, 1500-1600, 1000-1200, and 100-200 yBP). The lahar deposits contain clasts of altered andesite, fresh andesite, mudstone and sandstone. Proportions of altered andesite clasts to total clasts decrease upwards in stratigraphic sequence. Matrices of the lower eight units are composed of grayish-blue clay, and are different from those of the upper eight units, composed of brownish yellow volcanic sand. The stratigraphic variation in matrix component is consistent with the change in matrix mineral assemblage, possibly reflecting changes in the source materials from Chokai volcano.

  8. Civil UAV Applications in Japan and Related Safety & Certification

    DTIC Science & Technology

    2007-11-02

    Background and Development of Autonomous Helicopter Japan is famous for volcanoes and earthquakes. In 1990 - Unzen volcano erupted. In 1995 - the...Payload up to 100kg • Operational range < 250m • Operational altitude < 50m RPH 2-Agricultural Spraying • In Service for Volcano Observing by...Rotor Diameter 4.8m Applications of Autonomous YAMAHA Unmanned Helicopter Observation of Volcanoes April 2000 at Erupting Volcanoes Mt.Usu (The

  9. 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.

  10. Dante's volcano

    NASA Astrophysics Data System (ADS)

    1994-09-01

    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.

  11. Volcano Infrasound

    NASA Astrophysics Data System (ADS)

    Johnson, J. B.; Fee, D.; Matoza, R. S.

    2013-12-01

    Open-vent volcanoes generate prodigious low frequency sound waves that tend to peak in the infrasound (<20 Hz) band. These long wavelength (> ~20 m) atmospheric pressure waves often propagate long distances with low intrinsic attenuation and can be well recorded with a variety of low frequency sensitive microphones. Infrasound records may be used to remotely monitor eruptions, identify active vents or track gravity-driven flows, and/or characterize source processes. Such studies provide information vital for both scientific study and volcano monitoring efforts. This presentation proposes to summarize and standardize some of the terminology used in the still young, yet rapidly growing field of volcano infrasound. Herein we suggest classification of typical infrasound waveform types, which include bimodal pulses, blast (or N-) waves, and a variety of infrasonic tremors (including broadband, harmonic, and monotonic signals). We summarize various metrics, including reduced pressure, intensity, power, and energy, in which infrasound excess pressures are often quantified. We also describe the spectrum of source types and radiation patterns, which are typically responsible for recorded infrasound. Finally we summarize the variety of propagation paths that are common for volcano infrasound radiating to local (<10 km), regional (out to several hundred kilometers), and global distances. The effort to establish common terminology requires community feedback, but is now timely as volcano infrasound studies proliferate and infrasound becomes a standard component of volcano monitoring.

  12. Fluid-fluxed melting of mantle versus decompression melting of hydrous mantle plume as the cause of intraplate magmatism over a stagnant slab: Implications from Fukue Volcano Group, SW Japan

    NASA Astrophysics Data System (ADS)

    Kuritani, Takeshi; Sakuyama, Tetsuya; Kamada, Natsumi; Yokoyama, Tetsuya; Nakagawa, Mitsuhiro

    2017-06-01

    The Pacific Plate subducting from the Japan Trench has accumulated in the mantle transition zone beneath NE Asia, and intraplate magmatism has been active above the stagnant Pacific slab. To understand the origin of the intraplate magmatism in relation to slab stagnation, a petrological and geochemical study was carried out on basaltic samples from a monogenetic volcano of the Fukue Volcano Group, southwest Japan. The eruption products consist of low-Si and high-Si groups, and the two magmas are hypothesized to originate from different mantle source material based on radiogenic isotopic compositions. The H2O contents of the primary magmas were estimated as 2 wt.% for both the low-Si and high-Si groups. Analyses using multicomponent thermodynamics suggested that the low-Si and high-Si primary magmas were generated at 2.5 GPa and 1345 °C and at 1.8 GPa and 1285 °C, respectively. These results, and the geochemical characteristics of the products, indicated that the low-Si magma was generated in the asthenospheric mantle whereas the high-Si magma was produced by interaction of the low-Si magma with the sub-continental lithospheric mantle. The low mantle potential temperature of 1300 °C and hydrous nature (H2O/Ce = 650) of the low-Si magma suggested that the magma was generated by fluid-fluxed melting of the asthenospheric mantle. Based on these results and those obtained in previous studies, intraplate magmatism over the stagnant Pacific slab can be summarized as having been caused by either melting of the asthenospheric mantle through an influx of fluids derived from the mantle transition zone or decompression melting of a hydrous mantle plume derived from the mantle transition zone. We infer that the fluids for the flux melting have been released from the mantle transition zone where water was locally saturated. Meanwhile, hydrous mantle plumes have been generated at the mantle transition zone where a return flow of sub-lithospheric mantle material entrained

  13. Motivations for muon radiography of active volcanoes

    NASA Astrophysics Data System (ADS)

    Macedonio, G.; Martini, M.

    2010-02-01

    Muon radiography represents an innovative tool for investigating the interior of active volcanoes. This method integrates the conventional geophysical techniques and provides an independent way to estimate the density of the volcano structure and reveal the presence of magma conduits. The experience from the pioneer experiments performed at Mt. Asama, Mt. West Iwate, and Showa-Shinzan (Japan) are very encouraging. Muon radiography could be applied, in principle, at any stratovolcano. Here we focus our attention on Vesuvius and Stromboli (Italy).

  14. Syrian Volcano

    NASA Technical Reports Server (NTRS)

    2006-01-01

    23 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (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. The light-toned streaks that cross the scene were formed by passing dust devils, a common occurrence in Syria.

    Location near: 13.0oS, 102.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

  15. Syrian Volcano

    NASA Technical Reports Server (NTRS)

    2006-01-01

    23 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (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. The light-toned streaks that cross the scene were formed by passing dust devils, a common occurrence in Syria.

    Location near: 13.0oS, 102.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

  16. Chilean Volcanoes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On the border between Chile and the Catamarca province of Argentina lies a vast field of currently dormant volcanoes. Over time, these volcanoes have laid down a crust of magma roughly 2 miles (3.5 km) thick. It is tinged with a patina of various colors that can indicate both the age and mineral content of the original lava flows. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on May 15, 1999. This is a false-color composite image made using shortwave infrared, infrared, and green wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  17. Mineralogical study on volcanic ash of the eruption on September 27, 2014 at Ontake volcano, central Japan: correlation with porphyry copper systems

    NASA Astrophysics Data System (ADS)

    Minami, Yusuke; Imura, Takumi; Hayashi, Shintaro; Ohba, Tsukasa

    2016-04-01

    The volcanic ash of the eruption on September 27, 2014 at Ontake volcano consists mostly of altered rock fragments. The ash contains partly altered volcanic rock fragments consisting of primary igneous minerals (plagioclase, orthopyroxene, titanomagnetite, and feldspars) and volcanic glass accompanied by alteration minerals to some extents, and contains no juvenile fragments. These features indicate that the eruption was a non-juvenile hydrothermal eruption that was derived from the hydrothermal system developed under the crater. The major minerals derived from hydrothermal alteration zones are silica mineral, kaolin-group mineral, smectite, pyrophyllite, muscovite, alunite, anhydrite, gypsum, pyrite, K-feldspar, albite, and rutile. Minor chlorite, biotite, and garnet are accompanied. Five types of alteration mineral associations are identified from observations on individual ash particles: silica-pyrite, silica-pyrite ± alunite ± kaolin, silica-pyrophyllite-pyrite, silica-muscovite ± chlorite, and silica-K-feldspar ± albite ± garnet ± biotite. The associations indicate development of advanced argillic, sericite, and potassic alteration zones under the crater. Occurrence of anhydrite veinlet and the set of alteration zones indicate hydrothermal alteration zones similar to late-stage porphyry copper systems. Comparing the mineral associations with the geologic model of the late-stage porphyry copper systems, the source depths of mineral associations are estimated to range from near surface to >2 km. The depths of advanced argillic alteration, sericite, and potassic zones are 0 to ~2, ~1.5 to ~2, and >2 km, respectively.

  18. Source spectrum and source time function of volcanic tremor determined with a dense seismic network near the summit crater of Izu-Oshima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Oikawa, Jun; Ida, Yoshiaki; Yamaoka, Koshun

    1994-05-01

    Digital seismic records of episodic volcanic tremor, obtained with a dense seismic network near the summit crater of Izu-Oshima volcano, were analyzed to determine source spectrum and source time function. Source spectrum and transfer function could be separated because the seismic records showed a systematic change with distance from the source. The source spectrum of velocity amplitude had a different frequency, f, dependence above and below a corner frequency of 8 to 10 Hz. At high ranges, the spectrum was proportional to f(exp -2), while at low ranges, it was proportional to f(exp 2). Inversion of this frequency-dependent source spectrum yields a source time function that can be represented by an impulse that attenuates in about 0.1 s. Repeated impulses could explain observed volcanic tremor that persists for many minutes or longer and that have complicated phase spectra. The source spectrum gives an energy release rate of about 5.2 x 10(exp 2) J/s, so that the total energy released is about 1.0 x 10(exp 5) J during a tremor episode of about 3 min at Izu-Oshima. Such energy release is comparable to the seismic energy released by an earthquake of magnitude 0.1.

  19. Temporal evolution of a hydrothermal system in Kusatsu-Shirane Volcano, Japan, inferred from the complex frequencies of long-period events

    USGS Publications Warehouse

    Kumagai, H.; Chouet, B.A.; Nakano, M.

    2002-01-01

    We present a detailed description of temporal variations in the complex frequencies of long-period (LP) events observed at Kusatsu-Shirane Volcano. Using the Sompi method, we analyze 35 LP events that occurred during the period from August 1992 through January 1993. The observed temporal variations in the complex frequencies can be divided into three periods. During the first period the dominant frequency rapidly decreases from 5 to 1 Hz, and Q of the dominant spectral peak remains roughly constant with an average value near 100. During the second period the dominant frequency gradually increases up to 3 Hz, and Q gradually decreases from 160 to 30. During the third period the dominant frequency increases more rapidly from 3 to 5 Hz, and Q shows an abrupt increase at the beginning of this period and then remains roughly constant with an average value near 100. Such temporal variations can be consistently explained by the dynamic response of a hydrothermal crack to a magmatic heat pulse. During the first period, crack growth occurs in response to the overall pressure increase in the hydrothermal system caused by the heat pulse. Once crack formation is complete, heat gradually changes the fluid in the crack from a wet misty gas to a dry gas during the second period. As heating of the hydrothermal system gradually subsides, the overall pressure in this system starts to decrease, causing the collapse of the crack during the third period.

  20. 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.

  1. 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

  2. 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.

  3. 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 ...

  4. Detection of microwave emission due to rock fracture as a new tool for geophysics: A field test at a volcano in Miyake Island, Japan

    NASA Astrophysics Data System (ADS)

    Takano, Tadashi; Maeda, Takashi; Miki, Yoji; Akatsuka, Sayo; Hattori, Katsumi; Nishihashi, Masahide; Kaida, Daishi; Hirano, Takuya

    2013-07-01

    This paper describes a field test to verify a newly discovered phenomenon of microwave emission due to rock fracture in a volcano. The field test was carried out on Miyake Island, 150 km south of Tokyo. The main objective of the test was to investigate the applicability of the phenomenon to the study of geophysics, volcanology, and seismology by extending observations of this phenomenological occurrence from the laboratory to the natural field. We installed measuring systems for 300 MHz, 2 GHz, and 18 GHz-bands on the mountain top and mountain foot in order to discriminate local events from regional and global events. The systems include deliberate data subsystems that store slowly sampled data in the long term, and fast sampled data when triggered. We successfully obtained data from January to February 2008. During this period, characteristic microwave pulses were intermittently detected at 300 MHz. Two photographs taken before and after this period revealed that a considerably large-scale collapse occurred on the crater cliff. Moreover, seismograms obtained by nearby observatories strongly suggest that the crater subsidence occurred simultaneously with microwave signals on the same day during the observation period. For confirmation of the microwave emission caused by rock fracture, these microwave signals must be clearly discriminated from noise, interferences, and other disturbances. We carefully discriminated the microwave data taken at the mountaintop and foot, checked the lightning strike data around the island, and consequently concluded that these microwave signals could not be attributed to lightning. Artificial interferences were discriminated by the nature of their waveforms. Thus, we inferred that the signals detected at 300 MHz were due to rock fractures during cliff collapses. This result may provide a useful new tool for geoscientists and for the mitigation of natural hazards.

  5. Crustal deformation model of the Beppu-Shimabara graben area, central Kyushu, Japan, based on inversion of three-component GNSS data in 2000-2010

    NASA Astrophysics Data System (ADS)

    Mochizuki, Kazuma; Mitsui, Yuta

    2016-11-01

    The 2016 Kumamoto earthquakes, including an Mw-7 right-lateral earthquake on April 15 (UTC), occurred along faults within the Beppu-Shimabara graben in central Kyushu, Japan. Previous studies showed that the graben area was under heterogeneous stress conditions with north-south T-axes and spreading in a north-south direction. Here, we construct a detailed crustal deformation model using three-component Global Navigation Satellite System data in 2000-2010 and considering the distribution of geological fault traces in this area. Our inversion analysis suggests that the strain accumulation rate for the right-lateral seismic slip segment (corresponding to the Futagawa fault), where the largest of the 2016 Kumamoto earthquakes ruptured, was several times smaller than the other segments in the Beppu-Shimabara graben. Furthermore, we observe distinct subsidence along the Beppu-Shimabara graben. Our base model attributes the subsidence to deflation of magma reservoirs beneath volcanoes, but the observed vertical velocities are poorly fit. In order to improve the fitting results for the vertical deformation, we need more sophisticated volcano-deformation model (such as a sill-like deformation source for Mt. Aso) or graben model. [Figure not available: see fulltext.

  6. Marine Geography of the Sea of Japan

    DTIC Science & Technology

    1951-01-01

    coast line. In general, the volcanoes that still con be identified in Japan ore not older than the Pleistocene or Glacic; epoch (1 million years...Oe ee nuneros volcanoes and frequent ethquokes. Reoevences: RESTRICTED Many submarine canyons are present on the continental shelf, but due to the... volcanoes and frequent earthquakes. References: Balzak, S. S., V. F. Vasyutin, and Y. G. Feigin, "Economic Geography of the USSR," The Macmillion Company

  7. Effect of syneruptive decompression path on shifting intensity in basaltic sub-Plinian eruption: Implication of microlites in Yufune-2 scoria from Fuji volcano, Japan

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuki; Fujii, Toshitsugu

    2010-12-01

    To constrain the timing and conditions of syneruptive magma ascent that are responsible for shifting eruption intensity, we have investigated a basaltic sub-Plinian eruption that produced Yufune-2 scoria in Fuji volcano 2200 years ago. We deduced magmatic decompression conditions from groundmass microlite textures, including decompression path (i.e. evolution in decompression rate) and approximate decompression rate, in order to relate them to eruption intensity. The microlites revealed decompression conditions after water saturation at 700-1100 m depth. The temporal change in scoria size indicates that the magma discharge rate and resultant eruption intensity increased from unit a to unit b, and then declined toward ending units d and e. The overall decompression rate in each eruptive unit has a positive correlation with eruption intensity. The variation in decompression rate was enlarged in the final units, where the maximum remained the same as the peak through the eruption (0.13-0.22 MPa/s for units b and c), while the minimum was 0.025 MPa/s. The large variation here is due to 1) variation in flow velocity across conduit and 2) part of the erupted magma in unit d experienced remarkably slow decompression (0.002-0.003 MPa/s) resulting from decreased overpressure in the reservoir following the major eruption of unit b. Furthermore, crystal size distribution (CSD) of microlites implied that the earliest erupted magma (unit a) had once been decompressed slowly (0.005-0.012 MPa/s), having been arrested by material in the conduit-vent system, which was followed by an increase in decompression rate due to removal of the material at the initiation of the eruption. In addition, the magma that had been ascending slowly before the unit-d eruption may record the increase in decompression rate. This increased rate resulted from being pushed up by the successive magma at the start of that eruption. Two factors had a major impact on eruption intensity. First, magma

  8. AgNa2Mo3O9AsO4

    PubMed Central

    Hamza, Hamadi; Zid, Mohamed Faouzi; Driss, Ahmed

    2011-01-01

    The title compound, silver disodium trimolybdenum(VI) nonaoxide arsenate, AgNa2Mo3O9AsO4, was prepared by a solid-state reaction at 808 K. The structure consists of an infinite (Mo3AsO13)n ribbon, parallel to the c axis, composed of AsO4 tetra­hedra and MoO6 octa­hedra sharing edges and corners. The Na and Ag ions partially occupy several independent close positions, with various occupancies, in the inter-ribbon space delimited by the one-dimensional framework. The composition was refined to Ag1.06(1)Na1.94(1)Mo3O9AsO4. PMID:22219728

  9. 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.

  10. Magma mixing and degassing processes of 2011 eruption series of Kirishima volcano, Japan, based on chemical analyses of minerals and melt inclusions

    NASA Astrophysics Data System (ADS)

    Saito, G.

    2012-12-01

    Petrological studies of the essential products of phreato-magmatic, sub-Plinian, Vulcanian and minor ash eruptions in 2011 eruption series of Shinmoedake, Kirishima volcanic group, Japan, were carried out. Using the combined geological, petrological and gas emission observations from the 2011 eruptions, I investigated magma ascent and degassing processes of the eruptions. The bimodal plagioclase core composition, relatively small rims of olivines and pyroxenes, and diffusion profiles of the olivines indicate the mixing of mafic magma and felsic magma in several days before the sub-Plinian eruption. Melt inclusion analysis indicated that the end members of the magma mixing were basaltic andesite and dacite magmas and its mixing ratio was estimated to be 0.4 of the basaltic andesite. Magmas of the following Vulcanian and ash eruptions in February to June have similar mode composition, chemical compositions of phenocrysts, groundmass minerals and groundmass and zoning profiles of olivines of the eruptive products of to those of the sub-Plinian eruptions. These results indicate that magma mixing process proposed for the sub-Plinian eruptions also occurred in eruptions showing various styles. These results suggest that the mafic magma input to felsic magma intermittently occurred after the sub-Plinian eruptions to cause the minor eruptions in March to June. The amount of the degassed magma that was estimated based on sulfur content of melt inclusions of the end member magmas and SO2 flux observation was larger than that of eruptive products in 2011, indicating the degassing of the magma in the chamber due to convection of the magma in a conduit.

  11. 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.

  12. Characteristics of the surface ruptures associated with the 2016 Kumamoto earthquake sequence, central Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Shirahama, Yoshiki; Yoshimi, Masayuki; Awata, Yasuo; Maruyama, Tadashi; Azuma, Takashi; Miyashita, Yukari; Mori, Hiroshi; Imanishi, Kazutoshi; Takeda, Naoto; Ochi, Tadafumi; Otsubo, Makoto; Asahina, Daisuke; Miyakawa, Ayumu

    2016-11-01

    The 2016 Kumamoto earthquake sequence started with a M J (Japan Meteorological Agency magnitude) 6.5 event on April 14, and culminated in a M J 7.3 event on April 16. Associated with the sequence, approximately 34-km-long surface ruptures appeared along the eastern part of the Futagawa fault zone and the northernmost part of the Hinagu fault zone. We carried out an urgent field investigation soon after the earthquake to map the extent and displacement of surface ruptures with the following results. (1) The rupture zone generally consisted of a series of left-stepping en echelon arrays of discontinuous fault traces of various lengths. (2) Slip exceeding 100 cm occurred on previously unrecognized fault traces in the alluvial lowland of the Kiyama plain and on the western rim of the Aso volcano caldera. (3) Large slip with maximum dextral slip of 220 cm was measured throughout the central section of the rupture zone along the Futagawa segment, and the slip gradually decreased bilaterally on the adjoining northeastern and southwestern sections. (4) The surface rupture mostly occurred along fault traces mapped in previous active fault investigations. (5) Most of the surface ruptures were produced by the mainshock, and significant postseismic slip occurred after the mainshock.[Figure not available: see fulltext.

  13. Soufriere Hills Volcano

    NASA Technical Reports Server (NTRS)

    2002-01-01

    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.

    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 Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is

  14. Mud Volcanoes Formation And Occurrence

    NASA Astrophysics Data System (ADS)

    Guliyev, I. S.

    2007-12-01

    Mud volcanoes are natural phenomena, which occur throughout the globe. They are found at a greater or lesser scale in Azerbaijan, Turkmenistan, Georgia, on the Kerch and Taman peninsulas, on Sakhalin Island, in West Kuban, Italy, Romania, Iran, Pakistan, India, Burma, China, Japan, Indonesia, Malaysia, New Zealand, Mexico, Colombia, Trinidad and Tobago, Venezuela and Ecuador. Mud volcanoes are most well-developed in Eastern Azerbaijan, where more than 30% of all the volcanoes in the world are concentrated. More than 300 mud volcanoes have already been recognized here onshore or offshore, 220 of which lie within an area of 16,000 km2. Many of these mud volcanoes are particularly large (up to 400 m high). The volcanoes of the South Caspian form permanent or temporary islands, and numerous submarine banks. Many hypotheses have been developed regarding the origin of mud volcanoes. Some of those hypotheses will be examined in the present paper. Model of spontaneous excitation-decompaction (proposed by Ivanov and Guliev, 1988, 2002). It is supposed that one of major factors of the movement of sedimentary masses and formation of hydrocarbon deposits are phase transitions in sedimentary basin. At phase transitions there are abnormal changes of physical and chemical parameters of rocks. Abnormal (high and negative) pressure takes place. This process is called as excitation of the underground environment with periodicity from several tens to several hundreds, or thousand years. The relationship between mud volcanism and the generation of hydrocarbons, particularly methane, is considered to be a critical factor in mud volcano formation. At high flow rates the gas and sediment develops into a pseudo-liquid state and as flow increases the mass reaches the "so-called hover velocity" where mass transport begins. The mass of fluid moves as a quasi-uniform viscous mass through the sediment pile in a piston like manner until expelled from the surface as a "catastrophic eruption

  15. Raman microscopy of synthetic goudeyite (YCu6(AsO4)2(OH)6 x 3H2O).

    PubMed

    Frost, Ray L; Weier, Matt; Martens, Wayde N

    2006-03-01

    Raman microscopy has been used to study the molecular structure of a synthetic goudeyite (YCu(6)(AsO(4))(3)(OH)(6) x 3H(2)O). These types of minerals have a porous framework similar to that of zeolites with a structure based upon (A(3+))(1-x)(A(2+))(x)Cu(6)(OH)(6)(AsO(4))(3-x)(AsO(3)OH)(x). Two sets of AsO stretching vibrations were found and assigned to the vibrational modes of AsO(4) and HAsO(4) units. Two Raman bands are observed in the region 885-915 and 867-870 cm(-1) region and are assigned to the AsO stretching vibrations of (HAsO(4))(2-) and (H(2)AsO(4))(-) units. The position of the bands indicates a C(2v) symmetry of the (H(2)AsO(4))(-) anion. Two bands are found at around 800 and 835 cm(-1) and are assigned to the stretching vibrations of uncomplexed (AsO(4))(3-) units. Bands are observed at around 435, 403 and 395 cm(-1) and are assigned to the nu(2) bending modes of the HAsO(4) (434 and 400 cm(-1)) and the AsO(4) groups (324 cm(-1)).

  16. Raman microscopy of synthetic goudeyite (YCu 6(AsO 4) 2(OH) 6·3H 2O)

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Weier, Matt; Martens, Wayde N.

    2006-03-01

    Raman microscopy has been used to study the molecular structure of a synthetic goudeyite (YCu 6(AsO 4) 3(OH) 6·3H 2O). These types of minerals have a porous framework similar to that of zeolites with a structure based upon (A 3+) 1- x(A 2+) xCu 6(OH) 6(AsO 4) 3- x(AsO 3OH) x. Two sets of AsO stretching vibrations were found and assigned to the vibrational modes of AsO 4 and HAsO 4 units. Two Raman bands are observed in the region 885-915 and 867-870 cm -1 region and are assigned to the AsO stretching vibrations of (HAsO 4) 2- and (H 2AsO 4) - units. The position of the bands indicates a C 2v symmetry of the (H 2AsO 4) - anion. Two bands are found at around 800 and 835 cm -1 and are assigned to the stretching vibrations of uncomplexed (AsO 4) 3- units. Bands are observed at around 435, 403 and 395 cm -1 and are assigned to the ν2 bending modes of the HAsO 4 (434 and 400 cm -1) and the AsO 4 groups (324 cm -1).

  17. Santorini Volcano

    NASA Astrophysics Data System (ADS)

    Heiken, Grant

    What is it about Santorini (Thera) that attracts volcanologists? This small archipelago in the Aegean has captivated volcanic pilgrims since Fouque published his geologic study of the volcanic field in 1879 [Fouqué, 1879].It must be the combination of its spectacular setting, rising out of the blue waters of the Aegean, the remarkable exposures that lay open its violent past for everyone to see, or possibly the slower pace of life and remarkable Greek hospitality Perhaps it is the Lower Bronze Age town of Akrotiri, destroyed yet preserved by a large explosive eruption 3600 years ago. There are thousands of volcanoes yet to be studied on our planet, but for 140 years, groups of volcanologists have regularly visited this flooded caldera complex to add yet another bit of information to the foundation laid by Fouqué.

  18. La variété β-NaMoO2(AsO4)

    PubMed Central

    Ben Hlila, Soumaya; Zid, Mohamed Faouzi; Driss, Ahmed

    2009-01-01

    The title compound, sodium dioxidomolybdenum(VI) arsenate(V), β-NaMoO2AsO4, was prepared by solid-state reaction at 953 K. In the crystal structure, the AsO4 tetra­hedra and MoO6 octa­hedra (both with m symmetry) share corner atoms to form a three-dimensional framework that delimits cavities parallel to [010] where disordered six-coordinated sodium cations (half-occupation) are located. Structural relationships between the different orthoarsenates of the AMoO2AsO4 series (A = Ag, Li, Na, K and Rb) are discussed. PMID:21581739

  19. 78 FR 18314 - Foreign-Trade Zone 169-Manatee County, Florida; Application for Production Authority; ASO, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ... Foreign-Trade Zones Board Foreign-Trade Zone 169--Manatee County, Florida; Application for Production Authority; ASO, LLC; Subzone 169A (Textile Fabric Adhesive Bandage Coating and Production); Sarasota... facility is used for the production of plastic and textile fabric adhesive bandages. ASO is also...

  20. Cladistic analysis applied to the classification of volcanoes

    NASA Astrophysics Data System (ADS)

    Hone, D. W. E.; Mahony, S. H.; Sparks, R. S. J.; Martin, K. T.

    2007-11-01

    Cladistics is a systematic method of classification that groups entities on the basis of sharing similar characteristics in the most parsimonious manner. Here cladistics is applied to the classification of volcanoes using a dataset of 59 Quaternary volcanoes and 129 volcanic edifices of the Tohoku region, Northeast Japan. Volcano and edifice characteristics recorded in the database include attributes of volcano size, chemical composition, dominant eruptive products, volcano morphology, dominant landforms, volcano age and eruptive history. Without characteristics related to time the volcanic edifices divide into two groups, with characters related to volcano size, dominant composition and edifice morphology being the most diagnostic. Analysis including time based characteristics yields four groups with a good correlation between these groups and the two groups from the analysis without time for 108 out of 129 volcanic edifices. Thus when characters are slightly changed the volcanoes still form similar groupings. Analysis of the volcanoes both with and without time yields three groups based on compositional, eruptive products and morphological characters. Spatial clusters of volcanic centres have been recognised in the Tohoku region by Tamura et al. ( Earth Planet Sci Lett 197:105 106, 2002). The groups identified by cladistic analysis are distributed unevenly between the clusters, indicating a tendency for individual clusters to form similar kinds of volcanoes with distinctive but coherent styles of volcanism. Uneven distribution of volcano types between clusters can be explained by variations in dominant magma compositions through time, which are reflected in eruption products and volcanic landforms. Cladistic analysis can be a useful tool for elucidating dynamic igneous processes that could be applied to other regions and globally. Our exploratory study indicates that cladistics has promise as a method for classifying volcanoes and potentially elucidating dynamic

  1. Northern Arizona Volcanoes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, at least one of which buried the homes of local residents. San Francisco Mtn., a truncated stratovolcano at 3887 meters, was once a much taller structure (about 4900 meters) before it exploded some 400,000 years ago a la Mt. St. Helens. The young cinder cone field to its east includes Sunset Crater, that erupted in 1064 and buried Native American homes. This ASTER perspective was created by draping ASTER image data over topographic data from the U.S. Geological Survey National Elevation Data.

    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.

    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 Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) Location: 35.3 degrees North latitude, 111

  2. ESR Study of Electron-Nuclear Dipolar Relaxation for AsO 44-Spin Probe in the Paraelectric Phase of KH 2AsO 4

    NASA Astrophysics Data System (ADS)

    Rakvin, B.; Merunka, D.

    1997-05-01

    Saturation behavior of allowed and forbidden ESR transition of AsO44-paramagnetic probe in KH2AsO4was studied in the wide temperature interval around the paraelectric-ferroelectric phase transition,Tc. The ratios between forbidden and allowed line intensities were employed to deduce information on the electron-nuclear dipolar (END) relaxation mechanism. It was shown that a proton END relaxation mechanism exhibits an extremal temperature behavior in the paraelectric phase around 230 K. The extremal temperature behavior was described by employing a model of proton hopping along the O-H···O bonds around the paramagnetic centers, and the correlation time of this hopping was estimated in the wide temperature range in the paraelectric phase (150-330 K). The temperature dependence of effective proton distance from the neighbor oxygens was obtained, and it was discussed in terms of a localization of the spin density on these oxygens caused by charge inbalance in the As-O bonds in the ferroelectric phase.

  3. 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.

  4. Shiveluch Volcano, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On the night of June 4, 2001, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured this thermal image of the erupting Shiveluch volcano. Located on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 2,447 meters (8,028 feet). The active lava dome complex is seen as a bright (hot) area on the summit of the volcano. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25-kilometer (15-mile) ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred here during the last 10,000 years; the largest historical eruptions were in 1854 and 1964.

    Because Kamchatka is located along the major aircraft routes between North America/Europe and Asia, this area is constantly monitored for potential ash hazards to aircraft. The area is part of the 'Ring of Fire,' a string of volcanoes that encircles the Pacific Ocean.

    The lower image is the same as the upper, except it has been color-coded: red is hot, light greens to dark green are progressively colder, and gray/black are the coldest areas.

    The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

    ASTER is one of five Earth-observing instruments launched Dec. 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. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

  5. Shiveluch Volcano, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On the night of June 4, 2001, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured this thermal image of the erupting Shiveluch volcano. Located on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 2,447 meters (8,028 feet). The active lava dome complex is seen as a bright (hot) area on the summit of the volcano. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25-kilometer (15-mile) ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred here during the last 10,000 years; the largest historical eruptions were in 1854 and 1964.

    Because Kamchatka is located along the major aircraft routes between North America/Europe and Asia, this area is constantly monitored for potential ash hazards to aircraft. The area is part of the 'Ring of Fire,' a string of volcanoes that encircles the Pacific Ocean.

    The lower image is the same as the upper, except it has been color-coded: red is hot, light greens to dark green are progressively colder, and gray/black are the coldest areas.

    The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

    ASTER is one of five Earth-observing instruments launched Dec. 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. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

  6. A Comparison of Ceiling and Visibility Observation for NWS Manned Observation Sites and ASOS Sites

    DTIC Science & Technology

    1993-05-01

    Distribution Diagram ASOS Reports Snow (7.300 data points) . 2. . . . 2W2 E 100 ’- I -1 -50 . . .20 D ifeec ByCtgr jN-SS Fiur 442. cte n rqec...wind. Knowing only the objective result of aerosol scattering within a football size volume of air, gives no indication of what a pilot will encounter

  7. Gaia17aso and Gaia17asp transients confirmed by Euler imaging

    NASA Astrophysics Data System (ADS)

    Blanco-Cuaresma, S.; Roelens, M.; Semaan, T.; Palaversa, L.; Mowlavi, N.; Eyer, L.

    2017-03-01

    We report confirmation of Gaia Science Alerts transients Gaia17aso and Gaia17asp. Images were obtained through modified Gunn R band filter of the ECAM instrument installed on the Swiss 1.2m Euler telescope at La Silla, on 2017 March 21st - 22nd.

  8. K(MoO2)4O3(AsO4)

    PubMed Central

    Jouini, Raja; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    A new compound with a non-centrosymmetric structure, potassium tetra­kis­[dioxomolybdenum(IV)] arsenate trioxide, K(MoO2)4O3(AsO4), has been synthesized by a solid-state reaction. The [(MoO2)4O3(AsO4)]+ three-dimensional framework consists of single arsenate AsO4 tetra­hedra, MoO6 octa­hedra, MoO5 bipyramids and bi­octa­hedral units of edge-sharing Mo2O10 octa­hedra. The [Mo2O8]∞ octa­hedral chains running along the a-axis direction are connected through their corners to the AsO4 tetra­hedra, MoO6 octa­hedra and MoO5 bipyramids, so as to form large tunnels propagating along the a axis in which the K+ cations are located. This structure is compared with compounds containing M 2O10 (M = Mo, V, Fe) dimers and with those containing M 2O8 (M = V) chains. PMID:23794968

  9. Focus: alien volcanos

    NASA Astrophysics Data System (ADS)

    Carroll, Michael; Lopes, Rosaly

    2007-03-01

    Part 1: Volcanoes on Earth - blowing their top; Part 2: Volcanoes of the inner Solar System - dead or alive: the Moon, Mercury, Mars, Venus; Part 3: Volcanoes of the outer Solar System - fire and ice: Io, Europa, Ganymede and Miranda, Titan, Triton, Enceladus.

  10. 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)

  11. 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)

  12. Chiliques volcano, Chile

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24,2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen.

    The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.

    Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.

    These images were acquired 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.

    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 Economy, Trade and Industry. A

  13. Volcano Seismology

    NASA Astrophysics Data System (ADS)

    Chouet, B.

    - A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic

  14. Volcano seismology

    USGS Publications Warehouse

    Chouet, B.

    2003-01-01

    A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic

  15. Cascades Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Driedger, Carolyn; Pallister, John

    2008-01-01

    Washington's Mount St. Helens volcano reawakens explosively on October 1, 2004, after 18 years of quiescence. Scientists at the U.S. Geological Survey's Cascades Volcano Observatory (CVO) study and observe Mount St. Helens and other volcanoes of the Cascade Range in Washington, Oregon, and northern California that hold potential for future eruptions. CVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Mount St. Helens and CVO at http://vulcan.wr.usgs.gov/.

  16. ASTER Images Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2000-01-01

    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

  17. ASTER Images Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2000-01-01

    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

  18. 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.

  19. Geological background and geodynamic mechanism of Mt. Changbai volcanoes on the China-Korea border

    NASA Astrophysics Data System (ADS)

    Liu, Jia-qi; Chen, Shuang-shuang; Guo, Zheng-fu; Guo, Wen-feng; He, Huai-yu; You, Hai-tao; Kim, Hang-min; Sung, Gun-ho; Kim, Haenam

    2015-11-01

    The intense Cenozoic volcanism of Mt. Changbai provides a natural laboratory for investigating the characteristics of volcanism and the dynamical evolution of the Northeast Asian continental margin. Mt. Changbai volcanoes predominantly consist of Wangtian'e volcano in China, Tianchi volcano spanning China and DPR Korea, and Namphothe volcano in DPR Korea. Geochronology data and historical records of volcanism indicate that the three eruption centers were formed in the following sequence: Wangtian'e volcano to Namphothe and Tianchi volcano, advancing temporally and spatially from southwest to northeast. The three eruption centers of Mt. Changbai volcano are located close together, have similar magma evolution trends, bimodal volcanic rock distribution, and an enriched mantle source, etc. Although the Cenozoic volcanism in Mt. Changbai is thought to be somewhat related to the subduction of the Western Pacific Plate, the regularity of volcanic activity and petrography characteristics have continental rift affinity. We therefore conclude that the occurrence of synchronous and similar volcanic activity on both sides of the Japan Sea (i.e., the Japan Arc and Northeast China) likely respond to the rift expansion and the back-arc spreading of Japan Sea. From many perspectives, Mt. Changbai volcano is a giant active volcano with hidden potentially eruptive risks.

  20. Geothermal resources of Kyushu, southwest Japan with special focus on the Kuju volcanic region

    SciTech Connect

    Ehara, S.

    1995-12-31

    Tectonic and geothermal backgrounds of Kyushu Island, are described to understand the thermal regime of Kuju volcano. A model for the geothermal system beneath Kuju volcano is presented based on thermal, isotopic and structural data. Based on the model, the geothermal resources beneath Kuju volcano are classified into five categories and are estimated by a volume method. The volcano energy stored beneath Kuju volcano is one of very promising potential resources in Japan. It would seem more reasonable to develop technologies to utilize volcano energy step by step.

  1. Fusion of multi-temporal Airborne Snow Observatory (ASO) lidar data for mountainous vegetation ecosystems studies.

    NASA Astrophysics Data System (ADS)

    Ferraz, A.; Painter, T. H.; Saatchi, S.; Bormann, K. J.

    2016-12-01

    Fusion of multi-temporal Airborne Snow Observatory (ASO) lidar data for mountainous vegetation ecosystems studies The NASA Jet Propulsion Laboratory developed the Airborne Snow Observatory (ASO), a coupled scanning lidar system and imaging spectrometer, to quantify the spatial distribution of snow volume and dynamics over mountains watersheds (Painter et al., 2015). To do this, ASO weekly over-flights mountainous areas during snowfall and snowmelt seasons. In addition, there are additional flights in snow-off conditions to calculate Digital Terrain Models (DTM). In this study, we focus on the reliability of ASO lidar data to characterize the 3D forest vegetation structure. The density of a single point cloud acquisition is of nearly 1 pt/m2, which is not optimal to properly characterize vegetation. However, ASO covers a given study site up to 14 times a year that enables computing a high-resolution point cloud by merging single acquisitions. In this study, we present a method to automatically register ASO multi-temporal lidar 3D point clouds. Although flight specifications do not change between acquisition dates, lidar datasets might have significant planimetric shifts due to inaccuracies in platform trajectory estimation introduced by the GPS system and drifts of the IMU. There are a large number of methodologies that address the problem of 3D data registration (Gressin et al., 2013). Briefly, they look for common primitive features in both datasets such as buildings corners, structures like electric poles, DTM breaklines or deformations. However, they are not suited for our experiment. First, single acquisition point clouds have low density that makes the extraction of primitive features difficult. Second, the landscape significantly changes between flights due to snowfall and snowmelt. Therefore, we developed a method to automatically register point clouds using tree apexes as keypoints because they are features that are supposed to experience little change

  2. 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.…

  3. 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.…

  4. 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

  5. Study design of SEASON registry: prospective Surveillance of cardiovascular Events in an Antiplatelet-treated arterioSclerosis Obliterans patients in JapaN )SEASON).

    PubMed

    Higashi, Yukihito; Fujita, Masatoshi; Origasa, Hideki; Miyata, Tetsuro; Matsuo, Hiroshi; Naritomi, Hiroaki; Shigematsu, Hiroshi

    2010-01-01

    Antiplatelet therapy is widely performed for arteriosclerosis obliterans (ASO) to relieve ischemic symptoms and prevent cardiovascular events. However, the overall rate of cardiovascular events in patients with ASO under treatment with antiplatelet agents has not been fully investigated in Japan. The SEASON registry is a nationwide observational prospective cohort study designed to compile data from over 2,000 institutions across Japan, whose aims are to (1) understand the current status for the management of ASO and clarify the incidence of cardiovascular events in patients with ASO undergoing antiplatelet therapy, and (2) compare the effectiveness of sarpogrelate, a 5-HT(2A) receptor antagonist, in decreasing the event rate with those of other antiplatelet agents [UMIN ID: UMIN000003385]. The registry will recruit approximately 10,000 patients receiving antiplatelet therapy (8,000 patients for sarpogrelate and 2,000 for other antiplatelet agents), and the patients will be followed every 6 months during a two-year follow-up period. The investigators plan to report all cardiovascular events and exacerbations of ASO. Analysis focusing on the sarpogrelate-treated subgroup will also be performed. Exploratory analysis will be performed to determine the clinical characteristics of the patients and to elucidate the relationships between risk factors and cardiovascular events. The SEASON registry is the first attempt to create a nationwide database regarding the incidence of cardiovascular events in 10,000 ASO patients in Japan. In addition, it ultimately may enable us to conclude that sarpogrelate prevents cardiovascular events. Information on the severity and risk factors in ASO patients in the clinical settings will be applicable to epidemiological analysis.

  6. Galactic Super Volcano Similar to Iceland Volcano

    NASA Image and Video Library

    This composite image from NASAs Chandra X-ray Observatory with radio data from the Very Large Array shows a cosmic volcano being driven by a black hole in the center of the M87 galaxy. This eruptio...

  7. K2V2O2(AsO4)2

    PubMed Central

    Belkhiri, Sabrina; Mezaoui, Djillali; Roisnel, Thierry

    2012-01-01

    The vanadium oxide arsenate with formula K2V2O2(AsO4)2, dipotassium divanadium(IV) dioxide diarsenate, has been synthesized by solid-state reaction in an evacuated silica ampoule. Its structure is isotypic with K2V2O2(PO4)2. The framework is built up from corner-sharing VO6 octa­hedra and AsO4 tetra­hedra, creating an infinite [VAsO8]∞ chain running along the a- and c-axis directions. The K+ cations are located in hexa­gonal tunnels, which are delimited by the connection of the [VAsO8]∞ chains. PMID:22807696

  8. 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.

  9. The Volcano Adventure Guide

    NASA Astrophysics Data System (ADS)

    Goff, Fraser

    2005-05-01

    Adventure travels to volcanoes offer chance encounters with danger, excitement, and romance, plus opportunities to experience scientific enlightenment and culture. To witness a violently erupting volcano and its resulting impacts on landscape, climate, and humanity is a powerful personal encounter with gigantic planetary forces. To study volcano processes and products during eruptions is to walk in the footsteps of Pliny himself. To tour the splendors and horrors of 25 preeminent volcanoes might be the experience of a lifetime, for scientists and nonscientists alike. In The Volcano Adventure Guide, we now have the ultimate tourist volume to lead us safely to many of the world's famous volcanoes and to ensure that we will see the important sites at each one.

  10. Volcanoes, Observations and Impact

    NASA Astrophysics Data System (ADS)

    Thurber, Clifford; Prejean, Stephanie

    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.

  11. Structural features of two novel alluaudite-like arsenates Cd1.16Zn2.34(AsO4)1.5(HAsO4)(H2AsO4)0.5 and Cd0.74Mg2.76(AsO4)1.5(HAsO4)(H2AsO4)0.5

    PubMed Central

    Stojanović, Jovica; Đorđević, Tamara; Karanović, Ljiljana

    2012-01-01

    Two new compounds, Cd1.16Zn2.34(AsO4)1.5(HAsO4)(H2AsO4)0.5 (1) and Cd0.74Mg2.76(AsO4)1.5(HAsO4)(H2AsO4)0.5 (2), have been prepared hydrothermally. Their crystal structures consist of chains of edge-sharing M1O4(OH0.5)2, M1aO4(OH0.5)2, M2O5(OH0.5), and M2aO5(OH0.5) octahedra (M1, M1a = Zn, Cd; M2, M2a = Zn for 1, and M1, M1a = Mg, Cd; M2, M2a = Mg for 2) that are stacked parallel to (1 0 1) and are connected by the [(AsO4)0.5(AsO3(OH))0.5]2.5− and [(AsO4)0.5(AsO2(OH)2)0.5]2− tetrahedra. These chains produce two types of channels parallel to the c-axis. Cd atoms are located in channels 2, while in channels 1 are situated hydrogen atoms of OH groups. The infrared spectra clearly show the presence of broad O—H stretching and bending vibrations centred at 3236, 2392 1575 and 1396 cm−1 in (1), and 3210, 2379 1602 and 1310 cm−1 in (2). The O—H stretching frequency is in good agreement with O⋯O distances. Furthermore, structural characteristics of compounds with similar alluaudite-like structures were discussed. PMID:23471556

  12. Structural features of two novel alluaudite-like arsenates Cd1.16Zn2.34(AsO4)1.5(HAsO4)(H2AsO4)0.5 and Cd0.74Mg2.76(AsO4)1.5(HAsO4)(H2AsO4)0.5.

    PubMed

    Stojanović, Jovica; Dorđević, Tamara; Karanović, Ljiljana

    2012-04-15

    Two new compounds, Cd1.16Zn2.34(AsO4)1.5(HAsO4)(H2AsO4)0.5 (1) and Cd0.74Mg2.76(AsO4)1.5(HAsO4)(H2AsO4)0.5 (2), have been prepared hydrothermally. Their crystal structures consist of chains of edge-sharing M1O4(OH0.5)2, M1aO4(OH0.5)2, M2O5(OH0.5), and M2aO5(OH0.5) octahedra (M1, M1a = Zn, Cd; M2, M2a = Zn for 1, and M1, M1a = Mg, Cd; M2, M2a = Mg for 2) that are stacked parallel to (1 0 1) and are connected by the [(AsO4)0.5(AsO3(OH))0.5](2.5-) and [(AsO4)0.5(AsO2(OH)2)0.5](2-) tetrahedra. These chains produce two types of channels parallel to the c-axis. Cd atoms are located in channels 2, while in channels 1 are situated hydrogen atoms of OH groups. The infrared spectra clearly show the presence of broad O-H stretching and bending vibrations centred at 3236, 2392 1575 and 1396 cm(-1) in (1), and 3210, 2379 1602 and 1310 cm(-1) in (2). The O-H stretching frequency is in good agreement with O⋯O distances. Furthermore, structural characteristics of compounds with similar alluaudite-like structures were discussed.

  13. 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.

  14. 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.

  15. Coupling iSnobal and ASO: Towards an Integrated Water Supply Toolbox for Water Resource Managers

    NASA Astrophysics Data System (ADS)

    Hedrick, A. R.; Marks, D. G.; Havens, S.; Winstral, A. H.; Bormann, K. J.; Skiles, S. M.; Painter, T. H.

    2015-12-01

    Since 2013, airborne lidar surveys have been performed throughout the melt season at near-weekly intervals over the 1,400 km2 Tuolumne River Basin in California's Sierra Nevada Mountains, with the goal of deriving high-resolution measurements of snow depth and reflectance for the NASA Airborne Snow Observatory (ASO). Since the beginning of the campaign, a distributed, physically-based snow model (iSnobal) has been used to estimate the spatial snow density distribution critical for providing accurate SWE products to water managers downstream. An important feature of iSnobal is the ability to stop and then restart using an initialization image constructed from the results of the prior time step. This work examines the effect of assimilating the ASO lidar-derived snow depths to guide the modeled density distribution, since precipitation has been found to be the most difficult parameter to distribute over large mountain basins. Results indicate that the initial model update for each winter is the most significant, with subsequent updates in the absence of severe spring storms having increasingly smaller impacts on the total modeled basin water storage. However, the unprecedented temporal resolution of the ASO lidar surveys provide new insight into the springtime evolution of a large basin snowpack and immensely improve melt timing predictions, which are becoming more and more vital for reservoir management in a changing climate.

  16. K0.8Ag0.2Nb4O9AsO4

    PubMed Central

    Ben Amor, Rym; Zid, Mohamed Faouzi; Driss, Ahmed

    2008-01-01

    The title compound, potassium silver tetra­niobium nona­oxide arsenate, K0.8Ag0.2Nb4O9AsO4, was prepared by a solid-state reaction at 1183 K. The structure consists of infinite (Nb2AsO14)n chains parallel to the b axis and cross-linked by corner sharing via pairs of edge-sharing octa­hedra. Each pair links together four infinite chains to form a three-dimensional framework. The K+ and Ag+ ions partially occupy several independent close positions in the inter­connected cavities delimited by the framework. K0.8Ag0.2Nb4O9AsO4 is likely to exhibit fast alkali-ion mobility and ion-exchange properties. The Wyckoff symbols of special positions are as follows: one Nb 8e, one Nb 8g, As 4c, two K 8f, one Ag 8f, one Ag 4c, one O 8g, one O 4c. PMID:21202442

  17. NaAg2Mo3O9AsO4

    PubMed Central

    Hamza, Hamadi; Zid, Mohamed Faouzi; Driss, Ahmed

    2010-01-01

    The title compound, sodium disilver arsenatotrimolybdate, Na0.93 (1)Ag2.07 (1)Mo3AsO13, was prepared by a solid-state reaction. In the crystal structure, isolated AsO4 tetra­hedra share corners with groups of three edge-sharing MoO6 octa­hedra. This arrangement leads to the formation of anionic 1 ∞[Mo3AsO13]n ribbons extending parallel to [100]. The three metal sites show occupational disorder by AgI and NaI cations, each with a different Ag:Na ratio. The metal cations are situated in the space between the ribbons and are surrounded by terminal O atoms of the ribbons in the form of distorted MO7 polyhedra (M = Ag, Na) for distances < 3.0 Å. The title compound shows weak ionic conductivity. Structural relationships between different compounds in the quaternary systems M–Sb–P–O, M–Nb–P–O and M–Mo–As–O (M is Ag or an alkali metal) are also discussed. PMID:21587345

  18. K0.78Na0.22MoO2AsO4

    PubMed Central

    Jouini, Raja; Bouzidi, Chahira; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    The title compound, potassium sodium dioxidomolybden­um(VI) arsenate, K0.78Na0.22MoO2AsO4, was synthesized by a solid-state reaction route. The structure is built up from corner-sharing MoO6 octa­hedra and AsO4 tetra­hedra, creating infinite [MoAsO8]∞ chains running along the b-axis direction. As, Mo and all but one O atom are on special positions (4c) with m symmetry and K (occupancy 0.78) is on a position (4a) of -1 in the tunnels. The possible motion of the alkali cations has been investigated by means of the bond-valance sum (BVS) model. The simulation shows that the Na+ motion appears to be easier mainly along the b-axis direction. Structural relationships between the different compounds of the AMoO2AsO4 (A = Ag, Li, Na, K, Rb) series and MXO8 (M = V; X = P, As) chains are discussed. PMID:24109253

  19. 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

  20. 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.

  1. Yellowstone Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Lowenstern, Jacob

    2008-01-01

    Eruption of Yellowstone's Old Faithful Geyser. Yellowstone hosts the world's largest and most diverse collection of natural thermal features, which are the surface expression of magmatic heat at shallow depths in the crust. The Yellowstone system is monitored by the Yellowstone Volcano Observatory (YVO), a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and the University of Utah. YVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Yellowstone and YVO at http://volcanoes.usgs.gov/yvo.

  2. 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.

  3. Distant Mt. Fuji, Island of Honshu Japan

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This distant view of Mt. Fuji, on the main home island of Honshu, Japan (34.0N, 139.0E) was taken from about 450 miles to the south. Evan at that great distance, the majestic and inspiring Mt. Fuji is still plainly visible and easily recognized as a world renowned symbol of Japan. The snow capped extinct volcano lies just a few miles south of Tokyo.

  4. Distant Mt. Fuji, Island of Honshu Japan

    NASA Image and Video Library

    1992-11-01

    This distant view of Mt. Fuji, on the main home island of Honshu, Japan (34.0N, 139.0E) was taken from about 450 miles to the south. Evan at that great distance, the majestic and inspiring Mt. Fuji is still plainly visible and easily recognized as a world renowned symbol of Japan. The snow capped extinct volcano lies just a few miles south of Tokyo.

  5. 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

  6. Volcano infrasound: A review

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey Bruce; Ripepe, Maurizio

    2011-09-01

    Exploding volcanoes, which produce intense infrasound, are reminiscent of the veritable explosion of volcano infrasound papers published during the last decade. Volcano infrasound is effective for tracking and quantifying eruptive phenomena because it corresponds to activity occurring near and around the volcanic vent, as opposed to seismic signals, which are generated by both surface and internal volcanic processes. As with seismology, infrasound can be recorded remotely, during inclement weather, or in the dark to provide a continuous record of a volcano's unrest. Moreover, it can also be exploited at regional or global distances, where seismic monitoring has limited efficacy. This paper provides a literature overview of the current state of the field and summarizes applications of infrasound as a tool for better understanding volcanic activity. Many infrasound studies have focused on integration with other geophysical data, including seismic, thermal, electromagnetic radiation, and gas spectroscopy and they have generally improved our understanding of eruption dynamics. Other work has incorporated infrasound into volcano surveillance to enhance capabilities for monitoring hazardous volcanoes and reducing risk. This paper aims to provide an overview of volcano airwave studies (from analog microbarometer to modern pressure transducer) and summarizes how infrasound is currently used to infer eruption dynamics. It also outlines the relative merits of local and regional infrasound surveillance, highlights differences between array and network sensor topologies, and concludes with mention of sensor technologies appropriate for volcano infrasound study.

  7. 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.

  8. Analysis of Distribution of Volcanoes around the Korean Peninsula and the Potential Effects on Korea

    NASA Astrophysics Data System (ADS)

    Choi, Eun-kyeong; Kim, Sung-wook

    2017-04-01

    Since the scale and disaster characteristics of volcanic eruptions are determined by their geological features, it is important not only to grasp the current states of the volcanoes in neighboring countries around the Korean Peninsula, but also to analyze the tectonic settings, tectonic regions, geological features, volcanic types, and eruption histories of these volcanoes. Volcanic data were based on the volcano information registered with the Global Volcanism Program at the Smithsonian Institute. We created a database of 289 volcanoes around Korea, Japan, China, Taiwan, and the Kamchatka area in Russia, and then identified a high-risk group of 29 volcanoes that are highly likely to affect the region, based on conditions such as volcanic activity, types of rock at risk of eruption, distance from Seoul, and volcanoes having Plinian eruption history with volcanic explosivity index (VEI) of 4 or more. We selected 29 hazardous volcanoes, including Baekdusan, Ulleungdo, and 27 Japanese volcanoes that can cause widespread ashfall on the Korean peninsula by potentially explosive eruptions. In addition, we identified ten volcanoes that should be given the highest priority, through an analysis of data available in literature, such as volcanic ash dispersion results from previous Japanese eruptions, the definition of a large-scale volcano used by Japan's Cabinet Office, and examination of cumulative magma layer volumes from Japan's quaternary volcanoes. We expect that predicting the extent of the spread of ash caused by this hazardous activity and analyzing its impact on the Korean peninsula will be help to predict volcanic ash damage as well as provide direction for hazard mitigation research. Acknowledgements This research was supported by a grant [MPSS-NH-2015-81] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

  9. Soufriere Hills Volcano Resumes Activity

    NASA Image and Video Library

    2017-09-27

    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

  10. 3-D Dynamic rupture simulation for the 2016 Kumamoto, Japan, earthquake sequence: Foreshocks and M6 dynamically triggered event

    NASA Astrophysics Data System (ADS)

    Ando, R.; Aoki, Y.; Uchide, T.; Imanishi, K.; Matsumoto, S.; Nishimura, T.

    2016-12-01

    A couple of interesting earthquake rupture phenomena were observed associated with the sequence of the 2016 Kumamoto, Japan, earthquake sequence. The sequence includes the April 15, 2016, Mw 7.0, mainshock, which was preceded by multiple M6-class foreshock. The mainshock mainly broke the Futagawa fault segment striking NE-SW direction extending over 50km, and it further triggered a M6-class earthquake beyond the distance more than 50km to the northeast (Uchide et al., 2016, submitted), where an active volcano is situated. Compiling the data of seismic analysis and InSAR, we presumed this dynamic triggering event occurred on an active fault known as Yufuin fault (Ando et al., 2016, JPGU general assembly). It is also reported that the coseismic slip was significantly large at a shallow portion of Futagawa Fault near Aso volcano. Since the seismogenic depth becomes significantly shallower in these two areas, we presume the geothermal anomaly play a role as well as the elasto-dynamic processes associated with the coseismic rupture. In this study, we conducted a set of fully dynamic simulations of the earthquake rupture process by assuming the inferred 3D fault geometry and the regional stress field obtained referring the stress tensor inversion. As a result, we showed that the dynamic rupture process was mainly controlled by the irregularity of the fault geometry subjected to the gently varying regional stress field. The foreshocks ruptures have been arrested at the juncture of the branch faults. We also show that the dynamic triggering of M-6 class earthquakes occurred along the Yufuin fault segment (located 50 km NE) because of the strong stress transient up to a few hundreds of kPa due to the rupture directivity effect of the M-7 event. It is also shown that the geothermal condition may lead to the susceptible condition of the dynamic triggering by considering the plastic shear zone on the down dip extension of the Yufuin segment, situated in the vicinity of an

  11. Stress, strain rate and anisotropy in Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Savage, M. K.; Aoki, Y.; Unglert, K.; Ohkura, T.; Umakoshi, K.; Shimizu, H.; Iguchi, M.; Tameguri, T.; Ohminato, T.; Mori, J.

    2016-04-01

    Seismic anisotropy, the directional dependence of wave speeds, may be caused by stress-oriented cracks or by strain-oriented minerals, yet few studies have quantitatively compared anisotropy to stress and strain over large regions. Here we compare crustal stress and strain rates on the Island of Kyushu, Japan, as measured from inversions of focal mechanisms, GPS and shear wave splitting. Over 85,000 shear wave splitting measurements from local and regional earthquakes are obtained from the NIED network between 2004 and 2012, and on Aso, Sakurajima, Kirishima and Unzen volcano networks. Strain rate measurements are made from the Japanese Geonet stations. JMA-determined S arrival times processed with the MFAST shear wave splitting code measure fast polarisations (Φ), related to the orientation of the anisotropic medium and time delays (dt), related to the path length and the percent anisotropy. We apply the TESSA 2-D delay time tomography and spatial averaging code to the highest quality events, which have nearly vertical incidence angles, separating the 3455 shallow (depth < 40 km) from the 4957 deep (> = 40 km) earthquakes. Using square grids with 30 km sides for all the inversions, the best correlations are observed between splitting from shallow earthquakes and stress. Axes of maximum horizontal stress (SHmax) and Φ correlate with a coefficient c of 0.56, significant at the 99% confidence level. Their mean difference is 31.9°. Axes of maximum compressional strain rate and SHmax are also well aligned, with an average difference of 28°, but they do not correlate with each other, meaning that where they differ, the difference is not systematic. Anisotropy strength is negatively correlated with the stress ratio parameter determined from focal mechanism inversion (c = - 0.64; significant at the 99% confidence level). The anisotropy and stress results are consistent with stress-aligned microcracks in the crust in a dominantly strike-slip regime. Eigenvalues of

  12. 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

  13. 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

  14. 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.

  15. Development of Grounded Electrical Source Airborne Transient EM (GREATEM) Survey System and Its Application to Investigating a Volcano Structure

    NASA Astrophysics Data System (ADS)

    Mogi, T.; Jomori, A.; Jomori, N.; Azuma, Y.; Fomenko, E. Y.

    2005-12-01

    three-component magnetic filed, tilting, time and positioning are digitized at 25 kHz for 10 channels. We have also developed a 3D modeling scheme to investigate magnetic field responses in the air for complicated subsurface structure and topography. We carried out GREATEM surveys at Aso Volcano, southwest Japan to test the survey system and clarify the subsurface structure of the volcano. We computed the transient response of the magnetic field in the air by removing motion noise and other EM noise using special digital filters. Finally we obtained resistivity structure, assuming horizontal layer structure. The depth of investigation of present survey was estimated about 800m deep.

  16. Alaska - Kamchatka Connection in Volcano Monitoring, Research, and Education

    NASA Astrophysics Data System (ADS)

    Izbekov, P. E.; Gordeev, E.; Eichelberger, J. C.; Neal, C. A.

    2009-12-01

    The Aleutian-Kamchatka portion of the Pacific Rim of Fire spans ~4400 km. This segment contains more than 80 active volcanoes and averages 4-6 eruptions per year. Resulting ash clouds travel for hundreds to thousands of kilometers defying political borders. To mitigate volcano hazard to aviation and local communities, the Alaska Volcano Observatory (AVO) and the Institute of Volcanology and Seismology (IVS), in partnership with the Kamchatkan Branch of the Geophysical Survey of the Russian Academy of Sciences (KBGS), have established a collaborative program with three important components: (1) volcano monitoring with rapid information exchange, (2) cooperation in research projects at active volcanoes, and (3) a series of volcanological schools for students and young scientists. Cooperation in volcano monitoring includes dissemination of daily information on the state of volcanic activity in neighboring regions, satellite and visual data exchange, as well as sharing expertise and technologies between AVO and the Kamchatkan Volcanic Eruption Response Team (KVERT), formed in 1993 under the auspices of both IVS and KBGS. Collaboration in scientific research is best illustrated by involvement of AVO, IVS, and KBGS faculty and graduate students in mutual international studies. One of the most recent examples is the NSF-funded Partnerships for International Research and Education (PIRE)-Kamchatka project focusing on multi-disciplinary study of Bezymianny volcano in Kamchatka. This international project is one of many that have been initiated as a direct result of a bi-annual series of meetings known as Japan-Kamchatka-Alaska Subduction Processes (JKASP) workshops that we organize together with colleagues from Hokkaido University, Japan. The most recent JKASP meeting was held in June 2009 in Fairbanks, Alaska and brought together more than 150 scientists and students. The key educational component of our collaborative program is the continuous series of international

  17. 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.

  18. Volcano Chaiten, Chile

    NASA Image and Video Library

    2009-05-15

    Chaiten Volcano, Chile continues to erupt after first exploding in May 2008 following about 9,000 years of inactivity. This image from NASA Terra spacecraft shows vegetation in red. You can clearly see the extent of the plume.

  19. Northern Arizona Volcanoes

    NASA Image and Video Library

    2006-05-01

    Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, at least one of which buried the homes of local residents. This image was acquired by NASA Terra spacecraft.

  20. FOREWORD: The 9th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas (ASOS 9)

    NASA Astrophysics Data System (ADS)

    Wahlgren, Glenn M.; Wiese, Wolfgang L.; Beiersdorfer, Peter

    2008-07-01

    For the first time since its inaugural meeting in Lund in 1983, the triennial international conference on Atomic Spectroscopy and Oscillator Strengths for Astrophysical and Laboratory Plasmas (ASOS) returned to Lund, Sweden. Lund has been a home to atomic spectroscopy since the time of Janne Rydberg, and included the pioneering work in laboratory and solar spectroscopy of Bengt Edlén, who presented the initial ASOS talk in 1983. The ninth ASOS was hosted by the Lund Observatory and the Physics Department of Lund University during from 8 to 10 August 2007 and was attended by nearly 100 registrants. An encouraging sign for the field was the number of young researchers in attendance. This volume contains the submitted contributions from the poster presentations of the conference, and represents approximately forty percent of the presented posters. A complementary volume of Physica Scripta provides the written transactions of the ASOS9 invited presentations. With these two volumes the character of ASOS9 is more fully evident, and they serve as a review of the state of atomic spectroscopy for spectrum analysis and the determination of oscillator strengths and their applications. The goal of ASOS is to be a forum for atomic spectroscopy where both the providers and users of atomic data, which includes wavelengths, energy levels, lifetimes, oscillator strengths, and line shape parameters, can meet to discuss recent advances in experimental and theoretical techniques and their application to understanding the physical processes that are responsible for producing observed spectra. The applications mainly originate from the fields of astrophysics and plasma physics, the latter including fusion energy and lighting research. As a part of ASOS9 we were honored to celebrate the retirement of Professor Sveneric Johansson. At a special session on the spectroscopy of iron, which was conducted in his honor, he presented his insights into the Fe II term system and his most recent

  1. 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.

  2. A Rapid Turn-around, Scalable Big Data Processing Capability for the JPL Airborne Snow Observatory (ASO) Mission

    NASA Astrophysics Data System (ADS)

    Mattmann, C. A.

    2014-12-01

    The JPL Airborne Snow Observatory (ASO) is an integrated LIDAR and Spectrometer measuring snow depth and rate of snow melt in the Sierra Nevadas, specifically, the Tuolumne River Basin, Sierra Nevada, California above the O'Shaughnessy Dam of the Hetch Hetchy reservoir, and the Uncompahgre Basin, Colorado, amongst other sites. The ASO data was delivered to water resource managers from the California Department of Water Resources in under 24 hours from the time that the Twin Otter aircraft landed in Mammoth Lakes, CA to the time disks were plugged in to the ASO Mobile Compute System (MCS) deployed at the Sierra Nevada Aquatic Research Laboratory (SNARL) near the airport. ASO performed weekly flights and each flight took between 500GB to 1 Terabyte of raw data, which was then processed from level 0 data products all the way to full level 4 maps of Snow Water Equivalent, albedo mosaics, and snow depth from LIDAR. These data were produced by Interactive Data analysis Language (IDL) algorithms which were then unobtrusively and automatically integrated into an Apache OODT and Apache Tika based Big Data processing system. Data movement was both electronic and physical including novel uses of LaCie 1 and 2 TeraByte (TB) data bricks and deployment in rugged terrain. The MCS was controlled remotely from the Jet Propulsion Laboratory, California Institute of Technology (JPL) in Pasadena, California on behalf of the National Aeronautics and Space Administration (NASA). Communication was aided through the use of novel Internet Relay Chat (IRC) command and control mechanisms and through the use of the Notifico open source communication tools. This talk will describe the high powered, and light-weight Big Data processing system that we developed for ASO and its implications more broadly for airborne missions at NASA and throughout the government. The lessons learned from ASO show the potential to have a large impact in the development of Big Data processing systems in the years

  3. The NASA Airborne Snow Observatory: Demonstration Mission-3 and the Path Forward to a Broader ASO Program

    NASA Astrophysics Data System (ADS)

    Painter, T. H.

    2015-12-01

    The NASA Airborne Snow Observatory (ASO), an imaging spectrometer and imaging LiDAR system, to quantify snow water equivalent and snow albedo, provide unprecedented knowledge of snow properties, and provide complete, robust inputs to snowmelt runoff models, water management models, and systems of the future. This talk presents results from the third Demonstration Mission that occurred during the intense California drought of spring 2015, a snow year far worse than the previously worst snow year on record of 2014, and an overview of the various analyses that are finally available due to the uniqueness of the ASO data. In 2015, ASO provided complete basin coverage for the Tuolumne, Merced, Lakes, Rush Creek, and Middle+South Forks of Kings River Basins in the California Sierra Nevada and the Upper Rio Grande, Conejos, and Uncompahgre Basins in the Colorado Rocky Mountains. ASO performed its first wintertime acquisitions in the Tuolumne Basin in response to water managers' needs to quantify SWE volume in what was already realized as dire conditions. Analyses show that with ASO data, river flows and reservoir inflows from the ASO acquisition date to 1 July can be estimated with uncertainties of less than 2%. These results provide enormous value in management operational flexibility for the diversity of needs, and provide strong scientific constraints on the physical processes controlling snowmelt runoff. Snowmelt runoff models are markedly better constrained due to the now accurate knowledge of the distribution of snow water equivalent. With the ASO high-resolution spectrometer and lidar data for a snow-free acquisition, we can determine surface classifications, vegetation heights, and river networks. These data allow runoff models to be accurately and rapidly developed with unprecedented accuracy. These data are now being used to constrain models of varying complexity. Finally, we discuss the path forward on expanding ASO to cover the entire Sierra Nevada and the

  4. Theoretical and experimental study of the vibrational spectra of sarkinite Mn2(AsO4)(OH) and adamite Zn2(AsO4)(OH)

    NASA Astrophysics Data System (ADS)

    Makreski, Petre; Jovanovski, Stefan; Pejov, Ljupco; Kloess, Gert; Hoebler, Hans-Joachim; Jovanovski, Gligor

    2013-09-01

    The arsenate hydroxyl-bearing minerals sarkinite and adamite were studied with vibrational spectroscopic (IR and Raman) and quantum theoretical methods. The observed IR bands in the higher (1100-600 cm-1) and especially lower (600-450 cm-1) frequency region of AsO4 vibrations could clearly discriminate between the studied analogues. The differences between their crystal structures are much pronounced in both IR and Raman OH-stretching regions. Namely, a single strong band is found in the case of orthorhombic adamite compared to four weaker bands observed in corresponding IR and Raman spectral regions of monoclinic sarkinite. Essentially all bands in the experimental spectra, collected at both room and liquid nitrogen temperature, were tentatively assigned. To support the tentative assignment of bands in the vibrational spectra of the mentioned minerals, periodic pseudopotential plane wave density functional theory calculations were carried out. Geometry optimizations of the 3D periodic systems included both optimizations of the atomic positions within the unit cell and of the unit cell itself. In most cases, the assignments were either supported or implied by the obtained theoretical data. It is worth mentioning that this is the first experimental and theoretical study of the vibrational spectra of the very-rare sarkinite mineral.

  5. Current status of the medical expenses for the treatment of arteriosclerosis obliterans in Japan.

    PubMed

    Isaji, T; Takayama, T; Endo, A; Akai, A; Kudo, M; Kagaya, H; Suzuki, J; Hashimoto, T; Hoshina, K; Kimura, H; Okamoto, H; Shigematsu, K; Miyata, T

    2010-04-01

    We aimed to determine the current status of the medical expenses for the treatment of arteriosclerosis obliterans (ASO) and evaluate the cost effectiveness of the medical practices employed in ASO treatment in Japan. We performed a prospective observational study using 140 ASO patients. The cost of the medical practices comprised the costs of outpatient treatment, pharmacological agents, and hospitalization. To compare the average monthly costs, the patients were divided into preintervention, postintervention, or conservative-therapy groups. To compare the total costs and effectiveness of each treatment, the patients who had first visited our division during the study period were classified into surgery, endovascular-revascularization (EVR), or conservative-therapy groups. The adverse reactions of the 4 most popular agents for ASO were investigated, and bleeding events were assessed specifically. The average monthly costs for outpatient treatment and pharmacological agents were yen 168,002 in conservative cases, yen 149,871 in preoperation cases, and yen 128,527 in postoperation cases. The mean total costs were yen 5,407,950 in conservative cases, yen 7,375,290 in surgical cases, and yen 2,631,650 in EVR cases. The average change of the gauge in clinical status was 0.57 in conservative cases, 2.13 in surgical cases, and 2.25 in EVR cases. Warfarin induced more bleeding complications than the other agents. The costs of pharmacological agents represented much of the medical costs in any treatment groups.

  6. Stereo Image of Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2002-01-01

    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. This anaglyph stereo image is of Mt Usu volcano. On Friday, March 31, more than 15,000 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. A 3-D view can be obtained by looking through stereo glasses, with the blue film through your left eye and red film with your right eye at the same time. North is on your right hand side. For more information, see When Rivers of Rock Flow ASTER web page Image courtesy of MITI, ERSDAC, JAROS, and the U.S./Japan ASTER Science Team

  7. 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)

  8. 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)

  9. 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

  10. Amelioration of diet-induced steatohepatitis in mice following combined therapy with ASO-Fsp27 and fenofibrate.

    PubMed

    Rajamoorthi, Ananthi; Arias, Noemi; Basta, Jeannine; Lee, Richard G; Baldán, Ángel

    2017-09-05

    Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD progresses from benign steatosis to steatohepatitis (NASH) to cirrhosis, and is linked to hepatocellular carcinoma. No targeted treatment is currently approved for NAFLD/NASH. We showed that fat-specific protein 27 (FSP27), a lipid droplet-associated protein that controls triglyceride turnover in the hepatocyte, is required for fasting- and diet-induced triglyceride accumulation in the liver. However, silencing Fsp27 with antisense oligonucleotides (ASOs) did not improve hepatosteatosis in genetic nor nutritional mouse models of obesity. Herein, we tested the therapeutic potential of ASO-Fsp27 when used in combination with the PPARα agonist fenofibrate. C57BL/6 mice were fed a high-trans-fat, high-cholesterol, high-fructose diet for 8 weeks to establish NASH, then kept on diet for 6 additional weeks while dosed with ASOs and fenofibrate, alone or in combination. Data show that ASO-Fsp27 and fenofibrate synergize to promote resistance to diet-induced obesity and hypertriglyceridemia, and to reverse hepatic steatosis, inflammation, oxidative stress, and fibrosis. This multifactorial improvement of liver disease noted when combining both drugs suggests that a course of treatment that includes both reduced FSP27 activity and activation of PPARα could provide therapeutic benefit to patients with NAFLD/NASH. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  11. 75 FR 59695 - Foreign-Trade Zone 169-Manatee County, Florida; Extension of Subzone; Aso LLC (Adhesive Bandage...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 169--Manatee County, Florida; Extension of Subzone; Aso LLC... Zones Board (the Board) by the Manatee County Port Authority, grantee of FTZ 169, requesting to...

  12. Japan Report.

    DTIC Science & Technology

    1987-02-03

    10503« JPRS-JAR-87-001 3 FEBRUARY 1987 Japan Report 19980629 058 FBIS FOREIGN BROADCAST INFORMATION SERVICE BTIO QUALITY INSPECTED 6... JAPAN REPORT CONTENTS POLITICAL AND SOCIOLOGICAL Impact of Miyazawa’s Appointment as Finance Minister (Kenzo Uchida, et al.; ZAIKAI TEMBO, Oct 86...Direct U.S. Investment Discussed (Akio Morita, et? al.; KEIDANREN GEPPO, Sep 86) 30 Japan -PRC Trade Expansion Council Officially Inaugurated

  13. Japan Report.

    DTIC Science & Technology

    1985-04-30

    172068 JPRS-JAR-85-0 1 0 3 0 April 198 5 Japan Report 19980722 116 »TIC QUALITY SfSPECTED 3 FBIS FOREIGN BROADCAST INFORMATION SERVICE...85-010 30 April 19 85 JAPAN REPORT CONTENTS POLITICAL AND SOCIOLOGICAL Break Up of Tanaka-Nakasone Alliance Anticipated (Taro Maki; SEKAI, Jan 85...minister. It became "When I was prime minister, Japan was isolated in international society," and although at the U.S.- Japan summit talks President Reagan

  14. Japan Report.

    DTIC Science & Technology

    1985-05-09

    expenditure . He said that he hoped for greater effort on Japan’s part in regard to the defense of Japan itself and its periphery. This means he clearly set...Forces into real combat forces and their unification with U.S. Forces. They dealt with the mounting defense expenditure , which is also connected with...governments of Japan and the United States on "guidelines for Japan -U.S. cooperation on defense " in 1978. Throughout 1984, even Prime Minister Nakasone

  15. Eruption of Kliuchevskoi volcano

    NASA Image and Video Library

    1994-10-09

    STS068-258-028 (9 October 1994) --- Astronauts aboard the Space Shuttle Endeavour recorded this final 70mm frame of the Kliuchevskoi volcano on the Kamchatka Peninsula in Russia. The volcano was near its peak on launch day, 10 days earlier, but a snowstorm left very little indication of the major event that had occurred here, except for the ash-covered summit and the large black flow down the northern flank of the mountain. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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).

  20. Eruption of Kliuchevskoi volcano

    NASA Image and Video Library

    1994-09-30

    STS068-150-045 (30 September 1994) --- (Kliuchevskoi Volcano) The major eruption that began September 30, 1994 (launch day) got almost immediate coverage by the astronauts aboard the Space Shuttle Endeavour. The eruption cloud reached 60,000 feet above sea level, and the winds carried ash as far as 640 miles southeast from the volcano into the North Pacific air routes. This picture was made with a large format Linhof camera. While astronauts used handheld camera's to keep up with the Kamchatka event, instruments in the cargo bay of Endeavour recorded data to support the Space Radar Laboratory (SRL-2) mission.

  1. Volcano-electromagnetic effects

    USGS Publications Warehouse

    Johnston, Malcolm J. S.

    2007-01-01

    Volcano-electromagnetic effects—electromagnetic (EM) signals generated by volcanic activity—derive from a variety of physical processes. These include piezomagnetic effects, electrokinetic effects, fluid vaporization, thermal demagnetization/remagnetization, resistivity changes, thermochemical effects, magnetohydrodynamic effects, and blast-excited traveling ionospheric disturbances (TIDs). Identification of different physical processes and their interdependence is often possible with multiparameter monitoring, now common on volcanoes, since many of these processes occur with different timescales and some are simultaneously identified in other geophysical data (deformation, seismic, gas, ionospheric disturbances, etc.). EM monitoring plays an important part in understanding these processes.

  2. 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

  3. CsAl(H(2)AsO(4))(2)(HAsO(4)): a new monoclinic protonated arsenate with decorated kröhnkite-like chains.

    PubMed

    Schwendtner, Karolina; Kolitsch, Uwe

    2007-03-01

    The crystal structure of hydrothermally synthesized caesium aluminium bis[dihydrogen arsenate(V)] hydrogen arsenate(V), CsAl(H(2)AsO(4))(2)(HAsO(4)), was determined from single-crystal X-ray diffraction data collected at room temperature. The compound represents a new structure type that is characterized by decorated kröhnkite-like [100] chains of corner-sharing AlO(6) octahedra and AsO(4) tetrahedra. Ten-coordinated Cs atoms are situated between the chains, which are interconnected by five different hydrogen bonds [O...O = 2.569 (4)-2.978 (4) A]. All atoms are in general positions. CsAl(H(2)AsO(4))(2)(HAsO(4)) is very closely related to CsGa(H(1.5)AsO(4))(2)(H(2)AsO(4)) and isotypic CsCr(H(1.5)AsO(4))(2)(H(2)AsO(4)).

  4. Stabilin-1 and Stabilin-2 are specific receptors for the cellular internalization of phosphorothioate-modified antisense oligonucleotides (ASOs) in the liver

    PubMed Central

    Miller, Colton M.; Donner, Aaron J.; Blank, Emma E.; Egger, Andrew W.; Kellar, Brianna M.; Østergaard, Michael E.; Seth, Punit P.; Harris, Edward N.

    2016-01-01

    Phosphorothioate (PS)-modified antisense oligonucleotides (ASOs) have been extensively investigated over the past three decades as pharmacological and therapeutic agents. One second generation ASO, Kynamro™, was recently approved by the FDA for the treatment of homozygous familial hypercholesterolemia and over 35 second generation PS ASOs are at various stages of clinical development. In this report, we show that the Stabilin class of scavenger receptors, which were not previously thought to bind DNA, do bind and internalize PS ASOs. With the use of primary cells from mouse and rat livers and recombinant cell lines each expressing Stabilin-1 and each isoform of Stabilin-2 (315-HARE and 190-HARE), we have determined that PS ASOs bind with high affinity and these receptors are responsible for bulk, clathrin-mediated endocytosis within the cell. Binding is primarily dependent on salt-bridge formation and correct folding of the intact protein receptor. Increased internalization rates also enhanced ASO potency for reducing expression of the non-coding RNA Malat-1, in Stabilin-expressing cell lines. A more thorough understanding of mechanisms by which ASOs are internalized in cells and their intracellular trafficking pathways will aid in the design of next generation antisense agents with improved therapeutic properties. PMID:26908652

  5. Japan: Tsunami

    Atmospheric Science Data Center

    2013-04-16

    article title:  Tsunami Inundation Along Japan's Eastern Coast   ... The extent of inundation from the destructive and deadly tsunami triggered by the March 11, 2011, magnitude 8.9 earthquake centered off ... March 16, 2001 and March 12, 2011 - Before and after tsunami inundation along Japan's eastern coast. project:  ...

  6. Tokyo, Japan

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Tokyo, (35.5N, 140.0E) the capital city of Japan, Tokyo Bay and the neighboring cities of Yokohama, Kawasaki and Chiba are seen in this view of Japan. This great international seaport facility covers almost all of the bayfront and is home to over thirty million people.

  7. Update Japan.

    ERIC Educational Resources Information Center

    Hoopes, Aaron

    This book is a guide intended for persons planning on relocating to Japan. Following a chapter on background information, 13 additional chapters lead the reader step-by-step through the relocation process. These chapters include: before leaving, on arrival, language, culture, doing business in Japan, household pointers and everyday life, schools…

  8. Evolution of the 120 ka caldera-forming eruption of Kutcharo volcano, eastern Hokkaido, Japan: Geologic and petrologic evidence for multiple vent systems and rapid generation of pyroclastic flow

    NASA Astrophysics Data System (ADS)

    Hasegawa, Takeshi; Matsumoto, Akiko; Nakagawa, Mitsuhiro

    2016-07-01

    We investigated the eruptive sequence and temporal evolution of juvenile materials during the 120 ka Kutcharo pumice flow IV (Kp IV) eruption, which was the most voluminous (175 km3: bulk volume) caldera-forming eruption of Kutcharo volcano. The eruptive deposits are divided into four units in ascending order. Unit 1 is widely dispersed and consists of silt-sized, cohesive ash. Unit 2 is a thin, moderately sorted pumice fall deposit with a restricted distribution and small volume (< 0.2 km3). Unit 3, consisting of widely distributed ignimbrite, is the most voluminous. Unit 4 is also composed of pyroclastic flow deposits, but its distribution is limited to the northwest side of the caldera. Juvenile materials consist mainly of rhyolite pumice (74%-78% SiO2) associated with a minor amount of scoria (52%-73% SiO2) that are found only northwest of the caldera in Unit 3 and Unit 4. These scoriae can be classified on the basis of the P2O5 contents of their matrix glass into low-P, medium-P, and high-P types, which are almost entirely restricted to the lower part of Unit 3, Unit 4, and the upper part of Unit 3, respectively. These three types display distinct mixing trends with the rhyolitic compositions in SiO2-P2O5 variation diagrams. This evidence indicates that three distinct mafic magmas were independently and intermittently injected into the main body of silicic magma to erupt from the northwestern part of the magma system. Mafic injections did not occur in the southern part of the magma system. This petrologic evidence implies that the northwestern and southeastern flows of Unit 3 are heterotopic, contemporaneous products derived from multiple vent systems. Although Unit 2 was derived from an eruptive column, its volume is very small compared to Plinian fall deposits of typical caldera-forming eruptions. In our interpretation, the activity of the Kp IV eruption reached its climax rapidly, depositing Unit 3, without first producing a stable Plinian column. The

  9. 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.

  10. Volcano evolution on Mars

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, Pete; Wilson, Lionel

    1987-01-01

    The diversity of volcanic activity on Mars throughout geologic time was one of the major factors that has controlled the spatial distribution of surface mineralogies. The traditional view of Martian volcanism is one in which effusive activity has dominated the entire preserved geologic history of the planet, with the minor exception of phreatomagnetic activity and associated volcano ground-ice interactions. However, two lines of evidence have caused reconsidering of this view, and have led to the possible role of explosive volcanism on Mars. First, detailed analysis of high resolution Viking Orbiter images has provided good evidence for explosive activity on Hecates Tholus and Alba Patera. Secondly, the problems believed to exist in associating explosive volcanism with silicic magmas on Mars, and the consequent unusual magmatic evolutionary trend for Martian volcanoes from silica-rich to silica-poor, may now be circumvented by the consideration of basatic plinian activity similar in kind to terrestrial eruptions such as the 1886 Tarawera eruption. The morphologic evidence for an early phase of explosive activity on Mars is briefly reviewed, and a model is presented for the emplacement of ash-flow deposits on Martian volcanoes. The volcanoes Alba Patera and Olympus Mons are considered in this context, along with some of the older Martian tholi and paterae

  11. 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

  12. 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.

  13. Geology of Kilauea volcano

    SciTech Connect

    Moore, R.B. . Federal Center); Trusdell, F.A. . Hawaiian Volcano Observatory)

    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, 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. 71 refs., 2 figs.

  14. 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

  15. Volcano evolution on Mars

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, Pete; Wilson, Lionel

    1987-01-01

    The diversity of volcanic activity on Mars throughout geologic time was one of the major factors that has controlled the spatial distribution of surface mineralogies. The traditional view of Martian volcanism is one in which effusive activity has dominated the entire preserved geologic history of the planet, with the minor exception of phreatomagnetic activity and associated volcano ground-ice interactions. However, two lines of evidence have caused reconsidering of this view, and have led to the possible role of explosive volcanism on Mars. First, detailed analysis of high resolution Viking Orbiter images has provided good evidence for explosive activity on Hecates Tholus and Alba Patera. Secondly, the problems believed to exist in associating explosive volcanism with silicic magmas on Mars, and the consequent unusual magmatic evolutionary trend for Martian volcanoes from silica-rich to silica-poor, may now be circumvented by the consideration of basatic plinian activity similar in kind to terrestrial eruptions such as the 1886 Tarawera eruption. The morphologic evidence for an early phase of explosive activity on Mars is briefly reviewed, and a model is presented for the emplacement of ash-flow deposits on Martian volcanoes. The volcanoes Alba Patera and Olympus Mons are considered in this context, along with some of the older Martian tholi and paterae

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. Alaska - Russian Far East connection in volcano research and monitoring

    NASA Astrophysics Data System (ADS)

    Izbekov, P. E.; Eichelberger, J. C.; Gordeev, E.; Neal, C. A.; Chebrov, V. N.; Girina, O. A.; Demyanchuk, Y. V.; Rybin, A. V.

    2012-12-01

    The Kurile-Kamchatka-Alaska portion of the Pacific Rim of Fire spans for nearly 5400 km. It includes more than 80 active volcanoes and averages 4-6 eruptions per year. Resulting ash clouds travel for hundreds to thousands of kilometers defying political borders. To mitigate volcano hazard to aviation and local communities, the Alaska Volcano Observatory (AVO) and the Institute of Volcanology and Seismology (IVS), in partnership with the Kamchatkan Branch of the Geophysical Survey of the Russian Academy of Sciences (KBGS), have established a collaborative program with three integrated components: (1) volcano monitoring with rapid information exchange, (2) cooperation in research projects at active volcanoes, and (3) volcanological field schools for students and young scientists. Cooperation in volcano monitoring includes dissemination of daily information on the state of volcanic activity in neighboring regions, satellite and visual data exchange, as well as sharing expertise and technologies between AVO and the Kamchatkan Volcanic Eruption Response Team (KVERT) and Sakhalin Volcanic Eruption Response Team (SVERT). Collaboration in scientific research is best illustrated by involvement of AVO, IVS, and KBGS faculty and graduate students in mutual international studies. One of the most recent examples is the NSF-funded Partnerships for International Research and Education (PIRE)-Kamchatka project focusing on multi-disciplinary study of Bezymianny volcano in Kamchatka. This international project is one of many that have been initiated as a direct result of a bi-annual series of meetings known as Japan-Kamchatka-Alaska Subduction Processes (JKASP) workshops that we organize together with colleagues from Hokkaido University, Japan. The most recent JKASP meeting was held in August 2011 in Petropavlovsk-Kamchatsky and brought together more than 130 scientists and students from Russia, Japan, and the United States. The key educational component of our collaborative program

  4. 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

  5. Rearming Japan

    DTIC Science & Technology

    2007-11-02

    roughly ~’ Ibid., pp. 14-16, 27-30. 12 3.5 percent of their GDP towards defense while Japan spends slightly over 1 percent. Yet, when compared with...runs up huge trade surpluses in its commerce with the United States and Western Europe. Conversely, Japan spends just slightly over one percent of...its GNP on defense indicating to many in the U.S. and Western Europe that Japan is enjoying a free ride and waxing rich under American military

  6. Using thermal remanent magnetisation (TRM) to distinguish block and ash flow and debris flow deposits, and to estimate their emplacement temperature: 1991-1995 lava dome eruption at Mt. Unzen Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Uehara, D.; Cas, R. A. F.; Folkes, C.; Takarada, S.; Oda, H.; Porreca, M.

    2015-09-01

    The 1991-1995 Mt. Unzen eruption (Kyushu, Japan) produced 13 lava domes, approximately 9400 block and ash pyroclastic flows (BAF) resulting from lava dome collapse events and syn- and post-dome collapse debris flow (DF) events. In the field, it can be very difficult to distinguish from field facies characteristics which deposits are primary hot BAF, cold BAF or rock avalanche, or secondary DF deposits. In this study we use a combination of field observations and thermal remanent magnetisation (TRM) analysis of juvenile, lava dome derived clasts from seven deposits of the 1991-1995 Mt. Unzen eruption in order to distinguish between primary BAF deposits and secondary DF deposits and to determine their emplacement temperature. Four major TRM patterns were identified: (1) Type I: clasts with a single magnetic component oriented parallel to the Earth's magnetic field at time and site of emplacement. This indicates that these deposits were deposited at very high temperature, between the Curie temperature of magnetite (~ 540 °C) and the glass transition temperature of the lava dome (~ 745 °C). These clasts are found in high temperature BAF deposits. (2) Type II: clasts with two magnetic components of magnetisation. The lower temperature magnetic components are parallel to the Earth's magnetic field at time of the Unzen eruption. Temperature estimations for these deposits can range from 80 to 540 °C. We found this paleomagnetic behaviour in moderate temperature BAF or warm DF deposits. (3) Type III: clasts with three magnetic components, with a lower temperature component oriented parallel to the Earth's magnetic field at Unzen. The individual clast temperatures estimated for this kind of deposit are usually less than 300 °C. We interpret this paleomagnetic behaviour as the effect of different thermal events during their emplacement history. There are several interpretations for this paleomagnetic behaviour including remobilisation of moderate temperature BAF, warm DF

  7. Geochemical fingerprint of the primary magma composition in the marine tephras originated from the Baegdusan and Ulleung volcanoes

    NASA Astrophysics Data System (ADS)

    Lim, Chungwan; Kim, Seonyoung; Lee, Changyeol

    2014-12-01

    The intraplate Baegdusan (Changbai) and Ulleung volcanoes located on the border of China, North Korea, and East/Japan Sea, respectively, have been explained by appeals to both hotspots and asthenospheric mantle upwelling (wet plume) caused by the stagnant Pacific plate. To understand the origin of the Baegdusan and Ulleung volcanism, we performed geochemical analyses on the tephra deposits in the East/Japan Sea basins originating from the Baegdusan and Ulleung volcanoes. The volcanic glass in the tephra from the Baegdusan and Ulleung volcanoes ranged from alkaline trachyte to peralkaline rhyolite and from phonolite to trachyte, respectively. The tephra from the two intraplate volcanoes showed highly enriched incompatible elements, such as Tb, Nb, Hf, and Ta, distinct from those of the ordinary arc volcanoes of the Japanese islands. The straddle distribution of the Th/Yb and Ta/Yb ratios of the tephra deposits from the Baegdusan volcano may originate from the alkali basaltic magma resulting from mixing between the wet plume from the stagnant Pacific plate in the transition zone and the overlying shallow asthenospheric mantle. In contrast, the deposits from the Ulleung volcano show a minor contribution of the stagnant slab to the basaltic magma, implying either partial melting of a more enriched mantle, smaller degrees of partial melting of a garnet-bearing mantle source, or a combination of both processes as the magma genesis. Our study indicated that the Baegdusan and Ulleung volcanoes have different magma sources and evolutionary histories.

  8. Catalogue of Icelandic volcanoes

    NASA Astrophysics Data System (ADS)

    Ilyinskaya, Evgenia; Larsen, Gudrun; Vogfjörd, Kristin; Tumi Gudmundsson, Magnus; Jonsson, Trausti; Oddsson, Björn; Reynisson, Vidir; Barsotti, Sara; Karlsdottir, Sigrun

    2015-04-01

    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. In the last 100 years, over 30 eruptions have occurred displaying very varied activity in terms of eruption styles, eruptive environments, eruptive products and their distribution. 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 scientific papers and other publications. In 2010, the International Civil Aviation Organisation 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. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland (commenced in 2012), and the EU FP7 project FUTUREVOLC (2012-2016), establishing an Icelandic volcano Supersite. The Catalogue is a collaborative effort between the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Icelandic Civil Protection, with contributions from a large number of specialists in Iceland and elsewhere. The catalogue is scheduled for opening in the first half of 2015 and once completed, it will be an official publication intended to serve as an accurate and up to date source of information about active volcanoes in Iceland and their characteristics. The Catalogue is an open web resource in English and is composed of individual chapters on each of the volcanic systems. The chapters include information on the geology and structure of the volcano; the eruption history, pattern and products; the known precursory signals

  9. 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.

  10. Japan Report.

    DTIC Science & Technology

    1985-05-01

    Industry , says the exhibition of about 70,000 foreign products mainly agricultural goods, household appliances, liquor, confectionaries , industrial ...Fishery Talks Restart (KYODO, 13 Apr 85) 38 Forest Products Industry To Get Government Aid (KYODO, 25 Mar 85) 39 China Asked To Curb Cotton...Customs-Cleared Trade 66 USSR-Japan Fishery Talks 66 Auto Exports 66 Japan, Malaysia Air Service 66 Trade Friction 67 Strategic Aid 67 Trade

  11. 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.

  12. Small Syrian Volcano

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-498, 29 September 2003

    Today, 29 September 2003, is the first day of southern summer, and the first day of northern winter on Mars. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small volcano in Syria Planum near 12.9oS, 102.7oW. The volcano and surrounding terrain have been thickly mantled by dust; this dust has subsequently been eroded so that it appears textured rather than smooth. The thin, light streaks that crisscross the image are the tracks left by passing dust devils. Not all dust devils on Mars make streaks, and not all streaks are darker than their surroundings--those found in Syria Planum are invariably lighter in tone. The picture covers an area 3 km (1.9 mi) across; sunlight illuminates the scene from the upper left.

  13. Anatahan Volcano, Mariana Islands

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In the early hours of February 7, ASTER captured this nighttime thermal infrared image of an eruption of Anatahan Volcano in the central Mariana Islands. The summit of the volcano is bright indicating there is a very hot area there. Streaming to the west is an ash plume, visible by the red color indicating the presence of silicate-rich particles. Dark grey areas are clouds that appear colder than the ocean. Anatahan is a stratovolcano that started erupting in May 2003, forming a new crater.

    The image covers an area of 56.3 x 41.8 km, and is located 16 degrees north latitude and 145.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  14. Development of volcano monitoring technique using repeating earthquakes observed by the Volcano Observation Network of NIED

    NASA Astrophysics Data System (ADS)

    Kohno, Y.; Ueda, H.; Kimura, H.; Nagai, M.; Miyagi, Y.; Fujita, E.; Kozono, T.; Tanada, T.

    2012-12-01

    After the Grate East Japan Earthquake (M9.0) on March 11, 2011, the M6.4 earthquake occurred beneath Mt. Fuji on March 15, 2011. Although the hypocenter seemed to be very close to an assumed magma chamber of Fuji volcano, no anomalies in volcanic activity have been observed until August 2012. As an example, after the M6.1 earthquake occurred in 1998 at southwest of Iwate volcano, a change of seismic velocity structure (e.g. Nishimura et al., 2000) was observed as well as active seismicity and crustal deformation. It had affected waveforms of repeating earthquakes occurring at a plate subduction zone, that is, the waveform similarities were reduced just after the earthquake due to upwelling of magma. In this study, first we analyzed for Mt. Fuji where such changes are expected by the occurrence of the earthquake to try to develop a tool for monitoring active volcanoes using the Volcano Observation network (V-net) data. We used seismic waveform data of repeating earthquakes observed by short period seismometers of V-net and the High Sensitivity Seismograph Network Japan (Hi-net) stations near Fuji volcano after 2007. The seismic data were recorded with a sampling rate of 100 Hz, and we applied 4-8 Hz band pass filter to reduce noise. The repeating earthquakes occurred at the plate subduction zone and their catalog is compiled by Hi-net data (Kimura et al., 2006). We extracted repeating earthquake groups that include earthquakes before and after the M6.4 earthquake on March 15, 2011. A waveform of the first event of the group and waveforms of the other events are compared and calculated cross-correlation coefficients. We adjusted P wave arrivals of each event and calculate the coefficients and lag times of the latter part of the seismic waves with the time window of 1.25 s. We searched the best fit maximizing the cross-correlation coefficients with 0.1 s shift time at each time window. As a result we found three remarkable points at this time. [1] Comparing lag times

  15. Hydrolytic conversion of AsO(-3)4 to HAsO(-2)4: a QMCF MD study.

    PubMed

    Bhattacharjee, Anirban; Hofer, Thomas S; Pribil, Andreas B; Randolf, Bernhard R; Rode, Bernd M

    2010-06-21

    A quantum mechanical charge field molecular dynamics (QMCF MD) study of AsO in water was carried out to gain insight into its conversion from the hydrated anion resulting in OH(-) ions and HAsO, which occurs on the scale of a few hundred femtoseconds. The OH(-) ion undergoes further proton exchange with water molecules, while HAsO is a stable species.

  16. Experimental and theoretical characterization of arsenite in water: insights into the coordination environment of As-O.

    PubMed

    Ramírez-Solís, Alejandro; Mukopadhyay, Rita; Rosen, Barry P; Stemmler, Timothy L

    2004-05-03

    Long-term exposure to arsenic in drinking water has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate in humans. It is therefore important to understand the structural aspects of arsenic in water, as hydrated arsenic is most likely the initial form of the metalloid absorbed by cells. We present a detailed experimental and theoretical characterization of the coordination environment of hydrated arsenite. XANES analysis confirms As(III) is a stable redox form of the metalloid in solution. EXAFS analysis indicate, at neutral pH, arsenite has a nearest-neighbor coordination geometry of approximately 3 As-O bonds at an average bond length of 1.77 A, while at basic pH the nearest-neighbor coordination geometry shifts to a single short As-O bond at 1.69 A and two longer As-O bonds at 1.82 A. Long-range ligand scattering is present in all EXAFS samples; however, these data could not be fit with any degree of certainty. There is no XAS detectable interaction between As and antimony, suggesting they are not imported into cells as a multinuclear complex. XAS results were compared to a structural database of arsenite compounds to confirm that a 3 coordinate As-O complex for hydrated arsenite is the predominate species in solution. Finally, quantum chemical studies indicate arsenite in solution is solvated by 3 water molecules. These results indicate As(OH)3 as the most stable structure existing in solution at neutral pH; thus, ionic As transport does not appear to be involved in the cellular uptake process.

  17. 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.

  18. Ice Volcanoes and Topography

    NASA Image and Video Library

    2015-11-10

    Scientists using New Horizons images of Pluto's surface to make 3-D topographic maps have discovered that two of Pluto's mountains, informally named Wright Mons and Piccard Mons, could possibly be ice volcanoes. The color is shown to depict changes in elevation, with blue indicating lower terrain and brown showing higher elevation; green terrains are at intermediate heights. http://photojournal.jpl.nasa.gov/catalog/PIA20050

  19. 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

  20. 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.

  1. 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.

  2. Volcanoes generate devastating waves

    SciTech Connect

    Lockridge, P. )

    1988-01-01

    Although volcanic eruptions can cause many frightening phenomena, it is often the power of the sea that causes many volcano-related deaths. This destruction comes from tsunamis (huge volcano-generated waves). Roughly one-fourth of the deaths occurring during volcanic eruptions have been the result of tsunamis. Moreover, a tsunami can transmit the volcano's energy to areas well outside the reach of the eruption itself. Some historic records are reviewed. Refined historical data are increasingly useful in predicting future events. The U.S. National Geophysical Data Center/World Data Center A for Solid Earth Geophysics has developed data bases to further tsunami research. These sets of data include marigrams (tide gage records), a wave-damage slide set, digital source data, descriptive material, and a tsunami wall map. A digital file contains information on methods of tsunami generation, location, and magnitude of generating earthquakes, tsunami size, event validity, and references. The data can be used to describe areas mot likely to generate tsunamis and the locations along shores that experience amplified effects from tsunamis.

  3. 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.

  4. 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.

  5. 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.

  6. Disposition and Pharmacology of a GalNAc3-conjugated ASO Targeting Human Lipoprotein (a) in Mice

    PubMed Central

    Yu, Rosie Z; Graham, Mark J; Post, Noah; Riney, Stan; Zanardi, Thomas; Hall, Shannon; Burkey, Jennifer; Shemesh, Colby S; Prakash, Thazha P; Seth, Punit P; Swayze, Eric E; Geary, Richard S; Wang, Yanfeng; Henry, Scott

    2016-01-01

    Triantennary N-acetyl galactosamine (GalNAc3)-conjugated antisense oligonucleotides (ASOs) have greatly improved potency via receptor-mediated uptake. In the present study, the in vivo pharmacology of a 2′-O-(2-methoxyethyl)-modified ASO conjugated with GalNAc3 (ISIS 681257) together with its unmodified congener (ISIS 494372) targeting human apolipoprotein (a) (apo(a)), were studied in human LPA transgenic mice. Further, the disposition kinetics of ISIS 681257 was studied in CD-1 mice. ISIS 681257 demonstrated over 20-fold improvement in potency over ISIS 494372 as measured by liver apo(a) mRNA and plasma apo(a) protein levels. Following subcutaneous (SC) dosing, ISIS 681257 cleared rapidly from plasma and distributed to tissues. Intact ISIS 681257 was the major full-length oligonucleotide species in plasma. In tissues, however, GalNAc sugar moiety was rapidly metabolized and unconjugated ISIS 681257 accounted > 97% of the total exposure, which was then cleared slowly from tissues with a half-life of 7–8 days, similar to the half-life in plasma. ISIS 681257 is highly bound to plasma proteins (> 94% bound), which limited its urinary excretion. This study confirmed dose-dependent exposure to the parent drug ISIS 681257 in plasma and rapid conversion to unconjugated ASO in tissues. Safety data and the extended half-life support its further development and weekly dosing in phase 1 clinical studies. PMID:27138177

  7. K2[HCr2AsO10]: redetermination of phase II and the predicted structure of phase I.

    PubMed

    Weakley, T J R; Ylvisaker, E R; Yager, R J; Wu, P; Photinos, P; Abrahams, S C

    2004-12-01

    Our prediction that phase II of dipotassium hydrogen chromatoarsenate, K(2)[HCr(2)AsO(10)], is ferroelectric, based on the analysis of the atomic coordinates by Averbuch-Pouchot, Durif & Guitel [Acta Cryst. (1978), B34, 3725-3727], led to an independent redetermination of the structure using two separate crystals. The resulting improved accuracy allows the inference that the H atom is located in the hydrogen bonds of length 2.555 (5) angstroms which form between the terminal O atoms of shared AsO(3)OH tetrahedra in adjacent HCr(2)AsO(10)(2-) ions. The largest atomic displacement of 0.586 angstroms between phase II and the predicted paraelectric phase I is by these two O atoms. The H atoms form helices of radius approximately 0.60 A about the 3(1) or 3(2) axes. Normal probability analysis reveals systematic error in seven or more of the earlier atomic coordinates.

  8. Monitoring volcano threats from space

    USGS Publications Warehouse

    Duda, Kenneth A.; Wessels, Rick L.; Ramsey, Michael; Dehn, Jonathan

    2007-01-01

    Volcanoes can have extremely wide ranging effects. Even a single eruption can cause disastrous climate changes at great distance from the source. Thus, it is important to have a system to monitor even the most remote volcanoes. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra spacecraft and other satellite sensors provide imagery that is critical to the global volcano monitoring solution.

  9. Researchers discuss Mt. Unzen, a decade volcano

    NASA Astrophysics Data System (ADS)

    Nakada, Setsuya; Eichelberger, John; Shimizu, Hiroshi

    In November 1989, a swarm of earthquakes deep beneath Tachibana Bay, Kyushu Island, Japan, heralded the inexorable rise of magma toward the summit of Unzen Volcano, some 15 km upward and 15 km eastward, on the Shimabara Peninsula. When the “magma head” emerged in Jigokuato Crater on May 20, 1991, a beautiful but tragic drama began. It started peacefully as a budding flower unfolding lava petals (Figure 1). But by the time lava stopped flowing in February 1995, it had cost the city of Shimabara and the surrounding towns over $2 billion in damage and 44 human lives. At its height, the crisis required the prolonged evacuation of 11,000 residents. Amid this tragedy, however, volcanologists were able to make unprecedented visual and geophysical observations of processes of magma ascent, dome growth, and dome-fed pyroclastic flows.

  10. Volcanic Lightning in Eruptions of Sakurajima Volcano

    NASA Astrophysics Data System (ADS)

    Edens, Harald; Thomas, Ronald; Behnke, Sonja; McNutt, Stephen; Smith, Cassandra; Farrell, Alexandra; Van Eaton, Alexa; Cimarelli, Corrado; Cigala, Valeria; Eack, Ken; Aulich, Graydon; Michel, Christopher; Miki, Daisuke; Iguchi, Masato

    2016-04-01

    In May 2015 a field program was undertaken to study volcanic lightning at the Sakurajima volcano in southern Japan. One of the main goals of the study was to gain a better understanding of small electrical discharges in volcanic eruptions, expanding on our earlier studies of volcanic lightning at Augustine and Redoubt volcanoes in Alaska, USA, and Eyjafjallajökull in Iceland. In typical volcanic eruptions, electrical activity occurs at the onset of an eruption as a near-continual production of VHF emissions at or near to the volcanic vent. These emissions can occur at rates of up to tens of thousands of emissions per second, and are referred to as continuous RF. As the ash cloud expands, small-scale lightning flashes of several hundred meters length begin to occur while the continuous RF ceases. Later on during the eruption larger-scale lightning flashes may occur within the ash cloud that are reminiscent of regular atmospheric lightning. Whereas volcanic lightning flashes are readily observed and reasonably well understood, the nature and morphology of the events producing continuous RF are unknown. During the 2015 field program we deployed a comprehensive set of instrumentation, including a 10-station 3-D Lightning Mapping Array (LMA) that operated in 10 μs high time resolution mode, slow and fast ΔE antennas, a VHF flat-plate antenna operating in the 20-80 MHz band, log-RF waveforms within the 60-66 MHz band, an infra-red video camera, a high-sensitivity Watec video camera, two high-speed video cameras, and still cameras. We give an overview of the Sakurajima field program and present preliminary results using correlated LMA, waveforms, photographs and video recordings of volcanic lightning at Sakurajima volcano.

  11. Mechanical coupling between earthquakes, volcanos and landslides

    NASA Astrophysics Data System (ADS)

    Feigl, K. L.; Retina Team

    2003-04-01

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

  12. Multinational seismic investigation focuses on Rabaul volcano

    NASA Astrophysics Data System (ADS)

    Gudmundsson, O.; Johnson, R. W.; Finlayson, D. M.; Nishimura, Y.; Shimamura, H.; Terashima, A.; Itikarai, I.; Thurber, C.

    An improved disaster-reduction strategy for civil authorities and communities on the Gazelle Peninsula in Papua New Guinea is anticipated as a result of a multinational seismic investigation now under way there. Data collection has been completed but interpretation is at a preliminary stage. Volcanic eruptions in 1994 devastated the town of Rabaul and other communities on the peninsula.The investigation, known as the Rabaul Earthquake Location and Caldera Structure (RELACS) program, is building a seismic tomography image of the Rabaul volcano that will improve the precision with which volcano-related earthquakes can be located in real time. This will enable the Rabaul Volcanological Observatory (RVO) to interpret seismicity patterns in detail and provide better advice to civil authorities. Among other things, the scientific analytical capacity of RVO will be upgraded by improving knowledge about the subsurface structure of the caldera. Conducting the work are scientists from the Australian Geological Survey Organisation (AGSO), the Australian National University (ANU), the University of Hokkaido in Japan, and the University of Wisconsin (UW) in the United States.

  13. Volcanic hazard map for Telica, Cerro Negro and El Hoyo volcanoes, Nicaragua

    NASA Astrophysics Data System (ADS)

    Asahina, T.; Navarro, M.; Strauch, W.

    2007-05-01

    A volcano hazard study was conducted for Telica, Cerro Negro and El Hoyo volcanoes, Nicaragua, based on geological and volcanological field investigations, air photo analyses, and numerical eruption simulation. These volcanoes are among the most active volcanoes of the country. This study was realized 2004-2006 through technical cooperation of Japan International Cooperation Agency (JICA) with INETER, upon the request of the Government of Nicaragua. The resulting volcanic hazard map on 1:50,000 scale displays the hazards of lava flow, pyroclastic flows, lahars, tephra fall, volcanic bombs for an area of 1,300 square kilometers. The map and corresponding GIS coverage was handed out to Central, Departmental and Municipal authorities for their use and is included in a National GIS on Georisks developed and maintained by INETER.

  14. Volcanic and geologic database projects of the Geological Survey of Japan (Invited)

    NASA Astrophysics Data System (ADS)

    Takarada, S.; Nakano, S.; Hoshizumi, H.; Itoh, J.; Urai, M.; Nishiki, K.

    2009-12-01

    Geological Survey of Japan (GSJ) is presently implementing the GEO-DB project, which aims to integrate all kinds of geological information in GSJ. GSJ published more than 50 CD-ROM series and established more than 20 databases at the Research Information Database (RIO-DB) of the National Institute of Advanced Industrial Science and Technology (AIST). Presently, four volcanic databases are open to the public: (1) Quaternary volcano database (RIO-DB), (2) Active volcano database (RIO-DB), and (3) ASTER satellite image database of major volcanoes. The Quaternary volcano database contains information such as volcanic type, history, age and pictures of more than 300 Quaternary volcanoes in Japan. More detailed volcanic information will be added to the database in the near future. The active volcano database contains information of active volcanoes in Japan such as the catalog of eruptive events during the last 10,000 years and geological maps of active volcanoes. The ASTER satellite image database provides sequential ASTER satellite image datasets of major volcanoes in the world. Collaboration between Quaternary and active volcano databases and the VOGRIPA project is the next important activity at the Geological Survey of Japan. The Geological Survey of Japan introduced the Integrated Geological Map Database (GeoMapDB) in 2006. The GeoMapDB is based on a WebGIS technology, which makes it possible to browse, overlay and search geological maps online. The database contains geological maps with scales ranging from 1:2 million to 1:25,000. Links to aforementioned volcanic database and active fault database in RIO-DB are also available. OneGeology is an international initiative of the geological surveys of the world and a flagship project of the ‘International Year of Planet Earth’. It aims to create dynamic geological map of the world available at the world wide web. Geological Surveys from 109 countries of the world are participating in this project. The Geological

  15. Radar Image, Hokkaido, Japan

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The southeast part of the island of Hokkaido, Japan, is an area dominated by volcanoes and volcanic caldera. The active Usu Volcano is at the lower right edge of the circular Lake Toya-Ko and near the center of the image. The prominent cone above and to the left of the lake is Yotei Volcano with its summit crater. The city of Sapporo lies at the base of the mountains at the top of the image and the town of Yoichi -- the hometown of SRTM astronaut Mamoru Mohri -- is at the upper left edge. The bay of Uchiura-Wan takes up the lower center of the image. In this image, color represents elevation, from blue at the lowest elevations to white at the highest. The radar image has been overlaid to provide more details of the terrain. Due to a processing problem, an island in the center of this crater lake is missing and will be properly placed when further SRTM swaths are processed. The horizontal banding in this image is a processing artifact that will be removed when the navigation information collected by SRTM is fully calibrated. 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-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC. Size: 100 by 150 kilometers

  16. 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

  17. 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.

  18. Japan Report.

    DTIC Science & Technology

    2007-11-02

    apprehensions of Europe and America that China would become closely related with Japan alone and that Japan might monopolize the Chinese market . As a...out of the 300 billion yen, 100 billion yen is supplier’s credit from concerted action by the Ex-Im Bank and the Open Market Bank, 130 billion yen is...to launch production in the U.S. in the belief that Japanese automakers will have to continue some form of export restraints for the American market

  19. Eruption of Shiveluch Volcano, Kamchatka, Russia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On the night of June 4, 2001 ASTER captured this thermal image of the erupting Shiveluch volcano. Located on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 8028'. The active lava dome complex is seen as a bright (hot) area on the summit of the volcano. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25 km ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred during the last 10,000 years; the largest historical eruptions were in 1854 and 1964. Because Kamchatka is located along the major aircraft routes between North America/Europe and the Far East, this area is constantly monitored for potential ash hazards to aircraft. The lower image is the same as the upper, except it has been color coded: red is hot, light greens to dark green are progressively colder, and gray/black are the coldest areas.

    The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

    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, Calif., 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 ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in

  20. Eruption of Shiveluch Volcano, Kamchatka, Russia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On the night of June 4, 2001 ASTER captured this thermal image of the erupting Shiveluch volcano. Located on Russia's Kamchatka Peninsula, Shiveluch rises to an altitude of 8028'. The active lava dome complex is seen as a bright (hot) area on the summit of the volcano. To the southwest, a second hot area is either a debris avalanche or hot ash deposit. Trailing to the west is a 25 km ash plume, seen as a cold 'cloud' streaming from the summit. At least 60 large eruptions have occurred during the last 10,000 years; the largest historical eruptions were in 1854 and 1964. Because Kamchatka is located along the major aircraft routes between North America/Europe and the Far East, this area is constantly monitored for potential ash hazards to aircraft. The lower image is the same as the upper, except it has been color coded: red is hot, light greens to dark green are progressively colder, and gray/black are the coldest areas.

    The image is located at 56.7 degrees north latitude, 161.3 degrees east longitude.

    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, Calif., 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 ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in

  1. Remote sensing of Italian volcanos

    NASA Technical Reports Server (NTRS)

    Bianchi, R.; Casacchia, R.; Coradini, A.; Duncan, A. M.; Guest, J. E.; Kahle, A.; Lanciano, P.; Pieri, D. C.; Poscolieri, M.

    1990-01-01

    The results of a July 1986 remote sensing campaign of Italian volcanoes are reviewed. The equipment and techniques used to acquire the data are described and the results obtained for Campi Flegrei and Mount Etna are reviewed and evaluated for their usefulness for the study of active and recently active volcanoes.

  2. Changing volcanoes on Io

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Volcanoes on Jupiter's moon Io are compared in these images from NASA's Galileo spacecraft (right) taken in early September of this year, and from the Voyager spacecraft (left) taken in 1979. Prometheus (bright ring in upper right) was first seen as an erupting volcano by the Voyager spacecraft and still features an active plume. A smaller active plume was discovered at the volcano Culann Patera (dark feature at lower left) by the Galileo spacecraft.

    Prometheus has displayed similar characteristics such as size, shape and brightness to Galileo's cameras as it did to Voyager's. However, several intriguing differences are also apparent. There appears to be a new dark lava flow emanating from the vent of Prometheus, and the plume is now erupting from a position about 75 kilometers (46.5 miles) west from where the hot spot resided in 1979. It is not known if the plume source is the same or if the plume is now emanating from a new source. Overall, scientists studying Galileo images of Io see that a wide variety of surface changes have occurred on Io since 1979. The Galileo image was taken at a range of about 487,000 kilometers (about 302,000 miles) from Io. The Voyager image was taken from about 800,000 kilometers (about 500,000 miles).

    The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo

  3. Italian Volcano Supersites

    NASA Astrophysics Data System (ADS)

    Puglisi, G.

    2011-12-01

    Volcanic eruptions are among the geohazards that may have a substantial economic and social impact, even at worldwide scale. Large populated regions are prone to volcanic hazards worldwide. Even local phenomena may affect largely populated areas and in some cases even megacities, producing severe economic losses. On a regional or global perspective, large volcanic eruptions may affect the climate for years with potentially huge economic impacts, but even relatively small eruptions may inject large amounts of volcanic ash in the atmosphere and severely affect air traffic over entire continents. One of main challenges of the volcanological community is to continuously monitor and understand the internal processes leading to an eruption, in order to give substantial contributions to the risk reduction. Italian active volcanoes constitute natural laboratories and ideal sites where to apply the cutting-edge volcano observation systems, implement new monitoring systems and to test and improve the most advanced models and methods for investigate the volcanic processes. That's because of the long tradition of volcanological studies resulting into long-term data sets, both in-situ and from satellite systems, among the most complete and accurate worldwide, and the large spectrum of the threatening volcanic phenomena producing high local/regional/continental risks. This contribution aims at presenting the compound monitoring systems operating on the Italian active volcanoes, the main improvements achieved during the recent studies direct toward volcanic hazard forecast and risk reductions and the guidelines for a wide coordinated project aimed at applying the ideas of the GEO Supersites Initiative at Mt. Etna and Campi Flegrei / Vesuvius areas.

  4. Volcanoes, Central Java, Indonesia

    NASA Image and Video Library

    1992-08-08

    The island of Java (8.0S, 112.0E), perhaps better than any other, illustrates the volcanic origin of Pacific Island groups. Seen in this single view are at least a dozen once active volcano craters. Alignment of the craters even defines the linear fault line of Java as well as the other some 1500 islands of the Indonesian Archipelago. Deep blue water of the Indian Ocean to the south contrasts to the sediment laden waters of the Java Sea to the north.

  5. Ijen Volcano, Indonesia

    NASA Image and Video Library

    2017-07-14

    West of Gunung Merapi, East Java, Indonesia, is the Ijen volcano, which has a one-kilometer-wide turquoise-colored acidic crater lake. The lake is the site of a labor-intensive sulfur mining operation, in which sulfur-laden baskets are carried by hand from the crater floor. The lake is recognized as the largest highly acidic crater lake in the world, with a pH of 0.5. The image was acquired 17 September 2008, covers an area of 24 by 39 kilometers, and is located at 8 degrees south, 114.2 degrees east. https://photojournal.jpl.nasa.gov/catalog/PIA21787

  6. Volcanoes, Central Java, Indonesia

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The island of Java (8.0S, 112.0E), perhaps better than any other, illustrates the volcanic origin of Pacific Island groups. Seen in this single view are at least a dozen once active volcano craters. Alignment of the craters even defines the linear fault line of Java as well as the other some 1500 islands of the Indonesian Archipelago. Deep blue water of the Indian Ocean to the south contrasts to the sediment laden waters of the Java Sea to the north.

  7. Ruiz Volcano: Preliminary report

    NASA Astrophysics Data System (ADS)

    Ruiz Volcano, Colombia (4.88°N, 75.32°W). All times are local (= GMT -5 hours).An explosive eruption on November 13, 1985, melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than 20,000 people. This is history's fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000), and Mount Pelée in May 1902 (28,000). The following briefly summarizes the very preliminary and inevitably conflicting information that had been received by press time.

  8. 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

  9. Volcano deformation and subdaily GPS products

    NASA Astrophysics Data System (ADS)

    Grapenthin, Ronni

    Volcanic unrest is often accompanied by hours to months of deformation of the ground that is measurable with high-precision GPS. Although GPS receivers are capable of near continuous operation, positions are generally estimated for daily intervals, which I use to infer characteristics of a volcano’s plumbing system. However, GPS based volcano geodesy will not be useful in early warning scenarios unless positions are estimated at high rates and in real time. Visualization and analysis of dynamic and static deformation during the 2011 Tohokuoki earthquake in Japan motivates the application of high-rate GPS from a GPS seismology perspective. I give examples of dynamic seismic signals and their evolution to the final static offset in 30 s and 1 s intervals, which demonstrates the enhancement of subtle rupture dynamics through increased temporal resolution. This stresses the importance of processing data at recording intervals to minimize signal loss. Deformation during the 2009 eruption of Redoubt Volcano, Alaska, suggested net deflation by 0.05 km³ in three distinct phases. Mid-crustal aseismic precursory inflation began in May 2008 and was detected by a single continuous GPS station about 28 km NE of Redoubt. Deflation during the explosive and effusive phases was sourced from a vertical ellipsoidal reservoir at about 7-11.5 km. From this I infer a model for the temporal evolution of a complex plumbing system of at least 2 sources during the eruption. Using subdaily GPS positioning solutions I demonstrate that plumes can be detected and localized by utilizing information on phase residuals. The GPS network at Bezymianny Volcano, Kamchatka, records network wide subsidence at rapid rates between 8 and 12 mm/yr from 2005-2010. I hypothesize this to be caused by continuous deflation of a ˜30 km deep sill under Kluchevskoy Volcano. Interestingly, 1-2 explosive events per year cause little to no deformation at any site other than the summit site closest to the vent. I

  10. Volcanic Activities of Hakkoda Volcano after the 2011 Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Miura, S.

    2014-12-01

    The 2011 Tohoku Earthquake of 11 March 2011 generated large deformation in and around the Japanese islands, and the large crustal deformation raises fear of further disasters including triggered volcanic activities. In this presentation, as an example of such potential triggered volcanic activities, we report the recent seismic activities of Hakkoda volcano, and discuss the relation to the movement of volcanic fluids. Hakkoda volcano is a group of stratovolcanoes at the northern end of Honshu Island, Japan. There are fumaroles and hot springs around the volcano, and phreatic eruptions from Jigoku-numa on the southwestern flank of Odake volcano, which is the highest peak of the volcanic group, were documented in its history. Since just after the occurrence of the Tohokui Earthquake, the seismicity around the volcano became higher, and the migration of hypocenters of volcano-tectonic (VT) earthquakes was observed.In addition to these VT earthquakes, long-period (LP) events started occurring beneath Odake at a depth of about 2-3 km since February, 2013, and subtle crustal deformation caused by deep inflation source was also detected by the GEONET GNSS network around the same time. The spectra of LP events are common between events irrespective of the magnitude of events, and they have several spectral peaks at 6-7 sec, 2-3 sec, 1 sec, and so on. These LP events sometimes occur like a swarm with an interval of several minutes. The characteristics of observed LP events at Hakkoda volcano are similar to those of LP events at other active volcanoes and hydrothermal area in the world, where abundant fluids exist. Our further analysis using far-field Rayleigh radiation pattern observed by NIED Hi-net stations reveals that the source of LP events is most likely to be a nearly vertical tensile crack whose strike is NE-SW direction. The strike is almost perpendicular to the direction of maximum extensional strain estimated from the geodetic analysis, and is almost parallel to

  11. Monitoring Mount Baker Volcano

    USGS Publications Warehouse

    Malone, S.D.; Frank, D.

    1976-01-01

    Hisotrically active volcanoes in the conterminous United States are restricted to the Cascade Range and extend to the Cascade Range and extend from Mount Baker near the Canadian border to Lassen Peak in northern California. Since 1800 A.D, most eruptive activity has been on a relatively small scale and has not caused loss of life or significant property damage. However, future  volcanism predictably will have more serious effects because of greatly increased use of land near volcanoes during the present century. (See "Appraising Volcanic Hazards of the Cascade Range of the Northwestern United States," Earthquake Inf. Bull., Sept.-Oct. 1974.) The recognition an impending eruption is highly important in order to minimize the potential hazard to people and property. Thus, a substantial increase in hydrothermal activity at Mount Baker in March 1975 ( see "Mount Baker Heating Up," July-Aug. 1975 issue) was regarded as a possible first signal that an eruption might occur, and an intensive monitoring program was undertaken. 

  12. Sulfur Volcanoes on Io?

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Fink, J.

    1985-01-01

    The unusual rheological properties of molten sulfur, in which viscosity decreases approximately four orders of magnitude as it cools from 170 to 120 C, may result in distinctive volcanic flow morphologies that allow sulfur flows and volcanoes to be identified on Io. Search of high resolution Voyager images reveals three features--Atar Patera, Daedalus Patera, and Kibero Patera--considered to be possible sulfur volcanoes based on their morphology. All three average 250 km in diameter and are distinguished by circular-to-oval central masses surrounded by irregular, widespread flows. Geometric relations indicate that the flows were emplaced after the central zone and appear to have emanated from their margins. The central zones are interpreted to be domes representing the high temperature stage of sulfur formed initially upon eruption. Rapid quenching formed a crust which preserved this phase of the emplacement. Upon cooling to 170 C, the sulfur reached a low viscosity runny stage and was released as the thin, widespread flows.

  13. 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

  14. 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.

  15. 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

  16. The evolution of young silicic lavas at Medicine Lake Volcano, California: Implications for the origin of compositional gaps in calc-alkaline series lavas

    USGS Publications Warehouse

    Grove, T.L.; Donnelly-Nolan, J. M.

    1986-01-01

    gap). At Mt. Mazama and Mt. St. Helens, USA and Aso Caldera and Shikotsu, Japan the amphibole-bearing assemblage was important. At Krakatau, Indonesia and Katmai, USA, an augite+orthopyroxene-bearing assemblage was important. In addition to its role in the production of a compositional gap between intermediate and rhyolitic lavas, the crystallization process increases the H2O content of the residual liquid. This rapid increase in residual liquid volatile content which results from the precipitation of a large proportion of crystalline solids may be an important factor among several that lead to explosive silicic eruptions. ?? 1986 Springer-Verlag.

  17. 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.

  18. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. )

    1991-04-01

    In-plane stresses, which accompany the flexural deformation of the lithosphere under the load 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.

  19. 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.

  20. Eruptive viscosity and volcano morphology

    NASA Technical Reports Server (NTRS)

    Posin, Seth B.; Greeley, Ronald

    1988-01-01

    Terrestrial central volcanoes formed predominantly from lava flows were classified as shields, stratovolcanoes, and domes. Shield volcanoes tend to be large in areal extent, have convex slopes, and are characterized by their resemblance to inverted hellenic war shields. Stratovolcanoes have concave slopes, whereas domes are smaller and have gentle convex slopes near the vent that increase near the perimeter. In addition to these differences in morphology, several other variations were observed. The most important is composition: shield volcanoes tend to be basaltic, stratovolcanoes tend to be andesitic, and domes tend to be dacitic. However, important exceptions include Fuji, Pico, Mayon, Izalco, and Fuego which have stratovolcano morphologies but are composed of basaltic lavas. Similarly, Ribkwo is a Kenyan shield volcano composed of trachyte and Suswa and Kilombe are shields composed of phonolite. These exceptions indicate that eruptive conditions, rather than composition, may be the primary factors that determine volcano morphology. The objective of this study is to determine the relationships, if any, between eruptive conditions (viscosity, erupted volume, and effusion rate) and effusive volcano morphology. Moreover, it is the goal of this study to incorporate these relationships into a model to predict the eruptive conditions of extraterrestrial (Martian) volcanoes based on their morphology.

  1. Mount Rainier active cascade volcano

    NASA Astrophysics Data System (ADS)

    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.

  2. Source Inversions of Volcano Infrasound: Mass Outflux and Force System for Transient Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Kim, K.; Fee, D.; Lees, J. M.; Yokoo, A.; Ruiz, M. C.

    2014-12-01

    Sources of volcano infrasound associated with explosive eruptions are typically modeled assuming an acoustic monopole and/or dipole. While the monopole represents the mass outflux of erupted materials, the dipole represents a force system acting in the source region during eruptions. Therefore, appropriate acoustic source inversions of volcano infrasound data can provide estimates of eruption parameters which are critical to understanding eruption dynamics. Reliability of the source parameters is dominantly controlled by the accuracy of the acoustic Green's functions between the source and receiver positions. Conventional source inversions of volcano infrasound, however, were typically performed using a simplified Green's function obtained in a free space or half space. This may result in intolerable errors in the source parameters, especially when the infrasound waveforms are significantly distorted by volcano topography and/or local atmospheric variability (i.e., layered velocity structure or wind). In this study we present a full waveform inversion technique for volcano infrasound using numerical Green's functions. A full 3-D Finite-Difference Time-Domain (FDTD) method accelerated with GPU is used to compute accurate Green's functions taking into account volcano topography and local atmospheric conditions. The presented method is applied to data recorded at Sakurajima volcano (Japan) and Tungurahua volcano (Ecuador), which provide a large volume of high-quality data recorded by azimuthally well-distributed stations within 2 -- 6 km distance of the volcanoes. We analyze infrasound signals associated with explosive eruptions exhibiting 1) distinct explosion waveforms followed by gas discharges and 2) strong anisotropic radiation patterns, which can be caused by either source directivity or topographic barriers/reflections. Here the role of topography in controlling the infrasound radiation is investigated through numerical modeling, and then the observed

  3. Activity at Shiveluch Volcano

    NASA Image and Video Library

    2017-09-27

    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

  4. Counterfactual Volcano Hazard Analysis

    NASA Astrophysics Data System (ADS)

    Woo, Gordon

    2013-04-01

    , if a major storm surge happens to arrive at a high astronomical tide, sea walls may be overtopped and flooding may ensue. In the domain of geological hazards, periods of volcanic unrest may generate precursory signals suggestive of imminent volcanic danger, but without leading to an actual eruption. Near-miss unrest periods provide vital evidence for assessing the dynamics of volcanoes close to eruption. Where the volcano catalogue has been diligently revised to include the maximum amount of information on the phenomenology of unrest periods, dynamic modelling and hazard assessment may be significantly refined. This is illustrated with some topical volcano hazard examples, including Montserrat and Santorini.

  5. Groundwater at Mayon, Volcano

    NASA Astrophysics Data System (ADS)

    Albano, S. E.; Sandoval, T.; Toledo, R.

    2001-12-01

    Around Mayon Volcano, Philippines, anecdotal evidence and rainfall normalized spring discharge data suggest that the water table 8 km from the summit of the volcano drops prior to eruptions. Residents report that they had to deepen their shallow wells in 1993 (some before and others following the eruption). In some cases they had to dig as far as 5 meters deeper to reach the water table. Significant decreases in spring discharge were recorded prior to the 1999 phreatic explosions and explosive eruption in 2000. A lesser decrease in spring discharge was recorded prior to the 2001 explosive eruptions. The cause of the observed correlation is not yet understood. Mechanisms consider include decrease in rainfall and boiling away of groundwater due to magmatic intrusion. Dilatation of the volcano may cause an increase in pore pressure, opening of cracks, and inflation of the ground surface that would all result in lower water table levels and decreases in spring discharges. Lack of significant hydraulic precursors prior to the 2001 eruptions may be due to a sustained state of inflation following the eruption of 2000. To better understand the relationship between changes in the volcanic system and changes in the groundwater system surrounding Mayon, instruments were installed about eight kilometers from the summit immediately following the explosive eruption of 26 July 2001. Parameters monitored include rainfall data, water levels in four shallow wells, discharge in the main river basin, and spring discharge. The aquifers at eight kilometers are predominantly poorly sorted lahar flow deposits. Characterization of these highly permeable aquifers has been conducted. Preliminary data include porosity ranges, hydraulic conductivity estimates, and response to rainfall. Water samples have been collected that are intended for geo-chemical analysis to determine if the water is predominantly meteoric or magmatic in origin. Numerical modeling of the system using the above mentioned

  6. Crystal growth and crystal structures of six novel phases in the Mn/As/O/Cl(Br) system, as well as magnetic properties of α-Mn3(AsO4)2

    NASA Astrophysics Data System (ADS)

    Weil, Matthias; Kremer, Reinhard K.

    2017-01-01

    Chemical vapour transport reactions (900 °C → 820 °C, Cl2 or Br2 as transport agent) of in situ formed Mn3(AsO4)2 yielded the orthoarsenates(V) α-Mn3(AsO4)2 and β-Mn3(AsO4)2 as well as the oxoarsenate(V) halide compounds Mn7(AsO4)4Cl2, Mn11(AsO4)7Cl, Mn11(AsO4)7Br and Mn5(AsO4)3Cl. The crystal structures of all six phases were determined from single crystal X-ray diffraction data. The crystal structures of α-and β-Mn3(AsO4)2 are isotypic with the corresponding phosphate phases γ- and α-Mn3(PO4)2, respectively, and are reported here for the first time. A comparative discussion with other structures of general composition M3(AsO4)2 (М = Mg; divalent first-row transition metal) is given. The unique crystal structures of Mn7(AsO4)4Cl2 and that of the two isotypic Mn11(AsO4)7X (X = Cl, Br) structures are composed of two [MnO5] polyhedra, two [MnO4Cl2] polyhedra (one with site symmetry 1 bar), two AsO4 tetrahedra, and one [MnO5] polyhedron, three [MnO6] octahedra (one with site symmetry.m.), one [MnO4X], one [MnO5X] polyhedron and four AsO4 tetrahedra, respectively. The various polyhedra of the three arsenate(V) halides are condensed into three-dimensional framework structures by corner- and edge-sharing. Mn5(AsO4)3Cl adopts the chloroapatite structure. The magnetic and thermal properties of pure polycrystalline samples of a-Mn3(AsO4)2 were investigated in more detail. The magnetic susceptibility proves all Mn atoms to be in the oxidation state +2 yielding an effective magnetic moment per Mn atom of 5.9 μB. Long-range antiferromagnetic ordering is observed below 8.2 K consistent with the negative Curie-Weiss temperature of -50 K derived from the high temperature susceptibility data. Chemical vapour transport reactions of in situ formed Mn3(AsO4)2 using Cl2 or Br2 as transport agents led to crystal growth of six phases structurally determined for the first time: α-Mn3(AsO4)2, β-Mn3(AsO4)2, Mn7(AsO4)4Cl2, Mn11(AsO4)7Cl, Mn11(AsO4)7Br and Mn5(AsO4)3Cl.

  7. Japan Report.

    DTIC Science & Technology

    1985-02-19

    Bonds 57 Australian Tianium Contract 53 Grants to Mongolia 50 Light-Controlling Glass 58 Host Computer Models 53 New Cancer-Heating Device 53 - b...6 million yen vli) Development studies: increase from 252 to 281 studies: measures to pre- vent desertification (150 million yen); measures for...Tokyo KYODO in English 0357 GMT 25 Jan 85 OW] GRANTS TO MONGOLIA —Tokyo, 25 Jan (KYODO)—Japan will extend grants totaling 16 million yen (63,000 dollars

  8. Japan Report.

    DTIC Science & Technology

    1985-03-14

    bring exchange rates to a more reasonable level. Prime Minister Nakasone told the Diet Wednesday his government intends to make its utmost efforts to... make the Japanese market more accessible to imports. He suggested stepped up capital exports as one way to whittle down Japan’s huge trade surplus...confirming the agreement. In Bangladesh, shallow wells and rivers are the main supply sources of drinkable water . The Bangladesh Government has

  9. Japan Report.

    DTIC Science & Technology

    2007-11-02

    KYODO, 23 Apr 85)........ 58 PRC Ensuring Ability To Pay for Imports (KYODO, 7 May 85) 59 OECD Official Interviewed on Trade Surplus...Security Council session, claiming the council has failed to denounce Iraq for using chemical weapons against Iran. De Cuellar and Japanese officials...infarction, a loss of blood supply to the brain , and would require two or three months to recover. Tanaka is regarded as Japan’s most powerful

  10. Japan Report.

    DTIC Science & Technology

    2007-11-02

    prayer at the Yasukuni Shinto Shrine in downtown Tokyo, which is dedicated to Japan’s many war dead. The visit, on the occasion of the shrine’s...Visits Yasukini Shrine for War Dead (KYODO, 22 Apr 85) 4 Atlantic Institute Holds Heated Security Debate (KYODO, 19 Apr 85) 5 Disaster...between him and Kakuei Tanaka. 12930 CSO: 4105/198 JPRS-JAR-85-014 24 May 1985 POLITICAL AND SOCIOLOGICAL NAKASONE VISITS YASUKINI SHRINE FOR

  11. Okinawa, Japan

    NASA Image and Video Library

    1991-08-11

    The southern half of the island of Okinawa, Japan (26.5N, 128.0E) can be seen in this nearly cloud free view. Okinawa is part of the Ryuku Islands which extend from Taiwan northeastward to Kyushu, southernmost of the Japanese Home Islands. The large military base at Kadena, with large runways, is visible near the center of the scene. Kadena is one of several emergency landing sites around the world for the space shuttle.

  12. Japan Report

    DTIC Science & Technology

    1985-03-18

    the government should reduce expenditures for military hardware if it is difficult to hold defense spending within 1 percent of the GNP. Noting... expenditure , as well as a greater contribution to Pacific defense . According to Prior, a conservative parliamentarian and former secretary of state for...Northern Ireland, with Britain’s experience in Asia, it should join with Japan to help the United States with its Asian defense . Japanese Chairman

  13. 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.

  14. Monitoring active volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1987-01-01

    One of the most spectacular, awesomely beautiful, and at times destructive displays of natural energy is an erupting volcano, belching fume and ash thousands of meters into the atmosphere and pouring out red-hot molten lava in fountains and streams. Countless eruptions in the geologic past have produced volcanic rocks that form much of the Earth's present surface. The gradual disintegration and weathering of these rocks have yielded some of the richest farmlands in the world, and these fertile soils play a significant role in sustaining our large and growing population. Were it not for volcanic activity, the Hawaiian Islands with their sugar cane and pineapple fields and magnificent landscapes and seascapes would not exist to support their residents and to charm their visitors. Yet, the actual eruptive processes are catastrophic and can claim life and property.

  15. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  16. Living with volcanoes

    USGS Publications Warehouse

    Wright, Thomas L.; Pierson, Thomas C.

    1992-01-01

    The 1980 cataclysmic eruption of Mount St. Helens (Lipman and Mullineaux, 1981) in southwestern Washington ushered in a decade marked by more worldwide volcanic disasters and crises than any other in recorded history. Volcanoes killed more people (over 28,500) in the 1980's than during the 78 years following 1902 eruption of Mount Pelee (Martinique). Not surprisingly, volcanic phenomena and attendant hazards received attention from government authorities, the news media, and the general public. As part of this enhanced global awareness of volcanic hazards, the U.S. Geological Survey (Bailey and others, 1983) in response to the eruptions or volcanic unrest during the 1980's at Mount St. Helens and Redoubt are still erupting intermittently, and the caldera unrest at Long Valley also continues, albeit less energetically than during the early 1980's.

  17. A Diminutive Volcano

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 15 October 2003

    The small Tharsis volcano called Biblis Patera is nearly lost amongst its gigantic neighbors. With a height of less than 10,000 feet, it is even dwarfed by many volcanoes on Earth. The gaping caldera of Biblis Patera shows evidence for multiple episodes of collapse, producing the concentric topography seen in the image. Several slope streaks are visible, indicators of a more recent and much smaller form of collapse: avalanches of the dust that thickly mantles the terrain.

    Image information: VIS instrument. Latitude 2.3, Longitude 236.4 East (123.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Chiliques Volcano, Chile

    NASA Image and Video Library

    2002-04-19

    A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24, 2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen. The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA03493

  19. Slab melting as an explanation of Quaternary volcanism and aseismicity in southwest Japan

    NASA Astrophysics Data System (ADS)

    Morris, Paul A.

    1995-05-01

    Two volcanoes on the Quaternary volcanic front in southwest Japan have erupted medium-K andesite and dacite, which are chemically similar to adakites (i.e., high Al2O3, Sr/Y, low Y, and steep rare earth element [REE] patterns with no negative Eu anomalies), unlike other subduction-related volcanoes in Japan. Earthquake data and the extrapolated position of the Philippine Sea plate from its near-trench position indicate that the leading edge of the plate is ˜75 100 km deep beneath these volcanoes. Melting of the plate at this depth would leave a garnet eclogite residual, accounting for the Y and heavy REE depletion. The lack of seismic data and active volcanism in southwest Japan can be attributed to the attenuated seismic response of the plate due to melting and to the atypical nature of magma generation.

  20. Flank tectonics of Martian volcanoes

    NASA Technical Reports Server (NTRS)

    Thomas, Paul J.; Squyres, Steven W.; Carr, Michael H.

    1990-01-01

    The origin of the numerous terraces on the flanks of the Olympus Mons volcano on Mars, seen on space images to be arranged in a roughly concentric pattern, is investigated. The images of the volcano show that the base of each terrace is marked by a modest but abrupt change in slope, suggesting that these terraces could be thrust faults caused by a compressional failure of the cone. The mechanism of faulting and the possible effect of the interior structure of Olympus Mons was investigated using a numerical model for elastic stresses within a Martian volcano, constructed for that purpose. Results of the analysis supports the view that the terraces on Olympus Mons, as well as on other three Martian volcanoes, including Ascraeus Mons, Arsia Mons, and Pavonis Mons are indeed thrust faults.

  1. 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.

  2. 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.

  3. Layers in Arsia Mons Volcano

    NASA Image and Video Library

    2010-10-28

    This observance from NASA Mars Reconnaissance Orbiter covers a pit in the lower West flank of Arsia Mons, one of the four giant volcanos of the Tharsis region. Many layers are exposed in the pit, probably marking individual lava flows.

  4. Venus - Volcanos in Guinevere Planitia

    NASA Image and Video Library

    1996-03-14

    This image from NASA Magellan spacecraft, with radar illumination from west to east, shows three unusual volcanoes located in the Guinevere Planitia lowland. http://photojournal.jpl.nasa.gov/catalog/PIA00261

  5. Lateral variation of H2O contents in Quaternary Magma of central Northeastern Japan arc

    NASA Astrophysics Data System (ADS)

    Miyagi, I.; Matsu'ura, T.; Itoh, J.; Morishita, Y.

    2011-12-01

    Water plays a key role in the genesis and eruptive mechanisms of subduction zone volcanoes. We estimated bulk rock water content of both frontal and back arc volcanoes from Northeastern Japan arc in order to understand the lateral variation of magmatic H2O contents in the island arc magma. Our analytical targets are the Adachi volcano located near the volcanic front and the Hijiori volcano located on back arc side. In this study, the bulk magmatic H2O content is estimated by a simple mass balance calculation of the chemistry of bulk rock and melt inclusions in phenocrysts; the melt H2O contents of melt inclusions analyzed by SIMS or EPMA are corrected according to the difference in K2O content between melt inclusions and bulk rock. The bulk magmatic H2O we obtained is 8 wt. % or even more for Adachi and is 2-3 wt. % for Hijiori. Thus, the frontal volcano has higher H2O than the back arc volcano. Although our data are opposed to the previous estimation on the lateral variation of H2O contents in Quaternary volcanoes of Northeastern Japan arc (e.g., Sakuyama, 1979), thermodynamic computations using MELTS (Ghiorso and Sack, 1995) suggest that the amount of bulk magmatic H2O we estimated is consistent with petrographical observations. Our data imply a regional characteristics in the type of eruption that the H2O rich frontal volcanoes will erupt explosively and those H2O poor back arc ones will be effusive, which implication is consistent with actual geological observations that volcanoes located on back arc side of the Northeastern Japan arc generally comprise lava flow (e.g., Iwaki, Kanpu, Chokai, Gassan), in contrast to the frontal ones that produced voluminous tephra (e.g., Osorezan, Towada, Narugo, Adachi). This research project has been conducted under the research contract with Nuclear and Industrial Safety Agency (NISA).

  6. Redetermination of eveite, Mn2AsO4(OH), based on single-crystal X-ray diffraction data

    PubMed Central

    Yang, Yongbo W.; Stevenson, Ryan A.; Siegel, Alesha M.; Downs, Gordon W.

    2011-01-01

    The crystal structure of eveite, ideally Mn2(AsO4)(OH) [dimanganese(II) arsenate(V) hydroxide], was refined from a single crystal selected from a co-type sample from Långban, Filipstad, Varmland, Sweden. Eveite, dimorphic with sarkinite, is structurally analogous with the important rock-forming mineral andalusite, Al2OSiO4, and belongs to the libethenite group. Its structure consists of chains of edge-sharing distorted [MnO4(OH)2] octa­hedra (..2 symmetry) extending parallel to [001]. These chains are cross-linked by isolated AsO4 tetra­hedra (..m symmetry) through corner-sharing, forming channels in which dimers of edge-sharing [MnO4(OH)] trigonal bipyramids (..m symmetry) are located. In contrast to the previous refinement from Weissenberg photographic data [Moore & Smyth (1968 ▶). Am. Mineral. 53, 1841–1845], all non-H atoms were refined with anisotropic displacement param­eters and the H atom was located. The distance of the donor and acceptor O atoms involved in hydrogen bonding is in agreement with Raman spectroscopic data. Examination of the Raman spectra for arsenate minerals in the libethenite group reveals that the position of the peak originating from the O—H stretching vibration shifts to lower wavenumbers from eveite, to adamite, zincolivenite, and olivenite. PMID:22199466

  7. Wyllieite-type Ag1.09Mn3.46(AsO4)3

    PubMed Central

    Frigui, Wafa; Zid, Mohamed Faouzi; Driss, Ahmed

    2012-01-01

    Single crystals of wyllieite-type silver(I) manganese(II) tris­orthoarsenate(V), Ag1.09Mn3.46(AsO4)3, were grown by a solid-state reaction. The three-dimensional framework is made up from four Mn2+/Mn3+ cations surrounded octa­hedrally by O atoms. The MnO6 octa­hedra are linked through edge- and corner-sharing. Three independent AsO4 tetra­hedra are linked to the framework through common corners, delimiting channels along [100] in which two partly occupied Ag+ sites reside, one on an inversion centre and with an occupancy of 0.631 (4), the other on a general site and with an occupancy of 0.774 (3), both within distorted tetra­hedral environments. One of the Mn sites is also located on an inversion centre and is partly occupied, with an occupancy of 0.916 (5). Related compounds with alluaudite-type or rosemaryite-type structures are compared and discussed. PMID:22719272

  8. Na3Co2(AsO4)(As2O7): a new sodium cobalt arsenate

    PubMed Central

    Guesmi, Abderrahmen; Driss, Ahmed

    2012-01-01

    In the title compound, tris­odium dicobalt arsenate diarsenate, Na3Co2AsO4As2O7, the two Co atoms, one of the two As and three of the seven O atoms lie on special positions, with site symmetries 2 and m for the Co, m for the As, and 2 and twice m for the O atoms. The two Na atoms are disordered over two general and special positions [occupancies 0.72 (3):0.28 (3) and 0.940 (6):0.060 (6), respectively]. The main structural feature is the association of the CoO6 octa­hedra in the ab plane, forming Co4O20 units, which are corner- and edge-connected via AsO4 and As2O7 arsenate groups, giving rise to a complex polyhedral connectivity with small tunnels, such as those running along the b- and c-axis directions, in which the Na+ ions reside. The structural model is validated by both bond-valence-sum and charge-distribution methods, and the distortion of the coordination polyhedra is analyzed by means of the effective coordination number. PMID:22807699

  9. Remote triggering of seismicity at Japanese volcanoes following the 2016 M7.3 Kumamoto earthquake

    NASA Astrophysics Data System (ADS)

    Enescu, Bogdan; Shimojo, Kengo; Opris, Anca; Yagi, Yuji

    2016-10-01

    The MJMA7.3 Kumamoto earthquake occurred on April 16, 2016, in the western part of Kyushu, at a depth of 12 km, on an active strike-slip fault. Here, we report on a relatively widespread activation of small remote earthquakes, which occurred as far as Hokkaido, detected by analyzing the continuous waveform data recorded at seismic stations all over Japan. Such relatively widespread remote seismicity activation, following a large inland earthquake, has not been reported before for Japan. Our analysis demonstrates that the remote events were triggered dynamically, by the passage of the surface waves from the Kumamoto earthquake. Most of the remotely triggered events in the Tohoku and Hokkaido regions, as well as close to Izu Peninsula, occur at or close to volcanoes, which suggests that the excitation of crustal fluids, by the passage of Rayleigh waves, played an important triggering role. Nevertheless, remote activation in other regions, like Noto Peninsula, occurred away from volcanoes. The relatively large-amplitude Love waves, enhanced by a source directivity effect during the Kumamoto earthquake, may have triggered seismicity on local active faults. The dynamic stresses in the areas where remote activation has been observed range from several kPa to tens of kPa, the thresholds being lower than in previous dynamic triggering cases for Japan; this might relate to a change in the crustal conditions following the 2011 M9.0 Tohoku-oki earthquake, in particular at volcanoes in NE Japan.[Figure not available: see fulltext.

  10. Resistivity Changes of Sakurajima Volcano by Magnetotelluric Continuous Observations

    NASA Astrophysics Data System (ADS)

    Aizawa, K.; Kanda, W.; Ogawa, Y.; Iguchi, M.; Yokoo, A.

    2009-12-01

    In order to predict volcano eruptions and to contribute to hazard mitigation, monitoring of subsurface magma movement is the most essential approach. Recent study of time change of seismic structure (4D tomography) in Etna volcano clearly imaged time change of Vp/Vs structure, [Patanè et al., 2006]. They showed that structure changes not only on the location of magma intrusion but widely around the intrusion. They attributed Vp/Vs change to subsurface magma movement and fluids migration from the intrusion zone. Another method using seismic noise records are proposed to monitor the subsurface seismic structure [Brenguier et al., 2008]. These seismic methods have a great potential to reliable prediction of volcano eruption, though the method need densely deployed seismometer network. Monitoring electric resistivity structure is also the promising tools for imaging the subsurface magma movement, because magma and degassed volatile is highly conductive. Indeed, by repeated DC electric measurement using active source field, significant resistivity change is detected before and after the 1986 eruption of Izu-Oshima volcano, and the subsurface magma movement is deduced [Yukutake et al., 1990; Utada, 2003]. In this study, we show the first results of the long term continuous magnetotellurics (MT) observation to monitor the resistivity structure. Because MT impedance is stable and high time resolution [Eisel and Egbert, 2001; Hanekop and Simpson, 2006], the continuous MT observation is suitable to detect subsurface resistivity changes. We conducted long-term MT continuous measurements since May, 2008 to July, 2009 at Sakurajima, which is the most active volcano in Japan. Two observation sites were set up at 3.3km east, and 3km WNW of the summit crater. The obtained MT impedance shows significant apparent resistivity changes, which continues 20~50 days, in the frequency range between 300-1 Hz at the both observation sites. This frequency range corresponds to the depth

  11. Mahukona: The missing Hawaiian volcano

    SciTech Connect

    Garcia, M.O.; Muenow, D.W. ); Kurz, M.D. )

    1990-11-01

    New bathymetric and geochemical data indicate that a seamount west of the island of Hawaii, Mahukona, is a Hawaiian shield volcano. Mahukona has weakly alkalic lavas that are geochemically distinct. They have high {sup 3}He/{sup 4}He ratios (12-21 times atmosphere), and high H{sub 2}O and Cl contents, which are indicative of the early state of development of Hawaiian volcanoes. The He and Sr isotopic values for Mahukona lavas are intermediate between those for lavas from Loihi and Manuna Loa volcanoes and may be indicative of a temporal evolution of Hawaiian magmas. Mahukona volcano became extinct at about 500 ka, perhaps before reaching sea level. It fills the previously assumed gap in the parallel chains of volcanoes forming the southern segment of the Hawaiian hotspot chain. The paired sequence of volcanoes was probably caused by the bifurcation of the Hawaiian mantle plume during its ascent, creating two primary areas of melting 30 to 40 km apart that have persisted for at least the past 4 m.y.

  12. Mount St. Helens and Kilauea volcanoes

    SciTech Connect

    Barrat, J. )

    1989-01-01

    Mount St. Helens' eruption has taught geologists invaluable lessons about how volcanoes work. Such information will be crucial in saving lives and property when other dormant volcanoes in the northwestern United States--and around the world--reawaken, as geologists predict they someday will. Since 1912, scientists at the U.S. Geological Survey's Hawaiian Volcano Observatory have pioneered the study of volcanoes through work on Mauna Loa and Kilauea volcanoes on the island of Hawaii. In Vancouver, Wash., scientists at the Survey's Cascades Volcano Observatory are studying the after-effects of Mount St. Helens' catalysmic eruption as well as monitoring a number of other now-dormant volcanoes in the western United States. This paper briefly reviews the similarities and differences between the Hawaiian and Washington volcanoes and what these volcanoes are teaching the volcanologists.

  13. Deformations of a small mud volcano revealed by multi-temporal terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Hayakawa, Yuichi S.; Kusumoto, Shigekazu; Matta, Nobuhisa

    2017-04-01

    Activities of mud volcanoes are often regarded as signals of tectonics both in subaerial and submarine environments. Characteristics of mud volcanoes, including the composition of mud, water and gas, the underground structure, and the surface morphology, have often been investigated to reveal their activities. Here we explore the spatial variation in the deformation of a small terrestrial mud volcano, which has hardly been revealed without the use of high-resolution topographic measurements. The Murono mud volcano (north-central Japan) exhibits displacements of its ground surface morphology both by the earthquake events and in the inter-seismic quiescent periods. Multiple-time terrestrial laser scanning (TLS) was applied to detect the spatial variations in the ground surface deformations. After registering the point cloud data at different times using numerous points on unchanged reference features, deformations of the central zone of the mud volcano were detected at the scale of centimeters to decimeters, including both central uplift and peripheral subsidence with an elliptic spatial pattern. Open cracks on the central uplift area were also mapped, whose formation was successfully modeled with the displacement and stress fields estimated by the strong earthquakes. More gradual changes in the surface elevation of the mud volcano during the inter-seismic quiescent periods were also detected by the TLS data, and it was revealed that the spatial location of the center of uplift could have changed after an earthquake event.

  14. Coexistence of magnetic fluctuations and superconductivity in SmFe0.95Co0.05AsO seen in 57Fe Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Long, G.; Demarco, M.; Chudyk, M.; Steiner, J.; Coffey, D.; Zeng, H.; Li, Y. K.; Cao, G. H.; Xu, Z. A.

    2011-08-01

    The Mössbauer spectra (MS) of powder samples of SmFe1-xCoxAsO (x = 0.0, 0.05, and 0.1) were measured in applied fields up to 9 T and at temperatures up to 298 K. SmFeAsO is magnetically ordered with TN = 137 K and has a hyperfine magnetic field of (4.98 ± 0.18) T at 4.2 K. In applied magnetic fields, the MS is consistent with a distribution of hyperfine magnetic fields of width Happlied+Hhyperfine. This arises because the angles between the direction of the ordered field in the crystallites making up the sample are randomly distributed about the direction of the applied field. The MS of the superconductors SmFe0.95Co0.05AsO (TC≃5 K) and SmFe0.9Co0.1AsO (TC≃17 K) are well described by a single peak from room temperature to 4.2 K indicating the absence of static magnetic order. However, the half width at half maximum, Γ, of the peak in SmFe0.95Co0.05AsO increases with decreasing temperature from its high temperature value, 0.13 mm/s at 25 K, to 0.25 mm/s at 10 K. No such temperature dependence is seen in SmFe0.9Co0.1AsO. We analyze this temperature dependence in terms of a fluctuating hyperfine magnetic field model whose frequency at 4.2 K is found to be ˜5-10 MHz, giving direct evidence of coexisting magnetic fluctuations and superconductivity at the interface in the phase diagram between the regions with magnetic and superconducting order. In a 5 T applied field, SmFe0.95Co0.05AsO is no longer superconducting; however, the temperature-dependent fluctuating magnetic field is still present and largely unchanged. The absence of fluctuations in superconducting SmFe0.9Co0.1AsO and their presence in superconducting SmFe0.95Co0.05AsO in zero applied field and in nonsuperconducting SmFe0.95Co0.05AsO at 5 T suggests that magnetic order is in competition with superconductivity in SmFe1-xCoxAsO.

  15. High-throughput investigation in the synthesis of the alluaudite-type manganese arsenate: AgMn 3(AsO 4)(HAsO 4) 2

    NASA Astrophysics Data System (ADS)

    Stock, N.; Bein, T.

    2003-09-01

    The application of high-throughput methods under hydrothermal conditions in the investigation of the system AgNO 3/Mn(NO 3) 2/H 3AsO 4 has led to the new manganese arsenate AgMn 3(AsO 4)(HAsO 4) 2 which is structurally related to the mineral alluaudite. It crystallizes in the monoclinic space group C2/ c with a=12.397(2), b=12.707(2), c=6.8904(6) Å, β=113.57(1)°, V=994.8(2) Å 3, Z=4, R1=0.021, wR2=0.046.

  16. 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

  17. Imaging of multi-geophysical parameters in the 2016 Kumamoto earthquake (MJ7.3) in Kyushu of southwest Japan

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Fukao, Y.

    2016-12-01

    Seismic waveform study reveals where the rupture began and how it expanded for the 2016 Kumamoto earthquake. We here focus on the investigation of the rupture initiation and their interactions of the earthquake generating and volcanic magmatism. To address these issues, detailed 3D seismic velocity and Poisson's ratio images are determined using 368,340 P-wave and S-wave source-receiver pairs from 6,018 aftershocks and 6,114 background earthquakes. We also estimated the crack density, saturate fracture and bulk-sound velocity under the Kumamoto source and its nearby volcanoes from the inverted seismic models. Our study offers geophysical evidence for that the Kumamoto earthquake was more likely to be triggered by the fluids penetration ascending from the Unzen volcanic magma which intrudes into the Futagawa and Hinagu fault zones. Such a fluids intrusion would decrease Vp and Vs whilst increase Poisson's ratio and saturate fracture in the seismogenic layer, and then lead to high pore pressure there. The multiple geophysical parameter imaging indicate that a strong low-velocity zone with high crack density and high saturate fracture, extending into the 2016 Kumamoto hypocenter, is imaged in the Unzen volcano. This suggests that the mechanical strength in the hypocenter could be vulnerability compared with the normal seismogenic layer, whilst the pore pressure of the fluids in the hypocenter could be high due to fluids accumulation. Our study implies closely relationship between the Unzen volcanic magmatism and the Kumamoto earthquake generation. On the contrary, high-velocity and low-Poisson's ratio zone is clearly imaged under the Aso volcano with low-crack density and low-saturate fracture anomalies in the upper crust. This contrasted feature underneath the Unzen and Aso volcanoes suggests the inequable contributions to earthquake generating and different interactions of the earthquake generating and volcanic magmatism.

  18. Pyroclastic Flow Remnants at Shiveluch Volcano

    NASA Image and Video Library

    2017-09-27

    NASA image acquired February 25, 2011 Pyroclastic flows are some of the most fearsome hazards posed by erupting volcanoes. These avalanches of superheated ash, gas, and rock are responsible for some of the most famous volcanic disasters in history, including the burial of the ancient Roman city of Pompei and the destruction of Saint-Pierre in 1902. More recently, pyroclastic flows from Mount Merapi in Indonesia caused most of the casualties during the volcano’s 2010 eruption. The intense heat—over 1,000° Celsius (1800° Fahrenheit)—the terrific speed—up to 720 kilometers (450 miles) per hour—and the mixture of toxic gases all contribute to the deadly potential. Pyroclastic flows can incinerate, burn, or asphyxiate people who cannot get out of the flow path. This false-color satellite image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite shows the remnants of a large pyroclastic flow on the slopes of Shiveluch Volcano. Fortunately, no one was hurt during the eruption and flow in the sparsely-populated area. ASTER detected heat from the flow during or shortly after an event on January 25, 2011. Note how the heat signatures from January line up with the dark surface deposits visible on February 25; those deposits cover more than 10 square kilometers (4 square miles). Light brown ash covers the snow above the flow deposits, and a tiny plume rises from Shiveluch’s growing lava dome. Vegetation surrounding the volcano is colored dark red. 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. Instrument: Terra - ASTER Credit: NASA Earth Observatory 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

  19. Multibeam Bathymetry of Haleakala Volcano, Maui

    NASA Astrophysics Data System (ADS)

    Eakins, B. W.; Robinson, J.

    2002-12-01

    The submarine northeast flank of Haleakala Volcano, Maui was mapped in detail during the summers of 2001 and 2002 by a joint team from the Japan Marine Science and Technology Center (JAMSTEC), Tokyo Institute of Technology, University of Hawaii, and the U.S. Geological Survey. JAMSTEC instruments used included SeaBeam 2112 hull-mounted multibeam sonar (bathymetry and sidescan imagery), manned submersible Shinkai 6500 and ROV Kaiko (bottom video, photographs and sampling of Hana Ridge), gravimeter, magnetometer, and single-channel seismic system. Hana Ridge, Haleakala's submarine east rift zone, is capped by coral-reef terraces for much of its length, which are flexurally tilted towards the axis of the Hawaiian Ridge and delineate former shorelines. Its deeper, more distal portion exhibits a pair of parallel, linear crests, studded with volcanic cones, that suggest lateral migration of the rift zone during its growth. The northern face of the arcuate ridge terminus is a landslide scar in one of these crests, while its southwestern prong is a small, constructional ridge. The Hana slump, a series of basins and ridges analogous to the Laupahoehoe slump off Kohala Volcano, Hawaii, lies north of Hana Ridge and extends down to the Hawaiian moat. Northwest of this slump region a small, dual-crested ridge strikes toward the Hawaiian moat and is inferred to represent a fossil rift zone, perhaps of East Molokai Volcano. A sediment chute along its southern flank has built a large submarine fan with a staircase of contour-parallel folds on its surface that are probably derived from slow creep of sediments down into the moat. Sediments infill the basins of the Hana slump [Moore et al., 1989], whose lowermost layers have been variously back-tilted by block rotation during slumping and flexural loading of the Hawaiian Ridge; the ridges define the outer edges of those down-dropped blocks, which may have subsided several kilometers. An apron of volcaniclastic debris shed from

  20. "Mediterranean volcanoes vs. chain volcanoes in the Carpathians"

    NASA Astrophysics Data System (ADS)

    Chivarean, Radu

    2017-04-01

    Volcanoes have always represent an attractive subject for students. Europe has a small number of volcanoes and Romania has none active ones. The curricula is poor in the study of volcanoes. We want to make a parallel between the Mediterranean active volcanoes and the old extinct ones in the Oriental Carpathians. We made an comparison of the two regions in what concerns their genesis, space and time distribution, the specific relief and the impact in the landscape, consequences of their activities, etc… The most of the Mediterranean volcanoes are in Italy, in the peninsula in Napoli's area - Vezuviu, Campi Flegrei, Puzzoli, volcanic islands in Tirenian Sea - Ischia, Aeolian Islands, Sicily - Etna and Pantelleria Island. Santorini is located in Aegean Sea - Greece. Between Sicily and Tunisia there are 13 underwater volcanoes. The island called Vulcano, it has an active volcano, and it is the origin of the word. Every volcano in the world is named after this island, just north of Sicily. Vulcano is the southernmost of the 7 main Aeolian Islands, all volcanic in origin, which together form a small island arc. The cause of the volcanoes appears to be a combination of an old subduction event and tectonic fault lines. They can be considered as the origin of the science of volcanology. The volcanism of the Carpathian region is part of the extensive volcanic activity in the Mediterranean and surrounding regions. The Carpathian Neogene/Quaternary volcanic arc is naturally subdivided into six geographically distinct segments: Oas, Gutai, Tibles, Calimani, Gurghiu and Harghita. It is located roughly between the Carpathian thrust-and-fold arc to the east and the Transylvanian Basin to the west. It formed as a result of the convergence between two plate fragments, the Transylvanian micro-plate and the Eurasian plate. Volcanic edifices are typical medium-sized andesitic composite volcanoes, some of them attaining the caldera stage, complicated by submittal or peripheral domes

  1. El Misti Volcano and the City of Arequipa, Peru

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This three-dimensional perspective view was created from an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Model combined with a simulated natural color ASTER image, acquired July 13, 2001. It shows El Misti volcano towering 5822 meters high above the second city of Peru, Arequipa, with a population of more than one million. Geologic studies indicate that El Misti has had five minor eruptions this century, and a major eruption in the 15th century when residents were forced to flee the city. Despite the obvious hazard, civil defense authorities see it as a remote danger, and city planners are not avoiding development on the volcano side of the city. This view shows human development extending up the flanks of the volcano along gullies which would form natural channels for flows of lava, superheated ash and gas, or melted ice, snow, and mud from the summit snowfield in the event of an eruption. Image by Mike Abrams, NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

  2. Satellite monitoring of African volcanoes by means of RSTVOLC

    NASA Astrophysics Data System (ADS)

    Pergola, Nicola; Coviello, Irina; Falconieri, Alfredo; Filizzola, Carolina; Lacava, Teodosio; Liuzzi, Mariangela; Marchese, Francesco; Paciello, Rossana; Tramutoli, Valerio

    2015-04-01

    RSTVOLC is an algorithm for volcanic hot spot detection from space based on the Robust Satellite Techniques (RST) multi-temporal approach. This algorithm was firstly tested on Mt. Etna area, analyzing a long-term time series of infrared Advanced Very High Resolution Radiometer (AVHRR) satellite records, and was then implemented on data provided by the Moderate Resolution Imaging Spectroradiometer (MODIS) to study a number of volcanoes in different geographic areas, including Asamayama (Japan) and Eyjafjallajökull (Iceland). Recently, RSTVOLC has been exported on data provided by geostationary sensors such as the Spinning Enhanced Visible and Infrared Imager (SEVIRI), onboard Meteosat Second Generation (MSG) satellites, allowing for the timely detection and real time monitoring of thermal volcanic phenomena. In this work, recent results achieved studying some important African volcanoes by means of polar and geostationary satellite data are presented. Outcomes and results achieved by RSTVOLC studying some past Ol Donyo Lengai (Tanzania) eruptions and the recent Nyamuragira (Congo) activity are reported and discussed, also for comparison with other independent hot spot detection techniques. This study confirms that RSTVOLC may be successfully used to monitor volcanoes at a global scale and to detect low level thermal activities, thanks to its intrinsic self-adaptivity to different observational/environmental conditions as well as to its high sensitivity to sublte hot spots, contributing to volcanic risk mitigation.

  3. Thermal surveillance of volcanoes

    NASA Technical Reports Server (NTRS)

    Friedman, J. D. (Principal Investigator)

    1972-01-01

    The author has identified the following significant results. A systematic aircraft program to monitor changes in the thermal emission from volcanoes of the Cascade Range has been initiated and is being carried out in conjunction with ERTS-1 thermal surveillance experiments. Night overflights by aircraft equipped with thermal infrared scanners sensitive to terrestrial emission in the 4-5.5 and 8-14 micron bands are currently being carried out at intervals of a few months. Preliminary results confirm that Mount Rainier, Mount Baker, Mount Saint Helens, Mount Shasta, and the Lassen area continue to be thermally active, although with the exception of Lassen which erupted between 1914 and 1917, and Mount Saint Helens which had a series of eruptions between 1831 and 1834, there has been no recent eruptive activity. Excellent quality infrared images recorded over Mount Rainier, as recently as April, 1972, show similar thermal patterns to those reported in 1964-1966. Infrared images of Mount Baker recorded in November 1970 and again in April 1972 revealed a distinct array of anomalies 1000 feet below the crater rim and associated with fumaroles or structures permitting convective heat transfer to the surface.

  4. Sand Volcano Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

  5. Sand Volcano Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

  6. Seismic signals from Lascar Volcano

    NASA Astrophysics Data System (ADS)

    Hellweg, M.

    1999-03-01

    Lascar, the most active volcano in northern Chile, lies near the center of the region studied during the Proyecto de Investigación Sismológica de la Cordillera Occidental 94 (PISCO '94). Its largest historical eruption occurred on 19 April 1993. By the time of the PISCO '94 deployment, its activity consisted mainly of a plume of water vapor and SO 2. In April and May 1994, three short-period, three-component seismometers were placed on the flanks of the volcano, augmenting the broadband seismometer located on the NW flank of the volcano during the entire deployment. In addition to the usual seismic signals recorded at volcanoes, Lascar produced two unique tremor types: Rapid-fire tremor and harmonic tremor. Rapid-fire tremor appears to be a sequence of very similar, but independent, "impulsive" events with a large range of amplitudes. Harmonic tremor, on the other hand, is a continuous, cyclic signal lasting several hours. It is characterized by a spectrum with peaks at a fundamental frequency and its integer multiples. Both types of tremor seem to be generated by movement of fluids in the volcano, most probably water, steam or gas.

  7. Lifespans of Cascade Arc volcanoes

    NASA Astrophysics Data System (ADS)

    Calvert, A. T.

    2015-12-01

    Compiled argon ages reveal inception, eruptive episodes, ages, and durations of Cascade stratovolcanoes and their ancestral predecessors. Geologic mapping and geochronology show that most Cascade volcanoes grew episodically on multiple scales with periods of elevated behavior lasting hundreds of years to ca. 100 kyr. Notable examples include the paleomag-constrained, few-hundred-year-long building of the entire 15-20 km3 Shastina edifice at Mt. Shasta, the 100 kyr-long episode that produced half of Mt. Rainier's output, and the 30 kyr-long episode responsible for all of South and Middle Sister. Despite significant differences in timing and rates of construction, total durations of active and ancestral volcanoes at discrete central-vent locations are similar. Glacier Peak, Mt. Rainier, Mt. Adams, Mt. Hood, and Mt. Mazama all have inception ages of 400-600 ka. Mt. St. Helens, Mt. Jefferson, Newberry Volcano, Mt. Shasta and Lassen Domefield have more recent inception ages of 200-300 ka. Only the Sisters cluster and Mt. Baker have established eruptive histories spanning less than 50 kyr. Ancestral volcanoes centered 5-20 km from active stratocones appear to have similar total durations (200-600 kyr), but are less well exposed and dated. The underlying mechanisms governing volcano lifecycles are cryptic, presumably involving tectonic and plumbing changes and perhaps circulation cycles in the mantle wedge, but are remarkably consistent along the arc.

  8. Mt. Fuji, Japan

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] Click on image to view the movie

    The nearly perfectly conical profile of Fuji soars 3,776 meters (12,388 feet) above sea level on southern Honshu, near Tokyo. The highest mountain in Japan, Fuji is the country's most familiar symbol. The summit of this graceful, dormant volcano is broken by a crater 610 meters (2,000 feet) in diameter. The crater is ringed by eight jagged peaks. The five Fuji Lakes lie on the northern slopes of the mountain, all formed in the wake of lava flows. Mirrored in the still waters of Kawaguchi-ko, the most beautiful of the five lakes, is a reflection of Fuji. Part of Fuji-Hakone-Izu National Park, Fuji last erupted for a two-month period starting in November 1707, covering Tokyo, some 100 kilometers (60 miles) away, with a layer of ash. According to legend, Fuji arose from the plain during a single night in 286 BC. Geologically, the mountain is much older than this.

    Considered sacred by many, Fuji is surrounded by temples and shrines. Thousands of pilgrims climb the mountain each year as part of their religious practice, hoping to reach the summit by dawn to watch the sunrise. This animated fly-by was created by draping visible and near infrared image data over a digital topography model, created from ASTER's stereo bands. The spatial resolution of both the image and topography is 15 m. The image is centered at 35.3 degrees north latitude, 138.7 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  9. Mt. Fuji, Japan

    NASA Image and Video Library

    2001-10-22

    The nearly perfectly conical profile of Fuji soars 3,776 meters (12,388 feet) above sea level on southern Honshu, near Tokyo. The highest mountain in Japan, Fuji is the country's most familiar symbol. The summit of this graceful, dormant volcano is broken by a crater 610 meters (2,000 feet) in diameter. The crater is ringed by eight jagged peaks. The five Fuji Lakes lie on the northern slopes of the mountain, all formed in the wake of lava flows. Mirrored in the still waters of Kawaguchi-ko, the most beautiful of the five lakes, is a reflection of Fuji. Part of Fuji-Hakone-Izu National Park, Fuji last erupted for a two-month period starting in November 1707, covering Tokyo, some 100 kilometers (60 miles) away, with a layer of ash. According to legend, Fuji arose from the plain during a single night in 286 BC. Geologically, the mountain is much older than this. Considered sacred by many, Fuji is surrounded by temples and shrines. Thousands of pilgrims climb the mountain each year as part of their religious practice, hoping to reach the summit by dawn to watch the sunrise. This animated fly-by was created by draping visible and near infrared image data over a digital topography model, created from ASTER's stereo bands. The spatial resolution of both the image and topography is 15 m. The image is centered at 35.3 degrees north latitude, 138.7 degrees east longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11166

  10. Mt. Fuji, Japan

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] Click on image to view the movie

    The nearly perfectly conical profile of Fuji soars 3,776 meters (12,388 feet) above sea level on southern Honshu, near Tokyo. The highest mountain in Japan, Fuji is the country's most familiar symbol. The summit of this graceful, dormant volcano is broken by a crater 610 meters (2,000 feet) in diameter. The crater is ringed by eight jagged peaks. The five Fuji Lakes lie on the northern slopes of the mountain, all formed in the wake of lava flows. Mirrored in the still waters of Kawaguchi-ko, the most beautiful of the five lakes, is a reflection of Fuji. Part of Fuji-Hakone-Izu National Park, Fuji last erupted for a two-month period starting in November 1707, covering Tokyo, some 100 kilometers (60 miles) away, with a layer of ash. According to legend, Fuji arose from the plain during a single night in 286 BC. Geologically, the mountain is much older than this.

    Considered sacred by many, Fuji is surrounded by temples and shrines. Thousands of pilgrims climb the mountain each year as part of their religious practice, hoping to reach the summit by dawn to watch the sunrise. This animated fly-by was created by draping visible and near infrared image data over a digital topography model, created from ASTER's stereo bands. The spatial resolution of both the image and topography is 15 m. The image is centered at 35.3 degrees north latitude, 138.7 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. Earthquakes & Volcanoes, Volume 23, Number 6, 1992

    USGS Publications Warehouse

    ,; Gordon, David W.

    1993-01-01

    Earthquakes and Volcanoes is published bimonthly by the U.S. Geological Survey to provide current information on earthquakes and seismology, volcanoes, and related natural hazards of interest to both generalized and specialized readers.

  12. 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.

  13. 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 ...

  14. Iceland: Eyjafjallajökull Volcano

    Atmospheric Science Data Center

    2013-04-17

    article title:  Eyjafjallajökull Volcano Ash Plume Particle Properties     ... satellite flew over Iceland's erupting Eyjafjallajökull volcano on April 19, 2010, its Multi-angle Imaging SpectroRadiometer (MISR) ...

  15. 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.

  16. 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

  17. [Hg 5O 2(OH) 4][(UO 2) 2(AsO 4) 2]: A complex mercury(II) uranyl arsenate

    NASA Astrophysics Data System (ADS)

    Yu, Yaqin; Jiang, Kai; Albrecht-Schmitt, Thomas E.

    2009-07-01

    Under mild hydrothermal conditions UO 2(NO 3) 2·6H 2O, Hg 2(NO 3) 2·2H 2O, and Na 2HAsO 4·7H 2O react to form [Hg 5O 2(OH) 4][(UO 2) 2(AsO 4) 2] (HgUAs-1). Single crystal X-ray diffraction experiments reveal that HgUAs-1 possesses a pseudo-layered structure consisting of two types of layers: ∞2[HgO(OH)4] and ∞2[(UO)2(AsO)2]. The ∞2[HgO(OH)4] layers are complex, and contain three crystallographically unique Hg centers. The coordination environments and bond-valence sum calculations indicate that the Hg centers are divalent. The ∞2[(UO)2(AsO)2] layers belong to the Johannite topological family. The ∞2[HgO(OH)4] and ∞2[(UO)2(AsO)2] layers are linked to each other through μ2-O bridges that include Hg⋯O=U=O interactions.

  18. Coordination of Advanced Solar Observatory (ASO) Science Working Group (SWG) for the study of instrument accommodation and operational requirements on space station

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1989-01-01

    The objectives are to coordinate the activities of the Science Working Group (SWG) of the Advanced Solar Observatory (ASO) for the study of instruments accommodation and operation requirements on board space station. In order to facilitate the progress of the objective, two conferences were organized, together with two small group discussions.

  19. Electronic properties of highly-active Ag3AsO4 photocatalyst and its band gap modulation: an insight from hybrid-density functional calculations.

    PubMed

    Reunchan, Pakpoom; Boonchun, Adisak; Umezawa, Naoto

    2016-08-17

    The electronic structures of highly active Ag-based oxide photocatalysts Ag3AsO4 and Ag3PO4 are studied by hybrid-density functional calculations. It is revealed that Ag3AsO4 and Ag3PO4 are indirect band gap semiconductors. The Hartree-Fock mixing parameters are fitted for experimental band gaps of Ag3AsO4 (1.88 eV) and Ag3PO4 (2.43 eV). The smaller electron effective mass and the lower valence band edge of Ag3AsO4 are likely to be responsible for the superior photocatalytic oxidation reaction to Ag3PO4. The comparable lattice constant and analogous crystal structure between the two materials allow the opportunities of fine-tuning the band gap of Ag3AsxP1-xO4 using a solid-solution approach. The development of Ag3AsxP1-xO4 should be promising for the discovery of novel visible-light sensitized photocatalysts.

  20. Volcanoes and global catastrophes

    NASA Technical Reports Server (NTRS)

    Simkin, Tom

    1988-01-01

    The search for a single explanation for global mass extinctions has let to polarization and the controversies that are often fueled by widespread media attention. The historic record shows a roughly linear log-log relation between the frequency of explosive volcanic eruptions and the volume of their products. Eruptions such as Mt. St. Helens 1980 produce on the order of 1 cu km of tephra, destroying life over areas in the 10 to 100 sq km range, and take place, on the average, once or twice a decade. Eruptions producing 10 cu km take place several times a century and, like Krakatau 1883, destroy life over 100 to 1000 sq km areas while producing clear global atmospheric effects. Eruptions producting 10,000 cu km are known from the Quaternary record, and extrapolation from the historic record suggests that they occur perhaps once in 20,000 years, but none has occurred in historic time and little is known of their biologic effects. Even larger eruptions must also exist in the geologic record, but documentation of their volume becomes increasingly difficult as their age increases. The conclusion is inescapable that prehistoric eruptions have produced catastrophes on a global scale: only the magnitude of the associated mortality is in question. Differentiation of large magma chambers is on a time scale of thousands to millions of years, and explosive volcanoes are clearly concentrated in narrow belts near converging plate margins. Volcanism cannot be dismissed as a producer of global catastrophes. Its role in major extinctions is likely to be at least contributory and may well be large. More attention should be paid to global effects of the many huge eruptions in the geologic record that dwarf those known in historic time.

  1. Global Volcano Model

    NASA Astrophysics Data System (ADS)

    Sparks, R. S. J.; Loughlin, S. C.; Cottrell, E.; Valentine, G.; Newhall, C.; Jolly, G.; Papale, P.; Takarada, S.; Crosweller, S.; Nayembil, M.; Arora, B.; Lowndes, J.; Connor, C.; Eichelberger, J.; Nadim, F.; Smolka, A.; Michel, G.; Muir-Wood, R.; Horwell, C.

    2012-04-01

    Over 600 million people live close enough to active volcanoes to be affected when they erupt. Volcanic eruptions cause loss of life, significant economic losses and severe disruption to people's lives, as highlighted by the recent eruption of Mount Merapi in Indonesia. The eruption of Eyjafjallajökull, Iceland in 2010 illustrated the potential of even small eruptions to have major impact on the modern world through disruption of complex critical infrastructure and business. The effects in the developing world on economic growth and development can be severe. There is evidence that large eruptions can cause a change in the earth's climate for several years afterwards. Aside from meteor impact and possibly an extreme solar event, very large magnitude explosive volcanic eruptions may be the only natural hazard that could cause a global catastrophe. GVM is a growing international collaboration that aims to create a sustainable, accessible information platform on volcanic hazard and risk. We are designing and developing an integrated database system of volcanic hazards, vulnerability and exposure with internationally agreed metadata standards. GVM will establish methodologies for analysis of the data (eg vulnerability indices) to inform risk assessment, develop complementary hazards models and create relevant hazards and risk assessment tools. GVM will develop the capability to anticipate future volcanism and its consequences. NERC is funding the start-up of this initiative for three years from November 2011. GVM builds directly on the VOGRIPA project started as part of the GRIP (Global Risk Identification Programme) in 2004 under the auspices of the World Bank and UN. Major international initiatives and partners such as the Smithsonian Institution - Global Volcanism Program, State University of New York at Buffalo - VHub, Earth Observatory of Singapore - WOVOdat and many others underpin GVM.

  2. Transatrial access for left atrial pressure (LAP) monitoring line placement in arterial switch operation (ASO) in neonates.

    PubMed

    Akhtar, Mohammad Irfan; Hamid, Mohammad; Amanullah, Muneer; Ahsan, Khalid

    2013-11-01

    Left Atrial pressure monitoring is a useful and accurate method to guide Left ventricle filling in the patients who undergo Arterial switch operation for transposition of great arteries. We have used a different technique in three TGA patients for LA pressure monitoring line placement. After cleaning and draping,right internal jugular vein (rt IJV) located through 22G venous cannula, guide wire was put in followed by sliding the 22G x 8cm vygon arterial catheter over the guide wire into the right atrium that was directed transatrially into LA by the operating surgeon during atrial septum repair. The catheter was secured by silk on the neck and dressed with transparent dressing and was kept for a period of 48-72 hrs. LA pressure monitoring is helpful in anticipating LV dysfunction in ASO.

  3. Li3Al(MoO2)2O2(AsO4)2

    PubMed Central

    Hajji, Mounir; Zid, Mohamed Faouzi; Driss, Ahmed

    2009-01-01

    Single crystals of trilithium(I) aluminium(III) bis­[dioxidomolybdenum(VI)] dioxide bis­[arsenate(V)], Li3AlMo2As2O14, have been prepared by solid-state reaction at 788 K. The structure consists of AsO4 tetra­hedra, AlO6 octa­hedra and Mo2O10 groups sharing corners to form a three-dimensional framework containing channels running respectively along the [100] and [010] directions, where the Li+ ions are located. This structure is compared with compounds having (MX 2O12)n chains (M = Mo, Al and X = P, As) and others containing M 2O10 (M = Mo, Fe) dimers. PMID:21582037

  4. K0.12Na0.54Ag0.34Nb4O9AsO4

    PubMed Central

    Chérif, Saïda Fatma; Zid, Mohamed Faouzi; Driss, Ahmed

    2011-01-01

    Potassium sodium silver tetra­niobium nona­oxide arsenate, K0.12Na0.54Ag0.34Nb4AsO13, synthesized by solid-state reaction at 1123 K, adopts a three-dimensional framework delimiting tunnels running along [001] in which occupationally disordered sodium, silver, and potassium ions are located. Of the 11 atoms in the asymmetric unit (two Nb, one As, one Ag, one K, one Na and fiveO), nine are located on special positions: one Nb and the K, Ag, Na and two O atoms are situated on mirror planes, the other Nb is on a twofold rotation axis, and the As atom and one O atom are on sites of m2m symmetry. PMID:21522808

  5. 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.”

  6. 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.

  7. High Rate GPS on Volcanoes

    NASA Astrophysics Data System (ADS)

    Mattia, M.

    2005-12-01

    The high rate GPS data processing can be considered as the "new deal" in geodetic monitoring of active volcanoes. Before an eruption, infact, transient episodes of ground displacements related to the dynamics of magmatic fluids can be revealed through a careful analysis of high rate GPS data. In the very first phases of an eruption the real time processing of high rate GPS data can be used by the authorities of Civil Protection to follow the opening of fractures field on the slopes of the volcanoes. During an eruption large explosions, opening of vents, migration of fractures fields, landslides and other dangerous phenomena can be followed and their potential of damage estimated by authorities. Examples from the recent eruption of Stromboli volcano and from the current activities of high rate GPS monitoring on Mt. Etna are reported, with the aim to show the great potential and the perspectives of this technique.

  8. 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.

  9. Deep structure and origin of active volcanoes in China

    NASA Astrophysics Data System (ADS)

    Zhao, D.

    2010-12-01

    Recent geophysical studies have provided important constraints on the deep structure and origin of the active intraplate volcanoes in Mainland China. Magmatism in the western Pacific arc and back-arc areas is caused by the corner flow in the mantle wedge and dehydration of the subducting slab (e.g., Zhao et al., 2009a), while the intraplate magmatism in China has different origins. The active volcanoes in Northeast China (such as the Changbai and Wudalianchi) are caused by hot upwelling in the big mantle wedge (BMW) above the stagnant slab in the mantle transition zone and deep slab dehydration as well (Zhao et al., 2009b). The Tengchong volcano in Southwest China is caused by a similar process in the BMW above the subducting Burma microplate (or Indian plate) (Lei et al., 2009a). The Hainan volcano in southernmost China is a hotspot fed by a lower-mantle plume which may be associated with the Pacific and Philippine Sea slabs' deep subduction in the east and Indian slab's deep subduction in the west down to the lower mantle (Lei et al., 2009b; Zhao, 2009). The stagnant slab finally collapses down to the bottom of the mantle, which can trigger the upwelling of hot mantle materials from the lower mantle to the shallow mantle beneath the subducting slabs and may cause the slab-plume interactions (Zhao, 2009). References Lei, J., D. Zhao, Y. Su, 2009a. Insight into the origin of the Tengchong intraplate volcano and seismotectonics in southwest China from local and teleseismic data. J. Geophys. Res. 114, B05302. Lei, J., D. Zhao, B. Steinberger et al., 2009b. New seismic constraints on the upper mantle structure of the Hainan plume. Phys. Earth Planet. Inter. 173, 33-50. Zhao, D., 2009. Multiscale seismic tomography and mantle dynamics. Gondwana Res. 15, 297-323. Zhao, D., Z. Wang, N. Umino, A. Hasegawa, 2009a. Mapping the mantle wedge and interplate thrust zone of the northeast Japan arc. Tectonophysics 467, 89-106. Zhao, D., Y. Tian, J. Lei, L. Liu, 2009b. Seismic

  10. ASoP (v1.0): a set of methods for analyzing scales of precipitation in general circulation models

    NASA Astrophysics Data System (ADS)

    Klingaman, Nicholas P.; Martin, Gill M.; Moise, Aurel

    2017-01-01

    General circulation models (GCMs) have been criticized for their failure to represent the observed scales of precipitation, particularly in the tropics where simulated daily rainfall is too light, too frequent and too persistent. Previous assessments have focused on temporally or spatially averaged precipitation, such as daily means or regional averages. These evaluations offer little actionable information for model developers, because the interactions between the resolved dynamics and parameterized physics that produce precipitation occur at the native gridscale and time step. We introduce a set of diagnostics (Analyzing Scales of Precipitation, version 1.0 - ASoP1) to compare the spatial and temporal scales of precipitation across GCMs and observations, which can be applied to data ranging from the gridscale and time step to regional and sub-monthly averages. ASoP1 measures the spectrum of precipitation intensity, temporal variability as a function of intensity and spatial and temporal coherence. When applied to time step, gridscale tropical precipitation from 10 GCMs, the diagnostics reveal that, far from the dreary persistent light rainfall implied by daily mean data, most models produce a broad range of time step intensities that span 1-100 mm day-1. Models show widely varying spatial and temporal scales of time step precipitation. Several GCMs show concerning quasi-random behavior that may influence and/or alter the spectrum of atmospheric waves. Averaging precipitation to a common spatial ( ≈ 600 km) or temporal (3 h) resolution substantially reduces variability among models, demonstrating that averaging hides a wealth of information about intrinsic model behavior. When compared against satellite-derived analyses at these scales, all models produce features that are too large and too persistent.

  11. Seismic activity of Erebus volcano, antarctica

    NASA Astrophysics Data System (ADS)

    Kaminuma, Katsutada

    1987-11-01

    Mount Erebus is presently the only Antarctic volcano with sustained eruptive activity in the past few years. It is located on Ross Island and a convecting anorthoclase phonolite lava lake has occupied the summit crater of Mount Erebus from January 1973 to September 1984. A program to monitor the seismic activity of Mount Erebus named IMESS was started in December 1980 as an international cooperative program among Japan, the United States and New Zealand. A new volcanic episode began on 13 September, 1984 and continued until December. Our main observations from the seismic activity from 1982 1985 are as follows: (1) The average numbers of earthquakes which occurred around Mount Erebus in 1982, 1983 and January August 1984 were 64, 134 and 146 events per day, respectively. Several earthquake swarms occurred each year. (2) The averag number of earthquakes in 1985 is 23 events per day, with only one earthquake swarm. (3) A remarkable decrease of the background seismicity is recognized before and after the September 1984 activity. (4) Only a few earthquakes were located in the area surrounding Erebus mountain after the September 1984 activity. A magma reservoir is estimated to be located in the southwest area beneath the Erebus summit, based on the hypocenter distributions of earthquakes.

  12. 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

  13. The mixed anion mineral parnauite Cu 9[(OH) 10|SO 4|(AsO 4) 2]·7H 2O—A Raman spectroscopic study

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Keeffe, Eloise C.

    2011-10-01

    The mixed anion mineral parnauite Cu 9[(OH) 10|SO 4|(AsO 4) 2]·7H 2O from two localities namely Cap Garonne Mine, Le Pradet, France and Majuba Hill mine, Pershing County, Nevada, USA has been studied by Raman spectroscopy. The Raman spectrum of the French sample is dominated by an intense band at 975 cm -1 assigned to the ν1 (SO 4) 2- symmetric stretching mode and Raman bands at 1077 and 1097 cm -1 may be attributed to the ν3 (SO 4) 2- antisymmetric stretching mode. Two Raman bands 1107 and 1126 cm -1 are assigned to carbonate CO 32- symmetric stretching bands and confirms the presence of carbonate in the structure of parnauite. The comparatively sharp band for the Pershing County mineral at 976 cm -1 is assigned to the ν1 (SO 4) 2- symmetric stretching mode and a broad spectral profile centered upon 1097 cm -1 is attributed to the ν3 (SO 4) 2- antisymmetric stretching mode. Two intense bands for the Pershing County mineral at 851 and 810 cm -1 are assigned to the ν1 (AsO 4) 3- symmetric stretching and ν3 (AsO 4) 3- antisymmetric stretching modes. Two Raman bands for the French mineral observed at 725 and 777 cm -1 are attributed to the ν3 (AsO 4) 3- antisymmetric stretching mode. For the French mineral, a low intensity Raman band is observed at 869 cm -1 and is assigned to the ν1 (AsO 4) 3- symmetric stretching vibration. Chemical composition of parnauite remains open and the question may be raised is parnauite a solid solution of two or more minerals such as a copper hydroxy-arsenate and a copper hydroxy sulphate.

  14. Of Rings and Volcanoes

    NASA Astrophysics Data System (ADS)

    2002-01-01

    show it. The bright spot close to the equator is the remnant of a giant storm in Saturn's extended atmosphere that has lasted more than 5 years. The present photo provides what is possibly the sharpest view of the ring system ever achieved from a ground-based observatory . Many structures are visible, the most obvious being the main ring sections, the inner C-region (here comparatively dark), the middle B-region (here relatively bright) and the outer A-region, and also the obvious dark "divisions", including the well-known, broad Cassini division between the A- and B-regions, as well as the Encke division close to the external edge of the A-region and the Colombo division in the C-region. Moreover, many narrow rings can be seen at this high image resolution , in particular within the C-region - they may be compared with those seen by the Voyager spacecraft during the flybys, cf. the weblinks below. This image demonstrates the capability of NAOS-CONICA to observe also extended objects with excellent spatial resolution. It is a composite of four short-exposure images taken through the near-infrared H (wavelength 1.6 µm) and K (2.2 µm) filters. This observation was particularly difficult because of the motion of Saturn during the exposure. To provide the best possible images, the Adaptive Optics system of NAOS was pointed towards the Saturnian moon Tethys , while the image of Saturn was kept at a fixed position on the CONICA detector by means of "differential tracking" (compensating for the different motions in the sky of Saturn and Tethys). This is also why the (faint) image of Tethys - visible south of Saturn (i.e., below the planet in PR Photo 04a/02 ) - appears slightly trailed. Io - volcanoes and sulphur ESO PR Photo 04b/02 ESO PR Photo 04b/02 [Preview - JPEG: 400 x 478 pix - 39k] [Normal - JPEG: 800 x 955 pix - 112k] ESO PR Photo 04c/02 ESO PR Photo 04c/02 [Preview - JPEG: 400 x 469 pix - 58k] [Normal - JPEG: 800 x 937 pix - 368k] Caption : PR Photo 04b/02 shows

  15. Japan: Tradition and Change.

    ERIC Educational Resources Information Center

    Ellington, Lucien

    This textbook is designed to increase students' awareness of Japan. The study of Japan is worthwhile because Japan currently is and likely will continue to be one of the world's most important countries. U.S. knowledge of Japan is still quite limited compared to the level of understanding most Japanese exhibit about the United States. It is hoped…

  16. 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

  17. 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