A5057958874- earthquake and tectonic studies
- Geological and Geochemical Analysis
- Groundwater and Isotope Geochemistry
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Seismology and Earthquake Studies
- Hydrocarbon exploration and reservoir analysis
- High-pressure geophysics and materials
- Geochemistry and Geologic Mapping
- Isotope Analysis in Ecology
- Earthquake Detection and Analysis
- Geological Modeling and Analysis
- Radioactive contamination and transfer
- CO2 Sequestration and Geologic Interactions
- Karst Systems and Hydrogeology
- Geological and Geophysical Studies
- Cryospheric studies and observations
- Nuclear Physics and Applications
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Groundwater flow and contamination studies
- Seismic Waves and Analysis
- Earthquake and Disaster Impact Studies
- Remote Sensing and Land Use
Geological Survey of Japan
2015-2024
National Institute of Advanced Industrial Science and Technology
2013-2024
Japan Research Institute
2017
Toyo University
2014
University of Arizona
2004
Tokyo Institute of Technology
1985
Research Article| December 01, 1995 Volatile transport in a convecting magma column: Implications for porphyry Mo mineralization Hiroshi Shinohara; Shinohara 1Geological Survey of Japan, 1-1-3 Higashi, Tsukuba, 305, Japan Search other works by this author on: GSW Google Scholar Kohei Kazahaya; Kazahaya Jacob B. Lowenstern 2U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Geology (1995) 23 (12): 1091–1094....
Large changes in the surface manifestation of degassing activity were observed from 1990 to 1999 at summit crater Iwodake cone Satsuma-Iwojima volcano. During this period, a new high-temperature fumarolic area formed center floor and became vent with diameter 40 m. Altered volcanic rocks ejected during course formation. Although glass fragments ash, comes altered rhyolite that covers floor. The highest temperature equilibrium temperatures gases had maximum about 900°C beginning flux SO2,...
Abstract Non-volcanic hot springs are generally believed to originate through circulation of meteoric or buried sea water heated at depth. In this study, we report the geochemical characteristics Arima and Takarazuka spring waters, known as Arima-type deep brine, in a forearc region southwestern Japan. We examine 14 samples determine levels 12 solute elements components isotopic ratios H, He, C, O, Sr, perform correlation analysis data deduce source materials origin brine. Moreover,...
Research Article| May 01, 2004 Gigantic SO2 emission from Miyakejima volcano, Japan, caused by caldera collapse Kohei Kazahaya; Kazahaya 1Geological Survey of Institute Advanced Science and Technology, Tsukuba, Ibaraki 305-8567, Japan Search for other works this author on: GSW Google Scholar Hiroshi Shinohara; Shinohara Kozo Uto; Uto Masanobu Odai; Odai 2Japan Meteorological Agency, Chiyoda-ku, Tokyo 100-8122, Yasuhiro Nakahori; Nakahori Hirokazu Mori; Mori Hideki Iino; Iino Makoto...
The chemical and isotopic (D, 18O, 34S) compositions were determined for 19 fumarolic gases, 11 hot spring waters 3 meteoric collected from Satsuma-Iwojima volcanic island, Japan. gases discharge over a wide range of temperature (from 877 to 99°C), but are likely be derived common parent gas with deduced composition (μmol/mol): H2O:975000, CO2:3800, total S:9800 (with an average oxidation state 3.4), HCl:5800, HF:300, H2:5000, CO:15, He:0.05, Ar:0.25, N2:60. variation in different fumaroles...
We report the quantitative evaluation of UV scattering effect on SO 2 emission rate measurement by compact spectrometer system. Plume spectra were obtained simultaneously at three measuring points with different distance to volcanic plume. The apparent absorbance decreases increasing plume and attenuation becomes stronger shorter wavelength bands. In addition, intensity depends column concentration. underestimation measured caused leads rate. was not significant any band (<±10%) 0.6 km...
We report new chemical and nitrogen isotopic data from 29 volcanic hydrothermal gas samples covering eight centers in the Izu‐Bonin‐Mariana (IBM) arc to investigate sources, flux, mass balance of at a “cool” convergent margin. The majority have high N 2 /He (1217–17,300) low CO /N 2,exc. (78–937), implying addition subducting slab. This inference is supported by positive (i.e., sediment‐like) δ 15 values (up 5.5‰) most samples. exception these trends Agrigan Mariana arc, with (∼200),...
Satsuma-Iwojima volcano continuously releases magmatic volatiles from the summit of Iwodake, a rhyolitic lava dome. The temperature fumaroles is high, between 800° and 900°C, water-rich composition volcanic gases has not changed essentially over past 10 years. Sulfur dioxide flux measured by COSPEC almost constant with an average 550 t/d since 1975. present gas likely degassed magma whose similar to that erupted in 1934, 2 km east Satsuma-Iwojima. Comparison silicate melt inclusions...
All available SO 2 flux data for 32 years (1975–2006) of Japanese volcanoes, accounting about 10% the world's arc were compiled to evaluate temporal variation each volcano and estimate time‐averaged flux. The revealed that 6 volcanoes (Tokachi, Asama, Aso, Sakurajima, Satsuma‐Iwojima, Suwanosejima volcanoes) out 17 significantly degassing usually contributed more than 94% total annual was 2.2 Tg a −1 , which includes intense Miyakejima after 2000, raised figure from 1.4 indicating single...
近年のHi-netによる地震観測網により,我が国の沈み込み帯における地殻・マントル中の熱水流体の不均質分布による三次元地震波速度構造の異常や深部流体に関連する深部低周波地震の存在などが明らかになってきた。地球物理学的な観測結果に基づく岩石学的水循環モデルは,固体地球内部の水収支を定量化し,滞留時間の長い深層地下水中には検出可能な濃度でスラブ脱水起源の深部流体が流入していることを示す。また,内陸地震発生における深部流体の役割も,近年重要視されている。モデルは主に地球物理学的観測やシミュレーション等の結果に基づいたものであるため,地球化学的・地質学的な物質科学的証拠の蓄積はモデルの高度化にとって重要である。そこで,我々は西南日本の中国–四国–近畿地方において深層地下水の同位体化学的特徴の検討を行い,地下水系に混入する深部流体の広域分布について明らかにした。その結果,マグマ水と似た同位体組成をもつ深部流体,すなわち,スラブ起源深部流体のLi/Cl比(重量比)が0.001より高いことを示した。Li/Cl比は,天水起源の淡水で希釈されても大きく変化しないことが期待されるため,深部流体の指標...
Soil gas surveys were carried out in November 1999 and October 2000 at Satsuma-Iwojma volcano, southwest Japan. The chemical composition of the soil was a mixture CO2 air components, with concentrations ranging from 0.03 to 59 vol%. origin evaluated on basis variation δ13CCO2 concentration. Although most is biogenic origin, large volcanic contributions greater than 50% found close caldera rim, where temperature anomalies observed. Emission rate estimated by assuming simple mixing among...
To understand degassing processes during the 2000 Miyakejima volcanic activity, we applied following two methods : 1) repeated analyses of adhered water-soluble gas component such as SO4and Cl ions on ashes produced at eruptions from July 8 and mid-September, 2) SO2 flux measurements by COSPEC since August 26.The repetitive soluble show remarkable changrd in Cl/S. Until 18, SO4 concentrations are quite high always low with Cl/S 0.01-0.05, indicating that a certain mass groundwater existed...
The relationship between geological structure and helium isotopes is discussed for deep groundwaters from the Osaka sedimentary basin, southwest Japan, to understand dissolved He in groundwater hydrological application. Although this area shows no Quaternary volcanic activity, nearly upper mantle-like 3He/4He ratio (1.1 × 10-5) has been observed along fault system where basement rocks are outcropped. In contrast, lowest part of aquifers beneath Basin showed a wide variation (0.27-8 10-6),...
Research Article| February 01, 2016 Gas pathways and remotely triggered earthquakes beneath Mount Fuji, Japan Koki Aizawa; Aizawa * 1Earthquake Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan2Institute Seismology Volcanology, Faculty Sciences, Kyushu University, 2-5643-29 Shin'yama, Shimabara, Nagasaki 855-0843, *E-mails: aizawa@sevo.kyushu-u.ac.jp; uyeshima@eri.u-tokyo.ac.jp; y.yamaya@aist.go.jp; hase@gerd.co.jp; h.a.takahashi@aist.go.jp;...
Heliborne measurements of CO 2 /SO ratio in a volcanic plume were performed at Miyakejima volcano, which has degassed intensively since September, 2000. The repeated started October, 2000 and showed constant molar 0.75 ± 0.25 despite decreased SO emission rate from 42 kt/d late to 16 2001. also 21 8 content the magma is estimated be 1200 ppm based on mole S melt inclusions (1300 ppm). corresponds saturation pressure 280 MPa suggesting presence ‐rich bubbles chamber located 4 km. over year...
Abstract In the southwest Japan forearc, slab‐fluids produced from subducted materials migrate to crustal levels and appear as deep‐seated brine. We have analyzed for first‐time stable strontium isotopes in non‐volcanic spring water with high salinity, referred Arima‐type saline that likely originate slab‐fluid upwelled along major faults. The isotope compositions of are isotopically light (δ 88/86 Sr = 0.122–0.157‰) different those local bedrock near‐surface water. strontium‐enriched...