A5028159551- earthquake and tectonic studies
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- Hydrocarbon exploration and reservoir analysis
- Methane Hydrates and Related Phenomena
- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Groundwater and Isotope Geochemistry
- Geological and Geophysical Studies
- Earthquake Detection and Analysis
- Geophysical Methods and Applications
- Radioactive contamination and transfer
- Geology and Paleoclimatology Research
- Geotechnical Engineering and Underground Structures
- Seismic Imaging and Inversion Techniques
- Nuclear Physics and Applications
- CO2 Sequestration and Geologic Interactions
- Landslides and related hazards
- Geothermal Energy Systems and Applications
- High-pressure geophysics and materials
- Hydrology and Watershed Management Studies
- Clay minerals and soil interactions
- Rock Mechanics and Modeling
- X-ray Spectroscopy and Fluorescence Analysis
- Earthquake and Disaster Impact Studies
Tohoku University
2024
Itochu (Japan)
2024
SCREEN (Japan)
2015
ON Semiconductor (United States)
2015
Geological Survey of Japan
2014
Kitasato University
2010
Mitsubishi Materials (Japan)
1998-2006
Iwate University
1999
Satou Hospital
1993
National Research Institute for Earth Science and Disaster Resilience
1975-1989
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...
Continuous monitoring of the crustal tilt is one most effective approaches for purpose earthquake prediction. Drilling a borehole not so expensive as construction an underground vault, which necessary installation water-tube tiltmeters and horizontal pendulum tiltmeters, station possible to be made even in plain area. The National Research Center Disaster Prevention has only developed boreholetype tiltmeter itself but improved drilling techniques methods tiltmeter. force-balanced down-hole...
遠隔離島小規模地熱の探査に関する研究協力（ESSEIプロジェク卜）の一環として，インドネシア，フローレス島中部のパジャワ地熱地域とその周辺地域において，1998年以来，広域地質の研究が実施されてきた．この地域では4Ma以降，中央部と南海岸部において火山活動が起こった．この両地域はフローレス島からアロール島にかけて特徴的なエシェロン状火山島構造の要素を構成している．これら両地域では，過去250万年の聞に，約800mの隆起が起こった．中央部においては約2.5Maにウェラスカルデラが形成され，その後カルデラ火山活動の後は，ほとんど，火山活動が終息している．南海岸部では，4Ma 以降，現在に至るまで，火山活動が続いている．とくに顕著な出来事はパジャワリフトゾーンの出現であり，これは東側の北進するオーストラリア付加体ブロックと西側の相対的に静止したスンダランドブロックとの聞に生じた南北方向の左横ずれせん断応力に関係づけられる．パジャワリフトゾーンはおそらく0.8-0.2...
Continued to previous works at Iwatsuki and Shimohsa, S wave velocities in deep soil deposits were measured by using the observation well Fuchu Deep-Borehole Crustal Activity Observatory of National Research Center for Disaster Prevention, Japan.Measurements conducted 17 different depths borehole bottom with depth 2, 750m intervals 100-250m. waves excited SH generator on ground surface. The observed a set three component seismometers assembled into specially designed capsule. capsule can fix...
abstract Deep S-wave velocity measurements were planned at two separate sites in the Tokyo area from earthquake engineering point of view, and actually carried out down to 2 3 km depth using geophysical observation wells. S-waves produced by means ordinary small explosions a specially designed SH-wave generator. A set three component seismometers was installed capsule having device that is clamped borehole wall. Measurements bottom wells conducted about 15 different depths intervals 100 500...
Shear wave attenuation in deep soil deposits down to 2.3km depth was directly and systematically measured at one of the deep-borehole observatories which were constructed for geophysical observations Tokyo metropolitan area. Introducing newly designed SH-wave generator an S-wave source, down-hole measurements 12 different depths conducted intervals 0.1-0.3km. Attenuation factors determined by spectral ratio method linearly inverted QS-values under assumption frequency-independent QS.The...
Although low-sulfidation epithermal deposits, including the Hosokura deposit (Ag–Pb–Zn) in Miyagi Prefecture, northern Japan, are globally significant metal sources, their ore deposition mechanisms not thoroughly understood . This study aimed to construct a genetic model for this by focusing on richest vein, Fuji, and test using numerical simulation of formation transitions fossil geothermal system. It was proposed that mixing neutral hydrothermal fluids (~260 °C) ascending through vein with...
A deep shear wave velocity measurement was carried out down to 3500m in Tokyo area by a temporary use of the Iwatsuki earthquake observation well constructed National Research Center for Disaster Prevention Japan.Shear waves were produced mainly means ordinary small explosions and supplementarily specially designed SH generator. set three component seismometers installed capsule having clamping device borehole wall. Sequent measurements conducted 16 different depths bottom at intervals...
Even though epithermal vein-type deposits are the main sources of Au and Ag worldwide, accurate three-dimensional modeling vein structures extraction high-grade zones still difficult because geologic structure heterogeneities scarcity available data, mostly obtained via drilling. Accordingly, by selecting a low-sulfidation Au–Ag deposit in Philippine archipelago, we develop an efficient reliable workflow for determining spatial distribution Au-rich veins detail transport hydrothermal fluids....
地下水の水質や物理化学パラメータなどの地球化学特性は, その起源および岩石・鉱物との相互作用などの影響によって形成される. 本研究では、約9300点の深層地下水データのうち, 非火山地域のデータの抽出および地質による分類を地理情報システム (GIS) 上で行い, 約5200点のデータを4つのタイプの地質 (堆積岩類, 付加コンプレックス, 火山岩類, 深成岩類) を基に分類した後, 各地質における深層地下水の水温, pH, 主要イオン (Na, K, Mg, Ca, Cl, SO4, HCO3) 濃度の特徴の比較を行った. その結果, 総陽イオン濃度の平均値は各地質中の地下水間で有意に異なっており, 堆積岩類 (66.7 meq l-1), 火山岩類 (43.0 付加コンプレックス (24.6 深成岩類 (11.0 l-1) の順に低い傾向を示した. pHの平均値は地質間で大きな差は見られなかったが, 水温の平均値は火山岩類中の地下水が最も高い値を示した. 主要陽イオン Mg) 濃度の平均値は4種類すべてにおいて堆積岩類中の地下水が最も高かった. また, 主要陰イオンは...
At the Iwo-jima, ground-tilt observation, precise geodetic survey and sea level observation have been carried out relationship between volcanic activities crustal deformation studied. The maximum value of upheaval which was geodetically measured about 1.9 meters during 8 years from 1976 to 1984.
Continued to the previous work at Iwatsuki similar experiment on shear wave velocity measurement in deep soil deposits was carried out earthquake observation well Shimofusa, Chiba Prefecture, which constructed by National Research Center for Disaster Prevention of Japan.Shear waves were produced means SH generator ground surface. In 15 different depths intervals 100-250m, sequent down borehole bottom with depth 2.3km conducted using a set three component geophones installed specially...
The recent population increase and economic development have increased the energy demand in many countries. As global fossil fuel reserves are limited, it is highly likely that supply of fuels will come under pressure alternative energies throughout world become essential. Assuming a Japanese 64 million 2100 with 20% power per capita from present level, we studied electric situation by conducting trial calculation maximum potential hydroelectric energy, renewable produced Japan. findings...
In-situ stress measurements were made in a 450m deep well tuff by the hydrofracturing technique. Six hydrofractures created at depths between 263 and 436m. The results show that maximum horizontal compressive stress, σHmax, increases with depth from 180 to 210 bars minimum σHmin, 110 130 over same range. stresses of 400m determined be 205 bars, respectively. A borehole televiewer was used detect new fractures hydrofracturing. Two six runs clear indicate direction N25°±10°E. This agrees those...