Estimation of 3D seismic velocity structure beneath Kii Peninsula in order to improve predictions of Nankai Trough megaquakes
| Project/Area Number |
23540496
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2011-04-28 – 2015-03-31
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| Project Status |
Completed (Fiscal Year 2014)
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| Budget Amount *help |
¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2013: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2012: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2011: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | 南海トラフ巨大地震 / 紀伊半島 / 地震波速度構造 / フィリピン海プレート / スラブ起源流体 / レシーバ関数 / トモグラフィ |
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| Outline of Final Research Achievements |
We tried to estimate 3D seismic velocity structure accurately beneath Kii Peninsula which is a part of the source area of Nankai Trough megaquakes and through which strong seismic waves propagate to the big cities in Kansai.
Results of the seismic tomography show that the generating areas of deep low frequency earthquakes at the depths of 30 - 40 km of the subducting Philippine Sea slab have low velocity anomalies. Other strong low velocity anomalies are widely distributed in the lower crust beneath northern Wakayama Prefecture where seismic activity is very high in the upper crust. These phenomena indicate that hydrous minerals in the slab dehydrate at the depths, and the discharged fluids move up to the mantle wedge or the lower crust, cause the low velocity anomalies and get involved in the occurrence of the earthquakes.
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Report
(5 results)
Research Products
(15 results)
