| Project/Area Number |
18K13640
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 17040:Solid earth sciences-related
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| Research Institution | The University of Tokyo (2020-2021)
Japan Agency for Marine-Earth Science and Technology (2018-2019) |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
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| Keywords | 沈み込み帯 / スラブ内地震 / 温度 / 水 / データ科学 / 流体 / 熱伝導率 / 蛇紋岩 / 温度構造 / 水の移動 / ベイズ推定 |
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| Outline of Final Research Achievements |
I constructed a framework to predict the thermal structure of subduction zones including its uncertainty based on Bayesian inversion. The obtained depth uncertainties for isotherms are about 10 and 20 km for the 600 and 1200C isotherms, respectively. When this uncertainty is considered, the location of the serpentinite-out boundary matches that of the lower plane of double seismic zone in Tohoku region. It suggests that dehydration may be important in triggering intermediate-depth seismicity. I also conducted numerical modeling to investigate possible impact of anisotropic thermal conductivity in the mantle wedge on the subduction zone thermal structure. I found that the obtained temperature differences between the anisotropic and isotropic cases are only up to 30C within the slab. The effects of rock deformation on fluid migration is also tested in a simple model setting.
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| Academic Significance and Societal Importance of the Research Achievements |
スラブ内地震の発生には、スラブから放出される水が重要な役割を果たすと考えられている。そしてスラブからの水の放出率と発生場所は温度に大きく支配される。本研究では沈み込み帯の温度構造を、データ科学的手法を用いて物性や観測データの不確かさまで含めて評価する枠組みを構築することに成功した。また岩石変形が水の移動に及ぼす影響に関しても新たな知見を得た。その結果、スラブ内地震発生の仕組みをより定量的に議論することが可能になった。
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