2019 Fiscal Year Final Research Report
Development of a next-generation seismic source inversion method using volumetrically distributed moment tensor
| Project/Area Number |
16K05539
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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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| Co-Investigator(Kenkyū-buntansha) |
八木 勇治 筑波大学, 生命環境系, 教授 (50370713)
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Keywords | インバージョン解析 / 震源過程 / モーメントテンソル / 断層面形状 |
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| Outline of Final Research Achievements |
A flat fault plane is usually assumed in estimating slip distribution of an earthquake. However, actual seismic faults often have more complicated geometry, as suggested by recent observation with high resolution. In this study, we simultaneously estimated fault dip angles and slip distribution of the 2016 Kumamoto earthquake, which happened on two different fault planes. We also developed a new inversion method, in which moment tensors that can express slip of arbitrary directions (not confined to the directions parallel to the fault plane) were used to express slip on an assumed fault plane, and showed the validity of the method through synthetic tests and application to real seismic data.
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| Free Research Field |
固体地球物理学
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| Academic Significance and Societal Importance of the Research Achievements |
東北地方太平洋沖地震や熊本地震など，大地震が発生した際にはその滑り分布を的確に推定することが重要であり，求められた地震の滑り分布は，TVなどの報道でもしばしば目にする．しかし，標準的な解析手法は一枚の平面断層というかなり強い制限をかけており，得られた結果の信頼度もまた限定的である．本研究では，モデルの自由度を広げることによってより適切な解を選択することを行った．より良い滑り分布は，地震の物理の基礎的な理解の進展に寄与するだけでなく、余震や将来の大地震発生予測などにも生かされる重要な情報となる．
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