2022 Fiscal Year Final Research Report
Unified Understanding of Slow and Regular Earthquakes from Nonequilibrium Physics Point of View
| Project Area | Science of slow earthquakes |
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| Project/Area Number |
16H06478
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| Research Category |
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Osaka University (2018-2020, 2022)
The University of Tokyo (2016-2017) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
住野 豊 東京理科大学, 理学部第一部応用物理学科, 准教授 (00518384)
鈴木 岳人 青山学院大学, 理工学部, 助教 (10451874)
山口 哲生 九州大学, 工学研究院, 准教授 (20466783)
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| Project Period (FY) |
2016-06-30 – 2021-03-31
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| Keywords | スロー地震 / 非線形動力学 / アナログ実験 |
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| Outline of Final Research Achievements |
Using analog experiments and mathematical models that can systematically control heterogeneous geological structures, we clarify the mechanism of slow earthquake generation from the physical point of view of "diversity of slip phenomena due to geological heterogeneity". In particular, we show how the spacetime evolution patterns of slip in various heterogeneous structures are related to geological/geophysical observations. We reproduce the acceleration phenomenon of slow slip to fast slip and elucidate the quantitative conditions that separate slow and fast slip.
Analog sample deformation experiments successfully reproduced the flow and fracture patterns observed in outcrops, supporting the geological scenario for slow earthquakes from a mechanical point of view. Numerical simulation on fault roughness structure reproduces the essential features of slow slips such as source migration and precursory slip against large earthquakes.
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| Free Research Field |
非平衡物理学
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| Academic Significance and Societal Importance of the Research Achievements |
数理モデル化を通じてより一般的な理解も深まった。例えば、一様な系で自発的に出現する遅い滑りのモデル化と観測との比較により、スロー地震には地質学的不均質性が不可欠であることを示すこともできた。また、断層の滑りが生態系の個体数変動と共通の枠組で理解できることも示した。複雑ネットワーク分野の概念を用いた新しい時系列解析手法により、通常の地震もスロー地震もマグニチュード時系列に相関があることが分かった。これらの理解を応用して、木材接合部や靴底など不均質材料の設計にもスロー地震研究の知見が生かせることが分かった。
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