2022 Fiscal Year Final Research Report
Estimation of strong ground motion characteristics of outer-rise earthquake along the Japan-Kuril trench
| Project/Area Number |
19K15075
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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 22020:Structure engineering and earthquake engineering-related
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | アウターライズ / 千島海溝 / 日本海溝 / 震源特性 / 短周期地震動 |
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| Outline of Final Research Achievements |
In order to improve the accuracy of prediction of strong ground motions for outer-rise earthquakes that occur within the oceanic plate before subduction outside the trench, we investigated the source characteristics of the outer-rise earthquake that occur around the Japan and Kuril trench. We applied the S-wave coda spectral ratio method and the spectral inversion method to evaluate the source characteristics of the plate boundary earthquake, intraslab earthquake, and outer rise earthquake that occurred around the target region. We confirmed a strong trend of short-period excitations of intra-slab and outer-rise earthquakes, compared with plate boundary earthquakes. Although the number of strong motion records of outer-rise earthquakes is limited, there was a tendency for the stress drop to increase with the focal depth.
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| Free Research Field |
地震工学
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| Academic Significance and Societal Importance of the Research Achievements |
2011年東北地方太平洋沖地震以降，東北地方太平洋側の三陸沖では大規模なアウターライズ地震の発生が指摘されている．海溝外側の沈み込む前の海洋プレート内で発生するアウターライズ地震では，陸域の観測点から離れており，またその他の地震タイプと比較して，観測記録の蓄積が十分でないため，その研究例はまだまだ少ないのが現状であるが，その広帯域強震動特性の評価は重要である．
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