2013 Fiscal Year Final Research Report
Study on slip property of the slow earthquake source region in the transition zone on the subducting plate interface
| Project/Area Number |
23244091
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
KATO Aitaro 東京大学, 地震研究所, 准教授 (20359201)
IWASAKI Takaya 東京大学, 地震研究所, 教授 (70151719)
SAKAI Shinichi 東京大学, 地震研究所, 准教授 (00251455)
TAKEDA Tetsuya 防災科学技術研究所, 観測・予測研究領域地震・火山防災研究ユニット, 主任研究員 (80455253)
ASANO Yoichi 防災科学技術研究所, 観測・予測研究領域地震・火山防災研究ユニット, 主任研究員 (00399362)
SHIOMI Katsuhiko 防災科学技術研究所, 観測・予測研究領域地震・火山防災研究ユニット, 主任研究員 (20500375)
MATSUZAWA Takanori 防災科学技術研究所, 観測・予測研究領域地震・火山防災研究ユニット, 主任研究員 (90500744)
NANJO Kazuyoshi 防災科学技術研究所, 観測・予測研究領域地震・火山防災研究ユニット, 契約研究員 (10549504)
MAEDA Takuto 東京大学, 地震研究所, 助教 (90435579)
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| Project Period (FY) |
2011-04-01 – 2014-03-31
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| Keywords | スロー地震 / 沈み込み帯 / 深部低周波微動 / スロースリップ |
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| Research Abstract |
The catalog of the non-volcanic tremor occurring on the interface of the subducting Philippine Sea plate is reevaluated and new pattern of tremor migration and spatiotemporal evolution have been clarified. The tremor activity pattern indicates depth dependency along the dip direction. This suggests that the frictional property on the plate interface changes with depth. In order to reveal the depth dependency of tremor activity pattern, we deployed 80 seismometers for two years in western Shikoku which is one of most active tremor source areas in southwest Japan, changes along the dip direction of the plate interface. Our analysis of local and teleseismic seismograms revealed that the oceanic crust just beneath the tremor zone is characterized by low-V and high Vp/Vs. The flat geometry of the subducting plate interface corresponding to the inactive part of tremor zone may suggest that the geometrical irregularities of the plate control the slow earthquake activity.
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