| Project/Area Number |
10440129
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | Kochi University |
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Principal Investigator |
TABEI Takao Kochi Univ., Fac.Science, Associate Professor, 理学部, 助教授 (40207220)
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| Co-Investigator(Kenkyū-buntansha) |
KIMATA Fumiaki Nagoya Univ., Schl.Science, Associate Professor, 大学院・理学研究科, 助教授 (10089849)
HASHIMOTO Manabu Kyoto Univ., Dsiast.Prev.Res.Inst., Associate Professor, 防災研究所, 助教授 (20293962)
HIRAHARA Kazuro Nagoya Univ., Schl.Science, Professor, 大学院・理学研究科, 教授 (40165197)
KATO Teruyuki Univ.Tokyo, Earthq.Res.Inst., Professor, 地震研究所, 教授 (80134633)
MATSUSHIMA Takeshi Kyushu Univ., Fac.Science, Associate Professor, 大学院・理学研究科, 助教授 (40222301)
宮崎 真一 国土地理院, 地理地殻活動研究センター, 研究員
田中 寅夫 京都大学, 防災研究所, 教授 (40027222)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥9,400,000 (Direct Cost: ¥9,400,000)
Fiscal Year 2000: ¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1998: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Median Tectonic Line / GPS measurement / Crustal deformation / Fault lock and slip / Fault deep structure / 固着・すべり分布 / 地殻変動モデリング |
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| Research Abstract |
Main purpose of this study is to clarify deep structure and slip distribution of the Median Tectonic Line (MTL) in southwest Japan from dense GPS traverse measurements at the surface. We constructed 22 stations along a 220km-long line and conducted three campaign measurements in 1998-2000. We determined horizontal crustal velocities at 64 sites in total including adjacent continuous stations of the nationwide network. Campaign velocities obtained are so accurate as to show very good accordance to the velocities from continuous measurements.
We quantitatively discriminated deformation field into two categories : elastic deformation caused by the subduction of the Philippine Sea plate and block-like movements across the MTL.We made both forward and inversion modelings. In the former we extracted block motion across the MTL, fault locking in the uppermost part and steady slip at depth by calculating elastic deformation from a plate subduction model and subtracting it from the observed velocity field In the latter we simultaneously estimated plate subduction, block motion across the MTL and slip deficit in the uppermost part of MTL.Two modelings gave the nearly same results :
1. Southern block of the MTL moves westward at a rate of about 5mm/yr relative to the northern one, consistent to the geological right-lateral slip rate of 5-10mm/yr.
2. The block boundary does not agree with the stuface trace of the MTL, clearly displaced 20-30km to the north.
3. The above results are interpreted that the fault plane of MTL dips into the north at an angle of 30-40 degrees, and the uppermost part of MTL is locked to the depth of 15-20km and steady right-lateral slip occurs below. These results have been presented at several meetings in Japan and USA.The manuscript for the publication in the international journal is being prepared.
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