| Project/Area Number |
15340142
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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 |
Solid earth and planetary physics
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| Research Institution | Tohoku University |
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Principal Investigator |
FUJIMOTO Hiromi Tohoku University, Graduate School of Science, Professor, 大学院理学研究科, 教授 (50107455)
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| Co-Investigator(Kenkyū-buntansha) |
HINO Ryota Tohoku University, Graduate School of Science, Associate nrofessor, 大学院理学研究科, 助教授 (00241521)
MIURA Satoshi Tohoku University, Graduate School of Science, Associate professor, 大学院理学研究科, 助教授 (70181849)
NISHINO Minoru Tohoku University, Graduate School of Science, Research associate, 大学院理学研究科, 助手 (40322995)
SHINOHARA Masanao University of Tokyo, Earthquake Research Institute, Associate professor, 地震研究所, 助教授 (90242172)
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| Project Period (FY) |
2003 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥16,700,000 (Direct Cost: ¥16,700,000)
Fiscal Year 2006: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2003: ¥11,200,000 (Direct Cost: ¥11,200,000)
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| Keywords | subduction plate boundary / plate motion / seismic coupling / seafloor geodetic observation / precise seafloor positioning / ocean bottom pressure monitoring / Japan trench / off Fukushima Prefecture / 宮城県沖 / 非地震性すべり / 海底精密測位観察 / 海陸プレート境界 / 精密測位観測 / 海底傾斜観測 |
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| Research Abstract |
The objectives of this research program are to investigate for spatial and temporal variations in crustal deformation induced by the subducting plate motion through seafloor geodetic observation in the vicinity of the subduction plate boundary, and to estimate the repeatability of the seafloor geodetic observation.
Repeated precise seafloor positioning based on sea surface KGPS positioning and underwater acoustic ranging has been carried out off Iwate and Miyagi prefectures, and has been initiated off Fukushima Prefecture. Judging from seismic activities off Fukushima, seismic coupling on the plate boundary in the region can be relatively weak. However, land-based GPS observation in these several years suggests strong coupling off Fukushima as well as off Miyagi. Although the estimated error is fairly large in the crustal deformation obtained from two-year observations, the result shows that the seismic coupling off Fukushima is as strong as that off Miyagi. The coupling off Fukushima may possibly show temporal variation.
GPS/Acoustic (GPS/A) seafloor positioning off Kii Peninsula detected a large co-seismic crustal movement up to 30 cm associated with the 2004 earthquake (M7.4) off Kii Peninsula. The repeatability of the positioning obtained from an observation for two days is estimated to be about 3-5 cm. This value was larger than the estimated displacements at our GPS/A sites associated with the 2005 earthquake off Miyagi Prefecture. We confirmed that the value can be improved with higher GPS sampling.
Long-term ocean bottom pressure monitoring was carried out off Iwate Prefecture under two crossover points of the satellite tracks for altimetry. The results coincide with recent five ocean tide models within 1.3 cm in terms of root sum square of vector differences for eight principal constituents. Although we have acquired know-how for long-term ocean bottom pressure monitoring, we need more research works to get long-term stability of pressure monitoring.
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