2001 Fiscal Year Final Research Report Summary
Research of tectonics in Asia and Pacific based on synthetic analysis of GPS data
| Project/Area Number |
11440129
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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 | The University of Tokyo |
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Principal Investigator |
KATO Teruyuki Earthquake Research Institute, Professor, 地震研究所, 教授 (80134633)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Shin'ichi Earthquake Research Institute, Research Associate, 地震研究所, 助手 (00334285)
KOTAKE Yoshiko Earthquake Research Institute, Research Associate, 地震研究所, 助手 (60012944)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Tectonics / GPS / Collision boundary / Indian plate / Sunda block / Amurian plate |
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| Research Abstract |
The purpose of the project was to synthesize published GPS velocity field in Asia and Pacific to delineate obtain a detailed tectonic velocity field of the area. To this end, we used more than seven articles to fit the velocities at the commonly occupied IGS sites in a least-square sense in ITRF97 reference frame. The obtained velocity field was referenced to the stable Eurasia to get tectonically easy-to-read map. Thus obtained map shows that the wide area of Asian continent is mostly affected by the collision of Indian sub-continent. More over, an acute clockwise rotation is found around the Xianshuihe-Xiaojiang fault zone in the central China, which push the Indo-China peninsula to south. We modeled the deformation field by the block-fault model introduced by Hashimoto and Jackson (1993). The result clearly showed blockwise motion of the area together with fan-shape spreading of the China continent due to the collision of India.
In order to investigate the effect of acute rotation of China block to Indo-China peninsula, we conducted GPS campaign observation in Thailand. The estimated velocities in Thailand did not show any significant deformation in the central part of the peninsula. However, the deformation seemed to distribute in the wide area crossing the Red River fault that runs NW-SE along the Vietnam, Laos and China border. In the north of China, on the other hand, Amurian plate was hypothesized to interpret small eastward displacement in Mongolia and Russia, though more detailed investigation is clearly needed.
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