2004 Fiscal Year Final Research Report Summary
Bedrock structure related to active faults in Lijiang basin, Yunnan, China, and its seismic microzoning
| Project/Area Number |
14404020
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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 | 海外学術 |
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| Research Field |
Natural disaster science
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| Research Institution | Kyoto University |
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Principal Investigator |
AKAMATSU Junpei Kyoto University, Disaster Prevention Research Institute, Associate Professor, 防災研究所, 助教授 (10027279)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Kajuro Kyoto University, Disaster Prevention Research Institute, Research Associate, 防災研究所, 助手 (20135510)
KOMAZAWA Masao Geological Survey of Japan, AIST, Chief Researcher, 地質情報研究部門, 主任研究員 (40357025)
MORIKAWA Hitoshi Tokyo Institute of Technology, Interdisciplinary Graduate School of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (60273463)
YANO Takao Tottori University, Faculty of Regional Sciences, Professor, 地域学部, 教授 (30133151)
NISHIMURA Keiichi Okayama University of Science, Faculty of Informatic, Professor, 総合情報学部, 教授 (60025468)
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| Project Period (FY) |
2002 – 2004
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| Keywords | 3D bedrock structure / Lijaing-Jianchuan Fault / pull-apart basin / gravity survey / remote sensing / crustal movement from GPS |
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| Research Abstract |
The 1996 Lijiang Earthquake of M7.0 brought serious damage to the Lijiang basin. Although its seismogenic fault is considered to be the Xueshan fault lying along the western edge of the basin, the most severely damaged zone was located 1.5-2 km far from the basin edge, and there was a remarkable change in degree of damage near along the Lijiang-Jianchuan fault zone, which crosses the basin in the southern part. As an issue of microzoning, gravity survey and geologic study were conducted to reveal the bedrock structure associated active faults. 3D gravity basement was modeled for Lijiang basin, adjacent Lashi basin, and Heqing basin ranging south. The depth to bedrock reaches more than 2km for each basin. Satelite images were analyzed to map active faults which were checked in the field. GPS observation was carried out to monitor the crustal movement associated the faults. The basins structure and its genesis were discussed on the basis of pull-apart structure controlled by the regional tectonics in northern Yunnan. The anomalous distribution of damage should be attributed to the fault-related bedrock configuration with steep relief (basin-edge effect and/or focusing effect), and to the geological condition of fault zone in the sediments.
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