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| Coseismic vertical deformation of the MS8.0 Wenchuan earthquake from repeated levelings and its constraint on listric fault geometry |
| Qingliang Wang1, Duxin Cui1, Xi Zhang1, Wenping Wang1, Jinwen Liu1, Kang Tian1, Zhaoshan Song2 |
1 Second Monitoring Center, China Earthquake Administration, Xi’an 710054, China
2 First Monitoring Center, China Earthquake Administration, Tianjin 300180, China |
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Abstract The devastating MS8.0 Wenchuan earthquake ruptured two large parallel thrust faults along the middle segment of the Longmenshan thrust belt. Preseismic and postseismic leveling data indicated the hanging wall of the Yingxiu- Beichuan-Nanba thrust fault mainly presented coseismic uplift with respect to the reference point at Pingwu county town, and the observed maximum uplift of 4.7 m is located at Beichuan county (Qushan town) which is about 100 m west of the fault scarp. The foot wall of the Yingxiu-Beichuan-Nanba thrust fault mainly showed subsidence with maximum subsidence of 0.6 m near the rupture. By employing a listric dislocation model, we found that the fault geometry model of exponential dip angle δ= 88°×[1-exp(-9/h)] with depth of 18 km and uniform thrust-slip of 5.6 m could fit the observed coseismic vertical deformation very well, which verifies the listric thrust model of the Longmenshan orogenic zone.
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Received: 23 September 2009
Published: 10 December 2009
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| Fund:National Key Basic Research 973 project (2004CB418403) and National Natural Science Foundation of China (40974062) |
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Corresponding Authors:
Qingliang Wang
E-mail: wangql_cea@sina.com
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| [1] |
Yu Wang, Shengli Ma, Toshihiko Shimamoto, Lu Yao, Jianye Chen, Xiaosong Yang, Honglin He, Jiaxiang Dang, Linfeng Hou, Tetsuhiro Togo. Internal structures and high-velocity frictional properties of Longmenshan fault zone at Shenxigou activated during the 2008 Wenchuan earthquake[J]. Earthquake Science, 2014, 27(5): 499-528. |
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