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| Analysis of the Wenchuan Ms8.0 Earthquake’s Co-seismic Stress and Displacement Change by Using the Finite Element Method | |
| 作者姓名： | SUN Dongsheng WANG Lianjie WANG Hongcai MA Yinsheng ZHOU Chunjing and CUI Junwen |
| 作者单位： | 1 Key Laboratory of Neotectonic Movement and Geohazard, Ministry of Land and Resources, Beijing 100081, China. 2 Institute of Geomechanics, Chinese academy of Geological Sciences, Beijing 100081, China. 3 Institute of Geology, Chinese academy of Geological Sciences, Beijing 100037, China |
| 基金项目： | This research was supported by the Sinoprobe Deep Exploration in China (SinoProbe-07), research funds of the Institute of Geomechanics, Chinese Academy of Geological Sciences (GrantNo.DZLXJK201105), and National Basic Research Program of China (973 Program) (GrantNo.2008CB425702). |
| 摘 要： | The variation of in situ stress before and after earthquakes is an issue studied by geologists. In this paper, on the basis of the fault slip dislocation model of Wenchuan Ms8.0 earthquake, the changes of co-seismic displacement and the distribution functions of stress tensor around the Longmen Shan fault zone are calculated. The results show that the co-seismic maximum surface displacement is 4.9 m in the horizontal direction and 6.5 m in the vertical direction, which is almost consistent with the on-site survey and GPS observations. The co-seismic maximum horizontal stress in the hanging wall and footwall decreased sharply as the distance from the Longmen Shan fault zone increased. However, the vertical stress and minimum horizontal stress increased in the footwall and in some areas of the hanging wall. The study of the co-seismic displacement and stress was mainly focused on the long and narrow region along the Longmen Shan fault zone, which coincides with the distribution of the earthquake aftershocks. Therefore, the co-seismic stress only affects the aftershocks, and does not affect distant faults and seismic activities. The results are almost consistent with in situ stress measurements at the two sites before and after Wenchuan Ms8.0 earthquake. Along the fault plane, the co-seismic shear stress in the dip direction is larger than that in the strike direction, which indicates that the faulting mechanism of the Longmen Shan fault zone is a dominant thrust with minor strike-slipping. The results can be used as a reference value for future studies of earthquake mechanisms. |
| 关 键 词： | Wenchuan Ms8.0 earthquake co-seismic stress field co-seismic displacement field finite element method in situ stress measurement |
| 收稿时间： | 2012/12/17 0:00:00 |
| 修稿时间： | 2013/5/16 0:00:00 |
Analysis of the Wenchuan Ms8.0 Earthquake's Co-seismic Stress and Displacement Change by Using the Finite Element Method |
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| Authors: | SUN Dongsheng WANG Lianjie WANG Hongcai MA Yinsheng ZHOU Chunjing CUI Junwen |
| Institution: | 1. Key Laboratory of Neotectonic Movement and Geohazard, Ministry of Land and Resources, Beijing 100081, China; Institute of Geomechanics, Chinese academy of Geological Sciences, Beijing 100081, China 2. Institute of Geomechanics, Chinese academy of Geological Sciences, Beijing 100081, China 3. Institute of Geology, Chinese academy of Geological Sciences, Beijing 10003 7, China |
| Abstract: | The variation of in situ stress before and after earthquakes is an issue studied by geologists. In this paper, on the basis of the fault slip dislocation model of Wenchuan Ms8.0 earthquake, the changes of co‐seismic displacement and the distribution functions of stress tensor around the Longmen Shan fault zone are calculated. The results show that the co‐seismic maximum surface displacement is 4.9 m in the horizontal direction and 6.5 m in the vertical direction, which is almost consistent with the on‐site survey and GPS observations. The co‐seismic maximum horizontal stress in the hanging wall and footwall decreased sharply as the distance from the Longmen Shan fault zone increased. However, the vertical stress and minimum horizontal stress increased in the footwall and in some areas of the hanging wall. The study of the co‐seismic displacement and stress was mainly focused on the long and narrow region along the Longmen Shan fault zone, which coincides with the distribution of the earthquake aftershocks. Therefore, the co‐seismic stress only affects the aftershocks, and does not affect distant faults and seismic activities. The results are almost consistent with in situ stress measurements at the two sites before and after Wenchuan Ms8.0 earthquake. Along the fault plane, the co‐seismic shear stress in the dip direction is larger than that in the strike direction, which indicates that the faulting mechanism of the Longmen Shan fault zone is a dominant thrust with minor strike‐slipping. The results can be used as a reference value for future studies of earthquake mechanisms. |
| Keywords: | Wenchuan Ms8 0 earthquake co-seismic stress field co-seismic displacement field finite element method in situ stress measurement |
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