| 2008年汶川大地震同震、震后形变和应力及对松坪沟地质灾害的影响 |
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| 关键词:Longmen Shan Wenchuan earthquake Xinmo landslide post-seismic deformation Coulomb stress |
| 基金项目:国家自然科学基金项目“龙门山前缘新生代沉积不均匀性的动力学机制模拟研究”(编号: 41874114);中国地质科学院基本科研业务费项目“青藏高原东缘地表过程与深部动力作用研究”(编号: YYWF201720) |
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| The Co-seismic and Post-seismic Deformation and Stress of Wenchuan Earthquake in 2008 and Their Influence on the Songpinggou Geohazards |
| In 2017, the Xinmo landslide in Songpinggou, Maoxian County, Sichuan Province, caused serious casualties. In addition to analyzing factors such as rainfall and engineering geology, previous researchers have proposed that the earthquakes also played an important role in the formation of Xinmo landslides. However, there is still a lack of detailed quantitative analysis. In this study, based on the crustal structure and GPS observations in the Longmen Shan area and combined with the co-seismic rupture model of Wenchuan earthquake obtained by USGS, the authors calculated the co-seismic and post-seismic deformation and stress caused by the Wenchuan earthquake by using a viscoelastic layered semi-infinite space model (PSGRN/PSCMP program). The deformation and stress in Songpinggou were analyzed in detail. The results show that the co-seismic rupture of Wenchuan earthquake caused significant surface displacement in Songpinggou area, and the post-seismic deformation continued to strengthen in this area due to the viscoelastic relaxation effect. The eastward and northward displacements caused by the co-seismic rupture of Wenchuan earthquake in Songpinggou area were 26.8~42.3 cm and 7.4~8.0 cm respectively. This area is in the transition zone of vertical displacement rising or descending, with a change of –0.1~1.7 cm. 9 years after the earthquake, on the basis of the co-seismic results, the eastward displacement continued to increase by about 2.5 cm, and the northward displacement increased by 7.4~8.0 cm. The northwestern section of Songpinggou was in the vertical displacement upward zone, while the southeastern section was in the vertical displacement downward zone. The post-seismic deformation caused the average topographic gradient to increase, which has been conducive to the the occurrence of landslide disaster. In view of the uncertain pattern of Songpinggou fault slipping, the coulomb stress changes caused by the Wenchuan earthquake will have different effects on its seismicity. |
| XIE Shi-liang,SUN Yu-jun.2021.The Co-seismic and Post-seismic Deformation and Stress of Wenchuan Earthquake in 2008 and Their Influence on the Songpinggou Geohazards[J].Acta Geoscientica Sinica,42(5):691-700. |
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