Influences of the heterogeneity of viscoelastic medium on postseismic deformation of the 2008 M_(W) 7.9 Wenchuan earthquake

作     者：Feng Li Peng Zhai Jinshui Huang Hongbo Tan Feng Li;Peng Zhai;Jinshui Huang;Hongbo Tan

作者机构：Mengcheng National Geophysical ObservatorySchool of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China Earthquake Administration of Jiangsu ProvinceNanjing210014China CAS Center for Excellence in Comparative PlanetologyHefei230026China 

出 版 物：《Geodesy and Geodynamics》 (大地测量与地球动力学（英文版）)

年 卷 期：2022年第13卷第1期

页      面：1-10页

核心收录：

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：This work is supported by the National Natural Science Foun-dation of China(42074105,41674096) Natural Science Foundation of Jiangsu Province(BK20131033)。 

主　　题：M_(W)7.9 Wenchuan earthquake Postseismic deformation Viscoelastic relaxation Horizontal heterogeneity Three-dimensional finite element 

摘      要：The study of postseismic deformation is important for constraining the viscoelastic properties of the Earth and inverting the post-earthquake process.The levelling survey revealed that the area near Bei-chuan elevated 5.3 cm about two years after the M_(W) 7.9 Wenchuan earthquake(05/12/2008),during which the area underwent significant downward movement.The GPS horizontal displacements showed a non-monotonic variation after the Wenchuan earthquake.In this study,a 3-D viscoelastic finite element model is employed to simulate the coseismic and postseismic deformation of the Wenchuan earthquake.The numerical simulations show that the lateral heterogeneity across the Longmenshan fault plays an important role in the postseismic displacements.The results reveal that the coseismic defor-mation is not sensitive to the horizontal heterogeneity,but the postseismic deformation is sensitive to it.The postseismic deformation of the horizontally heterogeneous model is generally consistent with the observations of all geodetic surveys,such as GPS,InSAR and levelling,but not for the horizontally homogenous model.We also find that the non-monotonous variation of the postseismic deformation of the Wenchuan earthquake could be explained by a viscoelastic relaxation model with lateral heterogeneous medium across the Longmenshan fault.