Influences of across-strike heterogeneous viscosity on the earthquake cycle in a three-dimensional strike-slip fault model

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

作者机构：Mengcheng National Geophysical ObservatorySchool of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei230026China Jiangsu Earthquake AgencyNanjing210014China CAS Center for Excellence in Comparative PlanetologyHefei230026China 

出 版 物：《Earthquake Research Advances》 (地震研究进展（英文）)

年 卷 期：2023年第3卷第3期

页      面：30-41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：supported by the National Natural Science Foundation of China (42074105 92155204) the Joint Open Fund of Mengcheng National Geophysical Observatory (No. MENGO-202004) 

主　　题：Across-strike viscosity variation Friction law Power-law rheology Earthquake cycle Asymmetric interseismic deformation 

摘      要：Geodetic observations have shown that there exist large differences in the viscosity of the deep lithosphere across many large strike-slip *** in lithospheric viscosity structure can influence the efficiency of stress transfer and thus may have a significant effect on the earthquake *** now,how the lateral viscosity variation across strike-slip faults affects the earthquake cycles is still not well ***,we investigate the effects of across-strike viscosity variation on long-term earthquake behaviors with a three-dimensional strike-slip fault *** model is a quasi-static model which is controlled by the slip-weakening friction law and powerlaw *** comparing with the reference case,we find that low viscosity on one side of the fault results in a smaller rupture area but with a higher Coulomb stress drop on the ruptured fault *** addition,low viscosity also leads to a small Coulomb stress accumulation *** combined effects increase the earthquake recurrence interval by approximately 10%and the earthquake moments by about 30%when the low viscosity is related to a geothermal gradient of 30 K/*** addition,across-strike viscosity variation causes asymmetric interseismic ground surface deformation *** the viscosity contrast increases,the difference in the interseismic ground surface deformation rate between the two sides of the fault gradually increases,although the asymmetric feature is not *** asymmetry of interseismic ground deformation rate across a strike-slip fault is supposed to result in asymmetric coseismic deformation if the long-term plate motion velocity is *** a result,this kind of asymmetry of interseismic deformation may influence the evaluation of potential earthquake hazards along large strike-slip faults with lateral viscosity contrast.