Co and postseismic fault slip models of the 2022 M_(W)6.7 Menyuan earthquake reveal conjugated faulting tectonics at the central section of the Lenglongling fault  

作　　者：Zilong He Wenbin Xu Zhiwei Li Lei Xie Guangcai Feng Nan Fang Xiaoge Liu Kai Sun Zhidan Chen Zhihui Zhu 

机构地区：[1]School of Geosciences and Info-Physics,Central South University,Changsha 410083,China [2]Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Central South University,Changsha 410083,China [3]School of Civil Engineering,Central South University,Changsha 410083,China

出　　处：《Earthquake Science》2024年第4期277-303,共27页地震学报（英文版）

基　　金：the National Science Fund for Distinguished Young Scholars(No.41925016);National Key Research and Development Program(No.2022YFB3903602);National Natural Science Foundation of China(No.42174023);the Frontier Cross Research Project of Central South University(No.2023QYJC006).

摘　　要：The 2022 M_(W)6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap,providing an opportunity to study the regional seismogenic characteristics and seismic hazards.Here we use interferometric synthetic aperture radar(InSAR)and seismic data to study the mainshock rupture,early afterslip and the second largest aftershock of the 2022 Menyuan earthquake sequences.Our modeling results show that the mainshock ruptured the Lenglongling fault and the Tuolaishan fault with a maximum slip of~3 m.Rapid postseismic transient deformation occurred at the center of the Lenglongling fault.Our afterslip modeling reveals that the majority of afterslip occurred in the deeper part of the Lenglongling fault.A high-angle conjugated faulting event is found at the middle section of the Lenglongling fault.We use the stress inversion to investigate the possible triggering mechanism of the conjugated rupture event.The results indicate the maximum principal stress direction is in~222°,forming a~22°angle between the conjugated fault of second largest aftershock and the mainshock.The calculated normal stress changes indicate the region is within a pull-apart stress field,which favors such a conjugated rupturing event.Our study will help understand the rupture behavior of such kind of conjugated fault in other regions.

关 键 词：coseismic displacement and slip postseismic deformation and afterslip conjugate rupture coulomb stress change stress inversion 

分 类 号：P542.3[天文地球—构造地质学] P315.2[天文地球—地质学]