The 2018 M_S 5.9 Mojiang Earthquake:Source model and intensity based on near-field seismic recordings

作     者：Xu Zhang Zhen Fu LiSheng Xu ChunLai Li Hong Fu 

作者机构：Institute of GeophysicsChina Earthquake Administration Earthquake Administration of Yunnan Province 

出 版 物：《Earth and Planetary Physics》 (地球与行星物理（英文版）)

年 卷 期：2019年第3卷第3期

页      面：268-281页

核心收录：

学科分类：07[理学] 0708[理学-地球物理学] 

基　　金：supported by the National Natural Science Foundation of China(project 41804088) the Special Fund of the Institute of Geophysics,China Earthquake Administration(project DQJB19B08) 

主　　题：2018 MS 5.9 Mojiang Earthquake near-field seismic recording finite-fault model intensity prediction focal mechanism solution 

摘      要：On September 8, 2018, an M_S 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings(epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the mainshock and some of the aftershocks and to invert for the finite-fault model of the *** focal mechanism solution of the mainshock and the relocation results of the aftershocks constrain the mainshock on a nearly vertical fault plane striking northeast and dipping to the southeast. The inversion of the finite-fault model reveals only a single slip asperity on the fault plane. The major slip is distributed above the initiation point, ～14 km wide along the down-dip direction and ～14 km long along the strike direction, with a maximal slip of ～22 cm at a depth of ～6 km. The focal mechanism solutions of the aftershocks show that most of the aftershocks are of the strike-slip type, a number of them are of the normal-slip type, and only a few of them are of the thrust-slip *** average, strike-slip is dominant on the fault plane of the mainshock, as the focal mechanism solution of the mainshock suggests, but when examined in detail, slight thrust-slip appears on the southwest of the fault plane while an obvious part of normal-slip appears on the northeast, which is consistent with what the focal mechanism solutions of the aftershocks display. The multiple types of aftershock focal mechanism solutions and the slip details of the mainshock both suggest a complex tectonic setting, stress setting, or both. The intensity contours predicted exhibit a longer axis trending from northeast to southwest and a maximal intensity of Ⅷ around the epicenter and in the northwest.