We thank China Earthquake Networks Center for providing the cat-alog of earthquake events,Sichuan Earthquake Networks Center for providing the catalog of aftershocks,Sichuan Earthquake Agency for providing the seismic phase observations used for earthquake relocation,and National Seismograph Network Data Backup Center for China Seis-mograph Network(https://doi.org/10.11998/SeisDmc/SN)of the Institute of Geophysics,China Earthquake Administration for providing the seismograms used in this study.We appreciate Professor Lupei Zhu for providing the gCAP program package,Professor Yongge Wan at the Institute of Disaster Prevention for providing the program to search the center of focal mechanism,some of the figures were created by Generic Mapping Tools(www.soest.hawaii.edu/gmt,last-accessed date 2021-11-11 （https://doi.org/10.11998/SeisDmc/SN）

Wessel et al.,2013),Additionally,we express special thanks to senior engineer Li Dahu at Sichuan Earthquake Agency for providing useful discussion of this analysis,and the anonymous reviewers for their valu-able suggestions which had greatly improved the quality of this manu-script.This Project is sponsored by The Key Project of Director Fund of Earthquake Agency of Inner Mongolia Autonomous Region,China(2020TM04),the Key Youth Task of Earthquake Emergency of China Earthquake Administration,China(CEA_EDEM-202103)and Project of Director Fund of Earthquake Agency of Inner Mongolia Autonomous Region,China(2019JC27). （2020TM04）