四川芦山2022年6月M_(S)6.1地震的发震构造及其与2013年4月M_(S)7.0地震关系的探讨  

DISCUSSION ON SEISMOGENIC STRUCTURE OF THE JUNE 2022 M_(S)6.1 EARTHQUAKE AND ITS RELATIONSHIP WITH THE APRIL 2013 M_(S)7.0 EARTHQUAKE IN LUSHAN,SICHUAN PROVINCE

作　　者：陈翰林 王勤彩[2] 张金川[3] 刘瑞丰[1] CHEN Han-lin;WANG Qin-cai;ZHANG Jin-chuan;LIU Rui-feng(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Jiangsu Earthquake Agency,Nanjing 210014,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国地震局地震预测研究所,北京100036 [3]江苏省地震局,南京210014

出　　处：《地震地质》2023年第5期1233-1246,共14页Seismology and Geology

基　　金：中国地震局地震预测研究所基本科研业务专项(2021IEF0603,CEAIEF2022030100);陕西省自然科学基础研究计划项目(2021JM-600)共同资助

摘　　要：文中对2013年4月—2022年7月发生在芦山震区的地震进行重定位,并反演了芦山2022年6月1日M_(S)6.1地震的震源机制解。芦山M_(S)6.1地震序列的震源深度北浅南深,断层长约10km,自深向浅破裂。通过分析芦山震区的发震构造和地震活动特征,认为震源断层为一条走向NE、倾向SE的盲逆冲断层,其与2013年M_(S)7.0地震走向NE、倾向NW的主逆冲断层及其上盘走向NE、倾向SE的反向逆冲断层共同组成双层“Y”字形结构。进一步综合分析库仑应力变化,认为2013年芦山M_(S)7.0地震对2022年芦山M_(S)6.1地震具有抑制作用。In this paper,we relocated earthquakes occurred from April 2013 to July 2022 in Lushan seismic zone,inversed focal mechanism solution of the Lushan M_(S)6.1 earthquake on June 1,2022 and discussed the seismogenic structure of the Lushan M_(S)6.1 earthquake and its relationship with the M_(S)7.0 earthquake in April 2013.The results of the focal mechanism solution show that the Lushan M_(S)6.1 earthquake in 2022 is a thrust earthquake.The strike,dip and azimuth of nodal planeⅠare 228°,46°and 104°and for nodal planeⅡare 28°,46°and 76°respectively.The results of earthquake relocation show that the focal depth of the Lushan M_(S)6.1 earthquake sequence is shallow in the north and deep in the south,the fault length is about 10km.The focal depth is mainly concentrated between 10km to 19km.The fault dip is southeast with an angle of 60°.The initial rupture point of the main shock of the Lushan M_(S)6.1 earthquake is at a depth of 20km,located at the deepest part of the fault.The fault ruptured from deep to shallow.The Lushan M_(S)7.0 earthquake occurred on April 2013 strikes northeast and dips northwestward,but there exists a reverse fault in the aftershock sequence that has the same direction of strike but the opposite direction of dip.This reverse fault is consistent with the strike and dip of the M_(S)6.1 earthquake occurred in June 2022.It appears as two parallel faults in the profile.In addition to the reverse fault on the west side,the embryonic of another reverse fault seems to appear on the east side of the middle of earthquake sequence.These faults are about 10km away from the surface.The distribution of earthquakes in two northwest-oriented depth profiles shows that the dip angles of the main shock and the reverse fault of the M_(S)7.0 earthquake is different at different locations,and these faults are not simple straight planar sections.From one year after occurrence of the M_(S)7.0 earthquake to occurrence of the M_(S)6.1 earthquake,the seismic activity on the main fault decreased but the seismic a

关 键 词：芦山地震 地震精定位 震源机制 发震构造 

分 类 号：P315.2[天文地球—地震学]