Deep electrical structures of Qinzhou-Fangcheng Junction Zone in Guangxi and seismogenic environment of the 1936 Lingshan M6^(3/4)earthquake  

作　　者：Bin ZHOU Chunheng YAN Yan ZHAN Xiangyu SUN Sha LI Xiang WEN Yajun MO Yongdong YUAN Yuan YUAN Meili HUANG 

机构地区：[1]Earthquake Agency of Guangxi Zhuang Autonomous Region,Nanning,530022,China [2]State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing,100029,China [3]Guangxi Geophysical Survey Institute,Liuzhou,545005,China

出　　处：《Science China Earth Sciences》2024年第2期584-603,共20页中国科学（地球科学英文版）

基　　金：supported by the Science for Earthquake Resilience Program of the China Earthquake Administration(Grant Nos.XH24033B,XH22004YA);the Guangxi Scientific Research and Technology Development Plan Project(Grant Nos.1377002,14124004-4-8);the Earthquake Prediction Open Fund Project of China Earthquake Administration(Grant No.2021EF0F02)。

摘　　要：The tectonic position of the southwest section of the Qinzhou Bay-Hangzhou Bay Tectonic Junction Zone(QHTJZ)can be determined by examining the Qinzhou-Fangcheng Junction Zone(QFJZ)in Guangxi.This zone is significant because it was the location of the largest earthquake ever recorded in the inland region of South China,specifically the 1936 Lingshan M6^(3/4)earthquake in Guangxi.Therefore,this region serves as an optimal location for researching the origins of intraplate earthquakes in South China.This study presents a display of a broadband magnetotelluric(MT)prospecting profile that traverses the Guangxi QFJZ and the Lingshan earthquake zone,extending from the northwest(NW)to the southeast(SE).A resistivity structure model was generated using three-dimensional(3D)inversion technology along the profile.The main faults in QFJZ were analyzed in terms of their deep extension forms and tectonic attributes.This analysis was performed by integrating the results obtained from geology,gravity,wave velocity ratio,Global Position System(GPS),and geothermal flow.The results showed that(1)the Dongzhong-Xiaodong fault(DXf),the eastern Fangcheng-Lingshan fault(FLf2),and the eastern Hepu-Beiliu fault(HBf2)were all trans-crustal deep faults,and crust-mantle ductile shear zones developed in the deep part.Two electrical boundary zones,DXf and HBf2,were identified.DXf inclined towards the northwest,while HBf2 inclined towards the southeast.The FangchengLingshan fault(FLf)exhibits a tectonic style resembling a“flower”shape in the upper crust.In the deeper section,it is characterized by an electrical boundary zone that gradually slopes towards the southeast direction.(2)The Hunan-Guangxi Passive Continental Margin(HGPCM)on the NW side of DXf had a stratified resistivity structure and relatively stable Bouguer gravity anomalies,which conformed to the quasi-craton tectonic attribute of the local failure at the southeastern margin of the Yangtze Block(YB).The southeastern side of this block is marked by the presence of the QFJZ and

关 键 词：South China Block Qinzhou-Fangcheng Junction Zone Magnetotelluric 1936 Lingshan M6^(3/4)earthquake Deep seismogenic environment 

分 类 号：P315[天文地球—地震学]