Paleoearthquake Investigation along the Chenghai Fault Zone since~500 ka,Southeast Margin of the Tibetan Plateau  

作　　者：YANG Shuaibin QIAO Yansong WU Zhonghai ZHANG Xujiao QI Lin HE Zexin LIANG Ying 

机构地区：[1]Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China [2]The Key Laboratory of Active Tectonics and Crustal Stability Assessment,Beijing 100081,China [3]School of Geosciences and Resources,China University of Geosciences,Beijing 100083,China

出　　处：《Acta Geologica Sinica(English Edition)》2021年第4期1332-1345,共14页地质学报（英文版）

基　　金：supported by Geological Survey Program(Grant No.12120114001501,DD20160306 and DD20160268);the National Natural Science Foundation of China(Grant No.41772383 and 41571013)。

摘　　要：The Chenghai fault zone is located in the Sichuan–Yunnan rhombus block,which is surrounded by the Honghe River,Xianshuihe–Xiaojiang,and Jinsha River fault zones.As a mid-continental active fault,it is one of the most important seismogenic fractures in the southeast margin of the Tibetan Plateau.Geological seismic study is an important supplement to the historical seismic record;therefore,identification of paleoearthquake events in this region is of great significance to reveal the pattern and mechanism of earthquake development.In this study,detailed investigation has been carried out on the earthquake traces that formed in the Quaternary sediments in the Jinsha River section of the Chenghai fault zone,and samples for dating chronology testing were also collected.Many paleoearthquake traces were discovered in the field,including earthquake fissions,dammed lake sediments and landslides,earthquake-generated rock falls,seismic faults,and sand liquefaction veins.The collected samples were tested using optically stimulated luminescence,electron-spin resonance,and U-series methods.A total of 68 chronological samples were dated,combined with the results of field investigations,and 10 large paleoearthquake events were discovered in this region since 500 ka,which are at approximately 450,400,345,300,250,190,155,105,75,and 25 ka.Ten tectonic activity periods that produced multiple paleoearthquake events were identified since 500 ka.This study identifies paleoearthquake events in longer scales,larger spaces,and more extensive sediments,which provides new perspectives and new ideas for paleoearthquake research.

关 键 词：PALEOEARTHQUAKE earthquake fission dammed lake earthquake-generated rock fall Chenghai fault zone 

分 类 号：P642.2[天文地球—工程地质学]