The Holocene Activity Evidence of the Yema River-Daxue Mountain Fault in Western Qilian Mountain

作     者：LUO Hao HE Wengui YUAN Daoyang SHAOYanxiu 

作者机构：Key Laboratory of Engineering GeomechanicsInstitute of Geology and Geophysics Chinese Academy of Sciences Earthquake Research Institute of LanzhouChina Earthquake Administration Lanzhou National Geophysical Observatory 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2013年第87卷第6期

页      面：1569-1584页

核心收录：

学科分类：070905[理学-第四纪地质学] 0709[理学-地质学] 07[理学] 

基　　金：granted by the National Natural Science Foundation of China (Grant No. 40872132, 41030317) Chinese Academy of Sciences Key Project XDB03020201 

主　　题：paleoearthquake earthquake recurrence interval reference magnitude Yema River-Daxue Mountain fault Altyn Tagh fault 

摘      要：Altyn Tagh fault controls the deformation characteristics of the northern margin of the Qinghai-Tibet *** sinistral slip rate of the eastern segment of the fault reduces gradually where the reduction transforms into the deformation within Qilian Mountain,forming a series of thrust faults and strike-slip *** them,the Yema River-Daxue Mountain fault is one of the important structural transform faults in the study *** on the differences of the geometrical characteristics and activities,the fault is divided into four segments,the Yema River segment,the Shibandun segment,the Liushapo segment and the Baishitougou segment,among which the former three are Holocene active faults,and the Baishitougou segment belongs to late Pleistocene *** excavated trenches imply a total of 6 paleoearthquake events,and at least 4 events have occurred during Holocene,whose occurrence times are 8300±700 yr BP,6605±140 yr BP,4540±350 yr BP,2098±47 yr BP,*** recurrence interval is 2600±600 yr BP that is close to the lapsed time of the last one,2098±47 yr BP,which suggests that the Yema River-Daxue Mountain fault is in a high risk of major earthquakes in the *** vertical coseismic displacements of the four Holocene paleoearthquake events are 100 cm,42 cm,40 cm and 50 cm,respectively,the horizontal coseismic displacements are 5 m,4.5-5.5 m,5-8 m and 4-5.5 m,separately,and then the reference magnitude of the paleoearthquake events is conjectured to be M7.6±0.1.