基于线性密集台阵的2023年甘肃积石山M_(S)6.2地震断层低速带研究  

Low-velocity fault zone of the 2023 Jishishan Gansu M_(S)6.2 earthquake based on linear dense array data

作　　者：吴柏辰 秦满忠[1,2] 郭晓 王亚红[2] 孙点峰 温淑琳 WU Baichen;QIN Manzhong;GUO Xiao;WANG Yahong;SUN Dianfeng;WEN Shulin(Lanzhou Institute of Seismology,CEA,Lanzhou 730000,Gansu,China;Gansu Lanzhou Geophysics Observation and Research Station,Lanzhou 730000,Gansu,China)

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]甘肃兰州地球物理国家野外科学观测研究站,甘肃兰州730000

出　　处：《地震工程学报》2024年第3期734-741,共8页China Earthquake Engineering Journal

基　　金：国家自然科学基金重点项目(42230305);甘肃省科技重大专项(21ZD4FA011);国家重点研发计划课题(2018YFC1503206)。

摘　　要：2023年12月18日,甘肃省积石山县发生M_(S)6.2逆冲型地震。该地震发生在祁连活动地块拉脊山北缘断裂带,在断裂两侧曾发生过20余次5级左右中强地震,地震活动频次高,因此研究拉脊山断裂带特征具有重要意义。根据拉脊山断裂走向和此次地震余震分布,在刘集乡布设一条线性密集台阵,利用不同方位的余震事件计算体波的走时延时和放大效应。结果表明,P波和S波分别存在6个采样点(约0.012 s)和15个采样点(约0.03 s)的走时延时,推断出台阵西侧存在一个约150 m宽近似垂直的断层低速带,且该结果与远震P波相似性系数矩阵结果一致。On December 18,2023,an M_(S)6.2 reverse-type earthquake struck Jishishan County,Gansu Province,along the northern margin of the Lajishan fault zone,Qilian active block.Given that over 20 M 5.0 earthquakes have occurred on both sides of the Lajishan fault,investigating its characteristics is paramount.Thus,based on the strike of the Lajishan fault and its aftershock distribution,we deployed a linear dense array in Liuji Town.Considering aftershock events in different directions,we determined travel time delays and amplification effects of body waves.The results identified six(approximately 0.012 s)and 15(approximately 0.03 s)sampling points of travel time delays for the P-and S-waves,respectively.This confirmed the presence of a nearly vertical low-velocity zone with a width of approximately 150 m along the west side of the array.The obtained results align with teleseismic P-wave similarity coefficient matrix calculations.

关 键 词：甘肃积石山M_(S)6.2地震 走时延时 体波放大效应 线性密集台阵 断层低速带 

分 类 号：P315[天文地球—地震学]