玛多7.4级地震后库赛湖-玛曲-荷叶断裂活动性分析  

Tectonic activity analysis of Kusai Lake-Maqu-Heye Fault after Maduo M7.4 earthquake

作　　者：陈晓龙 蒲举 陈继锋 尹欣欣 张胜霞 王维欢 CHEN Xiaolong;PU Ju;CHEN Jifeng;YIN xinxin;ZHANG Shengxia;WANG Weihuan(Earthquake Administration of Gansu Province, Lanzhou 730000, China;Lanzhou National Observatory of Geophysics, Lanzhou 730000, China;Lanzhou Institute of Geotechnical and Earthquake, China Earthquake Administration, Lanzhou 730000, China)

机构地区：[1]甘肃省地震局,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 [3]中国地震局兰州岩土地震研究所,甘肃兰州730000

出　　处：《世界地震工程》2021年第4期21-27,共7页World Earthquake Engineering

基　　金：甘肃省地震局地震科技发展基金面上项目(2021M6);甘肃省青年科技基金计划项目(21JR7RA797)。

摘　　要：青海玛多M_(s)7.4级地震发生后,与此次地震发震断裂相邻且近平行状分布的库赛湖-玛曲-荷叶断裂(以下简称“库-玛-荷断裂”)截至2021年6月1日共发生5次M_(s)≥3.0的余震事件。本文分别计算了该断裂上震级较大的4次余震事件震源机制解,并对玛多M_(s)7.4级地震进行了静态库伦破裂应力改变量(ΔCFS)分析。结果显示:库-玛-荷断裂占主导地位的左旋走滑运动并没有简单延伸贯通,断裂带各段枢纽处应力分布错综复杂,断裂总体受到来自玛多震中方向的应力扰动。结合前人研究,本文认为库-玛-荷断裂上发生的一系列余震事件可视为该断裂带的应力释放过程。虽然玛曲-玛沁段最后一次大地震离逝时间已经超出或接近其复发周期,但在该断裂整体应力得到一定程度释放的前提下,大地震复发周期是否发生改变值得进一步探讨。After the Maduo M_(s)7.4 earthquake,there are 5 M_(s)≧3.0 aftershocks was occurred on Kusai Lake-Maqu-Heye Fault,which is located at north-northeast of the Maduo M_(s)7.4 earthquake epicenter.The focal mechanism solutions result of four aftershocks show that the whole movement of the fault is characterized by left lateral strike slip,but it is discontinuous,the stress distribution in each section of the fault zone is complicated.Combined with the Coulomb fracture stress distribution of Maduo M_(s)7.4 earthquake,we consider these aftershocks occurred on the Kusai Lake-Maqu-Heye Fault can be regarded as a stress release process.Although there are some studies suggest that the recurrence period of great earthquake is approached judged by historical experience,we still believe the recurrence period of this fault may have changed after the Maduo M_(s)7.4 earthquake.

关 键 词：玛多M_(s)7.4级地震 库赛湖-玛曲-荷叶断裂 地震复发周期 

分 类 号：P315.3[天文地球—地震学]