2020年7月12日唐山M_(S)5.1地震前后视应力变化  

Apparent Stress Changes before and after the Tangshan M_(S)5.1 Earthquake on July 12,2020

作　　者：王宁[1] 杨春利 王亚玲 王莉婵 李冬圣[1] 蔡玲玲[1] WANG Ning;YANG Chunli;WANG Yaling;WANG Lichan;LI Dongsheng;CAI Lingling(Hebei Earthquake Agency,Shijiazhuang 050021,China;China Mobile Construction Limited Company Hebei Branch,Shijiazhuang 050091,China)

机构地区：[1]河北省地震局,石家庄050021 [2]中移建设有限公司河北分公司,石家庄050091

出　　处：《华北地震科学》2021年第3期99-104,共6页North China Earthquake Sciences

基　　金：河北省地震局三结合课题(DZ20190422039);河北省地震局星火计划面上项(DZ20190422038);河北省地震局星火项目(DZ20180319008)。

摘　　要：2020年7月12日河北唐山发生M_(S)5.1地震,震中位置位于唐山老震区,是1995年之后唐山地区最大地震。选取河北台网监测到的2016年1月1日至2020年12月24日期间河北唐山地区M_(L)≥2.5地震,利用Brune模型,计算出震源区相应地震的视应力值,分析震源区应力调整过程;利用CAP和GPAT两种方法计算河北唐山M_(S)5.1地震震源机制解,并结合震源区附近地质构造分析其发震构造,结果显示:①地震前后视应力变化过程为主震前趋势升高—震时达到峰值—震后趋势下降;②主震发震断层为唐山-古冶断裂,错动方式为右旋走滑型。On July 12,2020,an M_(S)5.1 earthquake occurred in Tangshan,Hebei Province.The epicenter was located in the old earthquake area of Tangshan,and it was the largest earthquake in Tangshan region since 1995.The M_(L)≥2.5 earthquake recorded by Hebei Seismic Network from January 1,2016 to December 24,2020 in Tangshan area of Hebei Province was selected.The apparent stress value of the corresponding earthquake in the focal area was calculated by using the Brune model,and the stress adjustment process in the focal area was analyzed.Focal mechanism solution of Tangshan MS 5.1 earthquake is calculated by CAP and GPat methods,and the seismogenic structure is analyzed in combination with the geological structure near the focal area.The results show that:(1)the variation process of apparent stress before and after the earthquake is as follows:the trend increases before the main earthquake,the peak value during the earthquake,and the trend decreases after the earthquake.(2)The main seismogenic fault is Tangshan-Guye fault,and the dislocation mode is right-lateral strike-slip type.

关 键 词：视应力 唐山M_(S)5.1地震 震源机制解 

分 类 号：P315.63[天文地球—地震学]