2020年唐山5.1级地震发震背景分析

The Seismogenic Background of the 2020 Tangshan M5.1 Earthquake

1976年唐山7.8级震后40多年,地处唐山断裂东北端点的古冶发生了2020年7月12日5.1级中强地震。本文综合构造背景、多年小震时空图像背景、多次地震的震源机制解结果,同时根据现场考察等资料以及前人相关研究成果,分析这次地震的多元发震背景。结果表明:此次地震发震断裂为与唐山断裂带共轭的抹轴峪断裂,未来该区域仍具有一定发震风险。通过此次研究,对唐山老震区孕震构造背景有了新的认识。

More than 40 years after the 1976 Tangshan earthquake of M7.8,an M5.1 earthquake still occurred on July 12,2020 in Guye located at the northeast end of Tangs-han fault.In this paper,the multiple seismogenic background of this earthquake is ana-lyzed by combining the tectonic background,the space-time image of many small earth-quakes,the result of focal mechanism solution of many earthquakes,on-site investigation and other data as well as previous research results.The results show that the seismic fault is the Mozhouyu fault which is conjugated with Tangshan fault zone,and there still exists a certain risk for future earthquake occurrence in this area.Through this study,a new un-derstanding of seismogenic tectonic background in the old Tangshan seismic area has been obtained.