首都圈的断层在唐山7.8级地震和大同阳高6.1级地震前后的活动特征

Fault Movement Characteristics Before and After the Tangshan (M=7.8) and the Datong-Yanggao(M=6.1)Earthquakse Beijing Area

一、引言自1967年在首都圈(N38°~41°、E113°~120°)建立跨断层测量点(台)监测断层的现今活动以来,对本区所发生的唐山7.8级地震和大同阳高6.1级地震以及部分M_s>4.5级地震均显示出较好的地震前兆异常活动,显然,在断层活动与地震活动之间有着密切相关的、内在的、机制上的联系.从构造地质学的角度来研究断层活动与强震的关系.

The mid-range trending anomalies in 2~3 years and the short-instant forerunner anomalies in one to several monthes of the faulting were found before the occurrences of Tahgshan earthquake in 1976 and Datong-yanggao earthquake in 1989 by analysing the spatial-temperal characteristics of the crossing fault base line data and the levelling data in Capital circal area?The range of the faulting forerunner anomaly was interretaled with the earthquake intensity to a certain degree.The results show that the faulting form were different between the above mentaind events,they were controlled by principal pressure stress in NW-SEE and NE-SW direc-tions respectively.