北京附近及其西部地区构造应力场与地震活动性分析

The Tectonic Stress Field and Seismicity in the Area Near Beijing and its West

一、引言北京及其西部地区(东经114—117°,北纬39—41°)是华北东西向活动构造带和北北东及南北向活动构造带汇交的地区之一,构造十分复杂,它又是主要地震带汇交的地区。历史上曾发生过破性地震若干次,著名的三河-平谷8级地震就在此地发生。近期研究区内小震活动频繁,地形变和地应力资料都表明该区的断裂仍在活动。1989年大同发生的6.1级地震就是断裂活动增强的信号。那么,首都北京及其附近地区在近几年或更长一些时间内是否会发生6级以上地震呢?为此,我们以现今构造应力场分析为主,结合地形变、小震活动、大震迁移来讨论该区的地震趋势。

The distributive features of current stress field are studied and the seismicity is analysed by the calculation of 2-d finite element method, and other related data analyses in the area. The Guanglin-Linqiu to the west and Sunhe-Daihuichang-Daixing to the east, and the region northeast of Huairou-Xiadian are firstly regarded as probable area of earthquake ocurrence.