由许多断层面解得到的等效应力场的统计结果,可以认为即代表了该区域的应力场。华北地区震源机制结果,显示出两个最大剪切应力方向的一致性,说明该区域处于统一的应力场中。唐山地震前后,区域应力场发生了什么变化,是人们关心的问题。本文从较大的范围,较宽的时间尺度,以小地震资料得到的综合断层面解,来探讨京津唐张地区区域应 The statistical results of equivalent stress field obtained from many fault planes can be considered as representing the stress field in this region. The focal mechanism results in North China show a consistent direction of the two maximum shear stresses, indicating that the region is in a uniform stress field. Before and after the Tangshan earthquake, what happened to the regional stress field is a matter of concern. In this paper, the comprehensive fault surface solution obtained from small seismic data from a large area, a wide time scale,