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本文搜集了1976年7月28日至1979年12月31日期间唐山地震序列中所有M_s≥4.0地震的初动资料。这些资料来自于68个地震台的记录图和其它14个地震台的数据。其中,167次地震得到可靠的断层面解。对这些断层面解的分析表明,震源区介质中的应力经历了一个由震前紧张平衡态,经主震后的极不稳定态,逐渐向松驰平衡态演变的释放调整过程;对于余震区的不同部分,该过程存在着细节上的差异。两种平衡态下应力主轴的空间取向基本相同,这意味着制约唐山地区构造应力场的周围环境因素没有因发生唐山地震而改变。因此,该地区的构造运动将有继承性,而地震活动将会间歇性地重现。
This paper collected the initial data of all M_s≥4.0 earthquakes in Tangshan earthquake sequence from July 28, 1976 to December 31, 1979. The data come from the records of 68 seismostats and the data of 14 other seismostats. Of these, 167 earthquakes resulted in a reliable fault plane solution. The analysis of these fault plane solutions shows that the stress in the source region has undergone a release-adjustment process that gradually changes from the pre-earthquake tension equilibrium state to the post-earthquake extremely unstable condition and gradually releases to the relaxation equilibrium state. For the aftershock zone Different parts of the process, there are differences in the details. The spatial orientation of the stress spindles in the two equilibrium states is basically the same, which means that the environmental factors that constrain the tectonic stress field in the Tangshan area have not changed due to the Tangshan earthquake. Therefore, tectonic movements in this area will have inheritance, and seismic activities will be intermittently reproduced.