本文初步讨论了中国八次大地震(M_s≥7.0)前后区域地震活动的时空变化过程。在这些大地震前后区域地震活动可分为三个阶段:(Ⅰ)地震活动主要分布在远震源区内;(Ⅱ)活动迁移集中到震源区及近震源区内,接着,大地震发生;(Ⅲ)大地震发生之后,特别是早期强余震活动期过后,区域地震活动逐渐扩散到远震源区中去,扩散地点往往是(Ⅰ)阶段中不甚活动的地点。此外,(Ⅱ)阶段中区域地震活动的持续时间,以及(Ⅲ)阶段中地震活动开始向远震源区扩散的时间似乎和大震震级的大小无关。 最后,尝试应用地震包体理论和大震后区域应力场调整的研究结果去理解上述大震前后区域地震活动的聚散过程。 研究大地震前后区域地震活动的特征,是探讨地壳地震的物理力学过程的一个重要途径。石田和金森博雄曾详细评述过强震前地震平静、前兆震群和地震簇集的图象。邱群等注意到唐山大地震前区域地震活动向未来震源区及其附近集中迁移的现象。作者曾指出过我国八次七级以上大地震前皆显示出区域地震活动的迁移过程。大地震发生之后,茂木曾研究过余震活动在震源区内扩散的特征。苏联卡托克曾报导过强震后区域地震活动沿断裂扩散的现象。本文将讨论大地震前后区域地震活动集中和扩散的过程和特征,并应用地震包体理论和应力调整的研究结果,去 In this paper, the spatial and temporal variations of seismic activity before and after the eight large earthquakes in China (M_s≥7.0) are discussed tentatively. The seismic activity before and after these large earthquakes can be divided into three phases: (1) the seismic activity is mainly distributed in the teleseismic source area; (2) the activity migration concentrates in the source area and the near source area, followed by the occurrence of a large earthquake; Ⅲ) After the occurrence of the major earthquakes, especially after the active period of the early strong aftershocks, the regional seismic activity gradually diffused into the teleseismic source areas, and the sites of diffusion were often the less active sites in stage (Ⅰ). In addition, the duration of regional seismic activity in Stage (II) and the onset of seismic activity in (III) to the source region of the far-focal point appear to be independent of the magnitudes of the earthquakes. Finally, we try to understand the convergence process of seismic activity before and after the above-mentioned large-scale earthquake by applying the research results of the earthquake inclusion body theory and the regional stress field adjustment after the earthquake. Studying the characteristics of seismic activity before and after a large earthquake is an important way to explore the physical and mechanical processes of crustal earthquakes. Ishida and Mori Mori have reviewed in detail the images of quake-prone earthquakes, precursory earthquake swarms and earthquake clusters before the strong earthquakes. Qiu et al. Noted that the regional seismic activity in the area prior to the Tangshan earthquake concentrated and migrated toward the source area and its vicinity in the future. The author has pointed out that before the eight major earthquakes of more than or equal to eight in our country, the process of the relocation of regional seismic activity has been shown. After the great earthquake, Motegi studied the characteristics of aftershock activity spreading in the focal area. The Soviet Union Cato has reported the regional seismic activity after the strong earthquake spread along the fault phenomenon. This paper will discuss the process and characteristics of the regional seismic activity concentration and diffusion before and after the major earthquake. Based on the findings of the seismic inclusion theory and stress adjustment,