唐山地震的孕育与强震的增震作用

唐山地震的孕震构造是唐山菱形块体,在NEE向的区域应力场的作用下,最大剪应力集中在它的对角线上,正好与唐山断裂带相一致,因此成了唐山地震大破裂的始发点.唐山地震前兆演化过程中,有两个显著特点:在空间上有“震中→外围→震中+外围”的转移过程;在时间上有明显的阶段性,前兆异常频次的每一次加速都发生在外围强震发生之后,本文用强震的增、减震理论,推测外围强震的发生对唐山地震的孕育有强化作用,在一个大的区域,强地震的增、减震效应可以形成多个高应力集中区,这些高应力集中区多数都是未来发生强震的地区.

DEVELOPMENT OF THE TANGSHAN EARTHQUAKE AND THE EARTHQUAKE INCREASING ACTION OF STRONG EARTHAUAKE

The seismogenic structure of the Tangshan earthquake is the Tangshan rhombo-block, the maximum shear stress accumulated on its diagonal line under the action of NEE regional stress field, which is consitent with the Tangshan fault zone, so it became the initial beginning point of large fracture of the Tangshan earthquake. The evolution process of the precursors of the Tangshan earthquake showed two obvious characteristics: in space, they showed a transfer process from epicenter to outlying area to epicenter plus outlying area ; in time , showing obvious stages, each speedup of the frequency of precursory anomalies all occurred after accurence of a strong earthquake in outlying area. In this paper, the earthquake-increasing and earthquake-decreasing theory is used to infer the strengthening action to the development of the Tangshan earthquake by occurrence of strong earthquakes in outlying areas. In a large area, the earthquake-increasing and earthquake decreasing effect of strong earthquakes can form many high stress concentrated areas. Most of these high stress concentrated areas are the occurrence areas of the coming strong earthquakes.