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本文对丹江口水库区地震活动的有利地质条件,海西期以来应力场,地震活动特点,成因与发展趋势都作了讨论。初步认为:丹江口地震活动区处在两组不同的构造线交汇,隆起断块与下降断块接触边缘,差异运动强烈地段以及不同类型岩石的接触部位。地震活动是在特殊水文地质环境下,由于北东东向压应力作用,两组剪切面在水的参与下发生滑动的结果。有利的地质条件是丹江口水库区地震活动的主因,库水引起的垂直压力和孔隙压力是次要因素。在发展趋势上,1973年11月29日4.7级地震可能就是157米水位线诱发的最高震级。二期工程竣工后,有可能发生5级左右的地震。这一看法,对充分利用丹江口水库使其发挥应有的作用,以及二期工程的进行都可能有一定的参考价值。
The favorable geological conditions of the seismic activity in the Danjiangkou reservoir area, the stress field since the Hercynian period, the characteristics, the causes and the development trend of the seismic activity are all discussed in this paper. It is preliminarily believed that the Danjiangkou seismic zone is located at the intersection of two groups of different tectonic lines, the contact edge between the uplift block and descending block, the strong differential motion section and the contact area of different types of rocks. Earthquake activity is the result of sliding in the two sets of shear planes with the participation of water in the special hydrogeological environment due to the NE pressure. The favorable geological conditions are the main cause of seismic activity in Danjiangkou reservoir area. Vertical pressure and pore pressure caused by reservoir water are secondary factors. On the development trend, the magnitude of 4.7 on November 29, 1973 may be the highest magnitude induced by the 157 m water level. After the completion of the second phase, about 5 earthquakes may occur. This view, to make full use of Danjiangkou reservoir to play its due role, as well as the second phase of the project may have some reference value.