三峡水库地震孕震机理与未来地震趋势初探

The study of Three Gorges Reservoir earthquake-fertilized mechanism and earthquake inducted by impoundment

以三峡库区区域地质构造、活动断裂及库区水文地质特点为基础,借鉴老一辈地震工作者对三峡地区地震地质活动的勘察与科研成果,阐述了蓄水后岩石的库水与地质相互作用对该区水文地质及构造的影响,浅释了三峡库区水库地震孕震机理;用三峡遥测台网及宜昌台定点地壳形变手段在蓄水前后的监测资料,对三峡宜昌库区水库诱发地震作了初步探讨及趋势分析。研究显示,库区地震活动的时空强频随着库区水体的变化而增强,并与活动断层空间分布呈一致性,具备水库地震的明显特征。预测认为:未来三峡宜昌库区的巴东-黔江与高桥断裂带、仙女山、九湾溪及天阳坪断裂交汇带,是诱发ML4.0～4.5水库地震的危险区。

On the basis of geological structure, fault movements and hydrological characteristics and in reference to many achievements in scientific research and explorations of seismic movements in Three Georges reservoir area, this article expounds the effects from the interaction between the water in the rocks in the reservoir on the hydrogeology and structure in this area and interprets the chances of earthquake in Three Georges reservoir area. Accordingly, Simply explanation the earthquake-fertilized mechanism of three gorges area;we make an initial inquiry and analysis to earthquake tendency in Yichang reservoir area relying on the observation data before and after retaining water in the reservoir from the Three Georges telecontrolled and interconnected seismological observing stations and the fixed crustal-deformation-observing stations in Yichang. The research shows that the time,space,intensity and frequency of the earthquake in this area increase with the changes of the waters that fault zones go with simultaneously. Possess the obvious characteristic of the earthquake of the reservoir. We pre- dict that the reservoir earthquakes at Mr. 4. 0 - 4. 5 will most possibly occur in such fault zones as Xiannv Mountain fault zone where Badong-Qianjiang and northwestern fault zones meet,and the one where Gaoqiao, Xiannv Mountain, Jiuwan Stream and Tianyangping fault zones meet.