RIS时空分布特征及其与库区地质构造环境的关系

在广泛收集了国内外水库诱发地震震例资料的基础上,利用统计学的方法,进行了水库诱发地震空间分布与时间响应特征及其与库区地质构造环境关系的研究,结果表明:①在空间分布上,诱发地震主要集中在水库周缘10 km范围之内,并局限于特定的库段丛集分布,当库区具备一定的地质构造与水文地质条件时,诱发地震活动会随着水库蓄、放水过程中的水位变化而发生迁移;②对于不同地区或不同水库,诱发地震活动的时间响应存在着差异,总体上:在水库蓄水后1年以内,初次响应占据一定的优势,而绝大部分诱发主震活动发生在水库初始蓄水1年以后。对长时间的水库蓄水历程而言,"混合响应"是水库诱发地震活动表现形式的主体,而"快速响应"和"滞后响应"仅是在一定的时间段内反应的阶段性现象;③诱发地震响应与水库水位变化的关系十分复杂多样,既存在正相关关系,又有负相关性,同时在某种程度上表现出了较高震级的水库诱发地震对水位变化速率的依赖;④水库诱发地震时空分布受发震库区地形地貌与局部地质构造条件、岩性条件、水文地质条件等方面的先存内因的控制,事实上,它们对水库诱发地震时空分布的控制作用并不是截然分开的,其间存在着相互依存、辩证统一的关系。

Spatial Distribution and Time Response Characteristics of the Reservoir-induced Seismicity and Its Relationships with Geological Structure Environment in the Reservoir Region

On the basis of the previous work and collections of the latest information on reservoir-induced seismicity, the spatial distribution and time response characteristics of RIS and its relationships with geological structure environment in the reservoir region had been studied by using the method of statistics, the results show that ① in the spatial distribution, RIS mainly concentrated in the range of 10 km away from the reservoir＆amp;nbsp;margin and confined to a particular segment of the reservoir. When a certain condition of geological structure and hydrogeological conditions are met in the reservoir region, the activities of RIS will migrate with the changes of water level during water storage and drainage. ② the time responses of RIS are different from region to region and from reservoir to reservoir. In general, RIS’s initial response is dominant when the reservoir is filled less than 1 year, while most of the main earthquakes of RIS occur in more than 1 year after the reservoir initial storage. The “mixture response” is the main form of RIS activities for the long process of reservoir storage, while the“rapid response” and “delayed response” are only a periodic phenomenon. ③RIS response has very complex and diverse relationships with the reservoir water level changes, which can be positive correlation or negative correlation, and higher magnitude of RIS shows certain dependence on the rate of water level changes. ④ RIS spatial and temporal distribution is controlled by the existing internal causes including local terrain features, geological structure, lithologic and hydrogeological conditions in the reservoir area. In fact, all these causes that influenc the spatial and temporal distribution of RIS are interdependent and dialectical united and can not be completely separated.