探讨水头增量及其变化率对水库诱发地震活动的影响——以紫坪铺水库为例

发布时间：2018-03-25 08:17

本文选题：紫坪铺水库　切入点：汶川地震　出处：《地震地质》2017年03期

【摘要】：分析水库蓄水在地震发生中的作用时,首先需要了解水在其中的扩散过程及其作用机理。文中通过紫坪铺水库蓄水后,汶川地震前的小震活动时空演化,探讨水库蓄水诱发地震活动的发生、发展过程及其机理。从比较地震时空分布和水体范围变化开始,进而探讨影响建模计算的各个因素,最后给出计算结果。得出以下几点认识:1)紫坪铺水库蓄水后到汶川地震发生前,水库周围的小震活动与水库蓄水密切相关,并且小震分布在汶川地震的地震断层上。2)受地形和介质的影响,水库影响范围实际上是有限的,并且是各向异性的。因此在建模计算前,半定量地获得了孔隙压力扩散系数,沿断裂走向和倾向分别为0.7m2/s和0.35m2/s;定性地设定了地表约束。3)计算结果表明紫坪铺水库附近地震活动的范围与孔隙压力增量有关。当应力值达到触发地震活动的阈值之后,不论水头增量是否处于高值,地震活动的兴衰皆受控于增量变化率。这表明孔隙压力对震群活动的触发是动态触发。
[Abstract]:In order to analyze the effect of reservoir water storage on earthquake occurrence, it is necessary to understand the diffusion process of water in the reservoir and its mechanism. In this paper, the temporal and spatial evolution of small earthquake activities before the Wenchuan earthquake is introduced through the Zipingpu reservoir. This paper discusses the occurrence, development process and mechanism of seismic activity induced by reservoir impoundment. It begins with the comparison of temporal and spatial distribution of earthquakes and changes of water body scope, and then discusses the factors affecting modeling and calculation. Finally, the calculation results are given. The following points are obtained: 1) after the Zipingpu reservoir was impounded and before the Wenchuan earthquake, the small earthquake activities around the reservoir were closely related to the reservoir water storage. And the distribution of small earthquakes on the earthquake fault of Wenchuan earthquake. 2) affected by topography and medium, the influence range of reservoir is actually limited and anisotropic. Therefore, the diffusion coefficient of pore pressure is obtained semi-quantitatively before modeling and calculation. The calculated results show that the range of seismic activity near Zipingpu Reservoir is related to the increment of pore pressure, and when the stress value reaches the threshold of triggering seismic activity, the calculation results show that, after the stress value reaches the threshold of triggering seismic activity, the calculation results show that the range of seismic activity near Zipingpu Reservoir is related to the increment of pore pressure. Whether or not the water head increment is at a high value, the rise and fall of seismic activity are controlled by the increment rate, which indicates that the triggering of pore pressure to earthquake swarm activity is dynamic.
【作者单位】：华北水利水电大学资源与环境学院;中国地震局地质研究所地震动力学国家重点实验室;
【基金】：国家自然科学基金(41572181) 中央级公益性科研院所基本科研业务专项(IGCEA1415) 华北水利水电大学高层次人才引进项目(40476) 中国地震局地震科技近期重点突破方向专项经费共同资助
【分类号】：P315.728

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