2019年长宁M6.0和2018年兴文M5.7地震引起的井水位同震响应对比分析

doi:10.12196/j.issn.1000-3274.2020.02.012

摘要/Abstract

摘要： 2019年长宁M6.0地震和2018年兴文M5.7地震引起了华蓥山断裂及其附近区域8口观测井水位不同程度的响应变化。本文对比分析各观测井水位的同震响应特征, 从地震波能量密度、同震破裂体应变、含水层渗透性参数变化以及断裂带控制作用几个方面探讨了其同震响应机理。结果显示, 井水位同震响应的幅度与地震波能量密度有一定关系; 2019年长宁M6.0地震引起的井水位同震响应形态符合同震破裂体应变四象限空间分布特征, 但2018年兴文M5.7地震则不符合; 两次地震引起的含水层渗透性参数变化存在空间上的不一致性和单点各向异性, 并且断裂带自身的水文条件对井水位同震响应形态和幅度有一定的控制作用。综合分析认为, 目前已有的几种机理无法完全解释两次地震引起的井水位同震响应现象。

关键词: 井水位, 同震响应, 华蓥山断裂, 渗透率

Abstract: 2019 Changning M6.0 and 2018 Xingwen M5.7 earthquakes caused water level changes in different degrees in eight wells around Huayingshan fault zone. Coseismic water level response in each well were analyzed from the aspects of the seismic wave energy density, coseismic volumetric strain, aquifer permeability change and control of fault zone, in order to find the mechanism of the response of well water level. The results show that the coseismic response amplitude of well water level is related to the energy density of seismic wave. The coseismic response type of water level caused by Changning M6.0 earthquake conforms to the four-quadrant spatial distribution of volumetric strain, but not that of Xingwen M5.7 earthquake. The aquifer permeability changes caused by two earthquakes are spatially inconsistent and anisotropy in each point. The hydrologic conditions of the fault zone have a certain control effect on the coseismic shape and amplitude of water level. As a result, it is concluded that several existing mechanisms cannot fully explain the coseismic response of well water caused by the two earthquakes.

Key words: Well water level, Coseismic response, Huayingshan fault zone, Permeability

中图分类号:

P315.7

向阳, 孙小龙, 杨朋涛, 张磊, 巩浩波. 2019年长宁M6.0和2018年兴文M5.7地震引起的井水位同震响应对比分析[J]. 地震, 2020, 40(2): 155-165.

XIANG Yang, SUN Xiao-long, YANG Peng-tao, ZHANG Lei, GONG Hao-bo. Comparative Analysis of Coseismic Well Water Level Response Caused by 2019 Changning M6.0 and 2018 Xingwen M5.7 Earthquakes[J]. EARTHQUAKE, 2020, 40(2): 155-165.

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