粤桂琼流体台网对区域中强地震的映震能力分析  

Analysis of Seismic Reflection Ability of the Guangdong, Guangxi, Hainan Fluid Network to Regional Moderate-strong Earthquakes

作　　者：廖丽霞[1] 林稚颖 莫佩婵 田雷 LIAO Lixia;LIN Zhiying;MO Peichan;TIAN Lei(Fujian Earthquake Agency,Fuzhou 350001,Fujian,China;Guangxi Zhuang Autonomous Region Earthquake Agency,Nanning 530022,Guangxi,China;China Earthquake Networks Center,Beijing 100045,China)

机构地区：[1]福建省地震局,福建福州350001 [2]广西壮族自治区地震局,广西南宁530022 [3]中国地震台网中心,北京100045

出　　处：《地震研究》2022年第2期290-299,共10页Journal of Seismological Research

基　　金：中国地震局地震科技星火计划攻关项目(XH21013);中国地震局震情跟踪定向工作任务(面上2021020301);国家重点研发计划专题(2019YFC1509404-4)联合资助。

摘　　要：对广西2016年苍梧5.4级地震、2019年靖西5.2级地震、2019年北流5.2级地震震中300 km范围内粤桂琼流体台网观测资料进行梳理,认为该台网最显著的映震特征是趋势性和群体性,具体表现为同一条断裂带或同一组平行的断裂带上多井水位出现同步(或准同步)长期的背景性趋势异常、中期的年动态畸变异常和震前半年的高水位异常,且水位年动态畸变与累积重力异常呈现出时间上的同步性、空间上的叠加性。含水层水文地质参数计算及水位应力反演显示,3次地震前压力增强、孔隙度减小、渗透系数增大、水位上升,均符合水文动力学机制,表明粤桂琼流体台网能够真实反映区域应力场的变化,震前水位年动态畸变及加速上升是区域应力增强的表征。综合分析认为粤桂琼流体台网对区域中强地震反映灵敏,具备较好的映震能力。By analyzing the fluid observation data of the Guangdong, Guangxi, Hainan fluid network within 300 km of the epicenter of the Cangwu M_(S)5.4 earthquake, the Jingxi M_(S)5.2 earthquake and the Beiliu M_(S)5.2 earthquake, it is considered that the most significant seismic reflection characteristics of the network are trend and group, which are specifically manifested in the long-term background trend anomaly of synchronous(or quasi synchronous)water level of multiple wells on the same fault zone or the same group of parallel fault zones.The annual dynamic variation anomaly in the middle period and the high water level anomaly in the first half year before the earthquake, and the annual dynamic variation of water level and cumulative gravity anomaly show synchronization in time and superposition in space.The calculation of hydrogeological parameters of aquifer and the inversion of water level stress show that the pressure increases, the porosity decreases, the permeability coefficient increases and the water level rises before the three earthquakes, which are in line with the hydrodynamics mechanism.It shows that the water level observation network of Guangdong, Guangxi and Hainan can truly reflect the change of regional stress field.The annual dynamic distortion and accelerated rise of water level before the earthquake are the characteristics of regional stress enhancement.The comprehensive analysis shows that the water level observation network of Guangdong, Guangxi and Hainan is sensitive to medium-strong earthquakes in this area and has good seismic reflection ability.

关 键 词：粤桂琼流体台网 水位年动态畸变 趋势异常 映震能力 苍梧5.4级地震 靖西5.2级地震 北流5.2级地震 

分 类 号：P315.723[天文地球—地震学]