基于构造活动的断层气汞异常探讨  

Discssion on fault product gas-mercury anomaly based on tectonic activity

作　　者：李冬梅[1,4] 杨静 常姣[3,4] 李丽[1,4] LI Dongmei;YANG Jing;CHANG Jiao;LI Li(Shanxi Earthquake Agency,Taiyuan 030021,China;Linfen Earthquake Monitoring Center Station,Shanxi Earthquake Agency,Shanxi Province 041000,China;Yuncheng Earthquake Monitoring Center Station,Shanxi Earthquake Agency,Shanxi Province 044400,China;National Continental Rift Valley Dynamics Observatory of Taiyuan,Taiyuan 030025,China)

机构地区：[1]山西省地震局,太原030021 [2]山西省地震局临汾地震监测中心站,山西041000 [3]山西省地震局夏县地震监测中心站,山西044400 [4]山西省太原大陆裂谷动力学国家野外科学观测研究站,太原030025

出　　处：《地震地磁观测与研究》2022年第4期61-72,共12页Seismological and Geomagnetic Observation and Research

基　　金：山西省应用基础研究计划面上青年基金(项目编号:201901D211549)。

摘　　要：利用2008—2017年夏县地震台断层气汞浓度观测数据,分析其异常变化与地震活动间的关联性,结合同时段震源机制解、库仑应力和由GPS基线推测的山西南部构造应力场、地壳形变特征,解释断层气汞浓度变化与区域构造活动间的关系。结果表明:①按照气汞浓度背景值变化幅度的不同,研究时段大致分为2010年10月—2011年7月、2013年3—12月、2015年1月—2017年5月等3个阶段,其中,第2、3阶段的背景值分别为第1阶段的8倍、60倍;②距测点200 km范围内4级左右地震发生前,气汞浓度往往表现为一组高值突跳变化,变化幅度高出平均背景值几倍至几十倍,震后很快降低至背景值附近;③气汞浓度趋势性上升和多组高值突跳变化、震源机制一致性参数高值、库仑应力积累、GPS压性作用增强和转折等,在时间上具有较好的准同步性,在空间上较吻合,表明夏县地震台断层气汞浓度异常与区域构造活动密切相关。Based on the fault gas mercury data at the Xiaxian Seismic Station from 2008 to 2017,we analyzed the correlation between its abnormal changes and seismic activity.Then the relationship between the fault gas mercury anomaly and regional tectonic activity is explained combined with the focal mechanism solution,coulomb stress,tectonic stress field and crustal deformation characteristics in southern Shanxi inferred from GPS baselines.The results show that:①According to the background value of gas mercury,the research period is roughly divided into three stages:October 2010-July 2011,March-December 2013,January 2015-May 2017,where the background values of the second and third stages are 8 times and 60 times that of the first stage,respectively;②Before an earthquake with magnitude around 4 within 200 km from the measuring point,the concentration of gaseous mercury often showed a group of high-value sudden changes,the amplitude of which was several to dozens of times higher than the average background value,and soon decreased to the background after the earthquake;③The increase of gas mercury concentration,the sudden change of multiple groups of high values,the high value of focal mechanism consistency parameters,the accumulation of Coulomb stress,the enhancement and turning point of GPS pressure,etc.,have a good quasi-synchronicity in time and a good agreement in space,indicating that the abnormal gas mercury concentration of the Xiaxian Seismic Station is closely related to the regional tectonic activity.

关 键 词：断层气汞浓度 映震特征 短临预报 

分 类 号：P315.7[天文地球—地震学]