甘肃张掖M_(S)5.0地震前山丹地电异常探讨  

Geoelectric Anomalies at Shandan Station before the Zhangye M_(S)5.0 Earthquake in Gansu Province

作　　者：杨兴悦 王燕 张俏丽 高振生 李亮 YANG Xingyue;WANG Yan;ZHANG Xiaoli;GAO Zhensheng;LI Liang(Lanzhou National Observatory of Geophysics, Lanzhou 730000, Gansu, China)

机构地区：[1]兰州地球物理国家野外科学观测研究站,甘肃兰州730000

出　　处：《地震工程学报》2021年第2期296-305,共10页China Earthquake Engineering Journal

基　　金：甘肃省地震局科技发展基金野外站项目(2018Y01)。

摘　　要：2019年9月16日在甘肃省张掖市甘州区发生M_(S)5.0地震,震前山丹地电阻率和地电场观测资料出现了较为明显的短临异常,震中距63 km。本文对该异常进行分析总结,排除周围观测环境,观测系统,自然环境,磁暴等因素外,认为该异常是较为可信的地震前兆异常。地电阻率观测资料异常形态NS测道表现为转折快速上升-缓慢下降,EW测道为转折缓慢上升,N45°W测道为缓慢下降-转折缓慢上升。地电场观测资料异常形态长极距NS道、长极距N45°E道、短极距NS道表现为转折同步缓慢上升,长极距EW道和短极距EW道转折同步缓慢下降,短极距N45°E道异常不明显。地震在异常持续过程中出现转折变化或上升(下降)速率发生改变时发生。The middle section of Qilian Mountains is considered to be a key area where strong earthquakes might occur in recent years,but the earthquake situation in the study area is still unclear.Therefore,it is of great practical significance to study the anomaly characteristics of geoelectric observation data recorded by Shandan station in Zhangye City,Gansu Province.On September 16,2019,an M_(S)5.0 earthquake occurred in Ganzhou District,Zhangye City,Gansu Province.Before the earthquake,there were obvious short-impending anomalies in the observation data of Shandan earth resistivity and geoelectric field,with an epicenter distance of 63 km.In this paper,the anomalies were analyzed and summarized,and they were considered to be reliable earthquake precursor anomalies after excluding the surrounding observation environment,observation system,natural environment,magnetic storm,and other factors.The abnormal forms of earth resistivity and geoelectric field observation data in different channels were also discussed.It is found that the earthquake occurred when the above-mentioned observation data had a turning change or the rising(falling)rate changed during the anomaly duration.

关 键 词：张掖地震 地电异常 地电阻率 地电场 

分 类 号：P315[天文地球—地震学]