华南地区地磁加卸载响应比异常指标  

Anomaly Index System of Geomagnetic Load-Unloading Response Ratio in South China

作　　者：倪晓寅[1] 郭雨帆 谢小玲[3] 刘吉平[4] 阎春恒 童敏 NI Xiaoyin;GUO Yufan;XIE Xiaoling;LIU Jiping;YAN Chunheng;TONG Min(Fujian Earthquake Agency,Fuzhou 350003,China;Jiangxi Earthquake Agency,Nanchang 330039,China;Hainan Earthquake Agency,Haikou 570203,China;Guangdong Earthquake Agency,Guangzhou 510070,China;Earthquake Agency of Guangxi Zhuang Autonomous Region,Nanning 530022,China;Hunan Earthquake Agency,Changsha 410004,China)

机构地区：[1]福建省地震局,福州350003 [2]江西省地震局,南昌330039 [3]海南省地震局,海口570203 [4]广东省地震局,广州510070 [5]广西壮族自治区地震局,南宁530022 [6]湖南省地震局,长沙410004

出　　处：《华南地震》2018年第4期22-28,共7页South China Journal of Seismology

基　　金：中国地震局震情跟踪专项工作任务(2017010405)

摘　　要：计算了2008—2016年华南地区的地磁加卸载响应比,分析研究了华南地区加卸载响应比异常特征和震例,提出了适用于华南地区的异常指标。研究结果表明:华南地区4级以上震例均发生在加卸载响应比异常出现后半年内,震中位于异常日加卸载响应比阈值等值线附近。分析推测加卸载响应比异常的形成机理与低点位移异常类似,都是由地下感应电流在电流两侧的反相位感应磁场引起的。This paper calculates the geomagnetic load-unload response ratio by using the data at geomagnetic stations in south China, analyzes the characteristics of anomalies and the earthquake cases, and finally presents the index system fitting to the analytic prediction in south China. The result shows that all earthquake cases with M≥4 in south China occurred within 6 months after the anomalies appeared, and most of these earthquakes were located near the threshold line of geomagnetic load-unloading response ratio at abnormal days. The paperspeculated that the geomagnetic load-unload response ratio anomalies were caused by the induced current underground which caused opposed-phase induced magnetic field on opposite sides of the current, and this formation mechanism is similar with the geomagnetic low point displacement anomaly.

关 键 词：地磁 垂直分量 日变化 加卸载响应比 异常指标 

分 类 号：P315.721[天文地球—地震学]