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Title:: Application of First-Order Difference Method in the Extraction of Seismic Geomagnetism Precursor Signal

作者:: 袁桂平¹; 冯志生¹; 李鸿宇¹; 姜楚峰²; 潘颖¹; 钱庚²; 姚休义³; (1.江苏省地震局,江苏南京 210014; 2.湖北省地震局,湖北武汉 430071; 3.云南财经大学巨灾风险管理研究中心,云南昆明 650221)

Author(s):: YUAN Guiping¹; FENG Zhisheng¹; LI Hongyu¹; JIANG Chufeng²; (1.Jiangsu Earthquake Agency,Nanjing 210014,Jiangsu,China)(2.Hubei Earthquake Agency,Wuhan 430071,Hubei,China)(3.Catastrophic Risk Management Research Center,Yunnan University of Financeand Economics,Kunming 650221,Yunnan,China)

Keywords:: geomagnetism anomaly; total geomagnetic intensity; first-order difference; precursor anomaly

摘要:: 在探索震前地磁每日一值空间相关异常机理的基础上,利用2008—2018年130个台站地磁场数据计算地磁场总强度F每日一值一阶差分在空间上变化的不同步现象,并提取震前地磁异常。结果表明:当地磁场总强度F逐渐增大这一趋势变化出现不同步现象时,研究区内一阶差分值全正或者全负的正常状态会被打破,从而导致区域内出现各台站F每日一值一阶差分正、负值台站分布较为集中的现象,且正、负值台站之间出现明显的异常分界线(0值线),通过异常与对应震例统计,发现该异常发生后8个月内在0值线300 km附近有发生5级以上地震的可能性。

Abstract:: On the basis of exploring the spatial correlation anomaly mechanism of geomagnetism daily one-value before earthquake,using the total geomagnetic field data of 130 stations from 2008 to 2018,we calculated the spatial variation of the one-value first-order difference of the total geomagnetic field F and extracted the geomagnetic anomalies before earthquakes.The results show that when the non-synchronous phenomena on the gradual increase of F was appeared,the normal state of all positive or all negative difference values in the study area will be broken.As a result,there appreaed the distribution of positive and negative value stations whose the first order difference isoline of F daily value are more concentrated in the region,and there is an obvious abnormal boundary(zero value line)between positive and negative value stations.According to the statistics of anomalies and corresponding earthquake,it is found that there is the possibility of M≥5 earthquakes occurring within 8 months after the occurrence of the anomaly near 300 km of the zero line.