地磁低点位移异常与地震预测

Geomagnetic Low-Point Displacement Anomaly and Earthquake Prediction

利用国家地磁台网中心产出的观测资料,研究中国内地地区2013~2022年共10 a时间尺度的地磁低点位移异常与5级以上地震的关系。结果表明,地磁低点位移异常与5级以上地震之间具有较好的关联性,地磁低点位移异常出现后2个月内,其异常分界线300 km内发生5级以上地震的概率较大。2013~2022年中国内地地区共发生5级以上地震160次,异常对应率为32.4%,虚报率为67.5%,漏报率为48.1%,地震预测率为55.0%;46次地震前出现1次低点位移异常,42次地震前出现2次及以上异常。将地震前的多条低点位移异常分界线叠加到同一底图上,会形成1个或多个交汇区域,地震往往发生在低点位移分界线交汇区域。综合活动构造断裂分布、历史大地震情况、中长期预测强震潜在危险区及年度全国地震危险区等进一步研判发震区域,可大幅缩小地磁低点位移预测地震发生地点的范围。

Based on observation data from the National Geomagnetic Network Center,we study the relationship between the geomagnetic low-point displacement anomaly and earthquakes above 5 magnitude in the China's mainland in the 10 years from 2013 to 2022.The results show good correlation between the geomagnetic low-point displacement anomaly and earthquakes above 5 magnitude.There is high probability of earthquakes with magnitude greater than 5 within 300 km of the anomaly boundary within 2 months after the occurrence of geomagnetic low-point displacement anomaly.The results show that 160 main earthquakes with M_(S)≥5 occurred in China's mainland in 2013 to 2022,with an anomaly correspondence rate of 32.4%,the false alarm rate of 67.5%,the false negative rate of 48.1% and the earthquake prediction rate of 55.0%.There is one low-point displacement anomaly before 46 earthquakes,and two or more anomalies before 42 earthquakes.The study also found that superimposing multiple low-point displacement anomaly boundaries before an earthquake on the same base map will form one or more intersection areas,and earthquakes often occur in the intersection area of the low-point displacement boundary.Based on the distribution of active tectonic faults,the occurrence of historical large earthquakes,the potential danger zone of strong earthquakes predicted in the medium and long term and the annual national earthquake danger zone,we further judge the possible earthquake area.This study greatly reduces the range of earthquake location predicted by geomagnetic low point displacement method.