冀鲁豫交界区流动地磁场总强度异常特征及地震活动性分析

Anomaly Variation of Mobile Geomagnetic Total Intensity and Seismicity Analysis in Juncture Area of Hebei,Shandong and Henan

运用2014年7月至2016年4月冀鲁豫交界区开展的流动地磁9期次测量资料,分析相邻期、半年期、一年期的地磁场变化特征。结果表明,除2015年11月、12月地磁场总强度相邻期异常变化较大外,其余期次的相邻期地磁场变化较小,在10nT左右;半年、一年尺度磁异常整体表现为上升。将范县附近8个测点磁异常变化与地震序列进行对比分析发现,磁异常变化梯度较大时,范县易发生小震群活动。

Variation characteristics of geomagnetic field in the adjacent period,half a year and one year are analyzed by the 9phases of mobile geomagnetic survey data in juncture area of Hebei,Shandong and Henan from July 2014 to April 2016.The results show that the anomaly variation of total geomagnetic intensity in the adjacent period is small except November 2015 and December 2015,and is maintained at about 10 nT.The magnetic anomalies of the half year and one year scale increase generally.By comparative analysis of magnetic anomalies of 8measuring points near Fanxian and earthquake sequence,it is found that small earthquake swarm activity is prone to occur in Fanxian when the magnetic anomaly gradient is large.