河北及邻区震前岩石圈磁场异常变化分析  

Anomalous variation of the lithospheric magnetic field before earthquakes in Hebei and the adjacent areas

作　　者：张海洋 李博[1] 刘德强 王朝景 赵慧琴[1] 毛丰龙 苏树朋[1] ZHANG Haiyang;LI Bo;LIU Deqiang;WANG Zhaojing;ZHAO Huiqin;MAO Fenglong;SU Shupeng(Baoding Earthquake Monitoring Center Station,Hebei Earthquake Agency,Baoding 071000,Hebei,China)

机构地区：[1]河北省地震局保定地震监测中心站,河北保定071000

出　　处：《地震工程学报》2023年第1期191-198,共8页China Earthquake Engineering Journal

基　　金：河北省地震科技星火计划重点项目(DZ20190422046);中国地震局监测、预报、科研三结合课题(3JH-202001012);河北省地震科技星火计划青年项目(DZ202108090029)。

摘　　要：利用河北及邻区2018、2019和2020年3期流动地磁矢量资料,经数据处理获得了“2018—2019”和“2019—2020”2期岩石圈磁场年变化模型。并结合2019年12月唐山丰南4.5级地震和2020年7月唐山古冶5.1级地震震中分布,对震中区域岩石圈磁场变化空间分布及时间演化特征进行了系统分析。研究结果显示:2期岩石圈磁场年变化空间分布并无一致性或继承性特征,相对于“2018—2019”岩石圈磁场,“2019—2020”岩石圈磁场各要素的年变化量呈现减小的趋势。2019年12月唐山丰南4.5级地震和2020年7月唐山古冶5.1级地震前,震中附近岩石圈磁场呈现明显异常变化。具体表现为:震中附近岩石圈磁场水平矢量均存在局部弱化和转向的现象;震中处有磁偏角“0”值线和高梯级带通过。这可能是两次地震的前兆异常。Based on the mobile geomagnetic observation data of Hebei and its adjacent areas in 2018, 2019, and 2020, the annual variation model of the lithospheric magnetic field in “2018-2019” and “2019-2020” was obtained. In combination with the epicenter distribution of the Fengnan M4.5 earthquake in December 2019 and the Guye M5.1 earthquake in July 2020 in Tangshan, the spatial distribution and time evolution characteristics of changes in the lithospheric magnetic field of the epicentral area were systematically analyzed. Results show that there is no consistency or inheritance in the spatial distribution of annual changes of the 2-term lithospheric magnetic field. Compared with the “2018-2019” lithospheric magnetic field, there has been a decreasing trend in the annual change of various elements of the “2019-2020” lithospheric magnetic field. Before the two earthquakes above, there have been obvious anomalies in the lithospheric magnetic field near the epicenter. Specifically, the horizontal vector of the lithospheric magnetic field appears as a local weakening and results in direction changes with a zero-value line and high cascade zone through the epicenter area, which may be the preceding anomalies for the two earthquakes.

关 键 词：河北及邻区 流动地磁 岩石圈磁场 地震活动 前兆异常 

分 类 号：P319.56[天文地球—固体地球物理学]