中国大陆岩石圈震磁异常年变统计分析  

Statistical Analysis of the Annual Variation of the Lithospheric Seismomagnetic Anomaly in Chinese Mainland

作　　者：蔡苏苏 陈斌[1] CAI Susu;CHEN Bin(Institute of Geophysics,China Earthquake Administration,BeijinglQOOSl,China)

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地震研究》2022年第4期592-598,共7页Journal of Seismological Research

基　　金：中国地震局地球物理研究所基本科研业务费专项(DQJB22B20)资助。

摘　　要：根据2010—2020年中国大陆岩石圈磁场年变数据与M_(S)≥6.0地震事件,按照0.5°×0.5°网格筛选出震前1年震中所处的网格中心点所对应的地磁要素进行对比分析。结果表明:(1)2011—2012年M_(S)≥6.0地震往往发生在磁偏角D、总强度F、垂直分量Z的零变线附近,但其梯度等值线图特征不显著。(2)2010—2020年M_(S)≥6.0地震共15次,D值在±0.5’之间的震例占比40%,F值在±4 nT之间的震例占比53.33%,Z值在±6 n T之间的震例占比53.33%;66.67%的震例分布在磁偏角梯度值为0.5~1’/°的地区,仅13.33%的震例分布在总强度梯度值为8~10 nT/°的地区,6.67%的震例分布在垂直分量梯度值为8~10 n T/°的地区。(3)水平矢量模|P_(f)|分布在10~12 n T、梯度在8~10 n T/°的震例占比分别为:20.00%、26.67%;矢量模|P_(f)|分布在12~14 nT、梯度在8~12 n T/°的震例占比分别为26.67%、20.00%。We select 15 eartqhuakes(M_(S)≥6.0)and the annual variation data of the lithospheric magnetic field in Chinese mainland from 2010 to 2020,and on the scale of 0.5°×0.5°grid,we screen the magnetic components corresponding to the grid centers where the earthquake epicenter is located.The results show:(1)These earthquakes usually occur near the zero-variation line of the magnetic declination D,total intensity F,and vertical component Z.However,the characteristics of their gradient contour map are not significant.(2)Among these 15eartqhuakes,there are 40%corresponding to the annual variation rate between-0.5’and+0.5’of the magnetic declination D.There are 53.33%corresponding to the total intensity F between-4 n T and+4 n T.There are53.33%correspoding to the vertical component Z between-6 n T and+6 n T.There are 66.67%events occurring in the areas in which the gradient value of the magnetic declination D is from 0.5’/°to 1’/°.There are only 13.33%events occurring in the areas in which the gradient values of the total intensity F are from 8 n T/°to 10n T/°.(3)There are 20.00%events corresponding to the horizontal vector norm|P|from 10 n T to 12 n T.There are 26.67%events corresponding to gradient values from 8 n T/°to 10 n T/°.There are 26.67%events corresponding to the vector norm|P_(f)|from 12 n T to 14 n T.There are 20.00%events corresponding to the gradient of the vector norm from 8 n T/°to 12 n T/°.

关 键 词：地震统计 岩石圈磁场 年度变化 磁异常 梯度 

分 类 号：P318.2[天文地球—固体地球物理学]