地震工程学报2024，Vol.46Issue(1)：224-231,240,9.DOI:10.20000/j.1000-0844.20210709001
2020年唐山古冶5.1级地震前后岩石圈磁场异常变化分析
Variation of lithospheric magnetic field anomalies before and after the Guye,Tangshan MS5.1 earthquake in 2020
摘要
Abstract
Based on the mobile geomagnetic data of Tangshan and its adjacent areas obtained from September 2019 to April 2021,we construct the variation model of the lithospheric magnetic field anomaly in the Tangshan area and analyze the spatiotemporal variation characteristics of the litho-spheric magnetic field before and after the Guye MS5.1 earthquake on July 12,2020.The results show the following:(1)There is a shift in the direction of the horizontal lithospheric magnetic field variation and an obvious decrease in its amplitude before the earthquake;before and after the earthquake,the lithospheric magnetic field experiences a spatiotemporal evolution process of"dispersing from the epicenter to the periphery→gathering from the periphery to the epicenter→reversing its direction."(2)The total intensity of the lithospheric magnetic field at measurement points near the epicenter varies regularly in time and sequence,exhibiting the characteristic of"slowly decreasing before the earthquake→sharply increasing during the coseismic period→sharp-ly decreasing after the earthquake."(3)Based on the piezomagnetic effect analysis and the meta-instability model of the fault,we consider that the spatiotemporal variation of the lithospheric magnetic field anomalies before and after the earthquake is caused by the accumulation and release of the in-situ stress of the main faults near the epicenter.关键词
古冶5.1级地震/流动地磁/岩石圈磁场/时空变化Key words
Guye MS5.1 earthquake/mobile geomagnetic survey/lithospheric magnetic field/spatiotemporal variation分类
天文与地球科学引用本文复制引用
张海洋,毛丰龙,王朝景,刘德强,李博..2020年唐山古冶5.1级地震前后岩石圈磁场异常变化分析[J].地震工程学报,2024,46(1):224-231,240,9.基金项目
河北省地震科技星火计划攻关项目(DZ2021121600003,DZ2021121400007,DZ2023120800024) （DZ2021121600003,DZ2021121400007,DZ2023120800024）
河北省地震科技星火计划重点项目(DZ20190422046) （DZ20190422046）
