首页|2020年唐山古冶5.1级地震前后岩石圈磁场异常变化分析

2020年唐山古冶5.1级地震前后岩石圈磁场异常变化分析

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
  • 维普
基于唐山及周边地区2019年9月—2021年4月连续4期流动地磁观测资料,获得唐山地区岩石圈磁场异常变化模型,以此分析2020年7月12日唐山古冶5.1级地震前后半年期岩石圈磁场的时空变化特征.结果表明:(1)岩石圈磁场变化的水平矢量在地震前出现明显的方向转向和幅值弱化的现象,地震前后经历了"由震中向周边分散→由周边向震中汇聚发震→方向反转"的时空演化过程;(2)震中附近各测点岩石圈磁场总强度值在地震前后具有规律性时序变化,均呈现"震前缓慢减小→同震时期急剧增大→震后急剧减小"的特征;(3)基于压磁效应和断层亚失稳模型分析,地震前后岩石圈磁场异常的时空变化特征或许是由震中附近主要断裂地应力的积累和释放所致.
Variation of lithospheric magnetic field anomalies before and after the Guye,Tangshan MS5.1 earthquake in 2020
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.

Guye MS5.1 earthquakemobile geomagnetic surveylithospheric magnetic fieldspatiotemporal variation

张海洋、毛丰龙、王朝景、刘德强、李博

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河北红山巨厚沉积与地震灾害国家野外科学观测研究站,河北邢台 054000

河北省地震局保定地震监测中心站,河北保定 071000

古冶5.1级地震 流动地磁 岩石圈磁场 时空变化

河北省地震科技星火计划攻关项目河北省地震科技星火计划攻关项目河北省地震科技星火计划攻关项目河北省地震科技星火计划重点项目

DZ2021121600003DZ2021121400007DZ2023120800024DZ20190422046

2024

10.20000/j.1000-0844.20210709001

地震工程学报
中国地震局兰州地震研究所,中国地震学会，清华大学，中国土木工程学会

地震工程学报

CSTPCD北大核心
影响因子：1.191
ISSN：1000-0844
年,卷(期)：2024.46(1)
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