唐山老震区M≥4.0地震前b值变化异常特征研究
Anormalies of b-value Changes before M≥4.0 Earthquake in Tangshan Old Seismic Region
岳晓媛 1李艳娥 2钟世军 1王薇 1王燕 1马梁1
作者信息
- 1. 北京市地震局,北京 100080
- 2. 中国地震局地球物理研究所,北京 100081
- 折叠
摘要
选取2009年1月至2022年12月唐山老震区的地震目录资料计算b值,利用格点搜索法确定b值下降幅度较大(≥20％)的区域作为异常区,分析该区域b值的时间变化特征,结合b值的时空变化研究该区域发生M4.0以上地震的危险性.研究发现,唐山老震区7次(组)M4.0以上地震均发生在b值下降幅度较大的区域边缘或附近,表明应力较高的区域是地震危险区.异常区域内b值的时间变化显示,7次(组)M4.0以上地震多在震前半年至一年出现b值下降的变化过程,也反映了异常区域应力逐渐积累的过程.总体来说,b值的时空下降变化对唐山老震区M4.0以上地震的研判具有指示意义.
Abstract
We select the data of earthquake catalogue from January 2009 to December 2022 in Tangshan old seismic region to calculate the b-value.The lattice searching method is used to determine the abnormal area with a significantly decrease in b-value(≥20％),the time variation characteristics of the b-value in this area are analyzed,the risk of M≥4.0 earthquakes in the area is studied based on the b-value spatiotemporal variation characteris-tics.The research has found that 7 M≥4.0 earthquakes occurred at or near the edges of areas with significantly decrease in b-values in the Tangshan old earthquake area,which indicates that areas with high regional stress are high-risk areas for earthquake occurrence.According to the time changes of b-values in the abnormal area,most of the 7 M≥4.0 earthquakes(groups)experienced a decrease in b-values from half a year to one year before the earthquake,which also reflects the gradual accumulation of stress in the abnormal area.The b-value decrease in time and space has indicative significance for the study and judgment of M≥4.0 earthquakes in the Tangshan old seismic region.
关键词
唐山老震区/异常特征/b值/格点搜索Key words
Tangshan old seismic region/Anomalous characteristics/b-value/Lattice searching引用本文复制引用
基金项目
北京市地震局科技项目(BJWC-2023013)
出版年
2024
NETL
NSTL
万方数据