河北及邻区地震类型特征及震后早期最大余震预估方法的研究  

Study on Characteristics of Seismic Sequence Types and Early Aftershock Prediction Method in Hebei and Its Surrounding Regions

作　　者：孙丽娜[1,2] 齐玉妍 张合[1] Sun Lina;Qi Yuyan;Zhang He(Hebei Earthquake Agency,Shijiazhuang 050021,China;Hebei Hongshan Natinona Observatory on Thick Sediments and Seismic Hazards,Xingtai 054000,Hebei,China)

机构地区：[1]河北省地震局,石家庄050021 [2]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

出　　处：《震灾防御技术》2025年第1期63-76,共14页Technology for Earthquake Disaster Prevention

基　　金：河北省地震科技星火计划项目(DZ2023120700001、DZ20200827054、DZ2023120700004、DZ2021121600019)。

摘　　要：本文梳理了河北及邻区(京津冀地区)1970年至2022年M_(S)≥3.5地震目录,对M_(S)≥3.5主震进行地震类型判定。研究发现,在该地震目录中,主余型地震66次,多震型地震24次,孤立型地震58次。本文对研究区内地震类型及其空间分布特征进行分析,并利用震级均值特性计算地震序列的最大余震震级,结果表明:(1)研究区域内的地震类型以主余型为主(45%),孤立型次之(39%),多震型最少(16%)。9次M_(S)≥5.0主震中,主余型3次,孤立型6次。随着震级增大,主余型地震所占比例也随之增加。(2)主余型地震序列和多震型地震序列中,最大余震在震后1 d内发生的占比最大。(3)地震类型的空间分布显示,3种类型的地震,沿着张家口—渤海地震带和河北平原地震带分布。孤立型地震在这2个条带上分布比较均匀;主余型地震主要分布在张家口、唐山、邢台一带;多震型地震与主余型地震分布情况基本相同。(4)利用震级均值特性,计算该区M_(S)≥5.0主震(主余型)的最大余震震级,发现3个研究震例计算得到的最大余震震级与实际记录比较相近,可以用此方法预估河北地区未来中强震的最大余震,为震后强余震的判断提供参考方法。This study reorganizes the earthquake catalog of M_(S)≥3.5 events from 1970 to 2022 in Hebei and its surrounding regions(Beijing-Tianjin-Hebei)and classifies the earthquake types of M_(S)≥3.5 main earthquakes.The analysis identifies 66 mainshockaftershock earthquakes,24 multiple-mainshock earthquakes,and 58 isolated earthquakes.The study examines the types and spatial distribution of earthquakes and estimates the maximum aftershock magnitude of earthquake sequences using the average magnitudes of aftershock sequences.The key findings are as follows:(1)Mainshock-aftershock earthquakes are the most prevalent(45%),followed by isolated earthquakes(39%)and multiple-mainshock earthquakes(16%).Among the M_(S)≥5.0 earthquakes(nine in total),three are mainshock-aftershock events,while six are isolated earthquakes.Additionally,the proportion of mainshock-aftershock earthquakes increases with earthquake magnitude.(2)In both mainshock-aftershock and multiple-mainshock sequences,the largest aftershocks predominantly occur within one day after the main event.(3)The spatial distribution of earthquake sequences reveals that all three earthquake types are concentrated along the Zhangjiakou-Bohai and Hebei Plain seismic belts.Isolated earthquakes are evenly distrib-uted across these belts,while mainshock-aftershock and multiple-mainshock earthquakes are mainly concentrated in Zhangjiakou,Tangshan,and Xingtai.(4)The maximum aftershock magnitude for M_(S)≥5.0 mainshock-aftershock earthquakes is estimated using the average magnitudes of aftershock sequences.The calculated values closely match observed data,indicating that this method can serve as a predictive tool for assessing the maximum aftershock magnitude of moderate to strong earthquakes in Hebei.This approach provides a valuable reference for evaluating the likelihood of strong aftershocks following seismic events.

关 键 词：地震类型 空间分布特征 震级均值 最大余震震级 

分 类 号：P315.9[天文地球—地震学] P315.7[天文地球—固体地球物理学]