2022年河北磁县震群与重力场动态变化  

Analysis of Earthquake Swarm and the Dynamic Change of Gravity Field in Cixian,Hebei Province in 2022

作　　者：杨雅慧 张纳莉[1] 刘洪良[1] 张展伟 昝书林 YANG Yahui;ZHANG Nali;LIU Hongliang;ZHANG Zhanwei;ZAN Shulin(Baoding Central Seismic Station,Hebei Earthquake Agency,Baoding,Hebei 071000,China)

机构地区：[1]河北省地震局保定地震监测中心站,河北保定071000

出　　处：《华北地震科学》2024年第4期102-105,共4页North China Earthquake Sciences

基　　金：河北省地震科技星火计划项目(DZ2024112000005)。

摘　　要：基于河北南部地区流动重力观测数据,研究2022年8—9月期间磁县震群前后该区域重力场的动态变化特征。结果表明:①本次磁县震群孕育发震对应的显著重力动态变化特征为持续的正重力变化及重力变化梯度带,符合现有的震前典型重力变化异常规律的认识;②该区域2022年期次重力观测前震群已发震,孕震区应力已完成部分释放,邻期差分图中重力高梯度带并不显著,未显示明显的能量累积;③观测数据累积最大重力差异性变化为60×10^(-8)m·s^(-2),时变距约70 km,该区域观测结束后于9月16日发生M_(L)3.4地震;④由于流动重力观测受点位布设密度、复测周期等限制,对于临震前重力动态变化、中小震孕震发震演变过程信息的捕捉还有待于进一步提升。Based on the mobile gravity observation data in southern Hebei Province,this study investigates the dynamic characteristics of the gravity field in the region before and after the Cixian earthquake swarm from August to September 2022.The results indicate that:(1)The significant dynamic characteristics associated with earthquake preparation and occurrence of the Cixian earthquake swarm are continuous positive changes in gravity and a zone of changing gravity gradients,which are consistent with the recognized patterns of typical preseismic gravity change anomalies.(2)Due to previous seismic activity prior to the 2022 gravity observations in this region,stress within the seismogenic zone has been partially released,resulting in an insignificant high gradient zone on adjacent period difference maps without evident energy accumulation.(3)The maximum cumulative change in observed gravity difference is 60μgal,occurring over a distance of approximately 70 km.Following these observations,small earthquakes have occurred,with M_(L)3.4 being the largest recorded on September 16th.(4)The capture of preearthquake dynamic changes in gravity and understanding the evolution process of small and medium-sized earthquakes needs further improvement due to limitations by point layout density and re-measurement periods.

关 键 词：磁县震群 重力观测 重力场 动态变化 

分 类 号：P315.72[天文地球—地震学]