2023年8月6日山东平原M_(S)5.5地震震源参数分析  

Analysis of Seismic Source Parameters of the Pingyuan,Shandong M_(S)5.5 Earthquake on August 6,2023

作　　者：李翠芹[1] 郑建常[1] 张正帅[1] 戴宗辉 LI Cuiqin;ZHENG Jianchang;ZHANG Zhengshuai;DAI Zonghui(Shandong Earthquake Agency,Jinan 250014,Shandong,China)

机构地区：[1]山东省地震局,山东济南250100

出　　处：《地震研究》2025年第2期334-340,共7页Journal of Seismological Research

基　　金：中国地震科学实验场地震可预测性国际合作项目(2018YFE0109700);中国地震局震情跟踪项目(2022010106)。

摘　　要：基于Brune模型,使用高频截止方法估计模型参数,得到2023年8月6日山东省德州市平原M_(S)5.5主震及部分M_(L)≥2.0余震的震源谱的特征参数,对不同震源参数之间的定标关系以及视应力的时空特征进行了分析讨论,结果显示:(1)主震视应力约为1.71 MPa,应力降约为3.51 MPa,矩震级为5.2,拐角频率约为0.58 Hz;(2)平原地震序列视应力与震级存在线性关系,可表示为:lg δ_(app)=0.64M_(L)+2.92;(3)余震视应力随时间发展逐渐减小,38次余震的视应力均小于0.15 MPa,低于鲁西地区小震平均视应力(0.16 MPa)。On August 6,2023,a 5.5-magnitude earthquake occurred in Pingyuan County of Dezhou City,Shandong Province.On the basis of the Brune model,we take the minimum absolute residual between the theoretical source spectrum and the observed source spectrum as the objective function,and estimate the model parameters by using the high-cut method.Then we obtain the characteristic parameters of the source spectrum of the mainshock and some aftershocks(M_(L)≥2.0).We further analyze the scaling relationship between different source parameters and the spatio-temporal characteristics of apparent stress.The conclusions are as follows:The apparent stress of the mainshock is about 1.7 MPa.The stress drop is about 3.5 MPa.Moment magnitude(M_(w))is 5.2.Corner frequency(f_(c))is about O.58 Hz;②For the Pingyuan earthquake sequence,its magnitudes have good linear relations with the corresponding apparent stress:lg δ_(app)=0.64M_(L)+2.92;The aftershocks'apparent stress gradually decreases with time.The apparent stress of the 38 aftershocks is under 0.15 MPa,lower than the average apparent stress(0.16 MPa)of the small earthquakes in western Shandong.

关 键 词：平原M_(S)5.5地震 视应力 震源参数 拐角频率 鲁西地区 

分 类 号：P315.33[天文地球—地震学]