基于频谱分析的矩震级测定方法——以山西地震带为例  

Determination of Moment Magnitude Based on Spectrum Analysis——Taking Shanxi Seismic Belt as an Example

作　　者：李斌[1,2] 靳一丹[1] 李嘉丽 王振东 Nganaye Gomer De Dieu LI Bin;JIN Yi-dan;LI Jia-li;WANG Zhen-dong;Nganaye Gomer De Dieu(Department of Earth Science and Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Institute of Prevention for Earthquake and Geological Hazards,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学地球科学与工程系,山西太原030024 [2]太原理工大学地震与地质灾害防治研究所,山西太原030024

出　　处：《山西地震》2023年第1期1-8,共8页Earthquake Research in Shanxi

基　　金：山西省自然科学基金资助项目(201901D111051)。

摘　　要：矩震级M_(W)是目前量度地震大小最理想的物理量,已成为国际地震学界开展研究的首选震级。对于中强地震事件,矩震级M_(W)通常可以利用长周期地震波,基于矩张量反演计算获得;对于约3级以下的地震事件,直接进行矩张量反演有时会产生较大误差。本文以山西地震带为例,利用山西地震台网数字波形资料,开展研究区Q值函数模型的分析评估与基于频谱分析的矩震级测定。研究结果表明,基于Q值函数Q(f)=299.4f^(0.563)计算的频谱M_(W)更接近矩张量反演的M_(W),与Q值模型参数Q_(0)、α和κ的优化组合结果存在较好吻合;对于3.6≤M_(L)≤5.1地震事件,基于频谱分析计算得到的矩震级与基于矩张量反演矩震级较接近。在已具有详细的区域非弹性衰减模型基础上,基于频谱分析快速测定中小地震的矩震级具有可行性。Moment magnitude M_W is the most ideal physical quantity for measuring earthquake size at present,and has become the preferred magnitude selected by the international seismological community.For moderate-strong earthquake events,the moment magnitude M_W can usually be obtained by using long-period seismic waves based on moment tensor inversion calculation.However,for earthquake events with magnitude below about 3,direct moment tensor inversion sometimes produces large errors.In this paper,taking Shanxi seismic belt as an example,using the digital waveform data of the seismic network of Shanxi province,the analysis and evaluation of the Q-value function model in the study area and the moment magnitude measurement based on spectrum analysis are carried out.The research results show that the spectrum M_W calculated based on the Q-value function Q(f)=299.4f^(0.563) is closer to the M_W of the moment tensor inversion,and there is a good agreement with the optimal combination results of the Q-value model parameters Q0,α and κ.For events with 2.4≤M_L≤5.1,the moment magnitude calculated based on spectrum analysis is close to the moment magnitude based on moment tensor inversion.On the basis of the detailed research results of the regional inelastic attenuation model,it is feasible to quickly determine the moment magnitude of small and medium earthquake based on spectrum analysis.

关 键 词：矩震级 频谱分析 中小地震 山西地震带 

分 类 号：P315.32[天文地球—地震学]