品质因子的尾波测定方法讨论  

Discussion on Coda Wave Measurement Methods for Quality Factor

作　　者：刘希强[1] 石玉燕[1] 曲均浩[1] 周彦文[1] 李红[1] 李铂[1] 张坤[1] 

机构地区：[1]山东省地震局,济南市历下区文化东路20号250014

出　　处：《中国地震》2009年第1期11-23,共13页Earthquake Research in China

基　　金：山东省自然科学基金(Y2007E09);地震科学联合基金(C08028);山东数字地震波资料应用研究专项经费共同资助

摘　　要：品质因子是定量刻画地震波传播过程中能量衰减情况的特征参数。理论上可根据观测台站记录的具有相同射线路径的地震波尾波品质因子的时间动态变化特征来探讨其与地震孕育过程间的关系,但实际上由不同地震的尾波测量得到的品质因子对应于不同的地震波射线路径,品质因子的时间变化除了与区域应力场的变化因素有关以外,还与区域介质的横向和纵向非弹性程度和散射波波阵面围成的椭球体的范围有关。本文根据前人研究结果并结合具体实例讨论了品质因子与地震震源距及不同流逝时间的关系;讨论了品质因子与频率变化的关系;提出了对不同地震采用不同流逝时间的尾波测定品质因子的方法。改进后的品质因子测量方法可有效去除由于不同地震或同一地震的地震散射波在纵向介质中穿透深度的不同而导致的对品质因子测量结果的影响,从而有利于捕捉到品质因子的异常变化特征与地震孕育过程的关系。Quality factor is a parameter which describes the energy attenuation about seismic wave. In theory, we can obtain the relation between change characteristics with time about quality factor of coda wave and the strong earthquake preparation process on the basis of quality factor of coda wave with the same ray path. But quality factors of coda wave in different measurements correspond to different seismic wave ray paths in reality, the changes of quality factor with time is related to non-elasticity characteristics of medium and the volume of scattering ellipsoid formed by scattered wave phase front besides the changes of region stress field. This paper discusses the relation among quality factor, epicenter distance and different lapse time, and also the relation between quality factor and frequency. Furthermore the determination method of coda wave quality factor is put forward. The improved determination method of quality factor which removes the influence by different earthquake or propagation depth difference of scattered wave may improve the measurement precision so that we can get the abnormal change information of quality factor and the relation between quality factor and earthquake preparation procession.

关 键 词：品质因子 尾波 测量方法 讨论 应用 

分 类 号：P315[天文地球—地震学]