龙滩水库地区P波、S波和尾波衰减  

Attenuation of P,S and coda waves in Longtan reservoir region

作　　者：华卫[1] 赵翠萍[1] 陈章立[1] 郑斯华[1] 

机构地区：[1]中国地震局地震预测研究所,中国北京100036

出　　处：《地震学报》2009年第6期620-628,共9页Acta Seismologica Sinica

基　　金：国家科技支撑项目(2006BAC01B04-02-01);国家科技支撑项目(2008BAC38B02-3);地震科学联合基金项目(606042)共同资助

摘　　要：利用发生在龙滩水库地区的144次ML≥1.0地震资料,研究了该地区地壳介质的衰减特征,并采用尾波归一化方法分别估算了P波、S波的品质因子QP和QS,用单次反散射模型计算了尾波品质因子Qc.结果表明,该地区上述3个值与频率的依赖关系分别为QP(f)=(7.43±0.78)f(1.05±0.06),QS(f)=(13.08±3.20)f(1.76±0.15),Qc(f)=(50.52±2.71)f(1.13±0.03),总体呈现低Q0和高η值的特点.在所研究的频带范围1—16Hz内,QS/QP比值均大于1,表明该地区体波衰减中散射可能起着较大作用.Qc与QS的比较结果表明,在小于8Hz时,QS<Qc;而大于8Hz时,则QS>Qc.这可能是由于介质的多次散射作用的结果.Seismic attenuation properties of the crust medium in Longtan,Guangxi,reservoir region have been investigated using digital seismogram data of 144 ML≥1.0 earthquakes occurred in the region.The extended coda-normalization method has been used to calculate the quality factors for P wave （QP） and S waves （QS）,and the single back-scattering model was used to determine the quality factors for coda wave （Qc）.The results show that the frequency dependent relationships of these three quality factors in the region are QP（f）=（7.43±0.78）f（1.05±0.06）, QS（f）=（13.08±3.20）f（1.76±0.15） and Qc（f）=（50.52±2.71）f（1.13±0.03）,respectively,indicating a property of low Q0 and high η.The ratio QS/QP is found to be greater than one for the frequency range （1--16 Hz） considered here,indicating scattering being an important factor of body wave attenuation in the region.A comparison between Qc and QS shows that QS〈Qc for frequencies below 8 Hz and QS〉Qc for frequencies above 8 Hz.This may be attributed to th...更多e multiple scattering effect of the medium.

关 键 词：地震波衰减 尾波归一化 龙滩水库 

分 类 号：P315.31[天文地球—地震学]