【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.更多还原

【Abstract】 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 the multiple scattering effect of the medium.更多还原