【摘要】 利用震源距23 km范围内观测的2000年姚安MS6.5地震余震记录,计算了震源及近邻区域的尾波规一直达S波在频率1.5~20 Hz之间的傅里叶谱振幅.结果显示谱振幅随震源距增大而增大,在对谱振幅进行了震源辐射方向性校正之后,才出现谱振幅随震源距衰减的现象.由此获得了震源及近邻区域S波的Q(f)值,可表示为QS(f)=8.9f0.98.其值比由尾波得出的姚安地区的平均QC(f)值低得多,表明了震源破裂带的强烈非均匀性对QS(f)的重大影响.更多还原

【Abstract】 The Fourier coda normalized spectral amplitudes in the frequency range of 1.5 to 20Hz of the direct S waves were calculated using the aftershock recordings observed within hypocentral distance 23 km in the source and adjacent area of the 2000 Yao’an M-S6.5 earthquake.The spectral amplitude strengthens with the increase of hypocentral distance,rather than weakens.After correction for the effect of source radiation directivity on the spectral amplitudes,the phenomenon of attenuation with increasing hypocentral distance appears then.The Q（f） of the shear waves in the source and adjacent area is obtained therefrom.It is expressed as Q-S（f）=8.9f^0.98.Its value is significantly lower than Q-C（f） for the Yao’an region calculated from the 30-second-elapse-time S-wave coda.It shows the serious effect of strong heterogeneity of the earthquake rupture zone on Q-S（f）.更多还原