【摘要】 利用云南大姚地震台记录到的2009年姚安6.0级地震余震序列的数字化波形观测资料,基于尾波单次散射理论,估算该次地震震源区尾波Qc值。结果表明:中心频率为1.5 Hz时,振幅衰减率β(f)在-0.141 27～-0.043 05之间,平均值为-0.074 60;Qc值在33.3～99.8之间,平均值为65.5。并得出Qc值与频率的关系:尾波波源因子与震级成正比,与频率成反比。主震发生后头几天,尾波Qc值(1.5 Hz)波动较大,之后在±1.5倍方差线内趋于稳定,且没有超过5级的强余震发生。姚安地区尾波Qc值具有构造运动活跃、地震活动频繁地区的低Qc值特征。更多还原

【Abstract】 The coda-wave attenuation factor Qc at the source region of Yao’an,Yunnan,MS6.0 earthquake in 2009 is estimated through single-scattering theory of coda wave on the basis of the digital waveform data of aftershock sequence recorded by Da’yao Station.When central frequency f=1.5 Hz,the coda attenuation ratio β(f) in Yao’an region ranges from-0.141 27 to-0.043 05,and the average is-0.074 60.The Qc-value of coda ranges from 33.3 to 99.8,and the average is 65.5.The relation between the Qc-value and frequency f is Qc(f)=45.3 f0.97.The coda factor is in direct proportion to magnitude,and in inverse proportion to frequency.In the first few days after the main shock,the Qc-value(1.5 Hz) of coda fluctuated obviously,it showed a tendency toward stabilization within the line of ±1.5 times of variance,and the strong aftershocks smaller than M5 will occur.The Yao’an region has the characteristics of active tectonic-movement,frequent seismic-activity,and low Qc-value.更多还原