2009年云南姚安M_S6.0地震余震序列尾波Q_c值研究  

Study on the Coda Q_c-value for aftershock sequence of Yao'an M_S6.0 earthquake in Yunnan in 2009

作　　者：李琼[1] 秦嘉政[1] 钱晓东[1] 赵小艳[1] 毛慧玲[1] 

机构地区：[1]云南省地震局,云南昆明650224

出　　处：《地震研究》2011年第3期300-307,403,共8页Journal of Seismological Research

基　　金：云南省人民政府十项措施"云南强震活动与板缘动力学机制研究"(JCYB-20080601-4);"地球物理场和化学场动态变化与强震活动关系研究"(JCYB-20080601-5)联合资助

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。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/3 （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.

关 键 词：姚安地震 尾波衰减 余震序列 地壳Qc值 

分 类 号：P315.3[天文地球—地震学]