2009年云南姚安M_S6.0地震余震序列尾波Q_c值研究
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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 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.
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.
引文
陈学庭.1992.澜沧和耿马大地震Q值随时间的变化[M]//中国地球物理学会年刊.北京:地震出版社.
高龙生,华正兴,李瑞瑄.1987.用尾波的强度和衰减估算北京地区S波的平均自由程[J].地震学报,9(4):347-363.
胡鸿翔,陆函行,王椿镛,等.1986.滇西地区地壳结构的爆破地震研究[J].地球物理学报,29(2):133-144.
阚荣举,张四昌,晏凤桐,等.1977.我国西南地区现代构造应力场与现代构造活动特征的探讨[J].地球物理学报,20(2):96-109.
李白基,秦嘉政,钱晓东,等.2004.云南姚安地区的尾波衰减[J].地震学报,26(1):47-52.
李白基,秦嘉政,谢庆茵,等.2000.云南武定1995年地震余震尾波Qc值[J].地震地磁观测与研究,21(2):1-6.
李琼,秦嘉政,钱晓东.2007.2007年宁洱6.4级地震余震序列尾波Qc值研究[J].地震研究,30(4):337-343.
钱晓东,李白基,秦嘉政.2004.2001年云南施甸MS5.9地震余震序列尾波Qc值研究[J].地震地磁观测与研究,25(1):9-17.
钱晓东,秦嘉政,李白基.2006.澜沧江流域水电工程地区的尾波衰减[J].地震研究,29(3):215-220.
秦嘉政,刘祖荫,龙晓帆.1995.滇西实验场两次中强地震前后尾波衰减的区域特征分析[J].中国地震,11(3):212-221.
秦嘉政.1989.云南地区短周期波区域Q值与地震烈度衰减[C]//云贵地区地震危险性研究文集.昆明:云南科技出版社,253-260.
秦嘉政.1992.澜沧—耿马地震后尾波衰减的区域特征[J].地震学报,14(1):71-82.
王伟君,刘杰.2006.云南4个地震序列Q c-1值变化特征对比研究[J].地震,26(1):19-25.
Aki K.1969.Analysis of the seismic coda of local earthquakes as scattered waves[J].J Geophys Res,74(2):615-631.
Chouet B.1979.Temporal variation in the attenuation of earthquake codanear Stone Canyon,California[J].Geophys Res Lett,6(3):143-146.
Hartzell S,Leeds A,Franbel A,et al.1996.Site response for urban LosAngeles using aftershocks of the Northridge earthquake[J].BSSA,86(1B):S168-S192.
Herrmann R B.1980.Q estimates using the coda of local earthquakes[J].BSSA,70(2):447-468.
Jin A,Aki K.1986.Temporal changein Q before the Tangshan earth-quakeof1976and the Haicheng earthquakeof1975[J].J GeophysRes,91(B1):665-673.
Jin A,Aki K.1989.Spatial and temporal correlation between coda Q andseismicity and itsphysical mechanism[J].J Geophys Res,94(B10):14041-14059.
Sing S,Herrmann R B.1983.Regionalization of crustal coda Q in the con-tinental United states[J].J Geophys Res,88(B1):527-538.
Woodgold C R D.1990.Estimation of Q in eastern Canada using codawaves[J].BSSA,80(2):411-429.
高龙生,华正兴,李瑞瑄.1987.用尾波的强度和衰减估算北京地区S波的平均自由程[J].地震学报,9(4):347-363.
胡鸿翔,陆函行,王椿镛,等.1986.滇西地区地壳结构的爆破地震研究[J].地球物理学报,29(2):133-144.
阚荣举,张四昌,晏凤桐,等.1977.我国西南地区现代构造应力场与现代构造活动特征的探讨[J].地球物理学报,20(2):96-109.
李白基,秦嘉政,钱晓东,等.2004.云南姚安地区的尾波衰减[J].地震学报,26(1):47-52.
李白基,秦嘉政,谢庆茵,等.2000.云南武定1995年地震余震尾波Qc值[J].地震地磁观测与研究,21(2):1-6.
李琼,秦嘉政,钱晓东.2007.2007年宁洱6.4级地震余震序列尾波Qc值研究[J].地震研究,30(4):337-343.
钱晓东,李白基,秦嘉政.2004.2001年云南施甸MS5.9地震余震序列尾波Qc值研究[J].地震地磁观测与研究,25(1):9-17.
钱晓东,秦嘉政,李白基.2006.澜沧江流域水电工程地区的尾波衰减[J].地震研究,29(3):215-220.
秦嘉政,刘祖荫,龙晓帆.1995.滇西实验场两次中强地震前后尾波衰减的区域特征分析[J].中国地震,11(3):212-221.
秦嘉政.1989.云南地区短周期波区域Q值与地震烈度衰减[C]//云贵地区地震危险性研究文集.昆明:云南科技出版社,253-260.
秦嘉政.1992.澜沧—耿马地震后尾波衰减的区域特征[J].地震学报,14(1):71-82.
王伟君,刘杰.2006.云南4个地震序列Q c-1值变化特征对比研究[J].地震,26(1):19-25.
Aki K.1969.Analysis of the seismic coda of local earthquakes as scattered waves[J].J Geophys Res,74(2):615-631.
Chouet B.1979.Temporal variation in the attenuation of earthquake codanear Stone Canyon,California[J].Geophys Res Lett,6(3):143-146.
Hartzell S,Leeds A,Franbel A,et al.1996.Site response for urban LosAngeles using aftershocks of the Northridge earthquake[J].BSSA,86(1B):S168-S192.
Herrmann R B.1980.Q estimates using the coda of local earthquakes[J].BSSA,70(2):447-468.
Jin A,Aki K.1986.Temporal changein Q before the Tangshan earth-quakeof1976and the Haicheng earthquakeof1975[J].J GeophysRes,91(B1):665-673.
Jin A,Aki K.1989.Spatial and temporal correlation between coda Q andseismicity and itsphysical mechanism[J].J Geophys Res,94(B10):14041-14059.
Sing S,Herrmann R B.1983.Regionalization of crustal coda Q in the con-tinental United states[J].J Geophys Res,88(B1):527-538.
Woodgold C R D.1990.Estimation of Q in eastern Canada using codawaves[J].BSSA,80(2):411-429.
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