云南地区散射衰减、吸收衰减及尾波衰减的综合研究  

Comprehensive study of scattering,intrinsic and coda attenuation in the Yunnan area

作　　者：王勤彩[1] 陈章立[1] 王中平 郑斯华[1] 

机构地区：[1]中国地震局地震预测研究所,北京100036 [2]中国台网中心,北京100045

出　　处：《地球物理学进展》2010年第2期419-431,共13页Progress in Geophysics

基　　金：国家科技支撑重点项目(2008BAC38B02;2006BAC01B02);地震行业科研专项(200708026)共同资助

摘　　要：利用云南省地震局遥测台网记录的地震波形资料,采用多流逝时间窗分析方法,得到了云南地区不同台站的散射衰减和吸收衰减,并通过单次散射模型得到了不同台站的尾波衰减.研究结果显示,云南地区的散射衰减、吸收衰减、总衰减和尾波衰减空间分布以金沙江—红河断裂带为界,均表现出西部低,东部高的特征.云南地区地震波衰减以吸收为主,2～4 Hz、4～8 Hz、8～16 Hz三个频带各台站的吸收衰减Q_i^(-1)均大于散射衰减Q_s^(-1),1～2 Hz除个别台站的吸收衰减明显小于散射衰减,其它台站均大于或接近散射衰减.尾波衰减Q_c^(-1)在1～2 Hz稍大于吸收衰减而小于总衰减,在2～4 Hz、4～8 Hz、8～16 Hz与总衰减接近,个别台站大于总衰减Q_t^(-1).云南地区散射衰减与频率的关系为Q_s^(-1)=0.0138f^(-1.61),吸收衰减与频率的关系为Q_i^(-1)=0.0119 f^(-1.86),总衰减与频率的关系为Q_t^(-1)=0.0247 f^(-1.1),尾波衰减与频率的关系为Q_c^(-1)=0.0129 f^(-0.71).与世界其它地区相比,云南地区的散射衰减处于中等偏低的水平,吸收衰减处于中等偏高的水平.The scattering and the intrinsic attenuations below stations in the Yunnan area are obtained by using the earthquake waveform data recorded through the remote digital seismic network of the Earthquake Administration of Yunnan Province,and by adopting the multiple lapse time window analysis method.The code attenuation of different stations is obtained through the single scattering model.The study result shows that,as for the spatial distribution of scattering attenuation,intrinsic attenuation,total attenuation and code attenuation,the Jinshajiang-Honghe fault serves as the border between low attenuation in the western area and high attenuation in the eastern area.The earthquake wave attenuation in the Yunnan area is mainly intrinsic,since the intrinsic attenuation Qi-1 of all stations is larger than the scattering attenuation Qs-1 on three respective frequency bands of 2～4 Hz,4～8 Hz and 8～16 Hz,while on the frequency band of 1～2 Hz,the intrinsic attenuation of individual stations is obviously smaller than the scattering attenuation but the intrinsic attenuation of most stations is larger than or equal to the scattering attenuation Qs-1.The code attenuation Qc-1,on the frequency band of 1～2 Hz,is slightly larger than the intrinsic attenuation but smaller than the total attenuation,while the code attenuation Qc-1,on the frequency band of 2～4 Hz,4～8 Hz and 8～16 Hz,is close to the total attenuation and,at individual stations,is larger than the total attenuation.The relationship between the scattering attenuation and the frequency in the Yunan area can be expressed as Qs-1=0.0138f-1.61;for the intrinsic attenuation and the frequency,it isQ1-1=0.0119f-0.86;and for the total attenuation and the frequency,it is Qt-1=0.0247f-1.1;for the code attenuation and the frequency,it is Qc-1=0.0129f-0.71.Compared with other areas worldwide,the scattering attenuation in the Yunan area is of a lower middle level and the intrinsic attenuation is of an upper middle level.

关 键 词：多流逝时间窗方法 散射衰减 吸收衰减 总衰减 尾波衰减 

分 类 号：P315[天文地球—地震学]