利用背景噪声数据提取地震台站间面波的可靠性分析——以中国大陆中东部地区的宽频带台站为例  

Reliability analysis of retrieving surface waves from ambient noise data between seismic station pairs: An example of application at broadband stations in central and eastern China

作　　者：郑现[1] 赵翠萍[1] 周连庆[1] 郑斯华[1] 

机构地区：[1]中国地震局地震预测研究所,中国北京100036

出　　处：《地震学报》2013年第2期218-228,285,共11页Acta Seismologica Sinica

基　　金：中国地震局地震预测研究所基本科研业务专项(2011TES0101);国家科技支撑项目(2008BAC38B02)资助

摘　　要：利用中国大陆中东部地区以国家台网为主的100个分布均匀的宽频带地震台记录到的21个月的连续波形数据,经过单台数据处理和互相关叠加计算后,由时频分析法提取了研究区各台站对间瑞雷波的格林函数.为了检验经验格林函数的可靠性和稳定性,对沿部分路径的经验格林函数和频散曲线进行了质量评估.检测结果表明,自21个月叠加的台站对间背景噪声中提取的经验格林函数与实际的地震面波一致,提取的格林函数可靠.此外,统计了使用从3—21个月不同长度数据叠加后,经验格林函数信噪比大于10的频散曲线数目.结果表明,至少要使用12个月的数据才能提取到信噪比足够大,数目足够多,可用于反演面波速度结构的经验格林函数;12个月的叠加时长,可以保证30s以下周期的频散曲线在时间上稳定.We retrieved Rayleigh wave Green functions between all possible station pairs after pre-processing, cross-correlation and stacking the data, which are 21 months＇ continuous ambient seismic noise recorded by 100 evenly distrib- uted broadband seismic stations mainly in the National Seismic Network in central and eastern Chinese mainland. The quality of the empirical Green func- tions （EGFs） and the dispersion curves along selected paths were estimated to measure the reliability and stability of the EGFs. Our results display that the EGFs are correlated with the earthquake signals, suggesting the reliability of the EGFs. In addition, we counted the number of dispersion measurements with SNR^10 retrieved from the time-series of different lengths （3--21 months）. The result shows that, to obtain enough reliable EGFs for velocity tomography, at least 12 months＇ data should be used and 12 months＇ data can make sure that dispersion curves under 30 s are temporally stable.

关 键 词：背景噪声 经验格林函数 频散曲线 中国大陆中东部地区 

分 类 号：P315.31[天文地球—地震学]