东北地区背景噪声的Rayleigh和Love波相速度层析成像  

Phase velocity tomography of Rayleigh and Love waves using ambient noise in Northeast China

作　　者：付媛媛[1] 高原[1] 

机构地区：[1]中国地震局地震预测研究所(地震预测重点实验室),北京100036

出　　处：《地球物理学报》2016年第2期494-503,共10页Chinese Journal of Geophysics

基　　金：中国地震局中日韩国际合作专项(ZRH2013-03;ZRH2014-05);中国地震局地震预测研究所基本科研业务费专项(2015IES0304)资助

摘　　要：本文利用中国数字地震台网位于东北地区的122个宽频地震台站的18个月记录的三分量连续地震噪声数据,采用互相关方法提取了Rayleigh和Love波经验格林函数,并利用时频自动分析技术获取了相应的相速度频散曲线.通过反演频散曲线,获得了Rayleigh和Love波周期为8-35s的二维相速度分布.结果表明,东北地区相速度的分布存在横向和垂向的不均匀性.短周期的相速度分布同地表地质构造密切相关,松辽盆地及山间沉积盆地呈现低速异常,而大兴安岭、小兴安岭及东部的一些山岭显示高速异常.随着周期的增加,位于中间的松辽盆地变为高低速相间,两侧的造山带呈现低速异常.这种异常的转变,可能是受构造活动或者莫霍面深度的影响.另外,在周期为20-35s频段内,Rayleigh和Love波同一周期的相速度在松辽盆地和位于吉林地区的郯庐断裂带表现不一致,表明可能存在径向各向异性.We obtain the 2Dphase velocity of Rayleigh and Love waves of the periods 8sto 35 s in the Northeast China using ambient seismic noise recorded at 122broad-band stations of Chinese Digital Seismic Network.All available three-component time series for the 18 month have been cross-correlated to yield estimates of empirical Rayleigh and Love wave Green′s functions.Phase velocity dispersion curves for both Rayleigh and Love waves are measured for each interstation path by applying frequency-time analysis.The Rayleigh and Love wave phase speed maps at short periods（8~12s）show clear correlations with major geological structures.The Songliao Basin has obvious low velocity,while the mountains（Da Hinggan Ling,Xiao Hinggan Ling,Zhangguangcai Ling）have high velocity.However,with the increasing period,the Songliao Basin gradually changes to high velocity,and the mountains on its two sides show low velocity.This may be related to the deep tectonic events or the Moho depth.Rayleigh and Love wave phase velocitymaps at the same period exhibit different features in the Songliao Basin and Tanlu fault in the Jilin area from the periods 20 sto 35s.This difference may imply the existence of radial anisotropy.

关 键 词：RAYLEIGH波 LOVE波 背景噪声层析成像 中国东北 

分 类 号：P315[天文地球—地震学]