接收函数反演地壳S波速度结构的有效约束方法  

An effective technique to constrain the non-uniqueness of receiver function inversion

作　　者：彭恒初[1] 胡家富[1] 杨海燕[1] 文丽敏[1] 

机构地区：[1]云南大学地球物理系,昆明650091

出　　处：《地球物理学报》2012年第4期1168-1178,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(U0933602);云南省基金资助项目(2007D013M)资助

摘　　要：本文通过对径向接收函数和垂直向接收函数进行低通滤波,获取了S波视速度随低通滤波参数的变化曲线,然后利用经验关系将它转换成了台站下方的S波速度结构,并以此作为接收函数反演的初始模型.理论数值实验表明:由于初始模型的S波速度值提供了有效的约束,即使Moho面深度并不准确,但反演迭代过程还是快速地向真解逼近.另外,通过给观测波形加入10%的噪声,在保持S波速度不变的情况下,分别对波速比进行5%的正负扰动(即泊松比分别扰动为0.23和0.27),反演结果仍然快速向真解收敛.对保山台记录的远震接收函数反演结果表明:用本文方法反演所得结果与测深结果较为一致.这充分说明只要S波速度值(而非泊松比)能够提供有效的约束,接收函数的反演过程对P波速度的选取并不敏感.The relation curve between the apparent velocity of S wave and the filter-parameter is obtained by low-pass filtering the radial and vertical receiver function,then it is transformed into the S velocity structure beneath the station with empirical formula;moreover,the S velocity structure will be regarded as initial model for receiver function inversion.The numerical simulation indicated that the inversion processes would approach quickly to the true model once the initial S velocity can supply the effective constraint to inversion,even if the depth of Moho is not accurate.In addition,for the same initial S structure,the inversion results also approach to the true model quickly,even adding 10% of random noises to the ＂observed＂ receiver function,and 5% of positive and negative perturbation to the velocity ratio（corresponding to the Poisson′s ratio of 0.27 and 0.23） respectively.We processed the teleseismic receiver function recorded by Baoshan station.The result from our method is similar to that of sounding section.These confirmed that the inversion processes of receiver function are not sensitive to the initial P velocity if the initial S wave velocity can provide the effective constraint information.

关 键 词：接收函数 反演 初始模型 

分 类 号：P315[天文地球—地震学]