联合反演面波频散和H/V获取地壳上地幔的横波速度及径向各向异性研究  

Study on the joint inversion of surface wave dispersion curves and H/V to obtain shear velocity and radial anisotropy of crust and uppermost mantle

作　　者：胥鸿睿 程天健[1] 漆乔木 付锦昌 李川 XU HongRui;CHENG TianJian;QI QiaoMu;FU JinChang;LI Chuan(Southwest Jiaotong University,Faculty of Geosciences and Engineering,Chengdu 611756,China;Chengdu University of Technology,College of Geophysics,Chengdu 610059,China;China Water Pearl River Planning,Survey and Design Co.,Ltd.,Guangzhou 510635,China;Kunming University,School of Mathematics,Kunming 650214,China)

机构地区：[1]西南交通大学地球科学与工程学院,成都611756 [2]成都理工大学地球物理学院,成都610059 [3]中水珠江规划勘测设计有限公司,广州510635 [4]昆明学院数学学院,昆明650214

出　　处：《地球物理学进展》2024年第5期1800-1809,共10页Progress in Geophysics

基　　金：国家自然科学基金(41804139,41904059);四川省自然科学基金(23NSFSC3001);河北省自然科学基金(D2022403044);中央高校基本科研项目(2682023CX015,2682023CX011);中国博士后科学基金第73批面上项目(2023M732912)联合资助。

摘　　要：横波速度的径向各向异性反映了物质的变形和主导应力的方向.目前,勒夫面波和瑞雷面波的相、群速度频散特征已经被广泛用于确定地壳上地幔的横波速度及径向各向异性.但仅反演相对长周期(譬如,>5 s)的面波频散难以约束地壳浅部尤其是沉积层的横波速度及径向各向异性.此外,面波频散反演中不准确的浅部结构亦会导致更深部的反演结果的偏差.相较于面波频散,相同周期的瑞雷面波质点运动的水平-垂直振幅比(H/V)对横波速度的敏感深度明显更浅.在面波相、群速度与H/V具有相似的空间分辨率的前提下,本文提出联合反演勒夫面波和瑞雷面波频散与H/V获取地壳上地幔的横波速度及径向各向异性的方法.基于渤海湾盆地西缘的实际案例和理论模型测试的结果表明,引入H/V进行联合反演可以显著改善地壳尤其是沉积层的横波速度及径向各向异性的反演结果.本文所提出方法有助于地壳变形和相关构造应力状态的深入研究.The radial anisotropy reflects the deformation of materials and the direction of principle stress.Currently,the dispersive characteristics of Love-wave and Rayleigh-wave phase and group velocities have been widely used to determine the shear velocity and radial anisotropy of crust and uppermost mantle.However,the shear velocity and radial anisotropy of the shallow crust especially the sediments are poorly constrained in the dispersion inversion within relatively long periods(e.g.,>5 s).Furthermore,the inverted results at deeper depths can be biased due to inaccurate shear velocity and radial anisotropy at shallow depths in dispersion inversion.Compared to surface wave dispersion,the Rayleigh-wave Horizontal-to-Vertical(H/V)ratios of particle motion are particularly sensitive to shallower shear velocity.Based on the similar spatial resolution of surface-wave phase and group velocities and H/V,we propose a method for constructing Vs profiles and radial anisotropy based on the joint inversion of the Love-wave and Rayleigh-wave dispersion curves and H/V.According to the practical case of the western Bohai Bay Basin and synthetic test,the accuracy of the shear velocity and radial anisotropy of crust,especially the sediments,is considerably improved by the joint inversion including H/V.The proposed method is beneficial to further study on the state of crustal deformation and associated tectonic stress.

关 键 词：面波频散 H/V 联合反演 横波速度 径向各向异性 地壳上地幔 

分 类 号：P315[天文地球—地震学]