Crustal and uppermost mantle structure of the northeastern Qinghai-Xizang Plateau from joint inversion of surface wave dispersions and receiver functions with P velocity constraints

作     者：Pei Zhang Xiaodong Song Jiangtao Li Xingchen Wang Xuezhen Zhang Pei Zhang;Xiaodong Song;Jiangtao Li;Xingchen Wang;Xuezhen Zhang

作者机构：Institute of GeophysicsChina Earthquake AdministrationBeijing 100081China The Second Monitoring and Application CenterChina Earthquake AdministrationXi'an 710054China Institute of Theoretical and Applied GeophysicsSchool of Earth and Space SciencesPeking UniversityBeijing 100871China Department of GeophysicsSchool of Geodesy and GeomaticsWuhan UniversityWuhan 430079China 

出 版 物：《Earthquake Science》 (地震学报（英文版）)

年 卷 期：2024年第37卷第2期

页      面：93-106页

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：supported by the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0306) the Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB21B32) the National Natural Science Foundation of China(No.42174069) 

主　　题：joint inversion receiver functions surface waves crustal thickness vP/vS ratio NE Qinghai-Xizang Plateau 

摘      要：Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower *** or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.