Velocity structure and radial anisotropy beneath the northeastern Tibetan Plateau revealed by eikonal equation-based teleseismic P-wave traveltime tomography

作     者：Mengyang LI Shaolin LIU Dinghui YANG Xiwei XU Wenhao SHEN Chaodi XIE Wenshuai WANG Shuxin YANG Mengyang LI;Shaolin LIU;Dinghui YANG;Xiwei XU;Wenhao SHEN;Chaodi XIE;Wenshuai WANG;Shuxin YANG

作者机构：National Institute of Natural HazardsMinistry of Emergency Management of ChinaBeijing 100085China School of Earth SciencesYunnan UniversityKunming 650091China Department of Mathematical SciencesTsinghua UniversityBeijing 100084China School of Mathematics and StatisticsNingxia UniversityYinchuan 750021China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2022年第65卷第5期

页      面：824-844页

核心收录：

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 National Institute of Natural Hazards, Ministry of Emergency Management of China (Grant No. ZDJ2019-18) supported by the National Natural Science Foundation of China (Grant No. U1839206) supported by the Open Fund Project of the State Key Laboratory of Lithospheric Evolution (Grant No. SKL-K202101) the National Natural Science Foundation of China (Grant Nos. 42174111 and 42064004) Institute of Geophysics, China Earthquake Administration (Grant Nos. DQJB16A03, DQJB17A01) 

主　　题：Northeastern Tibetan Plateau Tomography P-wave velocity Radial anisotropy structure Indian plate 

摘      要：The northeastern Tibetan Plateau serves as the frontier for the northeastward expansion of the *** this area,the Tibetan Plateau interacts with the surrounding blocks,such as the Alxa Block,the Ordos Block,the Kunlun-West Qinling belt and the Sichuan *** of this expansion and interaction,this area suffers from intense *** present,the evolution and deformation mechanisms of the northeastern Tibetan Plateau remain *** provide new insights into these mechanisms,in this study,we conduct tomography of the P-wave velocity and radial anisotropy structures beneath the northeastern Tibetan *** choose a total of 667 teleseismic earthquakes from August 2006 to October *** of these earthquakes were recorded by 921 broadband seismic stations in the northeastern Tibetan Plateau and surrounding *** first perform cross-correlation on waveforms of each station pair and obtain 770,749 P-wave traveltime ***,we invert the differential traveltime data by applying eikonal equation-based teleseismic ***,the P-wave velocity and radial anisotropy structures at depths from 30 to 800 km below the northeastern Tibetan Plateau are *** tomographic model shows clear low-velocity anomalies and positive radial anisotropy in the lower crust under the northeastern Qilian orogen,the northeastern Songpan-Ganzi belt and the western Qinling fold *** features are integrated to demonstrate the existence of lower crustal flow in the study *** low-velocity anomalies and positive radial anisotropy are found in the uppermost mantle beneath the Qilian orogen,the northeastern Songpan-Ganzi belt and western Qinling fold *** characteristics are combined to infer a weak lithosphere and horizontal asthenospheric flow under these tectonic *** the Ordos Block and the Sichuan Basin exhibit clear high-velocity anomalies and negative radial anisotropy in the uppermost mantle,thereby reflect