Eastward subduction of the Indian plate beneath the Indo-Myanmese arc revealed by teleseismic P-wave tomography

作     者：Yu Gao Jiansi Yang Yu Zheng Yu Gao;Jiansi Yang;Yu Zheng

作者机构：Institute of GeophysicsChina Earthquake AdministrationBeijing 100081China 

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

年 卷 期：2022年第35卷第4期

页      面：243-262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：This work is jointly supported by the Youth Program of National Natural Science Foundation of China(Nos.41874075 and 41904057) 

主　　题：teleseismic tomography plate gap Indo-Myanmese arc Tengchong volcano 90°E Ridge 

摘      要：The deep structure of the eastward-subducting Indian plate can provide new information on the dynamics of the India-Eurasia *** collected and processed waveform data from temporary seismic arrays(networks)on the eastern Tibetan Plateau,seismic arrays in Northeast India and Myanmar,and permanent stations of the China Digital Seismic Network in Tibet,Gansu,Qinghai,Yunnan,and *** combined these data with phase reports from observation stations of the International Seismological Center on the Indian plate and selected 124,808 high-quality P-wave relative travel-time ***,we used these data to invert the 3-D P-wave velocity structure of the upper mantle to a depth of 800 km beneath the eastern segment of the arcuate Himalayan orogen,at the southeastern margin of the Tibetan *** results reveal a high-angle,easterly dipping subducting plate extending more than 200 km beneath the Indo-Myanmese *** plate breaks off at roughly 96°E;its fragments have passed through the 410-km discontinuity(D410)into the mantle transition zone(MTZ).The MTZ beneath the Tengchong volcanic area contains a high-velocity anomaly,which does not exceed the Red River fault to the *** other large-scale continuous subducted plates were observed in the ***,a horizontally spreading high-velocity anomaly was identified on the D410 in some *** anomaly may represent the negatively buoyant 90°E Ridge plate or a thickened and delaminated lithospheric block experiencing collision and compression at the southeastern margin of the Tibetan *** Tengchong volcano may originate from the mantle upwelling through the slab window formed by the break-off of the subducting Indian continental plate and oceanic plate in the upper ***-velocity upper mantle materials on the west side of the Indo-Myanmese arc may have supplemented materials to the Tengchong volcano.