Crustal structure beneath SE Tibet from joint analysis of receiver functions and Rayleigh wave dispersion

New constraints on the pattern of crustal flow in SE Tibet are obtained from joint analysis of receiver functions and Rayleigh wave dispersion with a newly deployed seismic array. The crust in the Sichuan-Yunnan Diamond Block has an average thickness of ~45 km and gradually thins toward the Indo-China Block to the west and the Yangtze Block to the east. High V_P/V_S ratios are detected to the west of the Xiaojiang fault, but not in the Yangtze Block to the east. The S wave velocity profile reveals that intra-crustal low-velocity zones (IC-LVZs) are strongly heterogeneous, with two LVZs in the middle and mid-lower crust, respectively, in marked contrast to previous observations of a single LVZ. Combined with other observations, the two IC-LVZs are interpreted as isolated channels of crustal flow at different depths beneath SE Tibet, resulting in the observed complex pattern of radial anisotropy and further elucidating patterns of flow and deformation. Key Points Joint inversion shows two major low-velocity zones (LVZs) at different depths Two major LVZs suggest isolated channels of crustal flow beneath SE Tibet Results indicate previously unknown patterns of flow and deformation