title: Depth variations of P-wave azimuthal anisotropy beneath Mainland China.
abstract: A high-resolution model of P-wave anisotropic tomography beneath Mainland China and surrounding regions is determined using a large number of arrival-time data recorded by the China seismic network, the International Seismological Centre (ISC) and temporary seismic arrays deployed on the Tibetan Plateau. Our results provide important new insights into the subducted Indian plate and mantle dynamics in East Asia. Our tomographic images show that the northern limit of the subducting Indian plate has reached the Jinsha River suture in eastern Tibet. A striking variation of P-wave azimuthal anisotropy is revealed in the Indian lithosphere: the fast velocity direction (FVD) is NE-SW beneath the Indian continent, whereas the FVD is arc parallel beneath the Himalaya and Tibetan Plateau, which may reflect re-orientation of minerals due to lithospheric extension, in response to the India-Eurasia collision. There are multiple anisotropic layers with variable FVDs in some parts of the Tibetan Plateau, which may be the cause of the dominant null splitting measurements in these regions. A circular pattern of FVDs is revealed around the Philippine Sea slab beneath SE China, which reflects asthenospheric strain caused by toroidal mantle flow around the edge of the subducting slab.
authors.affiliation: Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China.|Department of Geophysics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Department of Geophysics, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Xu
authors.affiliation: Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China.
authors.forename: Bengang
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yaolin
authors.initials: Y
authors.lastname: Shi