Crust azimuthal anisotropy beneath the eastern Tibetan Plateau revealed by ambient noise tomography

Xue-Wei Bao, & Xiaodong Song

Submitted August 9, 2017, SCEC Contribution #7449, 2017 SCEC Annual Meeting Poster #030

The continental collision between India and Eurasia in the Cenozoic has resulted in the rise and growth of the vast Tibetan Plateau (TP). Various geodynamic models, such as rigid-block extrusion, continuous deformation, and the mid-lower crustal flow, have been proposed to describe the growth and expansion of eastern Tibet. To better understand the deformation mechanism of the eastern TP, we performed ambient noise tomography using data from permanent and temporary stations and constructed Rayleigh wave azimuthally anisotropic phase-velocity maps at periods from 8 to 30 s, which mainly sample the crustal structure. The dominant direction of fast wave propagation is oriented NW-SE in the northeastern and eastern TP and N-S in the southeastern TP, which is consistent with the trends of main strike-slip faults and the fast polarization directions of SKS waves and suggests vertically coherent deformation. Furthermore, the strength of anisotropy is continuous across main strike-slip faults, which contracts with the prediction of rigid-block extrusion model. Taken together, our model supports distributed coherent deformation in the eastern TP.

Key Words
ambient noise tomography, Tibet, lithospheric deformation

Citation
Bao, X., & Song, X. (2017, 08). Crust azimuthal anisotropy beneath the eastern Tibetan Plateau revealed by ambient noise tomography. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Seismology