Study of China lithosphere by receiver function and surface wave tomography
Final Report Abstract
We used P and S receiver function methods and multi-mode surface wave tomography to study the lithospheric structure of China. We modeled waveforms of 50338 vertical component multimode Rayleigh wave seismograms, recorded at 144 permanent and more than 300 temporary broadband stations in and around China and derived a 3-D upper mantle shear wave velocities. The seismic lithosphere reaches a thickness of 200 km beneath the Pamir-Tibetan plateaus. Also observed as relatively thick seismic lithosphere (>100km) are the Indian plate, Sichuan basin, Ordos block and Tarim basin. The lithosphere in the eastern part of the Yangtze craton is as thin as 70-80 km, whereas it is too thin in the North China craton to be resolved. Beneath these two cratons we found evidence for an extensive high velocity body at depths of 150-400 km, which may be the remnant of a delamination process which resulted in the decratonization of the North China and the Yangtze cratons. Receiver functions from several dense seismic arrays traversing different parts of the Tibetan plateau reveals the boundary between the Indian and Eurasian tectonic plates. A particular lithospheric region is defined in NE Tibet as a crush zone between the two colliding plates, the existence of which is marked by high temperature, low mantle seismic wavespeed, poor Sn propagation, east and southeast oriented GPS displacements and strikingly larger SKS anisotropy.
Publications
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2010, Details of the doublet Moho structure beneath Lhasa, Tibet obtained by comparison of P and S receiver functions, Bull. Seismol. Soc. Am., 101, 1259-1269
Li, X., D. Wei, X. Yuan, R. Kind, P. Kumar and H. Zhou
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2010, Seismic images of the biggest crash on earth, Science, 329, 1479-1480
Kind, R. and X, Yuan
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2010, Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin, Earth Planet. Sci. Lett., 292, 254-264
Zhang, Z., X. Yuan, Y. Chen, X. Tian, R. Kind, X. Li and J. Teng
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2010, The boundary between the Indian and Asian tectonic plates below Tibet, Proc. Nat. Acad. Sci., 107, 11229-11233
Zhao, J., X. Yuan, H. Liu, P. Kumar, S. Pei, R. Kind, Z. Zhang, J. Teng, L. Ding, X. Gao, Q. Xu and W. Wang
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Normal faulting from simple shear rifting in South Tibet, using evidence from passive seismic profiling across the Yadong-Gulu Rift, Tectonophysics, 606, 178-186
Zhang, Z., Y. Chen, X. Yuan, X. Tian, S.L. Klemperer, T. Xu, Z. Bai, H. Zhang, J. Wu and J. Teng
