HR: 14:55h
AN: T23F-06    [Abstracts]
TI: Crustal and mantle velocity models of southern Tibet from finite frequency tomography
AU: * Liang, X
EM: airwolf_l@163.com
AF: Peking University, Department of Geophysics School of Earth and Space Sciences, Beijing, 100871, China
AU: Shen, Y
EM: yshen@gso.uri.edu
AF: University of Rhode Island, Graduate School of Oceanography, Narragansett, RI 02882, United States
AU: Chen, Y J
EM: johnyc@pku.edu.cn
AF: Peking University, Department of Geophysics School of Earth and Space Sciences, Beijing, 100871, China
AB: The formation of the Himalayan Range and Tibetan plateau has broad implications for earth sciences. Yet the exact mechanisms of the mountain-building processes, in particular, the roles of the Tibetan mantle lithosphere and upper mantle in the rise of the plateau, remain poorly constrained. Most of the previous seismic experiments in southern Tibet consisted of north-south trending linear arrays, thus provided very limited constraints on the east-west variations in the crustal and mantle structure beneath the region. As an addition to the international Hi-CLIMB project, a temporary, 2D array of 37 seismic stations was installed between Tingri and Xigaze in southern Tibet and operated from June 2004 to August 2005 by Peking University, China Academy of Geological Sciences, and Institute of Earthquake Sciences, Academia Sinica. We measured traveltimes of teleseismic body waves recorded by this array by waveform cross-correlation and carried out finite-frequency tomography inversions to image the 3-D velocity structure beneath southern Tibet. The preliminary results reveal strong lateral P-velocity variations (3-4%) at depth above 200 km, and a region of relatively high P-wave velocity extending continuously from the uppermost mantle to 350 km depth beneath southern Tibet. Interpretation of these findings and their implications for the current dynamics models of Tibetan plateau will be discussed.
DE: 7218 Lithosphere (1236)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: 2007 Fall Meeting