HR: 12:10h
AN: T52A-08    [Abstracts]
TI: P-wave velocity variation in the upper mantle beneath Tibetan Plateau
AU: * Li, C
EM: changli@mit.edu
AF: Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: van der Hilst, R
EM: hilst@mit.edu
AF: Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 United States
AU: Chen, Z
EM: zhiliang@cigmr.org
AF: Chengdu Institute of Geology and Mineral Resources, Renmin Road, Chendu, SC 610000 China
AU: Anne, M
EM: ameltzer@lehigh.edu
AF: Earth and Environmental Sciences Lehigh University, 31 Williams Drive, Bethlehem, PA 18015 United States
AB: We produced a P-wave model of the upper mantle beneath Tibeatan Plateau from a combination of International Seismological Centre (ISC) P and pP data, processed by Engdahl et al. (1998), P data of the Annual Bulletin of Chinese Earthquake (ABCE) [IG-CSB, 1990-1998], and travel times of P phases recorded at temporary arrays around Tibetan Plateau, including arrays operated by (a) MIT and the Chengdu Institute of Geology and Mineral Resources (MIT-CIGMR) - 09/2003-09/2004; (b) Lehigh university and CIGMR - 07/2003-10/2004; (c) the INDEPTH (InterNational DEep Profiling of Tibet and the Himalaya) project - 05/1994-10/1994, 07/1997-06/1999; and (d) various French and Chinese groups - 07/1991-06/1992. Incorporating the travel times of phases recorded at arrays allow us to constrain upper mantle structure with much greater resolution and confidence than before, and the preliminary models reveal intriguing variations in P-wavespeed in the upper mantle beneath Tibetan Plateau. Our images suggest that the Indian lithosphere subducts from the foreland basin and underlies only the southwestern margin of the Tibetan Plateau, implying that much of the Tibetan Plateau is not underlain by Indian but by Asian lithosphere. Some of the seismically slow structures beneath the eastern part of the plateau may connect to structures, and presumably, processes in the upper mantle beneath the South China Sea.
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7270 Tomography (6982, 8180)
DE: 7294 Seismic instruments and networks (0935, 3025)
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005