HR: 0940h
AN: V41G-07    [Abstracts]
TI: Seismic Evidence for the Hainan Plume
AU: * Lei, J
EM: leijs@hotmail.com
AF: Institute of Crustal Dynamics, China Earthquake Administration, Xisanqi, Haidian District, Beijing, 100085, China
AU: Zhao, D
EM: zhao@aob.geophys.tohoku.ac.jp
AF: Department of Geophysics, Tohoku University, 6-6 Aza-Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AB: We present a high-resolution tomographic image in the upper mantle for the Hainan plume determined by using both local and teleseismic data. The arrival time data from teleseismic events are measured precisely from seismograms recorded by nine permanent seismic stations in Hainan island and Leizhou peninsula. Our results show that striking low-velocity (low-V) anomalies of up to -5 percent in the crust and -2 percent in the mantle are visible under the Hainan hotspot from the surface down to 300 km depth. The Hainan plume is imaged as a continuous, NW-SE tilting, low-V column with a diameter of about 80 km. This image of the Hainan plume is much improved over the results of the previous regional and global studies. Such an inclination of the plume is in good agreement with the results of numerical simulations and paleomagnetic studies. The Hainan plume deflection may be partly attributed to the upper mantle shear flow resulted from the complex subduction and interaction of the Indian, Philippine Sea, Pacific and Eurasian plates.
UR: http://www.eq-icd.cn
DE: 7280 Volcano seismology (8419)
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
DE: 8180 Tomography (6982, 7270)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting