HR: 0830h
AN: S31E-0801    [PDF]
TI: Teleseismic tomography of the upper mantle beneath China
AU: * Zor, E
EM: ekrem@nmsu.edu
AF: Department of Physics New Mexico State University, 254 Gardiner Hall, Las Cruces, NM 88003
AU: Hearn, T M
EM: thearn@nmsu.edu
AF: Department of Physics New Mexico State University, 254 Gardiner Hall, Las Cruces, NM 88003
AU: Ni, J F
EM: jni@nmsu.edu
AF: Department of Physics New Mexico State University, 254 Gardiner Hall, Las Cruces, NM 88003
AB: Seismic P-wave velocity variations in the upper mantle beneath China are tomographically imaged using P-wave traveltime data reported in the Bulletin of Seismological Observations of China. This data set is compiled by the China Seimological Bureau. Within the lithosphere, low velocities are observed beneath the Northeast China basin and the back-arc Yunan province. These regions are affected by late Cenozoic extension. Low velocities beneath the Northeast China basin extend down to roughly 300 km suggesting the involvement of the asthenosphere. The eastern Himalayan syntaxis is underlain by Indian shield which has fast velocity. The Sichuan basin is a stable cratonic shield and is characterized by high velocity in the upper 200 km. A high velocity zone at 150-250 km depth is imaged beneath the Qiling-Dabie suture, which was a late Triassic collision zone between the North and South China blocks. The high velocity indicates a thickened lithosphere duing the collision. The lithosphere of the South China block has a relatively high velocity.The subducted Pacific plate beneath North Korea is revealed by the tomographic image. A very low velocity anomaly, perhaps a plume, is imaged beneath southeastern China in a region just north of the Hainan Island.
DE: 7200 SEISMOLOGY
DE: 7218 Lithosphere and upper mantle
SC: Seismology [S]
MN: 2003 Fall Meeting