HR: 12:05h
AN: S32A-08 [Abstracts]
TI: Anisotropy in Crust and Upper Mantle Beneath China Continent and its Adjacent Seas
AU: * Peng, Y
EM: pengyj408@126.com
AF: Yanju Peng, No.1, Anning Road, Haidian District, Beijing, 100085, China
AU: Huang, Z
EM: zhxhuang@163.com
AF: Yanju Peng, No.1, Anning Road, Haidian District, Beijing, 100085, China
AU: Lu, Y
EM: luyj1@263.net
AF: Yanju Peng, No.1, Anning Road, Haidian District, Beijing, 100085, China
AU: Zhang, R
EM: rqzhang@163.com
AF: Ruiqing Zhang, No.5, Minzudaxue Road, Haidian District, Beijing, 100081, China
AB:
Using the difference of S wave velocity structures derived respectively from Love and Rayleigh wave, the
polarization anisotropy in crust and upper mantle beneath China continent and adjcent seas is studied. The
result indicates that the distribution of anisotropy is spatially uneven. (a) The VSH>VSV anisotropy is dominant
in the upper 150km, which indicates the horizontal stress in shallower lithosphere and the horizontal mass flow
in upper asthenosphere are the leading factors in the formation of polarization anisotropy. In the land area the
anisotropy intensity changes markedly with depth. The anisotropy in upper crust and upper mantle lid is widely
much weak, while the anisotropy is intense in the rheological intense lower crust and ashenosphere, which
indicates the lower crust may decouple in the lithosphere deformation. (b) VSH<VSV anisotropy is the main
characteristic of the lower asthenosphere beneath 200km, which reflects the vertical movement of the mantle
mass. (c) The overall picture in eastern China continent is: in stable blocks VSH>VSV anisotropy is more
prominent in lithosphere and VSH<VSV anisotropy is weaker in asthenosphere, in tectonically active areas it is
on the contrary. (d) In western China the anisotropy is apparently related to the subduction of India plate beneath
Tibet. The conspicuous VSH>VSV anisotropy is the result of the collision and compression between India plate
and Eurasian continents which makes the mantle material recrystalize orientationally.
DE: 1213 Earth's interior: dynamics (1507, 7207, 7208, 8115, 8120)
DE: 3285 Wave propagation (0689, 2487, 4275, 4455, 6934)
DE: 7205 Continental crust (1219)
DE: 7209 Earthquake dynamics (1242)
SC: Seismology [S]
MN: 2007 Fall Meeting