HR: 11:50h
AN: S42A-07    [Abstracts]
TI: Shear Wave Splitting Observations Beneath the Iranian Plateau
AU: * Kaviani, A
EM: akaviani@iasbs.ac.ir
AF: Institute for Advanced Studies in Basic Sciences (IASBS), P. O. Box 45195-1159, Zanjan, 45195, Iran (Islamic Republic of)
AU: * Kaviani, A
EM: akaviani@iasbs.ac.ir
AF: International Institute of Earthquake Engineering and Seismology (IIEES), P. O. Box 19395- 3913, Tehran, 19395, Iran (Islamic Republic of)
AU: * Kaviani, A
EM: akaviani@iasbs.ac.ir
AF: Laboratoire de Géophysique Interne et de Tectonophysique, CNRS, Université Joseph Fourier, P. O. Box 53, Grenoble, 38041, France
AU: Hatzfeld, D
EM: Denis.Hatzfeld@obs.ujf-grenoble.fr
AF: Laboratoire de Géophysique Interne et de Tectonophysique, CNRS, Université Joseph Fourier, P. O. Box 53, Grenoble, 38041, France
AU: Paul, A
EM: Anne.Paul@obs.ujf-grenoble.fr
AF: Laboratoire de Géophysique Interne et de Tectonophysique, CNRS, Université Joseph Fourier, P. O. Box 53, Grenoble, 38041, France
AU: Tatar, M
EM: mtatar@iiees.ac.ir
AF: International Institute of Earthquake Engineering and Seismology (IIEES), P. O. Box 19395- 3913, Tehran, 19395, Iran (Islamic Republic of)
AU: Priestley, K
EM: keith@esc.cam.ac.uk
AF: Department of Earth Sciences, University of Cambridge, Downing Street, CAMBRIDGE, CB2 3EQ, United Kingdom
AB: Recordings of teleseismic events from 69 three-component stations deployed over the Iranian Plateau were used for shear wave splitting studies. No significant splitting was measured in Zagros, Kopet-Dagh and NW Iran suggesting absence of any coherent anisotropic fabric or presence of complexities in the upper mantle beneath these tectonic regions leading to the null splitting for shear-waves. Intricate splitting patterns with varying fast directions were observed in Central Alborz implying presence of complex anisotropic fabrics. On the other hand, time lags greater than 0.8 sec with a general NW-SE fast polarization direction were observed in a narrow zone in Central Iran. Inhomogeneous splitting pattern over the Iranian Plateau excludes mantle shearing induced by present-day absolute motion of the Plateau as being the cause of the observed shear wave splitting. Rather, we suggest that the observed splitting pattern in Central Iran is related to the mantle flow associated with the relative motion of Arabian lithosphere with respect to the Central Iranian blocks.
DE: 7205 Continental crust (1219)
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7218 Lithosphere (1236)
DE: 7220 Oceanic crust
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Seismology [S]
MN: 2007 Fall Meeting