HR: 1340h
AN: T13A-0449    [Abstracts]
TI: Lithosperic Structure of the Arabian Peninsula From Joint Inversion of Teleseismic Receiver Functions and Surface Waves
AU: * Tkalcic, H
EM: tkalcic1@llnl.gov
AF: Lawrence Livermore National Laboratory, The Atmospheric, Earth and Energy Sciences L-206, P.O. Box 808, Livermore, CA 94550 United States
AU: Pasyanos, M E
T13A-0449 AF: Lawrence Livermore National Laboratory, The Atmospheric, Earth and Energy Sciences L-206, P.O. Box 808, Livermore, CA 94550 United States
AU: Rodgers, A J
T13A-0449 AF: Lawrence Livermore National Laboratory, The Atmospheric, Earth and Energy Sciences L-206, P.O. Box 808, Livermore, CA 94550 United States
AU: Gok, R
T13A-0449 AF: Lawrence Livermore National Laboratory, The Atmospheric, Earth and Energy Sciences L-206, P.O. Box 808, Livermore, CA 94550 United States
AU: Walter, W R
T13A-0449 AF: Lawrence Livermore National Laboratory, The Atmospheric, Earth and Energy Sciences L-206, P.O. Box 808, Livermore, CA 94550 United States
AU: Al-Amri, A M
T13A-0449 AF: King Saud University, Department of Geology, P.O. Box 2455, Riyadh, 11451 Saudi Arabia
AU: Al-Enezi, A
T13A-0449 AF: Kuwait Institute for Scientific Research, Environment and Urban Development, Safat, 13109 Kuwait
AB: With a goal of improving structural estimates of the Eurasian lithosphere, Lawrence Livermore National Laboratory (LLNL) has collaborative projects with a number of institutions in the Middle East. This has given us a unique opportunity to study Earth's structure below these regions. One of the widely used types of measurements to study lithospheric Earth's structure is surface-wave dispersion, from which 3-D variations in seismic velocities could be obtained. In this study we use a combination of grid search and iterative inversion scheme to fit jointly the surface wave group velocity dispersion (from 7 to 100 seconds for Rayleigh and 20 to 70 seconds for Love waves) and the receiver functions for the broadband stations installed on the Arabian Peninsula. For the grid search we use a database of pre-calculated theoretical receiver functions and dispersion curves, which allows us to significantly reduce the computing time and investigate wide range of structural models. We initially fit receiver functions and shorter periods of the observed dispersion curves with the structure within the crust and immediately under the crust. We then use an additional grid search to characterize the lithospheric lid and low velocity zone in the upper mantle, fitting longer periods of the dispersion curves. Results for several stations located in the Arabian Shield confirm crust thinning near the Red Sea and thickening towards the Arabian interior, which is consistent with previous studies. However our results indicate the presence of polarization anisotropy in the lithospheric upper mantle, even further away from the Red Sea than previously reported. Without invoking anisotropy, it is not possible to jointly explain the observed receiver functions and Love and Rayleigh wave dispersion discrepancy.
DE: 7205 Continental crust (1219)
DE: 7218 Lithosphere (1236)
DE: 7255 Surface waves and free oscillations
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005