HR: 11:35h
AN: S42A-06    [Abstracts]
TI: Upper mantle shear wave velocity structure of the Arabian Shield from teleseismic surface wave tomography
AU: Park, Y
EM: ypark@geosc.psu.edu
AF: The Pennsylvania State University, 426 Deike Building, Univeristy Park, PA 16802, United States
AU: * Nyblade, A A
EM: andy@geosc.psu.edu
AF: The Pennsylvania State University, 426 Deike Building, Univeristy Park, PA 16802, United States
AU: Rodgers, A J
EM: rodgers7@llnl.gov
AF: Lawrence Livermore National Laboratory, Geophysics and Global Security Devision, P.O.Box 808, Livermore, CA 94551, United States
AU: Al-Amri, A
EM: amsamri@ksu.edu.sa
AF: King Saud University, P.O.Box 2455, Riyadh, 11451, Saudi Arabia
AB: We investigate the seismic shear wave velocity structure of the shallow upper mantle beneath the Arabian Shield by inverting Rayleigh wave phase velocity measurements between 44 and 140 s together with previously published Rayleigh wave group velocity measurements between 10 and 50 s from Pasyanos. The Rayleigh wave phase velocity measurements between 44 and 140 s have been made using teleseismic earthquake data mainly from the Saudi Arabia National Digital Seismic Network (SANDSN) or Saudi Arabian PASSCAL experiment. A model of upper mantle structure beneath the Arabian Shield obtained from Rayleigh wave phase velocity tomography shows a broad low velocity region in the lithospheric mantle across the Shield and a low velocity region at depths > 150 km localized along the Red Sea coast and MMN volcanic line. The estimated thickness of the lithosphere from the model is ~90-100 km beneath the southern part of the Shield, ~70 km beneath the northern Shield under the MMN volcanic line, and ~100 km near the Platform boundary. These finding, in particular the region of continuous low velocities along the Red Sea and MMN volcanic line, do not support interpretations for the origin of the Cenozoic plateau uplift and volcanism on the Shield invoking two separate plumes. When combined with images of the 410 and 660 km discontinuities beneath the southern part of the Arabian Shield, body wave tomographic models, and a S-wave polarization analysis, the model presented in this study can be used to support geodynamic interpretations invoking a single large plume or a Superplume to explain the Cenozoic hotspot tectonism on the Arabian Shield.
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7270 Tomography (6982, 8180)
DE: 8180 Tomography (6982, 7270)
SC: Seismology [S]
MN: 2007 Fall Meeting