HR: 0800h
AN: S41C-1010    [Abstracts]
TI: Joint Inversion for Bulk Sound and Shear Wave Velocity Heterogeneity Beneath the Mediterranean Plate Boundary Region
AU: Schmid, C
EM: chrischm@student.ethz.ch
AF: Inst. Of Geophysics ETH Zuerich, ETH Hoenggerberg / HPP, Zuerich, 8093 Switzerland
AU: * Van der Lee, S
EM: suzan@earth.northwestern.edu
AF: Department of Geological Sciences Northwestern University, 1850 Campus Drive, Evanston, IL 60208-2150 United States
AU: Giardini, D
EM: giardini@sed.ethz.ch
AF: Inst. Of Geophysics ETH Zuerich, ETH Hoenggerberg / HPP, Zuerich, 8093 Switzerland
AU: Giardini, D
EM: giardini@sed.ethz.ch
AF: Department of Geological Sciences Northwestern University, 1850 Campus Drive, Evanston, IL 60208-2150 United States
AB: We present new 3-D models for shear wave and compressional wave velocity anomalies for the mantle beneath the Mediterranean plate boundary region down to a depth of ~1500 km. These new models are based on a combined set of P and S body-wave arrival time data, which was measured by interstation cross-correlation. Stations used were from the MIDSEA deployment and permanent networks in the region. We invert these data jointly for bulk sound and shear wave velocity heterogeneity. The resulting models of P and S velocity heterogeneity are similar to each other. P wave velocity heterogeneity appears to be dominated by variations in shear modulus. We do not find evidence for large scale anti-correlation between bulk sound and shear wave velocity heterogeneity. We further constrain the mantle's S-velocity with regional S and surface waves and Moho detections. The Mediterranean region is substantially slower than the global average at shallow mantle depths and faster than average at transition zone depths. Our models show high velocities related to present and recent subduction northwards beneath the Hellenic trench, northwestwards beneath the Calabrian Arc, and a much shorter slab dipping southwestwards beneath the Apennines. Our models show somewhat surprising evidence of past subduction in the transition zone beneath the western Mediterranean and in the lower mantle beneath northeastern Africa. The only significantly slower region at transition zone depths is found beneath the Ionian Sea.
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 7270 Tomography (6982, 8180)
DE: 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105)
DE: 8150 Plate boundary: general (3040)
SC: Seismology [S]
MN: Fall Meeting 2005