HR: 0830h
AN: S31E-0795    [PDF]
TI: High resolution P-wave tomography for SE Romania - an earthquake prone region in SE Europe
AU: * Martin, M
EM: Michael.Martin@gpi.uni-karlsruhe.de
AF: Geophysical Institute, Hertzstr. 16, Karlsruhe, 76187 Germany
AU: Wenzel, F
EM: Friedemann.Wenzel@gpi.uni-karlsruhe.de
AF: Geophysical Institute, Hertzstr. 16, Karlsruhe, 76187 Germany
AB: The Vrancea earthquake region in SE Romania is characterized by strong intermediate depth seismicity in a very limited and well defined hypocentral region. Previous studies recognized a high velocity body as locus of the intermediate depth seismicity. Present models interpret this body as a remnant of subducted lithosphere that has been detached along the Carpathian arc, now representing the final stage of slab break-off in the upper mantle. For our new results we used the teleseismic dataset of the CALIXTO tomography experiment for a nonlinear inversion of teleseismic P-wave traveltimes. The dataset consists of more than 12 000 handpicked traveltime readings from 196 events leading to a good ray coverage within the model. In previous results the influence of the poorly resolved crust caused uncontrolled smearing into the upper mantle. To overcome this limitation traveltimes were calculated through a realistic 3D crustal model for this region with a 3D-FD raytracing algorithm. Therefore the effect of the traveltime anomalies within the crust could be eliminated from the tomographic inversion. We will present high resolution images of the high velocity body and the surroundings in the upper mantle as the results of nonlinear teleseismic tomography and discuss it in terms of structure, resolution capability and solution reliability and therefore outline the boundary conditions for the geodynamic processes of this region.
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
DE: 7218 Lithosphere and upper mantle
DE: 7230 Seismicity and seismotectonics
DE: 8180 Tomography
SC: Seismology [S]
MN: 2003 Fall Meeting