IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS014 Poster presentation 2317
P-Wave velocity perturbations of the crust beneath Georgia
Dr. Tea Mumladze
Seismic Data Processing Seismic Monitoring Centre of Georgia
We determined the first high-resolution tomographic image of the crust beneath applying the local
tomography method of Zhao et al. (1992). The study area was divided into four layers vertically and a
3-D grid net was set up in the modeling space. Velocities at grid nodes were taken as unknown
parameters. The velocity at any point in the model was computed by linearly interpolating the velocities
at the eight grid nodes surrounding that point. The grid spacing was 30 km in the horizontal and 5 to 20
km in the vertical direction, respectively. We used 78,454 P and 67,105 S wave arrival times from 6750
earthquakes recoded by 98 seismic stations of the regional seismic network of and seismic networks of
and . Our results show strong lateral heterogeneity in the crust under and correlation among the
velocity variations, seismicity, active faults, and Quaternary volcanic centers. Our tomography image of
the uppermost mantle reflects the depth variation of the Moho discontinuity.
Keywords: crust, structure, velocity