Waveform modeling of short-scale shear-wave splitting variations across the Dead Sea basin
Abstract
The Dead Sea basin forms the largest pull-apart basin along the Dead Sea transform fault. As part of the DESIRE project, we investigate the seismic anisotropy across the Dead Sea basin to study mantle deformation processes. We examine shear-wave splitting of SKS waveforms collected by a temporary array of 68 stations along the Dead Sea basin. The observed splitting parameters (i.e. the delay time between the fast and slow shear waves and the polarization direction of the fast shear wave) exhibit systematic variations along an EW-trending profile across the basin. The delay times vary between 1.0 and 2.8 seconds and are among the largest observed in the world. The fast polarizations are oriented more-or-less parallel to the strike of the Dead Sea transform fault and vary between -10 and 20 degrees with respect to North. Full finite-difference waveform modeling reveals that the source-region of the small-scale lateral variations is likely located within the crust. The modeling further shows that purely isotropic velocity variations can affect shear-wave splitting. To a large degree, the observed variations of splitting parameters can be explained by the sedimentary fill of the basin and its low seismic velocities. Our study indicates that precaution must be taken when interpreting short-scale lateral variations of shear wave splitting in terms of anisotropic structures in the crust or upper mantle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMDI13A1847K
- Keywords:
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- 0545 COMPUTATIONAL GEOPHYSICS / Modeling;
- 7200 SEISMOLOGY;
- 7250 SEISMOLOGY / Transform faults;
- 8111 TECTONOPHYSICS / Continental tectonics: strike-slip and transform