Abstract
We present results of a tomographic inversion of teleseismic data
recorded at 48 stations of a temporary network which was installed
in the area of the Dead Sea Transform (DST) and operated for 1 yr
in the framework of the multidisciplinary DESERT Project. The 3366
teleseismic P and PKP phases from 135 events were hand picked and
corrected for surface topography and crustal thickness. The inversion
shows pronounced low-velocity anomalies in the crust, beneath the
DST, which are consistent with recent results from local-source tomography.
These anomalies are likely related to the young sediments and fractured
rocks in the fault zone. The deeper the retrieved anomalies are quite
weak. Most prominent is the high-velocity strip-like anomaly striking
SE-NW. We attribute this anomaly to the inherited heterogeneity of
lithospheric structure, with a possible contribution by the shallow
Precambrian basement east of the DST and to lower crustal heterogeneity
reported in this region by other seismic studies. We do not observe
reliable signature of the DST in the upper mantle structure. Some
weak indications of low-velocity anomalies in the upper mantle beneath
the DST may well result from the down-smearing of the strong upper
crustal anomalies. We also see very little topography of the lithosphere-asthenosphere
boundary beneath the DST, which would generate significant horizontal
velocity variations. These results are consistent with predictions
from a recent thermo-mechanical model of the DST. Our tomographic
model provides some indication of hot mantle flow from the deeper
upper mantle rooted in the region of the Red Sea. However, resolution
tests show that this anomaly may well be beyond resolution of the
model.
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