Slip rate and locking depth from GPS profiles across the southern Dead Sea Transform
Résumé
The Dead Sea Transform is a major strike-slip fault bounding the Arabia plate and the Sinai subplate. On the basis of two GPS campaign measurements, 6 years apart, at 17 sites distributed in Israel and Jordan, complemented by Israeli permanent stations, we compute the present-day deformation across the southern segment of the Dead Sea Transform, the Wadi Araba fault. Elastic locked-fault modeling of fault-parallel velocities provides a slip rate of 4.9 ± 1.4 mm/a and a best fit locking depth of $12 km. This slip rate is slightly higher than previous results based only on Israeli permanent GPS stations data, which are located west of the fault. It is in good agreement with results based on offset geomorphologic and geologic features that average longer periods of time (10 ka to 1 Ma). Projection in ITRF2000 reference frame allows using our data, combined with results published earlier, to further study the kinematics between Arabia, Nubia, and Sinai. Systematic combination of Euler poles available in the literature, in addition to our new set of data, shows that a wide range of Arabia-Sinai pole positions and angular velocities predict reasonable slip rate on the Dead Sea fault. We highlight uncertainties of calculating such poles due to the small size of the blocks and their slow relative motion along a short and almost straight strand of the transform fault, which lead to a large trade-off between pole location and angular velocity.
Domaines
Tectonique
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