Geophysical Studies of the Crustal Structure Along the Southern Dead Sea Fault

Abstract

The Dead Sea Fault (DSF) is an active transform fault linking opening in the Red Sea with collision in the Taurus/Zagros Mountains. Motion is left-lateral and estimated at approximately 5–7 mm/year. The fault is seismically active. The extensional regime combined with the dominant lateral motion along the DSF resulted in the formation of a series of deep pull-apart basins. These basins are among the largest and deepest in the world. The crustal structure of the DSF and its surroundings played a significant role in the development of the physiography and the architecture of the basins. The subsurface structure of the southern DSF has been studied quite intensively by various geophysical methods over the past few decades. This review summarizes the main geophysical findings of the crustal structure under the deep basins along the southern DSF, comparing the three deep basins against each other in contexts of various geophysical properties, and discussing their tectonic implications. A simulation of faulting processes along the northern DSF and the Levant margin suggested that the formation of the DSF could be explained as a result of simultaneous propagation from the north and south. Normally most basins are bordered only on one side by a strand of the DSF, leading to their asymmetry. Where asymmetry occurs basins do not extend to great depth. In areas where the deep basins occur, two strands of the DSF overlap in an en-echelon pattern. This situation is quite rare along the DSF. It is suggested that in these places an isolated block of lithosphere has dropped into the mantle. Simulations of this mechanism indicate that the resulting basin is rhomb-shaped and that with time it grows by the addition of distinct segments to its edges.