Subsurface imaging of the eastern Ramon fault, Wadi Neqarot, south Israel

The Ramon fault is a major element within the Central Sinai-Negev shear zone, extending across the Negev and central Sinai, from the Dead Sea Transform (DST) to the Gulf of Suez. Right lateral strike-slip motion, dated as post early Miocene, has been recorded along several elements of this system. Some evidence of earlier activity has been noticed along several faults belonging to this system, but only in few cases the nature of this activity is known. The eastern part of the Ramon fault from Wadi Geled to the DST is known from surface geology as a high angle reverse fault. A vertical separation of almost 200 meters is based on lower Cretaceous sandstone abutting upper Cretaceous units. Recent seismic lines carried out across the eastern segment of the Ramon fault reveal new information from subsurface concerning the geometry and history of the Ramon fault zone. We suggest two alternative models to image the subsurface, both leaning on interpretation of seismic lines across the fault. No other subsurface stratigraphic information apart from a distant borehole was available to this research. The first model show three phases of deformation: I. Post Triassic tensional phase, forming normal fault. This fault changes its inclination from a sub vertical angle at surface to a sub horizontal within few hundred meters. II. Compressional phase, during the late Cretaceous, which recorded by a thicker section of units at south of the fault compared to northern part. III. Deformation which took place after early Miocene, and based on surface geology. The second model based on structural considerations and consists of two phases of deformation I. Post Triassic normal fault, which form a listric fault within few hundred meters. II. Post Miocene reverse faulting, which is a reactivation phase along same fault plane that is also responsible for the antithetic reverse faults.