Nature of slip transfer between strike-slip faults: The Eastern Sinai (Egypt) shear zone, Dead Sea Transform

Abstract

The western margin of the Gulf of Elat (Aqaba), a sector of the Dead Sea Transform, is characterized by an N–S striking shear zone with cumulative sinistral (left-lateral) offset of 24 km. The crystalline basement in the study area is unique in its excellent rock and fault exposures forming a >50 km long, shear zone with abundant offset of linear features as well as the contact of the basement with the Infracambrian sub-horizontal peneplain. These features enable accurate measurement of the horizontal and vertical displacements along the major and secondary faults to ±50 m. The small vertical offset of the peneplain surface and a measurement of about 8° net-slip plunge along one of the major faults suggest that along all strike-slip faults, movement was almost pure horizontal slip. Part of this horizontal slip was transferred to neighboring major strike-slip faults by secondary strike-slip faults with negligible loss of displacement. The amount of horizontal slip transferred by normal faults, even in releasing bends, is small due to the high dip angle of these faults. Wide breccia zones and distributed deformation of a small fraction of the horizontal slip is observed when the angle between the strike-slip faults exceeds 30°.