First images from the bottom of the Dead Sea - Indications of recent tectonic activity

The two-man submersible Delta, which dove in the north end of the northern Dead Sea basin during December 1999, revealed indications of recent tectonic activity along the Jericho fault, a major strand of the Dead Sea transform in the area. The fault is expressed by steep (70°-90°) vertical cliffs that are covered by layers of salt. Marl is observed in areas where salt has been chipped away. Recent activity is inferred by the observation of an open interface between the sea floor and the vertical cliff, which is the underwater expression of the Jericho fault. Differences in salt crystal size between the vertical wall and surrounding areas (from 2-3 mm on the surface to 5 cm at the interface), along with the presence of suspected halophilic microorganisms, suggest seepage of fresher water through cracks along the fault zone-again suggesting active faulting.