Prehistoric earthquake deformations near Masada, Dead Sea graben

Earthquake-induced fluidizations and suspensions of lake sediments, associated with syndepositional faults, form a paleoseismic record in the Dead Sea graben. The association of fluidized beds with surface faulting supports the recognition of mixed layers as reliable earthquake indicators and provides a tool for the study of very long term (>70 kar) seismicity along the Dead Sea transform. The faults compose a fault zone that offsets laminated sediments of the late Pleistocene Lake Lisan. They exhibit displacements of as much as 2 m. Layers of massive mixtures of laminated fragments are interpreted as disturbed beds, each formed by an earthquake. The undisturbed laminated layers between these mixed layers represent the interseismic interval. A typical vertical slip of about 0.5 m per event is separated by several hundred years of quiescence. The fault zone lies within the Dead Sea graben 2 km east of Masada, where archaeology and historical accounts indicate repeated strong earthquake damage. -from Authors