The Dead Sea basin is an active seismogenic zone. The tectonic activity in its northern part is concentrated along the Jericho fault. It is mapped from the lake`s northern shore at Kaliyah beach up to the Allenby Bridge (King Hussein) border crossing. The fault ruptures late Pleistocene and Holocene sediments. There are different infrastructures located in the proximity of fault. Therefore, establishing, whether the fault is active, is crucial. Previous works dated the seismic activity on the Jericho fault to the middle-late Holocene using stratigraphic relationships, archeological findings (pottery artifacts), and radiometric dating by 14C and optically stimulated luminescence (OSL, on large aliquots). Yet, the slip rate and the structural characteristic of the movement along the fault is not clear.
The OSL method dates the last exposure of quartz grains to sunlight before their burial. This technique can frame faulting events in time by dating the ruptured and the overlaying sediments. Here we present new ages from two sites exposing the Jericho fault: a trench, and two erosional channels south to the Allenby border crossing. The exposed unites present a complex stratigraphy composed of lacustrine and fluvial sediments, covered by soils. The sedimentary units in both locations are crossed by a roughly 150 m wide zone of fault branches and tilted blocks, demonstrating a complex earthquakes history. Sixteen samples were dated by OSL, representing the different sedimentary unites.
All samples contain fine sand quartz required for dating. Most of them have a narrow distribution of the equivalent dose values (De), indicating full signal bleaching at deposition. The sedimentary unites from the two sites were dated to ~0.3-20 ka. In agreement with previous studies, our preliminary results show that the Jericho fault was active several times in the late Holocene. An updated structural analysis will be presented.