Clastic dikes in the Dead Sea basin as indicators of local site amplification

Abstract

Early Holocene seismic activity triggered fluidization and clastic-dike emplacement within Late Pleistocene lacustrine Lisan Formation sediments in the Dead Sea basin (DSB). Hundreds of opening-mode clastic dikes were documented cross-cutting the Lisan Formation in four distinct sites in relatively small ( 6.5). The injection of clastic dikes in distinct and relatively small areas in the Lisan Formation along the DSB may serve as evidence for a unique combination of three factors: (a) clay-rich sediments and high water table as favorable conditions for fluidization on the exposed surface following the Lake Lisan regression; (b) the occurrence of moderate-to-strong earthquakes (M w > 6) in the early Holocene after the deposition of the Lisan Formation; and (c) the local geological structure characterized by edge and basin effects, which can amplify seismic waves. The present study indicates that injection due to fluidization of clay-rich strata during earthquakes was dominant throughout the DSB. We suggest that the clastic dikes can serve as evidence for local amplification conditions following seismic processes that occur close to active faults.