
Holocene slip rates across the Amazyahu Fault
Asif O. (1, 2), Mushkin A. (1), Langford B. (1, 2), Balmas A. (1), Vaks A. )1(, Frumkin A. (2)
(1) Geological Survey of Israel, 32 Yesha'ayahu Leibowitz, Jerusalem 9692100, Israel
(2) The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Israel
The Amazyahu Fault is a tectonic lineament that strikes WNW over a distance of 16 km and cuts through the Lisan and Samra sediments at the southern border of the Dead Sea basin. Although classified as an active normal or listric fault, its geologic slip rates have not been previously quantified. To address this knowledge gap, we conducted a detailed field survey of abandoned alluvial terraces that were either: 1) offset by the fault itself or 2) were incised in response to fault activity that lowered the base-level of streams flowing across the fault. All together 7 terraces were mapped and subsequently dated with either luminescence or radiocarbon analyses. Our results revealed spatial variability in faulting activity, ranging from ~2 m of vertical offset since 8000 yr BP near the fault’s northwestern termination to 14.5 m of vertical offset since 5000 BP along the fault’s central segment. In general, all the terraces along the central segment of the fault displayed a robust correlation between their elevation above the active channel and terrace age, and consistently point towards a time-invariant vertical slip rate of at least ~3 mm/yr since the mid-Holocene. This relatively high slip rate suggests a possible involvement of salt deformation in the Holocene offset accommodated by the Amazyahu Fault.