ESTIMATING THE AGES OF FAULT SCARPS IN THE ARAVA, ISRAEL

Systematic age estimations for the numerous fault scarps that rupture the alluvial fans in the southern Arava valley, Israel, are rare or no nexistent. Here we estimate the morphologic ages of several of these f aults by the fault scarp degradation method and show that the ages agr ee well with ages estimated by the independent, earlier soil-geomorphi c studies. The values we use for the coefficient of diffusion for the fault scalp degradation process are calibrated by a few numerical ages . These ages were determined by the Infrared Stimulated Luminescence ( IRSL) method on one of the fault scarps and are the only numerical age s in the region. The morphologic ages are all in a correct stratigraph ic order and in agreement with field stratigraphic relationships deter mined by earlier studies. They indicate that the studied fault scarps range in age from the latest Pleistocene to very recent times. The mos t recent fault scarps, which were analyzed are less than 2000 years ol d and perhaps much younger. They indicate that at least two earthquake s with magnitude > 6.5 have affected southern Israel and Jordan during that period. It is emphasized that so far we have studied only a limi ted number of fault scarps and therefore the number of large earthquak es during the last one to two millennia is a minimum.