Relation between radon concentrations and morphotectonics of the Dead Sea transform in Wadi Araba, Jordan

Radon concentrations were measured along six profiles crossing three morphotectonic features of the Dead Sea transform fault in Wadi Araba. Two profiles of detectors were placed across a fault scarp, a sag pond and a pressure ridge formed along the active Wadi Araba strike-slip fault. The maximum radon peak was measured in the pressure ridges (1.8±0.07)kBqm-3. This high concentration may be due to the up squeezing and heterogeneous fracturing of the Cretaceous and the Pleistocene Lisan beds beneath the pressure ridges. The minimum radon readings were measured in the sag pond floor (0.4±0.06)kBqm-3, the fractures are concentrated at the pond borders and not in the pond floor. The sag ponds are filled with fine sediments, which decreases the porosity and hence the upward radon migration. The fault scarp has intermediate radon radiation, with concentration values ranging between 1.1 and 1.2kBqm-3.