Dynamics of sinkhole and uvala development on the eastern shore of the Dead Sea, 1980-2022

The Dead Sea is a hypersaline terminal lake whose level has been declining due to anthropogenic stresses since the 1960s. At its eastern shore, near Ghor-Al-Haditha in Jordan, over 1200 collapse sinkholes have been mapped roughly parallel to the shoreline from the 1980s until 2017. This mapping also documented five larger karstic depressions (uvalas), that formed in close spatial-temporal association with the sinkholes, and demonstrated that sinkhole and uvala formation during this period has migrated laterally, both in the direction of shoreline retreat (from east to west) and parallel with the shoreline from south to north.

Here, we use new, high-resolution optical satellite imagery from the Pleiades and PNEO satellites, to show that over 500 new sinkholes have formed between 2018-2022. Furthermore, three new uvalas have developed to the north in accordance with the appearance of the sinkholes. Our study indicates quantitatively that the coalescence of sinkholes to form larger compound sinkholes is a subsequent stage of uvala development. New mapping confirms a previously established link between sinkhole size distribution and the mechanical properties of the sedimentary materials in which they form, with holes formed in salt-dominated morphologies being smaller in diameter than those in alluvium and lacustrine mudflats. Initial comparison to local meteorological records has shown that a temporal link between periods of high rainfall and enhanced sinkhole formation is not readily apparent at the resolution of the sinkhole mapping. Moreover, as previous studies had hypothesized, growth of the sinkhole population and the uvalas continues towards the north and is diminished to the south. Our results help to inform hazard monitoring and mitigation strategies at Ghor Al-Haditha: for example, presently growing areas of surface depressions are within 130 meters of a 700-meter-long stretch of the western main highway connecting the north and south of Jordan. Therefore, we suggest that infrastructure such as the highway continue to be monitored in light of the observed subsidence.