Geophysical Assessment of Salt Sinkholes Hazard along the Dead Sea Shore in Israel and Jordan

Abstract

An integrated geophysical approach is presented for analyzing processes of subsurface salt dissolution and associated sinkhole hazard in the Dead Sea region. The implemented methods include Seismic Refraction (SRFR), Transient Electromagnetic method (TEM), Electric Resistivity Tomography (ERT), and Ground Penetrating Radar (GPR). A combination of these methods allows delineating salt layer boundaries, estimating its porosity distribution, finding cavities within the salt layer, and identifying deformations in the overlying sediments. This approach is shown to be useful for anticipating the occurrence of specific sinkholes, as demonstrated on both shores of the Dead Sea basin. These sinkholes are observed at present mainly along the edge of a salt layer deposited during the latest Pleistocene, when the Lake Lisan receded later become the Dead Sea. This salt layer is dissolved by aggressive water flowing from adjacent and underlying aquifers, which drain to the Dead Sea. This process is accelerating today due to the rapid fall of the Dead Sea level during the last thirty years caused basically by anthropogenic use of its water.