The seismic velocities of Dead Sea salt applied to the sinkhole problem

The geophysical properties of Dead Sea salt layers located under the groundwater table were investigated in association with the sinkhole formation problem. The salt velocity criterion of Vpmin = 2900 m/s (within the Dead Sea graben area) is accepted as the statistically substantiated lower limit of the compressional wave velocity (Vp) for the central and southern parts of the Dead Sea western shore. Seismic refraction data from the Ein Gedi and Nahal Hever south areas are reinterpreted using the General Reciprocal Method (GRM). The velocity mapping shows the compact salt layer boundary at the Ein Gedi site and salt dissolution zones within the compact salt area at the Nahal Hever site as confirmed in situ by drilling. Comparison of the salt boundary with the sinkhole arrangement line permits us to assume that the “salt edge dissolution” model with local features is responsible for sinkhole formation at the Ein Gedi site.