Characterization of a Buried Quarry by Historical Analysis of Satellite Images Integrated with Electrical Resistivity Tomography, East Cairo area, Egypt

Abstract

East Cairo is characterized by abundant quarries that have been used as land ll sites for solid waste.These sites have become part of the urban sprawl of New Cairo, and their detection became di cult from the ground surface. In this study, analysis of multi-temporal high-resolution satellite images and electrical resistivity tomography (ERT) data were used to detect and delineate a buried land ll site located near the Ring Road, East Cairo, Egypt. Analysis of changes detected on the satellite images revealed that the study site was a WNW-oriented Quarry until 2005 and then randomly lled with heterogeneous solid materials.ERT survey was planned based on the result of change detection. On the plan view, the ERT measurements have outlined the electrically conductive zones which are occupied by lling material and distinguished them from the resistive zones that symbolize the natural soil areas. By assimilation of the satellite images and the ERT results, two distinguished geoelectrical units could be perceived; Unit-1 (the upper unit) is characterized by low to moderate resistivity values being the solid waste materials, while Unit-2 (the lower unit) is characterized by high resistivity values that characterize the original soil (bedrock). The closely spaced grid of ERT pro les and the detailed topographic map helped in mapping and delineating the contact between the bedrock and the lling materials. Several parameters could be addressed and were used for characterizing the unit of interest (Unit 1) including ground surface elevation, depth of the lower boundary of Unit-1, and thickness variation of this unit across the investigated site.