Detection of Fractured Limestone Landslides Using Electrical Resistivity Tomography: A Case Study in the Mokattam Plateau, Egypt

Abstract

Landslides occurred in the Ain Moussa area, north of Mokattam, Egypt. The study aims to detect landslide causes in fractured limestone using electrical resistivity tomography. The result of the electrical resistivity tomography profiles showed that there are two main layers: the first is a high-geoelectrical resistivity layer of fractured limestone covered in some places by backfill sediments, and the second is a low-geoelectrical resistivity layer of shale below the limestone. In between the two layers is a zone that is holding the weight of water leaking from the surface; it has a medium resistivity value. These results were compared with available satellite images. Based on the results, it was found that there is a layer of fractured limestone on the surface. The top part of it is dry, but the bottom part has water leaking from the surface, which has the biggest effect on landslides. The shale layer's surface is irregular, as it was discovered that the most influential part is the low part of the shale's surface, as it contains a high-water content and thus is more affected, and it is where the landslide occurred. It is possible to identify the deepest points of the shale layer, on which the water leaking from the surface collects, along the plateau, as these places are more likely to cause landslides.