Coupling of field investigations and remote sensing data for karst hazards in Egypt: case study around the Sohag City

Abstract

Karst rocks cover a wide area of Egypt. These rocks include soluble sediments such as carbonate rock formations, evaporites, and sabkha deposits that are characterized by karstification features. Karst features could affect many current and developing projects (urban areas and infrastructure). The areas covered by the rocks susceptible to karstification need detailed studies to examine the presence of karst features and/or sinkholes. The current work provides a detailed evaluation of the karst and/or sinkhole hazards around the city of Sohag, Egypt. This research is rarely done in Egypt, using field investigation and remote sensing application to determine the main karstic rock formations and the distribution of the most problematic sinkhole areas. In this work, different types of the subsidence mechanisms were investigated. Our results indicated that field investigations help in finding different features related to karstification including small-scale versus large-scale features and empty caves versus filled caves. In addition, remote sensing techniques succeeded in predicting and locating the sinkhole areas, and those determinations were verified in the field. Finally, fundamental considerations are discussed to better evaluate and manage the hazard of karst and/or sinkholes.