Microgravity Application for Detection of Underground Cavities in a Desert Karst Terrain

A number of sinkholes were detected in a residential area located close to the northeast coastal side of the Arabian Peninsula. The sinkholes occurred suddenly with different sizes and a maximum depth of 31 m. Comprehensive investigation studies were conducted for understanding the causes of the sinkhole occurrence and to recommend remedial measures. Microgravity survey method was used for geophysical investigation of the area to detect subsurface cavities. The validity of the microgravity survey was confirmed after applying a drilling program. After 15 years, another microgravity survey was conducted in selected locations of the same residential area for the purpose of verifying the current underground status and assessing its development. In this paper, the nature of the desert Karst terrain under study is described. The results of the two microgravity surveys are presented. The results confirmed the capability of the microgravity method to detect density anomalies and ground disturbances. The maps showed evolution of the anomalies in some locations within the studied area.