Abstract: The geotechnical investigations in the karst terrains require not only to determine the variation the karstic rock surface, but also to real the development of the rock pinnacles, rock cavities in the rock mass as wells soil cavities at the soilbedrock interface. Due to the random occurrence of these adverse geological features, the drilling and rock coring cost will be excessively high, especially, if the drilling operation is under water. This paper presents the underwater highdensity resistivity method as a compensate method for the geotechnical investigations in the karst terrain.  

Key words: Underwater High Density Resistivity Method, Karst Terrain, Resistivity Properties, Reverse Analysis