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Geophysical surveys, which use geoelectrical methods base on the variation of electrical parameters of the soil. To understand the phenomena in ground-rock medium, in which electric current flows, it must be realized that such substrate resists while electric current flows through it. According to Ohm`s Law, resistance R is directly proportional to applied voltage U and inversely proportional to current intensity I. Basic parameter which is calculated using geoelectrical methods is electrical resistivity of the soil. Therefore, geoelectrical methods are equated with electrical resistivity methods. Resistivity is the property of material and on its basis we are able to characterize the ground below the surface.

Geophysical studies using resistivity method are based on the determination of electrical resistance changes of the ground. These changes are natural (geological) or anthropogenic, and have a resistance different from the surrounding ground.

Resistivity soundings is basic resistivity technique. This technique bases on the relegation of current electrodes from the potential electrodes in subsequent step to increase the depth of investigation. The point for which the measurement is made is in the middle between the potential electrodes.

Soil testing by electrical profiling method the same arrays as for sounding (Schlumberger`s, Wenner`s etc.) are used. Electrical profiling is a basic resistivity survey technique about moving the whole array along the profile with unchanged geometry. The assumption of electrical profiling is the constant depth of investigation.

Electrical resistivity tomography ERT is also known as resistivity imaging. This method is combination of electrical sounding and profiling because surveys are done along the profile and with increasing depth of investigation.