It is a method for subsurface investigation that allows us to characterize rocks on the basis of the electrical resistivity.

Resistivity represents a very important physical property as it depends on various factors such as water saturation and porosity; it is recorded through surface measurements.
Field acquisition is accomplished by electrode configurations that may vary depending on the objectives of the investigation. Classical methods provide the production of mono-dimension resistivity models (Vertical Electrical Soundings - SEV) or resistivity profiles, for an evaluation of lateral lithologic variations.

The integration of the above mentioned methodologies implies the acquisition of a considerable amount of "apparent" resistivity data, representing electrical properties variations along the profile.
The utilization of inversion software (tomography) allows us the production of resistivity sections able to accurately reproduce variations of this parameter in the subsurface.

Electric surveys are generally applied in hydrology studies, to verify the sealing properties of HDO liners in the waste sites, in archaeological surveys and in environmental studies.