Geoelectrics

Geoelectric investigations are non-invasive investigations through which the subsurface is studied by injecting electric current into the ground. These investigations have a range of applications: obtaining the soil stratigraphy, performing geo-archaeological investigations, identifying aquifers, identifying the presence of contaminants within aquifers.

Each type of soil shows physical variations that distinguish it from others, for example: grain-size distribution, void ratio, water content. When the soil is crossed by an electric current, it behaves like a resistance, with a specific resistivity given by its physical characteristics. By knowing the voltage induced in the soil and by performing many measurements, it is possible to discretise soil types and their lateral and vertical variations.

Tecnostudio performs electrical resistivity tomography (ERT). ERT involves driving multiple electrodes into the ground along a line, spaced at fixed intervals. By alternately activating the electrodes, an apparent resistivity section is obtained (a sort of "raw" section of the area being investigated).

Through dedicated software, the data collected is reviewed and processed in order to obtain a stratigraphic section of the soil that shows the distribution of lithologies in the subsurface.