What is resistivity imaging?

Resistivity imaging, also known as electrical resistivity tomography (ERT), is a geophysical technique used to determine the subsurface resistivity distribution. The principle is based on the fact that different materials have different electrical resistivities. The resistivity of a material describes its ability to resist the flow of electric current.

In resistivity imaging, an array of electrodes is placed on the ground surface and a small current is injected into the ground through two electrodes. The resulting potential difference is measured between other pairs of electrodes. By analyzing the distribution of electrical potentials, it is possible to infer the resistivity distribution of the subsurface. High-resistivity materials, such as dry rocks or minerals, will produce high potentials, while low-resistivity materials, such as water-saturated soils, will produce low potentials.