T&A Survey is currently carrying out a geophysical soil survey on an industrial site for a large engineering firm. The aim is to map the specific electrical resistance in the soil. In this study, we chose to use electrical resistance measurements (ERT).
Electrical resistance measurements
Geoelectrical surveys are performed to measure the electrical resistance of the subsurface from ground level. The resistance of the soil depends on various geological factors such as soil composition, porosity and water content.
The figure below shows the setup of the ERT measurements. The two outer electrodes send a current into the ground. The two inner electrodes measure the resulting potential difference.