Electrical Resistivity Imaging

Electrical resistivity imaging measurements determine the average resistance of the soil materials in a given area by inducing a current into the ground between two electrodes and measuring voltage changes between two other electrodes. Using Ohms law and the measured voltage changes, currents and the distance between electrodes the average ground resistance can be calculated. These resistivity values can be associated with common overburden/soils and bedrock types/condition. For electrical resistivity horizontal profiling, the electrode spacing is kept constant and the array is moved across the survey area. Electrical resistivity imaging measurements in horizontal profiling are often repeated with several different electrode separations to identify lateral variations at more than one depth.