Resistivity Imaging seeing what lies beneath Resistivity imaging is a geophysical technique that allows a trained geophysicist to identify changes in subsurface conditions based on electrical resistance . Resistivity is an innovative and effective method to identify environmental and engineering features, such as confining clay layers, sand and gravel zones, landfill boundaries, contaminant plumes and preferential flow paths. To briefly explain how resistivity imaging works, an alternating current is applied across electrodes placed at known spacings on the soil surface. The potential drop of the current between the electrodes indicates whether the subsurface geology includes any resistance anomalies, indicating the likely presence of sand, gravel, clay layers, bedrock or water. A 2D or 3D image of the subsurface is produced.
Many people often think that soil or rock layers are found in flat even layers.
This is seldom the case. Frequently there are significant variations in the soil and rock layers. The image below was generated by resistivity imaging . Accurate analysis of subsurface conditions is critical for environmental and geotechnical investigations. Rapid field investigations for subsurface studies have benefited greatly by advances in portable geophysical techniques, such as resistivity imaging.