Electrical Resistivity Imaging (ERT)
Technical Explanation
Electrical Resistivity Tomography (ERT) injects current into the ground through an array of electrodes and measures the resulting voltage differences to image subsurface resistivity. The output is a cross-sectional model of the subsurface, revealing zones of high or low resistivity correlated with materials (e.g. rock vs. saturated soil). It’s a geophysical technique well-suited for mapping depth to bedrock, groundwater, voids, etc.
Main requirements
Required when a detailed underground profile is needed (e.g. for foundation design or environmental investigations). Needs a linear area to lay out cables and multiple electrodes across the survey line. Best applied in areas where ground access is available and provides 2D/3D images up to tens of meters deep.