ERT+IP surface geoelectrics

These completely noninvasive investigations provide fundamental information on the lithological nature of soils due to the sensitivity of electrical resistivity to physical parameters such as mineralogical composition, presence of fluids, temperature, porosity, and degree of cementation of the material. An extension of the ERT method is Induced Polarization (IP), a complementary technique that measures the apparent chargeability of soil. After DC injection, the decay of the electrical potential during the discharge phase is recorded, a parameter sensitive to the low-frequency capacitive properties of the materials. These properties are related to electrochemical polarization processes occurring at the interface between grains and fluids in the pores, often influenced by fluid chemistry, lithological variations.

Prospecting is conducted along linear profiles (2D) or on areally distributed grids (3D), by installing equidistant electrodes, connected by a multicore cable connected to a geosurveyor. Finally, taking repeated measurements over time (timelapse), especially in 3D configuration, is a powerful tool for dynamic monitoring.