In this section we look at Direct Current (DC) resistivity surveys. The physical property of for DC surveys is electrical conductivity \(\sigma\) (Siemens/meter) (or if you prefer its inverse, resistivity \(\rho\) (Ohm * meter)). For these surveys, the source is current injected into the ground, and the receivers measure the strength of the current and voltage differences.
DC resistivity is widely used for mining exploration, particularly for porphyry deposit, in geotechnics to find cavities in the subsurface or in environment to determine possible pollution leakage.
Some key areas to pay attention to with DC surveys are the various configurations (dipole-dipole, pole-dipole, gradient array, Schumberger and Wenner soundings), each of which delivers a particular focus on different subsurface information.