EM (electromagnetic) mapping consists of measuring the electromagnetic resistivity of the physical components of the earth. VLF stations provide quantitative information about the subsurface, which allows us to map structures and bodies whose physical properties are related to electromagnetism; Igneous rocks, some mineralized bodies, faults, fractures and water bodies.
The resistivity data obtained by the VLF methodology are represented as lateral variations of the electrical conductivity in the subsoil at one or more frequencies. However, thanks to advances and the development of data inversion algorithms, it is possible to obtain vertical profiles of electrical resistivity at depths between 30 and 75 meters, although for environments with resistive materials it is possible to reach depths greater than 100 meters.
The global distribution of the transmitters, the versatility and the ability of the sensor to operate over a wide temperature range, allow electrical resistivity mapping to be carried out practically anywhere in the world.
This type of survey is ideal for the characterization of conductive bodies such as ferromagnesian minerals, delimitation of dumps or landfills, search for water bodies, karst studies, among others.