Time-Domain Electromagnetic (TDEM)

Transient electromagnetics, (also time-domain electromagnetics/TDEM), is a geophysical exploration technique in which electric and magnetic fields are induced by transient pulses of electric current and the subsequent decay response measured. TEM/TDEM methods are generally able to determine subsurface electrical properties, but are also sensitive to subsurface magnetic properties in applications like UXO detection and characterization. TEM/TDEM surveys area very common surface EM technique for mineral exploration, groundwater exploration, and for environmental mapping, used throughout the world in both onshore and offshore applications. It can also be used in finding voids & solution features in soil and rock, locating abandoned mineshafts, crown holes & subsidence features, identifying bedrock discontinuities & mineralized veining, defining former landfill sites & associated leachate plumes, detecting buried UST’s & dumped chemical waste drums, and mapping soil types and land drainage systems. However, this method shares the same imitation factors of ERT method.