VLF-EM surveys provide analytical assessments of anomalous subsurface conductive bodies. It is considered one of the simplest EM methods used to efficiently identify near-surface conductors. The VLF-EM method utilizes the principles of electromagnetic induction to image and qualitatively assess electrically conductive subsurface objects and features. Such structures are located around the globe and used by the military for navigation and communication. The very low frequency electromagnetic (VLF-EM) method is a passive electromagnetic (EM) method that exploits the EM radiation emitted by preexisting radio transmitters.
