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Electromagnetic Ground Conductivity

In electromagnetic (EM) surveying, the electrical conductivity of the ground is measured as a function of depth and/or horizontal distance. Different rocks, buried structures and objects exhibit different values of electrical conductivity. Mapping variations in electrical conductivity can identify anomalous areas worthy of further geophysical or intrusive investigation.

Due to the rapid data collection methodologies utilising GPS positioning systems, the Electromagnetic Mapping method is often used as a reconnaissance style survey to rapidly characterise sites prior to intrusive investigations. With most site investigations, EM mapping can provide an overview of contamination concentrations, thickness of overburden across a site etc, and hence can be used to target any future sampling and testing strategies.

EM Applications

  • Locating dissolution features and subsurface voids
  • Locating underground storage tanks and drums
  • Mapping buried foundations
  • Mapping buried utilities
  • Locating the boundaries of landfills
  • Mapping leachate migration
  • Mapping and monitoring groundwater pollution
  • Mapping saline intrusions
  • Determination of layer thickness and conductivities