Very Low Frequency (VLF)

VLF surveys utilize Very Low Frequency radio communication signals (ranging between 15 to 30 kHz) generated by military transmitters to determine electrical properties of near-surface soils and shallow bedrock. Excel operates EM16 VLF units that measure the in-phase and quadrature components of secondary electromagnetic fields created by eddy currents induced in conductive geologic units and structures. Depth of investigation varies between 4 to 60 meters depending on the soil's conductive properties.


  • Mapping fault zones
  • Mapping zones of conductive mineralization
  • Mapping contaminants


  • Low-cost
  • Lightweight and easily portable
  • Non-intrusive
  • Easy to operate
  • Environmentally friendly