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.

Applications:

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

Advantages:

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