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2284 NW Thurman St.
Portland, Oregon, 97210
Voice: (503) 227-7659
Fax: (503) 227-1074

Geophysics - Vibration & Noise - Rock Mechanics

Providing Quality Geophysical Consulting Services since 1984

VLF Method

The Very Low Frequency (VLF) geophysical exploration method is useful for locating high conductivity structures such as water-filled fractures, certain orebodies, clay-filled sinkholes, metallic pipes, buried waste, and electrical cables.  VLF signals are generated at several locations around the world.  They are primarily used for military communications purposes. Exploration VLF equipment measures the magnetic components of the electromagnetic field generated by the VLF radio broadcast.   Conductive structures in the ground locally affect the direction and strength of the field generated by the radio signal.

 The VLF technique is generally used for reconnaissance  mapping of faults, structure patterns, contaminants and mineral deposits.   Limitations of the method include interference from buried metal, power lines, transformers, fences and other electromagnetic disturbances.