Sub-Audio Magnetics (SAM) — a high resolution technique for simultaneously mapping electrical and magnetic properties1

A high definition technique has been developed for simultaneously mapping electrical and magnetic characteristics of the ground. Each of the parameters may be measured at sub-metre intervals while continuously traversing either on foot or in a vehicle. Electric current, typically in the frequency range of 5 Hz to 200 Hz is induced in the ground by either galvanic of electromagnetic means. An optically pumped total field magnetometer continuously measures the natural and synthetic field changes from DC to the highest transmitted frequency. Real-time spectral analysis of the magnetic field changes allows a suite of geophysical parameters to be derived. The geophysical measurements so obtained include, but are not limited to: ? Total Field, High Definition Magnetics (HDM). ? Total Field, Magnetometric Resistivity (TFMMR). ? Total Field, Magnetometric Induced Polarisation (TFMMIP). ? Total Field, Electromagnetics (TFEM). Because of its inherent cost-efficiency and superior spatial resolution, the SAM technique has the potential to significantly enhance geophysical mapping for mineral exploration, archaeological investigation and environmental studies of salinity, industrial waste and chemical contamination in soils.