Unlike electromagnetic conductivity mapping, which actively generates electromagnetic fields in the subsurface, a magnetometer measures subtle variations in the earth’s magnetic field passively, without imposing an artificial field.
Magnetometers are sensitive to two types of magnetic fields: induced and remnant. Induced fields are additional magnetic fields induced in metallic objects by the earth’s magnetic field. In contrast, remnant magnetic fields are due to magnetic minerals found in certain types of bedrock and soils. Thus, by detecting minute variations in the earth’s magnetic field caused by the addition of one or both of aforementioned magnetic fields, magnetometers can be used to detect metal objects as well as variations in soil and rock type.
Mundell & Associates uses magnetic methods to locate abandoned cultural resource areas, as well as to locate buried metal objects.
Magnetic Method Applications
- Unexploded Ordnance (UXO) mapping
- Locating Underground Storage Tanks (UST) and Buried Drums
- Locating Buried Debris and Landfills
- Mineral Exploration