Electromagnetic surveys are conducted using frequency-domain or transient electromagnetic techniques. In the near-surface (15 to 20 feet deep), frequency-domain electromagnetic methods can be applied to:
Detecting and mapping lateral variations in the lithology of soils and rocks
Finding and mapping contaminant plumes
Locating buried metallic objects, such as tanks, drums, pipes, and utilities
At near- to mid-surface depths of 20 to 3,000 feet, transient electromagnetic methods can be applied to:
Delineating depth and thickness of geologic and hydrologic units
Detecting the water table and water quality, including salinity
