TIME-DOMAIN ELECTROMAGNETICS (TDEM)

(Geophysics) A high technology form of Dowsing (Dousing), or groundwater exploration, used to search for underground bodies of water (aquifers). The technique employs a grid pattern of electric wires placed on the surface of the ground. The wires are charged with a rapidly pulsating electric current and then the resultant electronic "echoes" are carefully analyzed. These data are then used to construct a three-dimensional computer model of the water-bearing potential of underground rock formations and sediment layers.