Twenty Years Of Progress In Electromagnetic Exploration For Near-Surface Geophysics

Progress in electromagnetic exploration for engineering and environmental investigations is characterized by development and adaptation in practice of three technologies. New metods now extensively employed are, terrain conductivity meters for shallow electrical conductivity profiling, time domain electromagnetic soundings in the dept range from about 30 m to 1,500 m and time domain electromagnetic profiling for detecting small buried metal objects. The relatively rapid acceptance of these technologies in engineering practice appears the result of merging of several factors, such as the existence of a solid theoretical foundation, instrument manufacturers who developed instrumentation specific for needs in engineering and environmental studies, and professionals willing to introduce new technologies in practice.