Some Laboratory Electromagnetic Studies over Resistive Bodies in a Conductive Environment

Abstract

Scale model experiments over resistive bodies in a conductive medium have been carried out to study the application of electromagnetic methods in prospecting for groundwater and construction materials. Also, some computational results have been reviewed. Freshwater buried stream valleys, freshwater lenses in sand dunes and in sand and gravel bodies are often embedded in clays or surrounded by layers containing saline water. The constitution of these bodies is geoelectrically equivalent to the presence of a nonconducting body in a conducting medium. The electromagnetic response of a resistive body in conducting homogeneous and heterogeneous half-spaces has been studied for the case of a horizontal coil prospecting system. The EM anomalies obtained are caused by(il variations in the current-path geometry in the host medium (ii) changes in the magnitude of the induced currents, and (iii) interaction between the conducting flanks, when a resistive body is immersed in a conducting medium. A field example is shown of the application of horizontal-coil EM method in delineating a frosh-water burried stream in clays.