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Resistivity Mapping With Airborne Electromagnetic Induction Apparatus
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 3rd EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, Mar 1990, cp-212-00001
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Abstract
The benefits of mapping the electrical conductivity of the earth's surficial layers in support of various engineering, geological and hydrological investigations are amply demonstrated in the scientific record that spans the last sixty years. Until quite recently all such surveys were done directly on the surface with the classical four electrode dc resistivity method. Although<br>the early practitioners of this technique (Lee, 1936) had to contend with poor instrumentation, lack of reliable data interpretation aids, and strong competition from water diviners, much progress was made and resistivity measurements are now used on a routine basis in all parts of the world. Most of the investigations on record were carried out with the aim of outlining <br>occurrences of groundwater and of determining its quality. Next we note engineering applications based on the definition of the lithology and thickness of soil cover which must be known for the proper planning of dam sites, road locations, pipeline routes and mining operations. All of these applications rely on the successful differentiation and mapping of surficial deposits. The <br>measurements are based on the fundamental precept that different geological formations have characteristic values of electrical conductivity.