LINEAR E-SCAN: A Reconnaissance Resistivity Mapping System that Evaluates its Own Anomalies En Route

Abstract

Single line resistivity traversing is commonly used in geothermal exploration, particularly in rough terrain, but also as a first pass test of more accessible prospective ground. Terrain restrictions often prevent the acquisition of the additional data needed to evaluate a single line anomaly, which could be reacting to geothermal activity directly below, to the side, or even as far away as several miles, if the anomaly is caused by intercepted outflow plume. The initial use of an automated multiple electrode potential mapping traverse system: increase the effective depth of penetration and the width of the sampled survey route by three to six fold, thereby increasing the opportunity to detect anomalies, and provides for immediate development (in any terrain conditions) of the one or more perpendicular survey lines needed to evaluate a single line transverse anomaly. Any potentially important anomaly can therefore be mapped fully, within 4 to 10 days, so that the optimum drill positioning or other follow up testing can be selected. An anomaly explained by non economic causes is rejected, perhaps after 1 or 2 days of testing. Once the anomaly is fully defined and classified, the survey traverse resumes.