f FIELD VALIDATION OF THE LONG-ELECTRODE ELECTRICAL RESISTIVITY METHOD FOR SUBSURFACE CHARACTERIZATION AND MONITORING

Industrialized areas pose a challenge to the traditional paradigm for electrical resistivity characterization. Although these areas are a major source of contamination, liabilities such as limited access for electrode placement and the degree of near surface metallic infrastructure degrade the ability to successfully image the full extent of the target. Potential methods to overcome these liabilities include 1) interpreting underlying features knowing that the infrastructure exists only in small portions of the data, 2) post processing and filtering the resistivity data to remove the effects of infrastructure indirectly, and 3) taking advantage of the site’s infrastructure by incorporating the buried metal as electrodes. The latter has been shown to be a promising method for characterization and monitoring of underground storage tank facilities (or tank farms) on the Department of Energy’s Hanford Nuclear Reservation. At the Hanford site, the steel-cased monitoring wells that surround the storage tanks, originally installed for borehole logging, are being used as electrodes to track historical leaks. This method has been referred to as long electrode electrical resistivity tomography (LE-ERT).