A New Method of Subsurface Imaging—The LASI High Frequency Ellipticity System: Part 3. System Tests and Field Surveys

Abstract

This paper is Part 3 of a three‐part series. In Part 1, we described the design and development of a new high‐frequency (HF) ellipticity system and in Part 2, we described the data processing and interpretation for this system. In this part, we provide five case histories showing the use of the system. The first case history involved tests over a “perfectly conducting earth,” which was used for verification of the system response. The test was made over an 8 m by 15 m aluminum sheet, which provided a good approximation to a perfectly conducting earth. Since the electrical properties of a perfectly conducting earth are precisely known, we were able to accurately calculate the expected electromagnetic response over this “earth.” We were then able to use these measurements to verify the system response and demonstrate that we can produce field data that accurately matches model results. The second test was over a homogeneous earth, which was used for interpretation of and The soil electrical properties at this site had been previously characterized with well logs and with laboratory electrical‐property measurements. We were therefore able to demonstrate the system's ability to extract information about and from our field data. The third test used large‐scale physical modeling. We measured electromagnetic responses over barrels, pipes, and metal sheets, which closely matched theoretical responses. The next two case histories were demonstration surveys at a Department of Energy (DOE) Site. The first was at a site known as the acid pit in the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). This survey successfully mapped the subsurface extent of an acid plume containing various hazardous materials. The second demonstration was at a location known as the Cold Test Pit (CTP) at INEL. This pit was designed to simulate hazardous waste of the type that is buried at many DOE sites. This survey effectively mapped the distribution of the various waste forms.