Print this pageUsing Normalized Residual Polarization (NRP) Analysis of Ground Penetrating Radar Data to Detect Jet Propellant in Soils
Jordan, Thomas E. 1, Baker, Gregory S. 1, Henn, Keith 2, and Messier, Jean-Pierre 3
1University at Buffalo Department of Geology
2Tetra Tech NUS
3United States Coast Guard Support Center
The success of using amplitude variation with offset (AVO) analysis of seismic reflection data for locating petroleum resources has prompted researchers to examine this application for delineating contamination in the near surface. The analogies of elastic (seismic) to electromagnetic (EM) wave propagation and energy partitioning at interfaces has prompted interest in pursuing AVO analysis methods for delineating near surface targets with ground penetrating radar (GPR). This research was initiated to determine the applicability of AVO/GPR techniques for delineation of jet propellant-4 (JP-4) and jet propellant-5 (JP-5), which are both a light non-aqueous phase liquid (LNAPL). This paper presents the results from a case study where the normalized residual polarization (NRP) method was developed for analyzing AVO/GPR data.
Ground penetrating radar data were collected at a former fuel farm (FFF) where a JP-4 and JP-5 release occurred. The FFF site is located at the United States Coast Guard (USCG) Support Center facility located in Elizabeth City, North Carolina. The near surface geology of the FFF consists of clayey silt with varying amounts of clay and interspersed sand lenses overlying fairly uniform fine-grained sand.
Results of the NRP AVO analysis of the GPR data indicate that identifiable anomalous responses are associated with zones of free phase LNAPL in the soils. Furthermore, it appears that the characteristics of the anomalous responses may allow the user to determine if the anomalous response is due to NAPL or due to other subsurface features such as stratigraphic changes.