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As part of a multiscale hydrogeophysical and modeling study, a pseudo three-dimensional (3-D) seismic survey was conducted over a contaminant plume at P area, Savannah River site (South Carolina), to enhance the existing geologic model by resolving uncertainties in the lithostratigraphic sequence. The geometry of the dissolved phase trichloroethylene plume, based on initial site characterization, appears to be confined to a narrow corridor within the Eocene sand overlying a clay unit approximately 25 m (82 ft) below land surface. Processing the seismic data as a 3-D data volume instead of a series of closely spaced two-dimensional lines allowed for better interpretation of the target horizons, the lower clay, and the sand above the clay. Calibrating the seismic data with existing borehole geophysical logs, core data as well as vertical seismic profiling (VSP) data allowed the seismic data to be inverted from two-way traveltime to depth, thereby facilitating full integration of the seismic data into a solid earth model that is the basic part of a site conceptual model. The outcome was the production of realistic horizon surface maps that show that two channel complexes are located on the section, which are not present in the conceptual model, and that the upper and middle clays are not laterally continuous as previously thought. The geometry of the primary channel has been transposed over the map view of the plume to investigate potential relationships between the shape of the plume and the presence of the channel.
Adrian Addison is a Ph.D. candidate in the Department of Geological Sciences at the University of South Carolina. He received his B.S. degree in geophysics from the University of Oklahoma and worked for 4 years as a geophysicist with the U.S. Geological Survey. His research interests are borehole and near-surface geophysics, environmental geology, and signal processing.
Michael Waddell completed his graduate studies at ESRI-USC in 1982 and remained at ESRI-USC until 1984 when he became a reservoir geologist in Houston working on petrographic investigations of hydrocarbon reservoirs worldwide. In 1986, he returned to ESRI-USC to start an environmental geophysics group and is presently its manager.
Camelia Knapp received her Ph.D. in geophysics from Cornell University and her B.S. and M.S. degrees in geophysical engineering from the University of Bucharest (Romania). She worked with the Romanian State Oil Company and the National Institute for Earth Physics. Currently at the University of South Carolina, her research interests include exploration and environmental geophysics, crustal-scale seismology, and gas hydrates.
Duke Brantley is an M.S. degree candidate in the Department of Geological Sciences at the University of South Carolina. He received his M.S. degree in earth and environmental resources management from the University of South Carolina in 2006. He provides field and analytical support for geophysical and dewatering studies for the Earth Sciences and Resources Institute at the University of South Carolina.
John Shafer earned his Ph.D. in civil engineering from Colorado State University, his M.S. degree in resource development from Michigan State University, and his B.S. degree in earth science from Penn State University. His research focus includes integrated site characterization, coupled simulation-optimization approaches to solving groundwater problems, and groundwater susceptibility and contamination potential analysis.