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9088208 
Journal Article 
Fault and fracture system delineation of a bedrock aquifer 
Truskowski, M; Warner, J; Clark, J; Tisoncik, D 
2004 
Society of Exploration Geophysicists 
SEG Technical Program Expanded Abstracts 
23 
1393-1396 
English 
The site for this project is an active aircraft maintenance facility in Northern California. Chlorinated solvents were released into the ground between 35 and 50 years ago in the course of jet engine overhaul. Solvents, predominantly 1,1-TCA, 1,1-DCE, and 1,1-DCA, have been detected at the site in concentrations ranging from dense nonaqueous phase liquids (DNAPL) to non-detect over a small distance. Dissolved concentrations have been detected at depths greater than 400 feet in an area with both human and ecological receptors. Drilling had determined that bedrock topography was complex and bedrock was highly fractured. The degree and distribution of the fracturing was identified within the boreholes through the use of optical and acoustic borehole televiewer logging. A high-resolution/high frequency vibroseis reflection seismic survey was conducted to identify faulting, bedrock topography, and bedrock fracture systems. Acquisition of the survey was made more challenging by the round-the-clock movement of large aircraft through the survey area. The survey identified a complex fault system, including three primary faults, each with a complicated set of antithetic faults. The locations of the primary faults corresponded to areas of increased fracture density, and hence fluid and contaminant flow. Using the seismic survey as a predictive tool allowed focused placement of monitoring wells to define the extent of the plume. Subsequent drilling has confirmed the predicted bedrock topography, fault positions, and extent of the contaminant plume. © 2004 Society of Exploration Geophysicists. 
SEG Technical Program Expanded Abstracts 2004