Using 3D Seismic Surveys to Identify DNAPL Migration Pathways
Launch Complex 34, Cape Canaveral Air Station, Florida

In cooperation with the Interagency DNAPL Consortium, and its mission to develop new innovative technologies for DNAPL (dense nonaqueous phase liquids ) detection and characterization, RRI performed a high-resolution 3D seismic reflection pilot survey at Launch Complex 34 (LC34), Kennedy Space Center, Florida.

The 3D survey addressed an area of approximately 55,200 square feet on the surface of the site.  The survey area included a portion of the engineering support building at LC34 (pictured), and because of the non-invasive nature of the seismic method, data were collected both inside the building and on the adjacent asphalt-covered lots.  The seismic survey was designed to produce a continuous 3D subsurface image to a depth of 480 ft, and with 1-5 ft resolution in the area of interest.

A focus of the seismic survey was to map a suspected clay confining layer below the DNAPL source area.  Interpretation of 3D seismic data revealed that the clay layer was fractured in many locations and discontinuous.    It was determined, based on the seismic work, that the clay layer should more properly be classified as a semi-confining layer.  Subsequent drilling confirmed the presence of DNAPL below the clay layer.  The confirmatory drilling is detailed in a paper presented at the Third International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Monterey,CA; May 2002), which can be download here.