Seismic Applications For Detecting Preferential Pathways At Tinker Air Force Base, Oklahoma

Tinker Air Force Base has been in operation since 1942, and serves as an international<br>repair depot for a variety of aircraft, weapons and engines. Past disposal practices of various<br>waste materials have caused contaminated soil and groundwater at many sites on the Base.<br>As part of the DNAPL plume delineation and remediation effort at Tinker Air Force<br>Base, various types of geophysical methods have been utilized. One that has proven successful<br>at Tinker is seismic. Two-dimensional seismic data has been acquired at three sites on Base.<br>Interpretation results are being used to help identify preferential pathways, such as subsurface<br>sand channels, low porosity zones and ‘holes’ located in the confining layer, that might<br>contribute to current plume configurations and locations. Once these pathways are identified,<br>their locations will be used to optimize future remediation systems.<br>The first 2D survey was successful in identifying subsurface sand channeling and will be<br>used to help locate future groundwater extraction wells for an existing pump and treat system.<br>At the second site, 2D seismic data is being used to identify pathways that are creating a plume<br>configuration which is oriented perpendicular to the groundwater flow direction. The third 2D<br>survey is being used to identify ‘holes’ in the confining layer, which are allowing contamination<br>to migrate vertically. In all cases, the seismic data, combined with monitor well data, is used to<br>identify ‘lows’ in the confining layer that might cause DNAPLs to pool.