Coupling Near-surface Geophysics with Three-Dimensional Geological Model Building for Environmental Investigations

Investigating the subsurface at scales relevant to environmental remedial investigations can be complicated in areas that have been repeatedly glaciated or complicated by the presence discontinuous frozen ground and fractured bedrock. Ground water flow and contaminant migration pathways are very hard to infer in such heterogeneous aquifers characterized by a complex system of juxtaposed hydrogeological facies. Our investigations have merged using near-surface geophysical surveys with complex three-dimensional geological modeling using EarthVision at various sites in Alaska to assist with better delineating possible groundwater and potential contaminant migration pathways to assist with remedial investigations. These modeling efforts provide a three-dimensional framework to assist with remediation decision-making. Site characterization data were acquired from near-surface seismic refraction tomography, DC resistivity surveys, ground penetrating radar profiles, deep borehole drilling, hydrological modeling, and water quality observations. These data are synthesized to develop a conceptual model of local geology in the context of regional record; the conceptual model is then used as the basis to develop a three-dimensional model of subsurface conditions by modeling the data using EarthVision software.