Electrical resistivity measures the bulk electrical resistance of the subsurface by inducing a current between two electrodes implanted in the subsurface. Electrical resistivity is used by SAIC to characterize subsurface stratigraphy, water table depth, conductive plumes, and buried wastes. 
With advances in technology, data collection and inversion methods have been advanced to the point that electrical resistivity is sometimes referred to as Electrical Imaging.