Basalt is a common constituent in the subsurface throughout much of the Pacific Northwest. As such, the physical properties of basalt are relevant to engineering and hydrogeology in the region. The physical properties of basalt can change dramatically within a single flow and may be associated with changes in intraflow structure. The purpose of this thesis was to make geophysical measurements of a basalt flow and interpret them in terms of available geologic information. It is hoped that these results will be of value in future research to characterize basalt intraflow structures, such as efforts to remotely determine fracture densities and infilling materials.