Developing a near surface electrical resistivity model of Great Britain

A model of the near surface electrical resistivity of Great Britain is presented. The first geological unit beneath the base of soil layer is attributed with electrical resistivity. Geotechnical data are used to derive modeled resistivity distributions for each of the lithostratigraphic units described in the near surface geological model of Great Britain. Resistivities are calculated using an effective medium methodology and these values are tested against electrical resistivity sounding data and apparent resistivity estimates from the airborne electromagnetic surveys. The central moments of the statistical distributions are coupled to the geological map and the resulting resistivity distribution shows a general increase in resistivity from SE England to NW Scotland. This pattern reflects the age of the bedrock geology of Great Britain. The methodology described in this paper can be applied to other regions where suitable geotechnical information and geological mapping is available.