Ground-penetrating radar soil suitability map of the conterminous United States

The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical conductivity. Soils having high electrical conductivity rapidly attenuate radar energy, which restricts penetration depths and severely limits the effectiveness of GPR. Factors influencing the electrical conductivity of soils include the amount and type of salts in solution and the clay content. The Ground-Penetrating Radar Soil Suitability Map of the Conterminous United States is a thematic map showing the relative suitability of soils for GPR applications within comparatively large areas of the United States. This map is based on over twenty-five years of field observations made throughout the United States and soil attribute data contained in the State Soil Geographic (STATSGO) database. Attribute data used to determine the suitability of soils include taxonomic criteria, clay content, salinity, sodium absorption ratio, and calcium carbonate content. Based on additional testing, several GPR specific adjustments have been made. This paper describes these revisions and outlines the procedures used to develop the revised map. The revised map limits areas that are rated as being “Unsuited” for GPR to saline and sodic soils, reassesses calcareous and gypsiferous soils, and provides a mineralogy override for soils with low activity clays. This map can be used to assess the relative appropriateness of GPR for soil investigations within comparatively large areas of the conterminous United States.