US GPR Suitability Map

Published on the USDA NRCS website (higher resolution maps for individual states can also be found here):

Ground-penetrating radar (GPR) is a geophysical method that is often mentioned in news commentaries for its use in locating unmarked graves, clandestine burials and tunnels, terrorism and military hazards, and disaster victims. However, the effectiveness of GPR in these activities is highly site-specific and soil dependent. A common concern of GPR service providers is whether or not GPR will be able to achieve the desired depth of penetration in the soils of an assignment area. In many soils, high rates of signal attenuation severely restrict penetration depths and limit the suitability of GPR for a large number of applications. Knowledge of the probable penetration depth and relative suitability of soils can help service providers assess the appropriateness of using GPR and the likelihood of achieving acceptable results. Soil attribute data contained in the State Soil Geographic (STATSGO) and the Soil Survey Geographic (SSURGO) databases have been used to develop thematic maps showing, at different scales and levels of resolution, the relative suitability of soils for many GPR applications.

US GPR Suitability Map