Detection of Marked and Unmarked Burial Sites in Louisiana Using Ground Penetrating Radar

Ground penetrating radar has been used in both north and south Louisiana, to locate marked and unmarked graves. Burials in Oak Ridge, Louisiana, which is in the northern part of the state, were in a church cemetery. Dates of burial ranged from the late 1800s to the present. The survey was conducted to determine the location of empty plots within the cemetery that could be used for future burials and to locate any unmarked burials. Burials in St. Gabriel, Louisiana, which is in the southern portion of the state, consisted of three marked graves on private property. Date of burials occurred in the 1970s. This survey was performed to confirm that the headstones were correctly placed over the bodies. A large surface depression was observed near the presumed location of the graves. Information regarding the exact location of the bodies was not known and one or more bodies were possibly buried in the area beneath the observed large surface depression. A Sensors and Software SmartCart bistatic ground penetrating radar unit equipped with 200-megahertz antennas with 0.5 meters of separation was used at both locations. Penetration was to a sufficient depth in order to determine locations of the burials at both sites. Longer wavelength antennas were available but not used because the 200-megahertz antennas adequately characterized the near subsurface. Sediments in the Oak Ridge site consisted of silty loams and a comparatively deeper depth of penetration was achieved. Sediment in the St. Gabriel site consisted of clays with less depth of penetration than in the Oak Ridge site. Previous studies by others in Baton Rouge, Louisiana just to the north of St. Gabriel have had poor results due to limited depth of penetration except in areas where the soil is covered by concrete or asphalt and thus remains dry year round. Both grave sites were surveyed while the soil was dry in order to ensure maximum depth of penetration. Data interpretation was completed on site during each survey using the display unit of the ground penetrating radar equipment. Further interpretation or manipulation of the data off site was deemed unnecessary for locating grave sites. On site interpretation of the data displayed on the radar unit proved to be fast and effective, as the majority of anomalies indicative of the presence of graves were observed and easily identified as strong, shallow reflectors. Ground penetrating radar can be used as a fast and effective device to evaluate potential burials and unmarked graves within Louisiana.