The purpose of this survey is to determine the probable burial locations of unmarked graves, using Ground-Penetrating Radar (GPR). GPR is a geophysical prospecting technology that transmits pulsed radio waves into the subsurface. Reflected radio waves from differences in dielectric permittivity build a map of the subsurface. Mapping these changes in relative dielectric permittivity and looking at depth slices of data in a cross-section (X-Y Plane) show differences in conductivity. This conductivity can be used to determine relative differences in densities and properties in the subsurface, thus potentially identifying burial locations.
Using a three-wheel cart, mounted with an GSSI SIR 4000 and a 400 MHz antenna, 2D scans and 3D scans were taken. To determine probable areas of unmarked graves preliminary 2D scans were taken and areas of interest were flagged. After determining a few areas of interest, a grid was built to include all areas of interest while maintaining a manageable area based on site conditions. The determined area included a 40-foot by 25-foot rectangle of 1000 square foot area. In this site, three locations of interest were included. Grid spacing was determined to provide the best data at 1-foot intervals allowing for the most data to be collected and presented. Radan 7, a post processing tool for geophysical investigations, was then used to combine the X and Y files into a 3-dimensional file. An IIR filter, background removal filter, and migration were applied to the data. Gain and Color X Forms were then chosen to best present the data.