APPLICATION OF GROUND PENETRATING RADAR IN CLANDESTINE GRAVE SURVEYS

In recent years, ground penetrating radar (GPR) has gained acceptance in a variety of fields, including geology, engineering, and archaeology, as a non-invasive method for capturing high-resolution imagery of subsurface objects. High-frequency electromagnetic pulses are used to produce a two-dimensional radargram that allows interpretation of near-surface anomalies. Because the wave velocities change dramatically when encountering void spaces and disturbed soils, GPR is particularly suited for grave detection and inventory surveys of old cemeteries. Buried objects produce a reflection hyperbola (inverted U), bedrock contacts and soil density changes show up as planar reflectors, and void spaces manifest as a ringing reflection. Since many cemetery sites have crumbling headstones or older graves with unmarked locations, these geophysical indicators offer enormous potential in locating lost and clandestine graves without digging, excavation, or drilling. This research conducts a GPR grid survey in the Brookside-Rexford Cemetery in Rexford, Pennsylvania, where a suspected mass grave of infant mortalities from the 1918 influenza outbreak were reported interred without coffins. The survey was conducted using both 100 and 500 megahertz Mala antennas in three 50 x 50 foot grids, to compare and interpret imagery at various scales and resolutions. Data was processed using GPR-Slice, a comprehensive GPR imaging software that produces 2D and 3D images.