Determining geophysical responses from graves

Graveyards and cemeteries around the world are being increasingly designated as full. There is a growing requirement to identify burial spaces or to exhume and then re-inter burials if necessary. Near-surface geophysical methods offer a potentially non-invasive target detection solution; however there has been lack of research to identify optimal detection methods using such geophysical techniques. This study has collected multi-frequency (225 MHz – 900 MHz) ground penetrating radar, electrical resistivity and magnetic susceptibility surface data over known burial sites with different burial ages and UK church graveyards. Results indicate that progressively older burials are more difficult to detect but successful grave detection is complicated by soil type. Different geophysical techniques were optimal in the three sites surveyed, which therefore suggests a multi-technique approach should be utilised by survey practitioners. Graveyard geophysical targets included the grave soil present above earth-cut graves, the grave contents themselves, brick lining (if present) and grave soil leachate plumes that are all geophysically detectable from background levels. Grave markers were also identified as not always being located where the burials were positioned. This study clearly demonstrates the value of these techniques in grave detection and inform search teams detecting clandestine burials