Four-month timeapse geophysical detection of simulated child burials.

Forensic burials are commonly used to dispose of evidence relating to crimes and can contain human remains, weapons, drugs, and other physical evidence. Currently, there is little literature on the ability of geophysical techniques to locate small anomalies, such as those that contain children or infants. As such, the aim of this study is to assess ground penetrating radar (GPR) and electrical resistivity tomography's (ERT) ability to detect a series of ten small graves with differing contents - seven containing one clothed stillborn piglet each (to mimic child or infant burials), and three controls with differing contents (one empty, and then one with a wooden stake and one with a metal crowbar - to mimic evidence stashes) - over a four-month period. Additionally, one pig cadaver was excavated after each monthly survey until full skeletonisation to corroborate the stage of decomposition with geophysical detectability. The results demonstrate that two-dimensional (2D) GPR (450 MHz) could consistently detect each of the ten graves across the survey period, regardless of the grave contents and phase of decomposition; however, the metallic object grave was the most obvious. Conversely, 2D ERT (64 electrodes at a 0.25 m spacing; Dipole-Dipole and Wenner arrays) observability was highly inconsistent. Practically, this research highlights that mid-frequency 2D GPR was able to detect simulated child burials and was preferable to ERT at the chosen survey parameters.