Combined time-lapse 3D GPR and resistivity investigations on simulated clandestine burials in complex urban environments

The use of non-invasive geophysical methods in criminal in-vestigations is still relatively uncommon especially when com-pared to more conventional methods (e.g., aerial and remote sensing, cadaver dogs, excavation, etc.). Near-surface geophys-ical techniques, and particularly ground-penetrating radar (GPR), have been used with varying degrees of success to lo-cate clandestine graves, but multi-disciplinary studies have shown that cadaver detection is generally problematic after a long period of burial. Since the success of geophysical tech-niques is predominantly dependent upon the contrast between the target and host materials, there is a need for scientific re-search to try and quantify both target and site variables and how they may change over time which may therefore affect forensic burial detection.
This paper reports on recent near-surface high-frequency (450 and 900 MHz) GPR surveys over two contrasting simulated clandestine burial case studies in a difficult urban environ-ment: a simulated 12 year old adult burial and a recent juve-nile burial using contrasting materials.
Accurate GPR data processing, integration and 3D visualiza-tion (time-slice) techniques were essential to recognize and isolate the often subtle GPR anomalies over ‘graves’ in this complex, urban environment. GPR results compared well with bulk ground resistive anomaly locations, although GPR was higher resolution, better resolved the older burial and provid-ed a depth estimate to the buried target.