Long-term Sequential Monitoring of Controlled Graves Representing Common Burial Scenarios With Ground Penetrating Radar: Years 2 and 3

• NCJ Number: 251294
• Journal: Journal of Applied Geophysics Volume: 132 Dated: September 2016 Pages: 60-74
• Author(s): J. J. Schultz; B. S. Walter; C. Healy
• Date Published: September 2016
• Length: 15 pages
• Grant Number(s): 2008-DN-BX-K132
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored); Program/Project Description

Annotation

This study examined the applicability of ground-penetrating radar (GPR) for detecting controlled graves in a Spodosol representing multiple burial scenarios for Years 2 and 3 of a three-year monitoring period, with the objectives of determining how different burial scenarios are factors in producing a distinctive anomalous response; determining how different GPR imagery options (2D reflection profiles and horizontal time slices) can provide increased visibility of the burials; and comparing GPR imagery between 500 MHz and 250 MHz dominant frequency antennae.

Abstract

Geophysical techniques such as GPR have been successfully used for forensic searches to locate clandestine graves and physical evidence; however, additional controlled research is needed to fully understand the applicability of this technology when searching for clandestine graves in various environments, soil types, and for longer periods of time post-burial. The research site for the current study contained a grid with eight graves representing common forensic burial scenarios in a Spodosol, a common soil type of Florida, with six graves containing a pig carcass (Sus scrofa). Burial scenarios with grave items (a deep grave with a layer of rocks over the carcass and a carcass wrapped in a tarpaulin) produced a more distinctive response with clearer target reflections over the duration of the monitoring period compared to naked carcasses. Months with increased precipitation were also found to produce clearer target reflections than drier months, particularly during Year 3 when many grave scenarios that were not previously visible became visible after increased seasonal rainfall. Overall, the 250 MHz dominant frequency antenna imagery was more favorable than the 500 MHz. Although detection of a simulated grave may be difficult to detect over time, long-term detection of a grave in a Spodosol may be possible if the disturbed spodic horizon is detected. Furthermore, although grave visibility increased with the 2D reflection profiles, particularly with the 250 MHz antenna, the combination of both imagery options is recommended when evaluating GPR data during a search for a clandestine grave. (Publisher abstract modified)