Evaluating the reliability and accuracy of multiple geophysical methods in the search for clandestine graves

This project examines the forensic application of three geophysical methods in the search of clandestine burials: ground penetrating radar (GPR), electromagnetic conductivity (EM), and magnetometry. The goal of this basic research is to provide the National Institute of Justice data on the reliability and accuracy of these geophysical methods, including false positive and false negative error rates. In order to achieve this goal, a two-year project with three data collection events is proposed. While prior studies have investigated the forensic application of geophysical techniques, these studies almost exclusively relied on animals as human proxies or involved recent interments. Law enforcement agencies are increasingly encouraged to acquire GPR and other geophysical methods for successful resolution of cases involving buried remains (i.e. FINDAR speaks for Murder Victims, 2016). As such, calculating error rates for the application of GPR, EM, and magnetometry in the search for buried human remains is critical.
The Anthropology Research Facility (ARF) at The University of Tennessee, Knoxville, provides an optimal setting to collect geophysical data on human interments and to compare the geophysical data to the actual evidence. A study of 20 human burials using three geophysical methods with different transect and instrument settings will be carried out across varied terrain. The scans will be compared with known burial data to assess the applicability and reliability of geophysical instrumentation for searches involving burials older than a year old. Data on pit morphology and depth and presence or absence of remains will be evaluated against geophysical data. These comparative data will allow the calculation of an accuracy score to examine the fidelity of the geophysical method. In addition, geophysical data analysts will analyze an additional 20 human burials in 5 areas of interest to determine the presence or absence of burials. Their analysis will be compared with known presence of burials to provide a false negative and positive rate for each method. Finally, time of equipment set-up and take-down, surveying, and data processing will be recorded to compare with equipment cost and accuracy to provide law enforcement with data on which method may be the most cost- and time-effective in clandestine burial searches. This project will identify the variables and sampling thresholds for successful detection of buried human remains using GPR, EM, and magnetometry thereby improving the effectiveness and outcomes of criminal investigations. Deliverables for this effort will consist of financial, semi-annual, and final research reports. CA/NCF