Booth, AD and Pringle, JK (2016) Semblance analysis to assess GPR data from a five-year forensic study of simulated clandestine graves. Journal of Applied Geophysics, 125. pp. 37-44. ISSN 0926-9851
Abstract
Ground penetrating radar (GPR) surveys have proven useful for locating clandestine graves in a number of forensic searches. There has been extensive research into the geophysical monitoring of simulated clandestine graves in different burial scenarios and ground conditions. Whilst these studies have been used to suggest optimum dominant radar frequencies, the data themselves have not been quantitatively analysed to-date. This study uses a common-offset configuration of semblance analysis, both to characterise velocity trends from GPR diffraction hyperbolae and, since the magnitude of a semblance response is proportional to signal-to-noise ratio, to quantify the strength of a forensic GPR response. 2D GPR profiles were acquired over a simulated clandestine burial, with a wrapped-pig cadaver monitored at three-month intervals between 2008 and 2013 with GPR antennas of three different centre-frequencies (110, 225 and 450 MHz). The GPR response to the cadaver was a strong diffraction hyperbola. Results show, in contrast to resistivity surveys, that semblance analysis show little sensitivity to changes attributable to decomposition, and only a subtle influence of seasonality: velocity increases (0.01–0.02 m/ns) were observed in summer, associated with a decrease (5–10%) in peak semblance magnitude, SM, and potentially in the reflectivity of the cadaver. The lowest-frequency antennas consistently gave the highest signal-to-noise ratio although the grave was nonetheless detectable by all frequencies trialled. These observations suggest that forensic GPR surveys could be undertaken with little seasonal hindrance. Whilst GPR analysis cannot currently provide a quantitative diagnostic proxy for time-since-burial, the consistency of responses suggests that graves will remain detectable beyond the five years shown here.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 Elsevier B.V. All rights reserved. This is an author produced version of a paper published in Journal of Applied Geophysics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Forensic search; Clandestine grave; GPR; Semblance analysis |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Jan 2016 13:50 |
Last Modified: | 20 Dec 2016 23:07 |
Published Version: | http://dx.doi.org/10.1016/j.jappgeo.2015.11.016 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jappgeo.2015.11.016 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:93304 |