Long-term sequential monitoring of controlled graves representing common burial scenarios with ground penetrating radar: Years 2 and 3

Schultz, John J.; Walter, Brittany S.; Healy, Carrie

doi:10.1016/j.jappgeo.2016.06.015

Cited by 11 publications

(10 citation statements)

References 31 publications

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“…The naked cadaver was not well detected in either low (110 MHz) or high (900 MHz) frequency surveys, and only poorly detectable at medium frequencies (225/450 MHz). This was comparable to similar, shorter timescale monitoring studies 16,41,42 , with the naked cadaver attenuating GPR signal as other researchers have noted 16,57 . This radar absorption would be exacerbated by the chest cavity collapsing during the later stages of decomposition (Fig.…”

Section: How Detectable Was a Buried Naked Cadaver Over Time?supporting

confidence: 88%

“…When is the optimal time post-burial to do a forensic geophysical survey. From the results shown in this study and others 16,29,35 , irrespective of burial style (and vertical burials have been evidenced 65 ), there is a general reduction in geophysical anomaly amplitude with increase in time since burial, so the sooner geophysical surveys can be undertaken the greater the chance of discovery (see Table 1 for general summary). Geophysical surveys should preferably be conducted prior to other, more invasive search methods, which may disturb the ground and introduce false-positive anomalies (e.g.…”

Section: How Detectable Was a Buried Wrapped Cadaver Over Time? Wrapsupporting

confidence: 69%

“…contained a naked pig cadaver whilst an adjacent burial contained a pig cadaver wrapped in tarpaulin, the latter frequently used in order to assist with body transportation and concealment. It is, however, emphasised that these do not represent all types of burial style with others 16 detailing other typical burial scenarios.…”

mentioning

confidence: 99%

“…Geophysical surveys over simulated burials are undertaken to collect control data [36][37][38][39][40] and to predict what geophysical responses could be in search cases, although the actual response will vary both temporally and between study sites. A few geophysical control surveys have also collected repeat (time-lapse) data 16,29,[41][42][43][44][45][46] . However, at present, a detailed understanding of the temporal persistence of the post burial geophysical anomaly remains unknown due to the time and effort required to collect control data over many years.…”

mentioning

confidence: 99%

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Geophysical monitoring of simulated homicide burials for forensic investigations

Pringle

Stimpson

Wisniewski

et al. 2020

Sci Rep

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finding hidden bodies, believed to have been murdered and buried, is problematic, expensive in terms of human resource and currently has low success rates for law enforcement agencies. Here we present, for the first time, ten years of multidisciplinary geophysical monitoring of simulated clandestine graves using animal analogues. Results will provide forensic search teams with crucial information on optimal detection techniques, equipment configuration and datasets for comparison to active and unsolved cold case searches. electrical Resistivity (eR) surveys showed a naked burial produced large, lowresistivity anomalies for up to four years, but then the body became difficult to image. A wrapped burial had consistent small, high-resistivity anomalies for four years, then large high-resistivity anomalies until the survey period end. Ground Penetrating Radar (GPR) 110-900 MHz surveys showed the wrapped burial could be detected throughout. 225 MHz GPR data was optimal, but the naked burial was poorly imaged after six years. Results suggested conducting both eR and GpR surveys if the burial style was unknown when searching for interred remains. Surveys in winter and spring produced the best datasets, and, as post-burial time increases, surveying in these seasons became increasingly important. this multidisciplinary study provides critical new insights for law enforcement and families of the disappeared worldwide. Available statistics for missing persons globally vary. For example, in the United Kingdom, ~250,000 are reported missing every year, but, of those, only ~2,500 are still missing after a year 1. In the United States, ~650,000 are reported missing every year, but only ~90,000 are still missing after a year 2. Whilst these still missing numbers are comparatively small, for the families of the missing it is obviously of crucial importance for them to be found, not only for closure if they have been the victim of a homicide, but also to know that justice for the perpetrator(s) has been served. However, current success rates to find the missing are low, with high profile examples being Madeleine McCann in Portugal and Ben Needham in Greece, sadly both presumed dead. Forensic search methods vary widely. A search strategist may be involved in a case at an early stage to decide which methods would have the highest probability of search success 3 , but this is not for every case globally, and investigations may not be standardised or indeed different techniques undertaken, depending on local experience 4. Metal detector search teams 5-7 and specially-trained victim recovery dogs 7-9 are both commonly used during initial investigations or as part of phased sequential search programmes. Forensic investigators have been increasingly using geoforensic methods in civil or criminal forensic investigations, predominantly to assist search teams as they attempt to locate missing persons or for trace evidence purposes 10-13. Locating homicide victims buried within clandestine graves is one of the most important and difficult ch...

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Section: How Detectable Was a Buried Naked Cadaver Over Time?supporting

confidence: 88%

Section: How Detectable Was a Buried Wrapped Cadaver Over Time? Wrapsupporting

confidence: 69%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Geophysical monitoring of simulated homicide burials for forensic investigations

Pringle

Stimpson

Wisniewski

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…In recent years, ground penetrating radar (GPR), which allows for rapid and real-time measurements, has received great attention for nondestructive testing (NDT). This technique has been applied for pavement investigation [ 4 ], geological exploration [ 5 ], civil engineering [ 6 ], subsurface archaeological investigation [ 7 ] and thin-layer thickness estimation [ 8 ]. In the forestry field, GPR has provided an important method of root system architecture reconstruction [ 9 ], root diameter or biomass estimation [ 10 ], and moisture content [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Application of Ground-Penetrating Radar for Detecting Internal Anomalies in Tree Trunks with Irregular Contours

Wen

Zhang

et al. 2018

Sensors

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To assess the health conditions of tree trunks, it is necessary to estimate the layers and anomalies of their internal structure. The main objective of this paper is to investigate the internal part of tree trunks considering their irregular contour. In this respect, we used ground penetrating radar (GPR) for non-invasive detection of defects and deteriorations in living trees trunks. The Hilbert transform algorithm and the reflection amplitudes were used to estimate the relative dielectric constant. The point cloud data technique was applied as well to extract the irregular contours of trunks. The feasibility and accuracy of the methods were examined through numerical simulations, laboratory and field measurements. The results demonstrated that the applied methodology allowed for accurate characterizations of the internal inhomogeneity. Furthermore, the point cloud technique resolved the trunk well by providing high-precision coordinate information. This study also demonstrated that cross-section tomography provided images with high resolution and accuracy. These integrated techniques thus proved to be promising for observing tree trunks and other cylindrical objects. The applied approaches offer a great promise for future 3D reconstruction of tomographic images with radar wave.

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A methodology for the self‐training and self‐assessing of new GPR practitioners: Measuring diagnostic proficiency illustrated by a case study of a historic African‐American cemetery for unmarked graves

Martin

Everett

2023

Archaeological Prospection

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In ground penetrating radar (GPR) surveys of African‐American cemeteries suspected to contain unmarked graves, determining the proficiency of a new GPR practitioner is vital and perhaps even more fundamental than that of the GPR hardware, deployment configuration and software. Proficiency may be defined as the practitioner's true‐positive, true‐negative, false‐positive (i.e., false alarms) and false‐negative (i.e., misses) percentages. We embarked on this research as a means to improve our own proficiency in unmarked grave detection and to develop an algorithm by which to improve the proficiency of any new GPR practitioner. After surveying the Salem Cemetery in Brazos County, TX, and the Old Danville‐Shepherd Hill Cemetery in Montgomery County, TX, we first classified subsurface targets based on in‐field, visual inspection of the real‐time, onscreen, unprocessed (except for an automatic gain control) GPR B‐scans. We then developed a proxy for ground‐truthing that allowed us to calculate the proficiency of the in‐field classifications. From this proxy, we established a quantitative prevalence threshold for identifying or rejecting a subsurface object as a target of interest. Its quantitative nature allowed us to quantitatively control and adjust that threshold, a threshold we set at 70% likely to be to a specific target of interest. We show that our classification accuracy increased from 66.2% at the Salem Cemetery to 75.0% at the Old Danville‐Shepherd Hill Cemetery and, through use of diagnostic evaluations originally developed for medical imaging and herein applied to geophysics, showed that the accuracy improved due to increases in true‐negative classifications, that is, in examining real‐time, onscreen, mostly unprocessed GPR B‐scans, discerning a potential target and correctly concluding it was not an unmarked grave. This research outlines the procedure we developed to measure the proficiency of a new GPR practitioner.

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Long-term sequential monitoring of controlled graves representing common burial scenarios with ground penetrating radar: Years 2 and 3

Cited by 11 publications

References 31 publications

Geophysical monitoring of simulated homicide burials for forensic investigations

Geophysical monitoring of simulated homicide burials for forensic investigations

Application of Ground-Penetrating Radar for Detecting Internal Anomalies in Tree Trunks with Irregular Contours

A methodology for the self‐training and self‐assessing of new GPR practitioners: Measuring diagnostic proficiency illustrated by a case study of a historic African‐American cemetery for unmarked graves

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