A proposed search strategy for the use of drones in detecting unmarked burials

Abstract

Drone detection of clandestine burials is an emerging field lacking a comprehensive dataset that demonstrates detection across complex variables of burial environments. This study summarises published trends in drone-derived burial signatures and complements them with 20 additional case studies comprising burials in a variety of contexts, which use three primary drone outputs for grave detection: orthomosaics, digital surface models, and vegetation indices.

Study sites include analogue case studies, which are natural burial sites that act as proxies for clandestine burials; forensic case studies, which imply a criminal element to burial; and historical/archaeological case studies, which involve burials over 100 years old. These 20 study sites, encompassing over 1,000 burials, include successful detection across three continents, glaciated terrain and residual soils, arctic and equatorial climates, and burial ages from weeks to over 134 years old. In addition, GPR data was collected at seven of these sites to verify drone anomalies.

Expressions of burial anomalies in each of the three primary drone outputs for all 20 sites are summarised below. Anomalies from graves ranging from interment to 107 years old are detected using visual changes in RGB orthomosaics. Burials detected using digital surface models begin as mounds, level out between two and three years post-burial and become depressions detectable up to 134 years. Vegetation indices, such as NDVI, are useful in detecting ground disturbances where bare soil is easily differentiated from healthy vegetation, as well as quantifying the health of pioneer vegetation, which was able to distinguish grave and non-grave vegetation in burials up to 107 years old.

Lessons learned in the drone search process as well as burial trends established over these 20 sites and published studies are integrated into a Geoforensic Drone Search Protocol, which not only demonstrates a step-by-step guide to conducting clandestine grave searches using drones but serves as a decision-making tool whereby investigators can set expectations, prioritise outputs, conduct necessary desk study and site preparation, and select supplementary search tools.

Thesis embargoed until 31st December 2026.

Date of Award	Dec 2025
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Alastair Ruffell (Supervisor) & Graeme Swindles (Supervisor)