Archaeological investigation of burials preluded by ground penetrating radar and geospatial technologies

Abstract

Ground penetrating radar (GPR) is a non-invasive and efficient scientific tool in burial analysis that can 'see the unseen,' answering both simple questions such as the existence and boundaries of burials, as well as more difficult questions like whether burials are intact or decayed. This paper reviews common reflection signatures associated with burials and applies the three fundamental GPR principles (dielectric contrast, scattering and polarity of reflections) to two distinct caseworks involving historical graves and civilian burials, which serve as benchmarks with known ground truth. It encompasses a third test case involving family tree research in a civilian cemetery, drawing upon the benchmarked results obtained from the first two caseworks. In adherence to geophysical signal reflection principles, our study discerns distinct hyperbolic traits associated with three burial types including intact shroud-wrapped, coffin burials, and decayed or mass-grave burials. A GPR-geospatial integration workflow incorporating GPR, aerial photogrammetry and global navigation satellite system - real time kinetics (GNSS-RTK), is derived to enhance the identification and investigation of burials using GPR. Our workflow encompasses a range of indicators for survey methods and burial classification, presenting a general framework for the systematic contextualization of tailored workflows to individual contexts. This work exemplifies the efficacy of GPR in the detection of burials that have been undisturbed for over a century in the soils of Hong Kong and how geophysics and geospatial science can address the limitations inherent in conventional desktop-based archaeological investigation. Its implications extend to professionals in diverse fields including historians, archaeologists, cemetery management officials, and even family members searching for their lost loved ones.