Ground-Penetrating Radar (GPR) Survey and Spatial Analysis of the George and Addie Giddens Cemetery, Opelika, AL

Abstract

Recent interest in locating and preserving the cemeteries of enslaved African Americans has increased the need for non-invasive geophysical techniques and efficient methodologies. The southeast United States provides many challenges to ground-penetrating radar (GPR) usage due to its humid climate and abundant vegetation that deteriorate burial remains, disguise burial shafts, and provide physical barriers to GPR surveys. These challenges make it difficult for many existing methodologies, which typically focus on locating caskets or burial shafts. In addition, GPR data typically are unable to provide information regarding potential decay rates and burial ages. Determining burial ages would be useful information for reconstructing the cemetery history, geophysical interpretation, and for understanding burial decay rates. To address these issues, this study uses GPR in combination with spatial and visual analyses to attempt to locate burials in a humid climate. A quantitative value system is used to determine the condition of potential burials and to allow spatial analyses to be performed. This combined effort led to the location of 129 potential burials. The spatial distribution of burial conditions allowed for the comparison between relative burial ages and decay rates within the cemetery site and highlighted statistically significant clustering of burials.