USING GROUND PENETRATING RADAR IN SEARCH OF UNMARKED GRAVES AT THE OLD BURYING GROUND, STONEHAM MASSACHUSETTS

Reconnaissance of the shallow subsurface is often necessary for forensic, archaeological, and environmental applications, and geophysical technologies provide efficient and cost-effective means to conduct such work in a non-destructive fashion. In the current study, Ground Penetrating Radar (GPR) was used as a tool to constrain possible unmarked grave locations in the Old Burying Ground (OBG), Stoneham, MA. The location was glaciated during the late Pleistocene, and surficial maps show thin till with adjacent stratified drift. The OBG was the burial ground from the town’s founding during the colonial period until the 1800s. There are a number of areas lacking burial markers, and church records from the time document the presence and deaths of slaves. Due to the practices of the time and the church records confirming deaths,we hypothesize that there are unmarked graves in the OBG. We focused on an L-shaped plot of land that is conspicuous in its lack of tombstones. Using a GSSI GPR with 350HS antenna, continuous GPR records were recorded along N-S and E-W gridded perpendicular lines spaced 12 inches apart, and all data were post-processed using Radan 7 software. A control line was recorded horizontally across a series of known graves to calibrate the interpretation of subsurface anomalies. This initial line demonstrated that known bodies are represented by geophysical anomalies characterized by visible and clear disturbances in the subsurfaces, creating a region that lacks any discernible features in the sediment. These gaps appear at the spot where the tombstones are located, which suggests that the anomalies are due to the presence of graves. Data collected in the gridded study area revealed a number of anomalies present at the site. Of the scans, one in particular stood out for its noticeable pattern of disturbances around six feet deep, consistent with typical burial depths. The control line contained similar anomalies in places where the tombstones indicated that there were graves. This pattern shows consistencies with the known graves: a visible gap that breaks up the subsurface stratigraphy. They are evenly spaced in such a way that such a formation would be surprising to see form naturally. Based on historic records from the period, the observed GPR anomalies are interpreted as the likely location of unmarked graves.