HISTORY, HIGH SCHOOLERS, AND GEOPHYSICS: USING GROUND PENETRATING RADAR TO LOCATE UNMARKED GRAVES IN TOLEDO, OHIO, USA

A pauper's cemetery in Toledo, Ohio has been a source of long-standing community history. The site was the burial location for the nearby public mental hospital from 150 years ago to an unknown date. The property sits adjacent to Bowsher High School and provides an easy access study site for students involved in an NSF funded GK-12 research internship. It is known that the cemetery hosts many unmarked graves but the numbers and boundaries of burial locations are uncertain. A magnetometer study completed at this site showed several small dipole anomalies with particularly dense anomalies, some of which are associated with small marker stones, in the western half of the site.

Ground penetrating radar (GPR) is a non-invasive method of detecting shallow subsurface features as reflections of an electromagnetic signal. GPR has been used in many studies to detect unmarked graves. The objectives of this project are to (1) use GPR to support the possibility that dipole anomalies mark the locations of unmarked graves and (2) to allow high school students to conduct research that has observable societal impacts.

Several transects were completed using 200 MHz antennas, a step size of 0.25 m, and 0.5 m separation. Transects were spaced 1.0 meter apart and run north-to-south across the western half of the study site. Anomalies appeared on each transect with a possible pattern. The anomalies often repeated at the same distance along the different transects indicating ground disturbances 1 to 2 meters long that are comparable to human graves. Transects were also run over known graves for comparison. The locations of the anomalies were mapped along with the known graves to provide an idea of the total number and distribution of burial locations in the study area.

In planning and conducting this project students learned how to implement the scientific method with a unique purpose and multidisciplinary tactics. Grave location information will be used by the Toledo State Hospital Cemetery Reclamation Project to place grave markers, further their understanding of the site at large, and encourage appreciation for the unspoken history it represents.