Using 3D GPR to determine the extent of possible 17th and 18th century graves beneath a concrete driveway:: Bridgetown synagogue, Bridgetown, Barbados.

At Bridgetown, Barbados is one of the oldest synagogues in the western hemisphere. During a period of disuse, a part of the cemetery was paved over by a car park and a driveway. Currently, the synagogue and particularly the cemetery are in the process of an extensive restoration and removal of the driveway is contemplated. We used GPR to investigate whether historic burials beneath the driveway could be detected. "Control" profiles in the (uncovered) part of the cemetery revealed a distinctive pattern of strong reflectors that is consistent with stones and/or brick grave foundations in the subsurface. A somewhat chaotic pattern of reflectors is also noted, which is consistent with disturbed ground. Profiles taken over the driveway are less distinctive. This is perhaps due to construction methods that homogenized the substrate. In addition, depth of penetration using the available 900 MHz antennas was similar to1.2 m. Map-view depth slices over the driveway are likewise less than conclusive, although we did clearly image a buried utility. We note some small, medium-amplitude anomalies beneath the drive that may be caused by stones or by grave-foundation bricks. While GPR shows promise as a tool for helping direct driveway removal and complete cemetery restoration, future GPR applications here should use lower-frequency antennas in an effort to penetrate to at least 2 m.