USING GEOPHYSICAL METHODS TO STUDY CEMETERIES

Geophysical methods can often resolve problems facing cemeteries in northern New York. For example, in a military cemetery at Sacketts Harbor, NY rows of headstones were removed from gravesites and put back in the wrong place. St. Mary's cemetery at Potsdam faces the problem of large boulders in glacial till which increases the cost of graves significantly. Several seismic refraction traverses were conducted in the cemetery indicating a low velocity material extending to a depth of 5 feet. This is the material that contains the graves. The linearity of the travel time curves indicates the material is fairly homogenous and does not contain numerous boulders, which would scatter travel time data.

At the Hillcrest cemetery in Parishville, NY sites of several unmarked graves have been lost or destroyed. In an attempt to locate these graves, electrical resistivity profiling was conducted in the vicinity where the graves were thought to occur. A Terrameter SAS 300C was used to conduct the resistivity surveys. Resistivity measurements were made at two foot intervals and at an electrode spacing of 10 feet. Hillcrest cemetery is located in sand deposits of an ancient shoreline of Lake Iroquois. The resistivity profiles indicate that high resistivity values greater than 1000 ohm-meters occur throughout the cemetery. These high values are due to the sandy deposits. The profiles also reveal that variations in the resistivity occur. The lower values of resistivity are attributed to clay and water in the sand. The profiles show that small resistivity highs occur over the gravesites. These small resistivity highs were used as a guide to locate the unmarked graves.