WASHINGTON, December 5, 2016 – Ground penetrating radar (GPR) is technology that has been used by the construction industry, archaeological industry, and the law enforcement industry, among others, to find things hidden by time and lost records.
Cemetery mapping is another advancement that GPR has made possible. Using ground penetrating radar to find unmarked graves or to update historical grave site information is yet another tool in preserving our past.
As the need for developable land increases, our history is being paved over as urban sprawl moves into our more urban areas. In those small rural towns are family and church graveyards that may have been lost to history and that are at risk of being turned into parking lots and apartment buildings.
By using GPR, builders and historians are able to peer beneath the surface to find the history buried there. In Cole County, Missouri, a founding families cemetery was buried beneath a paved roundabout for a subdivision.
Lloyd Klosterman’s family once owned the property just west of Jefferson City, Missouri. The 2,000 acre farm was owned by the Dixon family more than 150 years ago in the early 1800s. Not only is the Dixon family cemetery believed to now be a roadway, but the family owned slaves that were also buried on the farm.
Mr. Klosterman told ABC 17, Missouri, that slaves cleared the trees to turn the property into a working farm and that many of those slaves are believed to be buried just north of the roundabout, including the headstones that were allegedly laid across the graves and covered over.
Ground penetrating radar was used to investigate and it is believed that the Dixon family, and their headstones were knowingly buried beneath the pavement and the issue is being further investigated following the news agency’s reporting and there is the possibility of criminal charges. Disturbing, destroying, vandalizing, or damaging a marked or unmarked human burial site is a class E felony. The stature further reads that every person who shall knowingly destroy, mutilate, disfigure, deface, injure, or remove any tomb, monument, or gravestone, or other structure placed in such cemetery or burial ground or place of burial of any human being, is guilty of a class A misdemeanor.”
Locating Unmarked Graves
During the Civil War, burying war dead in unmarked grave sites was a regular occurance for soldiers and slaves and while there might be local lore that identifies that burials took place, is difficult to find an exact area that the graves might be.
Ground penetrating radar can determine the presence of subsurface irregularities, such as grave shafts or stones hidden below the surface. There are a number of factors that affect the accuracy of GPR depending on different types of material that the radar is going through.
A depth target is calculated based on the amount of time it takes for the radar signal to be reflected back to the antenna. Since the radar travels at different velocities based on different materials, the velocity estimation is usually accurate within 10%.
Mapping Old Cemeteries
There are many cemeteries that that house the remains of some of America’s most notable figures. With every passing year documents and records get lost, graves get shifted, and plots become indistinguishable. GPR systems are used for upkeep in these historical areas.
The Historic Congressional Cemetery in Washington, DC was recently surveyed using GPR and, as of December of 2013, over 2,750 unmarked burials were found. Founded in 1807, the cemetery still conducts burials and being able to map the cemeteries is essential in order to ensure that new burials sites aren’t already inhabited.
The uses for GPR go beyond finding the final resting place of the dead. Ground penetrating radar can be used to locate utilities during construction, assessing landfill limits, locating cracks in a concrete structure, managing groundwater, or helping forensic investigators find objects hidden in walls.
The practices and technology used for cemetery mapping is very similar to other archaeological applications including artifact locating and structure mapping. Without this technology, so many facets of history could be lost to the ravages of time. Finding unmarked graves, and mapping old cemeteries is just one aspect of GPR that is extremely important for preserving the memory of many lost members of our history.