In cemeteries across the United States, there are “the forgotten” burials of unmarked and lost graves. Geophysical techniques, such as Ground Penetrating Radar (GPR), are needed to nondestructively locate these burials in cemeteries and in other locations. Here, we discuss the common causes for lost graves and present three keys to survey success.

Common Causes for Lost Graves

There are many causes for lost, unmarked graves, but two of the most important are cemetery age and population growth.

Historical cemeteries can go back hundreds of years. Over time, missing, fallen, or poorly placed headstones can complicate the assumed physical location of grave sites. The original documentation may be unavailable or rendered unreadable, further leading to confusion. For these and other reasons it is common for cemetery maintenance managers, or other stakeholders, to enlist GPR service providers to generate up-to-date burial maps or clear areas for new burials.

Modern population growth has led to increased infrastructure and city sprawl. As local and state regulations have evolved over time there are documented cases where contractors were given permission to build over known or forgotten burial grounds. In these situations, it is possible that civil and political pressure may lead to a GPR investigation to determine the existence of a cemetery, presence or absence of burials, whether the graves have been disturbed, and factors related to relocation recommendations. In other cases, cemeteries were relocated due to urban expansion but some of the graves could have been overlooked.

Due to the sensitivity of these sites, the GPR service provider’s challenge is to quickly explore the subsurface without disturbing the burials. Every cemetery is different, and local environmental and soil conditions can complicate the investigation. Below, we outline three steps to get started in mapping cemeteries.

How to Get Started: Three Keys to Success

1. Know your GPR Equipment – Experienced users with knowledge of archaeology, forensics, and burial practices are best suited for cemetery mapping surveys. However, for beginners there are many pathways for acquiring sufficient knowledge and experience. The first key to success is to determine the right type of equipment to use and to know one’s GPR equipment well. All the archaeological, forensic, or cemetery knowledge in the world is not a substitute for GPR gear and an understanding of how to use it effectively.

Learn from a Registered Archaeologist, the GSSI Academy offers classes specific to cemetery mapping and equipment use.

2. Conduct Pre-Survey Research –
   • Practice: The best experience is hands-on practice. Consider reaching out to a local cemetery and ask permission to scan their grounds prior to conducting cemetery surveys as a service offering.
   • Research: Take time to research the age of the cemetery and how it may have been managed over time. For example, were any plots of land adjacent to the cemetery purchased or changed over time? Is there a clear property line boundary or is it possible that burials could be edging the property? Additionally, seek out research materials that describe GPR methods for cemeteries and become familiar with how burials appear in GPR datasets.
   • Directionality: Look at the existing marked graves in the cemetery to determine the direction and orientation of the graves. For example, if there is no surface expression, can the headstone or footstone provide directional orientation? This will aid in determining the direction of data collection and achieve a better-quality survey result. Ideally, the GPR should pass over burials perpendicular to their long axis (90 degrees).
3. Consider the Variables – Soil conditions, weather, and the surrounding environment are variables that can affect the quality of the GPR survey. Note these observances in your field notes and determine if other geophysical techniques can be used to compliment the GPR survey. Be especially cautious if the ground is saturated with water. If your shoes ‘squish’ when you walk over the site, consider returning once the water content has decreased. Look for large trees in the vicinity, signs of large rocks and animal burrows. These and other targets could generate ‘false positive’ indicators of burials.

Data Collected with GSSI UtilityScan

With this application, it is just as important to understand the appropriate type of GPR equipment, as well as potential limitations, as it is to know about what you’re going to encounter onsite. As with all technical subjects, mastery of cemetery investigations with GPR requires practice and dedication. Armed with GSSI GPR and an understanding of burial characteristics, you can help locate and protect human burials.

We’re here to help – we’re educators and want to provide you with the tools to be successful. To learn more, here are some recommended readings:

Recommended Reading

1. Bevan, B. W. The search for graves. 1991. Geophysics, 56(9), pp. 1310-1319
   • Can be downloaded from Bruce Bevan’s Academia.edu page (requires login or sign up)
2. Conyers, Lawrence B. Ground-penetrating radar for archaeology. Altamira Press, 2013.
3. Conyers, Lawrence B. Interpreting ground-penetrating radar for archaeology. Routledge, 2016.
4. Conyers, Lawrence B. “Ground-penetrating radar techniques to discover and map historic graves.” Historical Archaeology3 (2006): pp. 64-73.
   • Downloadable from Conyers’ website: http://www.gpr-archaeology.com/wp-content/uploads/2018/01/graves.pdf
5. Leach, Peter. RADAN 7 for archaeology, forensics, and cemeteries. Geophysical Survey Systems, Inc. 2019, pp. 70
   • Downloadable from GSSI’s website: https://www.geophysical.com/wp-content/uploads/2019/04/MN43203A-RADAN-for-Archaeology-Cemeteries-and-Forensics.pdf

Recent Articles

1. Guzzo, Paul, “Are there graves under Tropicana Field parking lots? Archaeologists want to find out,” Tampa Bay Times, July 2, 2020, https://www.tampabay.com/news/st-petersburg/2020/07/02/are-there-graves-under-tropicana-field-parking-lots-archaeologists-want-to-find-out/
2. Fortin, Jacey and Diaz, Johnny, “A Long-Lost Black Cemetery in Tampa May Have Been Found,” New York Times, November 27, 2019, https://www.nytimes.com/2019/11/27/us/tampa-black-cemetery-school.html
3. Schreiner, Mark, “USF Researchers Plan Return to Dozier,” WUSF Public Media, October 2, 2019, https://wusfnews.wusf.usf.edu/post/usf-researchers-plan-return-dozier

We will continue to explore the cemetery mapping application with additional blog posts. Stay tuned to learn how to conduct two-dimensional (2D) and three-dimensional (3D) cemetery surveys and the advantages and disadvantages of each method. Curious about system recommendations? Please reach out to us via: Contact Us