FORENSIC GROUND PENETRATING RADAR FOR THE IMPROVED MANAGEMENT OF CEMETERIES AND GRAVESITES, TEXAS USA

Forensic Ground Penetrating Radar (GPR) is quickly becoming the method of choice for cemetery and graveyard management projects. The non-invasive nature of the technique is preferred over other techniques such as probing or exhumation. Some cemeteries have even begun to retain the services of licensed geoscientists to improve management of their facilities and to aid with some of the daily operations.

This poster presents a compilation of several forensic investigations conducted by the author throughout the state of Texas. The two main questions a cemetery or gravesite manager wants answered are: How much available space is left, and where are the locations of any unmarked graves within the facility? Other questions posed can range from finding space between two graves to finding unmarked graves outside the current limits of a private family graveyard. The answers to these questions are usually provided by the geoscientist in the form of technical reports containing 2-dimensional radar profiles for small projects and maps constructed from the 2-D profiles for large projects of 1 acre or more.

The most practical (GPR) frequency to operate at in Texas is 100MHz. At this frequency the vertical resolution limits of the radar system are dependent upon the pulsewidth (10 ns) and velocity of the radar waves (.07-.1m/ns) which yields 18-25 centimeters (~8-10 inches). The horizontal resolution is dependent upon the velocity of the radar waves (~.07-.1m/ns), the pulsewidth (10ns) and the distance to the target (usually 1.5meters) which yields approximately 50-60cm (20-24 inches). Operation at higher frequency can produce higher resolution results but can be detrimental to the study if water or moist clays are present. The depth of penetration is inherently decreased by an increase in frequency and the increased resolution may produce cluttered (noisy) radar profiles that are very difficult to interpret.