One of the vexing problems with old cemeteries and historical sites is the difficulty of finding the locations of unmarked graves. In many cases, the desire is to locate the graves so that they may be identified and left undisturbed by new construction. To be sure, the locations may have been marked at one time with wooden or even stone markers. However, the ravages of time, weather, animals, vandals, and acid rain over the years may have removed all traces of those markers. Locating unmarked graves is also vitally important in solving murder cases.
Historically, the only method of finding unmarked graves has been to start digging – not a very practical solution. However, modern technology now allows cemetery associations, historical societies, family societies, genealogists, archaeologists, police departments, and others to identify the locations of buried bodies and other objects with no digging required.
Ground penetrating radar systems (GPRS) work in a similar manner to normal radar systems: a radio signal is transmitted, and the reflected radio wave is measured and then displayed on a screen or printer, showing the distance and size of objects. We normally think of aircraft radar as measuring distances of airborne objects many miles away. However, the same technology works in the ground, measuring distances of a very few feet.
Ground penetrating radar systems generally are used to locate underground water and sewer and gas lines. But their capabilities have also been used in everything from crime scene investigations to finding lost graves and artifacts at historical sites.