Ground Penetrating Radar

We have always assumed that Pond Springs Cemetery was full of graves.  The only way to prove it was by the use of Ground Penetrating Radar (GPR).  We felt that this would be beneficial in determining the location of unmarked graves, as well as assist us in proving that markers are indeed in the correct places.

GPR is used for a lot of things, including locating buried structures and utility lines, locating rebar in concrete, defining landfills, finding contaminant plumes, and even finding buried evidence. Military uses include detection of mines, unexploded ordnance, and tunnels.  Per Wikipedia, before 1987 the Frankley Reservoir in Birmingham, England UK was leaking 540 litres of drinking water per second. In that year GPR was used successfully to isolate the leaks.

On Saturday, August 6 2011, Jacob Blust of Ground Penetrating Radar Systems, Inc. gave a demonstration by sampling a few areas of interest.

This was one of the most interesting things I have ever seen.  Basically, GPR is a non-invasive way of seeing “subsurface”, or buried, objects.  The GPR device, which sort of looks like a lawn mower, has an antenna that transmits radio waves into the ground.  Buried items reflect a signal back to the antenna.  Strong wood (not decomposed), metal, water, and concrete are good reflectors.  There are a lot of things that can create a variation in the success of GPR, such as the composition of the soil, the depth of the object, the frequency that can be attained, and of course the amount of “reflected power” that the buried object can return.

In other words, for Pond Springs Cemetery, GPR would only be successful if the deceased was buried in a reflective casket, or had a burial vault.  This narrowed us down to those buried ca. 1940 or later.  Even if buried 1940 or later, if buried in a simple pine casket, there would be no reflective data.

So, we sampled graves that spanned several decades, as well as a few areas that we were downright curious about:

1  Boatright/Henry graves.  These spanned 1886-1892.  Since we don’t really know if the markers were placed at the foot or the head, both areas were scanned.  To no one’s surprise, they yielded no results.

2  Eller/Jackson graves.  These are more modern, spanning 1923-1969.  As expected, the top of the coffin could be seen for Jeffery Jackson and for Thomas Eller (both died in the 1960s).  Mary Jackson’s coffin also reflected a little but not as strongly (buried 1923).

3  Doroteo Blanco.  Mr. Blanco was buried in 1972, and the coffin/vault should definitely reflect.  The problem is, we don’t know where he is buried !  Our only guess is that Mr. Blanco is buried under a modern piece of unmarked granite in the north section by the fence.  Scanning slowly and carefully, over several minutes, nothing reflective appeared to be buried on either side of this marker.  So, the marker is in the wrong place, or whomever it belongs to was buried in something that is now non-reflective.

4  Jesus and Lucy Garcia.  These (most interesting) results have been relayed to the descendants.

Many thanks to Jacob Blust and to Ground Penetrating Radar Systems, Inc. for their time and assistance, and for enlightening us regarding this technology and its use in old cemeteries.  If you ever need GPR done, these are the guys to call.

We’re not done with this technology yet.  And it is costly.  If interested in donating money to this project, please contact this blog.

– Suzanne

Jacob Blust of Ground Penetrating Radar, Inc. setting up the GPR

GPR Antenna

Scanning the BoatrightHenry graves

Scanning the Eller Graves

The red circle indicates the top of a coffin. The top is found at a depth of about 2 feet. Combined with the marker, which indicates a name, it can be concluded that this is the grave of Thomas Eller.

Scanning the Unknown thought to be Doroteo Blanco. It still cannot be ruled out.

Published in: on August 13, 2011 at 2:13 pm  Leave a Comment  

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