Forensic Geophysics with 2D Borehole Radar

Watching TV dramas we are familiar with all the latest forensic technology in collecting and evaluating evidence in the pursuit of solving a crime. But what if the evidence is buried and not readily visible?  Forensic geophysics is the application of geophysical techniques such as radar for detecting objects hidden underground.  

There are various geophysical techniques for forensic investigations in which the targets are buried and have different dimensions from weapons to metal barrels. Geophysical methods like 2D BHR have the ability to aid the search and the recovery of such targets. In the subsurface when there is a contrast of physical properties between the target and the material in which it is buried, it is possible to isolate and precisely observe the buried object.  

What if the buried objects are under a concrete slab or under a building? Dense urban environments present different challenges than open unobstructed areas where GPR is most often used.  

Recently, we were asked to find two large metal objects. Although these objects were unexploded ordnances it could have easily been two metal barrels or drums.  

The  image to the left depicts a radargram showing reflections of two shallow bombs within a radius of 4.0-4.5 meters from the borehole. The vertical axis of the radargram represents the depth. The horizontal axis represents the distance. The depth below the surface is 4.0 meters well beyond the range of traditional GPR. The objects are +/- 2.75 meters from the borehole. The bombs had a 8” diameter and a length of 36 inches. The soil conditions were clayey soil with background minerals present.  

The 2D BHR tool can be used in various shallow and deep underground applications where surface radar operation is not feasible.  It is a simple, safe and clear way to receive data about the subsurface.

Please contact T&A Survey to receive a quote or for additional information.