GDT is an
imaging technology pioneered by
Alan Witten, a
researcher from the
Oak Ridge National Laboratory.
A GDT
device essentially consists of a
shotgun aimed at the
ground, several
microphones placed in surrounding
bore holes, and a laptop
computer for real-time
data analysis.
By mapping
sound waves generated by the shotgun
blasts, 3d
images of the underlying area can be generated.
This
technology was first put to use in
1988. Witten used it on the sandstone cliffs of
New Mexico, uncovering a
dinosaur now labeled
Seismosaurus.
Since then, Witten's GDT has been used for various
paleontology and
archaeology projects, including the
excavation of a
lost city under the
desert in
Isreal.
Altogether
impressive, considering the technology was intended to locate
underground sludge.