On this episode of "Dig Deeper,"
we're going to be using ground-penetrating radar
to try and image an area before we dig.
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We're working towards constructing what we're calling a "dead shed."
It's a shed for small, medium, and large animals
for our faunal collection, and we're hoping to start construction.
Now, with anything here at Jamestown, what we like to do,
if it involves ground disturbance, is archaeology.
And so this is no different.
We've excavated a number of holes for the footers as a first step,
and in that process, we found features.
And features are cultural activity from the past.
It can be since we became a park,
but it can also be going back to even as much as 8,000 to 9,000 years old.
There's some Native American or First Peoples material out in this area.
So, when we find those features, because we're a research organization,
we really want to know what it is we have.
And so we take pause, we back up, and in this case,
we're going to go ahead and open the area.
Well, prior to doing that, what we've decided to do is run radar.
Ground-penetrating radar is a great tool that we can use as archaeologists,
great technology in order to use radio waves to see in the ground.
Now, there's essentially two different things you can do.
One is prospecting, in which you look at a profile.
And another one's a 3-dimensional model that's generated of the space,
or what in common terms is, with ground-penetrating radar, slices.
The process is that this machine, which is a series of antennas,
sends out radio waves into the earth.
They reflect off boundaries,
so those can be ditches, pipes, graves, wells, anything that's out there,
and through a series of segments that you run across the landscape,
those lines or scans are then interpolated using a computer program
and added together at depth to give you that sort of 3D model.
So behind me, we have plywood covering up the holes
that we first excavated for the footers.
We didn't run radar in this area initially because we wanted to see
what the footers would reveal, features, if any.
We're on Statehouse Ridge, traditionally known as Statehouse Ridge,
and there had been a number of burials up on this ridge,
extending just past the museum here behind me,
so we expected to potentially see or find burials.
We've gone back, and we did a rather unique thing--
it's almost experimental-- here with the Rediscovery project,
in that we covered the holes with plywood and went ahead and ran the radar.
And what we found is that really didn't affect the radio waves.
But the process for the survey
is that you essentially set up two parallel tapes.
You want a 0 point-- you go back to the old geometry class--
you have a 0 point, and you're running on an XY grid system.
Now, in this case, because we knew there were features here,
known features, we're not prospecting, in a way.
What we decided to do was run it at half-foot intervals.
So every five inches, or five tenths of an inch, I should say,
we ran the radar machine, and what's happening
is that the radio waves are pumped into the earth.
Like I said, they're hitting off of boundaries,
and the machine is recording the time it takes
for those things to bounce off.
So here's practicing the process.
What we're going to do, Les and I here,
staff archaeologist Les Jennings and I are going to lay out a string
right on the first line, which is 0, so there'll be--
our grid here between the tapes is 20 feet,
so the 0 is the first line, so you'll end up with 41 lines throughout the process.
What we do is we put that string there,
we bring the machine and the center of the antenna
to the intersection of the string and the 0 on the tape,
and hit collect, and then we start working.
Now, what I'm seeing up on the screen here is actually the soil profiles,
both shallow and deep, and it gives me an idea.
When I see a target-- a feature, a pipe, anything in the ground--
it shows up as a parabolic target, or essentially a blip on the screen.
Again, when you add all those together, you end up seeing
walls, ditches, pipes, and things like that through the computer.
So the process is simple, just walking on the line,
making sure that the wheels turn so that it's calibrated, and then stopping.
So once I reach the end of the line,
we do our GPR surveys in a unidirectional.
So we do one, so we've got to drag the machine all the way back to the top,
and repeat the process for each half-foot interval.
So we'll continue to do this for 41 runs,
and then I'll go up and process, download and process the data.
That will be our next "Dig Deeper" video,
and I look forward to telling you guys or showing you what we found.
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