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Comment: 05:00 - 06:15 (01:15)
Source: Annenberg/CPB Resources - Earth Revealed 26. Living With Earth, Part II
Keywords: "Stephen Scott", "seismic wave", oil, "Vibra-seis truck", drilling, "electronic receiver", geophone, "reflection seismogram", subsurface, image
Our transcription: Seismic waves are artificially generated above potential oil-bearing rocks.
We have a truck called a Vibra-seis truck that actually shakes the ground.
The Vibra-seis truck would shake the ground in an up and down fashion much like a jackhammer on a construction site shakes the ground.
We may drill a hole 5-foot or 200-foot down into the ground and load it with 5 to 20 pounds of dynamite and set dynamite off creating that shock wave that we need.
These shock waves are detected by electronic receivers known as "geophones."
The geophones are laid out in a line or a grid pattern over the area to be mapped.
The information recorded by the geophones is processed by a computer which, in turn, generates a reflection seismogram.
And what you see on this reflection seismogram is a series of reflections.
And those are occurring where that source that goes down through the Earth, that shock-wave, bounces off of the subsurface rocks and comes back to the surface and is recorded at the geophones.
So we see images of the subsurface.
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