Comment: 21:02 - 22:04 (01:02)
Source: Annenberg/CPB Resources - Earth Revealed - 9. Earthquakes
Keywords: geodimeter, "Duane Hamann", laser, "creep meter", "alignment array", Parkfield
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Our transcription: Another important component in the Parkfield effort to better understand the mechanics of faulting is the "geodimeter."
This shoots rays of laser light at 18 reflectors set up like the spokes of a wheel on the hills around Parkfield.
We put reflectors at different points around the valley, and we take measurements of those, so we keep track of how long it takes that light to go out to that reflector and come back with some sophisticated equipment and computers.
By knowing how fast the light travels and knowing how long it took it to get there and get back, we can calculate a measurement within a fraction of a millimeter on a 9 kilometer line when the conditions are really good.
This network of light is so sensitive that it can detect the slightest bending of rocks along the fault zone.
The geodimeter system covers a much broader area than either a creep meter or an alignment array survey.
They're all designed to look at the same kind of thing with different sensitivities and at different scales, so they all contribute to an understanding of the mechanics of the faulting.
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Geology School Keywords
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