I CAN'T TAKE THE STRAIN
My cohort in crime, the Principal Investigator (PI), for this experiment was Susan Hough from the U.S. Geological Survey office in Pasadena, California. Our first morning in Indio we loaded up our field vehicle -- the family Taurus station wagon -- and headed for the desert.
About 30 miles south of Indio, which for some reason seemed like about 300 miles when you were driving it, were several instruments designed to measure the movement of the ground. One of the larger instruments of the desert was a laser strain meter operated by Caltech which stretched across the ground for what looked to be about 500 meters.
This was, technically, a portable instrument that had been turned a couple of
different directions during its life. It was used to measure the
deformation of the earth caused by the tides. The air is removed from the
tube and a laser is turned on. The beam is split in two. One beam
travels down the length of the instrument to a mirror where it is bounced back to the
end where it originated and fed to a sensor. The other beam of light does
not travel down the tube, but is sent to the same sensor as the other beam where
they recombine. If the two beams recombine "in phase" then we have the
original laser beam back, but if the distance between the source of the laser and the mirror
at the far end of the tube changes by just millionths of an inch the light waves
of the two beams recombine "out of phase". The amount that the beams are
out of phase can be directly measured by
a change in the intensity of the recombined light beam. Simple. This
strain meter is operated by Frank K. Wyatt of Caltech. Below is
who was
doing some work on the instrument when we made it to the location of our first
station.
Running beneath and perpendicular to the instrument above is, well, another one. This one is buried.
Along the tube, seemingly in the middle of the desert, there was a hatch.
Down the hatch was an equipment room. It looked to me like a buried shipping container to me. A large vault protected from the heat, animals, and people with electricity made it the perfect place to set up our equipment.
The vacuum pump used to evacuate the air from the tube.
SHAKING IN ANTICIPATION
I CAN DO THIS
I CAN'T TAKE THE STRAIN
THE BIG FAULT
BOMBAY OASIS
OFF THE BIG FAULT
THE AMERICAN LEGION
ACTIVE VOLCANOES
ADIOS
2006-Jul-31