Planting the geophones was not just a stick-it-in-the-ground operation. Some finesse was required. The geophones have a moving part inside of them that needs to be free to move up and down (technically when the ground shakes the outside of the geophone moves up and down while the moving part in the center stays still). This required the geophones to be planted within 10 degrees of vertical. Small bubble levels were used to check each and every geophone before moving on to plant the next one. It wasn't hard to do if you didn't have to chisel out a hole for the spike. But when you did have to use the chisel it sometimes was no fun getting them level.
Photo by John Louie
There were many challenges to getting the geophones deployed where they belonged.
These stupid trains. A train, bumping along its tracks, makes a perfect source for this type of experiment. It is big, and it is noisy. The train below came through JUST as were were starting to deploy the Texans along this segment.
This train came through JUST as we were finished picking them up and getting ready to move on. Sigh.
Patched cracks in the bike path were handy to have. After we picked up the Texans all holes that we made were filled in with patching material.
The central sections of the line were long and hot and flat.
Interstate 605 roughly paralleled the San Gabriel River, so along some portions of the line we had plenty of noise to make use of.
Is there ever any flowing water in the San Gabriel River...that is not associated with flash flooding, that is?
...tick-301, tick-302, tick-303, tick-304, tick-305, tick-306, tick-307, tick-308... I'll remember that ticking sound that the wheel made for the rest of my life.
DIRECT LINKS TO PAGES:
URBAN SEISMOLOGY IN THE NAUGHTIES
FROM THE MOUNTAINS
TO THE PRAIRIES
TO THE OCEANS, WHITE WITH FOAM
MISSED FINISHING BY THAT MUCH
SIN CITY, BABY!!
THE ELECTRICITY BILL FROM HELL
DAM THE CASINOS...FULL SPEED AHEAD!
THE ROAD HOME