It's always good to make a practice run for one of these experiments no matter how many times you've done it before. The second day after most of the people arrived we did a test run.
Below is a Global Positioning System (GPS) receiver on the hood of one of the trucks. Posing as a tripod is apparently an 'official use'. We were in a bit of a concrete canyon, so getting a good view of enough satellites was a bit of a problem at times.
We programmed up about 20 Texans and headed for Coyote Creek which was within walking distance of the hotel.
Hmmm. We didn't have creeks this fancy where I grew up in South Dakota.
We worked along the bike path that ran along the edge of the concrete creek 'bed'. Below is UNR graduate student Warren Dang planting a geophone. After planting geophones do not need to be watered, so I'm not sure what the water was for. Reftek RT-125 "Texan" recording instruments and their associated geophones were placed at regular intervals. The distance from one recorder to the next was measured using the wheel in the foreground of the picture below. The wheel has a circumference of 1 meter, and every revolution caused the small, black counter just above the wheel to "tick" and increment. Police use the same devices to make measurements during accident investigations. Not a good omen.
When the data was collected along the burm that ran next to the creek we picked everything up, moved over about 80 meters, and repeated the experiment on a burm that was lower than the other one and ran next to an irrigation canal that paralleled the creek. This was done to determine if there was any difference between the two locations because of the differences in the shapes of the burms (one taller and 'pointier', the other shorter and flatter). You can see the top of the large burm on the other side of the power poles on the left.
We downloaded the data from the 20 test Texans, and then programmed all of the instruments for the next day's recording. During programming each Texan is sent a schedule of when to start recording and when to stop. All of the Texans got the same schedule for this experiment. Once they are programmed the clock inside each Texan is synchronized to a clock that generates timing pulses using GPS signals (the one on the hood of the truck above). Once that is done the Texans are commanded to switch to their internal batteries and are ready to be deployed into the field.
We programmed in the afternoon, attached the geophones, placed each Texan into its own insulated pouch to keep the sun from baking them, and placed them all into the back of the four work vehicles so they would be ready to go in the morning. Below is Warren and UNR graduate student Hyun-Mee Park putting the Texan packages together. The insulated bags were held shut with a large binder clip.
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