Week 4 June 23-29th:
This week i spent quite some time trying to learn and figure out how to do dispersion curves in Computer Programs in Seismology (CPS). I also devised a plan for the field work i would be conducting in week 5 at the FACT site at Sandia National Labs. I planned out a three day survey using five meter spacing to test out the new ATA ARS-16 rotational seismometer. Since this was a brand new sensor that was originally made to be used with a reftek, we had some modifications to make. We wanted to use it with the geode system, so i had the task of making a cable that was compatable with the geode and the new ARS-16. At first I was like me make a cable,.. Yea right, but i did and it held up pretty well. We did a couple of test and made sure everything was ready for the next week and just hoped there were no set backs.
Week 5 June 30th - 4th of July:
Well its the big week atleast thats what we thought! Melody came up from socorro because she needed "help" . Hopefully yall get that if not oh well. Anyways melody came to assist with the fieldwork and we went through a number of different ideas for our survey to generate shear waves. First we tried a 6x6 wood block. That wouldve been great for a 5 shot survey, apparently wood and sledgehammers don't get along. Plan B lets try a railroad tie. It seemed to be a better option than the 6x6. Turns out its just a heavier object to tote around and it didn't even last longer than the 6x6. So after demolishing two of our sources we moved on to the vertical hits of our survey. Its a good things those cant go wrong or can they? Well that pretty much wrapped up day 1.
Well well well the day was saved, no more destroying blocks of wood. Honeywell showed up with there new prototype Shear-Wave Seismic Generator (SWSG) and the name was given by yours truly. This SWSG is a remote controlled, truck mounted source. It has capabilities to generate shear-waves with a left or right hammer motion. It was a very unique source that has some room for improvement before it makes a big splash in future surveys. If only we would have altered some variables on our side we might have recieved some unique data sets. It also turns out you can mess up vertical shots! we changed some variables and like magic we had some pretty darn good data.
What we planned on being our last day in the field, July 3rd, well lets just say tune in next blog! So today we were going out here to do some more hammer shots with different variable adjustment to the sensor and the computer system. We also were going to clean up our survey so that equipment wouldnt get damaged over the holiday weekend. Cleaning up is so fun in the desert!
Week 6 July 8th- 12th
Well back in the office proceesing data..... looks like we are back in the field, but hey when do things ever go perfectly. So we plan to go back out there for a day and a half. first day was a half day we analyzed and thought out what exactly we were going to and what we had tools for. So this new sensor didn't come with instructions as to how they designed it to be set out. We tried setting it on the ground, setting it on a metal plate, epoxying it to the plate, and finally we tried embedding it deep in the sand. So the instrument doesnt have any spikes so we attempted to make some, but couldn't find any to fit. We eventually found some that would be just enough to hold it steady before unloading the sand into the hole we dug. So now we brought out our new source a 6x6 wood blcok with a metal plate mounted on the end. And there we have it folks, shear-wave source and we didnt destroy the wood. SUCCESS. Hey atleast thats what we thought then I smashed the trigger cable while i was swinging the hammer like i was in the homerun derby! But all hope isnt lost we still have a few good data points from when we switched cables. if only i wasn't so strong or if only they made wireless triggers! However i also had to do the vertical hammers again, but this time i had help from a local Sandian intern Jason D. So it wasn't that bad. This week i spent allot of time learning how to do ReMi in Matlab and i wrote a ton of scripts to help process all of these seismic data files. after all the analyzing we were pretty satisfied with the data we retrieved from all of the surveys we carried out. tune in next blog for more.
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