From Fieldwork to Data

For the past about two weeks, I've been again in British Columbia working on the BATHOLITHS project. My main job in this was to help deploy and pick up seismometers, for which I worked along the coastal channels and fjords near Bella Coola, travelling by boat and placing seismometers along the shore. In some places we were able to bury the instruments, as was being done on the land-based parts of the line, but good soil was often not readily available since the shore consisted mostly of cliffs and steep rocks where all we could do was find an area not too steep to scramble up and a spot on the rocks flat enough to put the geophone and Texan, and so we would plaster the geophones directly to the bedrock. This took a bit longer than burying them, and getting the plaster the right consistency could be tricky, but generally it worked all right. The days were generally long, but the work was enjoyable and the scenery beautiful. Since we hadn't surveyed the boat parts of the line in June, we also had to do the GPS for them, which I and the others based in Bella Coola did on pickup, while the other two boats based farther west in the town of Shearwater did this on deployment. Pickup went faster than deployment, despite the extra GPSing and a slow start to the first day due to weather, and we almost finished in two days instead of the allotted three, but strong wind and waves forced us to stop the second day with only 12 stations left. The third day, however, was a beautiful clear day that I was quite happy to spend out on the water, and we were able to retrieve the remaining stations quickly. In between deployment and pickup the shots were set off, and I went with most of the rest of the team staying in Bella Coola to experience one. We were standing out of sight and I don't think there was much to see anyway, but we were able to feel the ground vibrate when it went off, which was pretty cool. Aside from instrument deployment and pickup, which took about one week of two, I did some resurveying of stakes along the highway that had been mowed after we surveyed them and spent time moving equipment, putting batteries in Texans, learning to set up the instruments, transferring gps data to the computer, and at the end helped to clean up two shot holes (basically shoveling gravel and pouring bentonite in the hole to seal it).

Now that I'm back in Virginia it's time to switch gears from field work to data. It was rather sad to leave the field area for the last time, but I'm hoping the next part goes well and proves just as fascinating in its own way. Unfortunately, John, my advisor, will be away for most of the remaining time that I have on this project, but I will be working with Kai, a grad student who's also working on the project, so I won't be completely helpless if I get stuck. It seems my main goal for the next couple weeks is to pick some arrivals and start doing simple layer over a halfspace models of the crust and mantle to get an idea of moho depth and average velocities. I also need to work a bit more on getting gps data in order. Initially, I won't have the gps data to give a proper distance scale, so I'll just be working with station numbers and the approximate distance scale associated with that. Basically, I need to get an idea of the basic large-scale picture that our data show, enough to have something to report on a poster and abstract. Then, after I'm gone, others will put together the more advanced interpretation and perhaps gain insight on the questions of continental crust formation that the project is hoping to address. I also need to see about getting started on that AGU poster. Unlike most of you, I have nothing so far in the way of pretty graphs and data to display. I've spent a large part of my summer concentrating on field work, and now I need to change focus to data, so I'm hoping I'll be able to have something meaningful to show for it before I leave Virginia on August 15th.