Name: Tim Bartholomaus
Date: December 20, 2008 (only 5 days 'til Christmas!)
Location: WAIS Divide Galley
Temperature: -26 °C (-15 °F)
Wind speed: 8 km/h (5 mp/h)
Visibility: ~5 miles (8 km)
Wind direction: From the north
Precipitation: Light snow
Breakfast: Fried grits, "fancy fruit" muffins
Lunch: Pizza of many different varieties
Supper: Flank steak, chicken and veggie noodle soup, baked potato wedges, pastry with fruit, chocolate cupcakes
Photo notes: DSCN1088.jpg Me in front of our nearly complete seismic stations. The solar panel tower is behind my head. Largely buried behind the solar panel tower is the battery and electronics box. The top of one of the seismometer shields is visible within an excavation at the left of the photo.
IMGP1199.jpg A Nansen sled, hitched to the back of a snowmobile. One corner of the solar panel tower is visible at left.
Tim here; chiming back in. Yesterday, as John Fegyveresi wrote, he and Bob Greschke hauled equipment 5 miles out from camp in order to install an extremely precise instrument to measure shaking at the ice surface. Today, I helped Bob, who works for a science support organization known as PASSCAL, set up this instrument, known as a seismometer. The reason for this unusual mission, unrelated to my traditional duties logging and measuring the deep ice core pulled from the interior of the West Antarctic Ice Sheet, is the specific flavor of my personal research interests. While I'm not in school at the moment, in the fall of '09 I hope to start a Ph.D. in glaciology, with a particular focus on the mechanics and geophysics of how and why glaciers and ice sheets move. In contrast, most of my peers are more interested in paleoclimate and what the chemistry of the ice and air bubbles within the core tells us about past, present and future climate.
Bob Greschke is working on a large-scale project called Pole Net that will establish an array of seismometers across Antarctica to identify and analyze earthquakes from around the world. When he got into camp on the LC-130 flight a few days ago and asked our crew "little boss," Anais, for an assistant, she correctly suspected that I'd be interested in this geophysics assignment. So we loaded up a sled with over 500 lbs of batteries, hitched it to a ski-doo, and drove way off past the end of the ski runway at camp. Once camp, with its 40-odd buildings and tents was nothing more than a smudge on the horizon, we stopped at the equipment cache laid out the day before. At this point, we were surrounded by the expanse of the great flat white (as surrounded as one can be by emptiness). Again, I have to reiterate how stunning it is to be out there. I think Antarctica has actually increased my appreciation for the high plains of the U.S. and other wide-open landscapes. There really is a simple, austere beauty to these places.
The work that Bob and I did out at his WAIS Divide seismic station was rather simple and compares well to assembling a very large erector set then threading it together with power and data cables. First, we bolted together the 5-foot-on-a-side tripod of solar panels and guyed it out to anchors buried in the snow. Then we quarried (with a wood saw and shovel) two large holes into the snow surface into which the battery and electronics box and the seismometer shield could be placed. Into the battery and electronics box, we placed ten large-capacity batteries. Although now, during the summer, there's plenty of sunlight feeding the solar panels to easily keep the batteries topped off, the set-up we installed will be sufficient to keep the seismometer powered through 5 months of continuous darkness. Finally, we leveled and connected the seismometer, and covered it with a series of shields to reduce the impact of air currents that could push ever-so-subtly, but measurably, against the sensor and also protect it from the weather.
When all was set, I stood on the snow 15 feet from the seismometer and swung my body weight forward- pushing my feet against the snow. On a little hand-held computer, Bob and I could then watch as the sensor recorded the shake in three directions: North-South, East-West, and up-down. This was my first time working with a seismometer and, as seismic methods are becoming increasingly used in glaciologic applications, I was happy to have been able to help out with it and extremely impressed with the technology.
One of the things that struck me while I was out installing this high-precision digital instrument was the long history of Antarctic exploration, and how the equipment we use reflects this. For one, we drove out to this remote instrument installation on a small snowmobile that had been painstakingly maintained by U.S. Antarctic Program staff since the 1970s. Although seismometers have been in use since at least the early portion of the 20th century, ours was equipped with a satellite phone antenna so that it could communicate with researchers in the U.S. But the most fascinating pieces of still-active history are the sleds used to tow equipment and people behind snowmobiles. These sleds are named for Nansen, the Norwegian explorer who nearly became the first person to reach the North Pole while using them in 1893. In fact, I'm fairly convinced that the sled we used today may well be over 100 years old, although the sinew, leather, and rope lashings are still present and in good repair. The wood frame is incredibly solid. Despite the abuse these sleds see in doing fieldwork, they are exceptionally well preserved- largely due to the cold and dryness of Antarctica. I marveled at the expeditions this sled must have seen. How much of the continent has it traveled? Which pioneering glaciologists has it met? And what would these pioneering explorers and scientists think if they could see the work we do on the continent now?
On Monday, we start our 24-hr shift rotation in the drilling and core processing arches. I'll be on the second shift with Spruce- working from 3 until 11 pm. I'm really excited- I think we drilled about another 15 meters today, but now is when we're really going to start making serious progress. I kind of like the idea that, even while I'm sleeping, or eating meals, or blogging, we'll be advancing the borehole, and getting more ice core. It's very satisfying to be part of such a motivated, hard-working and productive team.