11 July, 2000
July 11, 2000
Work commenced at our new drill site today. The ice is significantly cleaner at this location than at the former site, and as a result, the hot water drill melted through the ice at about 2-3 times the pace. The drilling did not slow until we got to about 180 meters. At the other site, debris was obstructing the bottom of the hole by 50 meters down.
St. Olaf undergraduate Andrew Malm continued doing ice radar. His equipment has been out of commission for the past 3 days - his oscilloscope was malfunctioning. He managed to fix the problem. He plays an important role because he determines the thickness of the ice where we are drilling (as well as other spots). Ice radar works on a very simple principle. A transmitter sends out a pulse of electromagnetic radiation at a parcticular frequency, which is determined by the length of the transmitting antenna. This pulse emanates in all directions from the transmitting antenna, including down and into the glacier. This pulse also reflects off of surfaces. The most significant and obvious reflecting surface is the bedrock upon which the glacier rests. The electromagnetic wave travels downward through the ice, reflects off of the bed, and is received by a receiving antenna. Andrew interprets this return signal on an oscilloscope. Based on the time of travel, and knowing the speed of the signal, Andrew is able to determine the distance that the wave traveled. Andrew was determining a thickness of about 250 meters at our former site. At our new site, he determined an ice thickness of 1200 meters. This is pretty thick. In fact, we only have 800 meters of hose to drill with, so if the 1200 meter thickness is correct, than we will not likely drill to the glacier bed at this spot. Andrew Malm does not think that this measurement is correct. He is going to do some more radar shots tomorrow.
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