U.S. Scientists End Seismic Traverse

Press, Volume CII, Issue 30042, 29 January 1963, Page 14

U.S. Scientists End Seismic Traverse

Three large snocats arrived at the United States South Pole station at the week-end, to complete one of the most successful seismic traverses yet held on the continental plateau. Led by Mr E. S. Robinson, of the University of Wisconsin, the expedition made 25 seismic reflection shots to measure the thickness of the ice and three long refraction shots to measure thickness and composition of the rock layers beneath the ice. In the course of the traverse, the scientists measured an ice thickness ot 9315 ft near the South Pole This year’s traverse, which began and ended at the South Pole, was made possible through a grant from the National Science Foundation. The eight-man expedition travelled more than 950 miles in 48 days. Seismic studies were made at each of the 25 major scientific stataions on the route The scientists detonated a charge in a hole drilled in the ice and measured the time for the sound waves to travel through the ice. bounce off the underlying rock, and return to the surface.

In toe long refraction toots, a large charge was detonated, and sound waves picked up on a network of detectors from nine to 12

miles away. A final long refraction shot, encompassing 16 miles, is now being set up near the South Pole station.

Gravity and magnetic studies were also undertaken during the traverse, and ice cores were brought up by a special drill mounted on one end of the vehicles. These will be sent to the University of Wisconsin and Ohio State University for geological study. The expedition was conducted in two sections, with a return to the South Pole for fuel dividing them The track ot each leg was a triangular - shaped traverse the first in the direction of the Queen Maud range, and the second towards the Horlick mountains.

The travelling surface was consistently bad. with three to four foot high sastrugi making the going very rough These wave-like billows in the ice gave the vehicles a constant pounding and a lot of time was spent in making repairs. For Mr Robinson, this was his third trip to the Antarctic. and the fourth traverse in which he has taken part In 1957-58 be spent 115 days on a traverse-on the Ross ire-shelf and was on toe shelf again for 31 days tn 1960 During toe 1980-81 season he was also on toe McMurdo-

South Pole traverse for 65 days. He has now traversed more than 4500 miles across various Darts of the continent

5 The analysis of the data [ collected during the latest ’ traverse will be carried out in the United States.