Measurements of Ice Tunnel Deformation Camp Red Rock, Greenland: Fid-Bau Portal

Measurements of Ice Tunnel Deformation Camp Red Rock, Greenland

R. E. Hilty

Detailed scientific studies on the regimen of the cliff terminus of the North Ice Cap in Greenland were initiated as a full scale project (CE Project 24) in the summer of 1955, at Camp Red Rock, Nunatarssuaq, 40 miles northeast of Thule Air Base. One of the several means of gathering information was through deformation studies in a 30-m deep horizontal tunnel excavated normal to the trend of the cliff face and aligned essentially parallel to the direction of glacier flow. During the spring and summer of 1956, a tunnel addition (referred to here as the 1956 tunnel) was extended from the side of the 1955 tunnel. The excavation in 1956 was dug to a lower level and exposed approximately 15 m sq of bouldery subglacial floor. This provided an excellent opportunity to obtain precise and detailed information on basal glacier movement as well as to study the effects on a patch of frozen ground suddenly relieved of high stresses. The tunnel walls and ceiling were instrumented with several rings of motion pegs which were surveyed with a theodolite from a system of stationary stakes. Mapping of the ice stratigraphy and other deformation studies augmented the motion survey. The primary objective of Project 24 in 1957 was to resurvey the position of the pegs in the 1956 tunnel. Compilation of data and conclusions derived constitute the basis of this report. (Author)