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Undergraduate Research Experience in Ocean, Marine, and Polar Science 2011

"Do strain rates determine the spatial density of crevasses on the Greenland Ice Sheet?"

Mentor: Ms. Kristin Poinar

Keywords- spatial crevasse density; strain rate; tensile stengtth;Fast Fourier Transform algorithm; Greenland Ice Sheet; crevasse life span; structural glaciology;

ABSTRACT

To compare spatial crevasse density with an existing strain rate dataset, a Fast Fourier Transform (FFT) algorithm was used to create a one dimensional spatial crevasse density map from a 2.25 km^2 area on the western flank of the Greenland Ice Sheet (GIS).  Although we found a poor correlation between crevasse density and longitudinal strain rates, the correlation improved significantly when the crevasses were projected five years upstream.  This suggested that the crevasse patterns were relicts of strain rates the ice felt five years ago, and that it took five years for crevasses in the study area to open fully.  The stress required to create these crevasses, 111 ± 47 kPa, compares well to the existing body of literature on tensile strength.  The average total crevasse life span of twelve years in the study area region was found to vary greatly from that on the Worthington Glacier in Alaska, where crevasses persist for only one to two years.