文章基本信息

标题：Crevasse initiation and history within the McMurdo Shear Zone, Antarctica
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作者：Lynn Kaluzienski ; Peter Koons ; Ellyn Enderlin 等
期刊名称：Journal of Glaciology
印刷版ISSN：0022-1430
电子版ISSN：1727-5652
出版年度：2019
卷号：65
期号：254
页码：989-999
DOI：10.1017/jog.2019.65
出版社：Cambridge University Press
摘要：While large-scale observations of intensified fracture and rifting can be observed through remote-sensing observations, understanding crevasse initiation may best be achieved with small-scale observations in which crevasses can be directly observed. Here we investigate the kinematic drivers of crevasse initiation in the McMurdo Shear Zone (MSZ), Antarctica. We delineated 420 crevasses from ~95 km of 400 MHz frequency ground-penetrating radar data and compared these data with kinematic outputs derived from remotely-sensed ice surface velocities to develop a statistical method to estimate crevasse initiation threshold strain rate values. We found the MSZ to be dominated by simple shear and that surface shear strain rates proved best for predicting crevasse features, with regions of higher shear strain rate more likely to have a greater number of crevasses. In the surveyed portion of our study region, values of shear strain rate and vorticity rate derived from the MEaSUREs2 velocity dataset range between 0.005–0.020 and 0.006–0.022 a −1 , respectively, with crevasses located at ≥0.011 and ≥0.013 a −1 . While threshold values from this study cannot be directly applied to other glacial environments, the method described here should allow for the study of shear margin evolution and assessment of localized damage and weakening processes in other locations where in situ data are available.
关键词：Crevasses; ice shelves; ground-penetrating radar; ice velocity