What drives large-scale glacier detachments? Insights from Flat Creek glacier, St. Elias Mountains, Alaska
What drives large-scale glacier detachments? Insights from Flat Creek glacier, St. Elias Mountains, Alaska
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DOI：
10.1130/g47211.1
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发表时间：
2020-04
期刊：
影响因子：
5.8
通讯作者：
M. Jacquemart;M. Loso;Matthias Leopold;Ethan Welty;Etienne Berthier;Jasmine S.S. Hansen;John Sykes;K. Tiampo
中科院分区：
文献类型：
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作者：
M. Jacquemart;M. Loso;Matthias Leopold;Ethan Welty;Etienne Berthier;Jasmine S.S. Hansen;John Sykes;K. Tiampo
2013 年和 2015 年 CE 融化季节的高峰期发生了两次大规模冰川脱离，从阿拉斯加圣埃利亚斯山脉的 Flat Creek 冰川累计释放了 24.4–31.3 × 106 m3 的冰和岩屑物质。两次事件都产生了高度流动性和破坏性的水流，流出距离超过 11 公里。我们的研究结果表明，导致2013年首次脱离的四个主要因素是：异常高的融水输入、容易被侵蚀的冰川床、冷冰舌导致的冰下排水效率低下，以及2011年后冰内部重新分布导致的驱动应力增加。在应力状态急剧变化的情况下，冰川的稳定性此后仍然对水输入敏感，最终在2015年发生了第二次脱离。西藏阿鲁山有两个大型的分拆表明，这些分拆是由一个共同的机制引起的，由异常高的融水输入驱动。随着气温升高，融水产量增加，冰川脱离频率可能增加，这对冰川地区的风险管理有直接影响。
Two large-scale glacier detachments occurred at the peaks of the 2013 and 2015 CE melt seasons, releasing a cumulative 24.4–31.3 × 106 m3 of ice and lithic material from Flat Creek glacier, St. Elias Mountains, Alaska. Both events produced highly mobile and destructive flows with runout distances of more than 11 km. Our results suggest that four main factors led to the initial detachment in 2013: abnormally high meltwater input, an easily erodible glacier bed, inefficient subglacial drainage due to a cold-ice tongue, and increased driving stresses stemming from an internal redistribution of ice after 2011. Under a drastically altered stress regime, the stability of the glacier remained sensitive to water inputs thereafter, culminating in a second detachment in 2015. The similarities with two large detachments in the Aru mountains of Tibet suggest that these detachments were caused by a common mechanism, driven by unusually high meltwater inputs. As meltwater production increases with rising temperatures, the possible increase in frequency of glacier detachments has direct implications for risk management in glaciated regions.