Reverse glacier motion during iceberg calving and the cause of glacial earthquakes
Reverse glacier motion during iceberg calving and the cause of glacial earthquakes
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冰山崩解过程中的冰川逆向运动和冰川地震的原因
DOI：
10.1126/science.aab0460
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发表时间：
2015
期刊：
影响因子：
56.9
通讯作者：
T. Baugé
中科院分区：
文献类型：
--
作者：
T. Murray;M. Nettles;N. Selmes;L. M. Cathles;J. Burton;T. James;S. Edwards;I. Martin;T. O'Farrell;R. Aspey;I. Rutt;T. Baugé
推动者和摇动者 当冰盖的边缘断裂并落入海中时，冰盖的其余部分会向后和向下移动，并可能遭受冰川地震。穆雷等人。研究了格陵兰岛赫尔海姆冰川的产犊。导致冰盖末端运动变化的力也会引发随之而来的地震。由于这些地震信号可以通过遍布全球的仪器检测到，因此应该可以使用这些冰川地震作为冰川崩解的指标。科学，本期第 14 页。 305 冰山崩解引起冰川地震并逆转冰盖运动。格陵兰岛近一半的质量损失是由于冰山崩解造成的，但人们对冰山崩解过程中的物理机制知之甚少，而且现场观测也很少。我们发现，格陵兰岛赫尔海姆冰川的崩解会导致冰川水平流动发生长达数分钟的逆转，并导致其终点向下偏转。反向运动是由冰山倾覆和远离冰川前沿的加速度引起的水平力造成的。向下的运动是由倾覆的冰山后面的流体动力压降引起的，这也会对固体地球产生向上的力。这些力量是冰川地震的根源，冰川地震是全球可探测到的地震事件，其正确的解释将允许对格陵兰岛和南极洲越来越多的出口冰川发生的崩解过程进行遥感。
Movers and shakers When the edge of an ice sheet breaks off and falls into the sea (calves), the remaining section of the ice sheet moves backward and down and can suffer a glacial earthquake. Murray et al. studied calving from Greenland's Helheim Glacier. The forces that cause the change in the motion of the ice sheet at its terminus also trigger the accompanying earthquakes. Because these seismic signals can be detected by instruments located all over the globe, it should be possible to use these glacial earthquakes as proxies for glacier calving. Science, this issue p. 305 Iceberg calving causes glacial earthquakes and reverses ice sheet motion. Nearly half of Greenland’s mass loss occurs through iceberg calving, but the physical mechanisms operating during calving are poorly known and in situ observations are sparse. We show that calving at Greenland’s Helheim Glacier causes a minutes-long reversal of the glacier’s horizontal flow and a downward deflection of its terminus. The reverse motion results from the horizontal force caused by iceberg capsize and acceleration away from the glacier front. The downward motion results from a hydrodynamic pressure drop behind the capsizing berg, which also causes an upward force on the solid Earth. These forces are the source of glacial earthquakes, globally detectable seismic events whose proper interpretation will allow remote sensing of calving processes occurring at increasing numbers of outlet glaciers in Greenland and Antarctica.
赫尔海姆冰川动态质量损失中的浮力弯曲和基底裂隙
影响因子：
18.3
作者：
James T
通讯作者：
James T