Ice tectonic deformation during the rapid in situ drainage of a supraglacial lake on the Greenland Ice Sheet
Ice tectonic deformation during the rapid in situ drainage of a supraglacial lake on the Greenland Ice Sheet
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DOI：
10.5194/tc-7-129-2013
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发表时间：
2013-01-01
期刊：
影响因子：
5.2
通讯作者：
Box, J. E.
中科院分区：
文献类型：
--
作者：
Doyle, S. H.;Hubbard, A. L.;Box, J. E.
我们提供了详细的记录湖泊流量，冰的运动和被动地震捕捉行为和过程之前，期间和之后的快速排水类似4公里（2）的冰上湖通过1.1公里厚的冰在格陵兰冰盖的西部边缘。3300 m（3）s（-1）的峰值流量与最大垂直抬升速率一致，表明地表水进入冰床界面，导致广泛的水力分离和增强的基底运动。位于湖周围的四个全球定位系统（GPS）接收器的差动记录了湖泊排水所通过的裂缝的打开和关闭。我们假设，大部分的放电发生通过一个类似的3公里长的裂缝，其润湿长度的平均峰值宽度为0.4米。我们认为，裂缝的三分之一规模的长度允许快速排放，以实现合理的水速度与亚米裂缝宽度相结合。这些观察增加了目前有限的知识，在原位冰上湖排水事件，迅速提供大量的水的冰床界面。
We present detailed records of lake discharge, ice motion and passive seismicity capturing the behaviour and processes preceding, during and following the rapid drainage of a similar to 4 km(2) supraglacial lake through 1.1-km-thick ice on the western margin of the Greenland Ice Sheet. Peak discharge of 3300 m(3) s(-1) coincident with maximal rates of vertical uplift indicates that surface water accessed the ice-bed interface causing widespread hydraulic separation and enhanced basal motion. The differential motion of four global positioning system (GPS) receivers located around the lake record the opening and closure of the fractures through which the lake drained. We hypothesise that the majority of discharge occurred through a similar to 3-km-long fracture with a peak width averaged across its wetted length of similar to 0.4 m. We argue that the fracture's kilometre-scale length allowed rapid discharge to be achieved by combining reasonable water velocities with sub-metre fracture widths. These observations add to the currently limited knowledge of in situ supraglacial lake drainage events, which rapidly deliver large volumes of water to the ice-bed interface.