Cauldron subsidence and subglacial floods
Cauldron subsidence and subglacial floods
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大锅沉降和冰下洪水
DOI：
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发表时间：
2007
影响因子：
2.9
通讯作者：
Andrew C. Fowler
中科院分区：
文献类型：
--
作者：
G. Evatt;Andrew C. Fowler
摘要冰釜是指当冰下湖泊干涸时，特别是当冰下火山爆发时，在冰盖表面形成的凹陷。这种大锅的著名例子出现在冰岛Vatnajökull冰帽的表面。更一般地说，当一个冰下湖泊在jökulhlaup期间清空时，大锅就会形成。冰面下沉的速度与冰下水从湖中流出的速度有关。我们将经典梁理论的粘性版本应用于冰盖，以确定沉降速率与洪水流量之间的关系。我们利用这些结果来推断大锅中的环断裂间距、对洪水流量动力学的影响以及南极冰盖沉降事件的可能性质。
Abstract Ice cauldrons are depressions which form at the surface of ice sheets when an underlying subglacial lake empties, in particular when subglacial volcanic eruptions occur. Notable examples of such cauldrons occur on the surface of the Vatnajökull ice cap in Iceland. More generally, cauldrons will form when a subglacial lake empties during a jökulhlaup. The rate of subsidence of the ice surface is related to the rate at which the subglacial water empties from the lake. We use a viscous version of classical beam theory applied to the ice sheet to determine the relation between the subsidence rate and flood discharge. We use the results to make inferences concerning ring fracture spacings in cauldrons, the consequent effect on flood discharge dynamics and the likely nature of subsidence events in the Antarctic Ice Sheet.