Cauldron subsidence and subglacial floods

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...

Full description

Bibliographic Details
Published in:Annals of Glaciology
Main Authors: Evatt, G, Fowler, A
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:https://doi.org/10.3189/172756407782282561
https://ora.ox.ac.uk/objects/uuid:0a2e7988-a262-4ca6-b16e-c3112d54ae68
Description
Summary: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.