Surface and geometry changes during the first documented surge of Kverkjökull, central Iceland

Abstract

— Many surge-type glaciers remain unrecognised because surge events can be short-lived and are rarely captured by satellite or field data. This study reports the first documented surge of Kverkjökull, central Iceland, adding a relatively short, narrow, steep and alpine outlet glacier from the Vatnajökull ice cap to the surge-type glaciers in Iceland. The surge occurred after decades of persistent and recently accelerated terminus retreat. The surge initiated after 2008 and immediately preceded drainage of the Gengissig geothermal lake and a jökulhlaup in 2013. The surge was still in progress in 2013. It caused vertical surface displacements of up to 20 m that were most prominent in parts of the glacier >100 m thick. The magnitude of surface elevation changes, terminus advance and ice surface velocity changes probably reflect a single surge phase. Asymmetry in the response of the glacier terminus to the surge front suggests interaction with near-stagnant ice in a part of the glacier terminus but otherwise the trigger and mechanism of the Kverkjökull surge remain unexplained.