Institute of Earth Sciences Seminar

Magnús Tumi Gudmundsson (Institute of Earth Sciences)

Title: The jökulhlaup hazard resulting from volcanic eruptions in Öræfajökull and other steep-sided ice-covered volcanoes

Date: Friday, 16th November
Time: 12:30
Place: 3rd Floor meeting room, Askja

Abstract: Some of Iceland‘s most active volcanoes have ice cover and eruptions in these volcanoes often causes large-scale ice melting and jökulhlaups. The flooding arising because of eruptions and geothermal activity in these ice-covered volcanoes is the most common type of volcanic hazard in Iceland. This type of hazard is in no way confined to Iceland, as several ice-covered volcanoes occur in Alaska, North- and South America and elsewhere outside the tropics. Öræfajökull is the steepest and largest of the approximately cone-shaped volcanoes in Iceland. It has erupted twice since the settlement of Iceland, in 1362 and 1727. In both cases major jökulhlaups accompanied the eruptions. As a part of Gosvá, the overall volcanic hazard assessment for Iceland, a comprehensive study was carried out by the Icelandic Meteorological Office and the Institute of Earth Sciences on possible jökulhlaups resulting from eruptions in Öræfajökull. This included estimating the melting potential and the approximate sizes and propagation times of various types of jökulhlaups caused by volcanic activity, both for caldera and flank eruptions. The methodology for assessment of ice melting rates was reviewed and tested. Moreover, a methodology was developed to estimate the order of magnitude of melting and subsequent flooding resulting from pyroclastic flows in major intermediate to silicic eruptions that might occur. This methodology will be presented and its relevance for eruptions in Iceland and elsewhere assessed, including the importance of these results for possible escalation of the current unrest in Öræfajökull.

All are welcome.