Modelling of subaerial jökulhlaups in Iceland

doi:10.1017/CBO9780511635632.014

14 - Modelling of subaerial jökulhlaups in Iceland

Published online by Cambridge University Press: 04 May 2010

Snorri Páll Kjaran ,

Sigurður Lárus Hólm ,

Eric M. Myer ,

Tómas Jóhannesson and

Edited by

Paul A. Carling and

Devon M. Burr: Affiliation:
University of Tennessee
Paul A. Carling: Affiliation:
University of Southampton
Victor R. Baker: Affiliation:
University of Arizona

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Summary

The flow of subaerial jökulhlaups is in principle similar to other subaerial water floods, such as dam-break floods, although some jökulhlaups may carry so much suspended sediment and ice fragments that they would be more appropriately described as rapidly flowing debris flows or lahars. Many subaerial jökulhlaups start out as subglacial floods and propagate as subaerial floods below an outlet at the glacier terminus. Other jökulhlaups, in particular many outburst floods caused by volcanic eruptions, lead to a partial or almost complete breakup of the glacier along the flow path and become subaerial after flowing only a short distance subglacially. The dynamics of the subaerial part of jökulhlaups differs fundamentally from the dynamics of the part of the flood that flows along the bed of the glacier or ice cap. The estimated discharge of jökulhlaups observed at many locations in Iceland during the twentieth century ranges from 0.1 to 300 × 103 m3 s−1 and prehistoric jökulhlaups have been estimated to have reached on the order of 106 m3 s−1. The subaerial propagation of jökulhlaups can cause widespread damage to buildings, roads, communication lines and farmland. Two-dimensional numerical modelling, based on a depth-integrated formulation of the dynamics of shallow water flow, has been used to study the flow of subaerial jökulhlaups at four locations in Iceland, two of which are described in this chapter. Model results include estimates of travel times, the most probable flood routes and the extent of lowland areas that might be flooded.

Type: Chapter
Information: Megaflooding on Earth and Mars , pp. 265 - 272

DOI: https://doi.org/10.1017/CBO9780511635632.014 [Opens in a new window]

Publisher: Cambridge University Press

Print publication year: 2009

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