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Reconstruction of the largest Holocene jökulhlaup within Jökulsá á Fjöllum, NE Iceland

Lookup NU author(s): Professor Andrew RussellORCiD

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Abstract

Glacial outburst floods (jökulhlaups) have a significant role for landscape evolution in NE Iceland. A number of jökulhlaups have routed from the northern margin of Vatnajökull during the Holocene. In this study, reconstruction of the largest Holocene jökulhlaup along Jökulsá á Fjöllum, NE Iceland was undertaken using the HEC-RAS hydraulic modelling and HEC-GeoRAS flood mapping techniques with a Digital Elevation Model (DEM) derived from ERS-InSAR data and field-based wash limit evidence. The largest jökulhlaup produced extensive erosional and depositional landforms across an inundated area of 1390 km2 and is calculated to have had a peak discharge of 0.9×106 m3 s−1. Power per unit area within this jökulhlaup varied from 6 to 46,000 W m−2. Jökulhlaup hydraulics are related to geomorphogical evidence at three key sites: in Vaðalda, Upptyppingar and Möðrudalur sub-areas in order to explain the abrupt spatial variation of the flood characteristics on a regional scale and to relate erosional and depositional features to spatial variations in jökulhlaup hydraulics. These process-form relationships of the largest jökulhlaup along the Jökulsá á Fjöllum are compared with large outburst floods elsewhere. The largest Jökulsá á Fjöllum jökulhlaup had a factor of 20 times smaller discharge and a factor of 20 times lower power per unit area than Altai palaeoflood—the largest known flood on the Earth.

Publication metadata

Author(s): Alho P, Russell AJ, Carrivick JL, Käyhkö J

Publication type: Article

Publication status: Published

Journal: Quaternary Science Reviews

Year: 2005

Volume: 24

Issue: 22

Pages: 2319-2334

Print publication date: 27/06/2005

ISSN (print): 0277-3791

ISSN (electronic): 1873-457X

URL: http://dx.doi.org/10.1016/j.quascirev.2004.11.021

DOI: 10.1016/j.quascirev.2004.11.021

Notes: Conference proceedings: XVI INQUA Congress held in Reno, NV, August 2003. Poster session 42. Special issue of Quaternary Science Reviews: Reassessing the role of meltwater processes during Quaternary glaciations

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