Jökulhlaup-influenced Topography and Geomorphology at Kverkfjöll, Iceland

Abstract

Please click here to download the map associated with this article. High magnitude jökulhlaups (glacial outburst floods) are known to have drained along the Jökulsá á Fjöllum river from the northern margin of Vatnajökull, Iceland during the Holocene. However, little is known of the number, age, source and flow characteristics of these jökulhlaups. Ongoing research therefore seeks to quantitatively analyse jökulhlaups from Kverkfjöll, which is a discrete source of meltwater into the Jökulsá á Fjöllum. To this end a high-resolution digital elevation model was produced and extensive geomorphological mapping and sedimentary analyses were accomplished in the field. The digital elevation model was produced by digital photogrammetry of scanned aerial photographs with the ERDAS Imagine Orthobase software. Processing incorporated twenty-nine ground control points, which were surveyed with a differential global positioning system. Ground control points allow photographic distortion to be removed and the elevation model to be located on the Earth's surface. A DEM with 10 m horizontal resolution was resampled from a 5 m horizontal resolution extraction. The DEM has sub-metre vertical accuracy. The DEM is substantially more detailed than presently available topographic maps and is therefore of interest for a whole range of recreational and scientific purposes. This research has identified geomorphological surfaces that distinguish at least three jökulhlaups from Kverkfjöll during the Holocene. These jökulhlaups routed into the Jökulsá á Fjöllum. Ongoing research has also sought to examine flow characteristics of jökulhlaups through Kverkfjallarani and to compare calculations of spatial and temporal hydraulics to maps of geomorphological and sedimentological jökulhlaup products.