Land cover characteristics in ne iceland with special reference to jökulhlaup geomorphology

Abstract

ABSTRACT Subglacial eruptions in Vatnajbkull have accounted for several jökulhlaups (glacial outburst floods) in the Northern Volcanic Zone (NVZ). These events and aeolian processes have had a considerable impact on the landscape evolution of the area. Most of this area is occupied by barren land cover; the northern margin of the barren land cover is advancing northwards, burying vegetation under wind‐blown sediment. This paper presents a land‐cover classification based on a supervised Landsat TM image classification with pre‐processing and extensive field observations. Four land cover categories were identified: (a) lava cover (34.8%); (b) barren sediment cover (39.0%); (c) vegetation (25.1%); and (d) water and snow (1.1%). The mapping of sand transport routes demonstrates that a major aeolian sand transportation pathway is situated in the western part of the study area. The sedimentary formation elongated towards the northeast is evidence of active and continuous aeolian sand transportation towards the north. Interpretation of the satellite image suggests that four main areas are affected by jökulhlaups along the Jökulsáá Fjöllum: Ásbyrgi, Grímsstaðir, Herðubreið–Möðrudalur, and the Dyngjujökull sandur. In addition, jökulhlaup‐related sediment cover (8%) in the study area, together with erosional features, are evidence of a severe and extensive jökulhlaup‐induced process of land degradation.