Spatial distribution of erosion and deposition during a glacier surge: Bruarjokull, Iceland

Time-series of digital elevation models (DEMs) of the forefield of the Bruarjokull surge-type glacier in Iceland were used to quantify the volume of material that was mobilized by the 1963-1964 surge. The DEMs were produced by stereophotogrammetry on aerial photographs from before the surge (1961) and after (1988 and 2003). The analysis was performed on two DEMs of Difference (DoDs), i.e., a 1961-2003 DoD documenting the impact of the surge and a 1988-2003 DoD documenting the post-surge modification of the juvenile surging glacier landsystem. Combined with a digital geomorphological map, the DoDs allow us to quantify the impact of the surge on a landsystem scale down to individual landforms. A total of 34.2 +/- 11.3 x 10(6) m(3) of material was mobilized in the 30.7-km(2) study area as a result of the most recent surge event Of these, 17.4 +/- 6.6 x 10(6) m(3) of the material were eroded and 16.8 +/- 4.7 x 10(6) m(3) were deposited. More than half of the deposited volume was ice-cored landforms. This study demonstrates that although the total mobilized mass volume is high, the net volume gain of ice and sediment deposited as landforms in the forefield caused by the surge is low. Furthermore, deposition of new dead-ice from the 1963-1964 surge constitutes as much as 64% of the volume gain in the forefield. The 1988-2003 DoD is used to quantify the melt-out of this dead-ice and other paraglacial modification of the recently deglaciated forefield of Bruarjokull. (C) 2015 Elsevier B.V. All rights reserved