Morino2021_Article_TheImpactOfGround-iceThawOnLan.pdf (11.6 MB)
Download fileThe impact of ground-ice thaw on landslide geomorphology and dynamics: two case studies in northern Iceland
journal contribution
posted on 11.05.2021, 08:43 authored by C Morino, SJ Conway, MR Balme, JK Helgason, Þ Sæmundsson, C Jordan, John HillierJohn Hillier, T ArglesAbstract. As consequence of ongoing climate change, permafrost degradation is thought to be increasingly affecting slope
stability in periglacial environments. This is of growing concern in Iceland, where in the last decade permafrost degradation
has been identified among the triggering factors of landslides. The role of ground ice in conditioning the morphology and
dynamics of landslides involving loose deposits is poorly understood. We show the geomorphological impact of the Móafellshyrna and Árnesfjall landslides that recently occurred in ice-cemented talus deposits in northern Iceland. Using field
and aerial remote sensing measurements of the morphological and morphometric characteristics of the landslides, we assess
the influence of thawing ground ice on their propagation style and dynamics. The two mass movements are complex and are
similar to rock- and debris-ice avalanches, changing trajectory and exhibiting evidence of transitioning their style of motion
from a dry granular mass to a debris flow-like movement via multiple pulses. We infer that the thawing of ground ice together with the entrainment of saturated material provided the extra fluid causing this change in dynamics. The hazardous
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consequences of permafrost degradation will increasingly affect mountain regions in the future, and ground-ice thaw in steep
terrain is a particularly hazardous phenomenon, as it may induce unexpected long-runout failures and can cause slope
instability to continue even after the landslide event. Our study expands our knowledge of how landslides develop in unstable
ice-cemented deposits, and will aid assessment and mitigation of the hazard that they pose in Iceland and other mountainous periglacial areas.
Funding
British Geological Survey University Funding Initiative Studentship (GA/14S/024, Ref: 284)
Agence Nationale de la Recherche in the framework of the project ANR-19-CE01-0010 PERMOLARDS
Région Pays de la Loire, project GeoPlaNet (convention N° 2016-10982)
History
School
- Social Sciences and Humanities
Department
- Geography and Environment