Spatial analysis and controlling factors of landslides in East Icelandic fjords

• Published in: Géomorphologie : relief, processus, environnement
• Main Authors: Portier, Emilie, Mercier, Denis, Decaulne, Armelle
• Other Authors: Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes ), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Nantes Université (Nantes Univ)-Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Humanités, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (Nantes Univ - IGARUN), Nantes Université (Nantes Univ), This research is part of the "PAraglacial Rock-slope failures dating in Iceland" programme(2022-2026) funded by the French Polar Institute Paul-Emile Victor (IPEV).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Rock-slope failure; Deglaciation; Iceland; Paraglacial; Geomorphology; [SDE]Environmental Sciences; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; Ice Sheet
• Online Access: https://hal.science/hal-04238821; https://doi.org/10.4000/geomorphologie.17634

International audience The fjords of eastern Iceland display many landslide landforms. These phenomena, visible by remote observation of satellite images and Digital Elevation Models (DEM), were inventoried then measured and analysed. A total of 290 landslides were recorded in a spreadsheet database and in a Geographic Information System (GIS). For each landslide, location, morphometry (length, width, surface area, thickness, estimated volume, etc.) data, as well as potential control variables, particularly geological (lithology, dip) or explanatory (orientation, age of deglaciation of the slope aff ected by the landslide) were recorded. These variables and their distribution were studied by spatial and statistical analysis. This study highlights a higher density of landslides in the northern part of the study area, which could be explained by past ice sheet current directions, which would have reinforced the pressure exerted on the slopes leading to the postglacial decompression phenomenon. The over-representation of west- and south-facing landslides leads to the hypothesis of climatic control: the sunnier slopes underwent more rapid deglaciation, which favoured the instability of the slopes. The data collected also suggest that the lithology (Tertiary basalts) is a control variable and the period during which the landslide area is deglaciated an explanatory variable for landslide initiation.The landslides observed are thus part of a paraglacial dynamic of slope instability after their deglaciation. Les fjords de l’est de l’Islande concentrent de nombreux glissements de terrain. Ces phénomènes visibles par observation à distance d’images satellites et d’un Modèle Numérique de Terrain (MNT) ont été inventoriés dans cette étude, puis mesurés et analysés. Au total, 290 glissements de terrain ont été recensés au sein d’une base de données sous forme de tableur et dans un Système d’Informations Géographiques (SIG). Pour chaque glissement de terrain ont été relevées sa localisation, sa morphométrie (longueur, ...