Distribution and spatial analysis of rockslides failures in the Icelandic Westfjords: first results

• Published in: Géomorphologie : relief, processus, environnement
• Main Authors: Peras, Aurore, Decaulne, Armelle, Cossart, Etienne, Coquin, Julien, Mercier, Denis
• Other Authors: Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-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 (IGARUN), Université de Nantes (UN)-Université de Nantes (UN), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Université Jean Moulin - Lyon 3 (UJML), Université de Lyon, Espaces, Nature et Culture (ENeC), Université Paris-Sorbonne (UP4)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: geomorphology; paraglacial; Iceland; Deglaciation; Slopes; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; [SHS.GEO]Humanities and Social Sciences/Geography
• Online Access: https://hal.science/hal-01318152; https://doi.org/10.4000/geomorphologie.11303

International audience Rockslides are numerous in the Icelandic Westfjords. In this study, the large visible rockslides have been inventoriedin a first stage, by observation of aerial images and subsequent photo-interpretation. A total of 186 rockslides hasbeen recorded and in a second stage, their distribution has been studied, using Geographic Information Systemsand statistical methods like Kernel Density Estimator (KDE). The relief of the studied area is closely related with theglacial and interglacial periods. Rockslides are mostly concentrated close to the coast, where the relief is dominantlyshaped by glaciers exposing high slopes, while the inner part mainly constituted of plateaux is not prone to massmovements. Nevertheless, the statistical analysis does not show a strong correlation between slope gradient androckslides concentration, as the null hypothesis is not rejected. Other causes already mentioned by several authorsare consistent with the location of rockslides, such as favourable dip or mass movement occurrence in the Tertiarybasalts. These elements cannot explain the spatial distribution of rockslides in the West! ords by themselves, at aregional scale. The deglaciation pattern might provide an explanation for this spatial distribution, even withoutprecise dating. This work provides a new database where commonly claimed triggers do not provide a satisfactoryexplanation to the spatial distribution of rockslides in the Icelandic Westfjords.