Rock-slope failures in Innerdalen and Innfjorddalen, western Norway: rock-slope instabilities and rock avalanches in a changing landscape following the melt down of the Scandinavian ice sheet

• Main Author: Schleier, Markus, T.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2016
• Subjects: Massenbewegung <Geomorphologie>; ddc:551; Innerdalen; Norway; Eisschild*; Ice Sheet
• Online Access: https://opus4.kobv.de/opus4-fau/frontdoor/index/index/docId/6916; https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-69168; https://opus4.kobv.de/opus4-fau/files/6916/SchleierMarkusDissertationFAU2016.pdf

Large rock-slope failures that fail catastrophically as rock avalanches have within glacial cycles a first-order control on landscape evolution in steep mountain environments, and pose a high threat to communities. However, the identification and interpretation of complex deposits and geomorphological features caused by rock-slope failures are often difficult, and misinterpretations are not uncommon because of complex interactions between rock-slope failures and other geological processes, namely glaciation and isostasy. Such a complex geological environment can be found in the glacially overprinted mountains of western Norway. The primary aim of this study is to understand the large rock-slope failures and associated phenomena in the valleys of Innerdalen and Innfjorddalen, western Norway. The main objectives are (I) to understand the complex deposits and geomorphological features formed by multiple rock avalanches to derive their paleodynamics (i.e., runout behavior) with respect to the Scandinavian Quaternary geology following glacial melt down after the Last Glacial Maximum (LGM), and (II) to understand the geomorphological features, geological constraints and displacements of an actively moving rock-slope instability to derive its failure kinematics, deformation rate and mechanisms. The integrative approach applied in this study consists of (1) intensive field mapping including granulometric sampling, trenching, ground penetrating radar and geoelectric resistivity tomography, (2) GIS-based digital elevation model and orthophoto analyses, (3) geomechanical investigations including structural analyses by field measurements and terrestrial laser scanning (LiDAR) and kinematic feasibility tests, (4) differential global navigation satellite system displacement measurements, (5) terrestrial cosmogenic nuclide surface-exposure dating (10Be), and (6) numerical dynamic runout modeling (DAN3D). The results on spatial distribution and characteristics of surface deposits and geomorphological landforms imply hypotheses ...