Characterization, Geometry, Temporal Evolution and Controlling Mechanisms of the Jettan Rock-Slide, Northern Norway

• Main Authors: Blikra, Lars Harald, Christiansen, Hanne Hvidtfeldt, Kristensen, Lene, Lovisolo, Mario
• Other Authors: Lollino, Giorgio, Giordan, Daniele, Crosta, Giovanni B., Corominas, Jordi, Azzam, Rafig, Wasowski, Janusz, Sciarra, Nicola
• Format: Book Part
• Language: English
• Published: Springer Science+Business Media 2015
• Subjects: Ice; Northern Norway; permafrost
• Online Access: https://curis.ku.dk/portal/da/publications/characterization-geometry-temporal-evolution-and-controlling-mechanisms-of-the-jettan-rockslide-northern-norway(16e91c78-6c37-47fd-bb9f-88356fa6356c).html; https://doi.org/10.1007/978-3-319-09057-3_40

The Jettan rockslide is an active topmost part of a large instability in paragneiss along the fjord Storfjorden in Northern Norway. It has deep back fractures in the top part with sliding planes at 45–50 m depth. The sliding planes seem to be controlled largely by SW-NE trending regional faults dipping steeply downslope towards NW. The displacements vary from about 2 cm–5 cm/year. The active movements demonstrate a systematic seasonal trend with displacements initiating during snowmelt in mid-May, decreasing during the late autumn and early winter and with low deformations until spring. The top part of the rockslide sectors has discontinuous permafrost, while sporadic permafrost is documented to exist in the open fractures in the lower parts. The seasonal changes is thought to be controlled by changing shear strength of the brecciated sliding planes due to either raising ice temperatures within the detachment zones and/or variations in water infiltration from local ice bodies to the unsaturated sliding zones.