Geophysical Investigations of Unstable Mountain Slopes in Jotunheimen, Norway.
I. Lecomte, H. Juliussen, E.W. Nagel Støren, G. Sauvin, S.E. Hamran, I. Lavrientiev, D. Petrakov, S. Kutuzov and S. Tissot
Event name: Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics
Session: Poster Session 4
Publication date: 03 September 2012
Info: Extended abstract, PDF ( 981.81Kb )
Price: € 20
Studying glacial and mountain hazards is necessary as the world seems to face major climate changes, which may increase the frequency of catastrophic events, e.g., debris flows. The latter processes are well understood, but changes in their frequency and relationships to climatic variability are not. In the present study, aiming at imaging an entire debris-flow system from the release area to the depositional area, correlations of lake sediments to specific slope deposits on land are looked for by using a combined approach including geology, sediment-core analysis and geophysical surveys (ERT, GPR and seismic). Our overall goal is to create a chronology of debris-flow events from lake Leirvatnet in order to be able to compare debris-flow records with existing paleo-climatic data and evaluate the climatic impact on debris-flow frequency in a long-term perspective. Following the mapping and thickness estimate of the sediment cover on the lake bottom obtained from GPR, we are evaluating the spatial continuity of reflectors associated with sections of high debris-flow activity to relate them to debris-flow deposits on land (imaged by ERT, GPR and seismic), having a complete Holocene sedimentological history from the lake. Actual results indicate a large temporal variability in debris flows.