MORPHOSTRUCTURAL ANALYSIS OF AN ALPINE DEBRIS FLOWS CATCHMENT: IMPLICATION FOR DEBRIS SUPPLY — IJEGE
 
 
You are here: Focus and scope Issues from 2005 to 2017 5th International Conference on Debris-Flow Hazards "Mitigation, Mechanics, Prediction and Assessment" Topic 1 - Debris-flow Occurrence and Initiation MORPHOSTRUCTURAL ANALYSIS OF AN ALPINE DEBRIS FLOWS CATCHMENT: IMPLICATION FOR DEBRIS SUPPLY
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MORPHOSTRUCTURAL ANALYSIS OF AN ALPINE DEBRIS FLOWS CATCHMENT: IMPLICATION FOR DEBRIS SUPPLY



Abstract:
Rock slope instabilities are implicitly linked to the supply of sediment and debris recharging channels prone to debris flow. Hence, the incorporation of bedrock structure and terrain morphology can be relevant in the analysis of sediment budget and debris flow hazard assessment. Here, the mode of debris production of the Manival catchment (northern French Alps) is documented by the study of its morphostructural aspects extracted from high resolution DEM. Terrain implication in the process of debris supply is evaluated by: a) A systematic classification of the major morphological units based on the slope gradient that enables a spatial analysis of zones of debris production and deposition. b) A detailed structural analysis performed on DEM in order to identify potential unstable slopes. c) An analysis of the gullies orientation that informs in term of structural control of the sources zones. d) Localisation of high density joints sets that document about whether sources of continuous debris production are controlled by the structural setting of the catchment. These DEM-based indicators can be used as proxies for assessing the influences of the current topography and enable to quantify a degree of susceptibility to mass wasting and hillslope erosion activity. This present contribution suggests some directions for characterizing sediment flux dynamic in small alpine catchment.

Authors:
Alexandre Loye - Institute of Geomatics and Risk Analysis, University of Lausanne, Switzerland
Michel Jaboyedoff - Institute of Geomatics and Risk Analysis, University of Lausanne, Switzerland
Andrea Pedrazzini - Institute of Geomatics and Risk Analysis, University of Lausanne, Switzerland
J. Theule - Institute of Geomatics and Risk Analysis, University of Lausanne, Switzerland
Frederic Liébault - Cemagref, Unité de Recherche Erosion Torrentielle, Neige et Avalanches, Grenoble, France
Richard Metzger - Institute of Geomatics and Risk Analysis, University of Lausanne, Switzerland
Keywords
Sediment budget, erosion, structural control, debris flow hazard assessment on DEM
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