Spatio-temporal variability in debris-flow activity: a tree-ring study at Geisstriftbach (Swiss Alps) extending back to AD 1736

Article Article scientifique Article Spatio-temporal variability in debris-flow activity: a tree-ring study at Geisstriftbach (Swiss Alps) extending back to AD 1736 eng 2010 author Stoffel Markus 131626 author Schneuwly-Bollschweiler Michelle 692882 author Widmer Susanne 506157 author Sorg Annina 735775 283-292 10.1007/s00015-010-0014-4 1661-8726 http://link.springer.com/10.1007/s00015-010-0014-4 Past debris-flow activity on the forested cone of the Geisstriftbach torrent (St. Niklaus, Valais, Swiss Alps) was assessed from growth disturbances in old conifer trees, providing a much improved record of past events. The study of 633 tree-ring sequences sampled from 252 European larch (Larix decidua Mill.), Norway spruce (Picea abies (L.) Karst.) and Silver birch (Betula pendula Roth.) trees allowed reconstruction of 53 debris-flow events since AD 1736. The spatial analysis of trees affected during particular events on the geomorphic map allowed for a spatial representation of individual events and a reconstruction of four flow patterns. Based on our results and Siegfried maps, we believe that before the formation of a dogleg near the cone apex in the late 1890s, debris flows preferentially used the channels located in the west-southwestern part of the Geisstriftbach cone. This study contributes to our understanding of debris-flow processes on cones and provides an example of how dendrogeomorphic techniques may help in the reconstruction and understanding of debris flows in Alpine areas. Dewey 333.7-333.9 Open Access - Licence nationale Springer 18 Institut des sciences de l'environnement 0DB false 915 Climatic Change and Climate Impacts Swiss Journal of Geosciences 103 2 2878ceb9-9519-4aba-8074-b9e8c69b9d67 Article (Published version) Public Stoffel2010_Article_Spatio-temporalVariabilityInDe.pdf 934874 application/pdf openAccess Centres et instituts / Institut des sciences de l'environnement

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Spatio-temporal variability in debris-flow activity: a tree-ring study at Geisstriftbach (Swiss Alps) extending back to AD 1736	Swiss Journal of Geosciences			2010	329	138

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Widmer, Susanne