1. Competence Center Environment & Sustainability of the ETH Domain www.cces.ethz.ch TRAMM – Triggering of Rapid Mass Movements in Steep Terrain Manfred Stähli WSL, Mountain Hydrology and Torrents

2. Rapid mass movements – ubiquitous and costly Motivation

3. 8 units of the ETH domain joining forces WSL – Mountain Hydrology and Torrents Hillslope Hydrology, ETHZ – Soil and Terrestrial Environmental Physics Soil Physics, Bioengineering EPFL – Laboratory of Soil Mechanics Soil Mechanics, TRAMM partnership WSL – Snow and Permafrost Research Snow Physics WSL – Avalanche, Debris flows and Rock Fall Fluid dynamics ETHZ –Geotechnical Engineering Soil Mechanics, EPFL – Environmental Hydraulics Laboratory Fluid dynamics, EPFL – Eng. and Env. Geology Laboratory Hydrogeology External partners: UNI Lausanne – Institute of GeophysicsGeophysics, UNI Zürich – Department of GeographyHillslope hydrology

4. June 1, 2006; NG4 Project approach Exploit similarities of the three processes Develop concepts, models and technologies applicable to all of these rapid mass movements Perform common large-scale experiments Project approach

5. Example of a technique applicable to different rapid mass movements 5 Acoustic sensors to capture precursors Sensor development

6. Example of a model applicable to different rapid mass movements Self-Organized Criticality Model Fiber bundle model Model development Cohen et al. 2009. Water Resources Research

7. Field experiments 7 Wannengrat (Davos) Snow avalanche test site Rüdlingen (SH) Artificial landslide triggering Illgraben (Susten VS) Debris flow erosion Rufiberg (Arth SZ) Hydrology of a hillslope Wiler (Lötschental VS) Hydrology of a hillslope

8. The Rüdlingen experiment presented by Sarah Springman (IGT ETHZ)

9. Main results and achievements of TRAMM 1. Disposition 2. Precursors 3. Prediction 4. Vegetation 5. Transition 6. Flow

10. Spatial statistical models are useful for assessing the disposition of a slope to trigger shallow landslides. Von Rütte et al., submitted to Geomorphology. Analysis of landslide inventories (Rickli, WSL) Model with only geomorphic parameters Results / Achievements (1) Disposition Susceptibility map for a catchment in the Napf-region based on logistic regression. black dots = observed shallow landslides

11. van Herwijnen and Schweizer, submitted to Journal of Glaciology. Recognition of rapid mass movements with acoustic sensors is possible but not yet operational. Potential to record precursors of avalanches and landslides was demonstrated. Major problems: a) limited wave propagation; b) noise filtering Seismic signals associated with the release of a natural snow slab avalanche. Results / Achievements (2) Precursors

12. A new geomechanical model accounting for spatially variable saturation was developed. Results / Achievements (3) Prediction 2-dimensional finite element discretization deformation = f(soil water content and pore pressure) Localization of shear strains during infiltration (case study: Rüdlingen) Nuth and Laloui, 2008, Computers and Geotechnics.

13. Root reinforcement was quantified and implemented in a landslide triggering model framework. Results / Achievements (4) Vegetation Lab experiment: Pullout tests of single roots Schwarz et al., 2010, Earth Surface Processes and Landform. Schwarz et al., in press, Journal of Geophysical Research Progressive failure of root bundles Roots not only break, but also slip.

14. The progressive failure of a hillslope can be reproduced with a combination of SOC and fiber bundle model. Results / Achievements (5) Transition Failure patterns simulated with SOC model. Cohen et al., 2009, Water Resources Research Lehmann et al. in prep. Water Resources Research Combination of randomness and known hydro-mechanical controls. Not a threshold phenomenon, but a propagation of a local failure

15. Berger et al., 2010, Water Resources Research Berger et al., in press, Journal of Geophysical Research Inner organization of moving avalanches or debris flows is important for run-out prediction. Results / Achievements (6) Flow Front of an avalanching mass enlightened by a vertical laser sheet (laboratory EPFL). Sediment entrainment of debris flows quantified. Critical role of the solid concentration for the stability of flow motion Erosion (red) and deposition (blue) areas of a debris flow (1 July 2008) in the Illgraben.

16. Monte Verità-conference (April 2010) 16 International exchange

17. Communication to Natural Hazard Experts in Switzerland (FAN) and local authorities June 1, 2006; NG Stakeholder dialog

18. Synthesis report Dissemination Main achievements 2-page summary of sub-projects For natural hazard experts and decision makers

19. Acknowledgment The Competence Centre Environment and Sustainability (CCES) of the ETH Domain for financial support and promotion of the TRAMM project The Swiss National Foundation (SNF) for funding of grants No. 206021-117407 / 1 ( REquip) and 200021- 122299 / 1 (Dissertation Jonas Von Rütte) Gemeinde Rüdlingen (Gemeindepräsidentin K. Leutenegger) für die Bewilligung und grosse Unterstützung bei der Durchführung des Hangrutsch-Experiments Rüdlingen und Gemeinde Buchberg für die Hilfe bei der Wassserversorgung (Burger-)Gemeinde Wiler (Lötschental, VS; Gemeindepräsident: B. Rieder) für die Bewilligung und Unterstützung bei der Durchführung des Hang-Experiments Wiler – Obre Wald. Forstdienst Wiler für Geländearbeiten und Bereitstellung eines Bewässerungssystems beim Hangexperiment Wiler – Obre Wald Unterallmeid-Korporation Arth (Herr K. Weber) und Herr Kenel (Rufiberg) für die Bewilligung und Unterstützung bei der Durchführung des Hangexperiments Rufiberg. FAN – Fachleute Naturgefahren Schweiz – für die Möglichkeit, Ergebnisse aus dem Projekt in der FAN- Agenda zu publizieren Geobrugg AG, Romanshorn, für die Bereitstellung eines Sicherheitsnetzes beim Rüdlingen-Experiment Centro Stefano Franscini and the staff of Monte Verita for hosting the TRAMM International Conference on Triggering of Rapid Mass Movements in Steep Terrain and providing a financial contribution. The TRAMM consortium is grateful to ….