Competence Center Environment & Sustainability of the ETH Domain www.cces.ethz.ch

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

2. Motivation Rapid mass movements – ubiquitous and costly

3. TRAMM partnership 8 units of the ETH domainjoiningforces ETHZ – Soil and TerrestrialEnvironmentalPhysics SoilPhysics, Bioengineering WSL – MountainHydrology and Torrents HillslopeHydrology, EPFL – EnvironmentalHydraulics Laboratory Fluiddynamics, EPFL – Eng. and Env. Geology Laboratory Hydrogeology ETHZ –Geotechnical Engineering SoilMechanics, WSL – Snow and Permafrost Research SnowPhysics WSL – Avalanche, Debris flows and Rock Fall Fluiddynamics EPFL – Laboratory of SoilMechanics SoilMechanics, Externalpartners: UNI Lausanne – Institute of GeophysicsGeophysics, UNI Zürich – Department of GeographyHillslopehydrology

4. Project approach 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

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

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

7. Field experiments Field experiments Rufiberg (Arth SZ) Hydrology of a hillslope Wiler (Lötschental VS) Hydrology of a hillslope Wannengrat (Davos) Snowavalanche test site Illgraben (Susten VS) Debrisflowerosion Rüdlingen (SH) Artificiallandslidetriggering

8. TheRüdlingenexperiment presentedbySarah Springman(IGT ETHZ)

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

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

11. Results / Achievements (2) Precursors 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. van Herwijnen and Schweizer, submitted to Journal of Glaciology.

12. Results / Achievements (3) Prediction A new geomechanicalmodel accounting for spatially variable saturation was developed. 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. Results / Achievements (4) Vegetation Root reinforcement was quantified and implemented in a landslide triggering model framework. Progressive failure of root bundles Roots not only break, but also slip. Schwarz et al., 2010, Earth Surface Processes and Landform. Schwarz et al., in press, Journal of Geophysical Research Lab experiment: Pullout tests of single roots

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

15. Results / Achievements (6) Flow Inner organization of moving avalanches or debris flows is important for run-out prediction. 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. Berger et al., 2010, Water Resources Research Berger et al., in press, Journal of Geophysical Research Front of an avalanching mass enlightened by a vertical laser sheet (laboratory EPFL).

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

17. Stakeholder dialog Communication to Natural Hazard Experts in Switzerland (FAN) and local authorities

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

19. Acknowledgment The TRAMM consortium is grateful to …. • 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 ( R’Equip) 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 Wilerfür Geländearbeiten und Bereitstellung eines Bewässerungssystems beim Hangexperiment Wiler – Obre Wald • Unterallmeid-KorporationArth(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 thestaff of Monte Veritaforhostingthe TRAMM International Conference on Triggering of Rapid Mass Movements in Steep Terrain and providing a financialcontribution.