Department of Geography 

Rock-ice avalanches: a systematic investigation of the
influence of ice
The hypothesis of this project (my PhD project) is, that ice can significantly reduce the friction of mass movements – either as a main component of the moving material itself or as a low friction surface (glacier). During the last decades, several events have shown the disastrous potential of rock-ice avalanches if they occur close to populated regions. In terms of the ongoing climate change and the supposed intensification of mass movement processes in mountainous regions, the question of the possible consequences of a large rock-ice avalanche close to populated areas as in the European Alps raises.
The study consists of 3 main components: (1) numerical modelling of large rock-ice avalanches, (2) physical modelling of rock-ice mixtures in a vertically rotating drum in Vienna and Berkeley, and (3) event documentation of the most important large rock-ice avalanches around the world. The goal is to draw a coherent picture of the dynamic characteristics of such events and to quantify the effect of ice on the friction and hence on the runout distance. In future, such knowledge can serve in numerical modelling for detailed case study analysis and scenario building in potentially endangered areas, which in turn can be used to update specific parts in hazard maps.

Glacial Lake Outburst Flood Risk Assessment and Modeling in Tajikistan (TajHaz)

In 2002, a glacial lake outburst flood (GLOF) caused a debris flow reaching the village of Dasht in southwestern Tajikistan and caused several victims. The TajHaz-project was founded to assess the risk of GLOFs from recently developed glacial lakes in the high mountain environment of Tajikistan. Within the TajHaz project, the Physical Geography Division of the Department of Geography Zurich (GIUZ) was a project partner of the Institute of Applied Geology (IAG) at the University of Natural Ressources and Applied Life Sciences Vienna (BOKU), the Humanitarian Assistance USA in the Republic of Tajikistan (FOCUS), the Tajik Ministry of Emergency Situations, German Agro Action, and local government agencies. The project was supported by the Swiss Agency for Development (SDC), the UK Department for International Development, and the Aga Khan Development Network.
GIUZ was involved in scenario building of glacial lake outburst floods at six previously identified potentially hazardous study sites that have been simulated with two numerical models. Scenarios with different volumes, outburst mechanisms, debris entrainment characteristics and friction parameters were calculated. The results help local authorities to assess the risk from GLOFs to settlements on debris flow fans and in the major valleys, and to decide on possible mitigation strategies. Within the project, Tajik geologists and hydrologists visited Vienna and Switzerland in spring 2010 and had excursions to various field sites of landslides and debris flows in the Alps. The final report and hazard indication maps serving the Tajik authorities as a basis for decision making were completed in May 2010.

Involved staff from GIUZ:
Demian Schneider, Raphael Worni, Norina Andres, Christian Huggel

Used numerical models:
- RAMMS, by the WSL Institute for Snow and Avalanche Research SLF, Davos-Dorf, Switzerland (http://ramms.slf.ch)
- Flo2D, by Jim O'Brien (www.flo-2d.com)

Reference:
Schneider, J. F., and Mergili, M., et al. (2010): Remote Geohazards in High Mountain Areas of Tajikistan. Assessment of hazards connected to lake outburst floods and large landslide dams in selected areas of the Pamir and Alai mountains. Report of the TajHaz-Project by the BOKU University Vienna and FOCUS Humanitarian Assistance. 342pp (incl. 5 hazard indication maps).