Rock Slope Instability in Recently Deglaciating Cirque Headwalls
Funding Agency: Austrian Academy of Sciences (ÖAW, 2020-2023)
Principle Investigators: Andreas Ewald (PhD Student)
Jan-Christoph Otto, Andreas Lang (University of Salzburg)
Ingo Hartmeyer, Markus Keuschnig (Georesearch Forschungsgesellschaft mbH)
Jeffrey R. Moore (University of Utah)
Alpine glaciers are retreating rapidly and may have disappeared completely by the end of this century. Within glacial cirques, ice down wasting exposes rock surfaces in the steep cirque headwalls resulting in frequent rock slope instability. In recent decades, magnitude and frequency of rockfall and rock slide events in high mountain areas have significantly increased worldwide, and due to the ongoing degradation of the cryosphere will continue to pose an increasing threat to people and infrastructure in alpine regions. In this project, we aim to further our understanding of rock slope instability in deglaciating cirque headwalls to provide a solid scientific base for designing climate change adaptation strategies in high mountain regions.
We focus on the following questions:
- Where are potentially unstable cirque headwalls?
- Which processes destabilise deglaciating cirque headwalls and where are these most efficient?
- Where do rock slope failures initiate and occur?
To address these questions, we will (i) assess the sensitivity of cirque headwalls on a regional scale, (ii) decipher and quantify destabilising processes and (iii) monitor spatio-temporal rockfall activity in different cirque settings.
Three work packages are identified, focusing on 1. preconditioning factors, 2. destabilising processes and 3. rock slope failure:
1. Geoinformation system analyses on a broad spatial scale will be used to identify glacier headwalls sensitive to rock slope instability following glacier retreat by combining high alpine topography, geotechnical parameters and cryospheric conditions including glacier extent and permafrost distribution.
2. Based on the existing research infrastructure at the Open Air Lab Kitzsteinhorn, a novel measurement setup to determine high-resolution fracture displacement will be established in order to detect rock mechanical response to environmental forcing on glaciated, deglaciated and recently deglaciating headwall sections. Destabilising processes will be quantified using a state of the art modelling approach.
3. Spatio-temporal rockfall activity in five different cirque settings will be monitored by repeated laser scanning campaigns to enable bridging the scales between (1.) and (2.) Integrating the three approaches will provide unique data sets, significantly improved understanding of cirque headwall instability and also allow upscaling local information to regional scale.