SPCC 5 (ROCKISM): Monitoring and process analysis of permafrost creep and failure in changing temperature regimes

Destabilised rockglacier Grueo 1 in the Turtmann Valley. The picture was taken from helicopter (Photo: I. Gärtner-Roer, 2008).

Project information:

SPCC 5 is part of the ‘Bündel-project: Sensitivity of mountain permafrost to climate change (SPCC)’ and is financed by the German Research Foundation (DFG).

Project goals:

The key question of future permafrost research is to understand the spatio-temporal changes of surface and subsurface processes in response to atmospheric forcings. For the monitoring and process analyses of permafrost creep and failure in changing temperature regimes the following items represent the specific aims to be reached throughout the project:

1.  Permafrost creep rates (kinematics) on rockglaciers and frozen talus slopes will be quantified in different regions of the Alps (Zugspitze/Höllental, Bavarian Alps; Murtèl/Corvatsch, eastern Swiss Alps, Turtmann Valley, southern Swiss Alps). This includes the measurement of annual (by geodetic survey) and perennial or decadal (by digital photogrammetry) kinematics as well as the analysis of spatio-temporal variations. Extraordinary high or low velocities or distinct temporal changes in kinematics within the monitoring period (from ~ 1970 – 2008, depending on the availability of aerial photographs) indicate a response to certain changes within the permafrost system and thus indicate a high sensitivity of the system.
2. In order to analyse the measured kinematics in a rheological context, temperature data (ground surface temperatures (GST) and borehole temperatures from different depths) as well as data on subsurface characteristics will be implemented in addition. These data are partially available for the test sites and will also be recorded during the application period (in cooperation with other “Bündel” projects). The coupled analysis in a numerical model approach will allow for an assessment of how temperature changes will be translated into a rheological response.
3. Landforms showing strong spatio-temporal changes in surface movements, as well as landforms indicating failure will be studied in detail. In the Zugspitze/Höllental-region as well as in the Murtèl/Corvatsch-region such landforms have to be identified first, whereas in the Turtmann Valley at least two rockglaciers indicate strong accelerations in combination with failures. On these landforms, shallow boreholes (6 – 10 m) will be drilled in order to couple subsurface temperature data with recent kinematics. In this context, the investigation of ongoing processes and their sensitivity to temperature variations represents the particular challenge.

The investigations include:

• Quantification of kinematics (horizontal and vertical displacements) as well as spatio-temporal variations in kinematics for several representative rockglaciers and frozen talus slopes in the Alps by means of different methods.

• Detailed investigation of kinematics on landforms showing instabilities and failures and thus indicating high sensitivities.

• Geomorphometrical description of the landforms, including surface structure and patterns and their changes; especially in relation to permafrost degradation and landform failure.

• Coupled analysis of surface kinematics (horizontal and vertical displacements) and ground surface temperatures as well as temperatures in different depths (borehole sites) by numerical modelling.

• Coupled analysis of surface kinematics (horizontal and vertical displacements) and data on subsurface characteristics and their temporal variations (e.g., ice content, unfrozen water content) from geophysical surveys and monitoring (in cooperation with Bündel projects SPCC 2, SPCC3). Of particular interest are hereby e.g. interrelations between water content and kinematics or between kinematics and possible permafrost degradation (or aggradation?) processes (indicated by ice content variations). These interrelationships will also be included in a numerical model.

• Coupled analysis of landform kinematics and rockwall retreat rates in order to describe sediment fluxes (in cooperation with Bündel project SPCC 4).

• Coupled analysis of landform kinematics and regional scale climate modelling (in cooperation with Bündel project SPCC 1). Resulting simulations (amplitude of future atmospheric forcing) from SPCC 1 will be implemented into the above mentioned numerical model.

Overview of the Alpine Arc with the three study sites: 1 = Murtèl/Corvatsch, Grisons, Switzerland; 2 = Turtmann Valley, Valais, Switzerland; 3 = Zugspitze, Bavaria, Germany.

Study sites:

The study sites have been chosen due to the following reasons:

• different geologic and climatic regions in the Alps

• occurrence of different landforms representing permafrost creep (rockglaciers and creeping talus slopes)

• availability of data on permafrost characteristics (occurrence, distribution, thickness, temperatures, etc.) and dynamics from previous and ongoing studies

1.     Murtèl/Corvatsch, Grison, Switzerland

The Murtèl rockglacier is situated below the northern face of Piz Corvatsch (3300 m a.s.l.) in Grison, which lies in the south-eastern part of the Swiss Alps (about 46° 26’N / 9° 49’E). The climate is characterised by air masses from south-west. The annual precipitation averages 800 mm in the valley and 1000-2000 mm in higher altitudes. The lithology mainly consists of granite and granodiorite. Due to the fact of easy accessibility the Murtèl rockglacier is one of the best investigated rockglaciers.

Murtèl-Kar: famous rockglacier Murtèl in the foreground and other creeping permafrost landforms in the background (Photo: I. Gärtner-Roer, 2007)

2.     Turtmann Valley, Valais, Switzerland

The Turtmann Valley is a tributary of the river Rhone and is located in southern Switzerland between the Matter Valley and the Anniviers Valley (about 46° 13´N / 7° 38´E). Due to its inner-alpine location, the area is characterised by an intramontane climate with an annual precipitation of 600-900 mm/a at c. 2000 m a.s.l. The valley’s lithology mainly consists of Paleozoic gneisses and schists. Its geomorphology is dominated by two large glaciers in the valley head and several hanging valleys above the shoulders of the trough. One of the hanging valleys is the Hungerlitälli, which is characterised by numerous rockglaciers in different states of activity.

Hungerlitälli, Turtmann Valley (view to the southeast): a variety of active and inactive rockglaciers (Photo: I. Gärtner-Roer, 2008).

Hungerlitälli, Turtmann Valley (view to the east): a variety of active, inactive and relict rockglaciers. The picture was taken from helicopter (Photo: I. Gärtner-Roer, 2008).

3.     Zugspitze/Höllental, Bavaria, Germany

The Zugspitze (2962 m a.s.l.) is situated in southern Bavaria, Germany, near the border to Austria. The lithology consists mainly of limestone. This site represents the last permafrost occurrence in Germany.

Staff:

• Dr. Isabelle Gärtner-Roer (supervisor)

Department of Geography, University of Bonn, Germany

Cooperations:

• Prof. Dr. Wilfried Haeberli

Department of Geography, University of Zurich, Switzerland

• Prof. Dr. Stefan Hergarten

Institut für Erdwissenschaften, Karl-Franzens-Universität Graz, Austria

• Prof. Dr. Andreas Kääb

Department of Geosciences, University of Oslo, Norway

• Prof. Dr. Sarah Springman

Department of Geotecnics, ETH Zurich, Switzerland

• Patrick Thee

Swiss Federal Institute for Forest, Snow and Lanscape Research (WSL), Birmensdorf, Switzerland

Links to the other Bündel-projects:

SPCC1 "Ground-Atmosphere Modelling of Permafrost Evolution"

SPCC2 "Quantitative assesment of permafrost degradation using coupled geophysical and thermal monitoring systems"

SPCC3 "Spatial assessment of permafrost characteristics and dynamics in alpine periglacial environments"