| Project Detail |
Mountain permafrost is undergoing substantial modifications due to climate change. In the Alps, a drastic increase in rock glacier creep rates has occurred at the regional scale since the 1990s, concurrent with rising temperatures and increasing ice-water ratios within the permafrost. These observations raise questions on the fundamental mechanisms controlling rock glacier dynamics and their coupling to climate. To answer these questions various research efforts have been undertaken. Statistical analyses of rock glacier velocity time series highlighted strong correlations between creep rates and temperature at multiple temporal scales. Field investigations and modelling studies have also pointed out the critical role of water in determining the short-term velocity variations of rock glaciers. However, our understanding of rock glacier dynamics and their complex interaction with hydrothermal processes remains limited. Furthermore, a detailed and coherent assessment of the evolution of rock glacier dynamics at the regional scale is still lacking due to its multi-disciplinary nature and the former scarcity and limitations of the available data. Therefore, the current state of rock glaciers in Switzerland is largely unknown. In order to address these knowledge gaps, we propose a project aiming to investigate the evolution of rock glacier dynamics at multiple spatio-temporal scales in the Swiss Alps. The project consists of five work packages based on the review and the analysis of readily existing datasets complemented with original observations produced ad-hoc. The main objectives are the following: i) Assess the current state of rock glaciers in Switzerland, by compiling an exhaustive inventory and extracting region-wide kinematic data and time series using remote sensing techniques (optical and InSAR). The statistical analysis of this dataset will allow identifying and weighting the drivers controlling rock glacier velocities at the regional scale. ii) Reconstruct the multi-decennial evolution of numerous rock glacier kinematics in Switzerland. The combined use of historical aerial images and modern remote sensing data will extend multiple time series half a century in the past and increase their temporal resolution and accuracy for recent years. The relation between climate forcing and rock glacier velocities will be investigated on this refined basis. iii) Identify the main physical processes controlling the evolution of rock glacier dynamics. Comprehensive geophysical, geotechnical, hydrological and thermal datasets will be collected at three sites using innovative field investigation techniques, to quantitatively assess the role of water (i.e. water content, infiltration, lateral flow, hydrostatic and pore water pressure) in rock glacier motion mechanisms. iv) Investigate rock glacier dynamics and the specific process of destabilization with numerical models. Existing models will be further developed and adapted to quantitatively investigate the recent rock glacier acceleration and the onset of a destabilization phase from a mechanical perspective. The project is highly collaborative. Its successful achievement will constitute an important step forward in rock glacier research in the Alps and beyond, with wide implications for fundamental research and operational monitoring. It will provide the first comprehensive assessment of rock glacier distribution and kinematics at the regional scale worldwide, setting the Swiss Alps as a benchmark in the study of rock glaciers. It will also provide the first regional investigation of multi-temporal velocity variations, constituting the necessary basis for understanding the complex processes governing rock glacier dynamics and their relation with climate change. |
