Monitoring active rock glaciers in the Western Swiss Alps: Challenges of Differential Sar Interferometry and solutions to estimate annual and seasonal displacement rates

This paper describes a new method to monitor active rock glaciers using DInSAR technique with Terrasar-X data acquired with mode facing slope and 11 days time interval during late summers 2009 to 2011. Where the spatial distribution of the rock glacier surface deformation derived from the DInSAR data using conventional unwrapping processes fails due to the relative small size and the complex movement of some rock glaciers, a specific profile is here defined through the rock glacier and is used to analyze the DInSAR products along it. Firstly, the prerequisites to perform such analysis at local scale are given. Then a quantification and discussion of results are achieved through different examples of active rock glaciers encountered in Western Swiss Alps.