Movement detection by InSAR in permafrost areas. Application to the Queyras Natural Regional Park, Hautes-Alpes, France. T. Echelard 1 , J.-M. Krysiecki 1 , C. Barboux 2, 3 , M. Gay 2 , P. Schoeneich 1 1 PACTE/Territoires, Joseph Fourier University, Grenoble, France. 2 GIPSA-Lab, Joseph Fourier University, Saint Martin d’Hères, France. 3 Geosciences Department, University of Fribourg, Fribourg, Switzerland. Interferometric Synthetic Aperture Radar (InSAR) is a method of measurement based on the phase differ- ence between two radar images, which represent the same area but at different time intervals. The tech- nique generates interferograms, maps of surface de- formation in two-dimensions allowing for the detec- tion and quantification (in the centimetre range) of variations in distance between the target and the ra- dar between two different data acquisitions. Recent research has shown that the InSAR technique can be used to quantify rockglacier deformation (under the assumption that certain conditions are respected with regard to generating and interpreting the interfero- grams) (Strozzi et al., 2004). The present study aims to detect and describe movements in permafrost. The radar images (dating from 1993 to 1999) were obtained by GIPSA-Lab (Grenoble, France) with the aim of generating inter- ferograms. In contrast to previously used detection methods (Delaloye et al., 2005), which follow an empirical analysis of the interferograms, the present study suggests a method of automatic detection of deformation zones (figure 1) through the use of con- fidence and coherence images (Barboux et Gay, 2009). The final product is a raster image represent- ing the zones of movement. Figure 1 : Movement detection process (C.Barboux, 2009). The research aims to validate the methodology used by analysing the movement polygons obtained. With the interferograms covering a considerable proportion of the Southern French Alps, an first study has been carried out which focused on the Queyras Natural Regional Park. Here, the topo- climatic conditions are conducive to the develop- ment of periglacial formations. Four different time scales are provided: one month, two months, one year and two years, allowing for the identification of four different movement rates (cm/month, cm/2months, cm/year and cm/2years respectively). A periglacial landform inventory was completed to provide a range of potentially creeping formations. For each landform several variables (aspect, mini- mum and maximum altitude, activity, potential re- ceived solar radiation, etc.) were described and col- lected in a data base. The aim was to compare the inventory with the detected movement zones by In- SAR. Measurements of the movement on two rock- glaciers were carried out in the field (DGPS). Using the results of this validation, statistical analyses were carried out to allow greater understanding of the lim- its of the InSAR method. The ultimate objective of the study is to allow for the inventory of creeping landforms over vast areas (100 km width for ERS-1-2 by 100 km length mak- ing 10,000 km 2 ) and to keep a record of their evolu- tion. This work is part of the Alpine Space PermaNET project. References : Barboux, C., Gay, M., Vasile, G. (2009). Permafrost De- tectionin the French Southern Alps, European PermaNET project of Alpine Space program, working paper (unpub- lished). Strozzi, T., Kääb, A. & Frauenfelder, R. (2004). Detecting and quantifying mountain permafrost creep from in situ inventory, space-borne radar interferometry and airborne digital photogrammetry. International Journal of Remote Sensing, 25(15): 2919-2931.