DETECTION OF THE SAINT-ETIENNE-DE-TINEE LANDSLIDE USING SAR INTERFEROMETRY AND MODELING

SAR interferometry allows the detection of very smalt ground surface m otion (centimetre scale) with high spatial resolution and dense covera ge. It can lead to the construction of a continuous displacement field . Using this technique, the landslide of St-Etienne-de-Tinee in the Fr ench Alps (44.25 degrees N, 6.96 degrees E) is studied. Surface displa cements are determined using an interferogram built with two SAR image s taken 9 days apart in August 1991. Synthetic interferograms, calcula ted for different sliding models, allow us to determine the style of d eformation. A translational sliding model with a gradient of displacem ent from top to bottom, on which three shear zones corresponding to N2 0 degrees sub-vertical faults are superimposed, account for the observ ed fringes.