Near the city of Annecy, a moderate but shallow (2-3 km depth) earthquake occurred the 15th of July 1996 on the Vuache fault. It was the strongest event to shake southeastern France in the last 34 years and was responsible of moderate to serious damage in the Annecy area (Thouvenot et al, 1998). The finite ground displacements caused by the quake within few seconds are centimeter and distributed over ten's of kilometers. Levelling data from IGN (French Geographical National Institut) indicate there a 1cm vertical motion in the epicentre area.

For such displacements, only InSAR imagery technique can be used. However, as shown by preliminary study from IPGP, the technique is limited by the small amount of displacement and by land-cover dominated by agricultural activities. Fortunately, a large data set of ERS archive images (~100 images) is available. The challenge is here to recover the reliable phase information, and to transform it into a time series before and after the earthquake with signal/noise ratio enhancement. For that purpose, developments done in WP1, WP3 and WP4 will be fundamental. Then, we hope to constrain the rupture characteristics, the fault segments involved in the earthquake taking advantage of the WP6 improvements. We think that the methodological developments made in the case of Annecy will be applicable to better understand other recent moderate earthquakes in Europe (for example, Grevena, 1995, Umbria, 1997, Athens, 1999).

In outlook, the study by InSAR of shallow moderate seismicity in Europe is expected to take strong advantage of the methodological development proposed. Indeed, moving from centimeter to millimeter accuracy will allow to examine several shallow earthquakes with magnitude ~5.5, which is of major interest in Europe where such moderate seismicity dominates and can be particularly destructive.