Velocity field of the La Clapiere landslide measured by the correlation of aerial and QuickBird satellite images

Two displacement maps of the La Clapiere'' landslide ( France) have been derived over two periods of 4 years (1995-1999 and 1999-2003) by correlation of aerial photographs and a QuickBird satellite image. The movement of the landslide ranges from 2.5 m to 20 m per year. Those values have been validated over 13 points monitored by conventional tacheometric measurements. Three areas with significant differences in velocity field have been mapped. Limits of those areas are in good agreement with in situ observations. Velocity maps show the low long term temporal variability of the landslide movement and its spatial variability. The optical correlation method using images derived from various sensors ( airborne and spatial) is a promising technique for improving the spatial resolution of velocity field observation of landslides over several years.