Rock fall analysis in an Alpine area by using a reliable integrated monitoring system: results from the Ingelsberg slope (Salzburg Land, Austria)

The present work illustrates the monitoring system of the Ingelsberg slope (Bad Hofgastein, Austria), which hosts one of the most dangerous landslides in the Salzburg Land. It is a rock fall, which can be considered as representative of landslides commonly occurring in the Alpine area. During the monitoring campaign (March 2013–July 2014), a rock fall occurred at the end of April, 2013 that involved 20–40 m3 of rocks. The comparison of surface measurements (by Ground-Based Interferometric Synthetic Aperture Radar—GB-InSAR) with measurements in depth (by extensometers) allowed the understanding of the failure process of the rock mass. Data are discussed taking into account meteorological conditions antecedent to the landslide triggering, indicating that factors such as rapid snow melting (added to first spring rainfall events) and rock thermal dilatation are very important in slopes located far below the permafrost line.