Rock Slopes Failure Susceptibility Analysis: From Remote Sensing Measurements to Geographic Information System Raster Modules

Problem statement: Two important step can be recognised in the rockfall analysis: the potential failure detection and the run out simulation. Analyzing the stability of rock slopes, most important kinematisms are planar or wedge slidings and topplings. The aim of this study was to coupling a deterministic approach for landslide initiation (potential rockfall source areas) with a runout analysis by developing new GRASS GIS raster modules. A case study in the Ossola Valley, at the border between Italy and Swiss, was discussed. Approach: New GIS raster modules for rockfall analysis were developed. Slope stability modules were based on rock mass classification indexes and on limit equilibrium model, while the prediction of rockfall travel distance was based on the shadow angle approach. Results: The study highlighted the importance of GIS tools for analysis of landslide susceptibility. The spatial forecasts provided by the new GIS modules were validated and supplemented by traditional analysis. Conclusion: This study proved that there is a good correspondence between the prediction of high attitude to instability calculated by the modules and the location of past events. The new modules have provided an opportunity to assess, in an objective and repeatable way, the susceptibility to failure and also quantitative information about area of invasion for rock falling.