Modelling Rockfall Source areas and hazard zoning along the Rhine-, Ahr- and Moselle-valleys in the Rhenish Massif, Rhineland-Palatinate, Germany

Rockfall events, due to toppling or sliding rock slope failure are a common phenomenon within the Rhine-, Ahr- and Moselle-valley of the Rhenish Massif. Due to the dense traffic infrastructure, significant cases of damage with far-reaching economic and infrastructural consequences regularly occur in these areas. Therefore, there is a specific need for precautionary risk analysis in order to prevent further damage and to implement preventive measures. The research approach presented here aims to identify rockfall endangered zones for adjacent infrastructure in the valleys. It is assumed, that the main reason for these frequent occurrences are the high number of exposed rock faces and a complex fabric of intersecting foliation-, fracture- and cleavage- networks and faults. By using an index, calculated from the slope and real-surface area of high-definition LIDAR based DEM it is possible to extract areas with exposed rock faces as possible sources for rockfall modelling. To single out which parts of the outcrop are more likely to fail, we compute the aspect of natural occurring outcrops, characteristic of fabric orientations along which failure preferably takes place and pinpoint locations with highly varying directions. These intersection points, representing weakened areas within the outcrops serve as sources for our rock fall models using the Gravitational-Process-Path-Model by Wichmann (2017). Through the precise identification of the rockfall source areas and further input data like vegetation and relief energy numerous cases in the valley were modelled. By intersecting with real infrastructure data, it is possible to carry out risk assessments of specific sections of roads and railway lines. Validation using the mass movement database of the Rhineland-Palatinate Geological Survey and numerous ground checks show, that concrete rockfall events were plausibly simulated.