An assessment of runout models applied to rock fall events in Norway

Abstract

Runout models are an essential tool in evaluating the risk of infrastructure being impacted by mass movements. Rockfalls are a particular type of gravity driven mass movements (landslide). They tend to involve the fall of small groups or volumes of rock blocks rather than rock avalanches that involve large volumes of rock (> 100000m3 ). Rock falls inherently have a high degree of variability du to block size, shape, slope and terrain, and have proven difficult to model accurately. In this study, the usefulness of four different rock fall runout models will be addressed by comparing results from each model to previous rock fall events. These models include two 3D models (RAMMS, RockyFor3D) and two 2D models (Rocfall and CRSP). Given the large effect of small terrain features on a rock trajectory, a high accuracy Digital Elevation Model (DEM) acquired from a Light Detection and Ranging (LIDAR) survey is used along with detailed eld observations to generate terrain models. These terrain models are used as the basis for all the runout models. The implications of the results could possibly affect the software choices of official agents involved in infrastructure maintenance and planning.