r.avaflow v4, a multi-purpose landslide simulation framework

Abstract. We present r.avaflow v4, an enhanced version of the open-source mass flow simulation tool r.avaflow. The updated version includes, among other new functionalities, (i) a layered model, where the individual phases move on top of each other instead of mixing; (ii) a sliding model, supporting the entire range from block sliding to full deformation; (iii) a slow-flow model, allowing for the simulation of landslides beyond extremely rapid processes, using an equilibrium-of-motion model; and (iv) an interface for 3D and virtual reality visualization of the results. We use four case studies to demonstrate the functionalities introduced to r.avaflow v4 and to discuss the related chances and challenges: (i) a generic planar rock slide with interlayer shearing, and (ii)–(iv) semi-generic representations of the prehistoric Köfels rock slide (Austria), the prehistoric East Fogo landslide and tsunami (Cape Verde), and the Dösen rock glacier (Austria). Our results clearly reveal the high potential of the additional functionalities to widen the scope of r.avaflow beyond the simulation of extremely rapid and freely deforming mass flows. Combinations of the layered model, the sliding model, and the slow-flow model unlock potentials yet barely explored in the field of GIS-based landslide simulations. In addition, the layered model facilitates a more realistic simulation of landslide-reservoir interactions. We also highlight the limitations regarding the physical basis and the application of the functionalities presented. Our enhancements are particularly useful for improved process visualization targeting at awareness building and environmental education. They are also suitable to be used for scenario-based predictive simulations in combination with a thorough empirical evaluation campaign.