A dynamic earthflow model

Abstract

Earthflows are landslide processes characterized by the viscous movement of predominantly fine-grained and often water-saturated material down a slope or gully. They occur at a broad range of velocities, but generally do not display extremely rapid movement (such as debris flows, snow avalanches, or rock avalanches). Examples include the Gschliefgraben earthflow in the Austrian Alps and the Chirleşti earthflow in the Romanian Carpathians. Although earthflows are common mass movement processes, they have not received the same attention as extremely rapid flows when it comes to the development of dynamic simulation models. Here, we present a novel mechanical model and dynamical solution technique for earthflows. We develop a strategy of balancing the flux, viscous, and other forces. Our model essentially employs the flux-controller, viscosity-controller, and the deformation-controller. Within a single unified frame, we can now simulate a broad range of earthflows for different viscous, plastic, or visco-plastic behaviours and any degree of mechanically controlled deformation over a wide spectrum of time scales. We demonstrate the performance of the new earthflow model and its applicability with the advanced open-source computational mass flow simulation tool r.avaflow. Simulated earthflow deformation and motion are very smooth, typical of a hugely viscous material, as it is anticipated for earthflows as commonly observed for real-world events. As expected, the motion and deformation are exceptionally sensitive to the changes in the viscosity of the earthflow.