The dynamics of impact-induced erosive mass flow mobility

Erosion can tremendously amplify the volume and destructive potential of mass flows with spectacularly increased mobility. However, the mechanism and consequences of erosion and entrainment of such flows are still not well understood as these processes are inherently complex due to the composition of the flow as well as the erodible bed material and their physical properties. Erosion rate, erosion velocity, and momentum production are the key factors essentially controlling all the processes associated with erosive mass transport. Here, we present experimental results on the dynamics of impact-induced mobility of erosive mass flows. Experiments are conducted at the Laboratory Nepnova – Innovation Flows in Kathmandu using some native Nepalese food grains as well as geological granular materials. As we focus on erosion in the inclined channel, transition and the run-out zone, we determine how the flow and the bed conditions control the erosion rate, erosion velocity, and the momentum production. This includes the change in volume, composition, and physical properties of the released mass and the erodible bed and its slope. We establish some quantitative functional relationships among the erosion rate, the erosion velocity, and the mobility of the mass transport aiming at providing a foundation for developing predictive models and innovative strategies for erosion control and mitigation from landslide hazard.