Brief communication: Depth-averaging of 3D depth-resolved MPM simulation results of geophysical flows for GIS visualization

Abstract. Significant advances in full-3D modeling of geophysical flows have provided deeper insights into complex processes and predictive potential. However, practical application in the natural hazard community remains limited due to inadequate GIS integration of simulation results. This study addresses the oxymoronic transformation of 3D depth-resolved MPM simulation outputs into simplified depth-averaged results, such as flow depth and thickness, and slope-parallel and slope-normal velocities. Specifically, we present an algorithm that rasterizes scattered MPM outputs into a 2D format, enhancing their utility for hazard mapping and mitigation. We demonstrate our approach by applying it to an ice avalanche event, which is simulated using MPM and visualized in GIS. Notably, the 3D MPM shows slope-normal flow velocity components over terrain jumps, and our algorithm enables the identification of flow detachment from the terrain, which depth-averaged models typically neglect.