A Framework for Simulating the Evolution of Underwater Landslides and Its Application to Slope Failures in Swiss Lakes

Destructive underwater mass movements can impose a threat to off-shore infrastructure and near-shore communities. Yet predicting their formation and failure mechanisms remains a major challenge, in part due of the large variety of factors affecting their stability over time. Long-term processes such as sedimentation as well as short-term events such as earthquakes can impact the stability of the slope highlighting the need for an integrated analysis procedure to quantify their impact. In this article, such a framework is presented to simulate the evolution of subaqueous landslides, ranging from sediment deposition to seismic triggering to the postfailure evolution of the collapsing soil mass. Each stage is simulated in an individual step, based on different finite element-based methodologies, to best model the governing processes. The steps are linked in a consistent manner to facilitate the simulation of the landslide evolution as a continuous process. The presented framework is applied to analyze three historical landslide events in Swiss lakes. The model predictions compare well with the in situ landslide deposits. The simulation results provide insight into slope failure mechanisms and effects of seismic ground motion characteristics on the stability of the analyzed slope failures.