The scaling of landslide-dammed lakes

Abstract

The size-frequency distributions of earth surface processes and landforms are often characterized by power-law scaling, indicating invariance over certain scale ranges. Determining such characteristic scaling improved the understanding and prediction of landslide occurrence. However, the scaling of lakes dammed by landslide deposits in rivers received much less attention, despite the effects on the river bed and the natural hazard potential resulting from dam breach. To escape data scarcity, we modeled eight million landslides and more than 50 thousand dammed lakes in eight mountain ranges around the world. We used an approach combining the determination of landslide release zones and volumes based on slope geometry and probability, the simulation of landslide runouts and the filling of depressions in the resulting land surface. The distributions of modeled landslides are in line with field observations and suggest climate as an important control on landsliding via the influence of fluvial and glacial imprint on relief and slope geometry. The size-frequency distributions of landslide-dammed lakes also follow a power-law scaling, but differ from the scaling of landslides. A clear dependence of lake distributions on climate cannot be determined. We attribute this to the role of cross-sectional and longitudinal valley shape facilitating the formation of large lakes also in fluvial mountains with moderate relief.