Large landslides turn into an avalanche-like mode of flow at high velocities, which allows for a much longer runout than predicted for a sliding solid body. In this study, the Voellmy rheology widely used in models for hazard assessment is reinterpreted and extended. The new approach predicts the increase in runout length with volume observed in nature quite well and may thus be a major step towards a more consistent modeling of rock avalanches and improved hazard assessment.

Rockslides are a major hazard in mountainous regions. In formerly glaciated regions, the disposition mainly arises from oversteepened topography and decreases through time. However, little is known about this decrease and thus about the present-day hazard of huge, potentially catastrophic rockslides. This paper presents a new theoretical framework that explains the decrease in maximum rockslide size through time and predicts the present-day frequency of large rockslides for the European Alps.

This study uses dendritic flow patterns to analyze the recession behavior of aquifer springs. The results show that the long-term recession becomes slower for large catchments. After a short recharge event, however, the short-term behavior differs strongly from the exponential recession that would be expected from a linear reservoir. The exponential component still accounts for more than 80 % of the total discharge, much more than typically assumed for karst aquifers.

The transition from hillslopes to channelized flow is typically attributed to a threshold catchment size in landform evolution models. Here we propose an alternative concept directly based on topography. Using this concept, channels and hillslopes self-organize, whereby the catchment size of the channel heads varies over some range. Our numerical results suggest that this concept works better than the established idea of a strict threshold catchment size.

In this study, we benchmark a topography-based model for glacier erosion (OpenLEM) with a well-established process-based model (iSOSIA). Our experiments show that large-scale erosion patterns and particularly the transformation of valley length geometry from fluvial to glacial conditions are very similar in both models. This finding enables the application of OpenLEM to study the influence of climate and tectonics on glaciated mountains with reasonable computational effort on standard PCs.

Many studies on modeling landform evolution have focused on mountain ranges, while large parts of Earth's surface are quite flat and alluvial plains have been preferred locations for human settlements. Conducting large-scale simulations of fluvial erosion and sediment transport, this study reveals that rivers in a tectonically inactive foreland are much more dynamic than rivers in a mountain range; the local redistribution of deposits in the foreland is the main driver of the dynamics.

The influence of climate on landform evolution has attracted great interest over the past decades. This paper presents a simple model for simulating the influence of topography on precipitation and the decrease in precipitation over large continental areas. The approach can be included in numerical models of large-scale landform evolution and causes only a moderate increase in the numerical complexity. It opens a door to investigating feedbacks between climate and landform evolution.

This paper presents a new approach to modeling glacial erosion on large scales. The formalism is similar to large-scale models of fluvial erosion, so glacial and fluvial processes can be easily combined. The model is simpler and numerically less demanding than established models based on a more detailed description of the ice flux. The numerical implementation almost achieves the efficiency of purely fluvial models, so that simulations over millions of years can be performed on standard PCs.

This study relies on topography to simulate the origin and displacement of potentially river-blocking landslides. It highlights a continuous range of simulated landslide dams that go unnoticed in the field due to their small scale. The computation results show that landslide-dammed lake volume can be estimated from upstream drainage area and landslide volume, thus enabling an efficient hazard assessment of possible landslide-dammed lake volume – and flooding magnitude in case of dam failure.

Many contemporary models of large-scale fluvial erosion focus on the detachment-limited regime where all material entrained by the river is immediately excavated. This limitation facilitates the comparison with real river profiles and strongly reduces the numerical complexity. Here a simple formulation for the opposite case, transport-limited erosion, and a new numerical scheme that achieves almost the same numerical efficiency as detachment-limited models are presented.