Regional Mountain Conference

The capability of physically-based models to simulate natural hazards under diverse scenarios, including climate-change scenarios, also allows them to function as exploratory tools for investigating the underlying processes of natural hazards and their interactions. Most existing physically-based natural hazard models are restricted to simulating single hazard types (e.g., debris flows, shallow landslides or floods) and are not suited for providing insight into the process interactions within multi-hazards. Additionally, these models generally do not consider the influence of hazards on the landscape and consequently fail to capture how such changes affect the occurrence of future hazards.

Landscape evolution models, which are capable of modelling landscape changes over long time periods, provide a perfect basis to comprehensively analyze multi-hazard processes and the feedback loop between hazards and landscape changes. The landscape evolution model CAESAR-Lisflood is particularly well-suited for this purpose, since it already incorporates sediment transport and river flooding processes. Therefore, this study aims to integrate slope stability and landslide runout components within the CAESAR-Lisflood model and develop a multi-hazard model capable of incorporating landscape changes. Our first steps are to determine the required level of complexity for the additional components, to ensure that we can retain the low input data and calibration requirements of the CAESAR-Lisflood model as well as its computational efficiency. We are also evaluating which existing methods for landslide runout and debris flow modelling could potentially be integrated (e.g., the MassWastingRunout tool from the Landlab toolkit). These methods are tested on a multi-hazard event in 2015 in the Sellrain valley (Austria), where an intense rainfall storm triggered a large debris flow and a large number of shallow landslides.