Quantifying Landslide Activity and Contribution to Sediment Fluxes with Cosmogenic Radionuclides (CRN) and Grain Size Distributions

Landslides are the primary erosional mechanism in mountainous areas, and one of the most hazardous geological phenomena. However, it remains extremely difficult to constrain long-term or past rates of landslide activity, because the physical record of landslides is often removed by erosion in less than 100 years. The aim of this project is to develop and apply a new methodology for quantifying long-term (~100-1000 years) landslide rates and contributions to sediment fluxes, by using CRN multi-nuclide analyses (¹⁰Be and ¹⁴C) on different grain sizes, in combination with detailed field grain-size surveys, and integrating these data into a new numerical model. This project addresses two key research questions:

1. What are the distinct signals of landslide activity preserved in the grain-size distributions and CRN concentrations of landslide deposits and fluvial sediments?
2. How can these grain-size distributions and CRN signals be used to estimate catchment-averaged, long-term landslide rates and landslide-derived sediment fluxes?

Field areas include the Fiordland and Southern Alps of New Zealand, and the Southern Apennines and Calabrian Arc in Italy.

Associates

• Stefanie Tofelde, Mitch D’Arcy & Aaron Bufe
• Hella Wittmann-Oelze & Dirk Scherler (Earth Surface Geochemistry)
• Jeff Prancevic & Maarten Lupker (ETH Zurich)