Landslide susceptibility and controlling factors: An assessment in the Fagnano Lake Basin

Abstract

Slope stability is controlled by multiple factors, including bedrock properties, topography, lithology, structural features, climate, and seismicity. However, their specific role in landslide dynamics remains poorly understood in many under-studied regions. This study presents the first comprehensive landslide inventory for the Fagnano Lake Basin, aiming to analyze the influence of these factors on mass movement processes. Using a GIS-based approach, we integrate seismicity, proximity to tectonic structures, lithology, and topography to assess their contribution to slope failures. Our susceptibility map correlates well with the spatial distribution of the 473 identified landslides, which include slides, flows, slope deformations, and falls, with flows being the most common. While shallow landslides occur frequently, deep-seated landslides cover larger areas and involve greater material displacement. Large-scale flows and slides dominate, whereas slope deformations have a more limited geomorphic impact. Seismic activity linked to the Magallanes-Fagnano Fault System (MFFS) plays a significant role in triggering shallow landslides, particularly in the Hope Mounts and western Fagnano Lake Basin. Our findings suggest that landslide occurrence results from complex interactions between tectonic, topographic, and seismic factors, particularly in the Sierras de Beauvoir and Hope Mounts. However, further investigation is needed to assess seismic influences on other MFFS structures with limited recent documentation. This research provides essential insights into landslide susceptibility in a region lacking prior comprehensive studies, emphasizing its importance for hazard assessment and mitigation efforts.