Mechanisms for the Formation of an Exceptionally Gently Inclined Basal Shear Zone of a Landslide in Glacial Sediments—The Ludoialm Case Study

Abstract

The Ludoialm landslide, which is located in the municipality of Münster in Tyrol, Austria, represents a large-scale translational landslide in glacial soil sediments characterised by an exceptionally low inclined basal shear zone of only 12°. Although a temporal coincidence between meteorological events and slope displacement is obvious, the hydromechanical coupled processes responsible for the initial landslide formation and the ongoing movement characteristics have not yet been identified. This article provides a comprehensive analysis of the predisposition factors and the initial failure mechanism of this landslide from geological and geotechnical perspectives. We use a prefailure geometry of the cross section to simulate the initial slope failure process by a limit equilibrium analysis (LEA), a strength-reduction finite element method (SRFEM), and a finite element limit analysis (FELA). The shape and location of the computationally obtained basal sliding zone compare well with the geologically assumed one. Based on the computational study, it turns out that a high groundwater table probably caused by snow melting in combination with different permeabilities for the different layers is needed for the formation of the exceptionally low inclined basal shear zone. This paper presents the failure mechanism of the Ludoialm landslide and discusses the role of the shear band propagation in the process of slope destabilization.

patrimonio de origen glaciar de la Serra da Capelada (Geoparque mundial de la Unesco Cabo Ortegal, Galicia, Península Ibérica)

“…Se trata de un movimiento post-deposicional, algo que no es excepcional en ambientes que están glaciados en la actualidad o lo han estado en el pasado. Son numerosas las publicaciones sobre el tema (Beló et al, 2006;Shulmeister et al, 2009;Shan et al, 2013;Barboux et al, 2014;Frasca et al, 2020;Ben-Yehoshua et al, 2022;Dai et al, 2023).…”

An Index for Snowmelt-Induced Landslide Prediction for Zavoj Lake, Serbia

“…Applying the model to the Tartano basin in the Alps, the authors found that 26% of slopes exhibited unstable conditions; previous models that used only rainfall-based predictions suggested that only 19% of the slopes were unstable. Snowmelt water was also proposed as a trigger for the Ludoialm landslide in Tyrol, Austria as the groundwater levels increased [30].…”