Geometry-Based Preliminary Quantification of Landslide-Induced Impulse Wave Attenuation in Mountain Lakes

Abstract

In this work, a simple methodology for preliminarily assessing the magnitude of potential landslide-induced impulse waves’ attenuation in mountain lakes is presented. A set of metrics is used to define the geometries of theoretical mountain lakes of different sizes and shapes and to simulate impulse waves in them using the hydrodynamic software Flow-3D. The modeling results provide the ‘wave decay potential’, a ratio between the maximum wave amplitude and the flow depth at the shoreline. Wave decay potential is highly correlated with what is defined as the ‘shape product’, a metric that represents lake geometry. The relation between these two parameters can be used to evaluate wave dissipation in a natural lake given its geometric properties, and thus estimate expected flow depth at the shoreline. This novel approach is tested by applying it to a real-world event, the 2007 landslide-generated wave in Chehalis Lake (Canada), where the results match well with those obtained using the empirical equation provided by ETH Zurich (2019 Edition). This work represents the initial stage in the development of this method, and it encourages additional research and modeling in which the influence of the impacting characteristics on the resulting waves and flow depths is investigated.

A Lagrangian-Eulerian procedure for the coupled solution of the Navier-Stokes and shallow water equations for landslide-generated waves

“…In order to assess the quality of the obtained solution, in Fig. 14 we compare the envelope of the maximum wave height measured along sections S1 and S2 with the reference solution given in [70].…”

“…In [70], different metrics of real alpine lakes were used to define the configuration of theoretical mountain basins of different sizes and shapes. These geometries were used in [70] to study LGW scenarios with a finite volume solver and to obtain correlations between the lake configuration and the landslide-generated waves. Here, we analyze one of the lakes considered in [70] to test the proposed coupled strategy in a 3D complex setup.…”

“…These geometries were used in [70] to study LGW scenarios with a finite volume solver and to obtain correlations between the lake configuration and the landslide-generated waves. Here, we analyze one of the lakes considered in [70] to test the proposed coupled strategy in a 3D complex setup. Fig.…”

“…The case study is a circular lake with a diameter of 1500 m. The landslide has a prismatic shape of 20 m thick, 208 m long and 120 m wide. Following [70], a bulk material density of 1620 kg/m 3 is used for the landslide material and an initial velocity of 20 m/s has been prescribed to the sliding body. Preliminary NFS analyses of the LGW scenario showed that the landslide material reaches a deposition distance of around 350m.…”

The 28 November 2020 Landslide, Tsunami, and Outburst Flood – A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada

“…The Elliot Creek event is an example of a, sometimes underappreciated, hazard chain in high mountains experiencing rapid deglaciation. This event finds itself among other disastrous high mountain landslides that generate tsunami (Higman et al., 2018; Roberts et al., 2014) and floods and fast‐moving mass flows (Carey et al., 2012; Glancy & Bell, 2000; Franco et al., 2021; Hermanns et al., 2004; Hermanns, Dahle, et al., 2013; Hermanns, L’Heureux, et al., 2013; Hubbard et al., 2005; Oppikofer et al., 2012; Shugar, Jacquemart, et al., 2021; Vilca et al., 2021). Rapid glacier retreat may increase the hazard of these events as the number and size of lakes increase below potentially unstable slopes in alpine valleys undergoing ice retreat.…”