A workflow for the rapid assessment of the landslide-tsunami hazard in peri-alpine lakes

Abstract

Although lake tsunamis constitute a rare peril, they have repeatedly occurred in peri-alpine lakes in the past. There are several documented historical examples of landslide-triggered tsunamis in Swiss lakes. However, fundamental information and workflows to rapidly quantify the lacustrine tsunami hazard for multiple lakes are missing so far. The fact that the shorelines of major peri-alpine lakes are densely populated underlines the need for a hazard assessment. Detailed assessments require high-resolution geophysical, geotechnical and sedimentological data, and considerable computation time. Due to the involved data acquisition and calculation efforts, such assessments are mainly conducted as detailed case studies for single lakes. We present a workflow for a rapid first-order estimation of the landslide-triggered tsunami hazard along the shores of peri-alpine lakes. A crucial step is the identification of potential tsunami sources. Unstable slopes are mapped automatically, based on parameters that are derived from past studies. Such parameters include the bathymetry and derived parameters, and type, characteristics and thickness of the sediments. Wave amplitudes are estimated with existing predictive equations, based on the constructed maps of potentially unstable slopes. The results may be used for focusing more detailed, lake-specific tsunami-hazard assessments in respective areas.

Shallow‐Water Tsunami Deposits: Evidence From Sediment Cores and Numerical Wave Propagation of the 1601 CE Lake Lucerne Event

“…However, this phenomenon was not included in this study. Beyond that, this approach could be used for a rapid tsunami hazard assessment for subaqueous mass movement‐generated tsunamis in lakes (Strupler, Anselmetti, et al., 2020).…”

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

“…Further development of the approach should consider different impacting locations along the lakeshore to extend the applicability of the suggested method. Moreover, it would be valuable to consider submerged slide sources, as subaqueous mass movements can also trigger lake impulse waves [47,48].…”

Geotechnical characterization and stability analysis of subaqueous slopes in Lake Lucerne (Switzerland)

“…In contrast, the infinite slope and LEM methods are quite conservative and simplistic but allow a rapid assessment of the slope stability at multiple locations and large areas, thus they are widely used in different case studies (Strasser et al 2011;Duncan et al 2014;Strupler et al 2018a;Carlton et al 2019). The most crucial parameters for the stability analysis are the undrained shear strength and the unit weight of the sediments together with the slope angle (e.g., Sultan et al 2010;Ai et al 2014;Wiemer et al 2015;Strupler et al 2020). To derive these parameters, detailed morphological and geotechnical (in situ and/or laboratory) site investigations are required.…”

“…Within the past investigations in Lake Lucerne, a multitude of geological, geotechnical and geophysical data has been collected, in particular, a high-resolution bathymetry map of the lake floor, a dense grid of reflection seismic profiles, and seismic ambient vibration measurements; also, the chronology of past mass movements has been established (Finckh et al 1984;Schnellmann et al 2002Schnellmann et al , 2004Schnellmann et al , 2006Stegmann et al 2007;Strupler 2012;Hilbe and Anselmetti 2014b;Hammerschmidt 2019;Shynkarenko et al 2021;Lontsi et al 2022). The question of the present-day and past stability of subaqueous slopes in Lake Lucerne was addressed using the LEM in Strasser et al (2007Strasser et al ( , 2011, Hilbe and Anselmetti (2015) and Strupler et al (2020). These studies showed that the failure plane for the lateral non-deltaic slopes is embedded within the glaciolacustrine sediments, thus the failure-prone sediment drape consists of the fine-grained lacustrine and glaciolacustrine sediments and usually has a thickness between 0 and 15 m depending on the slope morphology and history of the past mass movements.…”