Quantitative characterization of subaqueous landslides in Lake Zurich (Switzerland) based on a high-resolution bathymetric dataset

Abstract

New high-resolution surveying techniques allow subaqueous geomorphology to be investigated in great detail. Such analyses are important as the morphologies are often indicative of past processes, including mass movements. For peri-alpine Lake Zurich, many mass-wasting events have occurred in the past millennia. While the ages of these events are known from past studies on the respective deposits in the lake basin, the surface expressions and distribution of the respective features on the slopes have not been extensively described. Here we quantitatively characterize the morphologic features on the entire lake floor. A total of 50 subaqueous landslides are morphologically identified in a high-resolution digital bathymetric model (DBM), mapped and characterized using a geographic information system (GIS). Many slides show relatively small erosion areas (<0.05 km2) and are located in shallow water (<10 m water depth). The roughness of the individual landslide-translation areas is quantified using the standard deviation of a measure called bathymetric position index (BPI) and related to the slides ages. The DBM allows the detection of traces of mass-movements dating back to c. 5000 cal years BP. Our results demonstrate that morphometric analyses on a high-resolution DBM can contribute to a better understanding of sublacustrine mass movements.

The subaqueous landslide cycle in south-central Chilean lakes: The role of tephra, slope gradient and repeated seismic shaking

“…10). By comparison with tsunamigenic sublacustrine landslides in glacigenic peri-alpine lakes (Hilbe et al, 2015;Strupler et al, 2018), we can expect these large events to have caused lake tsunamis with runup heights in the order of ~1-5 m, whereas the smaller landslides likely did not produce significant waves. Our study only addresses landslides on "lateral slopes" (sensu Sammartini et al, 2018) with hemipelagic sedimentation, a setting where landslides are typically of translational nature.…”

“…In terms of triggering mechanisms, human activity (e.g. harbor extensions) plays an important role in generating recent coastal landslides in lakes (e.g., Strupler et al, 2018), fjords (e.g., L´Heureux et al, 2013) and seas (e.g., Dan et al, 2007). For older periods (i.e.…”

Advancing from subaqueous mass movement case studies to providing advice and mitigation

“…Moving to inland waters, the risk of tsunami from lacustrine landslides is sometimes noted, yet remains poorly researched in the literature. Some exceptions include recent assessments for European lakes (Strasser et al 2011;Hilbe & Anselmetti 2015;Strupler et al 2017;Strupler et al 2018). Perhaps this is due to subaqueous geohazard organizations and their research ships having a stronger focus on marine environments and developments.…”

“…In Lake Zurich, Switzerland, several dozen MTDs have been previously published (Strupler et al 2017) based on sub-bottom profiling from portions of the lake. A full multibeam survey and morphometric assessment revealed details of 50 recent subaqueous landslides (Strupler et al 2018).…”

A Simplified Classification of the Relative Tsunami Potential in Swiss Perialpine Lakes Caused by Subaqueous and Subaerial Mass-Movements

“…Next to historically documented lacustrine tsunamis on Swiss lakes, geophysical (i.e., bathymetric and seismic reflection data) and sedimentological data (i.e., sediment cores retrieved at the bottom of several lakes) show evidence of large SAQMM and SAEMM that have occurred since de-glaciation, and many of them are assigned to earthquakes as triggers (e.g., Schnellmann et al, 2002;Monecke et al, 2004;Fanetti et al, 2008;Hilbe et al, 2011;Wirth et al, 2011;Strasser et al, 2013;Corella et al, 2014;Kremer et al, 2015;Reusch, 2015;Fabbri et al, 2017;Kremer et al, 2017;Strupler et al, 2018a).…”