Lake Tsunamis

Tsunamis do not only happen in oceans, but they do also occur in lakes. This project aims to understand the trigger mechanisms, preconditions, processes and impacts of lake tsunamis within an interdisciplinary environment (limnogeologists, seismologists, geotechnical specialists, hydraulic engineers and hazard specialists). Two Work Packages of this project (WPresponse and WPhazard/ Tsunami-CH) are conducted at SED.

WPresponse aims to characterize the sediment-mechanical characteristics,to estimate the volumes of the sediments in Lake Lucerne, and to study the stability of the sediments under seismic shaking. For this purpose, ocean bottom seismometers (OBS) are placed in Lake Lucerne at selected locations (see map). These OBS are recording the seismic signal on short (days) and long (months) intervals. Cone Penetration Test (CPT) measurements are used to define the geotechnical characteristics of the sediment. This WP is financed by SNSF and ETH.

WPhazard aims to assess the tsunami hazard in Switzerland. Even though historical reports and studies of lake sediments in Switzerland are documenting numerous tsunamis, the basics and methods for assessing this danger - and the resulting risk on land - are still lacking. Also the typical warning times, the possibilities and limits of alarming are currently only insufficiently known. This work package, financed by the FOEN, is intended to comprehensively characterize for the first time the danger of tsunamis in Swiss lakes such as Lake Lucerne, Lake Brienz, and others and thus contribute to a sustainable and practice-oriented risk management.