How much of a risk are tsunamis in Switzerland?

Tranquil for now: Lake Lucerne, where researchers are placing sensors as part of their work on tsunamis © KEYSTONE / URS FLUEELER

A Swiss research project has been looking at the risk of tsunamis occurring in lakes in Switzerland – it’s a phenomenon that has already occurred on lakes Lucerne and Geneva.

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On September 16, 1601 a tsunami flooded the banks of Lake Lucerne in central Switzerland and the city of Lucerne. The tidal wave was the result of a 5.9 magnitude earthquake, which triggered several underwater landslides as well as a rockslide on the Bürgenstock mountain. It is estimated that the wave reached four metres in height. At least eight people died.

Researchers, which include the Federal Institute of Technology Zurich (ETH Zurich) and the University of Bern, have been running a major research projectExternal link to learn about the hazards of lake tsunamis, how often they occur, what triggers them and what effects they have.

“Tsunamis in lakes might be rare events, but they do have this potential to cause great damage,” said the ETH Zurich’s Donat FähExternal link, who co-leads the project, in a statementExternal link released to mark one year of the project.

“The history of tsunamis in Swiss lakes proves this. Just like any other natural hazard, they therefore need to be studied and quantified to allow us to define preparatory measures,” said the head if the Earthquake Hazard & Risk Assessment section of the Swiss Seismological Service.

The project focuses on taking seismic measurements in Lake Lucerne, by putting special underwater seismometers in various locations to obtain seismic and geotechnical measurements on the lake floor.

Researchers are also studying landslides in river deltas. They are examining cores drilled on the shoreline and in the lake bed to find deposits by tsunamis and are also using computer models to simulate a tidal wave on the lake.

Ocean application

“The project is a classic study of natural hazards in Switzerland,” said Flavio AnselmettiExternal link, of the University of Bern and the other project leader, in the statement. Lakes offer the perfect model for understanding oceans and the knowledge the team gains from this project is likely to be applied to oceans as well, added the geology professor.

There are three more projects planned as part of the tsunami research, which has received CHF2 million ($2.1 million) in funding from the Swiss National Science Foundation, ETH Zurich and the Federal Office for the Environment.

Lake Lucerne is not the only lake known to have been affected by a tsunami. A studyExternal link by the University of Geneva published in Nature Geoscience in 2012 pointed to a catastrophic tidal wave on Lake Geneva in 563, caused by a mountain landslide in Valais.