Seismic Activity in Switzerland

Switzerland – a beautiful country located in the heart of Europe is bordered by Italy, France, Germany, Austria, and Liechtenstein. It is geographically divided among the Alps that occupy the greater part of the territory, the Swiss Plateau, and the Jura mountains.

Geologically, Switzerland is situated on the edge of the Eurasian tectonic plate that subducts under the African plate, which also follows the line of the Alps. Its capital Basel, on the other hand, lies in the so-called Rhine rift valley, which represents a fault in the Earth's crust that opened when the Eurasian continent "[...] fractured along a line running from the North Sea to Switzerland¹."

^{Picture 1: Switzerland is geographically divided among the Alps, the Swiss Plateau, and the Jura mountains.}

How Common are Earthquakes in Switzerland?

Due to its location and the two plates colliding, earthquakes remain a serious hazard for Switzerland. According to the Federal Institute of Technology in Zürich, there are more than 500 earthquakes recorded in Switzerland every year, mostly moderate in magnitude. "But a strong or even catastrophic earthquake could also occur anytime, anywhere in Switzerland²," says the Swiss Seismological Service (SED) at ETHZ.

Moreover, some experts fear that an earthquake could also lead to the occurrence of tidal waves in the country's lakes and reservoirs triggered by landslides.

The Strongest Earthquakes in Switzerland

Although it might not be very evident, earthquakes in Switzerland are quite frequent but rarely severe. The majority of strong earthquakes with a magnitude between 5.0 and 6.5 occurred in the 17^th, 18^th, and 19^th centuries. One of the most recent strong earthquakes had a magnitude of 5.8 and occurred in 1946 in Sierre, while the strongest earthquake ever documented in Switzerland occurred in Basel in 1356 and had an estimated magnitude of 6.6.

The most recent moderate seismic event, however, happened a couple of years ago. That was a magnitude 4.2 earthquake on the Richter scale that occurred near the city of Zug in central Switzerland. Although it was fairly moderate in magnitude, this event was felt by tens of thousands of people across central and eastern Switzerland.

The Most Earthquake-Prone Regions in Switzerland

The earthquake risk in Switzerland today is classified as moderate to average but "given the density of the population and property in risk areas such as the Basel region, a severe earthquake is the kind of natural disaster with the greatest potential for destruction in Switzerland³."

Due to their location and geological structure, the most earthquake-prone area in Switzerland is canton Valais, followed by Basel, Graubünden, the St Gallen Rhine Valley, and central Switzerland.

Picture 2: Matterhorn is the highest peak in Switzerland located on the border between Switzerland and Italy.

Sources:
1) Swissinfo.de. Quakes Remain 'Serious Hazard' for Switzerland. Accessed on 10-Oct-2022. Available at: https://www.swissinfo.ch/eng/seismic-situation_quakes-remain--serious-hazard--for-switzerland/41636394 
2) Swissinfo.de. Quakes Remain 'Serious Hazard' for Switzerland. Accessed on 10-Oct-2022. Available at: https://www.swissinfo.ch/eng/seismic-situation_quakes-remain--serious-hazard--for-switzerland/41636394 
3) Swissinfo.de. Quakes Remain 'Serious Hazard' for Switzerland. Accessed on 10-Oct-2022. Available at: https://www.swissinfo.ch/eng/seismic-situation_quakes-remain--serious-hazard--for-switzerland/41636394