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Earthquake Country Switzerland

Using its digital monitoring network, on average the Swiss Seismological Service (SED) registers two earthquakes a day in Switzerland and neighbouring countries, making a total of between 500 and 800 quakes a year. Usually, around 10 to 15 of these events are strong enough (i.e. have a magnitude of 2.5 or above) to be felt by the local population.

Generally speaking, earthquakes occurring in Switzerland results from collisions between the European and the African lithospheric plates.

Compared to the rest of Europe, Switzerland as a whole is prone to a moderate seismic hazard. But earthquake activity is not distributed evenly throughout the country: Valais is the region at the highest hazard, followed by Basel, Grisons, the St. Gallen Rhine Valley, Central Switzerland and then the rest of Switzerland. All parts of Switzerland are exposed to some degree of seismic hazard.

The strongest historically documented earthquake in Switzerland, with a magnitude of approximately 6.6, occurred in Basel in 1356. A destructive earthquake with a magnitude of 6 or higher can be expected to occur every 50 to 150 years. The last time such an event took place was in 1946, near Sierre in the canton of Valais. Such an earthquake could occur anywhere at any time in Switzerland. The last earthquake to have caused damage occurred in 1991 in the area of Vaz in the canton of Grisons.

Map of the instrumental recorded earthquakes between 1975 and 2015 with a minimum magnitude of 2.

Frequency

On average, the Swiss Seismological Service (SED) registers two earthquakes per day in Switzerland and its neighbouring countries, making a total of between 500 and 800 earthquakes a year. Approximately 10 to 15 of these events are strong enough to be felt by the population (i.e. have a magnitude of approximately 2.5 or above).

Earthquakes with a magnitude of at least 5 occur every 8 to 15 years. Larger earthquakes, with a magnitude of 6 or more, occur only every 50 to 150 years. Though rare, they can occur anywhere and at any time in Switzerland. The strongest historically documented earthquake in Switzerland, with a magnitude of approximately 6.6, occurred in Basel in 1356. Such events should be expected to happen roughly once every 1,500 years.

At present, earthquakes cannot be predicted, though it is possible to calculate the probability with which a certain ground acceleration will be exceeded within a given period at any location in Switzerland. Consequently, the country can be divided into lower- and higher-hazard regions. Valais is the region subject to the highest hazard, followed by Basel, then Grisons, the St. Gallen Rhine Valley and Central Switzerland. All regions of Switzerland are exposed to some degree of seismic hazard.