Switzerland is a nation lying across a number of significant fault lines making it highly exposed to the risk of earthquakes.
The mountainous canton of Valais is the region at highest risk, followed by Basel, Graubünden, the St. Gallen Rhine Valley, and central Switzerland. The largest earthquake in Switzerland’s recorded history occurred in Basel in 1356 and measured 6.6. The image below maps earthquake risk levels across Switzerland.
This week, Switzerland’s seismological service based at ETHZ in Zurich published a report on earthquakes in Switzerland in 2021, reported RTS. Over the year, there were 1,100 earthquakes in Switzerland and nearby regions, a number lower than recent in recent years. However, the magnitude of the quakes was larger. In 2021, there were more earthquakes between 2.5 and 4.1 than the long term average, with three shakes over 4 when there is typically only one. Since 1975, one earthquake above 4 has been recorded annually.
The three 4+ earthquakes in 2021 occurred near the Furka pass (1 July), Arolla (5 October) and Ajoie in the Jura (25 December).