On 23 June 2020, Switzerland’s seismology service reported an earthquake measuring 3.8 at 8.25 am in Chamonix, France, 4,5 km below the surface.
The shake was felt in parts of the cantons of Vaud and Valais. Comments on Chamonix’s municipal Facebook page reported trembling windows and sounds like an explosion. No damage was reported.
Mountain ranges are built by tectonic plates pushing against each other, making them inherently seismically active. Switzerland hasn’t experienced a large earthquake since 1946 when a 5.9 tremor shook Sierre in Valais.
Valais remains the region in Switzerland at highest risk, followed by Basel, Graubünden, the St. Gallen Rhine Valley, and central Switzerland.
In Switzerland, few Swiss home owners have earthquake insurance, according to Swiss Re and some buildings in risk zones are not designed to withstand a powerful shake.
The largest earthquake in Switzerland’s recorded history occurred in Basel in 1356 and measured 6.6.