Seven small earthquakes shake southwest Switzerland

The first tremors were recorded close to the Wildhorn peak, about 8km southeast of the Sanetsch Pass between cantons Bern and Valais. WIkimedia Commons

Switzerland was hit by seven small earthquakes early on Tuesday morning in the high mountain region between cantons Bern and Valais. No damage was reported.

The first 3.3-magnitude quake struck at 1.54am on Tuesday at a depth of 5.3 kilometres, according to the Swiss Seismological Service (SED) at the Federal Institute of Technology, ETH Zurich.

A second 3.3 tremor was recorded at 4.36am at a depth of 4.7 kilometres. The epicentre was towards the Wildhorn peak, about 8km southeast of the Sanetsch Pass.

Two more tremors (2.5 and 2.9 magnitudes) were reported at 6.55am and at 7am, near Arpelistock, another peak located on the border between cantons Valais and Bern. A new tremor occurred at 8.18am in the Wildhorn region, followed by one at 2.7 on the Richter scale at 8.47am near Anzère and a last of similar magnitude near Arpelistock at 9.54am.

SED seismologist Philipp Kästli told the Keystone-ATS news agency that this kind of succession of tremors is not unusual. After the first earthquake, over fifty small aftershocks were recorded between the tremors.

The Valais cantonal police said no damage was reported.

A 3.9-magnitude earthquake shook Albstadt, Germany, about 50 kilometres northeast of Schaffhausen, Switzerland, between Sunday and Monday.

Some 1,200 earthquakes have been recorded in Switzerland since the beginning of 2019, according to the SED website, most below 2.5 magnitude.

Canton Valais remains the area with the highest level of hazard, followed by Basel, Graubünden, the St Gallen Rhine Valley and central Switzerland. 

Historical data indicates that a major earthquake ( +6 magnitude) occurs every 100 years in the Valais region. 

The most devastating earthquake recorded in central Europe occurred in Basel in 1356, with a magnitude of 6.5 to 7.0 on the Richter scale. According to seismologists, an earthquake with a similar intensity can be expected to recur about every 1,000 years.