2025-01-30
Earthquake activity in 2024
2024 was a record year: there were some 2,300 recorded earthquakes in Switzerland and neighbouring regions, substantially more than the previous annual high of 1,660 earthquakes in 2019. There are many factors behind this record, which are not yet fully understood. As well as active earthquake sequences, a dense measurement network and improved assessment methods, external influences such as glacier melt in high mountain regions and heavy precipitation in the early summer might have played a role. Of the 2,300 earthquakes, 47 had a magnitude of 2.5 or more, and two a magnitude of over 4.0. The strongest earthquake was a magnitude-4.4 event in the Upper Sihl Valley in the canton of Schwyz on 4 June.
Switzerland is an earthquake country. In 2024, the Swiss Seismological Service (SED) at ETH Zurich recorded more earthquakes than ever before in its history of instrumental recording. Among other factors, various earthquake sequences contributed to the unusually large number of earthquakes across the year. In the French–Italian Alps around the Grandes Jorasses (France/Italy) alone, just a few kilometres from the Swiss border, 370 quakes were recorded. The sequence near Réclère in the Jura Mountains and at Lenk in the canton of Bern and the sequences in the Swiss border region near Mulhouse (France), Sierentz (France) and Singen (Germany) continued to be active. The expansion of the seismic network and improved assessment methods also mean that lower-magnitude earthquakes can be recorded ever more reliably.
Earthquakes are caused by a sudden release of stress along faults in the Earth's crust. External influences can also affect the stress regime in the subsoil. Water in particular has the potential to change tectonic processes in various ways. Given the significant rise in earthquakes since the early summer, the SED is investigating whether and to what extent increased glacier melt or heavy precipitation affected the earthquake rate in 2024.
The strongest earthquake in 2024
The biggest quake in 2024 hit the Upper Sihl Valley (canton of Schwyz), in the Ochsenboden region, at 2.34 a.m. on 4 June. This was the strongest earthquake in Switzerland since the magnitude-4.6 Urnerboden earthquake in 2017 and one of the strongest in the last 40 years. The 370 or so reports from the public were limited to a relatively narrow radius of under 30 kilometres. This was due both to the shallow depth of around 1–2 kilometres and to the fact that the quake happened in the early hours of the morning when many people were asleep. A lot of those near the epicentre also typically heard a bang, arising when the ground vibrations were transmitted to the air and converted into audible sound waves. The earthquake caused minor damage in some places (smashed windowpanes, hairline cracks and flaking plaster). It may also have triggered a small landslide near the epicentre, precipitated by the rainfall preceding the quake. Similar shallow events have been recorded previously in this region, with its highly fractured karst rock.
Other felt earthquakes
The second strongest earthquake reached a magnitude of 4.2 and occurred around 15 kilometres north of the Swiss border in the Black Forest near Todtmoos (Germany) on the night of 27 June. This was distinctly felt in northern Aargau, waking up some of the residents. The 2,700 reports were mainly from the cantons of Basel-Landschaft and Schaffhausen as well as from northern Aargau.
All the other earthquakes in 2024 had magnitudes of less than 4.0. On 22 April, a magnitude-3.8 earthquake hit near Concise in the canton of Vaud, which was felt not only in the epicentral area but also as far away as Lausanne and Bern. On 9 May, there was a magnitude-3.7 earthquake to the west of Lac de Dix in the canton of Valais. Another quake followed on 26 June near Schilthorn in the canton of Bern, this time with a magnitude of 3.5. Whereas the Schilthorn quake was only felt locally, the tremors of the quake near Lac de Dix were distinctly felt in the southern valleys of Valais and on the soft sedimentary soils of the Rhone Valley as far away as Brig. In all, around 1,000 reports of this quake were received from the public. Other earthquakes that were felt locally occurred as part of the Réclère sequence (canton of Jura), near Sörenberg (canton of Lucerne), near Arosa (canton of Grisons), near Fribourg (canton of Fribourg), near Martigny (canton of Vaud) and in the Val Bavona (canton of Ticino) and had magnitudes ranging from 2.8 to 3.4.
Available for download
Graphics
Number of earthquakes with magnitudes of 2.5 or greater per year
Maximum magnitude measured per year
All recorded earthquakes from 1975 to 2024 and the historical earthquakes in Switzerland