2026-01-29
Earthquake activity in 2025
Up to now, 2025 saw the second highest number of earthquakes ever recorded in Switzerland and neighbouring regions, at just over 1,800. The most powerful events focused attention on regions not primarily associated with earthquakes, reminding us that the whole of Switzerland is an earthquake country.
The strongest earthquake last year occurred on 21 July near Mürren (canton of Bern). It had a magnitude of 4.2 and was accompanied by several foreshocks and aftershocks. The hypocentre was close to the Earth's surface. This meant that the earthquake was felt strongly in the epicentral area and only weakly further away. Of the approximately 700 felt reports received by the Swiss Seismological Service, the majority came from the Lauterbrunnen and Kander valleys and the area around Lake Thun. There were isolated reports from as far away as the Basel and Zurich regions. Earthquakes had already occurred in the same area the previous year. The series of earthquakes near Mürren indicates a shallow, active thrust fault on the northern edge of the Aar Massif. It is probably related to ongoing tectonic processes in and around the Aar Massif and its geological uplift history during the formation of the Alps. Like the quake in Ochsenboden in 2024 (canton of Schwyz), the earthquakes near Mürren reflect the ongoing deformation of the Helvetic nappes. They show that, while the majority of earthquakes in Switzerland occur at greater depths of 5 to 20 kilometres, tectonic stresses can also act on faults in the rock relatively close to the surface and are discharged in the form of earthquakes.ound Lake Thun. There were isolated reports from as far away as the Basel and Zurich regions. Earthquakes had already occurred in the same area the previous year. The series of earthquakes near Mürren indicates a shallow, active thrust fault on the northern edge of the Aar Massif. It is probably related to ongoing tectonic processes in and around the Aar Massif and its geological uplift history during the formation of the Alps. Like the quake in Ochsenboden in 2024 (canton of Schwyz), the earthquakes near Mürren reflect the ongoing deformation of the Helvetic nappes. They show that, while the majority of earthquakes in Switzerland occur at greater depths of 5 to 20 kilometres, tectonic stresses can also act on faults in the rock relatively close to the surface and are discharged in the form of earthquakes.
Quakes felt in supposedly quiet regions
Earthquakes of this magnitude and even larger earthquake swarms are not unusual for the Bernese Oberland. The quakes near Herisau (canton of Appenzell Ausserrhoden) on 6 December and Affoltern am Albis (canton of Zurich) on 30 July, which were also strongly felt locally, are nothing out of the ordinary either. With magnitudes of 3.1 and 3.0 respectively, they illustrate that earthquakes occur repeatedly even in seismically less active areas. They are the result of ongoing shifts along various fault zones in the crystalline bedrock of the Molasse Basin area, which extends across the Swiss Plateau. The second largest earthquake in 2025, which occurred on 2 September near Lake Resia (South Tyrol, Italy) not far from the Swiss border, was only felt in the Engadine and Davos regions, although it was considerably stronger with a magnitude of 3.8.
Last year saw a total of 28 earthquakes with a magnitude of 2.5 or greater. Most quakes of this magnitude can be felt by the public. The number of such earthquakes was slightly above the average for the past 50 years, which stands at 24.
Many earthquakes due to swarms
As in previous years, several earthquake swarms contributed to the high number of recorded quakes. The area around the Grandes Jorasses in the Mont Blanc Massif was once again particularly active, with around 400 earthquakes recorded. The activity there follows a previously observed seasonal pattern, with an increase in seismicity in autumn. This is thought to be due to the growing impact of climate change in high mountain regions. Heatwaves are causing permafrost to thaw and are accelerating glacier melt. This is altering meltwater infiltration pathways, thus affecting the pore water pressure all the way down to deep rock formations and changing the stress regime in the subsurface. These processes are reflected in increased seismic activity in regions where less earthquake activity had previously been observed (see "Glacier melt increases seismic activity under the Mont Blanc Massif").
The earthquake swarm near Réclère (canton of Jura) also continued, with 100 recorded quakes, but weakened towards the end of the year. The measurement network has been locally densified, enabling detailed characterisation of the swarm and providing important information about the tectonic processes on the northern edge of the Jura Mountains. Further swarms occurred in the Pennine Alps, near Fribourg (canton of Fribourg), in the German border region of Hegau and near Aosta (Italy), among other places.
Other signals from explosions and mass movements
As well as earthquakes, the seismic network recorded over 400 blasts in quarries last year. In addition, 41 mass movements were automatically recorded (see list of mass movements). Of these, 31 were externally confirmed as landslides or rockfalls. The biggest of these events was the catastrophic glacier collapse on the Kleines Nesthorn, which destroyed the village of Blatten (canton of Valais) in May.
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Graphics
Number of earthquakes with magnitudes of 2.5 or greater per year
Maximum magnitude measured per year
All recorded earthquakes from 1975 to 2025 and the historical earthquakes in Switzerland