Last year, twice as many earthquakes occurred in Switzerland and in neighbouring countries compared to the long-term average. For nearly 50 of the total of 1,670 recorded earthquakes, the Swiss Seismological Service (SED) at ETH Zurich received five or more felt reports. Most of the quakes can be attributed to five active earthquake sequences that shaped seismic activity in 2019. One of them was in the canton of Valais, in the area between Anzère and the Sanetsch Pass. The other four occurred just over the Swiss border, at Courmayeur (Italy), Novel (France), Konstanz (Germany) and Chamonix (France).

In Switzerland, earthquakes often occur in sequences referred to as 'earthquake swarms', i.e. clusters of tremors occurring over time at one, specific location. An unusual feature of last year's seismic activity was the number of highly active earthquake sequences leading to a never previously recorded amount of events since modern seismic monitoring began in the 1970s. This also resulted in more felt earthquakes than usual. As a rule, quakes felt by humans have usually a magnitude of 2.5 or more. The last time a similar cluster of felt quakes occurred was back in 1964, when Sarnen, in the canton of Obwalden, experienced a distinct sequence of earthquakes over a period of several months, with magnitudes of up to 5.3. Although such a high level of earthquake activity as that experienced in 2019 is rare, it is neither unexpected, nor a sign of an increased seismic hazard over the months and years to come.

One memorable event of the past year was undoubtedly the earthquake swarm that occurred north of Sion in Valais in November. So that was the inspiration for this year's Christmas card. The baubles on the Christmas tree represent the numerous quakes of the swarm, and the mountain range behind it represents the cumulative number of tremors. Click on the impage for a detailed view.

The Sion earthquake swarm took place in a region historically known for its seismic activity and where numerous small and occasionally larger quakes can also be expected in the future. There is no way of predicting exactly how seismic activity will develop there, but analysing the extensive data provided by this earthquake swarm is helping us gain a clearer understanding of earthquake activity in the area.

We wish you a very Merry Christmas and a happy and instructive New Year!

Am Samstag, den 30. November 2019, ereignete sich um 03:14 Uhr (Ortszeit) ein Erdbeben der Magnitude 3.0 in einer Tiefe von ca. 2 km östlich von Verbier (VS).

Das Erdbeben wurde weiträumig verspürt, insbesondere im Rhonetal, wo die weichen Sedimente die Erdbebenwellen verstärkten. Beim SED gingen in der Stunde nach dem Beben etwa 200 Verspürtmeldungen ein. Bei einem Erdbeben dieser Stärke sind keine Schäden zu erwarten.

Das Wallis ist der erdbebenreichste Kanton der Schweiz. Die Region südlich des Rhonetals ist dabei im Allgemeinen weniger aktiv als die Region nördlich der Rhone, wo sich im November ein Erdbebenschwarm mit über 300 Erdbeben ereignete, wovon über ein Dutzend verspürt wurden. Das aktuelle Beben hat keinen kausalen Zusammenhang mit diesem Erdbebenschwarm.

Der Erdbebenschwarm nördlich von Sion (VS) ist nach wie vor aktiv. In den vergangenen sieben Tagen haben sich über 100 weitere Beben ereignet, womit die Gesamtzahl der aufgezeichneten Ereignisse aktuell bei mehr als 300 liegt. Für die Bevölkerung waren in diesem Zeitraum zwei weitere Beben spürbar. Sie ereigneten sich am 11. und 12. November 2019 und wiesen eine Magnitude von 2.7 auf. Mit aktuell 16 verspürten Beben weist der Erdbebenschwarm eine ungewöhnliche Häufung an Erschütterungen auf, die genug stark sind, um von der Bevölkerung wahrgenommen zu werden. Wie sich der Erdbebenschwarm weiterentwickelt, bleibt weiterhin unklar. Es kann zudem nach wie vor nicht ausgeschlossen werden, dass sich ein stärkeres Beben ereignet.

In Switzerland, earthquakes are the natural hazard with the greatest potential for causing damage. They cannot currently be prevented or reliably predicted. But, thanks to extensive research, much is now known about how often and how intensely the earth could shake at a given location in the future. Consult a variety of different maps using our interactive web tool to find out how likely certain earthquakes are in Switzerland.

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The Swiss Seismological Service (SED) at ETH Zurich is the federal agency responsible for monitoring earthquakes in Switzerland and its neighboring countries and for assessing Switzerland’s seismic hazard. When an earthquake happens, the SED informs the public, authorities, and the media about the earthquake’s location, magnitude, and possible consequences. The activities of the SED are integrated in the federal action plan for earthquake precaution.

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