2019-11-06
Ongoing earthquake swarm north of Sion (VS)
[updated 11/06/2019, 07:30]
Starting in the night of 4 to 5 November, 2019, an exceptionally active earthquake swarm is ongoing near Savièse, north of Sion VS. Until the morning of 6 November, the seismic network of the Swiss Seismological Service at ETH Zurich (SED) has recorded more than 100 events. Twelve of these had magnitudes of 2.5 or larger and were widely felt by the population of the Sion region up to Sièrre. The four strongest quakes reached magnitudes between 3.0 and 3.3 and were sporadically felt even in the Bernese Oberland. Overall, the SED has collected several hundred felt reports on its website.
Such an accumulation of earthquakes is rather untypical for Switzerland. Earthquake swarms with many events within days or weeks happen regularly. However only rarely as many perceptible earthquakes occur within a small period of time. Still, predicting the future development of this sequence is not possible. Typically, the seismic activity decays after days, at most after weeks. However, there is a probability of 5 to 10 percent for significantly stronger earthquakes to occur within the next days.
Read more...The Valais is the most active earthquake region of Switzerland. The quakes of these days took place in one of the most prominent zones of activity which extends south of the Diablerets and Wildhorn massifs in parallel to the main valley. The last felt event in the area before the beginning of the current sequence was on January 14, 2018, however small, instrumentally detectable earthquakes are observed nearly on weekly basis. The last strongly damaging quake in Switzerland, a magnitude 5.8 which occurred on 25 January 1946, happened also near the Wildhorn and caused considerable damage in an expanded area.
