As reported in the journal Nature , the authorities of the Swiss canton of Nidwalden have prepared an emergency plan to deal with the consequences of a tsunami. Wait, a tsunami in Switzerland?
Yes, because this devastating phenomenon is not only triggered in the oceans : in 1971, a gigantic wave in the Peruvian lake of Yanawayin killed between 400 and 600 people.
Although the alpine country is not as seismically active as Peru, experts have calculated, for example, that every millennium there is an earthquake of magnitude 6 on the Richter scale in the vicinity of Lake Lucerne.
A few days ago, the geologist Katrina Kremer presented her conclusions on the sediment studies that she had carried out in another Swiss lake: that of Geneva. Based on samples collected by his team at a depth of 30 meters, Kremer believes that this lake has experienced up to five tsunamis in the last 4,000 years.
The strongest of them all, dating from 563 , apparently originated from the fall of part of a mountain on the Rhone river delta. The impact raised waves some eight meters high and washed away the old town of Geneva.
But you don’t have to go back so long.
Lake Lucerne also suffered two such events in the 17th century. The first took place in 1601 probably as a result of an earthquake that displaced the accumulated sediments in its depths.
For this reason, faced with the contingency that another earthquake or landslide will once again shake the waters of the now placid lake, the political leaders of the canton of Nidwalden have commissioned a group of experts from the University of Bern to draw up maps of possible floods . Your observations will serve as a guide in establishing evacuation plans and erecting future construction.
