Switzerland has not suffered any major earthquakes in recent decades, which explains why the population does not have a collective memory of such events and is often unaware of the danger. No other natural event can cause such a large catastrophe in a matter of minutes and have such a serious impact on the population and its livelihood. Just because they are rare does not mean that the risk is not there. The more years pass, the higher the probability of an earthquake occurring.
Every year in Switzerland, nearly 1,200 earthquakes are recorded. Most are tiny. Although all parts of our country can be affected, the canton of Valais is the region most at risk of being shaken by a large earthquake. On January 25, 1946, a magnitude 5.8 earthquake shook the Sierre region. It killed four people and damaged some 3,500 buildings.
If such a disaster were to occur today, with the rapid expansion of the housing stock and the increase in population, the number of victims would be extremely high. Historically, it has been shown that a major earthquake will probably hit a region of the Valais causing significant damage within a radius of around 15 kilometres of its epicentre within the next 25 years. Moreover, buildings dating from the 1970s, a boom period in this region, are not very resistant to the stresses created by an earthquake.
Today, earthquakes are fairly well understood, but it is still impossible to predict where, when and with what intensity an earthquake will strike. Current scientific knowledge does not make it possible to give an alert early enough before the arrival of the destructive waves of the earthquake, particularly with a view to evacuating people from their homes.
« What does logic tell us? We cannot predict an earthquake, so we must prepare for it in order to minimise its effects on the population of our country »
We will never be able to prevent earthquakes. This does not mean, however, that we are totally powerless in the face of an event of such magnitude: we can limit the damage through information, training, preparation and precautionary measures.