On Saturday 11 February 2012 at 11.45 pm local time (10.45 GMT), the Swiss city of Zurich was shaken by at Earthquake measured as a 4.1 on the Richter Scale at a depth of 16 km by the United States Geological Survey and as a 4.2 on the Richter Scale at a depth of 30 km by the Swiss Seismological Service. The quake took place about 14 km south of the city, and it is thought highly unlikely it will have caused any damage or serious injuries, but is was felt widely in Switzerland and southern Germany.
Map showing areas where people reported shaking, and the intensity of shaking reported. From the United States Geological Survey.
Switzerland is not generally thought of as being a seismically active country, but it records between 500 and 800 quakes every year, of which on average 10 are felt by humans. Earthquakes large enough to cause significant damage only happen once or twice a century. Earthquakes occur in Switzerland, and surrounding countries, because the Alps are not static structures, but are a growing range of mountains being forced upwards by the impact of Africa into Europe. This movement is not smooth and continuous, but bumpy and jerky, as the rocks stick to one another while pressure builds up, then release suddenly causing quakes.