Drilling for geothermal power sources likely caused a minor earthquake early Saturday morning, which was felt across a large area of Eastern Switzerland from St. Gallen to Appenzell.
The epicentre of the magnitude 3.6 quake was registered at a depth of four kilometres. The shaking is probably directly related to test measurements and simulations currently taking place for the drilling of geothermal power plant project in St. Gallen, according to the Swiss Seismological Service (SED), based at Zurich’s Federal Institute of Technology.
Minor damage to buildings as a result of such a quake can’t be ruled out, the SED noted.
The goal of the geothermal drilling project is to find hot water (140 degrees Celsius) at about 4500 metres deep that will supply half of St. Gallen’s buildings with energy. The seismological service installed 10 measuring stations around the drilling area to monitor seismic activity, which they expected to be weak but consistently present.
Numerous small earthquakes were already produced over the past few days because of the drilling, and their intensity increased overnight Friday. More tremblers could be felt as the project continues.
In Basel, drilling was stopped in 2006 in a similar project because of the risk of seismic activity. The project was eventually called off in December 2009 following a series of earthquakes, the largest of which registered 3.4 degrees on the Richter scale.