Following the production tests at the start of November, the St. Gallen public utilities company (Sankt Galler Stadtwerke) completed the first phase of their geothermal energy project. It is currently evaluating the collected data and will determine the further course of action based on the results. The Swiss Seismological Service (SED) is likewise using this as an opportunity to take a look back, and presents an overview here of the findings obtained thus far.
Read more...As expected, earthquake activity in St. Gallen decreased steadily following the magnitude 3.5 earthquake on July 20, 2013. During preparations for the production tests, however, an increasing number of microearthquakes occurred since September 16, 2013. During this period, a total of 232 microearthquakes were recorded. The strongest took place on October 2, 2013, and had a magnitude of 2.0. With the start of the production tests on October 15, 2013, during which gas and water were extracted from the subsoil, earthquake activity decreased considerably. Since that time, the SED has recorded only four very weak events. These microearthquakes may have been aftershocks from the October 2, 2013, earthquake, and are thus not necessarily directly related to the production tests.