As part of the planned St. Gallen geothermal energy project, test and simulation measures are currently being performed in geothermal reservoir rocks at a depth of 4,000 to 4,500 meters. The Swiss Seismological Service (SED) is monitoring this work with a dense network of six seismological stations, within the scope of the GeoBest project and in collaboration with the St. Gallen public utilities company (Sankt Galler Stadtwerke) and the Swiss Federal Office of Energy.
Read more...Since the start of the test program on July 14, 2013, the SED has, as was expected, registered several microearthquakes that could be localized near the bottom of the GT-1 deep borehole in St. Gallen. The microearthquakes are so small that they can only be recorded at the stations of the network, which was set up specifically for monitoring. A local earthquake magnitude of ML = 0.9 on the Richter magnitude scale was determined for the strongest quake, which occurred on July 14, 2013, at 12.06.35 p.m. (UTC). Earthquakes of this size cannot be felt by people.
The currently observed seismicity near the geothermal borehole GT-1 has so far been in line with expectations and, based on our assessment, poses no cause for concern. The greater St. Gallen area will continue to be monitored around the clock for seismic activity and the results provided in real time to the St. Gallen public utilities company. It is thereby ensured that the test and simulation program can be modified or discontinued if necessary in accordance with the response plan developed in advance by the St. Gallen public utilities company. The SED will continue to perform detailed seismic monitoring in the coming months.
