In the Otaniemi geothermal project of St1, the measurement network installed in the bedrock of the Helsinki Metropolitan area discovered in the afternoon on 17 May a 1.2 magnitude micro-earthquake in the deep bedrock.
The effects of this magnitude have been detectable at ground level in the surrounding areas for example in the form of sound and sound waves can also resonate e.g. in windows and structures, but do not cause a risk to humans or damage structures.
St1 implements the seismic monitoring according to the measures required by the authorities. We communicate all micro-events exceeding 1.2 magnitudes at our project website.
The effects of the measures are closely monitored in co-operation with the Institute of Seismology of the University of Helsinki. The Institute of Seismology has monitored 0.6 magnitude micro-event. The differences in the measurement result is due to differences in measurement methods and equipment. The St1 equipment is tuned to detect earth movements as accurately as possible.
The Otaniemi geothermal pilot project has progressed to the finalization of the heat wells, which includes hydraulic tests and counter-stimulation. This project stage ensures that the water supplied to the system flows as well as possible in the rock fracture between the wells.
Potential micro-earthquakes can occur at different times of the day with hydraulic tests, counter-stimulation and preparatory work in progress during the weeks 17 - 21.
We apologize for the inconvenience caused by us.
Up to date information can be monitored online www.st1.eu/geothermal-heat
All seismic events in Finland and adjacent areas can be monitored at the Institute of Seismology www.seismo.helsinki.fi/bulletin/list/alert/current_map.html
If you have made earthquake observations yourself, you can report them to Institute of Seismology using the observation form: https://elomake.helsinki.fi/lomakkeet/89816/lomake.html