The stimulation stage has been completed on Sunday evening and the pumping of water to the bedrock has been stopped. When the water settles to the balance position, unfortunately smaller micro-events may still occur within few days. We will continue the seismic control of the area and measurements show that the activity level has dropped rapidly, as expected, and continues to decline further. The Institute of Seismology at the University of Helsinki monitors the project with its own meters and also has access to the data of the St1 measurement network in real time.
In the Otaniemi geothermal project of St1, geophones installed in the bedrock of the Helsinki Metropolitan area discovered at night 1.45 and 1.2 magnitude micro-earthquakes 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.
The Institute of Seismology has monitored the first event as 1.1 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 water movements as accurately as possible.
We communicate all micro-events exceeding 1.2 magnitudes at our project website.
Geophone measurement results as well as 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