Seismic station maintenance tour

22.8.2019
Sation maintanace teams are on the road in summertime.

In Finland we have a bit over fifty permanent or semi-permanent seismic stations. Most of the stations are maintained by the University of Helsinki Institute of Seismology. University of Oulu is responsible for close to ten stations in the northern Finland and Åland station is a part of the Swedish National Seismic Network. Station maintenance is preferably done in summertime. Once properly installed,a seismic station can operate years without a need to visit it. Software updates and other operations related to the registrating devices can be done via mobile connections. But anything can happen, and quite often does. Lightning strikes, small animals interfere measurements or something simply breaks down, and our maintenance team is once again on the road.

Laboratory engineer Pirita Seipäjärvi and seimologist Tommi Vuorinen just returned from a nine day journey to Kalajoki. They inspected and calibrated all stations of the Pyhäjoki network and also Tornio station, which is a part of the Finnish National Seismic Network (FNSN) . Pyhäjoki network complements the FNSN data on the Bothnian Bay area. Its data is used to research possible active faults in the area.

Pyhäjoki network is arranged around a planned nuclear power plant location in Hanhikivenniemi. When making research on a certain area, geometry of the station network is critical. The stations should be around the area of interest. On the coastal area the sea is obviously a limiting factor. Our scientists have access to the data from Swedish stations on the other side of the Bothnian Bay, but those stations are too far away to detect small events. Swedish coast is more than a hundred kilometers to the west. Thus we have installed one station on the westernmost island of the area, Ulkokalla.  

Ulkokalla station is the most inaccessible seismic station in Finland. It takes almost an hour to drive there on a boat. Landing is not possible when weather is bad. On the other hand, it is a really beautiful place. It has not been difficult to find volunteers to travel to Ulkokalla.

Field trips in summertime are a nice change to otherwise quite office and computer oriented work. And in November, when its cold and rainy, it is actually nice to be in our warm office and analyse seismic data from Ulkokalla.