Swedish National Seismic Network (SNSN). A short report on recorded earthquakes during the second quarter of the year 2011

According to an agreement with Swedish Nuclear Fuel and Waste Management Company (SKB) and Uppsala Univ., the Dept. of Earth Sciences has continued to carry out observations of seismic events at seismic stations within the Swedish National Seismic Network (SNSN). This short report gives brief information about the recorded seismicity during April through June 2011. The Swedish National Seismic Network consists of 62 stations. During April through June, 2,160 events were located whereof 129 are estimated as real earthquakes, 1,502 are estimated as explosions, 310 are induced earthquakes in the vicinity of the mines in Kiruna and Malmberget and 219 events are still considered as uncertain but these are most likely explosions and are mainly located outside the network. Two earthquakes had magnitudes above ML = 2.0 during the period. In May one earthquake with magnitude ML = 2.8 was located in Kattegatt, 31 km SW of Falkenberg and in April an earthquake with magnitude ML = 2.0 was located 19 km NW of Robertsfors. Additional 16 earthquakes had magnitudes equal to or above ML = 1.0.