Additional info:
The seismic swarm began in the Nový Kostel region in West Bohemia on 23.8.2011. Seismological stations operated by the IPE recorded hundreds of earthquakes of this swarm with magnitude 1.0 and greater.
The earthquake was felt by people near the epicentre with intensity IV on the EMS-98 macroseismic scale. If you felt it too you can report your experience here.
It presented no threat to any of the Czech NPPs.