Seismicity pattern and thermal anomalies in the southern Baltic region before and during the Kaliningrad earthquakes of 2004

Abstract

The seismic situation in the SE Baltic region that existed during the period 1990–2006, including the unexpectedly strong Kaliningrad earthquakes of 2004, is analyzed. The spatiotemporal variation of seismic events in the region is examined on the basis of a newly compiled catalog of tectonic earthquakes. The analysis revealed outbursts of seismic activity in 1995 and 2004, structurization of the distribution of shocks, and their southward migration. The distribution of hot springs that arose in 2002–2004 is analyzed in relation to seismological data. The seismic process and thermal anomalies are shown to be geodynamically controlled, which provided constraints on the nucleation process and focal mechanism of the Kaliningrad earthquakes. The region, located in the western East European platform, should be regarded as seismically rather active.