ИСТИНА

The article considers the results obtained by IFZ RAS staff from observations of GPS/GLONASS (GNSS) for studying the modern regional geodynamics of the Russian part of Fennoscandia and surrounding territories for 2006-2018. Horizontal displacements of GNSS sites in Fennoscandia have an average rate 19.9 mm/year and NE direction in the North of the region and up to 23.9 mm/year in the South. Vertical movements display the dome uplift up to 10.4 mm/year (no more than 5-6 mm/year in the Russian territory). Intra-regional velocities of horizontal displacements, predominantly by SE direction, range from 0.8 mm/year in the North-West to 5.8 mm/year in the South-East. The deformation field of the region is uneven, and extended zones of compression and extension replace each other. The values of the deformation varies from -0.8·10-8 to 1.6·10-8 per year. Anomalous manifestations of the deformation field were detected for the coast of the Western part of the Gulf of Finland and the coast of the Kandalaksha Bay. To assess the seismic activity of the studied region, the seismic energy flow PE was calculated. Its distribution is not uniform within the area under consideration. A more intensity of seismic manifestations is inherent to the Fennoscandia dome uplift. Seismic activity in the western part of the region appears as an arranged chain of fragments of meridional orientation with PE up to 1010J/year; one of them is confined to a zone with extension up to 0.6·10-8 per year. The deformation of the territory was correlated with the average annual velocity of the seismic energy flow. Increased seismic activity in the Kandalaksha Bay area accompanied to the abnormal behavior of the deformation field. Baltic-Ladoga seismic activity area is stretched from the SW to the NE. The average annual changes of the of seismic energy flow PE here reach 106 J/year. This area is characterized by a transition from compression deformations to extension deformations and marks the transition zone from the dome to the platform. The results of the research using GNSS technologies and analysis of seismicity allow us to assess the modern tectonic activity of the Russian part of Fennoscandia and its characteristics in the first twenty years of the current century.