Neotectonics of the Barents Sea Shelf Eastern Part: Seismicity, Faults and Impact of the Atlantic–Arctic Rift System

This study analyzes seismicity within the shelf of the Barents Sea and the Knipovich and Gakkel ridges that surround it, and compares the spatial distribution of seismicity with the fault network as identified by seismic prospecting data. Kinematic characteristics have been obtained for the spatial migration of seismic activity. It is shown that the seismic events recorded by NORSAR, the Norwegian regional network, as occurring within the Russian part of the Barents Sea shelf make linear clusters along strike slip faults. The fault network displaces Mesozoic seismic sequences and emerges at the bottom surface by displacing Quaternary deposits. This clearly indicates a present-day age of the faults along which the linear clusters of low magnitude seismicity aligned. The computation of the total seismic moment in the space-time domain showed the presence of a seismic activity migration along short fault segments in the shelf at rates of 10.5 to 25.7 km/year. A burst of general activity in the shelf area beginning in 2012 could be noted. Comparison of the time-dependent evolution of seismic activity in the shelf to fragments of the Atlantic–Arctic Rift System suggests that the evolution is due to tectonic deformation waves that are initiated along the geodynamically active plate boundary and are propagating to the shelf at a rate of 20‒22 km/year. Another alternative, namely, that the rate of migration can reach 77 km/year, is less likely. The increase in the rate of seismic activity in the shelf after 2012 might be, not emission due to the excitation of a slow deformation wave, but rather resulted from direct triggering impact on the shelf by the Knipovich and Gakkel ridges.