Palaeoseismic deformations in the Eastern Baltic region (Kaliningrad District of Russia)

The article presents new data on sedimentological structures, which have been discovered at the Ryadino archaeo­logical excavation in the northeast of the Kaliningrad District of Russia (the Šešupė River Valley). Tongue-shaped and dome-shaped diapir-like structures indicate liquefaction-induced features. As the most plausible reason, the earthquake-induced shaking is discussed. A preliminary estimation of the time interval for the seismic event covers the period from the early up to the late Holocene. The reasons for seismic activity in this region can be related to neotectonic movements (including glacio-isostatic rebound) as recorded in the southeastern Baltic Sea area of the Fennoscandian ice sheet margin zone. The relation between a palaeoseismic event and the essential changes in the hydrographic network in the region is also discussed.