Horizontal deformations of the Earth’s crust in the Baltic region from GPS data

Abstract

The NW-SE oriented Paldiski-Pskov transitional zone is characterised by stress field rotation. The identified strain rates are compatible to those obtained from other cratonic areas (e.g. Fennsocandian Shield, North America, and India). Furthermore, the domination of extensional deformations in the western and northern parts of the Baltic region correlate with the GPS data from the Fennsocandian shield. The identified pattern of the horizontal deformation is important for understanding seismic processes in the Baltic region. For instance, increased seismicity in easternmost Lithuania and adjacent Belarus is related to high compressional strain rates. Furthermore, the inversion of recent vertical movements is characteristic for the compression-dominated eastern province, as defined by precise geodetic levelling data, while no inversion is reported from extension dominated areas. A rotation of the stress field is recognized in the Kaliningrad district. Furthermore, the highest dilatational strain is measured the Kaliningrad District attaining +1.5×10-8 yr-1 and may be causally related to the strong Kaliningrad earthquakes of 2004.