Model of tectonic stress in the Eastern Baltic region

The parameters and mechanisms of the source of modern earthquakes in the Eastern Baltic region are systematized. The predominant types of focal mechanisms of continental earthquakes are strike-slip and reverse. A generalized map of the orientation of maximum horizontal stresses in the East Baltic region and adjacent territories has been created. To create this map, we utilized the World Stress Map database and added the directions of maximum horizontal stresses in Estonia. The direction of maximum horizontal stresses changes from north (Estonia) to south (Kaliningrad region of Russian Federation) from 102º–114º to 157º–166º. The study investigated how the deep geological structure and gravitational forces in different parts of the earth's crust affect the direction of maximum horizontal stresses. It was observed that the direction of maximum horizontal stress changed when crossing only one of a deep tectonic fault. The direction of maximum horizontal stress showed the high correlation values with the gravitational effect of the sedimentary cover (negative correlation), the averaged difference gravitational field, and the gravitational effect of the crustal layer up to the Conrad boundary.