Recent Intraplate Seismicity in Estonia, East European Platform

Abstract

Abstract Four Estonian earthquakes were studied, 1.2–2.0 in magnitude and taking place in 2016–2018. Their focal parameters were determined, providing an opportunity to place them in the context of the regional stress field and make tentative geological interpretation of their connection to faults in the Precambrian basement, which is overlain by a 100–600 m thick sequence of sedimentary bedrock. Such research was made feasible by augmenting the permanent three-station Estonian seismic network with seven temporary stations. The analyzed earthquakes were compared with the largest known Estonian earthquake, the 1976 magnitude 4.5 Osmussaar earthquake. The results indicate that it is possible to consider all the five events as expressions of predominantly left-lateral strike-slip movement on north-northwest–south-southeast subvertical faults in concert with the general stress field of northern Europe, which is dominated by plate movement.