Crustal Stresses in the East Arctic Region From New Data on Earthquake Focal Mechanisms

Abstract

East Arctic is a key region for understanding the current geodynamic pattern and lithospheric evolution of the whole Arctic. To close an evident gap in regional seismic data, we calculate source parameters for 103 earthquakes (Mw ≥ 4.2, 1990–2021) and compile a representative uniform dataset including source depths, scalar seismic moments, moment magnitudes, and focal mechanisms. On its basis, crustal stresses are estimated within four blocks with the homogeneous stress field. Extension dominates along the Gakkel Ridge and over most of the Laptev Sea shelf. On the continent and east and west of the shelf, it is replaced by compression. The obtained results indicate that the spreading axis of the Gakkel Ridge does not continue to the Laptev Sea shelf and evidence for the Eurasian–North American plate boundary crosses the eastern Laptev Sea shelf and is likely to pass to the Chersky Range through the Yana Bay.