Seismotectonic Deformation of Active Segments of the Junction Zone of the Kolyma–Omolon Superterrane and South Anui Suture (Southeastern Russia)

Abstract

Our seismotectonic studies focus on active segments of the junction zone of the Kolyma–Omolon superterrane and the South Anui suture. The aim of our research is to identify features that show activation of suture zones and to determine the parameters of the stress–strain state of the crust in the study area. The analysis was based on the average seismotectonic deformation tensors, which were estimated for the main epicentral fields of Russia’s northeastern regions. New data are now available on the focal characteristics of moderate earthquakes, which can improve determination of the kinematic types of junctions of suture zones of the tectonic taxa located along the Arctic and Pacific continental margins. Seismotectonic crustal destruction regimes are determined for the active segments of the junction zone of the Kolyma–Omolon superterrane and the South Anui suture. These regimes are influenced by global geodynamic processes taking place at lithospheric plate margins, as well as by the dominant deformation fields of adjacent tectonic taxa. The seismotectonic analysis results suggest activation of the suture zones of the northwestern flank of the Kolyma–Omolon superterrane under stable north-eastward compression. The suture zones may extend into the Laptev Sea area, where they are conjugate with the structural elements of the South Anui suture (Novosibirsk–Svyatoi Nos segment). In the Anui–Chukotka segment of the suture, seismotectonic crustal destruction changes from compression to extension. This is due to the effect of deformation fields of active megazones of conjugated tectonic taxa of the Novosibirsk–Chukotka fold-and-thrust and Okhotsk–Chukotka active margin zones. For the tectonic taxa of the Arctic sector of Russia’s northeastern regions, a database has been consolidated, including the of seismotectonic crustal deformation parameters, which may be useful for various geodynamic reconstructions.