Seismotectonic Activation of Modern Structures of the Siberian Craton

Abstract

Our research of the modern structures of Siberian Craton aims to reveal regional regularities in the seismotectonic destruction of the Earth’s crust and to clarify the dynamics of the formation of the focal zones of strong earthquakes. Analysis of activated structures and marginal suture zones located in the study area was based on structural and geophysical data, the modern structural plan, and the quantitative characteristics of modern and recent tectonic movements, active faults, and tectonic stress fields identified by tectonophysical analysis of deformation and seismological parameters. Unambiguous correlation between the seismic activity level of modern structures and the rates of modern and recent tectonic movements were not determined in our study. The most active structures of the Siberian Craton located in zones of the dynamic influence of marginal sutures are contrasted against the gradient field of modern vertical tectonic movements and characterized by the mosaic field of the mean and low rates of modern movements. The kinematics of seismotectonic deformation and levels of seismic activation of suture zones of the Siberian Craton are governed by global geodynamic processes taking place at the boundaries between the Eurasian, North American and Amur lithospheric plates. The activated structures in the northern regions of Siberian platform, which are characterized by the highest rates of modern movements, are heterogeneous. Both fluid processes and glacioisostatic movements may have influenced the dynamics of the formation of these high-gradient deformation zones. In seismotectonic studies aimed at determining levels of the potential seismic hazard of modern structures, we find it important to take into account errors in geodetic data and ensure more correct reference to the rates of tectonic movements at the neotectonic stage. In order to correctly assess the degree of geodynamic activity of modern structures, special consideration should be given to the fluid-geodynamic factor that controls most geodynamic processes, including tectonic stress accumulation, the formation of earthquake focal zones, and the intensity of seismic events.