Role of the seismic focal zone in the formation and development of the Kuril-the Sea of Okhotsk region structures
A model of the seismic focal zone is presented to explain formation and functioning of the seismic focal zone based on the near-surface compressive stresses acting at the continent-to-ocean boundary and dislocation theory. The magmatic chambers are shown to be confined to the areas where seismic focal zone crosses the lower viscosity asthenospheric layers located at the depths of 60-80, 120-150 and 220-300 km. Morphological and tectonic features of the different elements of the Kuril - the Sea of Okhotsk Region are examined. The Greater and Lesser Kuril Ridges were found differing markedly in functioning time inferred from geophysical fields and geological-petrographic composition.