CURRENT STRESS PATTERN AND GEODYNAMICS OF THE BAIKAL RIFT SYSTEM
Yu.L. Rebetsky1, A.A. Dobrynina2,3, V.A. San’kov2
1Shmidt Institute of the Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
2Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
3Geological Institute, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia
Keywords: Stress, earthquake, tectonophysics, earthquake focal mechanism, fault, geodynamics
Abstract
The crustal stress field of the Baikal Rift System has been reconstructed by tectonophysical inversion of focal mechanisms from the catalog of earthquakes recorded by the regional seismological network. Cataclastic analysis of fault slip data developed at the Shmidt Institute of the Physics of the Earth (Moscow) revealed previously unknown features in the behavior of principal stresses. Namely, the maximum deviatoric stresses diverge off the rift axis while the normalized spherical and deviatoric stress tensor components reach high magnitudes in the crust of the Baikal Basin. The obtained stress pattern of the Baikal Rift System is consistent with the rift origin by a joint action of a vertical mantle flow (upwelling branch of convection) and a horizontal flow in the asthenosphere which drives the NW-SE motion of the Amur plate off Eurasia.
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