Late Cenozoic fault pattern and stress fields in the Barguzin rift (Baikal region)

Abstract

New structural and tectonophysical data, combined with the published geophysical and seismological evidence, were used to map the Late Cenozoic fault pattern and crustal stress in the Barguzin rift. Faults striking in the NE direction are the most abundant elements of the rift structure. A special part in the Late Cenozoic patterns of faults and stresses belongs to an over 400 km long N-S lineament which shows up as a system of separate fault segments between 110° and 110°30′ E. The Late Cenozoic evolution of the rift has been controlled mainly by extension punctuated with local shear stresses derived from the regional extension stress and accommodated by strike slip, combined with the dominant normal motion, along NE or N-NE faults and/or along their cross faults. Extension was of a relatively stable NW-SE direction, almost rift-orthogonal. The obtained fault pattern and stress maps can be used for reference in mapping seismic hazard associated with ongoing faulting in an active and changeable stress field.