from the focal mechanism data for the Kultuk earthquake of August 27, 2008 (Mw = 6.3) and its aftershocks.
The source parameters of the main shock were determined by calculating the seismic moment tensor. The focal
mechanism solutions of 32 aftershocks (Mw
2.3) were obtained through the deployment of a local seismic network at South Baikal. It is found that the main shock and first aftershocks (August–September) gave rise to
the activation of latitudinal fragments of the segmented near-edge fault, and the sources of the consequent after-
shocks were dominated by the NW-striking planes related to the small intrabasin structures. The calculations of
seismotectonic deformations based on the data on the focal mechanisms of the earthquakes show that the area of
activation is dominated by the transtension regime (with deformation in the form of extension with shear). The
epicentral and hypocentral fields of the aftershocks and the mechanisms of their sources reflect the complex tec-
tonic structure of the source zone of the Kultuk earthquake, which exhibits a clear subvertical zonality of the local
seismically active volume and a wedge-shaped area of crustal destruction.