The Ust’-Barguzin Transfer Zone (Central Baikal): Seismological Evidence on the Transtensive Stress Field of the Crust

Abstract

According to seismological and geodetic data, the central part of the South Baikal basin is under an extension regime of the Earth’s crust. This study presents for the first time seismological evidence of a transtensive stress field in a local area adjacent to the eastern side of the Central Baikal subbasin. Two independent approaches to determining the orientation of the principal stress axes show a subhorizontal orientation of the axes of stresses of minimum and maximum compression, which results in a strike–slip component in the focal mechanisms of the earthquakes. The area under consideration is a part of the Ust’-Barguzin transfer zone, in which the transfer of deformations between South Baikal and the Barguzin basin takes place. The results obtained are in agreement with the geological and structural data and may indicate the contribution of horizontal displacements in the transfer of deformations between the segments of the rift zone.