Focal depths of earthquakes in the Baikal region: A review

• Published in: Izvestiya. Physics of the solid earth Vol. 46; no. 3; pp. 216 - 229
• Main Author: Radziminovich, N. A.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01.03.2010; Springer Nature B.V
• Subjects: Earth and Environmental Science; Earth Sciences; Earthquakes; Geophysics; Geophysics/Geodesy; Regions; Research methodology; Seismology; Baikal Mountains; location of hypocentres; source depth; Baikal rift zone; earthquake
• ISSN: 1069-3513; 1555-6506
• DOI: 10.1134/S1069351310030043

Conditions and specific features in the determination of the focal depths of the earthquakes in the Baikal region are considered. Particular attention is given to the procedure of relocation of the hypocenters in accordance with the programs based on the method of minimization of rms residuals in the seismic wave traveltimes, which is widely used at present. The advantages and shortcomings of this approach are demonstrated. The available determinations of the source depths are reviewed, and examples for the interpretation of the results are presented. The averaged depth distribution of the hypocenters shows that the strongest seismic activity is observed in the depth range 10–20 km. The bottom of the seismically active layer corresponding to the level, above which 90% of sources are located, lies at a depth of 25 km. The trend of the deepening of seismic sources is observed at the northeast flank of the rift zone, where seismic activity involves the lower part of the crust.