Problems of Engineering Seismology: article

Central Baikal crustal block velocity model definition using the data of Kudarinsky earthquake
A.V. Belyashov
Trofimuk Institute of Petroleum Geology and Geophysics of the Siberian Branch of the Russian Academy of Sciences
Journal: Problems of Engineering Seismology
Tome: 51
Number: 1
Year: 2024
Pages: 5–17
UDK: 550.34.06.013.3, 550.34.06.013.24
DOI: 10.21455/VIS2024.1-1
Keywords: Kudarinsky earthquake, Central Baikal, three-dimensional velocity model, aftershocks
Аnnotation: Using an adjusted technique the position of the Kudarinsky earthquake aftershocks was relocated, the main part of them are placed in the depth interval from 20 to 25 km. Inverse correlation dependence of the VP/VS parameter from the aftershocks hypocenter depth was defined. Basing on the P-and S-waves records processing three-dimensional velocity model of the Central Baikal crustal block 250×230×36 km in size was built. In the velocity section revealed the area up to 10–12 km thickness with reduced velocity values (1.9–5.3 km/s for Р-waves and 1.1–3.0 km/s for S-waves), that is associated with sediments of Selenga river delta and Baikal lake South basin. In the central part of the investigated block at the depth of 6–8 km the top of crystalline basement with P-wave velocity of 6.0 km/s defined. Analysis of the Poisson coefficient field shows that the main part of the aftershocks concentrated in 0.22–0.24 range. Basing on the revealed velocity features of the Central Baikal crust the initial velocity models will be updated with the purpose of local earthquakes more precise localization.