Problems of Engineering Seismology: article

Seismic activity and the crust and upper mantle structure in the focal zones of strong Altai and Sayan earthquakes
O. Aptikaeva
Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
Journal: Problems of Engineering Seismology
Tome: 44
Number: 2
Year: 2017
Pages: 17-34
UDK: 550.344
DOI: 10.21455/VIS2017.2-2
Keywords: coda waves, Q-factor, spatiotemporal variations, attenuation field
Аnnotation: The results of the study of the field of shear wave attenuation in the focal zones of the 2003 Chui, 1970 Ureg-Nursk, 1991 Busingol, 2011 Sayan and 2011-2012 Tuva earthquakes are presented. The attenuation field within these focal zones includes blocks with a high Q-factor and linear weakened zones. During the main shock, surface ruptures of the 2003 Chui and 2011-2012 Tuva earthquakes are confined to the zones of strong attenuation. The epicenters of the main shocks are located in the zones of maximally contrasting attenuation. Zones that are similar to the «seismogenic bodies» described in the published literature are found in the focal areas of the Altai and Sayan main earthquakes or them vicinity. They tend to the linear zones of strong attenuation and are characterized by an increased density of deepened events, as well as strains of near vertical elongation. The data obtained do not exclude the participation of the «fluid» factor in the strong Altai and Sayan earthquakes scenarios.