The Bystrinskii Earthquake in the Southern Baikal Region (Sep. 21, 2020, M w = 5.4): General Characteristics, Basic Parameters, and Deformation Signs of the Transition of the Focus to the Meta-Unstable State

The results of studying the Bystrinskii earthquake of September 21, 2020, in the southern Baikal region are presented. Its geodynamic position, focal mechanism, and basic parameters are indicated. The deformation monitoring data showing six days of anomalous growth of rock deformations preceding the earthquake are provided. It is shown that the scenario of the deformation process before the earthquake is similar to the scenario of preparing dynamic slip during the experimental simulation of the intermittent “stick–slip” process. On the basis of similarity in the implementation of deformation processes in nature and in the model, it is stated that the deformation anomaly, which appeared just before the Bystrinskii earthquake, is a regular phenomenon and can be considered as its short-term precursor.