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Object of research. The mathematical apparatus of the theory of fractals and the algorithms developed within its framework are used to assess the statistical self-similarity of the fields of epicenter earthquakes in the Baikal region.Materials and methods. The solution is implemented on numerical models and at three hierarchical levels of the lithosphere of the region. A modified method for determining the fractal dimension is applied, when the scaling data are approximated uniformly for territories of various shapes and sizes, subject to the maximum coefficient of pair linear correlation of the function lnN = f(lnr). Numerical implementations of epicentral field models in the form of a “Koch snowflake” and “Sierpinski carpet” confirmed the advantage of the method in conditions of limited data arrays used.Results. Seismicity reflects the process of fault formation in the lithosphere, and the use of the modified method allows one to obtain more accurate parameters of the state of the fault structure of the lithosphere from the field of epicenters of earthquakes in the Baikal region. The main influence on the assessment of the indicator is provided by two interrelated factors: the growth of instrumental data over time and the geometry of the distribution of earthquake epicenters over the territory. Using the maximum correlation coefficient to estimate the self-similarity of the field of epicenters of earthquakes in the Baikal region allows us to significantly refine the magnitude of the self-similarity index - the difference between the self-similarity index (D0 ≈ 1.70) and the cell dimension (D0 ≈ 1.58) significantly exceeds three standard deviations.Findings. The applied method has a particular advantage with a small amount of initial data and can significantly improve the assessment of the self-similarity index in conditions of a limited duration of instrumental monitoring of earthquakes. In the absence of reliable data on the deep structure of the fault-block geomedium, the approach used and the results obtained contribute to the understanding of modern geodynamics and seismotectonics of the lithosphere of the Baikal region by analyzing the fault structure of the territories through the fractal dimension of the earthquake epicenter fields. In practical terms, information on monitoring the state of the fault structure of the lithosphere according to earthquake data can be used to characterize the seismic situation and the danger in industrial and civil construction areas.

Based on the results of a laboratory simulation of the seismic fault reactivation by “stick-slip” process, it was shown that the system of two blocks just before an impulse offset goes through the meta-instable dynamic state, with early and late stages of meta-instability [Ma et al., 2012]. In the first stage the offset begins in slow stationary mode with slow stresses relaxation on contact between blocks. In the second stage of the “accelerated synergies” strain rate increases and, subsequently, the deformation process through a process of self-organization came to dynamic impulse offset. The experimental results were used for interpretation of the results of spectral analysis of the deformation monitoring data. The data were held within the southern part ofLakeBaikal, where Kultuk earthquake (27.08.2008, Ms=6.1). took place. Its epicenter was located in the South end zone of the main Sayan fault. Monitoring of deformations of rocks was carried out from April to November2008 in tunnel, located at30 km from the epicenter of the earthquake. The time series data was divided into month periods and then the periods were processed by the method of spectral analysis. The results showed that before the earthquake has ordered view spectrogram, whereas in other time intervals, both before and after the earthquake such orderliness in spectrograms is missing. An ordered view spectrograms for deformation monitoring data can be interpreted as a consequence of the self-organiza­tion of deformation process in the transition of seismically active fault into meta-unstable before the Kultuk earthquake.