This study, conducted within the context of earthquake prediction, is devoted to the theoretical justification of an approach for determining focal parameters based on satellite monitoring of ground displacements in regions with increased seismicity. Based on 2D and 3D geomechanical models treating the Earth's crust as an elastic half-space and the concept of an earthquake focus as a point "double-force" source, inverse coefficient problems are formulated for finding the hypocenter coordinates and force components based on daylight surface strains calculated from satellite geodesy data. Numerical experiments using synthetic data establish the solvability of the inverse problems.

The paper demonstrates that the Omori and Gutenberg–Richter laws can be written in discrete form and do not require approximation by continuous processes. The variance of average distances from a crack to its nearest neighbor plays a key role in determining the hazard of catastrophes. Zero variance results in discrete-impact catastrophes. Increasing variance initially weakens catastrophes until they disappear. Then, with further increases in variance, catastrophes of a completely different nature arise, which can be interpreted as the failure of a body without a prior history of this failure, i. e., as the sudden disintegration of a body with an internal structure. This phenomenon may be related to the occurrence of earthquake swarms.

The spatiotemporal distribution of aftershock sequences nine of the strongest (7.5 ≤ M_w ≤ 7.9) crustal intraplate earthquakes in Central Asia (φ = 20–50° N, λ = 57–120° E) was analyzed for the observation period of 1976–2016. The dynamics of the seismic process development was assessed based on the values of the total scalar seismic moments released during daily, 10-day, monthly, and annual periods during the development of aftershock series with m_b(ISC) ≥ 4.5. As a result of the analysis of fragments of aftershock series along the linear extent of the rupture of the main foci, the largest bursts of activity were noted near the epicenter of the main event or at the end of the aftershock region.

This study examines the features of the seismic regime of the Tuva-Mongolian block, located at the junction of the Altai-Sayan mountain region and the Baikal Rift Zone. The distribution of earthquake hypocenters within the block and adjacent territories (East Tuva Upland, Hangai Massif) is analyzed. Differences in seismicity types of neighboring structures and the influence of plume processes on the modern seismic activity of the region are discussed.

New data on the formation of an earthquake preparation zone, based on the development of S.V. Goldin's concepts, are presented. Evidence is obtained of the repacking of the block system on the eve of a strong earthquake, the formation of a deformation shadow zone in the area of the future earthquake, and the nature of medium-term seismic quiescences and short-term silence pauses is discussed.

A retrospective description of the evolution of the methodological approach to the localization of crustal earthquakes (conventionally called "refined hypocentry") is given using the example of data obtained in the Central Baikal region. Both archival records of past earthquakes (for the period 2001–2003) and relatively modern data (2020–2021) were used. A number of well-founded methodological solutions are proposed to improve the accuracy and reliability of localization with examples of their application on real data.

This paper examines the full-waveform inversion method in the image domain. A theoretical and numerical analysis of solutions of the inverse dynamic seismic problem in the image domain is performed using asymptotic methods. A Gaussian beam migration operator is used for transformation to the image domain. A theoretical and numerical comparison of reflection tomography and the developed asymptotic full-wave inversion method is presented. A connection is established between the operators of linearized problems of tomography on reflected waves and asymptotic full-waveform inversion in the image domain. Numerical experiments have shown that reflection tomography is effective for reconstructing low-frequency models, while asymptotic full-waveform inversion in the image domain ensures the restoration of details of complex medium structures, with computation speeds being approximately equal for both methods.

The article presents the results of processing detailed CDP-data using the dynamic conversion method. An algorithm for separating coherent refracted waves of the first and subsequent arrivals has been developed, based on the F–K filtering of seismograms. It was determined that the shape of the spectra of refracted P- and S-waves is bell-shaped, with a pronounced predominant frequency (varying in the ranges of 15–27 and 12–17 Hz), the spectra of the original recordings are low-quality, without obvious maxima. Information on the dynamics of refracted waves formed in the upper crust of folded systems was obtained in the 1-SB profile: blocks ranging from 5 to 60–300 km in length, separated by zones with a reduced amplitude of coherent waves and sizes up to 10 km, were identified based on sharply changing frequency spectra, amplitude, and attenuation coefficient.

A comparative dispersion analysis using the passive MASW method was conducted for data from distributed acoustic sensors (DAS) and three-component geophones during surface wave recording with a controlled noise source (vehicle). The impact of DAS parameters and array length on the frequency content was revealed. DAS spectral images show systematically overestimated phase velocities compared to geophones while preserving the fundamental mode structure, confirming applicability for monitoring near-surface velocity changes.

In this paper the algorithm for borehole vicinity imaging from vertical seismic profiling data with controlled reflection angle, developed previously in IPGG SB RAS, is implemented and investigated in case of anisotropic medium within its vertical symmetry plane. Realization of ray tracing with reflection and refraction in anisotropic medium is considered along with application of parameter providing solution stability. Resolving the rays of reflected and refracted waves requires solving the fourth order algebraic equation. General case of anisotropic medium requires developing a more complex algorithm.