To construct adequate computational models for the preparation of earthquakes, it is important to use correct estimates of the properties and dimensions of the fault damage zone, where the material has  increased fracturing and permeability, and reduced elastic wave propagation velocities. The article  presents the results of numerical modeling of the process of formation of a disturbed zone during  the dynamic propagation of an earthquake rupture. In this case, both shear and tensile failure of rocks were considered. It is shown that the overall pattern of rock destruction strongly depends on the depth of the rupture. With the parameters of the environment and the stress field used in the calculation, at a depth of more than ~ 9 km, lithostatic stresses completely block the destruction by tensile. At depths less than ~6 km, avulsion is the main mechanism of rock failure.

The article presents the results of calculations of the mechanical and seismic effects of underground nuclear explosions carried out at a depth of more than a kilometer. A comparison is made of the modeling results, carried out taking into account the action of lithostatic pressure, with the data of recording the parameters of seismic explosion waves during known experiments on the island Amchitka (USA) «Cannikin» (explosion depth H = 1791 m) and «Milrow» (H = 1219 m). In addition, calculations were made of the maximum values of the relative coefficient of change in the permeability of the rock mass in the near zone of the explosion. It is shown that the methods used in the numerical modeling of the mechanical and seismic action of an explosion satisfactorily describe the parameters of seismic waves and the configuration of the zone of material destroyed by the explosion. At the same time, the calculation results do not provide quantitative information about the degree of damage to the massif and changes in its integral properties. However, the use of previously established correlation dependencies makes it possible to evaluate such properties as post-explosion permeability, seismic waves propagation velocities, apertures of fractures opening, etc. The results of such estimates can be used as input data when modeling a number of physical problems.

The paper analyzes the variation in the parameters of the tidal lunar declination wave M_f in the variation of the Earth rotation angle (UT1–UTC time series). The source data was bulletin EOP14C04 of the International Earthʼs Rotation and Reference Systems (IERS), which contains data on the parameters of the Earth rotation (ER) from 1962 to the present in one-day increments. It is shown that all periodic components of the variation of the M_f parameters, where the main one is the orbital period of the lunar nodes with a period of 18.6 years, completely coincide with the corresponding parameters of the M_f wave for the deformation tide, isolated from the total tide obtained using the standard ETGTAB package. Shown, as an example, is the forecast for the development of the M_f wave of the Earth rotation until 2035.

The paper analyzes the variation in the amplitude and periods of the Chandler and annual components according to the International Earth Rotation and Reference Systems (IERS) bulletin EOP14C04, which contains data on the deviation of the North Pole from 1962 to the present with the sampling time of one day. A specially created digital symmetrical non-recursive filter was used to isolate the main harmonics of the pole motion. It is shown that these components manifest themselves as two connected oscillating systems that are in permanent exchange of mechanical energy, and the change in the energy of these oscillations has a mirror-symmetrical appearance. This exchange occurs from a state of complete dominance of the Chandler component to its almost complete attenuation. The latter circumstance allows us to estimate the relative masses of these oscillating systems, which shows the exceptional role of the Earth’s core in the formation of the Chandler component of the pole’s movement.

In the present work are investigated the features of rock fracture on the scales of 10^-6 – 10^-4 m in zones of intense tectonic deformations. A statistical analysis of the fragmentation of zircons selected from the central part of the Primorsky fault of the Baikal rift zone has been carried out. Photos of zircon in transmitted light and cathodoluminescence images were considered. The segmentation of zircon images was performed based on artificial intelligence algorithms and expert opinion. Three models power, exponential, and lognormal were selected to describe the statistical properties of zircon fracturing. The analysis, based on Kolmogorov – Smirnov statistics using the bootstrap technique, revealed that the lognormal model is the most effective in describing zircon fragmentation under long-term intense tectonic deformations.

We present our results on the numerical modelling for the SHF-UHF radiowave propagation in dusty environment. The problem is solved by means of the parabolic equation technique in paraxial mode within the effective dielectric permittivity framework. Air humidity and visible range are used as free model parameters. The results for the attenuation at 3 and 10 GHz are presented. These results prove that geophysical processes in the atmospheric boundary layer involving dust of various origin can significantly impact on the UHF-SHF electromagnetic wave propagation.

The data of instrumental observations of variations of the geomagnetic and electric fields in the surface atmosphere during the flight and explosive destruction of the fireball on April 30, 2024 on the western border of the Belgorod region are presented. Using data obtained at the observatories of the INTERMAGNET network and the Mikhnevo Geophysical Observatory of the IDG RAS, it was shown that the destruction of the bolide, which occurred in two stages, was accompanied by variations in the magnetic field at epicentral distances up to ~ 2000 km and variations in the electric field strength at a distance of ~ 500 km. Based on the results of processing ionograms of high-frequency ionospheric sounding obtained at the Space Research Center of the Polish Academy of Sciences (Warsaw), the ionospheric effect of the event in question was demonstrated in the form of variations of the critical frequency f₀F2 with an amplitude of ~ 0.4 MHz.