Seismic and geodetic observations preceding major earthquakes are important sources of information about the deformation processes occurring in the vicinity of the future earthquake hypocenter. The article presents the results of estimates of the possible contribution of static and dynamic deformations induced by large foreshocks to the initiation of the Kamchatka great earthquake on 07/29/2025, M_w 8.8. The results of calculating the values of variations in the Coulomb stress field on the plane corresponding to the mechanism of the main shock and main foreshocks, as well as shear dynamic stresses and deformations in seismic waves emitted during movements in the foci of the considered sequence of events, are presented. The estimates showed that the values of dynamic stresses and deformations affecting the hypocenter zones of the main foreshocks and the main shock from earlier events could reach values σ_d ~ 3 MPa, deformation ε ~ 10^-4; variations in Coulomb stresses reached several bars. The calculation results indicate that the likely trigger of the Kamchatka great event was a sequence of earthquakes that occurred over the past 10 days in the vicinity of ~ 50 km from the hypocenter of the main shock.

The formation of gas filtration pathways on the seafloor resulting from gas hydrate decomposition is studied. It is shown that the plowing furrow formed by a stamukhi thrusting onto the seafloor disturbs the stress state of the bottom layers. It is established that the formation of gas migration pathways can be explained by the disturbance of the stress state of the bottom layers during furrow formation. A geomechanical model is developed for the formation of gas filtration pathways resulting from gas hydrate decomposition in an elastic-plastic medium with gas hydrate inclusions randomly distributed. The law of non-associated plastic flow with the Drucker–Prager limit condition and softening is used to describe the failure of the medium. Softening leads to the development of instability and localization of shear deformation in narrow zones. This results in localized cracking of the strata, which creates pathways for gas escape.

Computer modeling is used to examine the formation and rise of a gas and dust cloud after one-ton TNT explosions in boreholes located at the center and vertices of a regular hexagon. The size distribution of ejected soil particles is described by the Rozin–Rammler formula. This formula includes two unknown parameters, determined experimentally and characterizing the specific features of rocks in which the explosions are performed. The study examines the influence of these parameters on the rise of the gas-dust
cloud and the mass of dust contained within it.

This study presents the results of experimental modeling of free gas bubble transport in a water-saturated sandy porous medium. The main focus is on the development and validation of an original laboratory technique based on an optically transparent flat micromodel that enables visualization of gas saturation distribution through digital image processing. It is shown that when a gas bubble passes through the saturated sand sample, a conductive channel is formed, accompanied by a sharp increase in fluid flow, while residual gas saturation remains within the pore space. In single-bubble experiments, the residual gas saturation was independent of the bubble volume, whereas in sequential injections of multiple bubbles it stabilized at about 0.25. No  significant deviations from linear filtration roperties were observed. The obtained results are of  methodological significance and can be used to refine the parameters of two-phase flow models applied to numerical simulations of gas transport in Arctic shelf sediments.

This article presents the results of experiments conducted on a two-dimensional optically transparent model, aimed at physically modeling a gas outburst in a loosely cohesive granular medium. The proposed model allows for visualization of the processes of gas destruction in the medium during gas filtration, followed by the release of the destroyed mass. Images of the formation of domes above the daylight surface 
and their destruction are obtained in real time. After the outburst, craters form, which retain their shape in the case of wet sand due to the strength generated by capillary forces. Based on the experimental results, the geometric parameters of the craters were determined depending on the depth of the gas source.

Calculations of a vortex structure formation in the vicinity of the focus of a perturbed converging shock wave were performed, based on the compressible Euler equations in the framework of 2D formulation. The low-mode perturbation leading to limited cumulation is considered. At the stage of the converging shock wave, the latter is a source of flow vorticity, the intensity of which increases with decreasing distance to the focus according to a power law. The formation of the most intense vortices is observed on the scale of the transition from the Mach to the proper (regular) interaction of segments of the converging shock wave. It is shown that the presence, along with the second mode, of intermediate unstable modes leads to the intensification of mixing of high-entropy gas in the vicinity of the shock wave focus. In the presence of only the second mode, the hot high-entropy gas is concentrated in the cores of two vortex pairs formed as a result of the interaction of two converging jets. For the first time, it is shown that a small perturbation by shear in the plane of symmetry on the generation scale leads to asymmetric flow swirl on the scale of the cessation of cumulation.

Numerical modeling is used to examine cylindrical explosions in the air, simulating the energy release in the atmosphere during the passage of meteoroids with radii of 1–10 meters. It is shown that the shock wave generated by such explosions becomes spherical at large distances, but its amplitude depends on the angle between its propagation direction and the meteoroid’s trajectory. The wave propagating perpendicular to the trajectory has the maximum amplitude. The dependence on the angle increases with decreasing meteoroid radius. Regions of space are determined in which the arrival of a weak cylindrical wave is first observed, followed by a stronger spherical wave, and regions of space in which only the arrival of a spherical wave is observed.

The hypothesis that the Moon formed from a near-Earth swarm, formed by the gravitational capture of bodies from the planet’s feeding zone during planetary accumulation period and replenished with material ejected by the impacts of large bodies, was proposed long ago. However, the substantiation of this hypothesis is far from complete, although it is highly relevant given the lack of a comprehensive theory of the Moon’s origin. In this work, a numerical simulation of the impacts of large bodies on the Earth at different velocities was carried out and the masses and velocities of material ejected into ballistic and
heliocentric orbits, as well as the concentration of iron in these ejections, were determined. The total mass of ejecta during the growth of Earth, starting from the moment when it accumulated half of its present mass, is more than ten lunar masses at impact velocities slightly exceeding escape velocity, and increases with increasing impact velocity. The probabilities of multiple passes of fragments ejected into heliocentric orbits through the Hill sphere, the complexities of the co-accretion multiple-impact model and the prospects for its development are considered.

A catalog of craters, which were recently formed by meteoroid impacts on the surface of Mars, provides an opportunity to study the meteoroid population, which is common to Earth and Mars. Crater size distributions were constructed for clusters from previously identified groups (a dominant main crater, densely populated clusters, and sparsely populated clusters with several largest craters of comparable size), and the average slope of the resulting approximations was estimated. Applying a standard power law resulted in mean exponents of 0.8, 2, and 1.5 for the considered groups of clusters. When using a truncated power law approximation, the average slopes vary within a narrower range (0.8–1.1). It is hypothesized that the identified groups may correspond to different types of impactors and/or different types of meteoroid breakup in the atmosphere.

This study analyzes the temporal dynamics of average monthly and average annual air temperature values based on instrumental observations of temperature variations at the Zugspitze high-altitude weather station from August, 1900 to July, 2025. Several methods were used to isolate the trend component and locate the change point of temperature variations: the Mann–Kendall test, the Theil–Sen estimator, the singular spectrum analysis method, the CUSUM algorithm, and the segmented regression analysis method. It was found that air temperature changes tend to increase over time. Identification of the trend component using the singular spectrum analysis method demonstrated an increase in the rate of temperature increase starting around 1969 is confirmed by the results obtained using the segmented regression analysis method and the CUSUM algorithm. The two-segment regression provides a good approximation of temperature variations over the period from 1901 to 2024 (the coefficient of determination is 0.61).

Atmospheric turbulence causes distortions in the wavefront of propagating optical radiation. This leads to a degradation of image resolution in astronomical telescopes and significantly reduces the power density of radiation on the target when focusing. The influence of turbulent fluctuations on the wavefront can be studied in laboratory conditions using a deformable mirror as a phase fluctuations generator and a wavefront sensor as a distortion measurer. We have developed a software simulator and an experimental setup for
generating atmospheric turbulence phase fluctuations, as well as an adaptive optical system to compensate for the induced aberrations. Both systems use 60-mm diameter bimorph deformable mirrors with 92 control channels and two tip-tilt correctors. The wavefront is measured using a high-speed Shack-Hartmann wavefront sensor based on an industrial CMOS camera. The system achieved a correction frequency of 600 Hz, reducing the aberration amplitude from 2.6 μm to 0.3 μm during the correction process. The
application of the tip-tilt corrector reduced the range of focal spot centroid jitter by a factor of 2–3.