Seismic process on the Krillon Peninsula (Sakhalin Island) after the earthquake on April 23, 2017

Research subject and methods. The seismicity of the Krilyon Peninsula (Sakhalin Island) after the earthquake on April 23, 2017 (M = 5.0) during the 2018–2021 period was investigated by the method of self-developing processes (SDP).Results. The seismic activity showed a damping trend after the earthquake (and several following aftershocks), with the activation of SDP seismicity observed in two cases. In the study area (40 km within the radius from the epicenter of the Krillon earthquake) and its immediate vicinity (up to 80 km), earthquakes with M = 3.9 and M = 4.3 were observed 74 and 26 days after seismic activations. These earthquakes are considered to be the strongest events occurred in the study area in the period under consideration. The results of the study were compared with the monitoring data of the Kamchatka branch of the Geophysical Survey Russian Academy of Sciences (KB GS RAS) on the volumetric activity of subsoil radon (OA Rn). It was revealed that the OA Rn anomalies detected in November 2018 and January 2020 had appeared several weeks after the identifed SDP. The anomalies were registered at observation points remote from the study area (as well as from the above-mentioned earthquakes) by no more than 50 km. Earthquakes in 2018 (M = 3.9) and 2020 (M = 4.3) occurred 19 and 32 days after the appearance of OA Rn anomalies. In general, the current situation can be assessed as calm, since, according to the analysis data, the seismic activity has no prerequisites for the transition from the decaying stage to the stage of stabilization. As shown in the work, this is a sign for preparing an earthquake with a magnitude higher than 5. Nevertheless, activation and (as a result) earthquakes of moderate strength (M < 5) are possible on a damping trend. Conclusion. It is proposed to take into account the self-developing processes of activation as a primary sign for a change in the geodynamic state of the environment, under which the appearance of OA Rn anomalies is possible. These anomalies are associated with the forecast of moderate seismicity during foreshock or aftershock activations.

The influence of geomagnetic and seismic parameters on mortality from cardiovascular pathologies in the Shamakhi Region of the Republic of Azerbaijan

Aim. Study of the dependence of mortality from CVD on helio-seismic indicators in the Shamakhi region of the Republic of Azerbaijan.Materials and methods. 352 case histories of patients who died in 2013 from various diseases were reviewed. The relationship was established between the number of deaths, their causes, distribution by sex and age with the magnitude of earthquakes, the depth of the epicenter and seismological activity by months. The data obtained were statistically processed using the Statistica 12.0 for Windows software package (Statsoft Inc., USA). To establish correlations, Pearson Chi-Square Tests was calculated, the results were considered reliable at p <0.05.Results. Statistically significant (p <0.001) more deaths were observed at the age of 80-89 years in men, and at the age of 70-79 years in women. Also, the relationship between mortality and the depth of the seismic process and the magnitude of the earthquake was established, in particular, the greatest number of deaths was observed at a depth of the seismic process <10 km and with a magnitude of 1.1-2.0 ml. In all months, the number of deaths was higher with a magnitude of 1.1-2.0 Ml. Statistically significant (p <0.005) was the fact that the nosology of the studied diseases was dependent on the age of the patients. Thus, a greater number of deaths in all age groups accounted for heart failure. A statistically significant (p <0.005) dependence of the depth of the seismic process on the month of death of patients was established, in particular, for all months, deaths coincided with the depth of the process less than 10 km. At the age of 40-70 years, a significantly greater number of deaths were from heart failure in men, and from 70 years and above in women.Conclusion. Thus, there is a close correlation between geomagnetic changes and mortality from CVD, which is realized in the form of an increase in the frequency of cases and deaths, and the number of these cases increases with the age of patients and changes in the magnitude and depth of the earthquake.

Recording and on-line analysis of the earthquakes at the National center of seismological data

The research is dedicated to statistical analysis of such a powerful natural phenomenon as an earthquake and to the problems of monitoring the seismicity in the territory of Ukraine directly. According to evidences of century-old data, annual number and the strengths of earthquakes differ, however its growth is observed definitively. Such a trend needs more attentive attitude to manifestations of seismic activity and its results even within the platform parts of the territory of Ukraine. Examples of registering earthquakes observations of different intensity and remoteness by Ukrainian observation net have been made. Special consideration at the National center of seismological data has been given to seismic vibrations which appear and are fixed in the areas bordering Ukraine and within its territories directly. Essential background for elaboration and successful practical usage of the medium-term and short-term methods of forecasting the approaching seismic catastrophe or dangerous development of the seismic process which has begun are observation and on-line processing of the earthquakes at the National center of seismological data with successive producing bulletins and catalogues.

The structure of deformation autosoliton fronts in rocks and geomedia

The paper describes numerical modeling of the generation and propagation of the fronts of moving deformation autosolitons in a loaded nonlinear strong medium. It presents solving a system of dynamic equations for solid mechanics, using an equation of state written in a relaxation form that takes into account both an overload of the solid medium and subsequent stress relaxation. The structure of a deformation autosoliton front is investigated in detail. It is shown that the front of a deformation autosoliton that is moving in an elastoplastic medium is a shear band (i.e. a narrow zone of intense shearing strain), which is oriented in the direction of maximum shear stress. Consecutive formation of such shear bands can be viewed as deformation autosoliton perturbations propagating along the axis of loading (compression or extension). A fine structure of a deformation autosoliton front is revealed. It is shown that slow autosoliton dynamics is an integral component of any deformation process, including the seismic process, in any solid medium. In contrast to fast autosoliton dynamics (when the velocities of stress waves are equal to the speed of sound), slow deformation autosoliton perturbations propagate at velocities 5–7 orders of magnitude lower than the velocities of sound. Considering the geomedium, it should be noted that slow dynamics plays a significant role in creating deformation patterns of the crust elements.