The paper describes experience of Geophysical Service (GS) RAS gained from use of CTBTO data and its data products as well as of KNDC data and data products in seismic monitoring in Russia and in bordering areas in near-real time mode data processing in 2016–2017. It is demonstrated the usage of waveforms, arrivals and Bulletin SEL1 data when in location by EEAS events on Russian territory.

At least thirteen small seismic events that occurred close to and following the North Korean underground nuclear test (UNT) on 3 September 2017 were detected and located by using seismic waveform data from regional stations. Other than the first event, widely reported to be a cavity collapse, the magnitudes of these shocks range from 2.3 to 3.6. Based on their timing, and proximity to the UNTs, these shocks may be considered as aftershocks. They are located within 1 km of each other with small relative location errors, approximately 50 m. We assess a method to classify each of these small events separately based on their spectral amplitude ratios derived from regional P- and S-waves. We examine additional possible small seismic events around the North Korean test site by using seismic data from stations in South Korea, Russia, and northeastern China including IMS seismic arrays, GSN stations, and national network stations. A linear discriminant function based on Mahalanobis methods applied to P/S spectral ratios does a better job of screening events than does a simple average of such ratios.

The magnitude and spectral discriminants of the PNS 09.09.2016 and 03.09.2017 are described in comparison with the records of the events following the most strong test on September 3, 2017, the collapse phenomenon, 8 minutes after the test, and two earthquakes, probably of induced character, on 23.09. 2017 and 12.10.2017, which occurred near the Pungery test site. The strongest test in North Korea made it possible to study the features of the wave pattern at teleseismic distances (Δ≥30ᵒ).

Susbsystem “Ozherelye” of peripheral points Zerenda, Vostochniy, Chkalovo of the large-base seismic array of Geophysical Observatory “Borovoye” has been studied. At the example of recording of underground nuclear explosions carried out at Nevada Test Site, local travel time curves and linear trends of the P wave travel time at the traces: “Pahute test site – peripheral points Zerenda, Vostochniy, Chkalovo” have been investigated.

A local travel time curve and a linear trend of the PKIKP_DF wave travel time at the Novolazarevskaya seismic station in Antarctica from underground nuclear tests at the Semipalatinsk Test Site (STS) in Kazakhstan between 1964 and 1989 was considered.

The response of the seismic background to pulsed geomagnetic variations is investigated for the conditions of the midlatitude Geophysical observatory “Mikhnevo” of the Institute of Geosphere Dynamics of the Russian Academy of Sciences. During the impulse variations of the magnetic field of SSC- and SI-types, in most cases, increased variations of the seismic background are observed in the frequency range of 0.01–0.1 Hz (in some cases, 0.001–0.1 Hz). The application of methods of statistical data processing made it possible to establish that it is the perturbation of the geomagnetic field that entails a change in the microseismic background and with some delay. The significant correlation between the amplitude of the geomagnetic impulse and the amplitude of the induced variations of the seismic background was established and the quantitative relationship between them was obtained. The analysis showed that after the geomagnetic impulse with a short delay in the behavior of the magnetic tipper module, “jumplike” changes (i.e., a change in the magnitude of the induced electric currents) are observed.

The problem of studying the interaction of various geophysical (seismic, acoustic, meteorological) fields is considered in the context of prediction of geo-ecological risks generated by technogenic and natural phenomena. In this connection the vibration method of studying the geophysical fields offered by the authors is considered and investigated. Thanks to high metrological and ecological characteristics of seismic vibrators high accuracy and repetition of the research results in the considered sphere are achieved as well as the ecological compatibility of their acquisition. The results of the research have been substantiated both theoretically and experimentally.

In connection with introduction of network technologies of data acquisition in systems of active geophysical monitoring of environment medium methods and algorithms of the operative analysis of data in rate of their receipt is actual. As an example algorithms serial cross-correlation convolution of data in systems of active monitoring of environment with application of the seismic and acoustic oscillations generated by seismic vibrators are considered. The vibrators find more and more wide application in deep seismic sounding of the Earth, acoustic monitoring of atmosphere, etc.

This report presents the results of a detailed analysis of the variations in geomagnetic parameters on the eve and during the strong earthquake of November 25, 2016 (M=6.4) that occurred in the border area of Tajikistan, China and Kyrgyzstan. To assess the state of the geomagnetic field, the data of the geomagnetic observatory “Alma-Ata”, the international code – AAA; geographical coordinates [43.25°N; 76.95°E]; geomagnetic coordinates [34.3°N, 152.7°E]. A detailed analysis of the variations of the seconds values of the X-, Y-, Z-components of the geomagnetic field showed that sinusoidal oscillations with periods of the order of 52–55 minutes appear before the earthquake in variations of the geomagnetic field.

The reference-information system that includes all results of the years-long activities (1965…1988) on peaceful nuclear explosions (PNE) in the USSR is presented. A user of this reference-information system can obtain maps of PNE sites and regions, as well as photographic, video, technological documents and facilities with violations of experiment conditions. This information system can immediately provide reference data on explosions (coordinates and well geometry of an explosion, its nearby territory and purpose, its results and characteristics, radiation situation just after a particular explosion, facility’s condition at the modern stage, etc.). This reference-information system can be of great help to researchers as well as local administration bodies involved in activities of ecological safety and population awareness-building.

The paper considers the problem of velocity model reconstruction of an elastic medium in the problem of monitoring the zones of underground nuclear explosions. An approach based on solving a set of forward geophysical problems is considered. For the first method, a brief description of the method for numerical simulation of the full wave field is represented. Results of numerical experiments on modeling the medium with inclusion are also presented. Inclusion is an analogue of the cavern formed as a result of underground nuclear explosion. The software for creating 2D and 3D models of heterogeneous elastic media was developed. Theoretical results of experiments are presented.

Lithosphere-atmospheric-ionospheric relations have been investigated at the example of the perturbations propagation from the lithosphere to ionosphere during underground nuclear explosions at the Semipalatinsk test site and two earthquakes (Mb = 3.5 and Mb = 3.6) near Almaty. Simultaneously, seven days prior to the earthquake the abnormal effects in variations of intensity of a gamma-ray flux, temperatures, acoustic impulses and the Doppler frequency shift of ionospheric signal are registered by a complex of the measuring equipment installed in the mountain area. A retrospective analysis of the recordings of the Doppler frequency shift of ionospheric signal variations during the UNEs at the Semipalatinsk test site detected disturbances in the DFS records 15–18 minutes after the explosion and the response of ionosphere to the acoustic wave. The anomalous effects recorded in ionosphere when UNE radioactive products penetrated the atmosphere and when gamma-ray flux increased prior to earthquake, apparently have a common mechanism for disturbances perturbation to ionosphere, namely, the ionization change of the atmospheric boundary layer leading to the total current change between the ionosphere and the Earth.

The paper proposes a scientific-methodological approach to determine the negative consequences of high-intensity impacts of large-scale explosions on the rock mass at the example of “Zarechye” site of the Semipalatinsk test site. The results of observations for the period of 1987–1990 over the underground water level in wells with depths from 75 to 200 m were used as the raw data. A comparative analysis of level alterations along a profile of reference wells is aimed to identify the areas of time-spatial redistribution of the underground flow. The change of hydrogeological condition is considered as an indicator of the changing deformation regime of the rock mass subjected to a high-intensity impact.

Efficiency of seismological monitoring by the Voronezh stations network (VMGSR) that records seismic events starting from the 2nd energy class has been demonstrated at the example of Kursk and Novovoronezh NPP location regions. The results of seismological monitoring allow to optimally and scientifically estimate seismic and seismic-tectonic conditions and their stability in nuclear station locations regions.

The paper presents the results of detection and tracing of structural and material changes in the soil of some nuclear energy facilities placements of Kazakhstan based on geophysical and athmogeochemical data. Spatial and temporal connection of changes of electrical resistivity, natural seismic noise, gas permeability of the sand-clay section rocks, connected with deformation processes has been demonstrated. The results of the testing of potential geophysical technologies and observational networks of monitoring at the test facilities are presented.

It was demonstrated that within the eastern part of Northern Tien-Shan and Dzhungarya active faults with wings shifted in the late Pleistocene – Holocene have the striking different from the direction of the newest structures, mainly sublateral ones. These faults represent right-shift disjunctive structures of north-western strike. They are the responsible ones for modern seismic situation at the investigated territory.

In this paper, seismic monitoring systems in Central Asia are presented. The description, some characteristics and history of creation of the stations entering into national seismic networks of monitoring are given. A review is provided for stationary and temporary systems for recording earthquakes and nuclear explosions for the period of up to 2018 and their use when solving various tasks in research projects.

The seismicity of the region of Kapshagai hydro-electrical station dam’s location has been analyzed. Objects of maninduced impact of continuous nature located under the zone of direct impact from the vibrations of turbine motors of hydro-electrical station and pit explosions. Based on a number of earthquakes before and after the filling up of the water reservoir in 1970 as well as on the increase of the share of medium earthquakes in 2011–2018, a conclusion is made on the increasing man-induced seismicity. The attention is drawn to the location of the water reservoir directly on the Altyn-Emelskiy fault and the possibility of this fault’s activation during further hard man-induced impact.

The analysis results of power class value distributions of technogenic seismic events in the territory of the Voronezh crystalline massif are given in work. It is established that for the same events the value of a power class varies depending on distance and can differ in hundreds of times. The major influencing factor is generally amplitudes of transverse waves.

The paper presents the results of a long-term seismological monitoring within the Starobin potassium salt deposit of Belarus carried out since 1983 till 2017. The seismicity not directly caused by specific deposit mining conditions, but due to the underground rock excavations is discussed. The fact of the induced seismicity manifestation is caused by the fault activation in the salt mining region as a result of changing the stress conditions in the horizons subject to the action of the natural tectonic forces. Spatially, the seismicity manifestations are observed beyond the mine field limits and involve the territories adjacent to the mining region. The averaged values of the seismicity increase are weakly dependent on the mining excavation features, but, firstly, on the geometry of the faults found in the region and the pattern of the regional tectonic stresses.

The information about the perceptible earthquake with MPVA=6.2 occurred on the southern shore of Issyk-Kul Lake on the southwestern slope of the Tegerek Mountains (Kyrgyzstan) on November 14, 2014 is presented here. Basic parameters of the earthquake focal mechanism have been estimated and the distribution of aftershocks has been obtained. The results of the macroseismic survey are presented. The position of the source on tectonic fault circuit of area and in the context of the historical seismicity are presented.

Infrasound is one of the technologies of the International Monitoring System (IMS) supporting the verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In the frequency band of interest to detect atmospheric explosions, ambient noise may affect detection and particularly ocean noise referred to as microbaroms. Ocean wave interactions generate acoustic noise almost continuously which can obscure signals of interest in their frequency range. The detectability of such noise strongly depends on atmospheric conditions along the propagation paths. Using ocean wave action model developed by IFREMER and considering the effects of general middle-atmospheric products delivered by ECMWF in long-range propagation, microbarom amplitudes and direction of arrivals derived from various propagation models are compared with the observations. With this study, it is expected to enhance the characterization of the ocean-atmosphere coupling. In return, a better knowledge of microbarom sources would allow to better characterize explosive atmospheric events hidden in the ambient noise.

The Kazakh monitoring network consists of four seismic and three infrasound arrays. All the arrays record low frequency signals mostly from North-West. A dominating source region of microbarom/microseism signals is located in North Atlantic [1]. Time dependent simulations of the microbarom/microseism source regions are made using a hydrodynamic model of ocean wave interactions developed by IFREMER. Comparisons between observations at the Kazakh monitoring network and modelling results are carried out.

Three-component seismic station Ala-Archa was certified in 2017 as an auxiliary seismic station AS060 of International Monitoring System created by the Comprehensive Nuclear Test Ban Treaty Organization. Based on the records of this station a comparative analysis of waveform of underground nuclear explosions carried out at regional distance has been implemented: at Lop Nor site in 1983–1996, at Semipalatinsk Test Site in 1983–1989, at Pokharan and Chagay test sites in 1998. Spectral ratios of main seismic regional phases of underground nuclear explosions and earthquakes were studied.

The physical processes of the origin of the earthquake were considered. The main aspects of earthquake occurrence were formulated. These include: energy sources, factors of perturbation of dynamic processes; dynamic processes of the Earth that take into account complex processes of the Earth's motion (rotation, motion along the orbit, etc.). Some issues of earthquake prediction are outlined, as well as a procedure for diagnosing the state of the environment.

Description of Sarezskoye earthquake of December 7, 2015, features of its manifestation on the surface, confinement to the geological structures and isoseist maps have been presented. A comparative analysis with the earthquake of February 18, 1911, have been presented and there is a conclusion on a possible deep earthquake in the vicinity of Sarez lake according to 2015 scenario.