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For the first time, a numerical comparison of the General Seismic Zoning (GSZ) maps with the effect of earthquakes that actually occurred after the publication of the maps was carried out. The area of zones of expected intensity on the GSZ map is compared with the area of isoseists from actual earthquakes. It turned out that the isoseist area is on average by an order less than expected according to the GSZ. This paper describes possible reasons for such an overestimation and proposes ways to improve seismic hazard assessments. [ABSTRACT FROM AUTHOR]

The paper presents the results of modeling the stress–strain state of the epicentral zone of the strong crustal Hanshin–Awaji earthquake, which occurred in the area of Kobe (Japan) on January 17, 1995, with a magnitude M of 6.9. In this work the author's method for modelling and analyzing the stress–strain state of the epicentral zones of crustal earthquakes was used. The geological, tectonic, and seismological data for the earthquake region are used as input data and boundary conditions for modeling. In this work it is shown that the main rupture arising at the origin of the earthquake is generated in a zone of high stress intensity at a certain ratio of the main tectonic stresses and propagates through areas of anomalously high stress concentration, causing maximum displacements in these zones. The results provide new insights into the focal mechanism of an earthquake, aimed at predicting the location and magnitude of strong crustal earthquakes in earthquake-prone areas. [ABSTRACT FROM AUTHOR]

Studies have been conducted on the variations of microseismic noise recorded by broadband and short-period seismic stations in the area of South Baikal before and after the large December 9, 2020 Kudara earthquake with Mw = 5.6. Ten days before the earthquake, there was a gradual increase of oscillation amplitudes in the frequency range from 0.01 to 0.1 Hz, with an increasing background observed also during 4 days after the main shock (period from December 1, 2020 to January 12, 2021). The maximum amplitude increase is 19.5 against the background. During this time, there were recorded 48 aftershocks. The analysis of direction of particle motion in seismic waves over the reporting period showed an abrupt change in the orientation of oscillations, which is fully consistent with the azimuth for the main shock epicenter. The analysis of seismograms over the next period (from December 13) did not show similar effects in the microseismic noise field. Apparently, the microseismic noise field reflected the process of slow faulting before the earthquake and after the main shock with subsequent attenuation. [ABSTRACT FROM AUTHOR]

The results of study of the emanation response to large seismic events within the Baikal region for a year are study. In the course of this study, monitoring of the radioactivity of underground waters in the Southern Baikal region was organized and a set of the most significant earthquakes was identified. The radii of the influence zones of these seismic events were calculated, and these zones were grouped in accordance with their spatial position relative to the sampling station. Three types of emanation responses to seismic events have been identified, one of which reflects the emanation field response not to the event itself, but to the process of its preparation; i.e., it is a precursor effect. The grouping of seismic events in terms of their distance from the sampling station virtually coincides with how the events are grouped based on the type of emanation response. The results obtained show that the identification of short-term emanation precursors of strong earthquakes within the Baikal region is possible if a seismic event is strong enough and if a monitoring station is located within the zone of influence of the event. [ABSTRACT FROM AUTHOR]