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Abstract—The paper presents the results of many years of research on the compilation of a consolidated, refined, unified earthquake catalog for the western sector of the Russian Arctic for the entire instrumental observation period, in particular for the period from 1908 to 2020. The catalog includes data on recent seismicity in areas previously unavailable for detailed seismic monitoring. Based on the results of the study, we were able to more accurately determine the spatial distribution of seismicity in the region and compare the instrumental data with parameters of lineament-domain-focal (LDF) models of the General Seismic Zoning maps (GSZ, from Russian term abbreviated as OSR)—OSR-97 and OSR-2016. In the western sector of the Russian Arctic, the highest seismicity is observed in the continent-ocean transition zone, in the Belyi (Kvitøya) Island, Novaya Zemlya and Severnaya Zemlya archipelagos. The very shelf of the Barents and Kara Seas is characterized by rare and scattered seismicity. The configuration, the maximum possible magnitudes, and the depths of the seismogenic layers in the LDF models of OSR-97 and OSR-2016 maps are not always consistent with the instrumental data and need a correction. The consolidated refined earthquake catalog can be used as a basis for the further research aimed at seismic hazard assessment of the territory, construction of geodynamic models, and study of the stress-strain state of the Earth's crust. [ABSTRACT FROM AUTHOR]

The East European Platform (EEP) is characterized by a rather weak seismicity. The south of the Komi Republic is the most seismically active territory in the northeast of the EEP. The 1939 Sysola earthquake (grade 7), one of the strongest earthquakes in the European north of the 20th century, occurred there. Many world's seismic stations recorded an earthquake in the Priluzsky region of the republic on 9 November 2002, but it was not thoroughly studied and is not considered in literature. In this work we recalculate the parameters of the earthquake hypocenter, substantiate its tectonic nature, construct its focal mechanism, and describe its tectonic position. For processing, we used data on 86 seismic phases from 58 stations with epicentral distances from 5.9 to 57°, azimuth angles from 1.5 to 341.7°, and the maximum azimuthal gap of 70°. The following parameters of the hypocenter were obtained: t0 = 06 h 47 min 17.9 s, 59.93° N, 49.76° E, Rminor = 7.7 km, Rmajor = 10.7 km, Azmajor = 20°, h = 16 km, and Ms = 3.4/5. The earthquake is localized in the upper crust and is confined to the zone of the junction of the eastern slope of the Sysola arch and the western flank of the Kirov-Kazhim aulacogen of the Volga-Ural anteclise of the Russian Plate. We have established a strike-slip fault focal mechanism of the earthquake, which corresponds to the latest stress field of the region. The estimated axis parameters (value, azimuth, plunge) are as follows: T = 0.707, 90.0, 0; N = 0, 0, 39.792; and P = -0.707, 180.0, 50.208. The plane parameters (strike, dip, slip) are estimated at 327, 57, -140° for the first plane and 213, 57, -40° for the second plane. The recorded seismic events in the northeast of the Russian Plate indicate that the platform area is not seismically passive. The performed research shows that recent seismotectonic processes are related to the structure and state of the Earth's crust within the platform. [ABSTRACT FROM AUTHOR]