EARTHQUAKE OF SEPTEMBER 16, 2020 IN KIROV-KAZHIM AULAKOGEN
N.N. Noskova
Institute of Geology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia
E-mail: nataliyageo@mail.ru
Abstract. On September 16, 2020, an earthquake was registered in the Slobodsky district of the Kirov region. The instrumental data processing was carried out on the basis of seismograms of 11 stations with epicentral distances from 69 to 660 km and an azimuthal environment of 1.4–322.8 °, GAP = 124°. It is classified by us as tectonic and has the following parameters: coordinates 58.755N, 50.588E, time at the source t0=01:04:44 (UTC), depth h=6 km, energy class according to T.G. Rautian Kp=9.4, ML=3.2, MS = 2.4, error ellipse AzMajor=20 °, Rminor=4.5 km, Rmajor=7.3 km. The event was not felt by residents of nearby localities, probably due to the fact that the seismic event was of low magnitude and occurred at night. In tectonic terms, the September 16 earthquake belongs to the Kirov-Kazhim aulacogen of the Volga-Ural anteclise of the Russian plate of the East European platform (EEP). Historical earthquakes are known near the epicentral area of the September 16 event, as well as instrumental ones with ML=2.6–3.4. The 5-point Verkhoshizhem earthquake of 2000 and two 7-point earthquakes: Sysolа 1939 and Vyatkа 1897 with macroseismic manifestations are especially noticeable in the study area. Earthquakes mainly occur on the sides of the aulacogen and are probably confined to the northeastern-striking faults that control the most submerged central graben of the aulacogen. The occurrence of seismic events on the EEP indicates that it is a fairly mobile structure, especially in its marginal parts.
Keywords: earthquake, epicenter, weak seismicity, Kirov-Kazhim aulacogen, East European platform
About the author
NOSKOVA Nataliya Nikolaevna –Institute of Geology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences. Russia, 167982, Syktyvkar, Pervomayskaya st. 54. E-mail: nataliyageo@mail.ru
Cite this article as: Noskova N.N. Earthquake of September 16, 2020 in Kirov-Kazhim aulakogen, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology). 2020. V. 47, No. 4. P. 92–100. [in Russian]. https://doi.org/10.21455/VIS2020.4-6
English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990