Earthquake on December 26, 2023 in the Kirov-Kazhim aulacogen

The accident was registered in the Zuevka District of the Kirov Region in the upper reaches of the Cheptsa River on December 26, 2023. The purpose of this work is to analyze seismic data obtained by regional seismic stations, calculate the main parameters of the seismic event happened on December 26, 2023, and determine the seismotectonic position of the epicentre. The seismic event was recorded by seismic stations of the Komi Republic, Bashkortostan, the Perm Territory, Arkhangelsk, Kirov, Orenburg, Samara, Saratov, and Sverdlovsk Regions. The event was analyzed using wave forms of 24 stations with epicentral distances from 81 to 1352 km, azimuthal environment - 18-359.5°, GAP=80°. The instrumental processing gave the following parameters of the December 26 earthquake: coordinates 58.4843N, 50.794E, origin time t0=01:44:36 (UTC), depth h=4 km, energy class according to T.G. Rautian Kp=10.2/4, local magnitude ML=3.6/5, Ms=2.7/5, error ellipse: Azmajor=60°, Rminor=4.5 km, Rmajor=5.5 km. The earthquake is tectonic and belongs to the Kirov-Kazhim aulacogen of the Volga-Ural anteclise. The area is known for serious historical earthquakes; instrumental disturbances are also regularly recorded here. The previous activation of the aulacogen occurred in 2020, also in its central flank. The occurrence of seismic events indicates that it is a seismically active structure.