SEISMICITY of the NORTH-EAST of RUSSIA in 2018–2019

Abstract

The results of seismic monitoring of the Magadan region, Chukotka Autonomous Area and the shelf of adjacent Okhotsk, Chukchi, Bering and East Siberian seas are considered. There were 14 seismic stations working in the region. The catalog includes information about 644 earthquakes with energy classes KR=4.8–13.2. As usual, most of them (77 %) are localized in the Kolyma region (area № 2).The additional catalog contains information about 12 earthquakes in the Chukchi. The total seismic energy released within the region’s borders was ΣЕ=2.671013 J. The classification of Russian North-East earthquakes was performed using energy classes KR of T.G. Rautian’s scale. According to the earthquake energy representativeness map, the regional network of stations records without omissions the earthquakes with Kmin=7on the territory of Magadan region, with Kmin=8 in the Okhotsk sea and with Kmin=10 in the Chukchi. The strongest earthquake of 2018–2019 with KR=13.2 (MPSP=5.1, MS=4.0) occurred on July 5, 2019 in in the Kolyma area. 14 earthquakes with intensity I=2–5 of the Russian Seismic Intensity Scale (SIS-2017) were felt in North East settlements. Epicenters of Magadan region earthquakes were plotted on the tectonic zoning scheme. Most earthquakes are confined to the largest deep faults in the northwestern and sublatitudinal directions. All hypocenters are located within the earth's crust. The seismicity level of the North-East of Russia in 2018–2019 according to the “SOUS’09” scale was assessed as "background average one" for the observation period from 1968 to 2019. Spatially, all earthquakes in the North-East of Russia are traditionally concentrated in large seismogenic belts: Chersky, North-Okhotsk and Trans-Beringian.