SEISMICITY of the NORTH-EAST of RUSSIA in 2016–2017

Abstract

The results of seismic monitoring of the region of Magadan, Chukotka Autonomous Area and the shelf of adjacent seas (the Okhotsk, Chukchi, Bering and East Siberian seas) are considered. There were 14 seismic stations working in the region in 2016–2017. The new station “Talon” was opened on the Okhotsk sea coast. The catalog includes information about 577 earthquakes with energy classes KR=4.6–12.7. As usual, most of them (88 %) are located 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 equal to ΣЕ=1.861013 J. The energy representativeness map of earthquakes with Kmin=5–10 was built. It shows that the described network of stations records earthquakes with Kmin=7 at the Magadan region, with Kmin=8 in the Okhotsk sea without omissions. In 2016–2017 the strongest earthquake with KR=12.7 (mbMOS=4.8) occurred on November 5 in Chukchi Peninsula. Five earthquakes with the intensity I=2–4 (according to the Russian Seismic Intensity scale introduced in 2017) were felt in the North East settlements. The maximum shaking intensity of I=4 was observed in the Beringovskiy settlement (∆=22 km). Joint map of epicenters of the Magadan region earthquakes and tectonic zoning scheme shows that 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 2016–2017 according to the “SOUS-09” scale was assessed as "background average" for the observation period from 1968 to 2017. Spatially, all earthquakes are traditionally concentrated in large seismogenic belts: Chersky, North-Okhotsk and Trans-Beringian.