Features of Seismic Impact Attenuation of the Russian Platform and Ural Earthquakes

Abstract

The article analyzes the macroseismic impact of earthquakes that occurred in the late 20th and early 21st centuries on the Russian Platform and in the Urals. The relationships between seismic intensity I, magnitude M, and hypocentral distance r, according to the Blake–Shebalin equation, were established for five regions of the study area. For the first time, the coefficients of individual macroseismic field equations for the Ural near-surface and deeper sources were obtained (h ≤ 1 km: b = 1.5, v = 2.43, c = 1.01; h > 1 km: b = 1.5, v = 2.9, c = 2.13). The possibility of using the Blake–Shebalin equation with average coefficients (b = 1.5, v = 3.5, c = 3) was confirmed for earthquakes in southern Russian Platform. The low attenuation of the intensity of Baltic Sea earthquakes is established for the Eastern Baltics. The coefficient v = 2.48 in the obtained equation is similar to v = 2.7 recommended for this territory in the new Russian and Interstate Standard “Earthquakes: Macroseismic Intensity Scale” (2019). However, the level of seismic impact according to the established equation is higher than that predicted by this standard. The reduced attenuation coefficients for earthquakes in the eastern Russian Platform and induced events (h ≤ 1 km) in the eastern Baltic Shield have been obtained: v = 2.3 and v = 3.02, respectively. However, due to the lack of field data, these results need to be refined. New dependences are recommended for more accurate prediction of seismic impact from earthquakes in these regions.