The March 29, 2019 Earthquake in the Western Part of the Tunka Rift Basin System: Source Parameters and Macroseismic Effects

Abstract

The paper considers one of the perceptible earthquakes that occurred on March 29, 2019, in the western part of the Tunka rift basin system. The epicenter of this seismic event was localized within the Hoytogol basin. The earthquake source parameters were as follows: hypocentral depth (h = 36–37 km), scalar seismic moment (M0 = 1.6 × 1016 N m), moment magnitude (Mw = 4.8), and focal mechanism—were determined using joint inversion of surface wave amplitude spectra and polarities of P-wave first arrivals. The focal mechanism demonstrates the predominance of combined thrust and strike-slip movements, indicating uplifting tectonic movements in the Hoytogol basin. The shaking from the earthquake was felt within a vast area, with an intensity of up to I = III at epicentral distances up to 490 km. Macroseismic data were obtained using different methods, including an interactive questionnaire hosted on the website of the Baikal Branch of GS RAS. Analysis of the macroseismic data made it possible to formulate the goal of refining the regional macroseismic field equation.