THE MARCH 29, 2019 EARTHQUAKE OCCURRED AT THE WESTERN PART
OF THE TUNKA SYSTEM OF THE RIFT BASINS: SOURCE PARAMETERS AND MACROSEISMIC EFFECTS

Ya.B. Radziminovich¹, A.I. Seredkina², V.I. Melnikovа¹, N.A. Gileva³

¹ Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia

² Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, Moscow, Troitsk, Russia

³ Baikal Branch of Federal Research Center «Geophysical Survey of Russian Academy of Sciences», Irkutsk, Russia

Corresponding author: Ya.B. Radziminovich, e-mail: ian@crust.irk.ru

Abstract. We consider one of the remarkable earthquakes occurred on March 29, 2019 at the western part of the Tunka system of the rift basins. The epicenter of the seismic event is localized within the Hoytogol basin. Earthquake source parameters – a hypocentral depth (h = 36–37 km), scalar seismic moment (M₀ = 1.6·10¹⁶ Nm), moment magnitude (M_w = 4.8) and its focal mechanism – were determined using the joint inversion of surface wave amplitude spectra and P-wave first motion polarities. The focal mechanism demonstrates the predominance of the combination of thrust and strike-slip movements that evidences the upward movements in the Hoytogol basin. The earthquake covered a wide area and was felt with intensity up to III at the epicentral distances up to 490 km. Macroseismic data were obtained using different methods including the interactive questionnaire posted on the website of the Baikal branch of FRC GS RAS. Analysis of the macroseismic data allows us to formulate the task concerning the refinement of the regional macroseismic field equation.

Keywords: Tunka system of the rift basins, seismicity, earthquake, macroseismic data, macroseismic equation.

About the authors

RADZIMINOVICH Yan Borisovich – Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences. Russia, 664033, Irkutsk, Lermontova st., 128. E-mail: ian@crust.irk.ru

SEREDKINA Alena Igorevna – Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences. Russia, 108840, Moscow, Troitsk, Kaluzhskoye Highway, 4. E-mail: ale@crust.irk.ru

MELNIKOVA Valentina Ivanovna – Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences. Russia, 664033, Irkutsk, Lermontova st., 128. E-mail: vimel@crust.irk.ru

GILEVA Nadezhda Alekseevna – Baikal Branch of Federal Research Center «Geophysical Survey of Russian Academy of Sciences». Russia, 664033, Irkutsk, Lermontova st., 128. E-mail: nagileva@crust.irk.ru

Cite this article as: Radziminovich Ya.B., Seredkina A.I., Melnikovа V.I., Gileva  N.A. The March 29, 2019 earthquake occurred at the western part of the Tunka system of the rift basins: Source parameters and macroseismic effects, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology). 2020. V. 47, No. 2. P. 64–80 [in Russian]. https://doi.org/10.21455/VIS2020.2-4

English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990