Assessment of quality factor of the crust and the upper mantle in the North-Eastern Caucasus based on the records of seismic station “Makhachkala”

V.I. Kirsanov1, O.V. Pavlenko2

1 Lomonosov Moscow State University, Moscow, Russia

2 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

Corresponding author: O.V. Pavlenko, e-mail: olga@ifz.ru

Abstract. In this paper, we continue studying parameters of propagation of seismic waves in the Northern Caucasus and estimate the quality factor (Q-factor) of the crust and the upper mantle in the vicinity of Makhachkala, which is compared with the previously estimated quality factors in the vicinities of Sochi, Anapa, and Kislovodsk. Based on the records of regional (with epicentral distances < 300 km) earthquakes (MW ~3.9–5.6) obtained by “Makhachkala” seismic station, we obtained the following Q(f) estimates: Q(f) ~96f0.98 (envelope method) and Q(f) ~135f0.72 (code normalization method), and the combined estimate Q(f) ~120f0.8 (at frequencies below ~16 Hz). At lower frequencies, the obtained Q(f) estimates in the vicinity of Makhachkala are slightly higher than similar estimates obtained in the North-Western Caucasus in the vicinities of Sochi, Anapa and Kislovodsk, where Q0 ~55–90 and n ~0,7–1.0. We are planning to verify and probably clarify the obtained estimates of the quality function by stochastic simulation of the records of local earthquakes.

Keywords: quality factor, North-Eastern Caucasus, earthquakes, “Makhachkala” seismic station

About the authors

KIRSANOV Vitali Igorevich – Student, Lomonosov Moscow State University. 119991, GSP-1, Moscow, Leninskie Gory, 1. E-mail: quad.vk@gmail.com

PAVLENKO Olga Vitalievna – Doctor of Physical and Mathematical Sciences, Chief Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. E-mail: olga@ifz.ru

Cite this article as: Kirsanov V.I., Pavlenko O.V. Assessment of quality factor of the crust and the upper mantle in the North-Eastern Caucasus based on the records of seismic station “Makhachkala”, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology). 2019. V. 46, No. 2. P. 60–73. [in Russian]. https://doi.org/10.21455/VIS2019.2-6

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