The study of the phenomenon of migrating seismicity in the epicentral fields of various seismically active regions of the Earth is the subject of many works. Chains of “migrations” of earthquakes are identified using various methods and are often explained by the passage of deformation waves in the Earth’s lithosphere. This paper presents the results of studying the spatiotemporal distribution of quasi-linear chains of earthquakes in the Baikal region using statistical approaches and a large amount of initial data on earthquakes of representative energy classes. It is shown that the chains are formed mainly within the Baikal Rift System (BRS) and are confined to zones of seismotectonic destruction of the lithosphere. When studying the lengths of earthquake chains, five maxima of the distribution of chains were revealed, three of which correspond to possible geological and geophysical processes in the BRS lithosphere.

Anna A. Kakourova
Сandidate of Geological and Mineralogical Sciences
Junior Researcher
The Institute of the Earth’s crust SB RAS
128, Lermontov St., Irkutsk, 664033, Russia
e-mail: anna2015@crust.irk.ru
Web of Science ResearcherID: ABG-2692-2020

Evgenii V. Bryzhak
Сandidate of Geological and Mineralogical Sciences
Senior researcher head of the laboratory of engineering seismology and seismogeology
The Institute of the Earth’s crust SB RAS
128, Lermontov St., Irkutsk, 664033, Russia
e-mail: bryzhak@crust.irk.ru
ORCID: 0000-0001-7550-4447, SPIN-код: 3053-8213

Vladimir M. Dem’yanovich
Lead Engineer
The Institute of the Earth’s crust SB RAS
128, Lermontov St., Irkutsk, 664033, Russia
e-mail: vmdem@crust.irk.ru

Anna A. Klyuchevskaya
Candidate of Biological Sciences
Lead Engineer
The Institute of the Earth’s crust SB RAS
128, Lermontov St., Irkutsk, 664033, Russia
e-mail: annakl@crust.irk.ru

1. Altae-Sayanskii filial FGBU FITS «Edinaya geofizicheskaya sluzhba Rossiiskoi akademii nauk» [Altai-Sayan Branch of the Federal Research Center “Unified Geophysical Service of the Russian Academy of Sciences”]. Available at: http://www.asgsr.ru (accessed 03.13.2022).
2. Baikal’skii filial FGBU FITS «Edinaya geofizicheskaya sluzhba Rossiiskoi akademii nauk» [Baikal Branch of the Federal Research Center “Unified Geophysical Service of the Russian Academy of Sciences”]. Available at: http://www.seis-bykl.ru (accessed 13.13.2022).
3. Bol’shev L.N., Smirnov N.V. Tablitsy matematicheskoi statistiki [Mathematical statistics tables]. Moscow: Nauka; 1983. 417 p.
4. Boyarov A.A. Randomizirovannyi algoritm stokhasticheskoi approksimatsii dlya klasterizatsii smesi gaussovykh raspredelenii pri razrezhennykh parametrakh [Randomized Stochastic Approximation Algorithm for Clustering a Mixture of Gaussian Distributions with Sparse Parameters]. Stokhasticheskaya optimizatsiya v informatike. 2019;15(1):3–19.
5. Bykov V.G. Strain waves in the Earth: theory, field data, and models. Russian Geology and Geophysics. 2005;46(11):1176–1190.
6. Bykov V.G., Merkulova T.V. Earthquake migration and hidden faults in the Priamurye region. Russian Journal of Pacific Geology. 2020;14(4):326–339. DOI: 10.1134/S1819714020040028.
7. Vikulin A.V. Physics of wave seismic process. Petropavlovsk-Kamchatsky: KGPU; 2003. 150 p.
8. Vikulin A.V., Akmanova D.R., Vikulina S.A., Dolgaya A.A. Migration of seismic and volcanic activity as display of wave geodynamic process. Geodynamics & Tectonophysics. 2012;3(1):1–18. DOI:10.5800/GT-2012-3-1-0058.
9. Vil’kovich E.V, Guberman Sh.A., Keilis-Borok V.I. Volny tektonicheskikh deformatsii na krupnykh razlomakh [Tectonic deformation waves at large faults]. Doklady of the Academy of Sciences of the USSR. 1974;219(1):77–80.
10. Golenetskii S.I. Zemletryaseniya yuga Sibirskoi platformy po instrumental’nym seismologicheskim nablyudeniyam [Earthquakes in the South of the Siberian Platform Based on Instrumental Seismological Observations]. Vulkanologiya i sejsmologiya. 2001;(6):68–77.
11. Guberman Sh.A. Zemletryaseniya, neravnomernost’ vrashcheniya Zemli i D-volny [Earthquakes, uneven rotation of the Earth and D-waves]. Doklady of the Academy of Sciences of the USSR. 1979;230(6):1314–1317.
12. Kakourova A.A., Kluchevskii A.V. Migrating seismicity in the lithosphere of the Baikal rift zone: spatial-temporal and energy distribution of earthquake chains. Russian Geology and Geophysics. 2020;61(11):1298–1312. DOI: 10.15372/GiG2019164.
13. Klyuchevskii A.V., Dem’yanovich V.M., Klyuchevskaya A.A., Zuev F.L., Kakourova A.A., Chernykh E.N., Bryzhak E.V. Gruppiruyushchayasya seismichnost’ Pribaikal’ya [Grouping Seismicity of the Baikal Region]. In: Aktual’nye problemy nauki Pribaikal’ya. Bychkov I.V., Kazakov A.L., eds. Iss. 1. Irkutsk: IG SO RAN; 2015. pp. 139–143.
14. Klyuchevskii A.V., Kakourova A.A. Investigation of migrating seismicity in the lithosphere of the Baikal rift zone. Doklady Earth sciences. 2019;488(1):1128–1133. DOI: 10.1134/S1028334X19090265.
15. Klyuchevskii A.V., Kakourova A.A. The main criteria for allocating earthquake chains in the Baikal Region lithosphere. // The Bulletin of Irkutsk State University. Series: Earth Sciences. 2018;23:64–73. DOI: 10.26516/2073-3402.2018.23.64.
16. Levina E.A., Ruzhich V.V. The seismicity migration study based on space-time diagrams. Geodynamics & Tectonophysics. 2015;6(2):225–244. DOI: 10.5800/GT-2015-6-2-0178.
17. Lemeshko B.Yu., Lemeshko S.B. Distribution models for nonparametric tests for fit in verifying complicated hypotheses and maximum-likelihood estimators. Part 1. Measurement techniques. 2009;52(6):555–565. DOI: 10.1007/s11018-009-9330-3.
18. Lukk A.A. Prostranstvenno-vremennye posledovatel’nosti slabykh zemletryasenii Garmskogo raiona [Spatiotemporal sequences of weak earthquakes in the Garm Region]. Fizika Zemli. 1978;(2):25–37.
19. Melnikova V.I., Seredkina A.I., Gileva N.A. Spatio-temporal patterns of the development of strong seismic activations (1999-2007) in the northern Baikal area. Russian geology and geophysics. 2020;61(1):96–109. DOI: 10.15372/RGG2019103.
20. Misharina L.A., Solonenko A.V. Vliyanie blokovoi delimosti zemnoi kory na raspredelenie seismichnosti v Baikal’skoi riftovoi zone [Influence of the block divisibility of the earth’s crust on the distribution of seismicity in the Baikal rift zone]. In: Seismichnost’ Baikal’skogo rifta. Prognosticheskie aspekty. Pavlov O.V., Misharina L.A., eds. Novosibirsk: Nauka; 1990. p. 70–78.
21. Novopashina A.V. Technique of the Cis-Baikal seismic activity migration isolation by GIS. Geoinformatika. 2013;(1):33–36.
22. Novopashina A.V., San’kov V.A. Velocities of slow migration of seismic activity in Gis-Baikal region. Geodynamics & Tectonophysics. 2010;1(2):197–203. DOI: 10.5800/GT-2010-1-2-0015.
23. Computer program Chain”: certificate of state registration 2016661616 Rus. Federation. A.A. Kakourova, A.V. Kluchevskii; applicant and copyright holder: the Institute of the Earth’s crust SB RAS. No. 2016519051; claimed 24.08.2016; published 14.20.2016.
24. Radziminovich N.A., Ochkovskaya M.G. Identification of earthquake aftershock and swarm sequences in the Baikal rift zone. Geodynamics & Tectonophysics. 2013;4(2):169-186. DOI: 10.5800/GT-2013-4-2-0096.
25. Seminskii K.Zh., Radziminovich Ya.B. Seismicity of the southern Siberian platform: spatiotemporal characteristics and genesis. Izvestia, Physics of the Solid Earth. 2007;43(9):726–737. DOI: 10.1134/S1069351307090029.
26. Sposob opredeleniya tsepochek zemletryasenii v ehpitsentral’nom pole seismichnosti [Method for determining earthquake chains in an epicentral seismicity field]: patent 2659334 Rus. Federation. A.V. Klyuchevskii, A.A. Kakourova, A.A. Klyuchevskaya, V.M. Dem’yanovich, E.N. Chernykh; applicant and patentee: the Institute of the Earth’s crust SB RAS. No. 2017131805. Claimed 09.11.2017; published on 29.07.2018. Bulletin No. 19.
27. Tat’kov G.I., Tubanov Ts.A. Razvitie seismicheskogo protsessa i monitoring v blizreal’nom vremeni zony Yuzhnobaikal’skgo zemletryaseniya 1999 goda [Development of the seismic process and monitoring in near real time of the zone of the South Baikal earthquake of 1999]. Buryat State University Bulletin. Biology. Geography. 2004;(3):35–46.
28. Ulomov V.I. Volny seismogeodinamicheskoi aktivizatsii i dolgosrochnyi prognoz zemletryasenii [Seismogeodynamic activation waves and longtermforecast of earthquakes]. Fizika Zemli. 1993;(4):43–53.
29. Ulomov V.I., Danilova T.I., Medvedeva N.S., Polyakova T.P. Seismogeodynamics of lineament structures in the mountainous regions bordering the Scythian-Turan plate. Izvestia, Physics of the Solid Earth. 2006;42(7):551–566. DOI: 10.1134/S1069351306070032.
30. Sherman S.I. Izbrannye trudy. Tektonofizika razlomoobrazovaniya i soputstvuyushchikh protsessov v litosfere [Selected works. Tectonophysics of Faulting and Associated Processes in the Lithosphere]. Irkutsk: IZK SO RAN; 2017. 1476 p.
31. D’Agostino R.B. An omnibus test of normality for moderate and large sample size. Biometrika. 1971;58(2):341–348.
32. D’Agostino, R., Pearson E.S. Tests for departure from normality. Biometrika. 1973;60(3):613-622.
33. Dempster A.P., Laird N.M., Rubin D.B. Maximum likelihood from incomplete data via the EM algorithm. Journal of the Royal Statistical Society: Series B (Methodological). 1977;39(1):1–22.
34. King A.P., Eckersley R.J. Statistics for Biomedical Engineers and Scientists. How to Visualize and Analyze Data. London: Academic Press; 2019. 249 p.
35. Klyuchevskii A.V. Rifting Attractor Structures in the Baikal Rift System: Location and Effects. Journal of Asian Earth Sciences. 2014;88:246–256. DOI: 10.1016/j.jseaes.2014.03.009.
36. Kolmogorov A.N. Sulla determinazione empirica di una legge di distribuzione. Giornale dell` Istituto Italiano degli Attuari. 1933;4(1):83–91.
37. Mogi K. Migration of seismic activity. Bulletin of the Earthquake Research Institute. 1968;46:53–74.
38. Novopashina A.V., Lukhneva O.F. The propagation velocity of seismic activity migrating along the directions of the geodynamic forces prevailing in the northeastern Baikal rift system, Russia. Annals of geophysics. 2021;64(4):SE436. DOI: 10.4401/ag-8654.
39. Pollitz F., Vergnolle M., Calais E. Fault interaction and stress triggering of twentieth century earthquakes in Mongolia. Journal of Geophysical Research: Solid Earth. 2003;108(B10):2503.
40. Richter C.F. Elementary Seismology. London: Freeman; 1958. 768 p.
41. Scott D.V. Multivariate Density Estimation: Theory, Practice, and Visualization. New York: Wiley; 1992. 352 p.
42. Shapiro S.S., Wilk M.B. An analysis of variance test for normality (complete samples). Biometrika. 1965;52(3/4):591–611. DOI: 10.2307/2333709.
43. Titterington D.M., Smith A.F.M., Makov U.E. Statistical Analysis of Finite Mixture Distributions. Chichester: Wiley; 1987. 243 p.
44. Wilcox R.R. Introduction to Robust Estimation and Hypothesis Testing. Waltham: Academic Press, 2022. 689 p.