Number of views of the article:

UDC 550.844+546.791.027+632.126

https://doi.org/10.26516/2541-9641.2026.2.35

EDN: IFEGNU

Impulses and Arc Distribution of Earthquake in the Baikal Rift System: Real-Time Monitoring Oxidation-Reduction Potential in Groundwater (April–July of 2026)

S.V. Rasskazov^1,2, S.V. Snopkov^2,3, I.A. Aslamov⁴, E.P. Chebykin¹, A.M. Ilyasova¹

¹Institute of the Earth's Crust SB RAS, Irkutsk, Russia

²Irkutsk State University, Irkutsk, Russia

³Irkutsk National Research Technical University, Irkutsk, Russia

⁴Limnological Institute SB RAS, Irkutsk, Russia

Abstract. Weekly temporal variations in the energy class of earthquakes in the east, west, and center of the Baikal Rift System (BRS) are analyzed together with real-time records of the oxidation-reduction potential (ORP) of groundwater at the BRS sensitive point to earthquakes (Kultuk area) in April–July 2026. Two seismic impulses are detected in February–June: the first in the east of the BRS from March 17 to April 24 (the MA impulse), and the second in the center of the BRS from April 28 to June 17 (the AJ impulse), with a transition to combined events in the east and center. The MA impulse develops from preceding ordered weak earthquakes along the entire BRS length to dispersed earthquake epicenters in the east. The AJ impulse denotes a concentration of earthquake epicenters in the BRS center. The development of seismic impulses in the east and center results in a grouping of seismic events with a weekly quasi-periodicity, with a uniform distribution of events in the BRS west. The current increase in ORP in groundwater along the marginal Obruchev Fault of the South Baikal Basin in late June and early July, reflecting increasing compression, is accompanied by a decrease in ORP in groundwater at the Kultuk tectonic step of its axial portion, indicating increased extension. This crustal state indicates the occurrence of seismogenic strike-slip displacement at the Kultuk area that corresponds to one of the seismic reactivation scenarios for the BRS. This scenario was realized in the Kyren earthquake of July 13, 2026, with an elevated energy class (K = 12.9). The epicenters of earthquakes of elevated energy class (K=11.0–12.9) form a migration arc with a common Euler pole of rotation. The arc distribution of the epicenters of the BRS earthquakes, caused by the forces of the Japan-Baikal geodynamic corridor, is realized first (in the time interval 01.02.–13.03.2026) by weak seismic events, and then (in the time interval 18.06.–13.07.2026) by events of an increased energy class.

Keywords: groundwater, monitoring, oxidation-reduction potential, earthquakes, Baikal

References

Earthquake epicenter map. Irkutsk: Baikal branch of the Federal Research Center Unified Geophysical Service of the Russian Academy of Sciences, 2026. http://www.seis-bykl.ru

Freund F. Earthquake forewarning – A multidisciplinary challenge from the ground up to space // Acta Geophysica. 2013. V. 61, no. 4. P. 775–807. DOI: 10.2478/s11600-013-0130-4.

Lukhnev A.V., Sankov V.A., Miroshnichenko A.I., Ashurkov S.V., Byzov L.M., Sankov A.V., Bashkuev Yu.B., Dembelov M.G., Kale E. Modern deformations of the earth's crust in the junction area of rift segments of the central part of the Baikal rift system according to GPS geodesy data // Geology and Geophysics. 2013. Vol. 54. No. 11. P. 1814–1825.

Rasskazov S.V., Chuvashova I.S. Volcanism and transtension in the northeastern Baikal Rift System. Novosibirsk, Academic Publishing House «GEO», 2018. 384 p. doi: 10.21782/B978-5-6041446-3-3

Rasskazov S.V., Aslamov I.A., Snopkov S.V., Arkhipenko V.I., Ilyasova A.M., Chebykin E.P. First experience in real-time monitoring of coseismic and aseismic ORP, pH, and temperature variations in groundwater from the Kultuk reservoir (Baikal Rift System) // Geology and Environment. 2023а. Vol. 3, No. 4. P. 161–181. https://doi.org/10.26516/2541-9641.2023.4.161

Rasskazov S.V., Aslamov I.A., Snopkov S.V., Chebykin E.P., Ilyasova A.M., Chuvashova I.S. From magnetic storm control of weak earthquakes in the Baikal Rift System to dominant seismic impulses of the Japan-Baikal geodynamic corridor: real-time monitoring of groundwater oxidation-reduction potential in early 2026 // Geology and Environment. 2026. Vol. 1 , No. 1. P. 56–90. DOI 10.26516/2541-9641.2026.1.56.

Rasskazov S.V., Chebykin E.P., Ilyasova A.M., Snopkov S.V., Chuvashova I.S. Expanding seismicity and paragenetic variations in groundwater composition in the Baikal rift system in 2020–2025: assessment of the current state of the earth's crust // Geology and Environment. 2025. Vol. 5, No. 2. P. 69–123. DOI 10.26516/2541-9641.2025.2.69.

Rasskazov S.V., Ilyasova A.M., Bornyakov S.A., Chebykin E.P. Goryachinsk reactivation of the Yambui transtension zone in 2013–2015: Coseismic chemical hydrogeodynamics of groundwater on the southeastern coast of Middle Baikal // Geology and Environment. 2023б. Vol. 3, No. 4. P. 108–145. https://doi.org/10.26516/2541-9641.2023.4.108

Rasskazov S.V., Ilyasova A.M., Bornyakov S.A., Snopkov S.V., Chuvashova I.S., Chebykin E.P. Hydrogeochemical responses of groundwater from station 184 in 2020-2021 on seismogenic deformations of the Baikal-Khubsugul reactivation // Geology and Environment. 2022. Vol. 2, No. 4. P. 26–52. DOI 10.26516/2541-9641.2022.4.26

 

Rasskazov Sergei Vasilevich,

doctor of geological and mineralogical sciences, professor,

664025, Irkutsk, Lenin st., 3,

Irkutsk State University, Faculty of Geology,

Head of Dynamic Geology Char,

664033, Irkutsk, Lermontov str., 128,

Institute of the Earth's Crust SB RAS,

Head of the Laboratory for Isotopic and Geochronological Studies,

tel.: (3952) 51–16–59,

email: rassk@crust.irk.ru

 

Snopkov Sergei Viktorovich,

Candidate of Geological and Mineralogical Sciences,

664025, Irkutsk, Lenin sr., 3,

Irkutsk State University, Faculty of Geology,

Associate Professor,

664074, Irkutsk, Kurchatov st., 3,

Siberian School of Geosciences, Irkutsk National Research Technical University,

Leading Researcher,

email: snopkov_serg@mail.ru.

 

Aslamov Ilya Aleksandrovich,

Candidate of physical and mathematical sciences,

664033, Irkutsk, Ulan-Batorskaya st., 3,

Limnological Institute SB RAS,

Head of laboratory of hydrology and hydrophysics,

email: ilya_aslamov@bk.ru

 

Chebykin Eugene Pavlovich,

Candidate of Chemical Sciences,

664033, Irkutsk, Lermontov st., 128,

Institute of the Earth's Crust SB RAS,

leading specialist,

email: epcheb@yandex.ru

 

Ilyasova Aigul Maratovna,

candidate of geological and mineralogical sciences,

664033, Irkutsk, Lermontov st., 128,

Institute of the Earth's Crust SB RAS,

leading engineer,

email: ila@crust.irk.ru

 

Read the full article (Russian)