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Omnidirectional dynamics of the Earth's crust seasonal deformation and the aerosol output decrease in the adit over the Elbrus volcano magmatic chamber
S. M. Pershin1, M.Ya. Grishin1, V. A. Zavozin1, V. S. Makarov2, V. N. Lednev1, A.V. Myasnikov3
1-Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, 38 Vavilova
street, Russia
2-Space Research Institute of the Russian Academy of Sciences, Moscow, Russia 3-Sternberg Astronomical Institute Moscow State University Moscow, Russia
E-mail: pershin@kapella.gpi.ru
It is known [1] that seasonal Earth's crust deformations caused by temperature seasonal changes are modulated by Solar-lunar tides with diurnal and semi-diurnal waves P1K1 and Si. Recently, we have discovered that the Earth's crust autumn deformation is accompanied by a decrease in the aerosol output in the dead-end adit of the Baksan Neutrino Observatory (BNO) (43°14'57.7"N, 42°43'19.5"E) over the Elbrus volcano magmatic chamber c. Aerosol output variations were monitored by a specially designed lidar with eye-safe laser irradiation level (<1 ^J/cm2) and a single photon avalanche photodiode as a detector. In the measurements the lidar emitted 100000 laser pulses at 10 kHz repetition rate every 30 minutes. Note that the lidar integrates the contributions of all magmatic gases and water vapor that carry aerosol in the adit volume over the whole lidar sensing path which increases the lidar sensitivity to geodynamic processes. The experimental setup and procedure are described in detail in [3].
Fig.1. (a) Seasonal Earth's crust deformation (Aug-Nov 2019) measured by a 75-m laser strainmeter in BNO (black thin line) and the aerosol output (red thick line), the dashed line represents the average deformation trend; (b) a detailed picture of the Earth's crust deformation and the aerosol output in the vicinity of the fall equinox (Sep 5 - Oct 8, 2019).
The seasonal Earth's crust deformation is indicated by the strainmeter measuring arm length shortening by ~4 ^m/day. The data analysis has revealed that the crust deformation and aerosol output in Aug-Nov 2019 are symbatic (see Fig.1(a)). Simultaneously, we have revealed that in the vicinity of the fall equinox (Sep 5 - Oct 8, 2019) both dependences omnidirectional deviate from the general trend (dashed line in Fig.1(a)) stronger than the amplitude of deformation waves caused by temperature and Solar-lunar tides (Fig.1(b)) [2] and humidity.
The authors are grateful to the Russian Science Foundation for financial support of the study (project №19-19-00712).
[1] Melchior P. J., 1983, The Tides of the Planet Earth, Oxford: Pergamon Press; Melchior Paul J., "The Earth Tides," Pergamon Press, Oxford, 458 pages, 1966.
[2] Milyukov V.K., Myasnikov A.V., "Metrological characteristics of the Baksan laser interferometer," Measurement Techniques, Instrument Society of America, vol. 48, no. 12, pp. 1183-1190, (2012).
[3] Pershin S.M., Sobisevich A.L., Grishin M.Ya., Gravirov V.V., Zavozin V.A., Kuzminov V.V., Likhodeev D.V., Lednev V.N, Makarov V.S., Myasnikov A.V., and Fedorov A.N., Volcanic activity monitoring by unique LIDAR based on a diode laser, Laser Phys. Lett. 17(11), 115607 (7pp), (2020).
