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The Earth's interior layers, atmosphere, ionosphere, and magnetosphere (EAIM) constitute an interconnected system that is open, dynamic, and nonlinear. In this paper, the response of the ionosphere to a moderate earthquake of Richter magnitude M ≈ 6.6 that occurred on 5 September 2018 in Japan was revealed. A multi-frequency, multiple-path coherent radio system at Harbin Engineering University (HEU complex) was used to observe the time-varying characteristics of HF radio waves along 14 radio propagation paths over the People's Republic of China. The Doppler spectra, the Doppler shift of the main mode frequency, and signal amplitudes are analyzed in the frequency range of 6-7 MHz in this paper. Our findings show that the seismic shock was followed by the spreading of Doppler spectra, and the Doppler frequency shift of the main mode varying with time in a quasi-periodic manner with an approximate period of 3 minutes for infrasound and 20-30 minutes for atmospheric gravity waves. The delay time of the assumed response and the apparent speed of propagation of the disturbances were estimated. Two additional moderate earthquakes with epicenters underwater were used for comparison to analyze the influence of geographical factors. Ionograms are used to analyze the effect of ionospheric structure on disturbance propagation. Our study highlights the need to explore the direct and reverse, positive and negative linkages among the subsystems within the EAIM system to better understand the dynamics of this interconnected system., {"references":["Chernogor, L.F. (2011). The Earth–atmosphere–geospace system: main properties and processes. International Journal of Remote Sensing, 32 (11), 3199-3218.","Chernogor, L.F., Garmash, K.P., Guo, Q., Luo, Y., Rozumenko, V. T. & Zheng, Y. (2020). Ionospheric storm effects over the People's Republic of China on 14 May 2019: Results from multiple path multifrequency oblique radio sounding. Advances in Space Research, 66 (2), 226–242.","Guo, Q., Chernogor, L. F., Garmash, K. P., Rozumenko, V. T. & Zheng, Y. (2019). Dynamical processes in the ionosphere following the moderate earthquake in Japan on 7 July 2018.// Journal of Atmospheric and Solar-Terrestrial Physics, 186, 88 – 103.","Guo, Q., Chernogor, L. F., Garmash, K. P., Rozumenko, V. T. & Zheng, Y. (2020). Radio Monitoring of Dynamic Processes in the Ionosphere over China during the Partial Solar Eclipse of 11 August 2018. Radio Science, 55, e2019RS006866.","Luo, Y., Chernogor, L.F., Garmash, K.P., Guo, Q. & Zheng, Y. (2020a). Seismic-ionospheric effects: results of radio soundings at oblique incidence. Radio Physics and Radio Astronomy, 25 (3), 218-230.","Luo, Y., Chernogor L.F. & Garmash, K.P. (2020b). Geomagnetic effect of Turkish earthquake of January 24, 2020. Radio Physics and Radio Astronomy, 25 (4), 276-289."]}

The cause of a geospace storm is solar storms. Solar flares, coronal mass ejections, and high-speed streams lead to various effects in the Sun–interplanetary-medium–magnetosphere–ionosphere–atmosphere–Earth (inner shells) system (SIMMIAE) As a result, geospace storms arise, which are comprised of synergistically interacting storms in the magnetic field, the ionosphere, the atmosphere, and in an electric field of magnetospheric, ionospheric, and atmospheric origins [1, 2]. The effects of geospace storms are highly diverse and depend on the characteristics of the solar storm, the solar wind (SW) parameters, the state of the geospheres, the position in the solar activity cycle, the time of year and day, the means used to observe, and on the geographic and geomagnetic coordinates of the observation site. The aim of the work is to present general information about the geospace storm, and the results of the analysis of the features of August 5–6, 2019 magnetic and ionospheric storms., {"references":["Chernogor, L.F. & Domnin, I.F. (2014). Physics of Geospace Storms. V. N. Karazin Kharkiv National University Publ, Kharkiv, Ukraine.","Chernogor, L.F. (2021). Physics of geospace storms. Space Sci. Tech. 27(1), 3–77.","Chernogor, L.F., Garmash, K.P., Guo, Q., Luo, Y., Rozumenko, V.T. & Zheng, Y. (2020). Ionospheric storm effects over the People's Republic of China on 14 May 2019: Results from multipath multi-frequency oblique radio sounding. Adv. Space Res. 66(2), 226–242.","Luo, Y., Chernogor, L.F., Garmash, K.P., Guo, Q., Rozumenko, V.T., Zheng, Yu. (2021). Dynamic processes in the magnetic fifield and in the ionosphere during the 30 August–2 September 2019 geospace storm: inflfluence on high frequency radio wave characteristics. Ann. Geophys. 39(4), 657–685.","Luo, Y., Guo, Q., Zheng, Y., Garmash, K.P., Chernogor, L.F. & Shulga, S.N. (2021). Geospace storm effects on August 5–6 2019. Space Sci. Tech. 27(2), 45–69."]}