ANALYSIS OF THE SEISMIC AND IONOSPHERIC EFFECTS OF THE KUDARINSKY EARTHQUAKE ON DECEMBER 9, 2020

According to the data obtained on the equipment of the IEC SB RAS complex monitoring base for hazardous geological processes "Buguldeika" (Shared Research Facilities "Geodynamics and Geochronology" of IEC SB RAS) and Shared Research Facilities "Angara" of ISTP SB RAS an analysis of the characteristics of the Kudarinsky earthquake (09.12.2020) and the behaviour of the ionosphere during this event was carried out. The source parameters of the earthquake were obtained – the seismic moment of the earthquake (M0=3.02·1017 N·m), the moment magnitude (Mw=5.6), the source radius (2.43 km), and the stress drop (1.26 MPa).The analysis of the ionosphere behaviour carried out using GPS/GLONASS receivers did not reveal disturbances caused by the Kudarinsky earthquake, which is most likely due to the relatively small magnitude of this earthquake. An analysis of the observation series related to the Kudarinsky earthquake showed the efficiency of using the Core Facilities Centre equipment and complex monitoring bases for studying seismicity, which is the most dangerous natural process for the Baikal region

АНАЛИЗ СЕЙСМИЧЕСКИХ И ИОНОСФЕРНЫХ ЭФФЕКТОВ КУДАРИНСКОГО ЗЕМЛЕТРЯСЕНИЯ 9 ДЕКАБРЯ 2020 г.

According to the data obtained on the equipment of the IEC SB RAS complex monitoring base for hazardous geological processes "Buguldeika" (Shared Research Facilities "Geodynamics and Geochronology" of IEC SB RAS) and Shared Research Facilities "Angara" of ISTP SB RAS an analysis of the characteristics of the Kudarinsky earthquake (09.12.2020) and the behaviour of the ionosphere during this event was carried out. The source parameters of the earthquake were obtained – the seismic moment of the earthquake (M0=3.02·1017 N·m), the moment magnitude (Mw=5.6), the source radius (2.43 km), and the stress drop (1.26 MPa).The analysis of the ionosphere behaviour carried out using GPS/GLONASS receivers did not reveal disturbances caused by the Kudarinsky earthquake, which is most likely due to the relatively small magnitude of this earthquake. An analysis of the observation series related to the Kudarinsky earthquake showed the efficiency of using the Core Facilities Centre equipment and complex monitoring bases for studying seismicity, which is the most dangerous natural process for the Baikal region.По данным, полученным на оборудовании пункта комплексного мониторинга опасных геологических процессов ИЗК СО РАН «Бугульдейка» (Центр коллективного пользования «Геодинамика и геохронология» ИЗК СО РАН) и Центра коллективного пользования «Ангара» ИСЗФ СО РАН, проведен анализ характеристик Кударинского землетрясения (09.12.2020) и поведения ионосферы во время этого события. Получены значения очаговых параметров землетрясения – сейсмический момент землетрясения (M0=3.02·1017 Н·м), моментная магнитуда (Mw=5.6), размеры очага (2.43 км), величина сброшенного напряжения (1.26 МПа).Проведенный с помощью приемников GPS/ГЛОНАСС анализ поведения ионосферы не выявил возмущений, вызванных Кударинским землетрясением, что, вероятнее всего, обусловлено относительно малой магнитудой этого землетрясения. Анализ рядов наблюдений в отношении Кударинского землетрясения показал эффективность использования оборудования центров коллективного пользования и пунктов комплексного мониторинга для исследования сейсмичности, которая является наиболее опасным природным процессом для Байкальского региона

The MHD nature of ionospheric wave packets excited by the solar terminator

We obtained the first experimental evidence for the magnetohydrodynamic (MHD) nature of ionospheric medium-scale travelling wave packets (MSTWP). We used data on total electron content (TEC) measurements obtained at the dense Japanese network GPS/GEONET (1220 stations) in 2008-2009. We found that the diurnal, seasonal and spectral MSTWP characteristics are specified by the solar terminator (ST) dynamics. MSTWPs are the chains of narrow-band TEC oscillations with single packet's duration of about 1-2 hours and oscillation periods of 10-20 minutes. Their total duration is about 4--6 hours. The MSTWP spatial structure is characterized by a high degree of anisotropy and coherence at the distance of more than 10 wavelengths. The MSTWP direction of travelling is characterized by a high directivity regardless of seasons. Occurrence rate of daytime MSTWPs is high in winter and during equinoxes. Occurrence rate of nighttime MSTIDs has its peak in summer. These features are consistent with previous MS travelling ionosphere disturbance (TID) statistics obtained from 630-nm airglow imaging observations in Japan. In winter, MSTWPs in the northern hemisphere are observed 3-4 hours after the morning ST passage. In summer, MSTWPs are detected 1.5-2 hours before the evening ST occurrence at the point of observations, at the moment of the evening ST passage in the magneto-conjugate point. Both the high Q-factor of oscillatory system and synchronization of MSTWP occurrence with the solar terminator passage at the point of observations and in the magneto-conjugate area testify the MHD nature of ST-excited MSTWP generation. The obtained results are the first experimental evidence for the hypothesis of the ST-generated ion sound waves.Comment: 12 pages, 3 figure