Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 109824 10.2205/2026es001127 zfbuiu KAMCHATKA EARTHQUAKE M 8.8 ON JULY 29, 2025 KAMCHATKA EARTHQUAKE M 8.8 ON JULY 29, 2025 KAMCHATKA EARTHQUAKE M 8.8 ON JULY 29, 2025 Anomalous Changes in Ionospheric Parameters During the Preparation and Occurrence of the M8.8 Earthquake and a Series of Earthquakes With M ≥ 6 That Occurred Near the Kamchatka Peninsula From June to September 2025 According to the Data of Satellite Navigation Systems Anomalous Changes in Ionospheric Parameters During the Preparation and Occurrence of the M8.8 Earthquake and a Series of Earthquakes With M ≥ 6 That Occurred Near the Kamchatka Peninsula From June to September 2025 According to the Data of Satellite Navigation Systems https://orcid.org/0000-0002-2049-6176 Бондур Валерий Григорьевич Bondur Valeriy Grigor'evich koshkina_vera@rambler.ru https://orcid.org/0000-0002-9164-5554 Цидилина Марина Николаевна Tsidilina Marina Nikolaevna tsidilina2910@gmail.com https://orcid.org/0000-0001-9921-5965 Воронова Ольга Сергеевна Voronova Olga Sergeevna v_olya86@mail.ru https://orcid.org/0000-0003-0143-281X Гапонова Мария Владимировна Gaponova Mariya Vladimirovna office@aerocosmos.info https://orcid.org/0000-0002-8681-822X Тимошина Галина Андреевна Timoshina Galina Andreevna Научно-исследовательский институт аэрокосмического мониторинга "АЭРОКОСМОС" Москва Россия Institute for Scientific Research of Aerospace Monitoring "AEROCOSMOS" Moscow Russian Federation Научно-исследовательский институт аэрокосмического мониторинга “АЭРОКОСМОС” Россия Institute for Scientific Research of Aerospace Monitoring “AEROCOSMOS” Russian Federation Научно-исследовательский институт аэрокосмического мониторинга “АЭРОКОСМОС” Россия Institute for Scientific Research of Aerospace Monitoring “AEROCOSMOS” Russian Federation Научно-исследовательский институт аэрокосмического мониторинга “АЭРОКОСМОС” Россия Institute for Scientific Research of Aerospace Monitoring “AEROCOSMOS” Russian Federation Научно-исследовательский институт аэрокосмического мониторинга "АЭРОКОСМОС" Россия Institute for Scientific Research of Aerospace Monitoring “AEROCOSMOS” Russian Federation 01 07 2026 01 07 2026 26 2 ES2017 02 02 2026 25 05 2026 https://rjes.ru/en/nauka/article/109824/view

Changes in the altitude profiles of the ionospheric electron density (Ne) and the total electron content (TEC) were detected using satellite navigation system data during the preparation and occurrence of a powerful M8.8 earthquake (July 29, 2025, UTC) and other strong earthquakes of M ≥ 6 that occurred near the Kamchatka Peninsula in June–September 2025. A 9–18% decrease in the ionospheric electron density was detected, occurred 1–5 days before the M8.8 earthquake. A gradual decrease in the total electron content (TEC) began 3 months before the earthquake, ceasing 15 days before the event. Using the Long Short-Term Memory and Autoencoder neural networks, anomalies were identified in the time series of normalized values of the total electron content (NTEC) of the ionosphere during the preparation of earthquakes of M ≥ 6 that occurred in June–September 2025 near the Kamchatka Peninsula. The pattern of the anomalous variations in ionospheric parameters identified in this research corresponds to the characteristics of ionospheric anomalies during the preparation and occurrence of strong seismic events presented in earlier works.

Changes in the altitude profiles of the ionospheric electron density (Ne) and the total electron content (TEC) were detected using satellite navigation system data during the preparation and occurrence of a powerful M8.8 earthquake (July 29, 2025, UTC) and other strong earthquakes of M ≥ 6 that occurred near the Kamchatka Peninsula in June–September 2025. A 9–18% decrease in the ionospheric electron density was detected, occurred 1–5 days before the M8.8 earthquake. A gradual decrease in the total electron content (TEC) began 3 months before the earthquake, ceasing 15 days before the event. Using the Long Short-Term Memory and Autoencoder neural networks, anomalies were identified in the time series of normalized values of the total electron content (NTEC) of the ionosphere during the preparation of earthquakes of M ≥ 6 that occurred in June–September 2025 near the Kamchatka Peninsula. The pattern of the anomalous variations in ionospheric parameters identified in this research corresponds to the characteristics of ionospheric anomalies during the preparation and occurrence of strong seismic events presented in earlier works.

 Remote sensing ionospheric electron density total electron content seismo-ionospheric coupling ionospheric anomalies Kamchatka megathrust earthquake Remote sensing ionospheric electron density total electron content seismo-ionospheric coupling ionospheric anomalies Kamchatka megathrust earthquake The research was carried out in the framework of the state assignment of ISR “AEROCOSMOS”. The research was carried out in the framework of the state assignment of ISR “AEROCOSMOS”.

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