{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T21:17:49Z","timestamp":1790630269889,"version":"4.1.0"},"reference-count":42,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,1,1]],"date-time":"2022-01-01T00:00:00Z","timestamp":1640995200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002322","name":"Coordena\u00e7\u00e3o de Aperfeicoamento de Pessoal de N\u00edvel Superior","doi-asserted-by":"publisher","award":["88887.351785\/2019-00"],"award-info":[{"award-number":["88887.351785\/2019-00"]}],"id":[{"id":"10.13039\/501100002322","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Earthquakes are known to generate disturbances in the ionosphere. Such disturbances, referred to as co-seismic ionospheric disturbances, or ionoquakes, were previously reported for large earthquakes with magnitudes Mw\u2265 6.6. This paper reports ionoquakes associated with the Ridgecrest earthquakes of magnitude (Mw=6.4), that occurred on 4 July 2019 in California, USA. The ionoquakes manifested in total electron content (TEC) in the form of traveling ionospheric disturbances (TIDs) within 1 h from the mainshock onset. These seismic-origin TIDs have unique wave characteristics that distinguish them from TIDs of non-seismic origin arising from a moderate geomagnetic activity on the same day. Moreover, in the space-time domain of the detection of seismic-origin TIDs, TIDs are absent on the day before and day after the earthquake day. Their spectral characteristics relate them to the Earth\u2019s normal modes and atmospheric resonance modes. We found the ground velocity associated with the mainshock, rather than the ground displacement, satisfies the threshold criteria for detectable ionoquakes in TEC measurements. Numerical simulation suggested that the coupled seismo\u2013atmosphere\u2013ionosphere (SAI) dynamics energized by the atmospheric waves are responsible for the generation of ionoquakes. This study\u2019s findings demonstrate the potential of using TEC measurement to detect the ionospheric counterparts of moderate earthquakes.<\/jats:p>","DOI":"10.3390\/rs14010188","type":"journal-article","created":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T23:06:15Z","timestamp":1641769575000},"page":"188","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Ionospheric Disturbances Observed Following the Ridgecrest Earthquake of 4 July 2019 in California, USA"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2172-8290","authenticated-orcid":false,"given":"Saul A.","family":"Sanchez","sequence":"first","affiliation":[{"name":"National Institute for Space Research, Av. dos Astronautas, 1758, Sao Jose dos Campos 12227010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0182-2252","authenticated-orcid":false,"given":"Esfhan A.","family":"Kherani","sequence":"additional","affiliation":[{"name":"National Institute for Space Research, Av. dos Astronautas, 1758, Sao Jose dos Campos 12227010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3819-3835","authenticated-orcid":false,"given":"Elvira","family":"Astafyeva","sequence":"additional","affiliation":[{"name":"Institut de Physique du Globe de Paris, Universit\u00e9 de Paris, CNRS UMR, 7154 Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2756-3826","authenticated-orcid":false,"given":"Eurico R.","family":"de Paula","sequence":"additional","affiliation":[{"name":"National Institute for Space Research, Av. dos Astronautas, 1758, Sao Jose dos Campos 12227010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/S0031-9201(97)00089-7","article-title":"GPS, earthquakes, the ionosphere, and the Space Shuttle","volume":"105","author":"Calais","year":"1998","journal-title":"Phys. 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