Ono, Yuya, Yuichi Ida, Yasushi Kasahara, Yasuhide Hobara, Masashi Hayakawa, Alexander Rozhnoi, Maria Solovieva, Oleg A. Molchanov, and Kenji Ohta. “Ionospheric Perturbations Associated With Two Huge Earthquakes in Japan, Using Principal Component Analysis for Multiple Subionospheric VLF LF Propagation Paths”. Annals of Geophysics 55, no. 1 (April 24, 2012). Accessed April 11, 2026. https://www.annalsofgeophysics.eu/index.php/annals/article/view/5329.