Preliminary analysis of lower ionospheric perturbations using VLF/LF transmitter signal associated with 2024 M7.5 Noto Peninsula earthquake in Japan

• DOI: 10.5194/egusphere-egu25-20397
• Publication Date: 2025-03-15T05:58:15Z
• Authors: Yasuhide Hobara; Alexander Shvets; Masashi Hayakawa
• Keywords: Peninsula; SIGNAL (programming language)

We report on the lower ionospheric anomalies observed around occurrence time of Noto Peninsula Earthquake (M7.5) January 1, 2024. A case study was conducted based continuous series data electric field amplitude acquired by VLF/LF-transmitter signal-receiving network operated University Electro-Communications in Japan. used nighttime fluctuation method to analyze and derived daily changes (1) trend (the average fluctuations) (2) dispersion variance fluctuations). As a result, decrease 4 8 transmission-reception paths 6 9 days before earthquake. An increase also conjunction with trend. These characteristics indicate short-term ionosphere anomaly earthquakes. For 2 close epicenter, remarkable one day This shows imminent precursor earthquake that contains clear oscillations period 30 – 240 minutes, implying LAI coupling due AGW. The simultaneous propagation indicates spatial extent preparation zone.