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Seismo- Electromagnetics

Atmospheric anomalies observed during earthquake occurrences

H. Fujiwara *, M. Kamogawa * et al. (* Co-first authors)

Appearance of anomalies in the atmosphere before earthquakes (EQs) has been verified, through observation of anomalous transmission of VHF electromagnetic (EM) waves beyond line-of-sight. Anomalous increase of the received intensity for a few minutes - several hours on a day was identified by the previous 15-day running median and its inter-quartile range. The cross-correlation between the EQ occurrences and the anomalies shows that the appearance of anomalies was significantly enhanced within 5 days before M≥4.8 EQs. The one-day average number of the anomaly appearance within 5 days was found 2.4 times larger than that of other days. Through the polarization measurement of the received EM waves, the anomalies were found to occur in the atmosphere.

Fujiwara*, and Kamogawa* et al., Atmospheric anomalies observed during earthquake occurrences, Geophys. Res. Lett., Vol. 31, L17110, doi:10.1029/2004GL019865, 2004. * Co-first authors

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