Fig. 6From: Comparison of volcanic explosions in Japan using impulsive ionospheric disturbancesFrequency (~ 12.8 mHz) and period (~ 1.3 min) of TEC oscillations by explosive volcanic eruptions (vertical dashed line) drawn over the figure by Blanc (1985) showing the attenuation of airwaves in the Earth’s atmosphere. The frequency 12.8 mHz corresponds to the higher end of the atmospheric bandpass filterBack to article page