Fig. 4From: Comparison of volcanic explosions in Japan using impulsive ionospheric disturbancesFit of the model function (shown as a red curve in the middle) to one of the STEC curves in Fig. 3 for each eruption. The period of the TEC fluctuation (Heki 2006) is fixed to 1.3 min, and adjusted the amplitudes and time lags to minimize the difference between the model function and the observed TECBack to article page