Figure S2. C(T) calculation for the day of the Tohoku-Oki earthquake. (a) Snap shot of training (green) and prediction (red) based on the observed VTEC (black dots) at station 0214 for T = 5:20 UT (vertical gray line) on March 11, 2011 (DOY70). The time of the mainshock is shown with vertical black line. The polarities of the VTEC curvature are shown with broken lines. (b) Calculated C(T) using the 31 stations with the central station 0214.