Hodocrone reporting dTEC over Italy from 16,800 km to 18,500 km from the Hunga volcano as function of time since the eruption (13–19 h). The solid and dotted black lines represent the theoretical time of arrival calculated by considering waves propagating at the velocity reported in the legend northward and southward, respectively. Dashed and dot-dashed black lines represent the corresponding error band of ±5%.