Thick red curve: summation of all LT observed by TEXES over the 2012–2019 period. This curve is the same as the red curve in Fig. 13. Thick blue curve: summation of all SO₂ vmr distributions vs LT, using the same dataset. For each observation, the distribution of the SO₂ vmr as a function of local time is calculated as described in the text. The sum of all SO₂ vmrs has been divided by 400.0 ppbv; this number corresponds to a typical value of the SO₂ vmr within the plumes over the whole period (see last column of Table 2); this normalization allows us to show both curves on the same scale. Thin lines: results using the dataset without the 2019 runs (34 points).