Verse: Avatar
In my marathon of the excellent Avatar series, I noticed this flashback feat.
The Feat[]
The Calc[]
For the sake of being as conservative as possible, I'll use the height of the smallest volcanoes on Earth. That would be the cinder cone volcanoes, which tend to be 91m tall and resemble the ones shown in the video.
I also realized halfway through the calc that calc'ing only one of the eruptions and multiplying would be way easier, so:

- Volcano = 55px = 91m
- Partial height of the lava burst = 292px
- Diameter of the lava = 39px = 64.5272727271m

- Additional height = 440px
- Total height of the lava formation = 732px = 1211.12727273m
- Cylindrical volume = 11881945.0795^3 (already multiplied by 3)
- Mass = 11881945.0795*3100kg/m^3 (density of lava) = 36834029746.5kg
Watchframebyframe dictates that they start erupting at frame 485 and finally stop at 500, or about 15 frames. Assuming 25fps, that is 0.59999999999 seconds, or 2018.54533 m / s m/s for the speed.
- KE = 0.5*36834029746.5*2018.54533^2 = 7.5040592e+16 joules, or 17.935131931166349517 megatons (City level)
And this is assuming the volcanos only reached that height once the screen went up to show the full height of the lava, which is implied harshly not to be case. If you assume otherwise, it's 10 frames, or about 0.4 seconds. That'd yield 1.6884133e+17 joules, or 40.354046367112808014 megatons.
Either way, City level for all Avatars without energybending, although I believe this should only scale to Adult Aang, not his child self. He has his own Town level feats to scale from in the battle against Ozai.