Calc Skyrim - Arch-Curate Vrythur destroys the Chantry of Auriel

4:40

Arch-Curate Vrythur destroys the Chantry of Auriel in a huge explosion. I've been meaning to do this for ages, but couldn't find a good way to scale. Thankfully, my friend supplied good scans to scale with, so let's get to it!
There seem to be 12 pillars there for reference. A quick search reveals that the average height of a man is 175cm (1.75m).
63 pixels = 1.75m
1 pixel = 1.75m/63 = 0.0277777778m
0.0277777778m X 135 = 3.75m
0.0277777778m X 116 = 3.22222222m
0.0277777778m X 24 = 0.666666667m
0.0277777778m X 72 = 2m
126 pixels = 3.75m
1 pixel = 3.75m/126 = 0.0297619048m
0.0297619048m X 378 = 11.25m
0.0297619048m X 41 = 1.2202381m
0.0297619048m X 211 = 6.27976191m
0.0297619048m X 197 = 5.86309525m
29 pixels = 3.22222222m
1 pixel = 3.22222222m/29 = 0.111111111m
0.111111111m X 5 = 0.555555555m
0.111111111m X 9 = 0.999999999m
0.111111111m X 153 = 17m
0.111111111m X 21 = 2.33333333m
0.111111111m X 254 = 28.2222222m

Volume of the main room as a rectangular prism, of the roof bit as half a cylinder and the pillars as rectangles.

H = 11.25 - 3.75
= 7.5m

V = 7.5 X 17 X 28.2222222
= 3598.33333m^3

28.2222222 - (0.666666667 X 2) = 26.8888889m
17 - (0.666666667 X 2) = 15.6666667m
7.5 - 0.666666667 = 6.83333333m

V = 26.8888889 X 15.6666667 X 6.83333333
= 2878.60494m^3

V = 3598.33333 - 2878.60494
= 719.72839m^3

V = 28.2222222 X 2 X 2
= 112.888889 X 2
= 225.777778m^3

V = 28.2222222 X 0.666666667 X 0.666666667
= 12.5432099 X 2
= 25.0864198m^3

V = 225.777778 - 25.0864198
= 200.691358m^3

V = 0.555555555 X 0.999999999 X 6.83333333
= 3.79629629 X 12
= 45.5555555m^3

V = 2.33333333 X 0.999999999 X 6.83333333
= 15.9444444 X 12
= 191.333333m^3

28.2222222m - 6.27976191m = 21.9424603m

V = πr^2h
= π X 5.86309525^2 X 21.9424603
= 2369.67667m^3

21.9424603 - (0.666666667 X 2) = 20.609127m
5.86309525 - (0.666666667 X 2) = 4.52976192m

V = πr^2h
= π X 4.52976192^2 X 20.609127
= 1328.49591

V = 2369.67667 - 1328.49591
= 1041.18076/2
= 520.59038m^3

Now to add all of that up.

V = 719.72839 + 200.691358 + 45.5555555 + 191.333333 + 520.59038
= 1677.89902m^3

Finally for our energy. It looks pretty violent, so obviously we'll be going with violent fragmentation, which is 69000000 joules per m^3.

E = 1677.89902 X 69000000
= 115775032380 joules
= 27.6708968403442 tons of TNT

Final Results
Arch-Curate Vyrthur destroys the Chantry of Auri-El = 27.671 tons of TNT