Introduction[]
This island is destroyed by a nuclear stockpile at the end of Ebirah, Horror of the Deep (1966)
Here are scans of the island and its mountains
https://i.imgur.com/2W2OuLc.png
https://i.imgur.com/rBMKxYM.png
https://i.imgur.com/s2N5e7s.png
Calculation[]
https://i.imgur.com/d65Ckrt.png
3000m mountain assumption
https://i.imgur.com/WaIbhVZ.png
106 px = 3000m
869 px = 24594m
https://i.imgur.com/IduMTg6.png
650 px = 24594m
28 px = 1059.4m
V = pi*r^2*h
pi*12297^2*1059.4
503278279337*1000000*8
4.0262262e+18e
962.29 Megatons
Now for the radius of one of the mountains
186 px = 6642.85m
pi*r^2*h/3
pi*6642.85^2*3000/3
138630491976*1000000*8
1.1090439e+18e
265.07 Megatons
Functions as a durability cieling for anyone comparable to Godzilla
1227.36 Megatons