Using this Scale for the Giant GT Robot's leg
Scaling 1:
Leg = 9.4m = 194.3
Whole Body = 315px = 15.3
Scaling 2:
GT Robo = 15.3m = 7px
Crater Length = 581px = 1269.9m
Crater Width = 67px = 190.2m
Update:[]
Crater Depth = No less than 20m
I'll treat this as a half ellipsoid:
V=(2/3)πabc
a=1269.9
b=190.2
c=20
10117393.5834m
Low End:
Violent Fragmentation: 69cc/j
E = 6.9810016e14 J = 166.84994 KT of Tnt
High End:
Pulverization: 214.35cc/j
E = 2.1686633e15 J = 518.32297 KT of Tnt
Estimated somewhere roughly around: 342.586455 KT of Tnt