The average radius is (288+98)/2=193 px
Lenght is 1112 px
Volume = 130179933,7142856 px^3
Raz is 392 px tall, we'll assume a height of 170 cm, so 1 px = 0,43367346938775510204081632653061 cm
Volume = 130179933,7142856*(0,43367346938775510204081632653061)^3 = 10617752,779492075487785701535925 cm^3
I'll use violent fragmentation because there are only small fragments visible during the explosion.
Value is 18,34 j/cc
E = 18,34*10617752,779492075487785701535925 = 194.729.586 J Small Building level