Dude. city. han river. vaporized.
Han river is 1km wide or so, at most ~150 meters in the thicker parts. this doesn't seem to thick so i'll just use a kilometer.
crater has a flat bottom so it's a cylinder.
670px wide so 335px in radius
river is 117px wide so 1000/117=8.547 m/px
8.547*335=2863.245m or 286324.5 cm
best depth shot that doesn't have a diagonal line is 23px so 23*8.547=196.581 meters or 19658.1 centimeters.
using omnicalculator i get 5063005913821072.05 cm^3
Low-end: Pulverization in case the translation is wrong for some reason
5063005913821072.05*69=3.4934741e+17 joules = 83496034.894837 tons of TNT or 83.496 megatons - 7-B, City level+
5063005913821072.05*214=1.0834833e+18 joules = 258958723.70937 tons of TNT or 258.958 megatons - 7-A, Mountain level
High-end: Vaporisation (25700 j/cc)
5063005913821072.05*25700=1.3011925e+20 joules or 31,099,247,131.931 tons of TNT - 6-C, Island level