So Nobel blew up 1/3rd of Australia and survived standing in the center.
I thought this would likely get relevant for the verse in the future, so let's calculate that.
Area of Australia is 7692024 km^2.
1/3rd of that is 2564008 km^2.
So the explosion radius has to be 903.4097047598774 km
So using nuke formula:
((903.4097047598774/0.28)^3)/1000 = 33587691.9024101886523177 megatons of TNT = 3.3587691902410189e13 tons of tnt
Divide through 2, 'cause anti-matter explosion instead of nuclear and we get 1.6793845951205094e13 tons of tnt.
Country level. Nice.
Tesla might give even better results, though I am not sure if he tanked his own attack. Still, might calc him tomorrow.