how big was Halifax?

Rrright … talking out of my backside here. 😮

Hm. That would put Helgoland in front I guess – 6800 tonnes of bombs and ammo.
A lot of these giant explosions are not really a single explosion, but more like serial.
They say Helgoland was big enough to show up like an earthquake on seismographs as far as the Schwarzwald.