For all the horror, at least this happened at the quayside and half the explosive force radiated away almost harmlessly over the sea. That basically halved the actual destruction at the outset. If it had been in the middle of the city, there would have been twice the damage. This much is fairly obvious.

What isn’t quite so obvious is that roughly half the energy was also wasted upwards, and that a startlingly worse case would have been if the explosives had been slightly interred, coupling the blast more closely to the ground and enhancing amplitude of the p-waves and providing plenty of really substantial debris raining down after basically ‘earth-quaking’ the buildings.

Roughly combining the two 50% ‘wastages’ leaves you with about only one quarter of the energy was actually really channeled into destruction, which I’m going to be charitable and call a third. In ‘ideal’ conditions you might’ve had three times as much devastation, and that’s a pretty shocking thing to consider, given the actual carnage.

NOTE: I had appended these considerations in a more inchoate form to the tail-end of another comment, but I figured I’d make them an item of their own and tidy them up a bit. Apologies for the duplication.