jamesdevice
"looks to me like an explosion in or around that snaller grey roofed building just left of centre - just below the blue building mentioned by 500N"
I think you might be correct, the scorch / burn marks are darker here and typical of what you could get.
If it was rocket fuel for a Missile a la chemical, agree, re no crater.
From my experience, even small explosions of TNT, C4, AMFO detonated on the ground leave small craters unless tamped, which least me to the next point.
The blast radius / shock wave would be large enough and powerful enough to knock buildings around (and obviously nearly flatten those close by),
especially if there was nothing to contain it, slow it down, direct it upwards etc etc and there doesn't seem to be anything to do that.
Just my HO.
Here is a good normal and slow motion video of the Rocket Fuel fire and explosion in the US showing very good shock waves. I don't think the Iran one was nearly as big but the shock wave would have been the same.