So I don’t want to imply that the Beirut disaster didn’t result in any casualties, because that’s obviously not true. But I was also thinking about the asteroid that hit Chelyabinsk which resulted in a lot of broken windows but not a great deal of injuries.
In: Physics
It all comes down to the overpressure and local construction
When there’s an explosion, the shockwave that you see propagating outward is a sudden increase in pressure from the ambient, how big of an increase in pressure it is determines what damage it will do. Lots of research was done into what overpressure thresholds have what effect during the nuke testing in the 60s
Windows will shatter at just 1 psi of over pressure
Brick walls will break at 2 psi of over pressure, but fatalities from the blast are unlikely
Non concrete buildings will collapse at 4 psi of over pressure, fatalities will occur at this level from blast effects
Nukes target their blast altitude to give the largest 5 psi overpressure which takes out any non-reinforced buildings and produces widespread fatalities
The level at which windows shatter is actually really low, and since the Chelyabinsk meteor detonated sooo high up, there weren’t any parts of the city that experienced really high pressure unlike in Beirut where a couple blocks could be the difference between 1 psi with broken windows and 4 psi with collapsed buildings.
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