[T-Bone Texan]

"...The Facility is 45 feet underground and certified to withstand a 20K ton nuclear blast..."

A blast where, exactly? Directly overhead?

My house is certified to withstand a 20k nuclear blast too, as long as that blast occurs in Iran.

[ctdonath2]

“Directly overhead?”

Probably, so long as it’s not actually detonated on the surface. 45 feet deep is pretty far, and any appreciable altitude will mitigate crater depth. 20kT is about equal to the Hiroshima blast, which did leave buildings standing near ground zero.