how about some math? how much does each floor weigh? then do the math for me at 10%, 20%, 50%. (I'm asking you to do it because I cant stand doing math)answer to this question is "no", how much of the mass of the building do you think had been pulverised into dust or ejected away from the perpendicular by the time the collapse wave reached the last ten floors? 15%? 30%? 50%? This would be important in modelling the collapses, of course.