First: I have to admit that I was wrong about the toppling. The top 20 floors or so of the south tower ( the second one hit, but the first to collapse) did fall over as a unit. It got hit in the corner.
http://www.public-action.com/911/jmc...S/1538563t.jpg
I'm not sure how this affects my theory. So far, not much. In order for that to happen, the central load bearing tube structure had to snap. That's a lot of breaking.
http://www.civil.usyd.edu.au/latest/wtc_plan.jpg
As it falls over, the steel columns on the other side are stressed & pull the building in the direction of the topple. But Isaac Newton says "NO!". As the top falls to the south, it pushes the rest of the building to the north. Anybody who's ever topped a tree will vouch for this. Now I'm sure somebody (not me) could come up with loads of numbers on how these competing stresses are affecting each other. I'll simplify it. the building is bending & being forced to sway farther than it would under any stresses it was designed to handle. The steel exoskeleton has some flexibility but the concrete throughout the central load bearing core tube is shattering & being pulverized all the way to the footings on the bedrock because concrete can't hold up to shear.
My position is that it's shock that breaks everything loose. It was a shock wave through the air that took out the Murrah Bldg in OKC back in '95. From the street. Same with the Kobar (sp) towers in Saudi Arabia. Concrete shatters. When the south tower collapses, regardless of why, is sends a massive shockwave through the ground. If memory serves, the siesmic shock was recorded. The north tower was damaged at the base in the '93 bombing. I don't care how you fix it, it's still just a patch. It's not like you can just jack up the building & redo the footings like Norm & Tommy do to an old Victorian. The north tower came straight down, & so did WTC 7. The tremor is right at the surface & only needs to travel a couple hundred feet down. The depth of most earthquakes is measured in miles. I'm currently in Brawley CA. Check this out.
http://quake.wr.usgs.gov/recenteqs/Maps/116-33.htm
Just click on any little square to get the details. I know a little about liquifaction, just from the watching the furniture shift. Don't worry. You get used to it. The dogs never do though.
Off to bed. This is fun.
