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Background Attack Aftermath Evidence Misinformation Analysis Memorial

Collapse Features

Characteristics of the Twin Towers' Destruction and What They Show

The total destructions of the two towers were almost identical. The most apparent difference is that the top of the South Tower tipped for a few seconds before falling, whereas the top of the North Tower telescoped straight down from the start. Here are some of the principal characteristics of the destructions, based on study of the surviving evidence.

  • The cores were obliterated. There is no gravity collapse scenario that can account for the complete leveling of the massive columns of the towers' cores.
  • The perimeter walls were shredded. No gravity collapse scenario can account for the ripping apart of the three-column by three-floor prefabricated column and spandrel plate units along their welds.
  • Nearly all the concrete was pulverized in the air, so finely that it blanketed parts of Lower Manhattan with inches of dust. In a gravity collapse, there would not have been enough energy to pulverize the concrete until it hit the ground, if then.
  • The towers exploded into immense clouds of dust, which were several times the original volumes of the buildings by the time their disintegration reached the ground.
  • Parts of the towers were thrown 500 feet laterally. The downward forces of a gravity collapse cannot account for the energetic lateral ejection of pieces.
  • Explosive events were visible before many floors had collapsed. Since overpressures are the only possible explanations for the explosive dust plumes emerging from the buildings, the top would have to be falling to produce them in a gravity collapse. But in the South Tower collapse, energetic dust ejections are first seen while the top is only slightly tipping, not falling.
  • The towers' tops mushroomed into thick dust clouds much larger than the original volumes of the buildings. Without the addition of large sources of pressure beyond the collapse itself, the falling building and its debris should have occupied about the same volume as the intact building.
  • Explosive ejections of dust, known as squibs, occurred well below the mushrooming region in both of the tower collapses. A gravitational collapse explanation would account for these as dust from floors pancaking well down into the tower's intact region. But if the floors -- the only major non-steel building component -- were falling well below the mushrooming cloud above, what was the source of the dense powder in the cloud?
  • The halting of rotation of the South Tower's top as it began its fall can only be explained by its breakup.
  • The curves of the perimeter wall edges of the South Tower about 2 seconds into its "collapse" show that many stories above the crash zone have been shattered.
  • The tops fell at near the rate of free fall. The rates of fall indicate that nearly all resistance to the downward acceleration of the tops had been eliminated ahead of them. The forms of resistance, had the collapses been gravity-driven, would include: the destruction of the structural integrity of each story; the pulverization of the concrete in the floor slabs of each story, and other non-metallic objects; and the acceleration of the remains of each story encountered either outward or downward. There would have to be enough energy to overcome all of these forms of resistance and do it rapidly enough to keep up with the near free-fall acceleration of the top.


page last modified: 2008-05-17