Building 7's Rubble Pile
Less than seven seconds after Building 7 began to implode,
all that was left of the steel skyscraper was a rubble pile.
The rubble pile is notable for several features:
* its location - It was centered around the vertical axis of the former building.
* its size - The pile from the 47-story building was less than four stories high.
* its tidiness - The pile was almost entirely within the footprint of the former building
What does the shape of the rubble pile indicate about the events leading to the collapse of building 7?
Consider the rubble piles produced by other collapses.
The only examples of total collapses of steel frame highrises
(excepting WTC 1, 2, and 7) involved either severe earthquakes
or controlled demolition.
Total collapses due to earthquakes are extremely rare. The rubble piles of the few documented cases had none of the above features. 1
Total collapses due to controlled demolition generally have all of the above features. In fact, to achieve such a small, consolidated rubble pile is one of the main objectives of a controlled demolition.