The attacks on the World Trade Center were the equivalent of a 2.0 magnitude earthquake, experts said.
"This is the most significant collapse of a building in history," Art Lerner-Lam, Associate Director for geology and geophysics at Colombia University's Lamont-Doherty Observatory, told CNN.
"But the (seismic) impact is relatively mild."
While the Richter Scale specifically applies to earthquakes, Lerner-Lam said Lamont-Doherty seismologists calculated that both planes' impacts into the two World Trade Center towers would have registered a magnitude of 0.8.
The eventual collapses, he said, would have measured a magnitude of 2.0.
No information was available what the seismic repurcussions would be if two nearby building affected by flying debris and resulting fires -- a 54-story structure called One Liberty Plaza or the trade center complex's 9-story building 5 -- collapsed
"If just the airplane impact had occurred, and there wasn't any fire, I don't think the buildings would have collapsed," said John Filson of the United States Geological Survey. "The fire here was the terrible thing that weakened the structure, weakened the floor where this was hit."
Aaron Swirsky said "nobody could foresee something like" what unfolded Tuesday when he and 13 other architects designed the World Trade Center in the early 1970s – Albawaba.com
© 2001 Al Bawaba (www.albawaba.com)
