National Institute of Standards and Technology (NIST) Federal Building and Fire Safety Investigation of the World Trade Center Disaster

Editors Note: An example of an answer to a FAQ. NIST is clearly wrong about the seismic data being a determination of the collpase duration.

6. How could the WTC towers collapse in only 11 seconds (WTC 1) and 9 seconds (WTC 2)—speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?

NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A).

Editors Comment: NIST says they determined the duration of the collapse of based on seismic readings. How did they determine when the ground began to shake, and how did they determine what started the ground shaking? This NIST statement is false on it's face. The duration of the collpase cannot be determined based on the seismic data.