This is the most accurate set of data most of you have ever seen on the early movement of WTC1. If you look at the link I posted to The 9/11 Forum you will see many, many, many pages of interesting research, while on this forum an almost anti-intellectual, anti-research atmosphere if fostered and encouraged.
Drop curves can be used to map the correct early motion of WTC1. First we synchronize video clips of collapse initiation from multiple angles.
Then we try to locate the release moments of at least 4 key anchor points. I recommend:
1) SW corner fire
2) NW corner
3) NE corner
4) Antenna
Current data shows the placement of 4 key release events as:
SW corner release event at Sauret frame 208
NW corner release event at Sauret frame 222
NE corner release event at Sauret frame 208
Antenna black/white transition release event at between Sauret frame 208 and Sauret frame 215
I encourage all capable readers to locate these events as accurately as possible and share the results.
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An application of the data:
We can show that the first even row of ejections on the west face emerged before the release events of the core or west perimeter. It emerges before slab movement can explain it.
Argument: Visual inspection of the following gif of the initial west face ejections and the movement of the 104th floor fire shows that the ejections appear practically simultaneously with the release moment of the SW corner. The release moment of the SW corner is Sauret frame 208.
If these ejections have a natural cause, it must be due to floor slab movement which displaces, or "fans", air out the west face 98th floor windows. If the ejections appear in Sauret frame 208 before the release point of either the SW or NW corners, what type of floor slab movement could have caused the ejections?
Solution: Since the ejections line up with the core, we look for possible movement of the 99th floor OOS west slab or the core slab. The OOS west slab is attached to the west perimeter on one side and the 501 to 1001 core columns on the other side. We know the perimeter did not move before that time.
What about the core? The release point of the antenna is currently located between Sauret frames 208 and 215. According to current data the antenna slowly sagged about 2 ft in Sauret frame 208 but had not moved down with any significant velocity before this time.
According to current data, no floor slab that remained attached to the core or perimeter could have moved to create the forceful, even ejections witnessed in frame 208. Rapid downward movement of either floor slab could not have begun by this time.
The only other natural possibility: The 99th floor slab magically detached from the structure and fell between 0.5 and 0.9 seconds before Sauret frame 208. (A slab in free-fall will take just over 0.8 seconds to strike the one below).
One last possibility: The 98th floor experiences a high pressure event through the core around Sauret frame 200, just before the release event of the antenna. Core pressurization precedes core release by about 1/10th of a second!!
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A second application of the data:
Problem: The release events of the NW and SW corners differ by only 14 frames. This means that all 60+ columns along the west wall failed within a 0.25 second interval.
Also, all 4 release events listed above occur within a 14 frame, or 0.25 second interval.
Solution: It is impossible for a successive chain of events to occur within a 0.25 second interval. The west perimeter wall failure must be re-envisioned and remodeled as a single destructive mechanism of movement that propagates across the 207 ft facade basically instantaneously.
Best to forget about the NIST's claim that buckling moved from south to north over a tilt of 8 degrees. Almost no tilt angle is possible if all 4 release points are within a 0.25 second interval.