The 9/11 Forum

For the WTC 1 north and west faces, there are clear horizontal lines along which the building was originally seen to fail

The following ppt presentation is an excellent way to see the original ejections and failure points along these 2 faces.

http://www.cool-places.0catch.com/docs/Wtc1SeriesNW.ppt

5MB downloadable

We can see the entire west face give along a horizontal line along the 97th floor. We also see the north face give along the same line on the same floor, but the original airplane opening a bit lower also forms the line along which the north face originally gives.

I'll supply more clips that show the same thing in an upcoming post.


Now please look at the following photos of the west and north faces.






You can see a blackened line form across the west face (second photo) shortly after the aircraft impact at the same location we later see it fail.

In the first photo you can see the same blackened line wrap around the NW corner and continue across the north face at the exact same elevation. It is perfectly horizontal. You can also see the beginning of the 94th floor blackened line. It will later wrap itself around the corner and continue across the entire length of the west face.


Since there is clearly a blackened line at the same plane as we will later witness the exterior give it is obviously of interest in the study of the collapse initiation of WTC 1.

The evolution of the 97th floor blackened line and the one across floor 94 is rather fascinating.

The photo album linked below are the original NIST time-stamped photos used in chapter 8 1-3(?) dealing only with the west face and put in the proper order.

http://www.sharpprintinginc.com/911_1_west_sequenced/

The photos are labelled by time taken and the NIST report label. For example:

09-40_8-69.JPG means that the photo has a time-stamp of 9:40AM and is referred to as 8-69 in the NIST report.

Using this album you can see how these blackened lines which extend entirely across floors 97 and 94 evolve over time.

It would be hard to study the WTC 1 collapse initiation without noting the existence of these lines which were so distinct that they could be seen from very far away.

I'll take that as evidence that the smoke found an exit path all along those floors; lack of internal walls plus broken glass.

Please note that by 9:10 a single horizontal blackened line (appears glowing red in this photo) has formed across the entire 97th floor, west face from corner to corner.



This is exactly where we see the west perimeter give way more than 1 hour later so that fire must have done more than leave smoke marks.

After this time using the photo album given in the OP you can see that the 97th floor fire dies down and never again reignites.

By 9:14 we don't see any more large fires along floor 97, west face (except the right corner). The glowing red has disappeared leaving a clear black line.

The 97th floor fire never again is noticably visible.




Hypothesis: All WTC 1 collapse initiation videos in which the west side is visible show that the interconnected west perimeter wall above this 97th floor blackened line begins to move downward as a single interconnected body.

The interconnected perimeter wall below the 97th floor blackened line is seen not to move to the point at which they are obscured by smoke and dust ejections.

Hence this blackened line acts as a "severing plane", effectively detaching the perimeter columns above it from the ones below it allowing the ones above to move downward during collapse initiation.

Major_Tom --- I'm impressed.

Have you checked the north face video for the 97th floor?

???

I made a paper airplane out of the program early in the performance.

Is the play over?

What did it mean?

Max Photon wrote:???

I made a paper airplane out of the program early in the performance.

Is the play over?

What did it mean?

What on Earth?

This is an awesome topic, Major Tom!

I've notice these odd lines for a while, but could not wrap my head around how the planes could have caused them. There is no doubt the initiation happens exactly at this point.

If the core structure was compromised down low, creating a massive "pulling down" of the floors above, the perimeter columns below the "cut", would bow inwards, allowing the top to easily deform and break the welded/bolted ends. However, in your PowerPoint, the perimeter columns below appear intact up until the smoke/dust obscures them. This too, is strange.

Are there photos that show these lines on the South and East faces?

Could you post this on the STJ fora, please?

Ian wrote:

Max Photon wrote:???

I made a paper airplane out of the program early in the performance.

Is the play over?

What did it mean?

What on Earth?

I couldn't tell if David is being serious or playfully facetious.

(He can be subtle.)

Max

AFAIK there are no videos showing details of the south or east faces during the last 20 seconds (minutes?) before the collapse of WTC 1.

But by police helicopter voice and the earlier police footage we know that while the south wall bent in towards the east side, it was near the southwest corner which buckled first; this instability quickly propagated along the south, west and east walls tipping the top part to the south; in about 0.8--1 seconds, the hinge along the north wall broke.

NIST makes a fairly big thing in NCSTAR1--6 or NCSTAR 1--6D about no tilting to the east observed. I infer that means none to the west observed either.

However, it is my view that the south and east walls largely fell apart, while the west and north walls feel over in mauch larger units.

Thanks, David.

But by police helicopter voice and the earlier police footage we know that while the south wall bent in towards the east side, it was near the southwest corner which buckled first; this instability quickly propagated along the south, west and east walls tipping the top part to the south; in about 0.8--1 seconds, the hinge along the north wall broke.

I've heard about this hinge many times but I have seen no evidence for it. Here's why I question it:

We know the South Tower clearly hinged as show in the collection of photos below. We can even locate the hinge. Note how the first smoke ejections look just after collapse initiation.



Pretty simple and just what we would expect.

Now using the ppt photo sequence linked in the OP we see quite a different ejection pattern for the North Tower just after collapse initiation. One of these photos is shown below.



This is the NW corner and the building is said to hinge to the south along the north wall (or anywhere one wishes to make the argument).

The ppt photos show a very even ejection line along the west face at the 97th floor. It is not stronger near the south corner and it is clearly as strong at the NW corner as it is along it's entire length.

This is contrary to what we see in the South Tower and contrary to common sense if we assume a hinge exists.

Also note that we see powerful ejections along the entire north face at the same altitude at the exact same time. No delay.

We must conclude that the NW corner failed during the earliest moments of collapse initiation and there is a simultaneous collapse of the 97th floor along the entire north and west perimeters.

In the ppt photo series we are looking at the north and west faces and we are not seeing any visible hinging as we did in the South Tower.


The only decent arguments I have ever seen for hinging of the NT along the north face was given by "Mangoose" in the JREF forum. He only used antenna tilt to make his point. Initial ejections are clearly telling us something different.

Ian asks:

Could you post this on the STJ fora, please?

I can't because Victronix kicked me out of that forum for for daring to ask difficult questions to it's star, Steven Jones.

It is also hard to understand why the ejections in the beginning occur at all.



They are quite symmetrical althought the top section tilts. I don't think it is easy to explain it.

Major_Tom --- Look at the video of WTC 1 which is shot directly from the north; the Sauet(?) video. Go to frame 917 +- several depending upon the version you have. You will see, I believe, the north wall beginning to collapse over about five floors from 93 up. Which ever frame it might be, detrmine the titlt angle of the antenna tower. If around 8 degrees of arc, then the other three wall sides have already failed by then and the hinge was along the north wall.

If you take the video shot from the west and stop frame it, you might be able to detect the instability racing from south to north in less than 3/4 of a second.

I am absolutely NG at photo-interpretation, so I have to rely on the reports of others.

I'll return to the hinge shortly.

Two videos from which to study the north face collapse initiaton:

BBC
http://www.youtube.com/watch?v=Xo7t3XQ2 ... re=related

Sauret
http://www.youtube.com/watch?v=Ujw1FPq0pNM

On edit: This third clip are some Sauret close-ups
http://www.youtube.com/watch?v=NoTcQxiz ... re=related

The collapse initiation happened over a few stories because of the airplane hole through the center of the building.

Notice how both the NW and NE corners give at the same moment in time.

The NW corner gives at floor 97. The NE corner gives at 96 or 97. The center portion of the north face gives lower, along the airplane hole.

Go to frame 917 +- several depending upon the version you have. You will see, I believe, the north wall beginning to collapse over about five floors from 93 up.

Both corners give at the same time at the same elevation. There is no noticable separation in time when looking frame by frame between the NE and NW corner failure.

A large 5 floor corner piece falls off the building from the NE corner shown below.



That large piece to the left seen leading the falling debris is from the NE corner, floors 92 to 97 or 94 to 98. It seemed to fall off the building pretty easily and doesn't seem to be considerably buckled

The reader will naturally ask how I know it came from floors 92 to 97 or 94 to 98.

If you view the BBC video frame by frame, forwards and backwards many times, you can see from where it comes.

Just as we looked at the strong horizontal burn line along the west face, floor 97 in this thread, I'll show similar burn lines along the north face (also floor 97, quite a queer line visible half way across Manhatten) and along floor 94 and 92 along the NE and NW corners.

It is apparently from between these lines that this large corner piece was "carved out".