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Why Fact-check? Why preserve a visual record?

The Website Written as a Book
1: Science and Subjective Viewpoints
2: Toward Accurate Collapse Histories
....2.1: Progressive Floor Collapses in the WTC Towers
....2.2: General Global Characteristics of Collapses
....2.3: Mathematical Basis of ROOSD Propagation
....2.4: WTC1 Accurate Collapse History
....2.5: WTC2 Accurate Collapse History
....2.6: WTC7 Accurate Collapse History
3: WTC Collapse Misrepresentations
....3.1: Purpose of the NIST Reports
....3.2: NIST WTC1 Misrepresentations
....3.3: NIST WTC7 Misrepresentations
....3.4: NIST WTC2 Misrepresentations
....3.5: Reviewing the Purpose of NIST and FEMA Reports
....3.6: Bazant Misrepresentation of Collapse Progressions
....3.7: Block Misrepresentations of Collapse Progressions
....3.8: AE911T Misrepresentations of the Collapses
4: Scientific Institutions Can Be Unaware of Contradiction
5: Reassessing the Question of Demolition
....5.1: The Case of WTC1
....5.2: The Case of WTC2
....5.3: The Case of WTC7
6: WTC Collapse Records Studied as Meme Replication
....6.1: Meme Replication in Technical Literature
....6.2: Meme Replication in Mass Media
....6.3: Meme Replication in Popular Culture
....6.4: John Q Public and the WTC Collapse Records

WTC Twin Towers Collapse Dynamics

Official, Legal Attempts to Explain Collapses

Academic Attempts to Explain Collapses Reviewed

On the Limits of Science and Technology

WTC Video Record

WTC Photographic Record
WTC1 Attack to Collapse
WTC2 Attack to Collapse
Fire Progression, WTC1 North Face
Fire Progression, WTC1 South Face
Fire Progression, WTC1 East Face
Fire Progression, WTC1 West Face
Fire Progression, WTC2 North Face
Fire Progression, WTC2 South Face
Fire Progression, WTC2 East Face
Fire Progression, WTC2 West Face
Debris: WTC1 Around Footprint
Debris: WTC2 Around Footprint
Debris: From WTC1 Westward
Debris: From WTC1 Northward
Debris: From WTC2 Eastward
Debris: From WTC2 Southward
Debris: Plaza Area, Northeast Complex
Debris: Hilton Hotel, Southwest Complex
Debris: General, Unidentified Locations
Damage to Surrounding Buildings
Perimeter Column Photo Record
Perimeter Columns: Types of Damage
Core Box Columns: Types of Damage
Complete Photo Archive
Other Major 9-11 Photo Archives
The 911Dataset Project

WTC Structural Information

Log In


Remember Me

Online Misrepresentations of the WTC Collapses

Forum, Blog Representations of the WTC Collapses

The Book Tested Through Experiments

Miscellaneous Notes, Resources
FAQ for Miscellaneous Notes
History Commons 9/11 Timeline
The 911Dataset Project
Skyscraper Safety Campaign
First and Largest 9/11 Conspiracy Theory
Key Words in Book and Website
Trapped Within a Narrowed False Choice
Vulnerability and Requestioning
On Memes and Memetics
Obedience, Conformity and Mental Structure
Denial, Avoidance (Taboo) and Mental Structure
Taboos Against Reviewing the Collapse Events
Extreme Situations and Mental Structure
Suggestibility, Hypnosis and Mental Structure
Awareness and Behavior
Magical, Religious, Scientific Cause-Effect Relations
The Extreme Limits of Mental Dysfunction
Orwell's "Crimestop", "Doublethink", "Blackwhite"
William James, Max Born: Science as Philosophy
Plato on Self Reflection and Mental Structure
Rewriting History, part 1
Rewriting History, part 2
On Smart Idiots

New Ideas in Education

Reassessing the Question of Demolition: WTC7

Reassessing the Question of Demolition: WTC7



The collective visual record of the WTC7 collapse is examined directly and independently of all other sources, groups or individuals. The movement of the structure during the initial column failure sequence is mapped and traced back to the earliest point of detectable movement from multiple angles. Features of the initial failure sequence can be understood as a rapid succession of 7 identifiable events occurring in the following order:

1) Movement Detected from 2 Minutes before Collapse
2) Increase of rocking 6 seconds before visible collapse
3) Ejections and overpressurizations
4) Collapse of the East Penthouse
5) Collective core failure
6) Perimeter response
7) Acceleration downward

Collapse Progression and Rubble Distribution

1) Movement Detected from 2 Minutes before Collapse

The earliest detectable movement leading into the visible collapse process was never recognized in the NIST report. There is nothing within the NIST reports or simulations that can explain this type of movement.

The trace process of the northwest corner using sub-pixel tracing (syntheyes) demonstrated:

This camera angle is called the "camera #3 viewpoint" in the NIST report.

The corner started to rock back and forth at about 90 seconds before visible collapse began.

The blue line indicates the moment when visible collapse first begins (when the east penthouse starts to fall).

high resolution here

high resolution here

The early rocking has never been explained. It has not even been detected outside of the measurements reproduced here.

There most probably never will be any official attempt to explain the earliest rocking motion or to consider how this affects the NIST simulations and explanation of the collapse. This is because it will probably never be acknowledged to exist.

According to the NIST, the earliest motion began with rocking of the northwest corner of the building about 6 seconds before the first visible signs of collapse. This rocking is discussed next.

2) Increase of rocking 6 seconds before visible collapse

About 6 seconds before the collapse first becomes visible the northwest corner starts to rock more intensely. This movement was detected by the NIST and they consider it to be the earliest detectable motion. The first visible movement was the collapse of the east penthouse and is indicated in the graph. Once the east penthouse begins to fall, the rocking becomes even more intense until the whole penthouse starts to fall collectively about 5 seconds later.

Building Rocks Horizontally Before Collapse

The NIST measurements are posted over an independent measurement of the same movement. Both sets of measurements match well over this range.

Jet Flames from 13th Floor Just Before Collapse


4) Collapse of the East Penthouse

Facade behavior examined using color enhancement during east penthouse collapse:

E Penthouse Free-falls Through Building
E Penthouse Collapse and Suction

5) Collective core failure

The first phase of core collapse is the east penthouse shown at 0:06 in this video:

The second phase of collapse consists of the rest of the collective core which follows about 5 seconds later.

6) Perimeter response

Perimeter Deforming During Early Motion

This is a model that captures the general relationship between the core falling and the perimeter responding

camera 3


This type of core motion is one in which the collapse occurs in 3 stages, as described at this link.


Coupled reaction between core and perimeter

So how is it possible for the perimeter to drop faster than free fall?

Drop curves for the core, northwest corner and northeast corner compared

The core drops first, followed by the east corner and then the west corner.

Of course, the center of mass of the entire system cannot exceed gravitational acceleration, but the perimeter can.

Core and perimeter were still connected through the floor system. Once the core dropped at gravitational acceleration the core-floor-perimeter could have acted like a spring system. First, the core pulled the perimeter inwards. Secondly, the perimeter failed at a very low elevation and was then pulled downwards by the "floor-springs". The falling core slows down at that same time until the entire system fell as one unit.

Drop rates and velocities of core and perimeter compared

4 points are measured; 3 of the points track east, west, and center of the penthouse and one point tracks the west corner of the building. Downward displacements and corresponding velocities are compared to freefall movement.

The west side of the penthouse begins to follow a freefall trajectory but the acceleration decreases just as the acceleration of the west corner of the building takes off. It is then the west corner that follows or exceeds a freefall trajectory.

It appears that the core was slowed down by the perimeter as the perimeter began a sharp acceleration downward. The core appears to have strained the floors, took down the perimeter, and catapulted the outer shell downward. After this, it appears the whole interconnected unit fell together.

Displacement, velocity and acceleration profiles of the northwest corner from the Dan Rather viewpoint:

Syntheyes tracing the northwest corner Dan Rather viewpoint shown here.

The downward displacement is shown next to the NIST measurements using the camera 3 viewpoint. As described in part 3.3, the NIST made a number of mistakes when measuring downward displacement, velocity and acceleration of a point on the building. The mistakes made are too numerous to reproduce here.

In short, they measured a point on the roofline using the camera 3 viewpoint, but they didn't take account of the perimeter flexure discussed as event #6 and didn't seem to notice that the penthouse movement and perimeter movement cannot be distinguished for their first 4 data points. This is explained in detail in section 2.4.

high resolution here

7) Acceleration downward


The NIST acceleration profile is graphed and compared to the downward acceleration of the northwest corner measured from the Dan Rather viewpoint.

high resolution here

Multiple methods of extracting downward acceleration from displacement data yield the same trends:

Acceleration of the northwest corner seems to exceed gravitational acceleration for a short period. This may be able to be explained through the perimeter coupling to the core. In this sense the core is literally pulling the perimeter down.

Recall the drop data of multiple points along the roofline presented earlier.

One can see both core (screen wall) and northwest corner movement relative to a free fall trajectory.


The Demolition of 1515 Flagler Dr...

The downward displacement of this demolition is compared to the downward displacement of the northwest corner of WTC7.

larger version here

A quick look at derived acceleration suggests very near to freefall, if indeed it is not actually reached...

larger version here

NE Corner Folds In and Over Building
Building Folds Into Compact Rubble Pile

Also of interest are two different comments made by the owner of WTC7, Larry Silverstein, about the collapse and reconstruction of the building. Within the first clip he states that plans for a new building were beginning to be prepared in April, 2000, over 1 year before the then existing WTC7 actually collapsed:

This next clip highlights comments made by people evacuating the area before the collapse of WTC7:

WTC7 (notes)

FEMA Photographer Sonnenfeld Testimony
Fire Much Less Intense Than Other High-Rises

----------BEFORE COLLAPSE-----------
Damage to the South Side, Internal and External
Jennings Testimony of Explosions
Premature Reports of WTC7 Collapse
Evacuation Personel Predict Collapse

On to Part 6: WTC Collapse Records Studied as Meme Replication

Created on 09/19/2012 03:37 PM by admin
Updated on 03/27/2016 09:33 AM by admin
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