Seismic event indicating explosion at WTC

[DGM]

Are you sure? Origin times are used also for earthquakes. Surely they must have precise clocks for that?

Why would they need to be precise from one agency to another? I'm talking actual clocks (and machines)set by humans. These are things if need be can be reconciled later (if need be).

 

[Anders Lindman]

Why would they need to be precise from one agency to another? I'm talking actual clocks (and machines)set by humans. These are things if need be can be reconciled later (if need be).

But if that is the case, which I'm not convinced of, but let's assume that's true, then they could have done the same kind of reconciliation for the seismic events happening on 9/11. There were several seismic stations measuring the events; PAL was only one of them:

http://img137.imageshack.us/img137/6961/seis4.gif

Edited by LashL: 

Replaced repetitive image with link. See Rule 6.

 

[DGM]

But if that is the case, which I'm not convinced of, but let's assume that's true, then they could have done the same kind of reconciliation for the seismic events happening on 9/11. There were several seismic stations measuring the events; PAL was only one of them:

[qimg]http://img137.imageshack.us/img137/6961/seis4.gif[/qimg]

Sure but, That's has nothing to do with what your asking. Your trying to reconcile seismic data to NIST and the 9/11 report. NIST I believe (well after the seismic data release) used several different sources to reconcile their time (including seismic)

 

[Anders Lindman]

Sure but, That's has nothing to do with what your asking. Your trying to reconcile seismic data to NIST and the 9/11 report. NIST I believe (well after the seismic data release) used several different sources to reconcile their time (including seismic)

But wouldn't they have had very accurate time measurement at the WTC when the second plane hit? They knew that the first plane had hit. One of the towers was on fire. They must have been calculating that another terrorist attack could happen at any moment, not expecting a second plane perhaps, but bombs going off in the towers and other terrorist events.

 

[BigAl]

"At 9:03:11, the hijacked United Airlines Flight 175 hit 2 WTC (the South Tower) from the south, crashing through the 77th to 85th floors" -- Section 9.2 SEPTEMBER 11,2001: http://govinfo.library.unt.edu/911/report/911Report_Ch9.htm

The Commission report says that time came from a NEADS audio tape.

Any attempt to compare times to the second between clocks that have not been calibrated in advance represents a mistake in your methodology.

 

[DGM]

But wouldn't they have had very accurate time measurement at the WTC when the second plane hit? They knew that the first plane had hit. One of the towers was on fire. They must have been calculating that another terrorist attack could happen at any moment, not expecting a second plane perhaps, but bombs going off in the towers and other terrorist events.

Why would they be doing that (hindsight much)? If you remember, it was originally thought it was a small plane that hit by accident.

 

[Oystein]

Thermite coming up:

http://www.youtube.com/watch?v=lv2ck2qsiGA

Or pouring down rather. Ignore the 'body fluid from the dead people' mentioned in the video. That's clearly NOT what it was. (sorry, maybe I should not joke about this tragic event)

I have seen a lot of incompetent and bad videos on 9/11.

But this one hits an all time low point of aptitude.
This truther not only tries tells a false story, he even manages to misunderstand and totally misrepresent his truther sources!

 

[Anders Lindman]

Now I found an inconsistency in the seismic records.

In the first picture the stated origin time for the second collapse is in well accordance with the calculations.

But in the second picture the stated origin time for the second impact differs with 18 seconds compared with the calculations!

 

[Oystein]

LDEO says: "Zero corresponds to computed origin time of 10:28:31 EDT". Origin time means the start of the event at the source, i.e. at WTC (I didn't know that when I wrote the original post but now I do). And the arrow in the diagram shows that they put the origin time at the very beginning of the signal. So the origin time is at the start of the collapse.

They are seismologists, and this is a seismogram.

"Event" means "seismic event".
It does not mean "criminal event" or "structural event".
The seismic event does not necessaily start with the collapse event. It is the start of some seismic waves rising out of bckground noise.

The planes crashed into the towers with a kinetic energy around 3*10⁹ Joules. Most of which was absorbed by the building within 0.2 seconds and gave rise to a small seismic event.

When the top part of the south tower started its descent, after 1 second it had dissipated a kinetic energy of about 1.4*10⁹ J. (Mass of top part was roughly 6*10⁷ kg, distance fallen at 60% of g was 6m after 1 second, meaning that 40% of the potential energy had been dissipated: 6m * 6*10⁷kg * 9,8m/s² * 40% = 1.4*10⁹J. However, this took 1 second, not 0.2s.

So you could expect the seismic signal 1 second after the start of collapse to be one order of magnitude below the plane impacts.



This is a very amateurish back-of-the-envelope. I can't say how the lateral momentum transfer of the plane crashes would fare compared to the vertical momentum transfer of the crash in terms of magnitude and velocity of the resulting seismic waves.

All I am trying to point out is: In the early stage of the collapse, you would not expect a pronounced seismic signal.

 

[triforcharity]

I have had the 17 seconds travel time confirmed, but I will not reveal the source since it was not some information I found on the Web.

You can admit that you pulled that nuggett out of your underwear. It's cool.

 

[Oystein]

If LDEO says that there were no bombs, then they cannot be trusted if there really were huge explosions in the basements of the towers. But then the seismic data from 9/11 might not be trustworthy either.

Yeah. If.

But if there really were no huge explosions in the basements of the towers, then they can be trusted, right?

Assuming the consequent.
That's not how it works, Anders. You can't throw out evidence simply because it does not confirm the conclusion you want to draw.

 

[Anders Lindman]

They are seismologists, and this is a seismogram.

"Event" means "seismic event".
It does not mean "criminal event" or "structural event".
The seismic event does not necessaily start with the collapse event. It is the start of some seismic waves rising out of bckground noise.

The planes crashed into the towers with a kinetic energy around 3*10⁹ Joules. Most of which was absorbed by the building within 0.2 seconds and gave rise to a small seismic event.

When the top part of the south tower started its descent, after 1 second it had dissipated a kinetic energy of about 1.4*10⁹ J. (Mass of top part was roughly 6*10⁷ kg, distance fallen at 60% of g was 6m after 1 second, meaning that 40% of the potential energy had been dissipated: 6m * 6*10⁷kg * 9,8m/s² * 40% = 1.4*10⁹J. However, this took 1 second, not 0.2s.

So you could expect the seismic signal 1 second after the start of collapse to be one order of magnitude below the plane impacts.



This is a very amateurish back-of-the-envelope. I can't say how the lateral momentum transfer of the plane crashes would fare compared to the vertical momentum transfer of the crash in terms of magnitude and velocity of the resulting seismic waves.

All I am trying to point out is: In the early stage of the collapse, you would not expect a pronounced seismic signal.

But is it enough to only look at the amount of energy released? The seismic signal from the collapse of WTC 7 was smaller than the signals from the plane impacts, yet it was thousands of tons of steel and concrete that smashed into the ground.

 

[DGM]

Now I found an inconsistency in the seismic records.

In the first picture the stated origin time for the second collapse is in well accordance with the calculations.

[qimg]http://img714.imageshack.us/img714/9197/seis.gif[/qimg]

But in the second picture the stated origin time for the second impact differs with 18 seconds compared with the calculations!

[qimg]http://img834.imageshack.us/img834/5210/seis5.png[/qimg]

So?

 

[triforcharity]

I haven't checked the timing of the seismic event for WTC 7. The magnitude of the seismic event for the collapse of WTC 7 however was tiny for being thousands of tons of steel and concrete smashing into the ground. The reason was because the collapse was a very slow event that did not produce any sharp seismic spikes. The WTC towers on the other hand did produce very sharp spikes because of in addition to the slow collapses there were huge explosions triggered in the basements prior to the collapses.

And yet, nobody reported the huge explosions, no seismic signatures of explosives, no audio evidence, nothing.

Cool!!

 

[triforcharity]

Sorry for the off topic reply, but I think it's important to show that this is not so far-fetched as it first might seem. Simply rig the explosions like this:

[qimg]http://img522.imageshack.us/img522/8371/sh2u.gif[/qimg]

When the explosives are triggered the upper part breaks off and flies out to the left (indicating the outside of the building) and the lower part bends inwards to the right (representing the inside of the building).

[qimg]http://img512.imageshack.us/img512/3033/id2x.gif[/qimg]

And yet, nobody saw people inside the towers, rigging up their office space with explosives and cutting the columns with Oxy-acetelyne torches, and none of the outer columns showed this cut after the collapse.

Cool! Keep going with your fantasy!!

 

[BigAl]

But is it enough to only look at the amount of energy released? The seismic signal from the collapse of WTC 7 was smaller than the signals from the plane impacts, yet it was thousands of tons of steel and concrete that smashed into the ground.

Without the math and physics to back up that assertion, you've pulled it out of your butt.

There were no demolition explosions at WTC.

 

[Oystein]

But is it enough to only look at the amount of energy released? The seismic signal from the collapse of WTC 7 was smaller than the signals from the plane impacts, yet it was thousands of tons of steel and concrete that smashed into the ground.

The planes had about, as I said, 3*10⁹J kinetic energy (+/- 13% or so, respectively).
Dissipated by the towers within no more than 0.3s
So that's 10¹⁰ J/s

WTC7 had a total potential energy of about 8*10¹⁰J
Dissipated during the collapse within about 16 seconds. With maybe the bulk of that within 8 seconds (just to keep my numbers round)
So that's 10⁹ J/s.
ETA: Oops - wrong: 10¹⁰ J/s[/B] also [ETA]

Again, I know little if nothing about seismology, but I would think that a high-power event triggers a higher seismic amplitude than a low-power event.
The plane crashes released (is that the word?) 10 times [ETA]about[/ETA] as much power (energy per time unit) than the collapse of WTC7, thus triggering a sharper seismic peak.

ETA: Okay, I need to sharpen my seismic reasoning

 

[Anders Lindman]

The planes had about, as I said, 3*10⁹J kinetic energy (+/- 13% or so, respectively).
Dissipated by the towers within no more than 0.3s
So that's 10¹⁰ J/s

WTC7 had a total potential energy of about 8*10¹⁰J
Dissipated during the collapse within about 16 seconds. With maybe the bulk of that within 8 seconds (just to keep my numbers round)
So that's 10⁹ J/s.


Again, I know little if nothing about seismology, but I would think that a high-power event triggers a higher seismic amplitude than a low-power event.
The plane crashes released (is that the word?) 10 times as much power (energy per time unit) than the collapse of WTC7, thus triggering a sharper seismic peak.

Oh. I didn't know that the energy released from the collapse of WTC 7 was smaller than the energy released from the plane impacts. That sounds incredible.

 

[DGM]

Oh. I didn't know that the energy released from the collapse of WTC 7 was smaller than the energy released from the plane impacts. That sounds incredible.

The energy release was not "smaller" the impulse (peak) was. Do you know the difference?

 

[Oystein]

...The seismic signal from the collapse of WTC 7 ...

Ok, I am confused now. Don't remember seeing the seismic signal for WTC7. We have 5 events here, and jumping back and forth.

I'd appreciate it someone could make five post, one for each of the five events (WTC1 plane, WTC2 plane, WTC2 collapse, WTC1 collapse, WTC7 collapse), and present the seismic signals for each, with charts in comparable scales, and explain what is shown in each.
Because I sure lost where we are now.