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Seismic event indicating explosion at WTC

Anders Lindman said:
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.
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Computed Origin Time = Time when PAL detects a signal minus time for the signal to reach PAL from its point of origin (34 km / 2 km/s = 17s)

The diagram shows :
1. Something occured there : the arrow
2. It took 17s to reach PAL : the 17 seconds with no signal
3. PAL detects it : the signal
 
Lak said:
Computed Origin Time = Time when PAL detects a signal minus time for the signal to reach PAL from its point of origin (34 km / 2 km/s = 17s)

The diagram shows :
1. Something occured there : the arrow
2. It took 17s to reach PAL : the 17 seconds with no signal
3. PAL detects it : the signal
Click to expand...

[EDIT: Correction, what I thought was a mistake is not a mistake] No, that's the same mistake I made earlier. The start arrow points to the tiny first signal arriving at the PAL station.
 
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Lak said:
No.The start arrow points to the :
Computed.
Origin.
Time.

It's what is written. Please read.
Click to expand...

[EDIT: My mistake, the signal does NOT start at the arrow, so this post is false] To the computed origin time, yes, but the signal starts at the arrow! I made the same mistake earlier because the first part of the signal is so tiny (containing high-frequency components). Compare with the arrow for the earthquake signal. There the start of the tiny signal is more visible:

http://img715.imageshack.us/img715/6177/72044115.gif

Edited by LashL: 
Removed repetitive image. See Rule 6.
 
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Anders Lindman said:
To the computed origin time, yes, but the signal starts at the arrow! I made the same mistake earlier because the first part of the signal is so tiny (containing high-frequency components). Compare with the arrow for the earthquake signal. There the start of the tiny signal is more visible:

[qimg]http://img715.imageshack.us/img715/6177/72044115.gif[/qimg]
Click to expand...
Are you claiming the ripple at the arrow is something?
 
Anders Lindman said:
I have only seen an explanation about how the 9/11 Commission could have made a mistake about the 5 seconds inconsistency, but nothing about the 17 seconds inconsistency for the second plane impact.
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A search of the commission report for "seismic" fails to come up with any use of LDEO timing or use of seismic data with which to base it's conclusions for WTC.

In this memo. NIST describes how it established an accurate timebase for events at WTC. It post-dates the 9/11 commission and any comparison of times taken from the two reports to the second level is inherently flawed.

The Commission report was historical, not technical. Unlike the NIST report, it's conclusions are not based on second-level calibration of disparate clocks, always a problem.
 
Anders Lindman said:
But let's assume that the seismic data is correct, then the 17 second inconsistency for the second plane impact in the official 9/11 commission report has to be explained. So how do you explain that?
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Cite the page in the report please.
 
Anders Lindman said:
The origin time may be unclear when it comes to the collapses, but for the plane impacts the origin times are clear since these were short events at the source, unlike the collapses which went on for several seconds. And the 17 second inconsistency in the official report is about the second plane impact.
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But you have said there were no planes.

If there were no planes, how can there be plane impacts on the seismic data?

<cognative dissonance>
 
BigAl said:
A search of the commission report for "seismic" fails to come up with any use of LDEO timing or use of seismic data with which to base it's conclusions for WTC.

In this memo. NIST describes how it established an accurate timebase for events at WTC. It post-dates the 9/11 commission and any comparison of times taken from the two reports to the second level is inherently flawed.

The Commission report was historical, not technical. Unlike the NIST report, it's conclusions are not based on second-level calibration of disparate clocks, always a problem.
Click to expand...

That NIST document says: 9:02:59 for the second plane impact. Ok, then the time difference is only 5 seconds compared to the seismic data. The start of the collapse of the South Tower is the same in both the NIST document and the 9/11 Commission Report: 9:58:59. Here there is also a 5 seconds difference compared with the seismic data.
 
Anders Lindman said:
That NIST document says: 9:02:59 for the second plane impact. Ok, then the time difference is only 5 seconds compared to the seismic data. The start of the collapse of the South Tower is the same in both the NIST document and the 9/11 Commission Report: 9:58:59. Here there is also a 5 seconds difference compared with the seismic data.
Click to expand...
Do you really think all clocks are synchronized to the second? The precision they state is for the computed time (over distance).
 
TruthersLie said:
But you have said there were no planes.

If there were no planes, how can there be plane impacts on the seismic data?

<cognative dissonance>
Click to expand...

I have said that there could have been no planes yes. Then then staged explosions for simulating the impact of a plane would have caused the seismic signals.
 
DGM said:
Do you really think all clocks are synchronized to the second? The precision they state is for the computed time (over distance).
Click to expand...

Are you sure? Origin times are used also for earthquakes. Surely they must have precise clocks for that?
 
Anders Lindman said:
That NIST document says: 9:02:59 for the second plane impact. Ok, then the time difference is only 5 seconds compared to the seismic data. The start of the collapse of the South Tower is the same in both the NIST document and the 9/11 Commission Report: 9:58:59. Here there is also a 5 seconds difference compared with the seismic data.
Click to expand...


The 9:58:59 is vaguely sourced, possibly from a NEADS audio tape. Expecting two disparate clocks to be synchronized to the seconds by accident is madness.
 
BigAl said:
Yes, but it's the other clock that is the source of uncertainty.
Click to expand...

Oh. I see your point. It's not easy to establish the exact time for a sudden event like that, BUT when the second plane hit the WTC they KNEW that the first plane had already hit the other tower and must have had very precise time measurement and all kinds of surveillance directed towards the WTC towers when the second plane hit. Or?
 
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