by André Rousseau
translated from french by SOTT
from SOTT Website
according to geophysicist
André Rousseau (*)
Seismic signals were recorded on September 11
2001 during the period when the North and South Towers (respectively WTC1
and WTC2) were penetrated and collapsed, as well as during the collapse of
Building 7 of the WTC (also known as WTC7), a building which had not been
hit by a plane.
wave graphs are taken from the publications of the Lamont-Doherty Earth
Observatory of Columbia University (LDEO), as shown in figure 1 and figure
2 (bottom page.)
This text focuses on the study of seismic
signals and aims to demonstrate that consistency only appears once we leave
the official version of events. It gives rise to a new interpretation that
renders the assertions of the "official version" null and void.
A study of the propagation of such seismic signals really belongs to applied geophysics, which examines the distance of propagation in relation to the nature of the sources. Normally in this type of study, the time of origin is known with great precision (down to the millisecond), necessary in order to calculate the propagation speed of the different waves.
That isn't the case here. In this case, the video used for the North Tower (WTC1) was from a recording made by CNN with a time stamp on the screen (Hoffman, 2006), and the results were compared with the method utilized by Lamont (Kim et al., 2001). A second method consisted of giving an approximate speed of 2km/s for a Rayleigh wave that traversed several stations (see figure 3) situated at various distances from the point of origin.
The major inconvenience of this method is that the stations are not situated on a rectilinear line, that the surface terrain - in which the surface waves move - are different, and, moreover, they don't have the same speed of propagation. The Hudson River is located on a fault line that separates to the west the sedimentary terrains of the Trias and Jurassic, with intrusions of dolerite, all of which are covered by recent Holocene sediment; and to the east, the crystalline and metamorphic formations of the Proterozoic, the Cambrian, and the Ordovician eras that are found there.
These last formations are more rapid than those found to the west, which explains why the path WTC-MANY, the only site to the east of the Hudson, was more rapid than all the other paths, situated to the west.
The speed of these formations closely depend upon the sedimentary cover traversed. In other words, it isn't surprising to find that only the stations at Palisades (34 km), at Arny (67.5 km) and TBR (51 km) provide similar results because they are situated on similar geological formations.
Also, the enormous indetermination of 2 seconds
in the calculations fixing the time origin of each of the signals,
attributed by the authors themselves (Kim et al.), oblige us to take some
distance from the official conclusions.
Although the cause of the two signals is similar, the crashing of a plane, the magnitude (reflected by the amplitudes) of the two signals is different and the wave generated by the two do not have the same apparent speed (see figures 1a and 1b), even if the Twin Towers could be considered identical in terms of the spatial origin relative to their distance from the recording sites.
The calculation of the propagation speeds, as shown in the graphs of figures 1a and 1b, where the origin was fixed according to the corresponding crash, indicates 2900 m/s for WTC1 and 2150 m/s for WTC2: we are obviously dealing with Rayleigh waves.
Even if they were considerably amplified, these signals could not have been generated by the crashes into the Twin Towers - the actual waves generated by the crashes were deadened before hitting the ground (assuming that we were dealing with the same (low) frequencies).
Frequencies of waves generated by explosions are on the order of Hertz - which is the case here - while those of crash impacts are above 10 Hertz, often around 100 Hertz. Furthermore, the range of the recording instruments cited does not allow for the recording of such waves.
As to the theory of the oscillation of the
Towers to explain these signals, as defended by Irvine (2001), it doesn't
hold water because in such a case we would have had a "square" signal of
long duration and a constant amplitude, while in actuality we observe a
"bell" signal, representing a strong and brief explosion, which is
particularly evident in the case of WTC2.
As well, the difference in the magnitude of the
two signals can only be linked to different parameters relative to the
volume of explosives and/or their distance from the surface.
(fig. 2a, 2b and 2c)
This wave seems to be followed by a second
Rayleigh wave 6.7 seconds later.
In their publication on the Web (Kim et al., 2001), the LDEO published two different timetables of sources, which are indicated in the table below. The first timetable (LDEO ) is that furnished without the published graphs, then the LDEO modified them (LDEO ) to obtain coherent seismic speeds. What is the indisputable data here?
There are two: the time that the waves reached the Palisades station, which is relatively easy to determine, and the distance from the WTC to Palisades (34 km).
If the recorded wave is actually a Rayleigh wave, its speed is around 2000 m/s. Therefore, this wave was created 17 seconds before its arrival at Palisades. Where the problem deepens for the adepts of the official version is that the time for the source of the Rayleigh wave attributed to the crash into WTC1, which officially arrived at Palisades at 8.46.42±1, must in fact be 8.46.25±1!
Compare that time with the times given in the first column of the table below.
9/11 Seismic Study - Table 1
The data given by the NTSB (National Transportation Safety Board) comes from radars at ground level and are reliable to one second.
If we consider the time of the impact of the
plane into WTC1 furnished by the NTSB, 8.46.40 (Ritter, 2002), the only
reliable data because it doesn't come from any hypothesis, there is a hiatus
of 15 seconds between the plausible time of the origin of the Rayleigh wave
and the time - afterwards - of the crash of the plane into WTC1. What else
but an explosion could be the origin for this seismic wave in the absence of
However that is not the case here because we have two hollow and deformable objects. During the crash, the whole of the energy is transformed into heat and the deformation of the envelopes (exterior walls). In the case where a little mechanical energy would remain, the waves created in the pierced envelope would be quickly dispersed because of the absence of continuity in this alveolar envelope.
The necessary condition for the creation of seismic waves by such a crash would be the direct impact of the central columns by a full body.
Even if a Boeing engine had succeeded in hitting
a central column, it would have been with an energy lessened by the
envelope. In conclusion, even if a seismic wave could be created in a
metallic column, it would hit the ground in the form of a sound, and as the
passage from metal to rock is a refraction that absorbs energy, there
wouldn't be much left to propagate in the ground.
In the case of a crash on the ground that generates seismic waves, the enormous mass of the Twin Towers could hypothetically be taken into account if the Towers had fallen in a compact block, like a meteorite. But in the present case, it was scattered remains that fell, largely transformed into dust, and the fall lasted several seconds.
We are far from a Dirac-type force that can create seismic waves;
in this case, the magnitudes simply don't add up.
We must distinguish between subterranean explosions, subaerial explosions (close to the ground without touching it) and aerial explosions.
In brief, a subterranean explosion would not be
heard in the air, but the ground would shake and initiate a series of waves
(volume and surface waves), while if we hear an explosion, it is because it
is either "aerial" and doesn't give a seismic signal, or it is subaerial and
surface waves could be generated.
The sound coming from these explosions would
have been mixed with the sounds generated by the impacts of the planes (Case
3). The Towers were thus weakened by the breaking of the load-bearing
columns. The explosion at the base of WTC1 was heard by eyewitness Walter
Rodriquez (2006) (see also Spingola (2005)).
For example, regarding WTC2, a fireman witnessed an explosion before the building collapsed into an enormous cloud of dust (See ), apparently not too far from the base of the tower accompanied by flashes of light and noise, according to an "Assistant Commissioner" (see ).
Another fireman, present at the base of WTC2, stated there was a large explosion about 20 floors below the impact zone of the plane just before the summit of the Tower collapsed (see ).
These explosions were too high to generate volume waves in the ground, and the Rayleigh wave recorded probably comes only from the explosion closer to the ground. Among the other explosions heard at the base of WTC2 (Anonymous, 209), one of them generated the second Rayleigh wave four seconds after the first. The same thing happened at WTC7.
A witness watching this tower heard something
like a "thunderclap" that caused the windows to explode outwards, while the
base of the burning building gave way a second later, before the whole
building followed the movement (see ), aided by a second explosion that
generated the second Rayleigh wave 6.7 seconds later.
On the other and, it is also logical that the
many explosions shown in videos in the upper floors before and during the
collapse didn't provoke any seismic waves (Case 2) because of the
fragmentation in time of the detonated energy with the multiplication of
successive sources, each of which had only a limited force, insufficient to
generate seismic waves in the ground.
The case of the Kingdome is particularly interesting because seismologists expressly asked that the explosions be measured (they wanted to take advantage of the occasion), and those in Oklahoma City were part of a reconstruction using explosives of the bombing of the Alfred P. Murrah building. These two examples fit into Case 3 cited above, with a powerful subaerian explosion and the emitting of Rayleigh waves, and where the falling of the debris had no seismic consequences, even at distances under 34 km (less than 7 km and 26 km respectively).
Only the seismic equipment situated close to the
source during the reconstruction of the bombing in Oklahoma City reacted to
the seismic energy created by the collapse of the building.
Even if the entire tower had been compacted into a tight ball, it would have necessitated the speed of a meteorite, in any case, more than that caused by the Earth's gravity, to even approach such a magnitude!! Moreover, we must note that the magnitude attributed to the subterranean explosion at the WTC1 is LM=2.3 - comparable to the earthquake that hit New York January 17, 2001 (LM=2.4) - while the magnitude coming from the WTC2 explosion is LM=2.1, thus weaker, and this disparity - consistent with the explosions described - is particularly appreciable in this logarithmic scale.
Given the Twin Towers were of similar height and
mass, the falling debris should have generated similar magnitudes, if they
were the source of the waves...
But the energy of the waves developed in the
ground are too weak for the waves to go further than several hundred meters.
After that we must distinguish between the parts
of the building above the impact zone of the planes and those located below.
If the seismic waves couldn't have been generated by the small explosions
visible in the floors (which allowed for the gradual collapse from the
bottom up to the impact zone) then only a powerful explosion at the base of
both buildings could have accelerated the process of total ruin and produce
the observed seismic waves.
They note that,
As this transmission tower was a lattice of I Beams posed diagonally, called a "hat stress", it connected the walls of the edge to the central structure between the 107th stage and the roof and therefore reinforced the centre structure. It also supported the tower installed on the top of the building.
Contrary to the official version which declared
that it was the hat stress that transferred the instability of the central
columns to those of the perimeter, which then gave out after they were
deformed because of the pulling of the floors, the logic of the events
forces us to consider that the "rupture" of the central columns came from an
explosive "cutting" prior to the collapse of the building.
To the degree that:
Even if the planes' impact and the fall of the
debris from the Towers onto the ground could have generated seismic waves,
their magnitude was insufficient to be recorded 34 km away, and they should
have been similar.
The placement of the source of the four other
explosions is subaerial, attested by the unique presence of Rayleigh waves.
The aerial explosions visible on the videos of the upper floors of the Twin
Towers do not produce seismic waves 34 km from the source.
recorded at Palisades during the impact on WTC1.
Signal recorded at Palisades during the impact on WTC2.
Signal recorded at Palisades during the collapse of WTC1.
Signal recorded at Palisades during the collapse of WTC2.
Signal recorded at Palisades during the collapse of WTC7.
Shift of origin time of WTC1.