high explosive blast effects.

In an explosion the expanding gases push compressed air ahead of their expansion creating the blast wave. It’s reflection can cause a mach stem to form and this video shows mach stem formation from a conventional explosive
www.atomicarchive.com...
My research so far leads me to believe that mach reflection can only be achieved with high explosives and that the effect would be pronounced with high yield high explosives. Mach reflection and also a mach stem are signatures of high explosive - they cannot exist without high explosive.

Note the turbulence at ground level in this picture
www.jasco.com...
which shows the mach stem from two blasts. The blast energy from an above ground blast will cause the pressure at ground level to be slightly greater than that above this level. This is caused by energy absorption at the ground causing the front at this level to move more slowly.
After the blast pressure drops to atmospheric there is a reversal of air flow and this can be most visually observable at ground level as debris at very low levels is sucked back towards the centre of the explosion, seemingly in the reverse direction to what would be expected. This is caused by the “inertia” of the material within the blast wave causing a slight over-expansion.
This is a phenomenon which I believe is most obvious by watching the blast patterns following nuclear explosions but is not limited to those and as the videos above show can be caused by above ground conventional explosions.
So after an explosion we would expect the debris at ground level to travel generally slightly upwards and towards the source of the blast, caused by the pressures mentioned above.

Now please examine this video and watch the ground level debris right at the end when the camera operator goes behind a vehicle.

terrorize.dk...

Note the direction that the camera operator runs.
Note the direction of the flow of near ground level dust and debris.
Note the direction from where the dust cloud arrives.

Gordon.
Edit to sort link. Thanks

[edit on 13-3-2006 by gordonross]

The Naudet clip is a broken link.

As it is in the st911 forum.

The link works just fine now.

Another nail in the coffin of the official fairytale, as if there weren't enough already. GJ gordon!

I think though that with enough good will, you can attribute the observed phenomenon to pancaking, somehow. Let's see: the pancaking floors created massive shockwaves by sudden air compression, similar in magnitude to high explosives. This makes sense, after all we could witness the explosive features of the collapse! And then...uh...steel melted in large quantities, because where there are pancakes, there must be a heat source nearby.

right click and save Jack.
Why you think it has it been cut/edited just when he was about to look up.


[edit on 13-3-2006 by The Links]

Ok got it.

Wow.

I don't know too much about this but there sure seems to be a correlation here!

Gordon is the man.

Way Above Top Secret vote for you buddy!

Anyone care to match?

Gordon mach stems require the explosion to occur above the ground.

When a bomb is detonated at some distance above the ground, the reflected wave catches up to and combines with the original shock wave, called the incident wave, to form a third wave that has a nearly vertical front at ground level. This third wave is called a "Mach Wave" or "Mach Stem," and the point at which the three waves intersect is called the "Triple Point." The Mach Stem grows in height as it spreads laterally, and as the Mach Stem grows, the triple point rises, describing a curve through the air. In the Mach Stem the incident wave is reinforced by the reflected wave, and both the peak pressure and impulse are at a maximum that is considerably higher than the peak pressure and impulse of the original shock wave at the same distance from the point of explosion. Using the phenomenon of Mach reflections, it is possible to increase considerably the radius of effectiveness of a bomb. By detonating a warhead at the proper height above the ground, the maximum radius at which a given pressure or impulse is exerted can be increased, in some cases by almost 50%, over that for the same bomb detonated at ground level.


Would the mach stem have occured only within the building?

If the detonation was inside the building then the blast would be reflected and contained inside. The explosives that I was referring to were the ones which detonated down the columns as the collapse front progressed.
(I've got some good stuff on this as well which should come out soon.)
Because they were detonated outside the building and up in the air the mach reflection would bounce off the ground and the stem would advance outwards. I know that mach reflection is indicative proof of high explosive but we need to know for definite whether the reverse flow at ground level is also an indicative proof. If that particular phenomenon is a signature then it is an even more convincing proof.
Any comments appreciated.
Links, I'll get back to you on the pent hole,
Gordon.

Maybe little off-topic but still about explosives. Is there something like implosion bomb ?

Well, the closest you might get is a thermobaric bomb, I suppose. In any case, after a detonation, i.e. the rapid expansion of gas, there's subambient pressure causing suction of surrounding gas, i.e. air in most cases.