Quote:


Asked what could have caused such extreme heat, Tully said, "Think of the jet fuel."



The mass of that build falling through a 1 G gravitational field for 500+ feet is going to release a lot of energy, easily this much. It would have been shocking to not find significant temperatures and melting.

Quote:


The hottest spots at the surface of the rubble, where abundant oxygen was available, were much cooler than the molten steel found in the basements.



Because the surface rubble can radiate heat into a cool sky whereas buried rubble can only lose heat through insulating material (rocks, etc) to other hot areas. Just like why the planets are still so hot 5B years after forming.

Quote:


"If the first event was the falling of a floor, how did that progress to the severing of hundreds of columns?"



I'm sorry, I just can't here. It's too stupid.

Quote:


While the aircraft crashes caused minimal earth shaking, significant earthquakes with unusual spikes occurred at the beginning of each collapse.



Maybe because the buildings were more massive , and not impacts on a flexible arm that redistributed the energy.

Quote:


However, the Palisades seismic record shows that-as the collapses began-a huge seismic "spike" marked the moment the greatest energy went into the ground. The strongest jolts were all registered at the beginning of the collapses, well before the falling debris struck the Earth.



"well before" - I wonder how accurate the timing is here.

When St. Helens erupted everyone assumed the earthquake caused it. Then when careful analysis was done later it was realized there was no earthquake per se: it was the debris from the side of the mountain hitting the ground that caused the seismic event.

It was a grad student who figured it out - even the professors had assumed the start of the St. Helens seismic event coincided with the eruption and not second(s) later. So not too many demerits for assumptions here.

Quote:


Experts cannot explain why the seismic waves peaked before the towers actually hit the ground.



That pesky word "before" again. Anyone want to bet that the peak was when the collapse reached the basements - impacted bedrock - and that the rest of the event is debris settling onto material that had already landed on the pile?

For that matter, want to bet the entire event was equal in duration to the time for the mast to fall from its original height to the ground and that the amplitude fell off as the debris pile presenting a softer landing cushion, not well coupled to bedrock, even though higher floors had fallen further?

Quote:


Lerner-Lam told AFP that a 10-fold increase in wave amplitude indicates a 100-fold increase in energy released. These "short-period surface waves," reflect "the interaction between the ground and the building foundation," according to a report from Columbia Earth Institute.



Right - when the basement collapses onto bedrock it impacts relatively rigid bedrock. But the debris pile is compressible - the pile didn't form into a perfectly solid mass free of air pockets as it fell - and not rigidly coupled to bedrock.

Quote:


"Only a small fraction of the energy from the collapsing towers was converted into ground motion," Lerner-Lam said. "The ground shaking that resulted from the collapse of the towers was extremely small."
.
Last November, Lerner-Lam said: "During the collapse, most of the energy of the falling debris was absorbed by the towers and the neighboring structures, converting them into rubble and dust or causing other damage-but not causing significant ground shaking."



Oops - they accidentally identified the source of the heat mentioned at the top.
_________________________
"If they can't picture me with a knife, forcing them to strip in an alley, I don't want any part of it. It's humiliating." - windsock