All high explosives are detonated by pressure. Speed equals pressure and electricity has the speed to do it although it is difficult to get the arc from a spark contained with high explosive enough to exert the pressue on the explosive. That is what initates a blasting cap which is filled with a very sensitive high explosive in a small tight area to facilitate the chain reaction.Originally Posted by AuGmENTor
The powerdown provided the time to set detonators in the floors and perhaps the upper core area. The security phone schematics from securacom facilitated designing a system using digital counters with the appropriate delays and the effect seen.
I too feel some thermite was used above ground level as a distraction at the very least but it appears by the molten metal pouring out of WTC I think it was that perimeter box columns may have been cut to facilitate WTC falling east as it did. Most of the thermite was in the basement however. Tons of it to severe the huge interior box columns which not even explosives could cut effectively.
The 1993 bombing provided and excuse for a remodel and the installation of that.
