controlled demolitions, 1993 WTC bombing, Other skyscraper fires
– Arthur Lerner-Lam, Lamont-Doherty Earth Observatory, Palisades, New York.
Damage to buildings near World Trade Center Towers caused by falling debris and air pressure wave, not ground shaking, seismologists report
LDEO Columbia (Kim) WTC Seismic Waves (PDF)LDEO HTML (compressed seismographs)
LDEO Magnified WTC Seismograph Recordings
Seismic Waveform Review
Pop Mechanics on LDEO seismic data
JREF: Spins on S-waves, P-Waves, Rayleigh waves
"Scholars for Truth" Gordon Ross and Craig T. Furlong write a paper claiming that an explosion at the WTC was recorded by seismic instruments before the first aircraft impact. They forgot to check one little thing... (note: "quickandthedead" is Mr. Furlong, who has since renounced this paper and has joined the "debunking" camp.)
"Several demolition teams had reached Ground Zero by 3:00 pm on 9/11, and these individuals witnessed the collapse of WTC 7 from within a few hundred feet of the event.
We have spoken with several who possess extensive experience in explosive demolition, and all reported seeing or hearing nothing to indicate an explosive detonation precipitating the collapse.
As one eyewitness told us, "We were all standing around helpless...we knew full well it was going to collapse. Everyone there knew. You gotta remember there was a lot of confusion and we didn't know if another plane was coming...but I never heard explosions like demo charges. We knew with the damage to the building and how hot the fire was, that building was gonna go, so we just waited, and a little later it went."
... "Any detonation of explosives within WTC 7 would have been detected by multiple seismographs monitoring ground vibration in the general area. No such telltale 'spike' or vibratory anomaly was recorded by any monitoring instrument."
Everything.com topic: controlled demolitions
Welcome to The World of Explosives
JREF Huntsman on cutter charges
Linear Shaped Charges
Use and effects of steel cutter charges.
A few pounds of cutter charges = huge boom and flash.
JREF kookbreaker photos of I-beam cut with cutter charges, copper fragments, debris
WTC 9/11 Did the FBI test for explosives?
Bomb technicians from several federal and state agencies assisted during the World Trade Center attacks. Among other activities that day, they searched vehicles along the adjoining streets for suspicious packages, determining whether hidden explosives might be involved.
Training for this dedicated and hazardous work comes from the Federal Bureau of Investigation’s Hazardous Devices School, which opened in 1971. The Port Authority’s police were given similar training on hazardous and explosive materials to ensure better protection of the World Trade Center after the 1993 bombing.
Explosive detection dogs work closely with the bomb technicians. For over a century, specially trained dogs have assisted with law enforcement. Today, they are especially valued for providing additional security for visiting dignitaries and at airports. Breeds such as German shepherds and Labrador retrievers are used for this highly trained work. Source
Video: Detonation of 160kg TNT, simulation of a car bomb
Video: detonation of about 100 tons of TNT equivalent (less than would be requited to turn the concrete in the floors of one tower to powder, as the conspiracists claim happened.
10 Controlled demolition videos
Videos: Jowenko demolitions
JREF numerous Controlled Demolition comparison videos
Controlled Demolition, Inc. building demolitions
Controlled Demolition, Inc. says no CD of towers.
JREF: rwguinn on basics: a CD creates structural damage.
JREF: R. Mackey on collapse times and energy needed to destroy the structure
BAUT Forum: Jaydeehess on Hoffman/Ross calculations of energy needed to pulverize concrete
JREF: Huntsman, trained as a combat engineer, on feasibility of WTC CD
JREF: Gravy on feasibility of explosive demolitions of WTC buildings
JREF: Manny with some common sense about "squibs"
JREF: cloudshiprule on "explosives in basement" claim
Ryan Mackey on explosive energy of jet fuel, amount needed to damage basement levels
One of my first posts about this issue, which was brand new to me
Reporter says not an explosion in north tower (at 3:50)
Conspiracists try to use this audio to support their CD claims, as if a news reporter is an expert. However, listen: Peter Jennings says fire brought tower down.
Van Romero on conspiracist harassment
Los Angeles First Interstate Bank Fire May 4, 1988
"Engineers later discovered that the building survived the fire with surprisingly limited structural damage; credit was given to especially thick layers of a relatively heavy, cementlike fireproofing that had been applied to structural steel. The World Trade Center had the much lighter, easily dislodged fireproofing on the floor braces whose failure probably initiated the collapse." Source $NYT [Of course, the WTC buildings were also severely damaged.]
The 1975 World Trade Center Fire
1 New York Plaza Fire
"Light, spray-on fireproofing, which at some point had been knocked away, left steel supports for the floors exposed to the blaze. They twisted and pulled away from their connections, initiating collapses that stopped only because the concrete slabs of the floors refused to give way."
Madrid Windsor Bldg fire: U. Manchester good analysis
Explosions heard in Madrid Windsor Building fire
Tower Disaster Echoes Lessons Of Earlier Fires ($ NYT April 2, 2002)
EXPLOSION AT THE TWIN TOWERS: The Overview; BLAST HITS TRADE CENTER, BOMB SUSPECTED; 5 KILLED, THOUSANDS FLEE SMOKE IN TOWERS New York Times, Published: February 27, 1993
The blast, which erupted at 12:18 P.M. on the second level of a four-story underground parking garage beneath the trade center's 110-story twin towers and the complex's Vista Hotel, sent cars hurtling like toys, blew out a 100-foot wall and sent the floor collapsing down several stories, creating a crater 60 feet wide that reached deep into the bowels of the parking complex. 'Everything Was on Fire'
It also collapsed the ceiling of a mezzanine in the adjacent Port Authority Trans-Hudson train station, leaving dozens trapped under rubble on a concourse one floor above the platforms where hundreds awaited trains. Witnesses and rescue workers told of a blast of incredible force -- of bodies hurtling through the air, of cars wrapped around pillars, of people burning and scores trapped.
..."We crawled under pipes when we arrived and everything was on fire," said Edward Bergen, a 38-year-old firefighter who was one of the first to reach the scene of the blast. "Suddenly, a guy came walking out of the flames, like one of those zombies in the movie, 'The Night of the Living Dead.' His flesh was hanging off. He was a middle-aged man." Source
EXPLOSION AT THE TWIN TOWERS: The Scene; First, Darkness, Then Came the Smoke
New York Times, Published: February 27, 1993
It depended on where you were in the towers when it came. For some the warning was a trembling underfoot or just a blank computer screen and flickering lights. For others, it was a shocking noise. One woman was blown out of her high heels. Another, desk chair and all, sank into the floor. And then, instantly it seemed, came the billowing smoke and the chilling realization that you had to get out of there. The Face of Death
There were those who panicked, those who coolly absorbed it, those who got sick to their stomach and those who saw the face of death. No one was sure what had happened; did a plane hit the building, was it an earthquake, had lightning struck? Many wondered why there seemed to be no evacuation plan and no guidance -- not realizing that the blast had knocked out the center's operations center.
But thousands of people in the World Trade Center yesterday afternoon knew they were in the grip of one of the most dreaded urban nightmares: they were in the city's tallest building and something was very wrong.
Joann Hilton was low. And, in this disaster, that was the worst place to be. A secretary working for the Port Authority of New York and New Jersey, she was at her desk in the command office on the B1 level of the building, musing about the weekend.
"All of a sudden, we heard this big boom," she said. "It sounded like an earthquake. And then the floor just collapsed and me and my chair sank into the floor. The ceiling started to come down, too, and I'm in my chair in the floor. Some of the lights went out. And then it was all dark. Like a cave. Somebody pulled me out of that floor and we beat it out of there."
Denise Bosco was high. She was on the 82d floor, where she too works as a secretary for the Port Authority. "The whole building shook," she said. "The lights flashed on and off. The computers went down. Then, instantly, there was smoke. I was terrified. People panicked. They started pushing and shouting to get out. Some of them were throwing up. I said, 'Oh dear God, what is it? What is it? Is it my time? Is this the way?' "
Who is Ramzi Yousef? And Why it Matters (1995)
1993 bombing informant Emad Salem good JREF post by yodaluver28
Popular Mechanics article on rebuilding after 1993 blast
"Numerical simulation of blast in the World Trade Center" Baum, Joseph D; Luo, Hong; Loehner, Rainald AIAA, Aerospace Sciences Meeting and Exhibit, 33rd, Reno, NV; UNITED STATES; 9-12 Jan. 1995.
Study of Occupant Behavior During the World Trade Center Evacuation: Preliminary Report of Results., 1995
Human Behavior in the World Trade Center Evacuation. March, 1997
On February 26, 1993, shortly after noon, a bomb exploded in a subterranean garage below the World Trade Center plaza in New York City. The explosions and subsequent fire caused extensive structural damage on several basement levels, interfered with the operation of the fire protection and other emergency systems and resulted in the evacuation of over 100,000 occupants of the complex....
An explosion below the World Trade Center plaza in New York City on February 26, 1993, killed six workers, and resulted in injuries to over 1,000 occupants as they made their way out of the affected buildings. The explosion and subsequent fire caused extensive structural damage on several basement levels, interfered with the operation of the fire protection and other emergency systems and resulted in the evacuation of tens of thousands of occupants of the complex....Enhancement of EXIT89 and Analysis of World Trade Center Data. Final Report. August 1994-August 1995.
The features of an enhanced model for egress from fires in non-residential occupancies is presented along with a users manual describing the use of the model. The enhancements to the model include analysis of locations of safety, smoke blockages, disabled occupants, and delays in egress....
2005 Judgment about 1993 claims: Port Authority Fears Costs From Verdict ($ NYT Oct. 28, 2005)
Lawyers for the roughly 400 plaintiffs have said they would seek up to $1.8 billion in the 1993 World Trade Center bombing.
Port Authority Found Negligent in 1993 Bombing ($ NYT) The jury found that the agency did not heed warnings that the underground garage was vulnerable to terrorist attack.
(Excerpt) The burden on the plaintiffs was to show that the Port Authority should have foreseen the likelihood of a terrorist attack and taken steps to prevent it.
In order to reach a verdict, at least five of the six jurors had to agree. The jury voted unanimously that the Port Authority was negligent. It found the authority 68 percent at fault for the bombing, while the terrorists who carried it out were 32 percent at fault.
Mr. Dean, the plaintiffs' lawyer, said that because the jury apportioned more than half the blame to the Port Authority, the agency will have to pay 100 percent of any damages for pain and suffering, the so-called non-economic damages, that might be awarded.
Regardless of how the blame was shared, the Port Authority would have to pay 100 percent of any economic damages, like lost business, he said.
The jury deadlocked, 4 to 2 in favor of the Port Authority, on whether that negligence rose to the level of recklessness.
The plaintiffs, however, indicated that they considered the 4-to-2 vote a hung jury, leaving open the possibility of a retrial on that question. Mr. Kasowitz, the Port Authority lawyer, said he considered the verdict on recklessness a no vote. Justice Nicholas Figueroa said that the lawyers would return to court to discuss that portion of the verdict.
During the four weeks of testimony, the trial focused on a 1985 report by the Office of Special Planning, an antiterrorist task force convened by Peter Goldmark, who was the executive director of the Port Authority from 1977 to 1985.
Mr. Goldmark created the office in 1984, after becoming concerned that, given terrorist activities in other parts of the world, the trade center, as a symbol of American capitalism and strength, could be a target. After a visit to Scotland Yard in London that year, he wrote a memo saying that Scotland Yard was ''appalled'' that there would be public transient parking beneath a facility like the World Trade Center.
The report concluded: ''A time-bomb-laden vehicle could be driven into the W.T.C. and parked in the public parking area. The driver would then exit via elevator into the W.T.C. and proceed with his business unnoticed. At a predetermined time, the bomb could be exploded in the basement. The amount of explosives used will determine the severity of damage to that area.''
Among the report's recommendations was: ''Eliminate all public parking in the World Trade Center.'' It also recommended a series of compromise steps, including guarded entrances to the parking lots, random searches of vehicles and restrictions on pedestrian access.
The report came out about four months after Mr. Goldmark left the Port Authority, and his successors decided not to close the public lot, citing the potential loss of revenue and inconvenience to tenants, according to evidence at the trial. They also decided against most of the compromise measures.
In 1991, according to the testimony, the Port Authority commissioned a second report, from Burns and Roe Securacom, a private security company. That report found that the major risk to the trade center was from a package or hand-held bomb, and that the shopping and pedestrian areas, not the parking garage, would be the most likely targets.