High-Tech Methods Are Used to Assess Damage After Terrorist
  Attacks

  By JEFFREY R. YOUNG
 
   Equipped with lasers or customized Palm Pilots, teams of
  university researchershave been assessing the damage done to
  the buildings surrounding the World Trade Center during the
  September 11 terrorist attacks.
 
  The groups, many of them supported by the National Science
  Foundation, are using new high-tech methods developed for
  surveying earthquake and hurricane damage -- but in this case
  the researchers are making sure that the buildings surrounding
  the fallen trade towers are safe to reoccupy. Some of the
  assessment techniques have never been used in the field.
 
  One of the researchers who raced to study the incident was
  David Bloomquist, an associate professor of civil and coastal
  engineering at the University of Florida. Officials from the
  Defense Department asked Mr. Bloomquist and other Florida
  researchers to use an airborne laser to map the damage done to
  lower Manhattan.
 
  The laser-measuring device is capable of determining the
  topography of an area to within a one-centimeter margin of
  error. That is far more detailed than traditional methods,
  which rely on aerial photography. The team will remap the area
  in the coming weeks to look for shifts in the structures.
 
  The team also plans to use a ground-based laser system to map
  portions of Ground Zero, and to combine that information with
  the aerial data to increase the resolution of their maps even
  further. When combined, the data will be used to make
  "three-dimensional models of the disaster sites far more
  detailed and accurate than has ever before been available to
  recovery workers and planners," according to a grant proposal
  submitted to the NSF by the researchers.
 
  Unfortunately, the university's airborne laser was in the shop
  for an upgrade at the time of the attacks, so the team raced
  to borrow another laser system, with the help of the National
  Oceanic and Atmospheric Administration. Twelve days after the
  attacks, some of the researchers were on their way to New
  York.
 
  Crisscrossing the sky
 
  Michael Sartori, a research coordinator for the group, and a
  graduate student, Devon Drake, drove a sport-utility vehicle
  from Gainesville to Ground Zero because they did not want to
  fly. "Every overpass had an American flag on it," says Mr.
  Sartori.
 
  "I was glad to go and be part of it," he adds. "We felt like
  we were able actually to do something."
 
  Mr. Sartori was on ground duty while the plane equipped with
  the laser system crisscrossed the sky above Manhattan at 3,800
  feet -- high enough so that it would not worry residents who
  might fear another attack. He stood in a field near a New
  Jersey airport using a global-positioning system that tracked
  the airplane's progress. That night, Mr. Sartori began
  analyzing the data in his hotel room, using a desktop computer
  he brought with him.
 
  "We've got over 100 million data points collected," says Mr.
  Bloomquist. From the data, the team has already generated
  haunting three-dimensional computer images of the area.
  Because the software they use was designed to assess
  geological features, the buildings and streets around Ground
  Zero look like a series of cliffs and valleys, with a crater
  where the trade towers once stood. Some of the images are
  available on the university's Web site
  (http://www.alsm.ufl.edu/research/wtc/WTC.htm).
 
  In the next few weeks, the team plans to make another flyover
  and to compare the two sets of data. The university's own
  airborne laser system will be back in operation by then, and
  Mr. Bloomquist, who is a licensed pilot, intends to fly a
  twin-engine Cessna with the laser over the trade towers'
  remains.
 
  "With the laser you can say a building has shifted a
  centimeter on this end," says Mr. Bloomquist. "From the naked
  eye you couldn't tell."
 
  As the researchers spell out in their grant proposal, some
  buildings may be faltering. "Several surrounding buildings
  near Ground Zero may not be structurally salvable, and there
  is concern that several are slowly deteriorating from a
  structural standpoint," they wrote.
 
  Meanwhile, a team of scholars from the Georgia Institute of
  Technology traveled to Ground Zero with Palm Pilots equipped
  with customized software to help them record the damage done
  to surviving buildings. They arrived just two weeks after the
  attacks, in part because they wanted to document the damage
  before anything changed.
 
  Electronic Records
 
  James David Frost, an engineering professor at Georgia Tech,
  originally developed the Palm Pilot software, which he calls
  PQuake, to log building damage done by earthquakes
  (http://www.prism.gatech.edu/~sd89/doctoral.html). The
  software features a series of menus that make it easy to
  record the structural characteristics of buildings while the
  researcher is looking at them. Using GPS, the software can
  match the researcher's exact location with the data gathered
  during each observation.
 
  Mr. Frost says a key benefit of the software is that it makes
  it easy to keep notes and pictures organized, and to share
  them with colleagues. "It means I can just send you my files
  electronically, and I don't have to be sitting beside you
  saying this is the photo that goes here."
 
  As horrible as the destruction was, Mr. Frost says that there
  was less damage than he expected to some structures near the
  fallen trade towers.
 
  In many cases, he says, "the integrity of the building is
  probably not compromised." But he added that due to cosmetic
  damage done to the buildings, it could be "six to nine months"
  before buildings with even minimal damage can be reoccupied.
 
  Researchers from various groups who are assessing damage at
  Ground Zero are also working to create a joint database to
  share information. New York University is organizing a
  workshop on December 12-13 for the various teams to meet and
  share their findings.