Likely bin Laden Hideout Identified
 Distance-decay theory predicts that Osama bin Laden is closest to the point where he was last reported. UCLA geographers say there's a 98 percent probability that he's in Kurram, a Federally Administered Tribal Area in Pakistan.) |
While U.S. intelligence officials have spent more than seven years searching for Osama bin Laden, geographers say they now have a good idea of where the terrorist leader was at the end of 2001 and may know where he has been in the years since.
In a new study published online by the
MIT International Review, the UCLA researchers report that simple facts, remote-sensing satellite imagery and fundamental principles of geography place the mastermind behind the September 11 attacks against the U.S. in one of three buildings in the northwest Pakistan town of Parachinar, in the Kurram tribal region near the border with Afghanistan. The findings are based on the last information on bin Laden's whereabouts to be made public by U.S. intelligence sources, who have closely guarded the details of any efforts to locate him.
"If he's still alive, he honestly could be sitting there right now," said Thomas W. Gillespie, the study's lead author and an associate professor of geography at UCLA. "It is still the safest tribal area and city in the Federally Administered Tribal Areas (FATA) of northwest Pakistan and one of the only tribal areas that the U.S. has not bombed with its unmanned Predators."
"We believe our work represents the first scientific approach to establishing bin Laden's current location," said John A. Agnew, study co-author and UCLA geography professor. "The methods are repeatable and could easily be updated with new information obtained by the U.S. intelligence community."
The findings rely on two principles used in geography to predict the distribution of wildlife, primarily for the purposes of designing approaches to conservation. The first, known as distance-decay theory, holds that as one travels farther away from a precise location with a specific composition of species — or, in this case, a specific composition of cultural and physical factors — the probability of finding spots with that same specific composition decreases exponentially. The second, island biogeographic theory, holds that large and close islands have larger immigration rates and will support more species than smaller, more isolated islands.
Inspired by distance-decay theory, the seven-member team started by drawing concentric circles around Tora Bora on a satellite map of the area at a distance of 10 kilometers — or 6.1 miles — apart.
"The farther bin Laden moves from his last reported location into the more secular parts of Pakistan or into India, the greater the probability that he will be in an area with a different cultural composition, thereby increasing the probability of his being captured or eliminated," Gillespie said.
Then, informed by island biogeographic theory, the researchers scoured the rings for "city islands" — distinctly separate settlements of considerable size.
"Island biology theory predicts that he would find his way to the largest but least isolated city of that area," said Gillespie, an authority on measuring and modeling biodiversity on Earth from space. "If you get stuck on an island, you would want it to be Hawaii rather than one with a single palm tree. It's a matter of resources."
 Located in northwest Pakistan, Parachinar is 12 miles from Tora Bora, the last confirmed location of Osama bin Laden. |
The approach netted 26 cities within a 12.4-mile radius of Tora Bora on imagery from Landsat Enhanced Thematic Mapper Plus (ETM+), a global archive of satellite photos managed by NASA and the U.S. Geological Survey. With a 2.7-square-mile footprint, Parachinar turned out to be the largest and fourth-least isolated city, the team determined.
"Based on bin Laden's last known location in Tora Bora, we estimate that he must have traveled 1.9 miles over a 13,000-foot-high pass into Kurram and then headed for the largest city, which turns out to be Parachinar," said Agnew, who is the current president of the Association of American Geographers, the field's leading scholarly organization.
The researchers ruled out cities on the Afghanistan side of the border because the country was occupied at the time by U.S. and international forces and has been particularly unstable ever since.
Faced with the prospect of picking from more than 1,000 structures clearly portrayed in the satellite imagery of Parachinar, the team decided to come up with a short list of the criteria that bin Laden would need for housing, based on well-known information about him, including his height (between 6'4" and 6'6"), his medical condition (apparently in need of regular dialysis and, therefore, electricity to run the machine) and several basic assumptions, such as a need for security, protection, privacy and overhead cover to shield him from being spotted by planes, helicopters and satellites.
So, they looked for buildings that could house someone taller than 6'4" and were surrounded by walls more than nine feet tall (both as judged by mid-afternoon shadows depicted on the satellite imagery), and that had more than three rooms, space separating them from nearby structures, electricity and a thick tree canopy.
Only three structures fit the criteria. The buildings also appeared to be the best fortified and among the largest in Parachinar. Two are clearly residences, the study states. The third may be a prison. But whatever the third structure is, it has "one of the best maintained gardens in all of Parachinar," the study says.
While the three structures meet all six of the criteria that the researchers believe would be required for lodging bin Laden, an additional 16 structures in Parachinar appear to meet five of the six criteria. If bin Laden is not in the first three structures, the U.S. military should investigate these other buildings, the study urges.
Undergraduates had attempted to take on the same study in 2006, but at 30 x 30 meters — or nearly 100 x 100 feet — the resolution of publicly available satellite images of the area at the time was insufficient. In contrast, today's resolution is 0.6 meters, or just under 2 feet, Gillespie said.
"Technology has caught up to the question," said Gillespie, who serves as the director of the Spatial Demography Group for the UCLA-based California Center for Population Research.
Due to the low cost of conducting the study, it received no outside funding. However, past research by Gillespie has received funding from the National Institute on Aging, the MacArthur Foundation and the National Science Foundation.