OSAKA, Japan — Just six years after its completion, Japan's second-largest airport is way ahead of expectations in one respect: It is sinking into the ocean much faster than planned.
Spread out on an artificial island that cost $17 billion to build, the much-touted gateway to western Japan is "settling" at a pace 44 years ahead of schedule. Experts claim that everything is under control, but their words are failing to check growing alarm and anger.
"How much longer will this last?" opposition lawmaker Yoshiaki Takagi asked at a recent session of Parliament's transportation committee. "This raises questions about the airport's safety and its credibility."
Kansai International Airport opened in the bay off Osaka, Japan's second largest city, in 1994 after nearly seven years of construction. It has become a major Asian transportation hub, handling nearly 20 million passengers last year.
The airport was designed to provide relief for passengers previously obliged to use Tokyo's airport, which is an inconvenient 40 miles outside the capital and where separate facilities for international and domestic flights create more headaches for fliers.
The Kansai airport combines both kinds of flights and is convenient to Osaka and its two neighbors, Kobe and Kyoto.
Few would call it a success story, however. Building the airport cost twice what was originally projected, and it has yet to post a profit: In fiscal 1999, it lost $1.4 billion.
Creating the 1,275-acre island in an area notorious for earthquakes presented special technological challenges. The year after it opened, Kobe and some parts of Osaka were flattened by a quake. To the surprise of many, the airport survived the quake with minimal damage.
But because the airport sits on relatively soft ground, officials knew sinkage would be a long-term problem. They originally estimated it would settle no more than 38 feet over 50 years.
They were way off.
The airport had already sunk that much by last December, even though its opening was delayed one year so that thousands of tons of additional gravel could be poured in to stabilize the structure after sinkage projections were revised in 1992.
Sinkage is worst around the island's center, where key airport facilities are housed. Of the airport's 17 monitoring sites, five, including the main terminal and part of its 3,850-yard runway, have reached or exceeded their 50-year sinking projection.
The terminal, for example, is already eight inches lower than it was expected to sink after 50 years. Hydraulic jacks used to lift columns correcting the tilt of the terminal building have already been made longer, because the terminal has sagged so much already that the jacks' 12-inch reserve length has been used up.
"Parts of the airport have sunk more than we expected," acknowledged Naoki Hayashi, general manager of the engineering department at the Kansai International Airport Co. "There is nothing we can do to stop the sinking itself."
In what they hope will be the final "precautionary measure," $252 million is being sought to build underground walls to prevent water from seeping into the terminal buildings and refueling tanks.
"The crucial part of the airport is inside the terminal's basement, and the entire airport stops functioning if water seeps in there," Hayashi said.
Officials say the sinkage is likely to slow and will not compromise the airport's future. But there is increasing concern about construction of a second runway, on a new island further offshore, that is planned to open in 2007, in time for the 2008 Summer Olympics, which Osaka hopes to host. It also has raised questions about plans for two new airports in central and western Japan.
Officials say they have learned enough to avoid the sinkage problems when they build the new runway. But many Osaka residents, obliged to cover the cost overruns, aren't so sure.
"It's unfair our tax money is eaten away because of miscalculation," said Yoshiyuki Adachi, who was recently at the airport with his 3-year-old son.