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News18
10-07-2025
- Climate
- News18
Japan's Kansai Airport Is Sinking Beneath Bay, Continues To Inch Lower Each Year: Report
Last Updated: Japan's Kansai International Airport has sunk over 17 metres since construction, more than initially expected, due to the soft clay foundation, a report has claimed. Japan's Kansai International Airport (KIX), built on a man-made island in Osaka Bay, is sinking. According to the South China Morning Post, while the airport has grown into a major hub for both domestic and international flights, it has already sunk into the clay layers beneath the bay more than engineers initially expected, and it continues to inch lower every year. The report quoted operator Kansai Airports and stated that the surface of the airport's first island is today about 3.84 metres (12.6 feet) lower than when it opened in 1994. Since landfill began for its construction, the airport has experienced an average settlement of 13.66 metres (45 inches), the report claimed. The operator is keen to point out that some 'settling" of the surface level was always expected. The average subsidence measured just 6cm (2.4 inches) across 17 points on the artificial island last year, according to the latest data released in December. The situation is somewhat worse at the second island, where the surface has fallen by 17.47 metres (57.3 feet) since the commencement of landfill work, and the average subsidence at 54 measurement points last year was 21cm (8.3 inches), according to the report. More than US$150 million has been spent on raising the sea walls surrounding the islands, but some engineers still predict that in the next 30 years, sections of the elevated airfield may be at sea level. The islands were constructed atop a 20-metre (65.6-foot) thick layer of alluvial clay, which acted like a sponge. The report also suggested that despite installing 2.2 million vertical pipe drains that were meant to solidify the clay and limit contraction, the weight of the landfill, including more than 200 million cubic metres (7.6 billion cubic feet) of debris and 48,000 tetrapods, has squeezed the clay more than anticipated. The challenges facing the airport became apparent in September 2018, when it had to be entirely shut down after being flooded by storm surges caused by Typhoon Jebi. The strongest typhoon to hit Japan in a quarter of a century caused US$13 billion in damage and led to 21 deaths across the Pacific, it mentioned. The report attributed to a statement on the operator's website, and stated that the rate of subsidence is lessening and it continues to monitor the foundations of the airport, including accumulating data on subsidence and seeking the advice of academics. Hiroo Ichikawa, a professor emeritus of urban planning and policy at Meiji University, said the sinking of the islands remained within acceptable levels and that the entire project had been a valuable learning experience for other similar man-made island plans. In the past, Japan's Kansai International Airport (KIX) has won international awards for its architectural design, efficiency and staff, and was recognised last year as the best airport in the world for baggage delivery after not mislaying a single item of luggage for a decade. Made up of two islands, one covering 510 hectares (1,260 acres) and the second over 1,055 hectares, the airport was built to ease overcrowding at the nearby Osaka International Airport and welcomed its first passenger flight in September 1994. view comments First Published: July 10, 2025, 13:10 IST Disclaimer: Comments reflect users' views, not News18's. Please keep discussions respectful and constructive. Abusive, defamatory, or illegal comments will be removed. News18 may disable any comment at its discretion. By posting, you agree to our Terms of Use and Privacy Policy.
Time of India
09-07-2025
- General
- Time of India
Japan's Kansai International Airport is sinking into the ocean; know what went wrong
Japan's Kansai International Airport is sinking Kansai International Airport (KIX) in Japan has long been considered an engineering marvel. Built entirely on an artificial island in Osaka Bay, it serves as a major aviation hub connecting over 30 million passengers each year to 91 cities across 25 countries. Since opening in 1994, KIX has grown into one of Asia's busiest and most critical international airports. But behind this success story lies a persistent and worsening issue: the entire airport is sinking into its soft clay foundation. According to a report by The South China Morning Post, the original island has sunk about 12.5 feet since its opening. The second island added later during expansion, has already descended 57 feet since landfill work began. In just the last year alone, officials recorded 21 centimetres of sinking at 54 separate monitoring points on the newer island. These figures highlight a growing concern—not just about the engineering design, but also the future of this key transport hub as sea levels rise and extreme weather events become more frequent. Despite these challenges, the airport remains fully operational, and engineers are working constantly to manage and slow down the rate of subsidence. This article explores why Kansai is sinking, how engineers are responding, and what lessons Japan has learned from this ambitious project. Why Kansai Airport was built on water KIX was constructed on a man-made island 5 kilometres offshore to address land shortages in the Osaka region and reduce noise complaints from densely populated areas. The engineering plan involved creating a foundation on about 20 meters of soft alluvial clay, known for its compressibility and instability. To tackle this, engineers installed 2.2 million vertical pipe drains to speed up the soil consolidation process and used over 200 million cubic meters of landfill and 48,000 tetrapods to stabilize the site. Despite this effort, the clay base continues to compress under the airport's weight. As explained by Hiroo Ichikawa, professor emeritus of urban planning and policy at Meiji University, 'It is sinking by less than 10 centimetres a year now, but that is slowing and manageable.' (South China Morning Post, 2024) Why Typhoon Jebi was a wake-up call for Japan's sinking airport The airport's vulnerability was fully exposed in 2018 when Typhoon Jebi, the strongest storm to hit Japan in 25 years, brought massive flooding. As reported by The Guardian, a storm surge flooded the airport's basement-level disaster response centre and electric substation, leaving 5,000 travellers stranded without power or transport for more than 24 hours. A fuel tanker even collided with the bridge connecting the airport to the mainland, cutting off the only road access. This event not only disrupted operations but also led engineers to reevaluate key design elements—particularly the placement of critical systems underground in a facility prone to flooding and subsidence. Ongoing sinking of Kansai International Airport: Latest measurements and response According to data published in The Straits Times and The Nation Thailand (June 2024), the second island experienced 21 centimetres of sinking in a single year, while the original island continues to settle at about 4 inches (10 cm) per year. Though slower than before, the subsidence has not stopped. In response, over $150 million has been invested in upgrading the airport's seawalls and reinforcing infrastructure. Engineers have elevated key equipment, such as power systems and disaster response centres, above potential flood levels. The goal is not to stop the sinking—because that's impossible—but to manage it within safe limits, as emphasized by Professor Ichikawa. 'The effect of sinking was taken into consideration in the design,' he said. 'Engineers are constantly monitoring conditions at KIX and are working to limit the subsidence, but nothing is impossible and it really is just a question of cost.' (South China Morning Post, 2024) Lessons learned: A smarter airport in Nagoya Kansai's experience has helped shape future airport construction in Japan. When Chubu Centrair International Airport opened in 2005 near Nagoya, engineers applied key lessons from KIX—especially in choosing more stable ground and keeping essential systems above sea level. This has paid off. According to Skytrax, Chubu Centrair has been named the world's best regional airport for 11 consecutive years through 2025. The facility has experienced minimal subsidence and has proven far more resilient to climate risks and natural disasters. Also read | What is 'Naked Flying': The minimalist travel trend taking off around the world
Indian Express
19-06-2025
- Indian Express
Why Japan's most celebrated airport is slowly sinking into the sea
Japan's Kansai International Airport (KIX), celebrated for its architecture, efficiency and precision baggage handling, is now fighting a far less glamorous battle—against nature itself. Built on a sprawling man-made island in Osaka Bay, the engineering marvel is slowly but steadily sinking into the clay bed it stands on, raising urgent questions about its long-term future and the viability of such ambitious offshore infrastructure. Inaugurated in 1994, KIX was once touted as a triumph of Japanese engineering. It was envisioned as a solution to congestion at Osaka's older airport and has since become a bustling international hub, linking over 30 million passengers to 91 cities across 25 countries. But three decades later, gravity and geology are proving to be formidable foes. The airport's original island has sunk 12.5 feet since opening. The second island, added during expansion, has fared worse, descending a staggering 57 feet since landfill work began. Last year alone, 21 cm of subsidence was recorded at 54 points on this newer island, South China Morning Post reported. The operator, Kansai Airports, insists that a degree of settlement was always expected and that recent measurements show the rate of sinking is slowing. 'It is sinking by less than 10cm (4 inches) a year now, but that is slowing and manageable,' said Hiroo Ichikawa, professor emeritus of urban planning and policy at Meiji University, SCMP reported. He acknowledged that while some missteps were made—like building critical infrastructure underground, which proved disastrous during a typhoon—engineers are now better prepared. The vulnerability of the site was dramatically exposed in 2018 when Typhoon Jebi, the strongest storm to hit Japan in 25 years, forced the complete shutdown of KIX. A storm surge swamped the airport, cutting power, flooding the basement-level disaster response centre and electric substation, and leaving 5,000 people stranded without power for over 24 hours. The project, constructed atop 20 metres of soft alluvial clay, was always a gamble. Despite using 2.2 million vertical pipe drains and massive landfill (including 200 million cubic metres of debris and 48,000 tetrapods) to stabilise the ground, the clay has compressed more than predicted. Over $150 million has since been spent raising sea walls around the islands to counter the threat of encroaching water. But not all experts are raising the alarm. Ichikawa called the project a 'valuable learning experience' and said similar airports, like Chubu Centrair near Nagoya, have benefited from the lessons learned at KIX. Opened in 2005 and smaller in scale, Centrair has experienced significantly less subsidence and was named the world's best regional airport for the 11th consecutive year in 2025 by Skytrax. 'The effect of sinking was taken into consideration in the design,' Ichikawa noted, SCMP reported. 'Engineers are constantly monitoring conditions at KIX and are working to limit the subsidence, but nothing is impossible and it really is just a question of cost.'
