Izumisano (Japan) - Kansai Airport in the southwest of Japan is one of the most expensive and busiest airports in the world. But the airport in Izumisano has a huge problem: it is too heavy! Built several kilometers off the coast on an artificial island in the sea, it is sinking further into the water every year. Is a super-GAU imminent?

More than 30 million passengers visit "Kansai Kokusai Kūkō" every year! In comparison: BER had 25.5 million passengers in 2024, while the world's busiest airport (Atlanta International Airport) had more than 90 million.

But the construction costs of the airport near the mega-city of Osaka are even more extreme. Although it was completed in 1994, it is said to have cost around 19 billion dollars (BER cost around 7.3 billion, despite all the problems and inflation)!

Just 31 years later, the airport is sinking into the sea at an "alarming rate", as reported by the Essential Japan portal.

Although it holds several world records and great attention was paid to earthquake prevention during its construction, all the possible complications of building on an artificial island were apparently not considered.

A typhoon already caused severe flooding in 2018. This risk increases every year.

The engineers had expected a certain amount of subsidence, but not 11.5 meters! They had actually assumed eight meters in 50 years.

In the past, tens of millions have already been invested in securing the ground, and the subsidence rate has been reduced to around seven centimetres per year.

But the danger remains. In order to reduce the risk of flooding and faster subsidence, Kansai Airport and its subsoil are currently being renovated at a cost of well over (the equivalent of) 500 million euros.