NAGASAKI - Some historic buildings on Nagasaki's Hashima island, also known as Gunkanjima, which once thrived on coal mining, have been deemed by experts as in danger of collapsing, according to city officials.
Gunkanjima, meaning "battleship island" after its appearance, is one of a group of legacy sites remaining from the Meiji-era (1868-1912) industrial revolution that the government wants to add to UNESCO's World Heritage list. Four apartment buildings, including the nation's oldest high-rise reinforced-concrete apartment, and part of another building are regarded by the Architectural Institute of Japan as "seriously damaged" or in imminent danger of collapse, the officials said.
According to the Cultural Affairs Agency, experts have yet to devise techniques to repair reinforced concrete when it has seriously deteriorated. Researchers, therefore, will hold an international conference in the city in June next year, hoping to come up with a method to preserve and restore the buildings.
The 6.3-hectare island, located about 19 kilometers from central Nagasaki, prospered on seabed coal mining. In 1960, about 5,300 people lived on the island, with about 30 reinforced concrete buildings, including apartments, a school and a hospital, built from the Taisho era (1912-1926) to the Showa era (1926-1989). After the mine was closed in 1974, the island became deserted. The buildings have been abandoned for 40 years, exposed to high tides, wind and rain. After a ban on entry to the island was lifted in April 2009, it became popular with tourists. The number of visitors topped 500,000 as of spring, but approaching the buildings is prohibited.
After a request by Nagasaki city government, the institute conducted research on the buildings from 2011 to 2013. The institute inspected 12 buildings for signs of deterioration, including Building No. 30 - the nation's oldest high-rise apartment, comprising seven floors, which was built in 1916. As a result, four buildings were determined to be seriously damaged. In estimating the number of years remaining before the buildings collapsed, Building No. 30 was calculated at minus five years, meaning it should have collapsed five years before 2012, when it was inspected.
An international conference will be held by the Japan Concrete Institute, which about 150 researchers including experts from Western countries are scheduled to attend. Takafumi Noguchi, a professor at the University of Tokyo who studies building materials, says the worth of the island will be greatly reduced if its buildings collapse. He is head of the institute's research group and chairman of the international conference.
"We hope we can gather the latest knowledge and experience of each member for preservation and restoration [of the buildings]," Noguchi said.
UNESCO list plans
The legacies of the Meiji era industrial revolution, which consist of 23 sites in eight prefectures, including Gunkanjima, are expected to be registered as World Cultural Heritage sites next year. UNESCO's advisory body, the International Council on Monuments and Sites (ICOMOS), is planning to advise UNESCO's World Heritage Committee on registrations around May next year.
The Nagasaki city government is currently working toward establishing a programme to repair and utilize the Gunkanjima buildings, the main focus of which is limited to preserving the buildings at several major residential areas. The city government excludes Building No. 30 from preservation efforts as its life cannot be prolonged with current technology, according to the local government.
"As a general rule, historic sites should be preserved as they are. But there are some buildings that cannot be preserved for technical reasons," a Cultural Affairs Agency official said. "If a new technology is developed, we want to use it."