Japan's Underground Frontier

By Seiichi Kanise

Underground. The word brings many unsavory adjectives to mind: dark, dank, clandestine, illegal. But in Japan the "underground" is becoming the new frontier and the best hope for solving one of the country's most intractable problems. With a population nearly half the size of the U.S.'s squeezed into an area no bigger than Montana, Japan has virtually no room left in its teeming cities. Developers have built towering skyscrapers and even artificial islands in the sea, but the space crunch keeps getting worse. Now some of Japan's largest construction companies think they have an answer: huge developments beneath the earth's surface where millions of people could work, shop and, perhaps eventually, make their homes. "An underground city is no longer a dream. We expect it to actually materialize in the early part of the next century," says Tetsuya Hanamura, the chief of Taisei Corp.'s proposed development.

Taisei calls its project Alice City, after Lewis Carroll's heroine who went underground by way of a rabbit hole. The company, which has drawn up elaborate plans, envisions two huge concrete "infrastructure" cylinders, each 197 ft. tall and with a diameter of 262 ft., that would be built as much as 500 ft. belowground. They would house facilities for power generation, air conditioning and waste processing. Each cylinder would be connected by passages to a series of spheres, which would accommodate stores, theaters, sports facilities, offices and hotels. Taisei's initial $4.2 billion design could support 100,000 people.

Even more ambitious is the Urban Geo Grid proposed by Shimizu Corp. It would be an immense network of subterranean atriums connected by tunnels and filled with such facilities as offices, gymnasiums, libraries, exhibition halls and public baths. The project would be built 164 ft. below the ground, sprawl across 485 sq. mi. and accommodate 500,000 people. Not only would temperature and humidity be controlled, say the planners, but real sunlight would be reflected in through vents from the surface. Estimated cost: $80.2 billion.

Neither project has received an official go-ahead, but the Japanese government has set up task forces in several ministries to think about underground cities. Says Nobuhiko Sato, a high-ranking planner at the Construction Ministry: "The time has come to consider urban planning from the vertical viewpoint. Underground development has a great and realistic potential for alleviating congestion."

| Japanese companies say they have the technology to build extensive subterranean projects without disturbing the people aboveground. The Tokyo Electric company already has a high-voltage power station right below a Buddhist temple. Engineers are confident that they can create enormous underground structures with little danger of cave-ins. They point to such construction breakthroughs as the 33.5-mile-long Seikan Tunnel, the world's longest underwater corridor, which connects Japan's main island of Honshu with Hokkaido to the north.

Nonetheless, serious questions remain. Though Japanese cities already have underground shopping malls and parking garages, their depth and size have been strictly limited by law. The reason: a devastating fire in an underground shopping mall in Shizuoka that killed 15 people in 1980. Subterranean structures are resistant to earthquakes and water leaks but generally vulnerable to fire and smoke. Architects believe they can beat the problem with sophisticated sensor systems to warn of fires and temporary shelters in which the inside air pressure is kept slightly higher than normal to repel smoke.

The biggest obstacle could be the psychological barrier to living away from the sun and sky. Critics see the potential for mass claustrophobia. For that reason, planners foresee few underground housing projects, at least initially. The idea is to move offices and stores beneath the surface to free up the land above for residential building. People would become vertical commuters, going down a huge elevator shaft to work.

The supporters of underground living believe it can be made comfortable with spacious, well-lighted enclosures and liberal use of plants that grow indoors. "Creating an illusion is not so difficult as one might think," says Shoji Takahashi, chief engineer for Asahi Television, which built a studio 66 ft. below Tokyo's fashionable Roppongi district. "When it's raining up there, we use a special shower to create a rainy night in the underground studio too."