Waves of a tsunami hit in Natori, Miyagi Prefecture, Japan, last year. - Kyodo News, via Associated Press
KUROSHIO, Japan — The simulations shocked this sleepy community on the tip of Japan’s Shikoku island: a huge undersea quake could bring a tsunami as high as 112 feet here, a government-appointed expert panel said. The waves could arrive in minutes and engulf most of the town, swallowing up even the foothills that the residents had counted on for high ground.
“We’d never make it if such big waves came,” said Hachiro Okumoto, 70, a fisherman who has worked off the Kuroshio coast for half a century. “It would be a wall of water. It would block out the sun.”
Just a year after a tsunami destroyed much of Japan’s northern Pacific coast, an updated hazard map detailing the damage that could be unleashed by another quake of a similar magnitude has been met with alarm across the country.
The new simulations take into account the lessons learned from the 9.0-magnitude temblor that hit off the Japanese archipelago in March last year. The fault lines in this seismically volatile region could cause far-bigger earthquakes than previously thought possible, spawning tsunamis affecting far wider — and far more populous — areas than the one last year.
According to the new study, released by the panel of seismic experts a week and a half ago, a 9.1-magnitude quake in the Nankai Trough off Japan would trigger intense shaking and tsunamis along a wide stretch of Japan from Tokyo southward, an area many times longer than the Tohoku coastline that was ravaged last year.
According to the report, Niijima, an island 100 miles south of Tokyo, could be hit by waves reaching 97 feet, overrunning most of the island’s inhabited areas. Shimoda, a popular beach town about 110 miles southwest of the capital, could be swamped by waves reaching 83 feet.
Waves of over 30 feet could hit the historic capital of Kamakura, the industrial hub of Toyohashi, the dolphin-hunting town of Taiji and almost 50 other coastal cities and towns. Even central Tokyo could be hit by 10-foot waves, the study says.
About 70 percent of Japan’s population, and much of Japan’s industry and infrastructure, is concentrated along the Pacific coast, from the top of the main island of Honshu south to Shikoku and Kyushu islands.
The doomsday possibilities have worsened the frayed nerves of a country still uneasy after the 2011 disaster, which killed almost 20,000 people along the Pacific coast and set off multiple meltdowns at a nuclear power plant 160 miles north of Tokyo.
“After a disaster of such unprecedented scale, there was a need to update our thinking to include previously unforeseen possibilities,” said Fumihiko Imamura, a tsunami specialist at Tohoku University in northeastern Japan and a member of the panel that drafted the hazard map. “These simulations highlight the need for communities to bolster their evacuation plans.”
Nowhere has the anxiety been more pronounced than Kuroshio, a popular surfing spot and whale-watching town of 13,000 on the southwest corner of Shikoku, Japan’s smallest main island. At an emergency local council meeting on March 31, when the simulations were announced, Mayor Katsuya Onishi declared the future of the town “in peril.”
The scale of the possible tsunami trumps all previous notions of the risks facing the town. Deadly tsunamis have been rare here; the last few waves to reach Kuroshio, including one in 1946, did little damage.
Town officials are not entirely blind to the risks of sitting on a shoreline facing one of the world’s most active seismic rupture zones. Two years ago, they built a tsunami tower for residents to flee to, but it is only about 40 feet above sea level.
And after the tsunami last year, Kuroshio decided to modify plans for a new town hall, moving it farther up into the foothills. But even the new town hall would be just 72 feet above sea level.
“Only a fool would run to the tower now,” said Yukihide Kubota, 60, a small electronics shop owner who has lived his whole life just minutes from the shore. His Plan B — to shinny up the century-old pine tree in his back yard — was also now defunct, he said.
“I’d make for those hills,” he said, pointing to high ground that he said would take at least 15 minutes to reach by car, “and pray we can somehow outrun the waves.”
But his 25-year-old son eventually plans to move away from the shore, Mr. Kubota said. “After such a big tsunami,” he said, “maybe this whole area ends up under the sea. Maybe I am the last of my family to ever live here.”
Few places in Kuroshio clear the 112-foot mark, and Mr. Kubota’s sentiment is one repeated across the town. A day care center, an elementary school and a high school that had been designated as tsunami evacuation areas all lie well below 65 feet. So do all of Kuroshio’s medical clinics.
About four-fifths of the population inhabits low-lying areas that would be inundated by a large tsunami, according to the town. On Monday, about 130 coastal residents took part in a tsunami drill, climbing a hill about 80 feet high.
“This was supposed to be a safety area,” said Miwa Ninomiya, who heads a day care center with about 130 children. “If such a big tsunami comes, we will simply have to take the children on our backs and run for our lives.”
There is talk of relocating parts of the city to higher ground, or even of building airtight underground bunkers fitted with oxygen tanks and electric generators. But the thrust of the town’s current contingency plans is simply: be prepared to flee for higher ground.
Still, in a town with a declining and aging population, many would simply be unable to run quickly enough or to scramble up the foothills to safety, local officials worry. More than half of the victims of the tsunami last year were over 65.
Some townspeople are angry at the seemingly far-fetched simulations.
Some experts argue that predicting earthquakes is a far-from-scientific pursuit. Those who put together the latest hazard maps emphasize that the study does not predict an imminent large quake, and they stop short of estimating when one might hit.
In a corner of Kuroshio, an epitaph engraved in moss-covered granite serves as a memory of the last deadly tsunami to reach its shores, in 1854: “The farms and rice paddies became the sea. Let this be a warning for the next 100 years.”
- The New York Times
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