Japan rethinks tsunami safety
Structural engineer Kit Miyamoto was giving a speech in Japan on earthquake safety when this month’s record quake struck, giving him a front-row seat for the unfolding disaster and what steps might save lives next time.
“This disaster basically paralyzed the whole country,” said Miyamoto, president of West Sacramento-based Miyamoto International, standing amid the wreckage in this battered coastal city. “We can learn a lot of lessons for California.”
What worked, and what didn’t?
Although some of the lessons will take years to nail down, experts said some things stand out already. One problem, some said, was Japan’s overreliance on the massive sea walls that were favored by its politically powerful construction industry and that provided a false sense of security.
Photos: Japan’s earthquake, tsunami and nuclear crisis
More than 40% of Japan’s coast is lined with breakwaters, sea walls and other structures, according to the Japanese government. Although some say the damage could have been worse without them, many of the structures were overrun or even collapsed, including the 1.2-mile Kamaishi sea wall, the world’s largest, built at a cost of $1.5 billion.
“The cost-benefit ratio of these enormous investments needs to be reassessed,” said Antonios Pomonis, a disaster-prevention expert based in Greece, who studied the 1995 earthquake in the Japanese city of Kobe.
At the Fukushima nuclear reactor, few thought about ensuring that the power supply was secure, because few thought the 17-foot wall could be breached. But the diesel generators designed to cool the core and spent fuel rods during shutdown were on low ground and quickly flooded.
“The wave went higher than we predicted,” said Tatsuyuki Kumagai, an official at Miyako City Hall.
California has two coastal reactors — Diablo Canyon and San Onofre — near active faults, both protected by sea walls. Although its geology is less prone to local tsunamis, California is still considered vulnerable to distant and some locally generated tsunamis.
Japan’s tsunami warning system worked well, experts said, providing people with a 20- to 30-minute warning, which may have saved 100,000 or more lives. The U.S. lacks a comprehensive warning system, critics said.
Costas Synolakis, the director of USC’s Tsunami Research Center, said the Los Angeles coast needs an instrument that provides real-time data on tsunamis.
“It’s inexcusable we don’t have one,” he said.
But human complacency remains a problem, even here in Japan. There had been a magnitude 7.5 earthquake two days earlier that produced a barely perceptible tsunami, leading many to ignore the warnings March 11, analysts said.
Japan has a good training system and an annual disaster-awareness day, things Americans haven’t implemented particularly well, experts said.
“It has to be a continuous effort,” said Peter Sammonds, a professor with University College London. “It’s not glamorous, I am afraid.”
Shigeki Sakai, a civil engineering professor at Iwate University, said he started working five years ago with one Miyako neighborhood on a disaster plan, including new evacuation routes and regular drills.
“Of a population of 110, all but one survived,” Sakai said. “Training is extremely important.”
But even some of those who lost their homes in the quake weren’t sure they would go to the classes. Yumiko Tachibana, an evacuee at a shelter in Miyako, said she was aware of them but never went.
“Even after living through this, I don’t think I’d go to one,” she said. “I’m too busy.”
Even a perfunctory trip to battered coastal communities shows that concrete and steel buildings held up relatively well, but most wooden buildings suffered wholesale destruction. Some say wood construction should be banned in tsunami areas, a move that could reduce the use of traditional Japanese architecture.
Others have called for a coastal buffer with no homes, probably unlikely given growing populations and pressure to develop coastline property.
“It may be rude to say this when people are missing, but I don’t think humans should live so close to the ocean,” said Kimio Onodera, a teacher of disabled children from Kesennuma, who lost friends in the tsunami. “They should live in high places.”
The destruction will no doubt lead to new building codes and altered city planning, giving battered communities a chance to start anew. Safeguarding power, water, fuel and telephone “lifelines” after a disaster will also probably become a priority.
Shoichi Sato, deputy mayor of Yamada, stood in City Hall overlooking the vast wasteland. “This is a turning point to change, start over,” he said. “We really need to question some basic assumptions.”
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