JAKARTA, Indonesia • At least 40 percent of Japan's 22,000-mile coastline is lined with concrete sea walls, breakwaters or other structures meant to protect the country against high waves, typhoons or even tsunamis. But the devastation from Friday's earthquake, and a final death toll predicted to exceed 10,000, could push Japan to redesign those walls — or reconsider its heavy reliance on them altogether.
The risks of dependence on sea walls is most evident in the crisis at the Daiichi and Daini nuclear power plants, both situated along the coast close to the earthquake zone. The tsunami that followed the quake washed over walls that were supposed to protect the plants.
Peter Yanev, one of the world's best-known consultants on designing nuclear plants to withstand earthquakes, pointed out that the plants' diesel generators were situated in a low spot on the assumption that the walls were high enough. That turned out to be a fatal miscalculation.
Critics have long argued that the construction of sea walls is a hubristic effort to control nature as well as the kind of wasteful public works project that successive Japanese governments used to reward politically connected companies. Supporters have said the sea walls increased the odds of survival in a quake-prone country.
In Kamaishi, 14-foot waves surmounted the sea wall — the world's largest, erected a few years ago in the city's harbor at a length of 1.2 miles and a cost of $1.5 billion — and eventually submerged the city center.
"This is going to force us to rethink our strategy," said Yoshiaki Kawata, a specialist on disaster management at Kansai University in Osaka and the director of a disaster prevention center in Kobe. "This kind of hardware just isn't effective."
Sea walls also tend to be built in areas that have suffered tsunamis, sometimes as a way to jump-start the area economy. But because sea walls cannot be constructed along all of a community's shoreline, they tend to be clustered along stretches that have been directly hit, leaving other areas exposed.