The impact of the tsunami on Minamisoma shown on 12 March. Credit: Digital Globe.
Eduardo Kausel is a professor of civil and environmental engineering at MIT.
As anyone who has seen the astonishing video footage of Tokyo skyscrapers swaying from side to side can attest, Japan is at the very forefront of the science of earthquake-proofing buildings. But given that most of the damage and destruction was done by the subsequent tsunami, not the earthquake, Japan is now faced with some important decisions.
Unlike Haiti, where thousands of people lost their lives in an earthquake early last year, Japan is a wealthy, sophisticated, and, perhaps most importantly, supremely well-organized modern nation. Rebuilding the towns and villages that have been damaged will be a tremendous exercise, the cost of which may well run into trillions of yen, but it is exactly the sort of civil engineering challenge that the Japanese will rise to. They will honor their dead and dust themselves off, and then the engineers will be sent in. Order will be brought to chaos, and I suspect it will be done quickly.
In the short term, damage assessment is likely to focus on two very different areas. First, structural engineers will be sent into modern earthquake-proofed buildings to examine the impact of the quake on the quake-proofing technology.
Just because a building is still standing doesn’t mean it hasn’t been damaged. While certain elements of quake-proofing (such as diagonal bracing) are designed to help the building move with the shifting ground, others (such as viscous dampers and shock absorbers) are designed to dissipate the earthquake’s energy. Damaged components will have to be replaced or, where the associated cost is too high, the building will need to be demolished. But that’s not a failure for quake-proofing. It’s a success: the building withstood the quake. For decades, that’s been the primary aim of quake-proofing—preserving human life and avoiding extensive damage during moderate but oft-recurring earthquakes, not constructing buildings that can survive unscathed even after a monster earthquake like this one.
The second area of damage assessment will be on the devastation wrought by the tsunami. Traditional, low-lying Japanese houses and buildings are mostly of low cost and quick to build, as befits a country that has lived with the threat of earthquakes for centuries. So theoretically it’s quite possible that many of the worst-hit areas could be rebuilt quickly. But before they are, the huge loss of life has to be taken into consideration.
This, after all, is the second devastating tsunami to hit the Far East in just over six years. Isn’t it time some lessons were learned? Shouldn’t schools and hospitals, for instance, now be rebuilt on higher ground? Shouldn’t entire coastal settlements be relocated further inland? These are the sort of questions the country’s civil engineers and infrastructure planners will be asking themselves as the rebuilding process gets underway.
With earthquakes such a fact of life in Japan, and the relatively shallow seas of northeastern Japan making the area particularly vulnerable to a tsunami, I hope the Japanese authorities act responsibly, and if necessary, relocate and redesign entire towns and villages, as well as future nuclear power stations. We know now that you can’t tsunami-proof a town or building; all you can do is move it out of the way.
But I wouldn’t bet on the authorities taking the right action. Time and again, all over the world, settlements that have been destroyed by a natural disaster are simply rebuilt in exactly the same place. That’s what happened in the Thai beach resorts devastated by the 2004 tsunami, and it’s also what happens on an almost routine basis in certain parts of the United States. Low-lying properties on the Gulf of Mexico and the Eastern Seaboard are destroyed by seasonal hurricanes and rebuilt over and over again, often with the help of financial incentives from the U.S. government.
Whatever the choices made, it will become a matter of national pride that this part of Japan is rebuilt, not necessarily bigger than before, but certainly better. New buildings of three, four, and five stories will have appropriate levels of quake-proofing technology incorporated in their design, as will new bridges, stations, and elevated roads. And around all this new infrastructure, traditional, timber-framed houses will rise from the muddy wastes. Slowly, life will return to something resembling normality. And, if the rebuilding is done almost exclusively by Japanese companies, this has the potential to fuel a domestic construction boom that could save the country from the economic doldrums it’s been stuck in for over a quarter of a century.
There are important lessons to be learned here, for other parts of Japan and for coastal cities located in active earthquakes zones around the world. I hope authorities on the other side of the Pacific, in San Francisco, Los Angeles, and Seattle, will revise their own plans for “the big one” accordingly and include preparations for a tsunami. Because if Japan’s devastating earthquake has taught us anything, it’s this: it’s not a matter of if it comes, but when.