Tsunamis start when an undersea earthquake triggers waves of up to 500 miles an hour -- in the deep ocean it's barely a ripple. In the shallows, close to land, the waves swell and that power can become a wall of water a hundred feet high or more.
The Japanese know that walls aren't the only answer. Far better, they say, to give people some warning, even if its only a few minutes so they can run for the hills. To make it possible, the Japanese are turning increasingly to what they do best - hi tech.
At regional tsunami centers, in fact, sophisticated computers analyze every earthquake so officials can raise the alarm before the roar of a tsunami comes to claim its next victims.
Reported by Barry Petersen
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