Tsunami

Walter Craig has done some mathematical modeling of tsunamis, and his figures dispel some myths.

Among his findings, the first crest in a series of tsunami waves is not always the biggest, and an extraordinarily low tide only precedes about half the tsunamis.

Another widely held belief about tsunamis that gets washed away with mathematical modelling is that the surge is always preceded by the tide going abnormally far out. "This only happens about half the time," explains Dr. Craig. "It depends on the wavelength and whether it's the trough or crest of the wave that reaches shore first. In half the cases it's the surge that arrives first."

Of course, that means if you see water draining away from the shore, you'd better get out of there fast.