By many measures, the magnitude 9.0 earthquake that shook Japan a year ago was a record-breaker. It was the largest quake in the country's written history, the trigger for the worst nuclear accident in 25 years and the costliest natural disaster ever.
Amid such superlatives, it's easy to forget one more: During the Tohoku-oki quake, the seafloor off Japan's coast wrenched itself farther apart than scientists had ever measured along any seafloor. In places, chunks of ground slipped horizontally past their neighbors by more than 50 meters and vertically by 10 meters.
"The earthquake was a scofflaw," says Emile Okal, a geophysicist at Northwestern University in Evanston, Ill. "It violated the scaling laws we're used to."
That deviant behavior is what made the quake so deadly, by producing a monster tsunami. (sciencenews.org)
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