Stanford scientists' computer models help predict tsunami risk
By By Steven Fyffe | 14 Dec 2011
When a magnitude 9.0 earthquake struck off the coast of Japan in March, it triggered a tsunami that killed more than 20,000 people and destroyed entire cities. It was the largest earthquake ever recorded in Japan, and the scale of the disaster stunned even geophysicists who specialise in earthquake science.
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| Scientists were surprised by the size and destructive force of the tsunami that followed the March 2010 earthquake off the coast of Japan. (Photo: MC3 Dylan McCord / US Navy) |
"In this earthquake it was really surprising that we got such a large seafloor uplift and such a large tsunami," says Eric Dunham, assistant professor of geophysics.
"Before this earthquake, before we had these detailed measurements, it was thought that this upper part of the fault would not slip in one of these large earthquakes.The extreme amounts of slip in the upper part of the fault led to a large amount of uplift in the seafloor, and then that uplifted the column of water that sloshed back down and created this large tsunami," Dunham explains.
Measurements from the quake zone show that the fault slipped about 20 meters, and the seafloor lifted up about 7 meters.
"This is essentially a third of a football field. The plate was displaced horizontally, and the seafloor lifted up about the height of a two-story building," said Jeremy Kozdon, a post-doctoral research fellow who has been working with Dunham to create computational models to pinpoint the cause of the devastating tsunami.
"It was expected that there would be large earthquakes in this region, but it wasn't expected that there would be a magnitude 9.0. And it wasn't expected that there would be a large tsunami, or at least a tsunami of this size."