"It's the finest illustration of what we're going to experience, and I'm sure Japan is better prepared than we are," said John Vidale, director of the Pacific Northwest Seismic Network at the University of Washington. The Cascadia fault last ruptured in 1700, causing a magnitude 9 earthquake and a tsunami that may have been larger than the one that hit Japan. Major earthquakes on the Cascadia fault happen every 400 to 500 years, but new research suggests they might happen much more frequently.

The magnitude 8.9 Japan quake was preceded by a series of magnitude 7 foreshocks, which experts would be closely monitoring, according to Vidale. "We're extremely eager to see whether something was going on that may have offered warning had they learned how to read it appropriately."

According to some geologists, the quake on Thursday had a magnitude of 9.1. If that turns out to be right, the official figure may be amended upward.

Scientists from the National Oceanic and Atmospheric Administration in Seattle rushed to their offices Thursday night, immediately after the quake struck, to assist in forecasting where tsunami waves might travel.

According to Eddie Bernard, director of NOAA's Pacific Marine Environmental Laboratory, a network of tsunami warning buoys established following the 2004 Indian Ocean tsunami paid off handsomely.

The tsunami wave was detected by two buoys off the coast of Japan minutes after the earthquake. Modelers in Seattle were able to estimate the route of the wave and its anticipated impact on Hawaii and the United States West Coast using this knowledge.

According to Bernard, the quake's position and direction meant that much of the West Coast was spared serious damage.

"It's good fortune and a fantastic location," he explained. "The repercussions on the Washington coast may have been far severe if the earthquake had occurred someplace else."