Saturday's tsunami traveled 6,000 miles and hit California's beaches right on schedule — but waves were rarely as large as predicted, landing with a whimper rather than a wallop. In the first big test of a new Pacific Ocean tsunami system, the magnitude-8.8 Chilean earthquake showed that while scientists can anticipate the arrival time of waves, they struggle to forecast the precise size.
The system uses a series of seismic monitoring stations, sea level gauges, water pressure sensors and seabed measurements. Scientists then feed the data into computer models that calculate speed and direction. But the tsunami travels faster than the computers can calculate. So calculations must be simplified, introducing error. "It's very complicated, even with high-tech instruments and computer models," said U.S. Geological Survey geophysicist Eric Geist.
