On March 11, 2011, a magnitude 9.1 megathrust earthquake struck off the coast of Japan. Violent tremors lasted for about six minutes, shifting the main island of Honshu up to eight feet east and triggering a massive tsunami that reached heights of up to 133 feet.
The earthquake and tsunami, which traveled up to six miles inland and then washed back out to sea, resulted in over 18,000 dead, including several thousand victims who were never recovered. Damage has been estimated at over $220 billion, ranking it as the costliest natural disaster in world history.
As the Tohoku tsunami raced across the Pacific basin, a real-time tsunami flooding forecast model developed by researchers at the Pacific Marine Environmental Laboratory faced its first operational test at NOAA's Tsunami Warning Centers.
"Tsunami detection and forecasting systems had been in development at PMEL since before the 2004 Indian Ocean tsunami," said PMEL director Michelle McClure. "This tragedy underscored the urgency and importance of rapidly identifying and predicting tsunami events locally and globally."
The tsunami inundation forecast produced on March 11, 2011, marked the first time such a forecast was generated in real time before the tsunami reached its predicted locations in Hawaii and along the U.S. West Coast, said Vasily Titov, senior tsunami modeler with NOAA's Center for Tsunami Research. "This event successfully confirmed the design capabilities of the system, which was undergoing testing operations at the time. The forecast accuracy, especially for inundation, was very good."
Today, PMEL's tsunami inundation forecast is fully operational at NOAA Tsunami Warning Centers. This system employs over 90 high-resolution models to deliver coastal tsunami forecasts, including predictions for tsunami amplitudes, inundation levels, and dangerous currents, covering all U.S. coastal population centers that are susceptible to tsunamis.
In 2011, 50 real-time tsunami monitoring DART buoys were deployed by the U.S. and international partners. Today, over 70 DART systems are deployed by the U.S. and international partners. New, 4th generation DART Buoys can detect tsunamis earlier and provide better data for forecast models. Several tsunami detection cable systems are in use by the U.S., Japan and Canada.
These innovations have led to forecasts that are 10 times faster—and with better accuracy.
The system was most recently tested during the 2025 Kamchatka tsunami that produced coastal flooding across the Pacific. This 8.8 magnitude megathrust event off the eastern coast of Russia's Kamchatka Peninsula was the most powerful seismic event globally since the 2011 Tohoku earthquake and tied for the sixth-strongest earthquake ever recorded.
Tsunami warnings were issued for Russia, Japan, Hawaii, and the U.S. West Coast. Over 1.9 million people were evacuated in Japan as a precaution. No direct deaths from the shaking were reported; however, one indirect fatality occurred during evacuations in Japan.
In Seattle, scientists continue to refine the next-generation forecast system, termed the Common Analytic System (CAS), which will produce faster, more accurate, actionable forecast systems for the National Weather Service's two Tsunami Warning Centers. The CAS will enable the two warning centers to collaborate seamlessly under a Common Operating Picture and produce a unified forecast during a tsunami event, and for each center to seamlessly back up the other in case of an outage.
