NOAA Research models tsunamis to keep coastal communities safe

On Tuesday, July 29th, 2025, an 8.8 magnitude earthquake occurred off the Kamchatka Peninsula in Russia, triggering numerous tsunami alerts in Alaska, Hawaii, the U.S. west coast, and throughout the Pacific. At the NOAA Pacific Marine Environmental Laboratory (PMEL), a team of researchers in the NOAA Center for Tsunami Research (NCTR) work to improve tsunami warnings and preparedness by enhancing measurement technology, optimizing monitoring networks, improving the accuracy of forecast models, and improving the prediction of coastal impacts. Continue reading to learn about this critical research that keeps citizens safe from tsunami threats.

Constant monitoring: Collecting real-time data

The Deep-ocean Assessment and Reporting of Tsunamis (DART) is a real-time tsunami monitoring system, developed by PMEL, that is positioned at strategic locations throughout the ocean to play a critical role in tsunami forecasting. DART systems are some of the first data collection points, sending real-time information to NOAA Tsunami Warning Centers. DART systems use underwater sensors and surface buoys to observe unusual wave activity and sea surface levels that could indicate a tsunami. When the sensors detect these sea level anomalies, the system sends real-time data via satellite to warning centers. This information then helps scientists update forecasts that can be used to update and scale watches, warnings, or advisories that protect people in vulnerable areas.

Looking ahead: Preparing inundation maps

Scientists test how tsunamis form, move across the ocean, and flood coastal areas by inputting detailed maps of the shape of the land and seafloor into computer models. These models can then be used to see how far a tsunami will travel and what the water depth will be in flooded areas. Detailed maps of future tsunami flooding (inundation) are critical for planning the best options for evacuation routes in vulnerable coastal communities. This mapping supports NOAA’s TsunamiReady® Program and the UNESCO-IOC’s Tsunami Ready Recognition Programme (TRRP) that empower communities to be prepared and resilient to tsunamis. NCTR scientists create inundation maps by utilizing the Method of Splitting Tsunami (MOST) model to simulate tsunami generation, ocean propagation, and detailed flooding over land.

Ready when it happens: Producing a tsunami forecast

Timely and accurate tsunami forecasts are crucial for local officials to support tsunami evacuations. NOAA is improving tsunami forecasting using a system called Short-term Inundation Forecasting for Tsunamis (SIFT). This system uses a library of pre-computed scenarios based on likely undersea earthquakes. When an earthquake happens, SIFT quickly combines these pre-computed scenarios with actual ocean observations provided by the real-time data from DART sensors. Warning center scientists use this information to produce timely forecasts of tsunami arrival times, wave heights, and inundation areas. As more data become available, SIFT automatically updates forecasts for warning center scientists to keep coastal communities informed.

To learn more about the ways NOAA researches and forecasts tsunamis, visit the links below:

• Science Behind Tsunamis
• Tsunami Safety
• Current tsunami warning, advisories, watches, or threats
• NOAA PMEL’s tsunami video playlist on YouTube

Did you know that wave anomalies detected by DART systems can last for days after a tsunami event? Imagine you drop a rock in a bathtub. The initial ripples or "waves" caused by the rock dropping into the water will travel across the tub and then bounce back off the walls. When a tsunami occurs, initial waves ripple across the ocean and then can bounce back when they hit land. An example of this was during the 2004 Japan tsunami event, when sea level anomalies continued for two days after the initial tsunami warnings were released and reflections were detected that crossed the ocean basin. Keep in mind that strong currents dangerous to swimmers and boats can continue even after a tsunami alert is cancelled.