Satellite Captures First High‑Resolution Swath of Pacific Tsunami After Magnitude 8.8 Quake

This summer, a magnitude 8.8 earthquake off the coast of Russia generated a Pacific‑wide tsunami with waves that reached as far as Hawaii. The tremor was one of the largest in modern records, prompting dramatic local reactions—reports included sea lions rushing into the water and medical staff struggling to maintain control during an operation when the shaking began.

Surface Water and Ocean Topography (SWOT), a new ocean‑observing satellite, recorded the event from space and captured the first high‑resolution, swath‑style track of a major subduction‑zone tsunami. Unlike previous satellites that trace only a narrow line, SWOT can observe a broad swath of the sea surface—up to about 120 kilometers wide—providing unprecedented detail on tsunami behavior across the open ocean.

Why This Matters

SWOT’s wide‑swath measurements complement point sensors such as DART buoys by showing the tsunami wavefront across a continuous area, not just at isolated locations. The satellite data revealed differences between the observed waves and some model predictions, exposing inaccuracies in existing forecasts and offering new information to refine tsunami hazard assessments.

“I think of SWOT data as a new pair of glasses. Before, with DARTs we could only see the tsunami at specific points in the vastness of the ocean. There have been other satellites before, but they only see a thin line across a tsunami in the best‑case scenario. Now, with SWOT, we can capture a swath up to about 120 kilometers wide, with unprecedented high‑resolution data of the sea surface.” — Angel Ruiz‑Angulo, University of Iceland

Researchers led by Ruiz‑Angulo used the SWOT record in a landmark study examining the hazard implications of short recurrence intervals of great earthquakes, showing how differences in rupture style can govern tsunami severity. Although this particular tsunami caused relatively limited damage, the detailed spaceborne observations represent a major advance for tsunami science and early warning.

Looking ahead: The research team plans to continue using SWOT to observe future tsunamis and integrate those observations into models and warning systems, with the goal of improving coastal preparedness and reducing risk to vulnerable communities.