On July 29, 2025, a magnitude 8.8 earthquake shook the Kamchatka Peninsula in Russia, generating a tsunami that propagated across the Pacific. Thanks to a timely pass by the SWOT satellite, researchers captured detailed data just 70 minutes after the event, obtaining an exceptional view of the tsunami's birth with remarkable accuracy.
Until now, tsunami monitoring relied mainly on DART buoys, which measure changes in pressure on the ocean floor. Although these instruments are useful for warnings, they provide localized information, limiting the understanding of the full wave structure. Furthermore, traditional models, like the long-wave model, often ignore aspects such as dispersive waves.
About an hour after the earthquake, SWOT captured the tsunami's wave field near Kamchatka, visible as red-blue measurement strips. These data allowed the simulation of the initial sea surface elevation and the reproduction of the surrounding wave field.
Credit: Bjarke Nilsson In contrast, SWOT offers a two-dimensional view of the ocean surface with centimeter-level precision. This capability allows the observation of the direction, spacing, and curvature of waves, including dispersive waves that were previously difficult to detect. According to the researchers, these images provide key information for a more complete characterization of tsunamis.
Faced with the limitations of classical models, the research team adopted a Boussinesq-type model to faithfully reproduce the SWOT observations. This approach made it possible to locate the origin of the tsunami within less than 10 kilometers (about 6.2 miles) of the ocean trench, achieving unprecedented accuracy. The dispersive waves, thus integrated, reveal details about the seismic source, significantly improving event modeling.
These discoveries pave the way for more accurate tsunami models. By combining satellite data with existing warning systems, it becomes possible to improve forecasts of wave height and their timing.