NASA Satellite Captures Megatsunami, Scientists Reveal Surprising Facts

A NASA satellite has captured high-resolution images of a megatsunami triggered by a massive earthquake off the coast of Russia’s Kamchatka Peninsula in late July 2025. The tsunami, which propagated across the Pacific Ocean, was recorded in detail by the Surface Water Ocean Topography (SWOT) satellite, providing scientists with an unprecedented view. The findings were published in The Seismic Record journal, with researchers calling it the first high-resolution, wide-coverage observation of a major tsunami triggered by a subduction zone earthquake. The observations revealed a surprising fact: rather than moving as a simple wave, the tsunami displayed far more complex patterns, spreading, scattering, and interacting across a vast area of the Pacific Ocean. This discovery is expected to help scientists improve the accuracy of tsunami early warning systems and better understand the risks faced by coastal regions, including countries in the Pacific such as Indonesia. The tsunami was triggered by a magnitude 8.8 earthquake that struck the Kuril-Kamchatka subduction zone on 29 July 2025, an area where tectonic plates collide and one is forced beneath the other. The earthquake was recorded as the sixth largest in the world since 1900. To study the event, scientists combined data from the SWOT satellite with measurements from DART (Deep-ocean Assessment and Reporting of Tsunamis) buoys deployed across the Pacific Ocean, which are designed to detect minute changes in sea level and provide early warning information. Lead author Angel Ruiz-Angulo from the University of Iceland said the SWOT satellite provided a completely different perspective compared to previous observation methods. ‘I think of the SWOT data as a new pair of glasses,’ he said. Previously, with DART, researchers could only see the tsunami at specific points across the vast ocean. He explained that while other satellites existed before, even at their best they could only capture a thin line crossing the tsunami. ‘Now, with SWOT, we can capture an area up to 120 kilometres wide with unprecedented high-resolution sea surface data,’ he explained. SWOT was launched in December 2022 as a joint mission between NASA and the French space agency, Centre National d’Etudes Spatiales (CNES). Its primary goal is to conduct the first comprehensive global survey of Earth’s surface water, from rivers and lakes to ocean phenomena. Ruiz-Angulo noted that he and his colleague, Charly de Marez, spent more than two years analysing SWOT data to study various ocean processes such as small eddies and currents. One of the most surprising findings relates to the concept of wave dispersion. Scientists previously believed that large tsunamis were ‘non-dispersive’ waves, meaning that because their wavelength is much greater than the ocean depth, they were expected to maintain a relatively similar shape even when travelling thousands of kilometres.