A satellite created to track the height of the ocean’s surface demonstrated its capabilities when a powerful earthquake occurred on the Kamchatka Peninsula in late July, generating a tsunami across the Pacific. According to researchers stating in The Seismic Record, the Surface Water Ocean Topography (SWOT) satellite produced the initial comprehensive space-based view of a significant tsunami created by a subduction zone event. Its observations disclosed a surprisingly complex pattern of waves spreading and interacting across the basin, offering scientists the latest insight into how tsunamis travel and the challenges they pose to coastal areas.
Combining Satellite and Buoy Data
To better comprehend the magnitude 8.8 earthquake on 29 July, Angel Ruiz-Angulo of the University of Iceland and his team merged SWOT measurements with details from DART (Deep-ocean Assessment and Reporting of Tsunamis) buoys that lay in the tsunami’s path. This quake, situated in the Kuril-Kamchatka subduction zone, ranks as the sixth largest recorded globally since 1900.“I think of SWOT data as a new pair of glasses,” stated Ruiz-Angulo. “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.”
SWOT: A New Era in Ocean Monitoring
Introduced in December 2022 through a partnership between NASA and the French space agency Centre National d’Etudes Spatiales, SWOT was established to offer the initial global assessment of Earth’s surface water. Ruiz-Angulo mentioned that he and co-author Charly de Marez “had been analyzing SWOT data for over two years understanding different processes in the ocean like small eddies, never imagining that we would be fortunate enough to capture a tsunami.”Rethinking Tsunami Behavior
As the wavelength of a huge tsunami is longer than the ocean’s depth, these waves are often regarded as “non-dispersive,” which means they mostly sustain a single wave shape as they travel. “The SWOT data for this event has challenged the idea of big tsunamis being non-dispersive,” Ruiz-Angulo describes. Numerical models that included for wave dispersion aligned more closely with SWOT observations of the Kamchatka tsunami.“The main impact that this observation has for tsunami modelers is that we are missing something in the models we used to run,” Ruiz-Angulo cited. “This ‘extra’ variability could represent that the main wave could be modulated by the trailing waves as it approaches some coast. We would need to quantify this excess of dispersive energy and evaluate if it has an impact that was not considered before.”
Revisiting Earlier Models
The researchers mentioned that the tsunami forecasted by earlier seismic and land deformation models did not match exactly with DART tide gauge readings. Using DART data in an analysis called inversion, they determined that the Kamchatka earthquake rupture expanded further south and measured 400 kilometers, longer than the 300 kilometers forecasted by previous models.“Ever since the 2011 magnitude 9.0 Tohoku-oki earthquake in Japan, we realized that the tsunami data had really valuable information for constraining shallow slip,” stated study co-author Diego Melgar. He highlighted the significance of combining seismic and oceanographic details for accurate tsunami modeling.
“With some luck, maybe one day results like ours can be used to justify why these satellite observations are needed for real or near-real time forecasting,” Ruiz-Angulo mentioned, emphasizing SWOT’s potential to transform tsunami forecasting and ocean monitoring.
Historical Context
One of the largest Pacific tsunamis recorded happened in 1952 in the same Kuril–Kamchatka subduction zone, which resulted in the creation of an international alert system. This system has a major role in providing Pacific wide warnings during the July 2025 tsunami event.FAQs:
1. What triggered the Pacific tsunami?A magnitude 8.8 earthquake off the Kamchatka Peninsula triggered the tsunami. It spread across the Pacific Ocean, impacting coastal areas.
2. What makes the SWOT satellite important?
SWOT spots high resolution, wide region views of the ocean surface. This enables scientists to see tsunami wave patterns that were previously impossible to observe.
