SWOT Satellite Measures Pacific Tsunami
The U.S.-French SWOT (Surface Water and Ocean Topography) satellite captured the leading edge of a tsunami wave that rolled through the Pacific Ocean on July 30, 2025 (11:25 a.m. local time), in the wake of a magnitude 8.8 earthquake that struck Russia's Kamchatka Peninsula. The satellite captured the data about 70 minutes after the earthquake struck.
The SWOT sea level measurements, shown in the highlighted swath from the satellite's ground track, is plotted against a tsunami forecast model from the National Oceanic and Atmospheric Administration (NOAA) Center for Tsunami Research in the background. A red star marks the location of the earthquake.
The measurements show a wave height exceeding 1.5 feet (45 centimeters) as well as a look at the shape and direction of travel of the leading edge of the wave (indicated in red). Researchers noted that while the wave height might seem small, tsunamis extend from the seafloor to the ocean surface. A seemingly small wave in the open ocean can become much larger in shallower coastal waters.
The SWOT satellite was jointly developed by NASA and the French space agency CNES (Centre National d'Études Spatiales), with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA JPL, managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. The Doppler Orbitography and Radioposition Integrated by Satellite system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
To learn more about SWOT, visit: https://swot.jpl.nasa.gov/