The SWOT (Surface Water and Ocean Topography) satellite captured the tsunami spawned by an 8.8 magnitude earthquake off the coast of Russia’s Kamchatka Peninsula on July 30, 11:25 a.m. local time. The satellite, a joint effort between NASA and the French space agency CNES (Centre National d’Études Spatiales), recorded the tsunami about 70 minutes after the earthquake struck.
Disturbances like an earthquake or underwater landslide trigger a tsunami when the event is large enough to displace the entire column of seawater from the ocean floor to the surface. This results in waves that ripple out from the disturbance much like dropping a pebble into a pond generates a series of waves.
“The power of SWOT’s broad, paintbrush-like strokes over the ocean is in providing crucial real-world validation, unlocking new physics, and marking a leap towards more accurate early warnings and safer futures,” said Nadya Vinogradova Shiffer, NASA Earth lead and SWOT program scientist at NASA Headquarters in Washington.
This visualization depicts the leading edge of the tsunami based on sea surface height data from SWOT looking from south to north, when the leading edge was more than 1.5 feet (45 centimeters) high, east of Japan in the Pacific Ocean.
Data from SWOT provided a multidimensional look at the leading edge of the tsunami wave triggered by the Kamchatka earthquake. The measurements included a wave height exceeding 1.5 feet (45 centimeters), shown in red in the highlighted track, as well as a look at the shape and direction of travel of the leading edge of the tsunami. The SWOT data, shown in the highlighted swath running from the southwest to the northeast in the visual, is plotted against a forecast model of the tsunami produced by the U.S. National Oceanic and Atmospheric Administration (NOAA) Center for Tsunami Research. Comparing the observations from SWOT to the model helps forecasters validate their model, ensuring its accuracy.
“A 1.5-foot-tall wave might not seem like much, but tsunamis are waves that extend from the seafloor to the ocean’s surface,” said Ben Hamlington, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California. “What might only be a foot or two in the open ocean can become a 30-foot wave in shallower water at the coast.”
The tsunami measurements SWOT collected are helping scientists at NOAA’s Center for Tsunami Research improve their tsunami forecast model. Based on outputs from that model, NOAA sends out alerts to coastal communities potentially in the path of a tsunami. The model uses a set of earthquake-tsunami scenarios based on past observations as well as real-time observations from sensors in the ocean.
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The SWOT data on the height, shape, and direction of the tsunami wave is key to improving these types of forecast models. “The satellite observations help researchers to better reverse engineer the cause of a tsunami, and in this case, they also showed us that NOAA’s tsunami forecast was right on the money,” said Josh Willis, a JPL oceanographer.
The NOAA Center for Tsunami Research tested their model with SWOT’s tsunami data, and the results were exciting, said Vasily Titov, the center’s chief scientist in Seattle. “It suggests SWOT data could significantly enhance operational tsunami forecasts — a capability sought since the 2004 Sumatra event.” The tsunami generated by that devastating quake killed thousands of people and caused widespread damage in Indonesia.
More About SWOT
The SWOT satellite was jointly developed by NASA and CNES, 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: