A satellite flying over Greenland last year captured an aerial view of the tsunami that rocked the country’s fjord, and now researchers have published their analysis of the stunning visuals.
Satellite images can reveal what was previously invisible and provide new perspectives on ancient objects. From atmospheric conditions to the slow death of forests and garbage piles, images from the air and near-Earth orbit can help scientists better understand the planet.
The tsunami occurred in Dickson Fjord in September 2023, and was caused by a rockslide that caused the Earth to shake inexplicably for nine days. Every 90 seconds that week-and-change, the waters of the fjord moved back and forth, bounded by the 6,000-foot (1,830-meter) walls of the channel. The researchers published an analysis of the earthquake event e Science in September, recounting how that 880 million cubic meters (25 million cubic meters) of ice, rock and mud caused a tsunami. As the power could not dissipate, the fjord tsunami shook the Earth for more than a week.
As the tsunami churned the fjord, the Surface Water and Ocean Topography, or SWOT, satellite was passing overhead. Operated by NASA and France’s Center National d’Études Spatiales (CNES), SWOT was able to study how the tsunami changed water levels in the 1,772-foot-deep (540-meters-deep) fjord.
“The SWOT occurred at a time when the water accumulated very high on the north wall of the fjord,” said Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory, in a laboratory release. “Seeing the shape of the tide – that’s something we wouldn’t have done before SWOT.”
The fjord is 1.7 miles (2.7 km) wide. Based on the SWOT data, the team found that the tsunami caused the water levels on one side of the fjord (its north side) to be 1.2 feet higher than the water levels on its south side.
SWOT collected this data using its interferometer, a device that uses interference patterns to measure the distance between objects. Interferometry can be done with extreme precision, making it the go-to tool for scientists who take very precise measurements to measure things like the warping of the fabric of space-time.
“The resolution of the KaRIn radar was good enough to look between the narrow walls of the fjord,” said Lee-Lueng Fu, SWOT project scientist, in the same release. “The standard altimeters used to measure sea level are too large to resolve small bodies of water.”
The tsunami caused about $200,000 worth of damage, as reported in our original coverage of the survey. But the SWOT picture adds a compelling new dimension to the chaotic tsunami—it shows the chaos from above.
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