In 2023, scientists successfully observed a peculiar earthquake event that persisted for nine consecutive days, confirming its origin.
A massive wave, measuring 650 feet (200 meters) tall—approximately half the height of the Empire State Building—swept into the Dixon Fjord in East Greenland, producing seismic waves that shook the Earth’s crust throughout September.
The initial signal puzzled researchers, but ground and satellite imagery tracked the sources leading to landslides in the fjord. These landslides generated waves called Seichi, resulting from the climate-induced melting of the glaciers that feed the fjord. Nevertheless, direct evidence of these Seichi waves was not detected.
New satellite observations that monitor sea level have validated this theory. These findings were published in a journal on June 3, available at Natural Communication.
“Climate change is generating new, unseen extremes,” stated lead author Thomas Monaghan, a graduate student in Engineering Science at Oxford University; mentioned in a statement. “These extremes are changing most rapidly in remote regions like the Arctic, where physical sensors are less effective. This study demonstrates how advanced satellite-earth observation technologies can aid in understanding these phenomena.”
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Normally, scientists employ satellite altimeter measurements to analyze tsunami wave movements. This technique involves sending radar pulses from space to measure wave heights based on the time it takes for the signals to return.
However, due to extended gaps in satellite coverage and their instruments measuring only what is directly below them, they are unable to detect variations in water height over small areas, like those found in a fjord.
To validate the presence of Seichi waves, scientists utilized data from the new Surface Water and Ocean Topography (SWOT) Satellite, a collaborative project between NASA and the French space agency CNES. Launched in December 2022, the satellite employs a KA-band radar interferometer (Karin) to map the water surface in 90% of the ocean.
Karin utilizes two antennas situated on either side of the satellite to accurately triangulate the radar pulse return signals.
Data collected from SWOT on top of the fjord between the two massive tsunamis revealed two cross-channel slopes moving in opposite directions, confirming their existence. Earthquake readings from thousands of miles away, coupled with weather and tide measurements, allowed scientists to reconstruct the waves, ultimately linking them to the mysterious seismic signals.
“This research exemplifies how next-generation satellite data can resolve phenomena that have previously perplexed scientists,” stated co-author Thomas Adcock, an engineering science professor at Oxford University.
“We are uncovering new insights into extreme ocean phenomena such as tsunamis, storm surges, and rogue waves,” he continued. “However, to maximize the utility of this data, we need to innovate and apply both machine learning and ocean physics to interpret the findings.”
Source: www.livescience.com