In September 2023, a strange global earthquake signal was seen every 90 seconds in nine days – and was repeated a month later. About a year later, two scientific studies suggested that the cause of the earthquake was two mega tsunami, which was mobilized by two major land sliding in remote East Greenland Fijord, which was caused by an unknown glacier heat. It was believed that the waves were trapped in the Fijord system, creating standing waves (or sichches) that did not go back and forth, causing mysterious gestures.
However, there were no observations of these seches to confirm this theory. Even a Danish military vessel that visited Fijord in a three -day earthquake, did not observe the wave that is shaking the earth.
In new research, Oxford researchers used a novel analysis technique to translate satellite ultraviolet data. This records how much time it takes the pulse of a radar from the satellite to the surface and back to the surface. Until now, traditional satellite ultimators were unable to get the wave evidence due to the long difference between observations, and the fact that they sample direct data under the spacecraft, producing 1D profiles with sea level. This makes them unable to disclose the differences in the height of the water needed to find the waves.
The study used data obtained by the new level of water ocean Tapgraphy (SWOT) satellite, which was launched in December 2022 to map the height of water at 90 % of the ground level. The cutting edge band at the center of the SWOT is the radar interface (carin) device, which uses two antenna riding a 10 meter faster on both sides of the satellite. Both of these antenna work together to make a triangle of return signs that leap from the radar pulse.
Using crane data, researchers made maps of Greenland Fijord high at various time points after both tsunamis. They showed clear, cross -channel slopes with differences of height up to two meters. Significantly, the slopes in these maps have occurred in the opposite direction, which shows that the water moves backwards and across the channel.
To prove their theory, the researchers linked these observations to the small movements of the earth layer, which is measuring thousands of kilometers away. This series enabled them to rebuild the properties of the wave, even for periods that the satellite did not observe. Researchers also formed the weather and maritime conditions to confirm that observations may not be due to winds or maize.
The leading author Thomas Monhan (Defal Student, Department of Engineering Science, Oxford University) said: “Climate change is giving rise to new, unseen extremes. It is changing rapidly in remote areas, such as Arctic, where we have a limited use of physical senses.
“SWOT is a game changer to study maritime operations in regions like SWOT Fijords, which struggled to see the previous satellite.”
Co -author Professor Thomas Adekak (Department of Engineering Science, University of Oxford) said: “This study is an example of how the next generation of satellite data remains a matter of time. Oceanic physics to translate our new results.”
