Earth vibrated for 9 DAYS following a 650ft mega-tsunami, scientists confirm

Daily Mail​

03-06-2025

Back in September 2023, scientists around the world were baffled by a bizarre seismic signal that repeated every 90 seconds for nine days.
Now, almost two years later, scientists have confirmed the root cause of this bizarre phenomenon.
Using novel satellite technology, experts from the University of Oxford have shown that the strange signal was caused by a 650ft (200 metre) mega-tsunami.
This colossal wave was triggered by the collapse of a 3,937ft (1,200 metre) mountain into the remote Dickson Fjord in Greenland, unleashing 25 million cubic metres of rock and ice.
The huge wave became trapped in the Fjord, bouncing back and forth in the form of a standing wave or 'seiche'.
Lead author Thomas Monahan, Schmidt AI in Science Fellow at Oxford University, told MailOnline: 'The standing wave itself was massive.
'We estimate it to initially be 7.9 metres in height - that is an enormous wall of water bouncing back and forth.
'An estimate of the force that exerts over the length of the fjord is 500 Giga Newtons, which is equivalent to the amount of force produced by 14 Saturn V rocket ships launching at once, and was enough to shake the earth for days.'
Part of what made the 2023 seismic event so mysterious was that no one directly observed the tsunami in order to prove it was the source of the vibrations.
Even a Danish military vessel visiting the fjord in the days after the tsunami was unable to see any evidence of a standing wave.
This was because the wave rapidly reduced in height even as it continued to produce seismic signals.
Starting at around 23ft (seven metres) in height by the time it had crossed the 6.2-mile (10km) extent of the Dickson Fjord, the standing wave had become just centimetres tall after a few days.
Combined with the fact that the military didn't know what they were looking for, this meant the wave went completely unobserved.
Now, in a new paper published in Nature Communications, Mr Monahan and his colleagues have used novel satellite technology to make the first observations of the mega-tsunami.
The scientists used 'satellite altimetry data', which works out the height of the Earth's surface by measuring how long it takes for radar signals to bounce off the surface.
Due to the long gaps between observations, normal satellite altimetry isn't able to measure precisely enough to capture something like a wave.
However, the researchers used data captured by the new Surface Water Ocean Topography (SWOT) satellite launched in 2022.
SWOT uses two antennae held on either side of a 33ft (10 metre) arm which work together to make extremely accurate measurements.
This dataset covers over 90 per cent of the Earth's surface, allowing scientists unprecedented views of the world's waterways.
Mr Monahan says: 'Unlike previous satellites, SWOT provides detailed two-dimensional measurements of sea surface height, down to the centimetre, across the entire globe, including in hard-to-reach areas like fjords, rivers, and estuaries.
'Because SWOT can "see" into remote regions from space, it gave us an unprecedented view into Dickson Fjord during the seiche events in September and October.
'By capturing high-resolution images of sea-surface height at different times, we could estimate how the water surface tilted during the wave — in other words, the slope of the seiche.'
The researchers then combined these observations with seismic data taken from thousands of miles away to reconstruct the size and characteristics of the waves.
Additionally, the researchers reconstructed the local weather and tide conditions to confirm that the wave could not have been caused by anything other than a massive landslide.
Co-author Professor Thomas Adcock, of the University of Oxford, says: 'This study is an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past.
'We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves.'
These abilities will become even more valuable in the future as climate change creates more freak disasters like the 2023 tsunami.
As the climate gets hotter, glacial collapses will become more common and put more lives at risk.
Research conducted by University College London in 2024 found that the collapse occurred because a warming climate had weakened the surrounding glacier.
Dickson Fjord is a popular route for tourist cruise ships and, had a ship been in the fjord at the time, the impact could have been devastating.
Last week flood waters created by the partial collapse of the Birch glacier in Switzerland destroyed 90 per cent of the nearby village of Blatten amidst fears that more villages could still be at risk.
Mr Monahan says: 'Climate change is giving rise to new, unseen extremes. These extremes are changing the fastest in remote areas, such as the Arctic, where our ability to measure them using physical sensors is limited.'
WHAT CAUSES TSUNAMIS?
A tsunami, sometimes called a tidal wave or a seismic sea wave, is a series of giant waves that are created by a disturbance in the ocean.
The disturbance could be a landslide, a volcanic eruption, an earthquake or a meteorite; the culprit is most often an earthquake.
If the landslide or earthquake triggering the tsunami occurs nearby the shore, inhabitants could see its effects almost immediately.
The first wave of the tsunami can arrive within minutes, before a government or other institution has time to issue a warning.
Areas that are closer to sea level have a higher risk of being affected by the waves.
Those less than 25 feet from sea level are the most dangerous.
The cause of death most frequently associated with tsunamis is drowning. Additional hazards include drinking water contamination, fires and flooding.
Initial tsunami warnings are usually based on seismic information only.
Inhabitants of coastal areas that might be exposed to a tsunami are encouraged to follow evacuation routes in the event that they receive a tsunami warning.
They should seek higher ground or move inland immediately to get away from the ocean.