7 days ago
‘Mega-tsunami' mystery solved — source of seismic activity that shook the world for 9 days revealed
This ought to cause a wave of panic.
Back in 2023, scientists were perplexed by a mysterious seismic signal that shook the world every 90 seconds for nine days.
Now, two years later, satellite footage has revealed the frightening source of these vibrations — giant mega-tsunamis sloshing around a Greenland fjord, per a 'Nature Communications' study.
The massive walls of water — one of which measured 650 feet tall, or about half the height of the Empire State Building — were reportedly caused by the collapse of a massive mountainside that was triggered by a warming glacier, per the report.
A total of 25 million cubic meters of rock and ice crashed into remote Dickson Fjord in East Greenland, the Daily Mail reported.
This spawned colossal waves known as seiches that undulated back and forth in the water body for nine days like a giant bathtub or wave pool — hence the mysterious reverberations, Live Science reported.
Study co-author Professor Thomas Adcock, who teaches engineering science at the University of Oxford, dubbed the findings 'an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past.'
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'That is an enormous wall of water bouncing back and forth,' study lead author Thomas Monahan, a graduate student in engineering science at the University of Oxford, told the Daily Mail.
He estimated that the force exerted over the length of the fjord was 500 Giga Newtons, the 'equivalent to the amount of force produced by 14 Saturn V rocket ships launching at once.'
While this seismic phenomenon was felt around the world, there were no observations of these tsunamis or landslides to confirm the theory. Even a Danish military vessel that entered the fjord three days into the first seismic event didn't observe the seiche rocking the planet.
Thankfully, the Oxford researchers were able to fill in the blanks by analyzing data captured by the new Surface Water and Ocean Topography (SWOT) satellite, which, as the name suggests, tracks water on the surface of the ocean.
Using a tool called Ka-band Radar Interferometer (KaRIn), the tech can map 90% of all water on the ocean's surface.
Copernicus Sentinel-2 satellite image of the Dickson Fjord overlaid with sea-surface height measurements from the SWOT satellite.
Thomas Monahan
The traditional tsunami-measuring method, satellite altimetry, involves transmitting radar pulses onto the ocean's surface from orbit and then measuring the wave's height based on the time it takes for the pulse to return.
Unfortunately, this technique is somewhat limited as it can't conduct accurate measurements in a confined space such as the fjord.
By contrast, KaRin can pinpoint radar signals' returns with shocking precision using two massive antennae.
Armed with this tech, Fjord forensics experts were able to observe cross-channel slopes moving in opposite directions between the fjord, confirming their presence. They then cross-referenced this with seismic observations, as well as weather and tidal readings, to recreate the waves and connect them to the reverberations.
Study co-author Professor Thomas Adcock, who teaches engineering science at the University of Oxford, dubbed the findings '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,' he said. 'However, to get the most out of these data, we will need to innovate and use both machine learning and our knowledge of ocean physics to interpret our new results.'
Monahan deemed the cutting-edge tech particularly crucial.
'This study shows how we can leverage the next generation of satellite Earth observation technologies to study these processes,' he said.
