Greenland's 650-Foot Mega-Tsunami Shook Earth For 9 Days, Satellite Data Confirms

In September 2023, a colossal landslide in Greenland's Dickson Fjord unleashed a 650-foot (200-metre) high mega-tsunami, causing the Earth to vibrate every 90 seconds for nine consecutive days. This unprecedented seismic event puzzled scientists until recent satellite data provided clarity. 

The Surface Water and Ocean Topography (SWOT) satellite, equipped with advanced radar technology, detected the persistent oscillations-known as seiches-within the fjord. These seiches resulted from approximately 25 million cubic meters of rock and ice crashing into the fjord, a consequence of glacier melting due to climate change.

The findings were published Tuesday (June 3) in the journal Nature Communications. The fjord's unique geography trapped the tsunami's energy, preventing it from dissipating quickly. This event has highlighted the profound and far-reaching impacts of global warming, triggering the need for vigilant monitoring of vulnerable regions.

Also Read | When Earth Shook For 9 Days After Rockslide Triggered 650-Foot Tsunami

To prove their theory, the researchers linked these observations to small movements of the Earth's crust measured thousands of kilometres away. This connection enabled them to reconstruct the characteristics of the wave, even for periods that the satellite did not observe. The researchers also reconstructed weather and tidal conditions to confirm that the observations could not have been caused by winds or tides.

Lead author Thomas Monahan (DPhil student, Department of Engineering Science, University of Oxford) said in a statement, "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. This study shows how we can leverage the next generation of satellite earth observation technologies to study these processes."

"SWOT is a game changer for studying oceanic processes in regions such as fjords, which previous satellites struggled to see into."

Co-author Professor Thomas Adcock (Department of Engineering Science, University of Oxford) said, "This study is an example of how the next generation of satellite data can resolve phenomena that have 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. 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."