A puzzling seismic phenomenon that affected the globe for over a week has finally found an explanation through extensive scientific research.
In September 2023, global seismometers detected unusual tremors occurring every 90 seconds for nine consecutive days.
This peculiar activity was followed by similar occurrences a month later, leaving scientists struggling to identify its source, as conventional tectonic processes could not account for the anomalies.
After a year of investigation, two independent studies in 2024 proposed a theory: the seismic signals originated from two massive landslides that triggered mega-tsunamis within the Dickson Fjord in East Greenland.
These gigantic standing waves, known as seiches, were believed to have caused minor movements within the Earth’s crust, but the studies faced significant uncertainties regarding the accuracy of their hypotheses.
Thomas Monahan, a Schmidt AI in Science fellow at the University of Oxford, led a research team to verify these claims.
In a recent study published in the journal Nature Communications, Monahan and his colleagues revealed direct satellite observations of the seiches, establishing a definitive link to the seismic anomalies detected globally.
The research utilized data from NASA’s Surface Water Ocean Topography (SWOT) satellite, which launched in December 2022.
Unlike conventional altimeters that often miss critical data due to gaps between observations, SWOT uses advanced altimetry techniques with dual antennas to capture high-resolution measurements of surface water levels across complex terrain, such as fjords.
This technological advancement allowed researchers to acquire detailed snapshots of changes in sea surface height during the 2023 seismic events, leading them to calculate the slopes of massive waves that had formed in the fjord.
Monahan stated, “We were able to unearth the fact that there was a significant anomaly in the fjord exactly when we would expect this wave to occur.”
However, it was essential to establish a solid causal relationship between the seiches and the seismic signals, as the researchers initially only demonstrated temporal correlation.
To strengthen their findings, they correlated the SWOT data with seismic movements detected at monitoring stations located thousands of miles away from the fjord.
This integration of continuous seismic information and intermittent satellite observations allowed the team to reconstruct the wave characteristics, even during periods not directly observed by SWOT.
Additionally, the study ruled out the possibility that the seismic activity was related to weather or tidal influences, conclusively attributing the tremors to the seiches.
According to Monahan, the waves were caused by the collapse of a warming glacier.
“When it struck the fjord, this generated massive mega-tsunamis approximately 200 meters or 600 feet tall,” he explained.
Significantly, Monahan noted that this was the first occurrence of a mega-tsunami of this magnitude in Eastern Greenland, even though similar events had been documented on the territory’s west coast.
The spread of such phenomena across different areas of the ice sheet raises alarm bells regarding the accelerating impact of climate change in the region.
Monahan emphasized, “This study really underscores that climate change is a global phenomenon.”
He further elaborated that some of the most rapid transformations are occurring in Arctic and remote regions, with effects that may not be immediately visible.
Understanding and quantifying these changes is crucial, as they will inevitably affect populations in other parts of the world.
The seismic waves that reverberated globally serve as a stark reminder of the broader implications of rising global temperatures.
The implications of this research extend beyond the scientific community, highlighting the necessity for urgent action against climate change in light of the alarming events linked to Greenland’s glacial dynamics.
This revelation not only aids in understanding past seismic events but also warns of potential future occurrences influenced by the ongoing climate crisis.
image source from：https://gizmodo.com/mega-tsunamis-that-shook-the-world-for-9-days-revealed-in-new-satellite-images-2000610544
