Earth's 9-Day Mystery Tremors Finally Solved!

Mega-Tsunamis That Shook the World for 9 Days: Satellite Images Reveal the Source

In a fascinating display of scientific detective work, researchers have finally pinpointed the cause of mysterious seismic events that reverberated across the globe for nine days in September and October 2023. The answer, revealed through groundbreaking satellite imagery, points to colossal landslides in East Greenland's Dickson Fjord, triggering a series of mega-tsunamis.

The Mystery Unfolds:

The initial detection of these unusual Earth tremors baffled scientists. Global seismometers picked up minor tremors occurring every 90 seconds, a phenomenon that persisted for over a week. Natural tectonic activity couldn't account for the sustained shaking, leaving researchers searching for an alternative explanation.

The Landslide Hypothesis:

After months of investigation, two independent studies in 2024 proposed a compelling hypothesis: massive landslides plunging into Dickson Fjord had generated "mega-tsunamis." These weren't your typical tsunamis; they were seiches – enormous standing waves sloshing back and forth within the fjord. The theory suggested that this sloshing action was subtly influencing Earth's crust, creating the detected seismic signals.

However, as Thomas Monahan, a Schmidt AI in Science fellow at the University of Oxford, noted, "there were some big uncertainties that made it difficult to fully corroborate that this was actually the root cause."

Satellite Sleuthing: The Missing Piece

Monahan and his team embarked on a mission to validate the landslide-tsunami hypothesis. Their research, published in Nature Communications, presents the first direct satellite observations of these seiches, definitively linking them to the seismic anomalies.

NASA's SWOT Satellite: A Game-Changer

The key to this breakthrough lies in data from NASA’s Surface Water Ocean Topography (SWOT) satellite. Launched in December 2022, SWOT is designed to map water height across 90% of the Earth's surface using a technique called satellite altimetry. Here's how it works:

• The satellite emits radar pulses towards Earth.
• It measures the time it takes for the signals to bounce back.
• This data allows for precise calculations of surface water levels.

Unlike conventional altimeters, which struggled to capture data in complex fjord regions due to terrain and observation gaps, SWOT boasts a cutting-edge instrument. Its twin antennas triangulate return signals, providing incredibly high-resolution snapshots of surface water elevation.

Unearthing the Anomaly:

"We were able to essentially unearth the fact that there was a significant anomaly in the fjord exactly when we would expect this wave to occur," Monahan explained.

But the team needed more than just a correlation between the seiches and seismic signals. They needed proof that the waves could actually generate the tremors.

Connecting the Dots:

The researchers achieved this by linking the SWOT snapshots to subtle movements in Earth's crust, detected by seismic stations thousands of miles away. By combining continuous seismic data with intermittent satellite observations, they reconstructed the wave's characteristics, even when SWOT wasn't actively observing.

Furthermore, they ruled out alternative explanations, such as weather or tidal conditions, solidifying the seiches as the source of the tremors.

The Culprit: A Warming Glacier

The triggering event? A warming glacier collapsing in on itself. This triggered massive landslides, which, upon impact with the fjord, generated mega-tsunamis reaching heights of **200 meters (600 feet)**!

A Concerning Trend:

While mega-tsunamis have been documented on Greenland's west coast, this was the first instance in the east. "To see this phenomenon spreading to other parts of the ice sheet 'is concerning'," Monahan stated, highlighting the accelerating impact of climate change in the region.

A Global Wake-Up Call:

"I think what this study really emphasizes is that—well, it sounds silly to say—but climate change is a global phenomenon," Monahan concluded.

The waves that shook the world serve as a stark reminder that changes in remote regions like the Arctic can have far-reaching consequences, underscoring the urgency of addressing rising global temperatures.

Tags: Earth tremors, seismic events, Greenland, mega-tsunamis, Dickson Fjord, landslides, seismic signals, seiches, scientific studies, Earthquakes, climate change, SWOT satellite, NASA, Arctic.

Source: https://gizmodo.com/mega-tsunamis-that-shook-the-world-for-9-days-revealed-in-new-satellite-images-2000610544