The Tsunami That Rocked Greenland: A Nine-Day Oceanic Mystery!

In a shocking incident in September 2023, East Greenland experienced a colossal landslide that triggered a mega-tsunami in the isolated Dickson Fiord. The seismic activity from this event resonated around the globe for an unprecedented nine days, leaving scientists puzzled about its origins and mechanics.

The landslide occurred in an uninhabited area; however, monitoring stations worldwide picked up an immense seismic signal. These readings revealed waves crashing back and forth through the fiord roughly every 90 seconds, raising alarm for experts far beyond Greenland's shores.

Fortunately, no cruise ships were present in the fiord at the time; however, a vessel did enter the fiord the following day. Crew members discovered that a research station’s boat and a shipping container, which are typically secure on land, had been swept into the sea. Additionally, the research station itself sustained significant damage.

Unidentified Seismic Object: Mystery Unraveled

Kristian Svennevig from the Geological Survey of Denmark and Greenland (GEUS) initially suspected either an earthquake or a tsunami. Yet, the nine days of seismic reverberations defied standard earthquake or tsunami patterns, prompting scientists to label the phenomenon as a USO — an Unidentified Seismic Object.

For an entire year, Svennevig and a team of 68 scientists from 15 countries employed an arsenal of methods, including seismometer data, satellite imagery, field measurements, and tsunami simulations, to decipher the shocking event.

The investigation began with satellite imagery and aerial photography, revealing the catastrophic impact on vegetation along the fiord's shore, where plant life had been completely annihilated. On nearby Ella Island, plants were missing up to four meters above the water line, with the impact zone extending as researchers moved westward. This evidence suggested that waves originated from the west and traveled eastward through the fiord.

The Wave Phenomenon: Unprecedented Duration of Movement

Additional satellite images captured on September 15 and 17, just before and after the tsunami struck, disclosed the disappearance of a mountain ridge west of the fiord. Approximately 25 million cubic meters of rock and ice plunged into the sea, generating a tremendous 200-meter-high tsunami that raced across the fiord at speeds of 160 km/h. Though the height of the waves diminished to around seven meters within minutes, they continued to bounce back and forth against the cliffs for an astonishing nine days.

Typically, tsunamis dissipate within hours, but due to the narrow geometry of the fiord, this tsunami retained its energy much longer than usual. As Stephen Hicks, co-author of a study on the event, explained, "This landslide occurred about 200 km inland from the open ocean, and these fiord systems are incredibly complex, preventing the wave from losing its energy."

Climate Change: The Root Cause?

Investigations concluded that climate change was the catalyst for this calamitous landslide. The glacier, which supports the mountain adjacent to the fiord, thinned due to rising temperatures and could no longer bear the weight of the rock above it. This ultimately led to the catastrophic collapse.

This incident isn’t an isolated case. In 2017, a similar landslide in Greenland's Karrat Fjord triggered a 100-meter-high tsunami that devastated the remote community of Nuggaatsiaq, killing four and injuring nine. Buildings were swept away, and entire boats were found 50 meters up the hillside. As a result, the community was evacuated and remains abandoned today, highlighting the pressing threat of such natural disasters as our climate continues to warm.

Researchers are now calling for enhanced monitoring systems in mountainous regions to safeguard against future events, which are expected to become increasingly frequent as rising temperatures destabilize frozen landscapes. The world watches closely as scientists continue to unravel the implications of climate change on disasters like this and the broader global environment.