A colossal landslide in a Greenland fjord last September triggered an extraordinary event: a wave that caused seismic vibrations for nine days, which were detected by sensors around the world. Scientists were initially baffled by the mysterious tremors, but after months of investigation, they discovered that the source was a 200-meter-high mega-tsunami caused by a massive landslide in Dickson Fjord, located in East Greenland.

The Unfolding of the Event

The unusual seismic activity was first detected in September 2022, with sensors picking up a recurring signal every 90 seconds over the course of nine days. This signal, which did not resemble any typical earthquake pattern, puzzled scientists across the globe. Dr. Stephen Hicks, from University College London (UCL), referred to the phenomenon as an “unidentified seismic object.”

The signal led to an international scientific collaboration. At the same time that the seismic anomaly was being debated online, researchers in Denmark received reports of a tsunami in a remote fjord in East Greenland. By combining seismic data, satellite imagery, and photographic evidence provided by the Danish Navy, scientists were able to pinpoint the source of the tremors to Dickson Fjord.

Satellite images revealed a massive cloud of dust and drastic changes to the landscape before and after the event. The researchers determined that a mountainside had collapsed, sending 25 million cubic meters of rock—equivalent to the volume of 25 Empire State Buildings—plunging into the fjord, along with part of a glacier. This caused the mega-tsunami, with a wave that reached 200 meters in height, leaving visible sediment marks on the glacier’s surface.

A Wave Trapped for Nine Days

Unlike typical tsunamis, which dissipate as they spread through the open ocean, the wave in Dickson Fjord was trapped in the narrow fjord, its energy unable to escape. As a result, the wave oscillated back and forth within the fjord for an unprecedented nine days, continuously generating seismic vibrations that were picked up by global sensors.

“We’ve never seen such a large-scale movement of water over such a long period,” said Dr. Hicks. He explained that this was possible because the fjord, located about 200 kilometers inland, prevented the wave from losing its energy quickly.

Climate Change: A Critical Factor

The research team concluded that the landslide, and the resulting tsunami, was triggered by the ongoing effects of climate change. Greenland’s glaciers have been melting at an accelerated pace due to rising temperatures, weakening the structures that support its mountainous terrain. In this case, the glacier that had once supported the mountainside had thinned to the point where it could no longer hold the mass in place, leading to the catastrophic collapse.

“This glacier was supporting the mountain, and it got so thin that it just stopped holding it up,” Dr. Hicks explained. “It shows how climate change is now impacting these areas in ways we haven’t seen before.”

Increasing Landslide-Triggered Tsunamis

While the Dickson Fjord event occurred in a remote area, scientists have raised concerns about similar events becoming more frequent, especially in the Arctic region, where glaciers are rapidly retreating. According to Dr. Kristian Svennevig from the National Geological Surveys for Denmark and Greenland (GEUS), the event highlights the increasing frequency of giant, tsunami-causing landslides in Greenland.

Though no ships were in the area at the time of the Dickson Fjord landslide, many fjords in Greenland are popular destinations for Arctic cruise ships, increasing the potential risks for future events. Dr. Svennevig emphasized the need for more research into these phenomena to better understand and predict such occurrences.

A Global Impact

One of the most striking aspects of the Dickson Fjord event is its far-reaching impact. The seismic vibrations generated by the trapped wave were detected by sensors all over the world, marking what Dr. Hicks described as possibly the first climate change-related event to affect the Earth’s crust globally. The sheer scale of the event and its connection to climate change underscore the urgent need to address the environmental shifts that are reshaping landscapes, not only in the Arctic but around the globe.

Conclusion

The Dickson Fjord tsunami is a stark reminder of how climate change is contributing to increasingly dramatic geological and environmental events. As Greenland’s glaciers continue to melt, the likelihood of similar, potentially devastating landslides and tsunamis grows. This event, with its unprecedented duration and scale, highlights the importance of ongoing research into the effects of climate change on the planet’s most vulnerable regions.