A massive landslide in Greenland caused a mega-tsunami that lasted nine days and sent seismic vibrations globally. Recorded in September 2023, researchers found the prolonged seismic signals puzzling. After months of investigation, 68 scientists from 40 institutions revealed that climate change was a key factor in this disaster.
A MYSTERIOUS SEISMIC SIGNAL ACROSS THE GLOBE
In September 2023, seismometers around the world detected a strange global seismic signal that baffled experts. Unlike typical earthquake vibrations, these signals displayed only a single, monotonous frequency and lasted nine days. Seismologists initially classified the event as an unidentified seismic object (USO), with no clear explanation. The vibrations reached from the Arctic to Antarctica, sparking curiosity among scientists.
THE GREENLAND LANDSLIDE AND MEGA-TSUNAMI
The seismic signals were eventually linked to a landslide in eastern Greenland, where a 1.2-kilometer-high mountain collapsed into the Dickson Fjord. The landslide triggered a mega-tsunami, with water splashing 200 meters into the air and generating a wave up to 110 meters high. The fjord, stretching 10 kilometres, became a watery playground for the tsunami as it moved back and forth, with little energy escaping.
Using a mathematical model, scientists recreated the angle and speed of the landslide, showing how the water’s movement would continue for nine days, creating seismic vibrations that traveled through Earth’s crust. The back-and-forth motion occurred every 90 seconds, perfectly matching the recorded global seismic signals.
HOW CLIMATE CHANGE TRIGGERED THE LANDSLIDE
The study identified climate change as the key factor behind the landslide. The glacier at the mountain’s base had thinned due to warming temperatures, destabilizing the rock face above. When the glacier could no longer hold up the massive rock mass, it collapsed into the fjord, creating the massive wave.
Dr. Stephen Hicks, co-author of the study from University College London, emphasized the interconnectedness of Earth’s systems:
“This event highlights how climate change in the atmosphere can destabilize glacier ice, leading to landslides that affect the hydrosphere and even send vibrations through Earth’s crust.”
IMPACT OF THE MEGA-TSUNAMI ON GREENLAND’S FJORDS
The mega-tsunami didn’t stop at Dickson Fjord. Seventy kilometers away, the tsunami’s waves, still four meters high, damaged a research base on the island of Ella Ø and destroyed archaeological sites. The fjord, a popular route for tourist cruise ships, was fortunately devoid of vessels at the time. Had a ship been present, the consequences could have been catastrophic, with 110-meter waves likely causing immense destruction.
SEISMIC RECORDINGS FROM AROUND THE WORLD
The global reach of the seismic signals sparked intrigue among scientists. Unlike the rumblings of an earthquake, the tsunami vibrations contained only a single frequency. This unique signal was detected by seismometers worldwide, offering an opportunity for researchers to track and study the event in real-time.
Dr. Hicks, who first noticed the anomaly, remarked on the unprecedented nature of the event:
“We’ve never before recorded a seismic wave that lasted for several days and traveled globally with such a distinct, single frequency. It was a seismic signal unlike anything we’d seen.”
UNITING SCIENCE FOR ANSWERS: AN INTERDISCIPLINARY INVESTIGATION
The study required a multidisciplinary effort, involving 68 scientists from 15 countries. Combining seismic data, satellite imagery, field measurements, and numerical simulations, the team meticulously reconstructed the landslide and tsunami. They worked closely with the Danish military, who sailed into the fjord days after the event to inspect the collapsed mountain faceand collect vital data.
Dr. Kristian Svennevig, lead author from the Geological Survey of Denmark and Greenland, described the collaboration as essential:
“No one had the faintest idea what caused the signal initially. Through an immense international effort, we managed to piece together this extraordinary event.”
A GLIMPSE INTO THE FUTURE OF CLIMATE CHANGE DISASTERS
The landslide in Greenland is a stark reminder of the escalating risks posed by climate change. As the planet warms, glaciers are retreating, leaving landscapes unstable. This event is the first-ever recorded landslide and tsunami in eastern Greenland, but it may not be the last. The study’s authors warn that such occurrences will likely become more common as glaciers continue to thin.
Co-author Thomas Forbriger, from the Karlsruhe Institute of Technology, highlighted the importance of global seismic networks:
“Without the worldwide network of high-fidelity seismometers, we wouldn’t have detected or analyzed this unique event.”
ADVANCING TSUNAMI MODELING
The duration and magnitude of this event challenged traditional tsunami models, which are typically designed to simulate only a few hours of wave activity. To capture the nine-day durationof this mega-tsunami, the team had to develop new numerical methods with unprecedented resolution.
Dr. Anne Mangeney, a co-author from Université Paris Cité, emphasized the significance of this development:
“This event opens new doors for improving tsunami models, especially in regions affected by glacial retreat. Our understanding of long-lasting events like this has advanced significantly.”
FUTURE OF LANDSLIDE AND TSUNAMI MONITORING
As climate change accelerates, the need for better monitoring and early warning systems is becoming increasingly urgent. Regions that were once considered geologically stable may no longer be safe from landslides and tsunamis. The study concludes that governments and scientists must focus on characterizing and monitoring these vulnerable areas to provide early warnings for future disasters.
The Greenland event demonstrates the cascading effects of climate change on Earth’s systems. From the thinning glacier to the landslide, to the global seismic vibrations, the event represents a complex interplay of environmental forces.
