A massive mega tsunami triggered by a collapsing mountainside in eastern Greenland sent seismic waves around the world for nine continuous days, according to scientists studying one of the strangest geological events ever recorded.
The extraordinary phenomenon began on September 16, 2023, when more than 25 million cubic yards of rock and ice crashed into the narrow Dickson Fjord in Greenland. The impact generated a towering 650-foot wave that surged through the fjord and created a long lasting oscillation in the water, producing rhythmic seismic pulses felt across the planet.
Researchers said the mysterious signal initially puzzled scientists worldwide because it did not resemble a normal earthquake. Seismic stations repeatedly detected smooth vibrations every 92 seconds, continuing for more than a week.
The event was eventually traced to the remote fjord after satellite images revealed a fresh scar on a mountainside where a huge section had collapsed into the water. Scientists found that the giant wave repeatedly bounced back and forth within the confined fjord, creating a “seiche” a standing wave motion that continuously pressed against the seafloor and generated the unusual seismic activity.
According to researchers, the mega-tsunami reached nearly 650 feet in height immediately after impact, making it one of the largest waves observed in modern history. The surge damaged equipment at a research station on Ella Island, though fortunately no people were present in the area at the time.
The discovery brought together more than 70 researchers from 41 institutions around the world. Using advanced computer models, satellite observations and seismic data, scientists reconstructed how the landslide and resulting wave created the prolonged vibrations.
Researchers linked the disaster to climate change, noting that melting glaciers had weakened the mountainside over time. Glacier ice previously acted as a natural support structure for the slope, but warming temperatures and retreating ice likely contributed to the collapse.
Scientists warned that such events could become more common in the Arctic as climate change accelerates glacier melt and destabilises mountain slopes. The incident has also raised concerns for increasing cruise tourism and shipping activity in Arctic waters.
The study additionally highlighted the growing role of next-generation satellite technology in monitoring remote environmental disasters. Data from the Surface Water and Ocean Topography (SWOT) satellite mission helped researchers measure changes in sea surface height within the fjord, providing new insight into extreme ocean events.
Experts now hope the findings will improve future disaster forecasting systems by combining satellite imagery with real-time seismic monitoring. Researchers are also examining historical seismic records to identify whether similar hidden mega tsunami events may have occurred in the past without being recognised.
The findings were published in the journals Science Advances and Nature Communications.