A landslide in Greenland triggered a mega-tsunami that “shook the Earth” for nine days in September 2023. The seismic event was picked up by earthquake sensors worldwide, but it was so unique that researchers initially could not determine its cause, The Guardian reported.
“We were like, ‘Oh wow, this signal is still coming in. This is completely different to an earthquake’,” Stephen Hicks at University College London was quoted as saying by the New Scientist. “We called it an unidentified seismic object, or USO.”
“It kept appearing - every 90 seconds for nine days,” Hicks added. Earthquake signals usually last only minutes, but this USO kept repeating every 90 seconds for nine days.
The mystery of the USO has now been solved, thanks to the efforts of 70 people from 15 different countries.
Here’s what happened
The short answer is that in September 2023, a landslide occurred in Greenland where a mountainside collapsed and carried glacial ice with it. This landslide triggered a 200-meter-high wave that became trapped in the narrow fjord, causing ongoing vibrations that were picked up as a repeated seismic signal by global sensors.
Scientists say that landslides like these are becoming more common with climate change, which is causing the glaciers supporting Greenland’s mountains to melt.
The research
{{/usCountry}}Scientists say that landslides like these are becoming more common with climate change, which is causing the glaciers supporting Greenland’s mountains to melt.
The research
{{/usCountry}}A team of scientists across the world, along with the Danish Navy, investigated the incident. Their findings have been published in the journal Science, reported BBC.
The team pinned down the source of the signal to Dickson Fjord in East Greenland.
Dr Kristian Svennevig from the Geological Survey of Denmark and Greenland, the lead author of the report, said: “When we set out on this scientific adventure, everybody was puzzled and no one had the faintest idea what caused this signal.
“It was far longer and simpler than earthquake signals, which usually last minutes or hours, and was labelled as a USO – an unidentified seismic object.
“It was also an extraordinary event because it is the first giant landslide and tsunami we have recorded in east Greenland at all. It definitely shows east Greenland is coming online when it comes to landslides,” Dr Svennevig explained.