A tsunami that was triggered by a landslide in a fjord in Greenland, caused by melting icewas responsible for a surprise seismic event last year that shook the Earth for nine days, a researcher told AFP on Friday.
According to a report recently published in the scientific journal Science, the tremors recorded in September 2023 came from the huge wave rocking back and forth in Dicksonfjord in remote eastern Greenland.
“The completely unique thing about this event is how long the seismic signal lasted and how constant the frequency was,” one of the report’s authors, Kristian Svennevig of the Geological Survey of Denmark and Greenland, told AFP.
“Other landslides and tsunamis have produced seismic signals, but only for a few hours and very localized. This one was detected worldwide, all the way to Antarctica,” he said.
The phenomenon initially surprised the scientific community, who first defined it as an “unidentified seismic object” but later determined that the source was the landslide.
In September 2023, 882 million cubic feet of rock and ice – a volume equivalent to 25 Empire State Buildings – fell into the fjord in the remote and uninhabited area, about 125 miles (200 kilometers) from the ocean.
The landslide caused a 200-meter-high megatsunami at the epicenter.
More than 64 kilometres away, tsunami waves measuring over three metres high damaged a research base on Ella Island.
“When colleagues first saw this signal last year, it didn’t look like an earthquake at all,” Stephen Hicks, a scientist with a PhD in earth sciences who was involved in the report, told BBC News. “It kept appearing — every 90 seconds for nine days.”
According to BBC News, a group of scientists began discussing the strange signal on an online chat platform.
The team created a model that showed how the wave sloshed back and forth for nine days.
“We’ve never seen such a large displacement of water over such a long period of time,” Hicks told BBC News.
The collapse was caused by thinning of the glacier at the foot of the mountain, a process accelerated by Climate changeaccording to the report.
“As the Arctic continues to warm, we can expect such events to become more frequent and larger in size in the future,” Svennevig said.
“We have no experience of dealing with an Arctic region that is as warm as we are seeing now,” he added.
He stressed the need to put in place early warning systems, but noted that this is challenging in such extreme circumstances.
