Mysterious seismic event that shook the Earth for 9 days was triggered by a 200-meter-high tsunami in Greenland, researchers say

A tsunami following a landslide in a Greenland fjord caused by melting icewas responsible for a surprising seismic event last year that shook the Earth for nine days, a researcher told AFP on Friday.

According to a recent report published in the journal Science, the earthquakes recorded in September 2023 were caused by the massive wave that rocked back and forth in Dickson Fjord in remote eastern Greenland.

“What is completely unique 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 generated seismic signals, but only for a few hours and very locally. This one has been observed worldwide, all the way to Antarctica,” he said.

The phenomenon initially surprised the scientific community. They initially defined it as an “unknown seismic object,” but then 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 124 miles from the sea.

The landslide triggered a 200-meter-high mega-tsunami at its epicenter.

More than 65 kilometers away, tsunami waves over three meters high damaged a research base on the island of Ella.

“When colleagues first discovered this signal last year, it didn't look like an earthquake at all,” Stephen Hicks, a scientist with a PhD in geosciences 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 the wave lapping back and forth for nine days.

“We have never seen such a large movement of water over such a long period of time,” Hicks told BBC News.

The collapse was caused by the thinning of the glacier at the foot of the mountain, a process that was accelerated by Climate changesays the report.

“As the Arctic continues to warm, we can expect the frequency and magnitude of such events to increase in the future,” Svennevig said.

“We have no experience in dealing with an Arctic as warm as the one we are seeing now,” he added.

He stressed the need to introduce early warning systems, but noted that this is challenging in such extreme environments.