Key Points
- A landslide in Greenland last year caused the Earth to vibrate for nine days.
- A year later, researchers have attributed the seismic event to climate change-induced temperature increases.
- Landslides "are increasing due to climate change" scientist Amelie Meyer told SBS News.
A large landslide in an uninhabited part of Greenland triggered a mega-tsunami last year.
As an estimated 25 million cubic metres of rock and ice avalanched into the Dickson Fjord, it generated waves that initially reached heights of 200m, with the average wave being around 110m.
But what followed was considerably stronger — causing the Earth to vibrate for nine days.
Researchers were initially baffled by what caused the seismic event. A year later, scientists say they're now able to explain what happened.
A seismic hum
In September 2023, seismometers around the world began to detect a seismic signal of 10.88 millihertz originating from East Greenland.
It reportedly appeared every 90 seconds for nine days.
An investigation began with the Danish military — and evolved to include experts from 15 different countries.
As reported this week in the academic journal Science, a team of 68 scientists from 40 different institutions around the world have identified the source of the seismic hum.
The September mega-tsunami wave was trapped in the narrow fjord (about 38km long and 3km wide) — resonating back and forth for days.
The rock and ice avalanche crashed into the fjord at over 160km per hour, triggering a mega-tsunami that sloshed back and forth for days. Credit: Science
"The physics behind this event is simple: ice melts and can no longer support the overlaying rock," Hrvoje Tkalčić, head of geophysics at the Australian National University, told SBS News.
"The rock falls into a fjord, creating a tsunami and seiche (a standing wave lasting for nine days), which we can detect using seismometers," he said.
But while incredibly rare, this may not be the last event of its kind.
'Landslides are increasing'
Scientists in the journal have attributed climate change-induced temperature increases to large landslides occurring in polar regions.
Just 25 days after the initial event, the area experienced another landslide which further eroded the gully.
"Landslides happen a lot and are increasing due to climate change," Amelie Meyer, a senior scientist at the University of Tasmania, said.
Climate change is degrading permafrost and thinning glaciers, Dr Meyers said, increasing the frequency and severity of landslide events. Source: Getty / Galen Rowell
"The ground is no longer held together by the cold. It's not so much melting but the rocks are breaking down."
Meyer said the increased frequency and severity of these events should send a warning to those who enjoy outdoor activities in such areas.
"There is an increase in accidents occurring in passages that used to be safe.
"There are some parts of the summer where you would avoid these areas, but now climate change is causing many to be unsafe all year round."
