The Ata Sund Fjord in Greenland. Picture: Pixabay
A ferocious landslide in a Greenland fjord last year shook the entire planet for nine days, scientists say.
Global media outlets, like the BBC, have picked up the story of how a seismic signal last September was picked up by sensors all over the world.
The finding of investigations by international scientists and the Danish Navy were published in the journal Science.
Media reports said leading scientists investigating its origin pinpointed it to the collapse of a mountainside of rock and glacial ice that had triggered a 200m wave.
The BBC said the wave was “trapped” in the narrow fjord, moving back and forth for nine days and generating the vibrations.
Landslides like this, scientists say, are happening more frequently with climate change as glaciers that support Greenland’s mountains melt.
UCL scientist Dr Stephen Hicks, who was involved in the investigation, told the BBC that initially the signal was described as an unidentified seismic object, appearing every 90 seconds for nine days.
Scientists talking about it online were then notified by colleagues from Denmark that they had received reports of a tsunami in a remote fjord, the BBC reported.
The team used the seismic data to locate signal’s source to Dickson Fjord in East Greenland and gathered other clues, including satellite imagery and photographs of the fjord.
The researchers eventually worked out that 25 million cubic metres of rock (equivalent to 25 Empire State Buildings) had slammed into the water and caused a 200m-high ‘mega-tsunami’.
The landslide began when a 1.2km-high mountain peak collapsed into the fjord, unleashing a 200m-tall wave through the narrow waterway, other media reports said.
This wave, initially towering at 110m, created vibrations that were detected by seismometers worldwide, from the Arctic to Antarctica.
Tsunamis usually dissipate within hours in the open ocean but this wave was trapped, the BBC report said.
The team created a model that showed how, instead of dissipating, it sloshed back and forth for nine days.
Scientists say the landslide was caused by rising temperatures in Greenland, which have melted the glacier at the base of the mountain.
