Hundreds of Hidden 'Glacial Earthquakes' Found at Antarctica's Doomsday Glacier

A new study has found evidence of hundreds of previously undetected "glacial earthquakes" in Antarctica, most of them near Thwaites Glacier, known as the Doomsday Glacier because its complete collapse could raise global sea levels by 3 metres. The study was published in the journal Geophysical Research Letters.

Glacial earthquakes are caused when tall, thin icebergs break off the end of a glacier, fall into the ocean and capsize, striking the parent glacier hard enough to send seismic waves travelling thousands of kilometres. They carry no high-frequency seismic waves, unlike typical earthquakes, which is why they went undetected by global monitoring networks for decades; they were first discovered in Greenland more than 20 years ago.

Using seismic stations located in Antarctica itself rather than the worldwide network, the researcher found more than 360 glacial earthquakes between 2010 and 2023, most not previously included in any earthquake catalogue. The events fell into two clusters, near Thwaites and Pine Island glaciers — the largest sources of sea-level rise from Antarctica — with 245 of the 362 events located near the marine end of Thwaites.

The most active period of quakes at Thwaites, between 2018 and 2020, coincided with a satellite-confirmed speed-up of the glacier's ice tongue toward the sea, rather than the seasonal pattern of warm air temperatures that drives Greenland's glacial earthquakes. A second, smaller cluster was found 60 to 80 kilometres from the waterline near Pine Island Glacier, too far inland to be explained by capsizing icebergs, and the cause remains unclear.