Hundreds of elusive glacial earthquakes have been detected in Antarctica between 2010 and 2023, primarily concentrated at the ocean end of the Thwaites Glacier, according to a study published in Geophysical Research Letters. While Greenland’s ice sheet routinely generates massive seismic events that register globally, detecting these ice-driven quakes in the southern hemisphere has long challenged scientists relying on worldwide monitoring networks.
How Glacial Earthquakes Differ From Traditional Seismic Sources
A glacial earthquake forms when tall, thin icebergs snap off the edge of a glacier and crash into the sea. As these massive blocks of ice capsize, they collide violently with the parent glacier, generating strong mechanical ground vibrations known as seismic waves that travel thousands of kilometers. Unlike tectonic earthquakes, volcanic eruptions, or nuclear explosions, these events generate no high-frequency seismic waves. That absence of high frequencies explains why researchers missed them for decades even as standard seismic monitoring advanced.
Mapping Antarctica’s Ice-Driven Seismic Activity
Direct evidence of Antarctic glacial earthquakes remained scarce because global seismic stations often fail to capture lower-magnitude events originating in the southern ice sheet. To solve this, researchers deployed seismic stations directly inside Antarctica. That local search uncovered more than 360 previously uncatalogued glacier seismic events spread across two distinct clusters near the Thwaites and Pine Island glaciers, which stand as Antarctica’s largest contributors to rising sea levels.
Did You Know? The largest glacial earthquakes detected in Greenland reach a magnitude comparable to the nuclear tests conducted by North Korea over the past two decades.
Seismic Shifts at the Doomsday Glacier
Thwaites Glacier, frequently dubbed the Doomsday Glacier, holds enough ice to raise global sea levels by roughly 3 meters if it collapses entirely. Out of the 362 seismic events detected in the recent study, 245 occurred near the marine terminus of Thwaites, marking them as probable glacial earthquakes caused by capsizing icebergs. Unlike Greenland’s ice sheet, where events peak predictably in late summer due to warm air temperatures, the strongest seismic activity at Thwaites between 2010 and 2023 occurred between 2018 and 2020. Satellite observations independently confirmed that this prolific earthquake period coincided with an accelerated flow of the glacier’s ice tongue toward the open ocean.
Frequently Asked Questions
What causes a glacial earthquake?
They are triggered when tall, thin icebergs break off from the edge of a glacier, capsize in the water, and crash violently against the parent ice mass.
Why were Antarctic glacial earthquakes discovered only recently?
Glacial earthquakes lack high-frequency seismic waves, and those occurring in Antarctica are often too small to register clearly on worldwide monitoring networks without local seismic stations.
How much could sea levels rise if Thwaites Glacier collapses?
According to scientific estimates, a complete collapse of the Thwaites Glacier would drive global sea levels up by about 3 meters.
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