A recent study published in Geophysical Research Letters documented evidence of hundreds of glacial earthquakes occurring in Antarctica, marking a significant expansion in knowledge about seismic activity in the region. Glacial earthquakes represent a distinct type of seismic event generated when large sections of ice calve from glaciers and capsize upon entering the ocean, creating mechanical vibrations that travel across vast distances.
Using seismic monitoring stations positioned directly in Antarctica, researchers detected more than 360 glacier seismic events between 2010 and 2023. The majority of these events, approximately 245 occurrences, clustered near the marine terminus of the Thwaites Glacier, also known as the Doomsday Glacier due to its potential to contribute substantially to global sea-level rise. Previous detection efforts had relied on global seismic networks that may have been unable to register these events, as Antarctic glacial earthquakes appear to occur at lower magnitudes than their Greenland counterparts.
The timing of detected seismic activity at Thwaites showed a notable concentration between 2018 and 2020, coinciding with satellite observations of accelerated ice flow toward the ocean. This pattern differs from glacial earthquakes in Greenland, where seasonal air temperature variations drive fluctuations in event frequency. The research suggests that ocean conditions play a significant role in triggering these events at Thwaites, though the specific mechanisms remain incompletely understood.
A secondary cluster of seismic detections near Pine Island Glacier presented additional research questions, as these events occurred 60 to 80 kilometers inland from the coast, making capsizing icebergs an unlikely cause. These anomalous detections warrant further investigation.
The findings carry implications for assessing future sea-level rise projections. Understanding the mechanisms driving glacial earthquakes at Thwaites and the broader stability of marine-terminating glaciers could help resolve current uncertainties in long-term sea-level rise forecasts spanning multiple centuries.
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