A Rare Type of Earthquake Emerges in Antarctica
Scientists have identified hundreds of previously undetected glacial earthquakes in Antarctica, revealing a hidden source of seismic activity linked to the continent’s most unstable glaciers. Glacial earthquakes are a distinct class of seismic events that occur when massive icebergs break away from the front of a glacier and capsize into the ocean. As these towering blocks of ice collide with the glacier itself, they generate powerful ground vibrations that can travel thousands of kilometers.
Unlike typical earthquakes, glacial earthquakes do not produce high frequency seismic waves. This makes them difficult to detect using standard global monitoring systems, which rely heavily on those signals. Because of this limitation, glacial earthquakes were only identified relatively recently, despite decades of global seismic observation.
Until now, only a small number of such events had been confirmed in Antarctica. New research based on data from seismic stations located directly on the continent has uncovered evidence of more than 360 glacier related seismic events, many of which were previously unknown. The findings significantly expand scientific understanding of how Antarctic glaciers interact with the ocean and how those interactions may influence future sea level rise.
Thwaites Glacier as a Seismic Hotspot
The majority of the newly detected events were concentrated near the ocean facing edge of Thwaites Glacier, often referred to as the Doomsday Glacier because of its potential impact on global sea levels. If this glacier were to collapse completely, it could trigger a dramatic rise in sea levels worldwide.
Roughly two thirds of the identified glacial earthquakes occurred near Thwaites, strongly suggesting that they were caused by large icebergs calving and overturning at the glacier’s marine terminus. This area is already known to be one of the most dynamic and vulnerable regions of the Antarctic ice sheet.
What makes these findings particularly important is that the pattern of glacial earthquakes at Thwaites differs from what has been observed in Greenland. In Greenland, glacial earthquakes tend to follow a seasonal rhythm, peaking during warmer periods when surface melting accelerates ice flow. At Thwaites, however, the most intense period of seismic activity coincided with a phase of accelerated ice tongue movement toward the sea, confirmed independently by satellite data.
This suggests that ocean conditions, rather than air temperature alone, may play a critical role in destabilizing marine terminating glaciers in Antarctica. Understanding these ocean driven processes is now seen as a priority for predicting how quickly glaciers like Thwaites could contribute to rising sea levels.
A Second Cluster Raises New Questions
In addition to Thwaites, a second cluster of glacial seismic events was detected near Pine Island Glacier, another major contributor to Antarctic ice loss. However, these events were located far inland, well away from the glacier’s ocean front. Their distance from the calving zone suggests they were not caused by capsizing icebergs.
The origin of these inland events remains unclear. They may be linked to internal ice deformation, interactions between ice and bedrock, or other poorly understood processes occurring beneath the ice sheet. Their consistent location and repeated occurrence indicate that they are not random noise, but a genuine geophysical phenomenon requiring further investigation.
Together, the two clusters highlight the complexity of Antarctic glacier dynamics. While iceberg calving explains many of the detected earthquakes, it does not account for all of them. This complexity reinforces the idea that Antarctica’s ice sheet is responding to a combination of forces, including ocean pressure, ice flow acceleration, and interactions with the underlying ground.
Why These Discoveries Matter
The detection of widespread glacial earthquakes in Antarctica has major implications for climate science and sea level projections. These seismic signals provide a new way to monitor glacier behavior in near real time, offering insight into how fast ice is moving and how frequently large calving events occur.
Because traditional measurements of glacier stability rely heavily on satellite imagery and surface observations, glacial earthquakes add an important subsurface perspective. They reveal mechanical stress and motion that may not be visible from above, especially in remote and harsh environments.
Better understanding the relationship between ocean conditions and glacier instability could help reduce uncertainty in long term sea level forecasts. At present, projections for future sea level rise vary widely, in part because scientists lack detailed knowledge of how quickly key glaciers might fail.
By linking seismic activity to changes in glacier flow, researchers gain a powerful new tool for assessing risk. The findings suggest that short term shifts in ocean state can have immediate and measurable effects on glacier stability. As monitoring networks improve, glacial earthquakes may become a critical early warning signal for rapid ice loss.
Antarctica’s ice sheet holds enough frozen water to reshape coastlines across the globe. The discovery of hidden seismic activity beneath its glaciers underscores how much remains unknown and how urgently scientists must refine their understanding of this fragile system.
