A Hidden Contributor to Rising Sea Levels
Date: August 31, 19:32
Thwaites is one of the most closely watched glaciers in Antarctica because its loss could drive major sea-level rise. A new study in Geophysical Research Letters confirms that glacial earthquakes were far more common across the continent than previously known.
Between 2010 and 2023, researchers recorded over 360 seismic events in Antarctica. Of those, 245 were located in the marine section of Thwaites Glacier, the ice stream widely known as the Doomsday Glacier.
What Drives Glacial Earthquakes
These distinct tremors happen when tall, thin icebergs detach from a glacier's edge. As the iceberg tilts, falls, and rolls over in the water, it strikes the parent glacier with enough force to generate mechanical vibrations that travel thousands of kilometers. One unusual signature is the lack of high-frequency seismic waves, which makes such events hard to detect with standard monitoring.
Most previously documented glacial earthquakes were recorded in Greenland, where they are often large and cluster in late summer. Antarctic events went unnoticed for years because their weaker signals fell below the sensitivity of global networks. Local seismic stations, however, show that Thwaites experienced its strongest phase of seismic activity from 2018 to 2020. That spike lines up with a period of faster ice-tongue movement toward the ocean, a trend also confirmed by satellite observations.
Ocean conditions, rather than seasonal shifts in air temperature, appear to be the main control on this glacier's behavior. A full collapse of Thwaites could flood the world's oceans with an additional 3 meters of sea-level rise. Researchers also identified a separate cluster of seismic events located 60–80 kilometers offshore near Pine Island Glacier, but those signals appear to have a different origin and will need further investigation.
Glacial earthquakes are a specific form of seismic activity caused when tall, thin icebergs calve from a glacier's edge and collide with the glacier while capsizing (Photo: Copernicus / ESA).
Better understanding of Antarctic glacial earthquakes could offer new insight into ice-sheet behavior and its connection to sea-level change. With the possible stakes measured in meters of global sea-level rise, expanding seismic monitoring in this remote region is becoming increasingly urgent. The findings could also lay groundwork for future research and climate adaptation planning.
Understanding the factors behind glacial behavior is crucial, especially as studies reveal the impact of land uplift on Antarctic climate. This phenomenon not only influences ice dynamics but also connects to significant historical climate shifts. For a deeper insight into how these geological changes contributed to the freezing of Antarctica before the Arctic, explore our detailed analysis here.