The Doomsday Glacier is at the center of a striking new discovery hidden deep under Antarctica’s frozen edge. For the first time, scientists have found hundreds of special earthquakes at some of the continent’s most fragile glaciers.
A powerful new look beneath Antarctica’s ice
These events, known as glacial earthquakes, occur when tall, thin icebergs break off from glaciers and flip over in the ocean. As they topple, they crash into the remaining ice with huge force, sending strong vibrations into the ground.
These quakes are not like normal earthquakes. They fail to create the high-frequency waves that scientists usually use to detect shaking from earthquakes, volcanoes, or even nuclear tests. Because of this, glacial earthquakes have stayed hidden for many years. They were first found in the northern hemisphere more than two decades ago, especially in Greenland. But in Antarctica, where the world’s largest ice sheet sits, they have been extremely hard to detect.
A new study has now changed that. Using seismic instruments placed directly on the icy continent, researchers discovered more than 360 of these special events between 2010 and 2023. Most happened near one place: the ocean edge of the Thwaites Glacier — often called the Doomsday Glacier because of how much sea level it could raise if it collapses.
The hidden rumblings of the Doomsday Glacier
The Thwaites Glacier is one of the most rapidly changing glaciers on Earth. If it were to fall apart fully, it could raise global sea levels by around 3 meters. That is why scientists watch it closely. But until now, they did not know how often giant icebergs were falling from its edge and creating powerful quakes.
In the new study, about two-thirds of all detected events were located near the floating end of Thwaites. Scientists believe these events happen when icebergs suddenly break off and flip as they enter the sea. As the icebergs crash into the water, their force shakes the ground strongly enough for sensors to detect it hundreds or even thousands of kilometers away.
While glacial earthquakes in Greenland usually occur more often in late summer, the Antarctica quakes do not follow the same pattern. At Thwaites, the most active period was from 2018 to 2020. This spike matched a time when the glacier’s ice tongue sped up as it slid toward the ocean. This faster flow was also observed by satellites.
The quickening of the ice tongue may have been linked to changes in the nearby ocean. Warmer waters can melt ice from below, weaken the edges, and allow large blocks to break off more easily. But the exact role the ocean played in this sudden speed-up is still not fully understood.
These findings show that ocean conditions can influence how fast and how often glaciers lose ice. The impact appears to happen over short periods, not just over decades. This makes it important for scientists to understand what triggers these iceberg falls and how they affect the glacier’s stability.
Researchers also found a second cluster of seismic events near the Pine Island Glacier, another major source of ice loss in Antarctica. But these events occurred far from the water’s edge — between 60 and 80 kilometers inland. They were not linked to iceberg capsizing. Their cause is still unclear and will need more research.
Why these discoveries matter for understanding Antarctica
The discovery of hundreds of glacial earthquakes in Antarctica opens a new window into how glaciers behave. These hidden vibrations act like signals from deep inside the ice. They help scientists understand how ice breaks, how glaciers move, and how the ocean interacts with frozen land.
Until now, most attempts to find such events in Antarctica used seismic stations around the world. But if the quakes were smaller than those seen in Greenland, global networks could not pick them up. Researchers used sensors placed directly on the continent to capture signals that they would have missed otherwise.
Glacial earthquakes near Thwaites are especially important because the glacier sits on a bed of soft ground that slopes downward inland. This shape makes it more likely to retreat quickly if its front becomes unstable. Detecting the shakes caused by falling icebergs gives experts another tool to watch the glacier’s changes in real time.
The newly detected quakes also highlight the strong influence of the ocean. When the ice tongue of Thwaites sped up between 2018 and 2020, iceberg-related quakes surged. This suggests that the ocean may play a more immediate role in glacier behavior than previously known. Understanding these connections can help researchers map the hidden forces affecting Antarctica’s most vulnerable ice.
At Pine Island Glacier, the inland cluster remains a mystery. These events occurred too far from the coastline for iceberg capsizing to cause them. They may come from ice cracking, deep movement, or other processes that researchers have not yet clearly identified. Scientists need to monitor them further to figure out what drives them.
The signals recorded between 2010 and 2023 show that Antarctica’s glaciers are far more active than earlier data suggested. By listening to these deep ice vibrations, scientists are uncovering new layers of information that were previously impossible to detect.
