Scientists have found hundreds of hidden earthquakes under the Doomsday Glacier

Under the Antarctic Thwaites Glacier, often referred to as the "Doomsday Glacier," scientists have discovered hundreds of previously unknown earthquakes. Most of them are not related to the movement of tectonic plates, but to the chipping and flipping of giant icebergs at the edge of the glacier. The study showed that the surge in such activity coincided with the period when Thwaites began to move faster towards the ocean.

According to the researchers, such data will help to better understand the processes of destruction of one of the most unstable glaciers in Antarctica and more accurately assess future sea level rise. What exactly scientists have discovered and why the Thwaites Glacier is considered one of the most dangerous on the planet — in the material of Izvestia.

Hundreds of unknown earthquakes have been discovered under the ice

The study is published in the journal Geophysical Research Letters (GRL). A scientist from the Australian National University analyzed records of seismic stations collected in Antarctica from 2010 to 2023, and discovered 362 previously unknown seismic events that were missing from existing catalogs. The analysis has significantly expanded the understanding of the activity of glaciers in West Antarctica.

The largest cluster included 245 earthquakes recorded near the sea edge of the Thwaites Glacier. The researcher concluded that most of them relate to the so-called glacial earthquakes. They occur not due to the movement of lithospheric plates, but when large icebergs break off: after separation, the ice blocks turn over in the water and hit the edge of the glacier, creating powerful seismic waves.

The peculiarity of such events is that they are almost not accompanied by high-frequency fluctuations typical of ordinary earthquakes. Because of this, they have long been difficult to detect using traditional seismic monitoring methods. So far, such processes have been well studied mainly in Greenland, whereas there have been significantly fewer confirmed observations for Antarctica.

According to the publication, until now, direct evidence of glacial earthquakes caused by the overturning of icebergs in Antarctica has remained elusive.

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Why is Thwaites called the "Doomsday Glacier"

Thwaites Glacier is located in West Antarctica and is considered one of the largest and most rapidly changing glaciers on the planet. Its width reaches about 120 km, and the area is comparable to the territory of Great Britain. For several decades now, satellite observations have recorded that the glacier is gradually accelerating towards the sea and losing mass.

The unofficial name "Doomsday Glacier" has emerged due to its potential impact on global ocean levels. If Thwaites collapses completely, global sea levels could rise by about 65 cm. However, the main problem lies in the fact that the glacier serves as a kind of support for a significant part of the West Antarctic Ice Sheet.

Scientists compare it to a cork holding huge masses of ice inside a continent: if Thwaites loses its stability, neighboring glaciers may also begin to drain into the ocean faster. In this case, the long-term contribution of West Antarctica to sea level rise may exceed 3 m.

At the same time, experts emphasize that the name "Doomsday glacier" does not mean an inevitable catastrophe in the near future. Even the most unfavorable scenarios develop over decades or centuries. Nevertheless, it is Thwaites' behavior that is considered one of the main sources of uncertainty in predicting future sea level rise.

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Why are scientists worried about him?

Researchers are interested not only in the size of the glacier, but also in the fact that the changes taking place in it may reflect processes affecting the entire West Antarctica. In recent years, scientists have repeatedly recorded an acceleration of the Thwaites movement, a reduction in the area of the floating ice shelf and increased melting of its base under the influence of relatively warm ocean water.

A new study has shown another pattern: the peak of glacial earthquakes occurred in the period 2018-2020, when satellite observations also recorded an acceleration of the glacier's movement towards the ocean. According to the author of the work, this may indicate a close relationship between the state of the ocean, the chipping of icebergs and the stability of the glacier.

In addition to Thwaites, the researcher discovered another large cluster of seismic events near the Pine Island glacier. However, these earthquakes occurred much further from the ice breaking line — about 60-80 km away, so their origin remains unclear. The authors suggest that there may be completely different processes behind them.

The results indicate a short-term effect of ocean conditions on the stability of glaciers ending in the sea. The researchers argue that this issue requires further study to assess the glacier's future contribution to sea level rise.

Earthquakes will help predict sea level rise

The authors of the work believe that glacial earthquakes can become a new tool for monitoring changes in Antarctica. Since such events occur during the chipping of large icebergs, they allow you to track the processes of glacier destruction in almost real time, even in hard-to-reach areas of the continent.

According to the researchers, combining seismic data with satellite observations will allow for a better understanding of how glaciers respond to changes in ocean temperature and climate. This is especially important for glaciers ending in the sea, as they are currently making one of the largest contributions to global sea level rise.

The authors emphasize that the discovery of hundreds of hidden earthquakes by itself does not mean that the destruction of the glacier has accelerated dramatically or has become inevitable. However, the results show that the processes at its boundary with the ocean are much more complex than previously assumed, which means that existing models of glacier change may require clarification.

In the future, scientists plan to use such observations to more accurately assess how quickly Antarctica's largest glaciers will change in the face of ongoing climate warming. Such data is needed to improve forecasts of sea level rise and assess possible impacts on coastal regions around the world.