Glacial earthquakes are a special type of earthquake generated in cold, icy regions. First discovered in the northern hemisphere more than 20 years ago, these quakes occur when huge chunks of ice fall from glaciers into the sea.
Until now, only a very few have been found in the Antarctic. In a study published in Geophysical Research Letters, I present evidence for hundreds of these quakes in Antarctica between 2010 and 2023, mostly at the ocean end of the Thwaites Glacier – the so-called Doomsday Glacier that could send sea levels rising rapidly if it were to collapse.A recent discoveryA glacial earthquake is created when tall, thin icebergs fall off the end of a glacier into the ocean.
When these icebergs capsize, they clash violently with the “mother” glacier. The clash generates strong mechanical ground vibrations, or seismic waves, that propagate thousands of kilometres from the origin.
What makes glacial earthquakes unique is that they do not generate any high-frequency seismic waves. These waves play a vital role in the detection and location of typical seismic sources, such as earthquakes, volcanoes and nuclear explosions.
Due to this difference, glacial earthquakes were only discovered relatively recently, despite other seismic sources having been documented routinely for several decades.Varying with the seasonsMost glacial earthquakes detected so far have been located near the ends of glaciers in Greenland, the largest ice cap in the northern hemisphere.
