Geophysicist Thanh-Son Pham of the Australian National University has identified more than 360 previously unknown seismic events beneath Antarctica between 2010 and 2023, with 245 of them clustered near the ocean-facing edge of Thwaites Glacier, published in Geophysical Research Letters.
The tremors are "glacial earthquakes" — violent vibrations produced when tall, thin icebergs break off the glacier, capsize in the water, and slam back into the ice they came from. Because these quakes generate no high-frequency seismic waves, they had gone undetected by global monitoring networks; Pham's team instead used data from seismic stations positioned directly on the Antarctic continent.
Activity peaked between 2018 and 2020, a period that also saw Thwaites' ice tongue accelerate toward the sea, suggesting changing ocean conditions may be destabilizing the glacier from below. Thwaites alone holds enough ice to raise global sea levels by roughly 3 meters if it collapses entirely, making the new seismic record a potential early-warning tool for tracking its decline.