Two separate studies published in 2025 have revealed previously undetected geological and seismic activity beneath the East Antarctic Ice Sheet.
One study describes a vast, fan-shaped network of ancient basins, while another has uncovered hundreds of intermediate-depth earthquakes beneath the David Glacier. Both findings reshape our understanding of the continent's hidden geology.
Discovery of the East Antarctic Fan-Shaped Basin Province
Structure and Location
An international team led by geophysicist Egidio Armadillo of the University of Genoa has identified a massive geological structure beneath the East Antarctic Ice Sheet. Named the East Antarctic Fan-Shaped Basin Province (EAFBP), it comprises approximately 30 interconnected basins—including the Wilkes Basin, Aurora Basin, and the basin hosting Lake Vostok.
The structure is shaped like a fan, widening toward the coast in a radial pattern from a central point near the South Pole.
Formation and Tectonic History
Researchers propose that the EAFBP formed before the breakup of the supercontinent Gondwana through a process called distributed rotational extension. In this process, Earth's crust deforms outward from a fixed central point.
"This resulting zone of weakness may have influenced the separation of Antarctica and Australia, which occurred approximately 70 million years ago."
The feature may be related to a tectonic structure known as a sphenochasm. The structure likely developed over multiple phases. Researchers note that the model remains a hypothesis requiring further testing, particularly regarding the timing of deformation.
Geographic Extent and Related Features
The province extends between the Gamburtsev Subglacial Mountains and the Transantarctic Mountains. The basins are now buried under more than 1.8 miles (3 km) of ice. The formation of the province may have contributed to the uplift of the Gamburtsev Mountains to the west and helped rotate and break up the Transantarctic Mountains to the east.
Methodology
The study combined reconstructed rebound topography—simulating the landscape if the ice were removed—with radar, gravity, seismic, and magnetic data. Numerical models simulated the formation of the basins. The radial arrangement of basins, crustal thickness patterns, and topography were assessed to match rotational extension more closely than other tectonic processes.
Implications
The basins underlie approximately half of the East Antarctic Ice Sheet.
"Understanding bedrock contours improves predictions of ice movement, as tectonic processes influence glacial flow."
This finding may be relevant for studying ice sheet dynamics under climate change and provides new insight into the breakup of Gondwana and ancient mountain building.
Publication
The research was published in Nature Geoscience on June 3, 2025.
Detection of Intermediate-Depth Earthquakes Beneath David Glacier
Event and Detection
A study published in Science on May 28, 2025, used machine learning to reanalyze seismic data from 49 stations in Antarctica. The analysis revealed over 500 previously undetected earthquakes beneath David Glacier, a glacier that connects East and West Antarctica and drains approximately 4% of the East Antarctic Ice Sheet. The data were collected during two periods: 2001–2004 and 2012–2015.
Earthquake Characteristics
The earthquakes occurred at depths between 100 and 150 kilometers (60 to 90 miles), categorizing them as intermediate-depth earthquakes (deeper than 80 km). Their magnitudes ranged from 1.6 to 3.5. These are intraplate events, meaning they occurred in the middle of a tectonic plate rather than at a plate boundary.
Proposed Cause
Researchers attribute the quakes to stress at a lithospheric boundary between the cold, rigid crust and upper mantle under East Antarctica and the warmer, softer rock under West Antarctica.
Lead author Long Ho (University of Alabama) suggested that the stress may result from hot mantle pushing upward combined with the weight of the cold glacier pushing downward, causing the crust to bend.
Detection Method
A deep-learning AI system enhanced by transfer learning was used to identify P-waves and S-waves in the seismic data, enabling precise location of the earthquake events.
Significance and Open Questions
Lead author Long Ho stated that similar unnoticed earthquakes may occur in other regions, and that improved AI tools could reveal that deep intraplate earthquakes are more common than currently recognized.
Glaciologist Richard Alley (Penn State University), who was not involved in the study, commented that the apparent lack of earthquakes in Antarctica was previously attributed to insufficient analytical tools.
The detected earthquakes are not strong enough to threaten the ice sheets or ecosystem, according to Ho. However, the clustering of earthquakes only beneath David Glacier—and not along other similar lithospheric boundaries in the Transantarctic Mountains—is not fully explained by the current research, indicating that additional local factors likely contribute to the seismicity.
Future Research
Ho plans to investigate how the ice sheet's weight influences earthquake locations and how changes in the ice sheet might affect seismic activity.