Upper-mantle earthquakes beneath East Antarctica

Area of Science:

• Geophysics
• Seismology
• Tectonics

Background:

• Intraplate intermediate-depth earthquakes (IDEs) occur below the brittle-ductile transition, posing challenges to conventional plate tectonic explanations.
• Understanding the mechanisms behind these deep seismic events is crucial for comprehending Earth's lithospheric dynamics.

Purpose of the Study:

• To investigate the occurrence and origin of intraplate intermediate-depth earthquakes (IDEs) beneath Antarctica.
• To reconcile the existence of these IDEs with geodynamic processes and lithospheric properties.

Main Methods:

• Application of a deep-learning technique to analyze regional seismic data.
• Identification and characterization of seismic events occurring at intermediate depths.

Main Results:

• Successfully identified intraplate IDEs beneath Antarctica using advanced seismic detection.
• Attributed IDE occurrence to concentrated bending stresses from variable, thermally driven uplift along East Antarctica's edge.
• Observed an abrupt change in lithospheric strength correlating with seismic activity.

Conclusions:

• The findings support geodynamic models emphasizing the role of lithosphere-asthenosphere interactions in intraplate seismicity.
• The Antarctic ice sheet's influence on regional stress conditions highlights complex Earth system interplays.
• Advanced seismic detection may reveal IDEs are more globally prevalent than previously thought.