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ESA Maps New Low in South Atlantic Anomaly as Weak Zone Expands

High-precision Swarm readings link the shifting magnetic trough to processes at the core–mantle boundary.

Overview

  • A peer-reviewed analysis in Physics of the Earth and Planetary Interiors using 2014–2025 ESA Swarm data confirms the anomaly has grown to cover about 1% more of Earth’s surface.
  • The local magnetic intensity in the region has fallen from roughly 24,000 to about 22,000 nanoteslas in recent decades while the center drifts east at around 20 km per year.
  • Researchers identify a new magnetic minimum southwest of Africa that indicates the weak zone could evolve into separate cells.
  • Low-Earth-orbit satellites traversing the area face higher radiation exposure with elevated risks of single-event upsets, prompting mitigation measures and operational adjustments.
  • Companion observations show a weakening strong-field region over Canada and a strengthening one over Siberia, and experts emphasize no immediate danger to people at the surface.