Scientists Detect Unexpected Eastward Flow Shift in Earth's Pacific Core Region

Satellite measurements reveal that a large body of molten iron beneath the Pacific Ocean reversed from a weak westward drift to a strong eastward surge around 2010, a change whose cause remains unknown.

A comprehensive analysis of magnetic data from ESA's Swarm, CryoSat, CHAMP and Ørsted missions indicates that the molten iron layer about 2,200 km deep under the Pacific Ocean switched from a modest westward motion to a pronounced eastward flow in 2010. This rapid shift challenges the prior assumption that large-scale circulation in Earth's outer core is relatively steady. The eastward current reached its peak strength in the early 2010s and has been declining since 2020, raising the possibility of a transient event or a segment of a natural oscillation.

Frederik Dahl Madsen of the University of Edinburgh's School of Geosciences notes that the timing coincides with changes observed in the inner core, hinting at deeper connections. ESA's Swarm mission manager Anja Stromme highlights the value of the satellite's long-term, high-precision magnetic records for tracking such deep-Earth dynamics. The findings improve understanding of the geodynamo that sustains Earth's protective magnetic field, which influences navigation, space-weather forecasting and technological systems.