A recent study has revealed an unexpected shift that happened beneath the Pacific Ocean in 2010. Using decades of satellite and ground-based magnetic field data, researchers tracked a dramatic shift in the movement of the iron-rich fluid located roughly 2,200 km beneath Earth’s surface.

The study suggests that Earth’s deep interior could be more dynamic and unpredictable than previously believed. Researchers say the discovery could improve understanding of how Earth’s magnetic field evolves and how processes deep inside the planet may be interconnected.

The flow reversal

Earth’s magnetic field is generated by the movement of electrically conducting molten iron inside the liquid outer core. Scientists have long believed that the core’s large-scale flow patterns remained relatively stable over decades, generally moving westward.

However, the study found that a large region of molten iron beneath the equatorial Pacific suddenly reversed direction in 2010, shifting from westward to strong eastward movement.

Researchers reconstructed the change using satellite and ground observations collected between 1997 and 2025, including data from European Space Agency missions Swarm and CryoSat, as well as Germany’s CHAMP and Denmark’s Ørsted satellites.

“The large-scale flow reversal beneath the Pacific raises new questions about the behavior of Earth’s deep interior. Scientists now want to understand whether the reversal represents a short-lived fluctuation, part of a repeating oscillation, or a new stable equilibrium for core circulation,” said Frederik Dahl Madsen, a lead author on the study.

Satellites helped scientists peer deep inside Earth

Launched in 2013, the Swarm satellite constellation carries highly sensitive magnetometers designed to map Earth’s magnetic field with exceptional precision.

By operating in coordinated orbits, the satellites can isolate magnetic signals generated deep inside Earth from interference caused by oceans, the crust, ionosphere, and magnetosphere.

These measurements enabled scientists to identify sudden changes linked to the Pacific reversal and a geomagnetic disturbance known as the 2017 geomagnetic jerk. Researchers also detected wave-like accelerations and rapidly changing flow structures hidden within earlier datasets.

, “Although Swarm was launched after the dramatic reversal event of 2010, it has provided high-precision data that tell us about Earth’s inner core in the period that followed,” said ESA Swarm Mission Manager Anja Stromme.

Understanding Earth’s magnetic shield

Although these processes occur far below Earth’s surface and pose no direct threat to life or climate, they play a critical role in protecting the planet. Earth’s magnetic field shields the atmosphere and technological systems from harmful charged particles emitted by the sun.

Scientists say studying changes in the core could improve understanding of navigation systems, spacecraft operations, and near-Earth space weather.

ESA Swarm Mission Scientist Elisabetta Iorfida noted, “This study shows that regional changes can emerge rapidly within just a decade.

“The findings may also help scientists investigate possible interactions between Earth’s outer core, inner core, lower mantle and, therefore, give more insights into core-mantle boundary, which is a critical region for the deep Earth dynamics,” she said.

The study was published in the Journal of Studies of Earth’s Deep Interior.