A research team including the Geodynamics Research Center, Ehime University has measured the seismic wave velocities (P-wave and S-wave velocities) of orthopyroxene, a major component of the lunar mantle, under high-pressure and high-temperature conditions corresponding to the Moon’s interior.
By comparing the experimental data with seismic models obtained through NASA’s Apollo missions, the researchers found that the Moon’s upper mantle, at depths of approximately 40 to 740 km, may contain significantly more iron than previously believed.
This new finding provides important insights into the formation and evolution of the Earth–Moon system.
The research results were published on February 16, 2026, in Geophysical Research Letters, an academic journal in the field of Earth and planetary sciences published by John Wiley & Sons Inc.