Rapid geomagnetic changes inferred from Earth observations and numerical simulations

Extreme variations in Earth's magnetic field direction offer insights into the geodynamo. Paleomagnetic studies have reported rapid directional changes (up to 1º yr⁻¹), but their relation to core processes remains unclear. This study shows strong agreement between the amplitudes and latitude ranges of extreme directional changes in geodynamo simulations and a recent observational field model (GGF100k) spanning the past 100 kyrs. Maximum rates reach ~10° yr⁻¹, typically during field strength decreases, much faster than current changes. Analysis suggests these changes are linked to reversed flux movement across the core surface. Future searches should focus on low latitudes.

Christopher J. Davies, Catherine G. Constable