Inner core super-rotation

Inner core super-rotation is a hypothesized eastward rotation of the inner core of Earth relative to its mantle, for a net rotation rate that is usually faster than Earth as a whole. A 1995 model of Earth's dynamo proposed super-rotations of up to 3 degrees per year; the following year, a seismic study claimed that the proposal was supported by observed discrepancies in the time that p-waves take to travel through the inner and outer core. However, the hypothesis of super-rotation is disputed in the later seismic studies.

The seismic support of inner core super-rotations was based on the changes of seismic waves that transversed inside the inner core and free oscillations of Earth. The results are inconsistent between the studies. A localized temporal change of the inner core surface was discovered in 2006 and the temporal change of inner core surface also provided an explanation to the seismic evidence that was attributed to the hypothesis of inner core super-rotations. Recent studies indicated that a super-rotation of the inner core is inconsistent with the seismic data. Some studies proposed both the inner core super-rotation and localized temporal changes of inner core surface co-exist to consistently explain the seismic data, but other studies indicated that localized temporal changes of the inner core surface alone are enough to explain the seismic data.