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.

Source: Wikipedia — Inner core super-rotation (CC BY-SA 4.0)