On the free oscillation of the Earth's inner core

The effects of rotation and of the finite radius of the outer core are taken into account in the calculations of the period of the free gravitational oscillation of the inner core, which was first considered by Slichter (1961). Quantitative results are derived in the case of the polar mode. The differences in the periods of the equatorial modes are discussed qualitatively. It is suggested that oscillations of the inner core of detectable amplitude may be excited by fluid motions in the outer core.