Open AccessCore Undertones with Rotation
Author(s) -
Crossley D. J.
Publication year - 1975
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1975.tb05873.x
Subject(s) - rotation (mathematics) , core (optical fiber) , physics , inertial frame of reference , deformation (meteorology) , mechanics , classical mechanics , excitation , optics , geometry , meteorology , mathematics , quantum mechanics
Summary The elastic behaviour of the Earth's liquid core at periods longer than those of the free oscillations is shown to be affected by the Earth's rotation. In particular, free spheroidal modes of the core, called undertones, exist in a core which is subadiabatic or gravitationally stable. The periods of these undertones are considerably modified by the rotation which serves to couple together modes by the excitation of torsional motion. The results indicate that the undertones will be confined within a period range 0–12 h. Other modes, related to the rotationally‐generated inertial modes known in fluid mechanics, may exist at periods greater than 12 h. Examples are given of the effect of rotation on eigenperiods of a real Earth model, including the Slichter‐type modes, and implications for the treatment of tidal deformation are discussed.