Open AccessNon‐Linear Anelasticity and the Free Oscillations of the Earth
Author(s) -
Todoeschuck J. P.,
Crossley D. J.
Publication year - 1988
Publication title -
geophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0952-4592
DOI - 10.1111/j.1365-246x.1988.tb00471.x
Subject(s) - superposition principle , perturbation (astronomy) , physics , amplitude , earth model , geophysics , linear response theory , frequency spectrum , classical mechanics , geology , statistical physics , quantum mechanics , optics , condensed matter physics , spectrum analyzer
Summary It has sometimes been suggested that anelasticity at seismic frequencies in the mantle might be non‐linear. Such non‐linearity, depending on its form, could have several consequences for the free oscillations of the Earth. Both Q and the associated frequency shift can become functions of amplitude and therefore of time. the frequency shifts can lift degeneracies. the failure of superposition can cause modes to interact, so that the motion depends upon the spectrum of modes. We present a scheme based on time‐dependent perturbation theory for calculating these effects with some simple illustrations.