Open AccessA physical explanation of the static core paradox
Author(s) -
Dahlen F. A.,
Fels Stephen B.
Publication year - 1978
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1978.tb04274.x
Subject(s) - singularity , dissipation , stratification (seeds) , physics , core (optical fiber) , mechanics , classical mechanics , baroclinity , mathematical analysis , mathematics , quantum mechanics , optics , botany , dormancy , biology , seed dormancy , germination
Summary. The introduction of Rayleigh friction and Newtonian cooling into the dynamical problem of determining the excitation of the normal modes of oscillation of an earth model with a fluid core by a transient earthquake source is shown to provide a fully satisfactory resolution and a clear physical explanation of the difficulties and paradoxes which have arisen in previous treatments of the corresponding static deformation problem. The source of the previous difficulties is that the dissipation‐free limit is associated with an essential singularity in the static response, unless the stratification in the core is neutral. This singularity, in turn, exists because the eigenfrequency spectrum of any earth model with a non‐neutrally stratified core has an accumulation point at zero frequency.