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Source phase shift: A new phenomenon in wave propagation due to anelasticity
Author(s) -
Buland Ray,
Yuen David A.,
Konstanty Kevin,
Widmer Rudolf
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i009p00569
Subject(s) - physics , excitation , perturbation (astronomy) , scalar (mathematics) , overtone , mechanics , toroid , phase (matter) , classical mechanics , phase transition , computational physics , condensed matter physics , quantum mechanics , mathematics , geometry , plasma , spectral line
By appealing to the correspondence principle, it is possible to compute free oscillations of an anelastic earth model directly. This formulation reveals a source phase due to anelasticity which is not predicted by first order perturbation theory. For toroidal modes, this source phase is found to be largest for source components which are proportional to the radial strain scalar rather than to the radial displacement scalar. The source phase is found to increase with overtone number. Also, large relative differences in both excitation modulus and phase with respect to an elastic model are found when the elastic excitation becomes small. This effect may be large enough to bias estimates of source properties and elastic structure.