Open AccessTorsional Oscillations of the Earth
Author(s) -
Takeuchi H.
Publication year - 1937
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1937.tb07117.x
Subject(s) - mantle (geology) , earth model , rigidity (electromagnetism) , homogeneous , inner core , geology , outer core , core–mantle boundary , core (optical fiber) , geophysics , physics , statistical physics , quantum mechanics , optics
Summary Making use of the variational calculus method developed in a previous paper, we calculate the free periods of torsional oscillations for two Earth models. In the Model, the Earth is assumed to be composed of homogeneous mantle and core. In the Model 2, we use the mantle structure model by Jeffreys and Bullen. In order to see the dependence of the periods on the core rigidity, we calculate the periods when the core is fluid or perfectly rigid. In the fluid core model, we work out the periods when the coupling between the mantle and core is perfect or zero. The present study will show that in order to get useful information on the rigidity of the core or the strength of coupling between the mantle and core by this kind of study, we must make the observations of free periods with an accuracy of several ten seconds.