Some problems on the analysis of the earth tides.

Abstract

The spectral structure of the earth tides which have been observed during one year by an Askania gravimeter at Kyoto, and that of the corresponding theoretical tides on a rigid earth, were compared to determine the tidal factor of gravity and the phase lag with a high precision. A band-pass filter that has dominant responses only for semidiurnal or diurnal frequencies was applied to both of the tidal functions, to eliminate the effects of drift and of contamination from other constituents. Variations in the two tidal parameters during the period were also examined, extracting only M[2] or O[1] wave by the use of a narrow Gaussian filter. These results show long-period fluctuations with several months, suggesting a limit for discussions on elastic and anelastic behavior of the earth.