地球潮汐による傾斜・ひずみと海洋潮汐について(第3報)

抄録

Oceanic influences upon the earth tidal tilts and strains observed at Barim in China, and Kamigamo, Osakayama, Kishu, Akibasan and Oura in Kinki District, Japan, have been estimated for the wave O₁ in the same way as in previous reports. Theoretical earth tides including the oceanic influences have been compared with the observed values. The result are summarized in Tables IV and V, together with those of the wave M₂. In the tables amplitude ratios and phase differences between the observed earth tides and those calculated for the Gutenberg earth model are shown for each component of tilts and strains at the above stations. The E-W component of tilt at Barim, E-W, N-S and N61°E-S61°W components of strains at Osakayama, and N30°W-S30°E and N60°E-S60°W components of strains at Kishu are well explained by the Gutenberg earth model, and two components of tilts at Akibasan are better explained by a modified Gutenberg model with a realistic crustal structure. The discrepancies between the observed and calculated values on the other components may be attributed to several factors such as errors of calibration, shortness of analyzed records, deficiency of the sensitivity of instruments, meteorological disturbances, coupling of instruments to the ground, effects of stress concentration around observation vaults, crustal heterogeneity, and errors of estimation of the indirect effects.