A Consideration on Earth Tidal Change of Gravity

Abstract

Gravimetric observations with the portable Worden gravimeter were made at three stations in our country to obtain accurate values for the earth tidal factor of gravity (G) and to detect, if possible, the local characters of these values. The observation period was respectively one month for each station, and the three stations were specially selected from the stand-point of diversity in conditions with regard to the supposed effect by ocean tides and subterranean structure. Judging from the observation results the G-values observed at three stations are generally well in accord with each other, but, if the numerals in the third figure of the G-valuc obtained can be assumed to have any significance, it should be said that the problem of the local character of the G-value remained unsolved and awaits the future investigation. The effect by ocean tides upon the G-value is discussed somewhat in detail, and the highly sensitive gravity variometer of double bifilar suspension type is also introduced.