OBSERVATION OF THE EARTH TIDAL EXTENSION AT WALFERDANGE

Abstract

An observation of the earth tidal extension by means of extensometer which has been devised By I. Ozawa has been carried out in a gypsum mine at Walferdange, Luxemburg. The observation was begun in November, 1970. The sensitivity of the observation was in the range between 0.45 X 10^- 9 /mm and 0.61 X 10^-9/mm. The harmonic analyses have four periods whose lengths are from 30 days to 60 days. According to these analyses, the amplitude of M_2 wave and O_1 wave are (0.72-1.84) X 10^-8 and (0.43-1.07) X 10^-8, respectively. The sensitivity of the extensometer has been measured automatically with the carpaudin every other days. The differences of the phase lags between M_2 wave's KM_2 and O_1 wave's KO_1 is given as KM_2-KO_1 =41.2°-43.4° The amplitude ratio O_1/M_2 of the O_1 wave's to M2 wave's are given as 0.433~0.777. From these result, we have the ratio l/h between Shida's number and Love's one is given as 0.114±0.007. The probable values of these numbers is obtained as h= 0.75±0.06 and l=0.10±0.02. These results give the possibility that the values of Love's and the Shida's numbers are obtained directly by means of this observation far distant from the sea.