Analysis of secular polar motion and continental drift

The secular latitude variations of the five ILS stations of Mizusawa, Kitab, Carloforte, Gaithersburg and Ukiah were analyzed taking into account the recent continental drift theory. Using Le Pichon's 1968 reconstruction, the rate of rotation was computed from the astronomical data, fixing the pole of rotation by Le Pichon's determination. The most reasonable solution was obtained considering Mizusawa, Kitab and Carloforte lying on the Eurasia plate, the two American stations as one on the American plate (Gaithersburg) and the other on the North—East Pacific plate (Ukiah). The resulting relative rate between the Euro-American plates is found to be 0".0028/year and between the American—Pacific plates 0".0032/ years, or about 1°,3/10⁶ years and in excellent agreement with the plate tectonic theory. Luxembourg Meeting of the “Journées Luxembourgeoises de Géodynamique”, 1972.