An analysis of tidal strain observations from the United States of America: I. The laterally homogeneous tide

Abstract

abstract Tidal strain observations from seven observatories in the continental United States have been analyzed and the results compared with the tide predicted for a radially stratified earth model. Included in the predicted tide are the effects of ocean-tide loading for all of the major oceans. We find that on average the load strains contribute 44 per cent of the total M2 tidal strain and 13 per cent of the total O1 tidal strain. The differences between the predictions of the radially stratified earth model and the observations are significant. We conclude that: (1) Love numbers deduced from most strain observations are not representative of average earth properties. (2) The phase of the areal strain is neither independent of the tidal loading nor of the local geological structure. Hence, to use such phase observations as a measure of the anelastic properties of the Earth is incorrect.