Oceanic load tides in the western United States

The solid Earth’s deformation response to surface loading by ocean tides depends on the material properties of Earth’s interior. Comparisons of observed and predicted oceanic load tides can therefore shed new light on the structure of the crust and mantle. Recent advances in satellite geodesy, including altimetry and Global Navigation Satellite Systems (GNSS), have improved the accuracy and spatial resolution of ocean-tide models as well as the ability to measure precisely three-dimensional surface displacements caused by ocean tidal loading. Here, we investigate oceanic load tides in the western United States using measurements of surface displacement made by a dense array of GNSS stations in the Network of the Americas (NOTA). Dominant tidal harmonics from three frequency bands are considered (M₂, O₁, M_f). We compare the empirical load-tide estimates with predictions of surface displacements made by the LoadDef software package (Martens et al., 2019), with the goal of refining models for Earth’s (an)elastic and density structure through the crust and upper mantle of the western US.