Crustal displacements due to continental water loading

The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displace- ments (ARM) have root-mean-square (RMS) values for 1994- 1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for hori- zontal deformation. We compare ArM with observed Global Positioning System (GPS) heights (Aro) (which include ad- justments to remove estimated effects of atmospheric pres- sure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the Aro time series are ad- justed by ArM, their variances are reduced, on average, by an amount equal to the variance of the ArM. Of the Aro time series exhibiting a strong annual signal, more than half