Crustal loading near Great Salt Lake, Utah -: art. no. 1111

[1] Two sites of the BARGEN GPS network are located 30 km south of Great Salt Lake (GSL). Lake-level records since mid-1996 indicate seasonal water elevation variations of 0.3 m amplitude superimposed on a roughly "decadal'' feature of amplitude similar to0.6 m. Using an elastic Green's function and a simplified load geometry for GSL, we calculate that these variations translate into radial crustal loading signals of +/-0.5 mm (seasonal) and +/-1 mm (decadal). The horizontal loading signals are a factor of similar to2 smaller. Despite the small size of the expected loading signals, we conclude that we can observe them using GPS time series for the coordinates of these two sites. The observed amplitudes of the variations agree with the predicted decadal variations to <0.5 mm. The observed annual variations, however, disagree; this difference may be caused by some combination of local precipitation-induced site motion, unmodeled loading from other nearby sources, errors in the GSL model, and atmospheric errors.