Estimates of vertical crustal motion derived from differences of TOPEX/POSEIDON and tide gauge sea level measurements

We have computed estimates of the rate of vertical crustal motion from differences of sea level measurements made by the TOPEX/POSEIDON radar altimeter and a globally distributed network of 114 tide gauges. A rigorous error analysis was performed which suggests the accuracy of the estimated vertical rates is approximately 1-2 mm/year for roughly half of the tide gauges, which is sufficiently accurate to detect a variety of geophysical phenomena. While only a cursory analysis of the estimated crustal motion rates was performed, we observed many interesting phenomena including significant uplift at volcanic islands in the Pacific and uplift of 7-9 mm/year along the southwest coast of Alaska. The results reported here will be useful in a variety of geophysical studies, as well as for validation of similar estimates of vertical crustal motion provided by precise geodetic techniques such as SLR, DORIS, GPS, and VLBI.