POTENTIAL EFFECTS OF ONGOING POSTGLACIAL ADJUSTMENT ON VERY LONG BASE-LINE INTERFEROMETRY MEASUREMENTS

Very long baseline interferometry (VLBI) has the potential to estimate the rates of postglacial adjustment across northern North America. By employing glacial isostatic adjustment theory, the radial rates of uplift or subsidence were computed at five VLBI sites. The expected rates of baseline extension or reduction between these sites and seven static sites (with respect to postglacial adjustment) were estimated. These first-order estimates may act as a guide in organizing a VLBI network to measure ongoing postglacial adjustment and help determine how many years would be required to observe the deglaciation signal. Ideally, using a network which includes sites in the region of maximum postglacial uplift and sites in the southern United States, this signal should be observed in approximately 10 years of annual measurements.