Investigation of glacial isostatic adjustment in the northeast U.S. using GPS measurements

Abstract

We have been observing three-dimensional site velocities at over 60 permanent GPS stations in the northeastern U.S for the purpose of inferring mantle viscosity and thus improving current models of glacial isostatic adjustment (GIA). We estimate the upper and lower mantle viscosity by comparing radial site velocities from a subset of continuous GPS measurements with numerical GIA predictions. Our inferences are consistent with previous esti-mates obtained using different methods and data sets.