Optimal locations for GPS measurements in North America and northern Europe for constraining Glacial Isostatic Adjustment

Abstract

We determine the optimal location in North America and Fennoscandia for uplift rate or tangential velocity data that will be useful for addressing ice sheet thickness, lithospheric thickness, lateral viscosity variation and background viscosity profile in the lower mantle. An optimal location is defined by where sensitivity lies above the current accuracy of GPS measurements. The approach here is different from previous studies that compute sensitivity kernels for viscosity perturbations within a small volume of the mantle. The advantage of the current approach is that the total effect of 3-D lateral heterogeneity in the mantle related to seismic tomography of the whole mantle can be studied. The sensitivity of ice sheet models and lateral lithospheric thickness variations are also studied. Our results show that in North America more permanent GPS stations are needed in northern Canada especially in a region west of the Hudson Bay until the Rocky Mountains. In Fennoscandia, the GPS network is almost adequate, but it should be extended to the last known GIA-affected areas in the Russian part of East Europe and to Central Europe. In addition, we show locations of prospective GPS sites that are sensitive to all four parameters (ice sheet thickness, lithospheric thickness, lateral viscosity variation and background viscosity profile in the lower mantle) and locations that are sensitive to only one, two or three parameters. Thus, the results are useful for the inversion of one individual parameter or for the separation of the effects of two or more parameters in inversions. © 2010 The Authors Journal compilation © 2010 RAS.