Repeated measurements of borehole diameter and inclination reveal the ease of ice flow. The figures to the right and below show that flow is easier or more "enhanced" for ice deposited during the Wisconsin ice age and for dirty ice at the bed of the ice sheet. Such measurements improve the theory of ice flow and help refine ice flow modeling.
Further Desirable Measurements:Continuous borehole measurements of crystal orientation within the ice can be used to test for deformed structures in the ice and measure the degree of anisotopy in the ice(Taylor, 1982). Because anisotropic ice has different rheological properties than isotropic ice, such measurements are important for ice flow modeling.
Measurements of vertical strain in the ice are also important for ice flow theory and assessments of whether the ice sheet is in a steady state.