Activity: Talk or presentation › Talk or presentation at a conference
Vertical GPS velocities show that due to glacial isostatic adjustment (GIA) regions that were formerly covered with ice sheets are currently uplifting, while surrounding areas subside. Present-day horizontal surface motion is mostly ob-served to point away from the former ice load. However, in some regions horizontal velocities point toward the former ice load, for instance at GPS sites near the Ross Sea Embayment (RSE). These observations could point to the importance of a transition from low to high upper mantle viscosity that is thought to underlie the Transantarctic Mountains. The effect of lateral viscosity transitions on the direction of horizontal motion is difficult to understand, partially because the dependence of horizontal motion on homogeneous mantle viscosity has not been systematically studied.