Lateral viscosity variations beneath Antarctica and their implications on regional rebound motions and seismotectonics

Our predicted present-day crustal motions depend strongly on the ice model chosen, with vertical motions focused on areas of former late Pleistocene ice domes. The horizontal motions are greatly affected by the earth rheology, as the horizontal flow pattern is controlled by the flow from the stiff East Antarctic cratonic root to the weaker West Antarctic mantle. Glacially-induced changes in fault stability margin are positive over much of Antarctica, indicating a seismically quiet state due to the large present-day ice sheet. At the site of the 1998 Balleny Island Earthquake (Mw=8.1), the stresses are relatively small by comparison, and interestingly become more prone to stress failure, when a three-dimensional earth model is assumed.