Fred Richards^1,2, Sophie Coulson¹, Jacqueline Austermann³, Mark J Hoggard^1,3 and Jerry X Mitrovica¹, (1)Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA, United States, (2)Imperial College London, Earth Science and Engineering, London, United Kingdom, (3)Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, United States