Post-glacial readjustment, sea-level variations, subsidence and erosion along Italian coasts

Ongoing sea-level variations and vertical land movements, measured by tide gauges as well as by continuous GPS stations in Italy, stem from several factors acting on different spatiotemporal scales. Contrary to tectonic and anthropogenic effects, characterized by a heterogeneous signal, the melting of the late-Pleistocene ice sheets results in a smooth long-wavelength pattern of sea-level variation and vertical deformation across the Mediterranean, mostly driven by the melt water load. In this work, we define upper and lower bounds of the effects of glacial isostatic adjustment (GIA) on current sea-level variations and vertical movements along the coasts of Italy. For various mantle viscosity profiles, we explore to what extent the spatial variability of the observed rates may be attributed to a delayed isostatic recovery of both solid Earth and geoid. We find that long-wavelength patterns of sea level change are tuned by GIA, and that the coastal retreat in Italy is broadly correlated with the expected present-day rates of sea-level variations.