GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.3 GNGTS 2023 New estimates of the contribution of Glacial Isostatic Adjustment to sea-level variations and vertical land movements in the Northern Adriatic Sea and in the Venetian Lagoon F. Linsalata 1 , D. Melini 2 , G. Spada 1 1 Dipartimento di Fisica e Astronomia (DIFA), Alma Mater Studiorum Università di Bologna, Italy 2 Istituto Nazionale di Geofisica e Vulcanologia (INGV), Roma, Italy The present-day sea-level variations and vertical movements in the northern Adriatic Sea result from complex geodynamical, geological, and meteorological processes that span a wide range of time scales and result from a number of simultaneously operating mechanisms, recently illustrated by Zanchettin et al., (2021). Among these, a potentially important contribution is given by Glacial Isostatic Adjustment (GIA), the process arising from the interactions between the cryosphere, the solid Earth and the oceans in response to the melting of ice loads. While sea-level signals caused by tectonic forces may exhibit a complex spatial and temporal variability (Carminati and Di Donato, 1999; Stocchi and Spada, 2007), those associated with GIA are characterized by smooth, long-wavelength patterns (Clark et al., 1978; Clark and Lingle, 1979). However, Spada and Melini (2021) have shown that the regional variability of GIA in the Mediterranean is significant in spite of the relatively small extent of basin, demanding the adoption of high-resolution models. Although the GIA contribution in northern Adriatic Sea has been discussed several times, significant uncertainties still exist, especially related with the extent and chronology of the Würm Alpine ice-sheet that, due to its proximity to the coasts of the northern Adriatic, is still affecting the isostatic equilibrium in these particular areas. This was first pointed out by Gudmundsson (1994), who studied the post-glacial rebound process occurring in the Swiss Alps and the surrounding regions. Furthermore, regional-scale rheological heterogeneities are another contribution to uncertainties in GIA models in the Mediterranean, as first pointed out by Lambeck and Purcell (2005) and reevaluated recently by Spada and Melini (2021). Following the work of Gudmundsson (1994), Stocchi at al., (2005) estimated the effects of melting of the Alpine ice sheet, including relative sea level and geodetic signals focusing on the GIA effects in the Po plain and along the coasts of the Adriatic Sea, extending results by Carminati and Di