Tectonic activity and river mouth proximity drive submarine canyon retreat along Italian coasts

Active tectonics and coastal deformation predispose continental margins to submarine gravitational instability and canyon head retreat. Here we investigate the drivers of this susceptibility along the Italian coasts. We analyze a dataset of over 2700 canyon heads using a multi-parametric susceptibility model that integrates bathymetry, instrumental seismicity, uplift rates, and crustal deformation fields derived from satellite geodesy. Results indicate that proximity to river mouths and regional seismicity are primary drivers of retreat susceptibility, suggesting that such susceptibility characterizes canyon dynamics at least since the establishment of the current tectonic regime. By integrating these results with demographic exposure data, we identify priority areas for mitigating natural disasters such as landslide-generated tsunamis and coastal erosion in highly populated regions. Regional earthquakes and proximity to river mouths primarily dictate where submarine canyons retreat, posing risks to coastal populations, according to simulations of the multi-parametric susceptibility model applied to over 2,700 canyon heads around Italy.