Onshore–Offshore Geomorphological Maps of the Southern Tyrrhenian Sea, Italy’s Naples Bay and Cilento: Consequences for the Geological Hazard

Coastal geomorphological maps generated in a GIS context in Naples Bay and the Cilento area are presented here to establish a current geomorphological framework for these two sectors of the Eastern Tyrrhenian margin. While sedimentary processes have dominated the geological evolution of the Cilento area, volcanic processes have dominated Naples Bay. The objective of this research is to present a comparison of geomorphological units vs. hazard types in Naples Bay and in the Cilento based on geomorphological maps and to demonstrate that distinct hazards are produced by various geomorphological zones. In the western sectors near Ischia and Procida, the volcanic activity has created collapsing unstable volcanic slopes, resulting in debris avalanches triggering localized tsunamis. Fluid seepage has weakened sediments in the middle canyons, causing continuous erosion and gravity flow. Water seepage has prevented limestone cliffs in the southern region from fractures and erosion, resulting in frequent rockfalls and cliff failures. The Cilento region has a diverse topography, and several natural hazards are clearly related. Depending on the type of rock, the land responds differently to water, gravity, and ocean forces. Caves and sinkholes were produced in carbonate massifs by strong rock formations and precipitation. Water was trapped in the Cilento Flysch due to its weak rock layers. Before reaching flat plains, rivers traverse tectonic valleys in coastal plains and alluvial valleys.