Tsunamigenic potential of unstable masses in the Gulf of Pozzuoli, Campi Flegrei, Italy

Abstract. Campi Flegrei, one of the most monitored and studied volcanic areas in the world, has recently attracted significant attention due to the reactivation of its peculiar activity, consisting of small earthquakes, geothermal phenomena and slow subsidence/rapid uplift cycles, known as bradyseism. While much of the research and of the attention focuses on potential eruptions or other volcanic-related activities, the potential hazard posed by gravitational instabilities has received little consideration. The interaction of the destabilized masses with water can trigger tsunamis, potentially affecting the whole coastline of the Gulf of Pozzuoli, which lies above the Campi Flegrei caldera. Moving from the limited available geomorphological studies of the area, a set of four landslide-tsunami scenarios (one subaerial and three submarine sources) are reconstructed. These are simulated through a sequence of numerical codes, accounting for all the phases of the tsunami process, providing insights into the distribution of tsunami energy and identifying the most affected coastal stretches. Additionally, the study explores the influence of dispersion effects in the tsunami propagation and the occurrence of resonance effects in some minor inlets of the Gulf, emphasizing the importance of accounting for complex and non-linear coastal processes when treating landslide-generated tsunamis.