The focus of this work is the assessment of the hazards related to the presence of pyroclastic deposits in the densely populated Vesuvian area, evaluating, in particular, the hydrogeological and the volcanic hazard. Particular attention was paid to the largest of the Vesuvian towns, Torre del Greco, because its territory is the most affected by these two typologies of hazard. The project is divided in three parts: (i) a detailed mapping of the south-western sector of Vesuvius, integrating stratigraphic and petrologic data with archaeological and historical information; (ii) a study of the medieval eruptive activity of the Somma-Vesuvius volcano, an important period of the Vesuvius activity, which has been, definitely, under-researched, in which we focused on the tephra fallout deposits, integrating newly collected data with those already available in literature; (iii) the assessment of the hazard connected to the Volcaniclastic Flows.