Application of a method to assess coastal hazard: the cliffs of the Sorrento Peninsula and Capri (southern Italy)

A systematic method to quantify, rank and map the distribution of hazards is applied to the coastal cliffs of the Sorrento Peninsula and Capri (Campania, southern Italy). For such cliffs, which have previously been characterized in terms of types and processes, and therefore compartmentalized, the predisposition to a particular hazard (or indicator), based on its nature, magnitude and recurrence, is evaluated by assigning a code: the higher the predisposition, the higher the code for each compartment. Moreover, hazards can influence one another, and the number of such interactions indicates the seriousness of each hazard, to which a weighting is assigned. By comparing each code in a specific compartment using an interaction matrix, which takes the weighting into consideration, we have calculated a resultant, which is the overall hazard for the compartment. This resultant can also be expressed cartographically. In this application six primary hazards (parameters) are considered: cliff retreat, riverine flooding, storms, landslides, seismicity and volcanism, and man-made structures. The last is the most hazardous parameter, which is weighted highly, owing to its extensive influence on the other hazards. In contrast, riverine flooding and seismicity and volcanism are the least interactive.