Rockfall is an impendent phenomenon present in many slopes throughout the world (Hoek, 2007; Chen et al., 2009). rockfalls range from small cobbles to large boulders hundreds of cubic meters in size, and travel at speeds ranging from few to tens of meters per second. Although the relatively small size of a rock block these falls are a major cause of landslide fatalities particularly along roads and characterized by high energy and mobility. Their dynamic processes are dominated by spatially and temporally distributed attributes, such as detachment conditions, geometry features and mechanical properties (static and dynamic friction, roughness, rolling resistance, restitution characteristics and fragmentation ratio) of both rock blocks and slopes (Agliardi and Crosta, 2003). Human activities on a rock slope are exposed to this incident; so the revelation of zones free of rockfall is of major significance. Minor rockfalls affect most of the rock slopes, whereas large rockfalls affect only great rock slopes with geological conditions favorable to instability (Rouiller et al., 1998). At mountainous areas where the rockfall hazard increases, the slope and rock properties controlling the initiation and behaviour of rockfalls vary widely. Studies of rockfalls are usually based on field surveys, and the hazard is estimated either by susceptibility to failure or by the calculation of a safety factor derived from rock mechanics models (Hoek and Bray, 1981; Ayala Cardeco et al., 2003, Coe and Harp (2007) indicate that rockfall travel distance on rock slopes is analyzed from empirical models. Several differences between rockfalls and other types of landslides for susceptibility analysis can be found: (i) runout is very different (generally related to block size); (ii) trace of block movement, especially the older ones, are generally absent; and (iii) at commonly used scales, the blocks from rockfall cannot be cartographically displayed (Ayala-Cardeco et al., 2003). This article introduces a methodology to evaluate the susceptibility of minor rockfall of a road located on steep caldera slopes upstream Athinios port, in the internal rim of a submarine caldera on the Santorini Island complex, and is based on geological, geomorphological parameters, structural analysis, rockfall maximum runout of rock blocks by adopting the empirical model of “reach angle” and rockfall events. The accuracy of the empirical model verified with experimental rockfall carried out on the slope. The compilation of the abovementioned parameters led to rockfall susceptibility map through GIS environment and allows us to construct several protection meters.