Spatial analysis aims to determine the position of vents based on knowledge of past eruptions, the existence of structural controls on vent distribution, the characterisation of products from previous eruptions, and their spatial interrelations (Felpeto et al., 2007; Martí and Felpeto, 2010; Bartolini et al., 2013). This information will provide the basis for establishing the probability of vent opening (i.e. volcanic susceptibility) and the probability of invasion (i.e. laterally and longitudinally) by new eruptive products.
Volcanic susceptibility (Martí and Felpeto, 2010) is an essential part of spatial analysis and consists of determining the spatial distribution of future vents based on the distribution of past vents and their structural controls, as the location of a new vent will govern possible eruptive scenarios.
Two time scales have to be considered in susceptibility analyses. The first consists of long-term hazard assessment and examines the structural criteria that provide direct information on the internal structure of the volcanic field, including its past and present stress fields (Martí and Felpeto, 2010; Marzocchi et al., 2010). The second scale corresponds to the computation of volcanic susceptibility is short-term analyses (from days to a few months) during unrest episodes, and includes those structural aspects that can be inferred from volcano monitoring, as well as the results of long-term volcanic susceptibility analysis (Marzocchi et al., 2008; Sobradelo and Martí, 2013; Bartolini et al., 2016).