VOLCANBOX uses QVAST (Bartolini et al. (2013) to calculate volcanic susceptibility. This is a free tool designed to generate user-friendly quantitative assessments of volcanic susceptibility. If different input data sets (structural elements) are available for the area, QVAST computes the total susceptibility map by assigning different weights to each of the corresponding probabilistic density functions, which are then combined via a weighted sum and modelled in a non-homogeneous Poisson process. Examples of the application of this tool can be found in Becerril et al. (2014) and Bartolini et al. (2014 a, b).
Field structural data including the location of eruptive vents, and structural alignments (fractures, faults, cone alignments and dykes), as well as the current regional and local stress fields constitute the main input parameters for the calculation of volcanic susceptibility, which will be provided in probabilities. It is important to always evaluate the importance of each data according to its relative age, as the most recent features should give the best idea of the current stress field.
When monitoring data generated during an unrest phase are available, the QVAST tool can also be used to update susceptibility maps in short-term analyses. In fact, seismicity and surface deformation are good indicators of magma movement. As unrest evolves these precursory signals help to fix with greater accuracy the probable vent location by inferring the position of magma below the surface.