Eruptive mechanisms
A better understanding of the factors controlling variability in the eruptive style of an eruption is of fundamental importance to improve the comprehension of the behaviour of volcanoes and to define a criterion for hazard evaluation. The potential explosivity of a volcanic system is a function of the pre-eruptive volatile content and, more in general, of magma evolution in the last stages of ascent or in the magma chamber. Though the most explosive eruptions are often related to highly evolved magmas, basaltic explosive magmatism is also very common, since basaltic volcanoes represent more than 80% of active volcanoes on Earth.
Basaltic explosive eruptions generally occur as Hawaiian or Strombolian eruptions, or through eruptive styles with intermediate characteristics between these two end-members. However, the activity of basaltic volcanoes can sometimes show anomalous, highly explosive and dangerous scenarios. Our line of research in this field is aimed at the elaboration of multidisciplinary models of the feeding system dynamics and to define the role of evolutionary processes and ascent rates in the development of explosive activity in basaltic systems.
Our main expected goal is the identification of concurrent parameters leading to the development of variably explosive eruptive styles. Our investigations should establish a basic instrument for the prediction of eruptive scenarios within a single event, such as the changing eruptive style from effusive to explosive, or short-term future events. This provides important clues for the definition of volcanic hazard in densely populated areas on our National territory and abroad where explosive basaltic volcanism occurs.
Magma storage and ascent dynamics
The complex structure of stratovolcanoes makes magmas able to interact with the crust and differentiate at several levels of the feeding system during their ascent from the source zone towards the surface. Thus, it is often difficult to assess the relative role of evolutionary processes such as fractional crystallization, crustal assimilation and magma mixing between variously evolved magmas. Whole rock compositions that we study through classic geochemical approaches are potentially due to the superimposition of several of these processes, so that tracking magma evolution might become a hard task.
Magma genesis and metasomatism
Several authors ascertained the significant role of metasomatic enrichment processes for generating mineralogical and chemical heterogeneity in the mantle.
Such an occurrence can be strictly localized, originating small- to intermediate-scale heterogeneity in the upper mantle, but if large volumes of fluids or melts migrate, vast regions of the mantle can be affected by metasomatism, leading to large-scale lithologic heterogeneity. These processes are mainly ruled by the migration of LILE- and LREE-carrying fluids or silicate melts, which permeate and vein the pre-existing mantle.