Insights Into Mount Etna December 2018 Eruption From Joint Inversion of Deformation and Gravity Data

Abstract

We present results of the joint analysis of ground deformation and superconducting gravity data encompassing Etna's December 2018 eruption. The horizontal ground deformation points to a mechanism of dike opening. Accordingly, we consider forward analytical models describing the effects of a tensile dislocation and use two data inversion approaches, based on heuristic and probabilistic methods. The observed changes can be explained assuming the intrusion of a fluid lighter than bubble‐free magma, along a dike‐like structure. However, the poor fit to the vertical deformation and the discrepancy between bulk volume increase, deduced by the data inversion (some tens of millions of m3), and volume emitted through effusive activity (∼1 × 106m3) suggest that a more complex mechanism led to the eruption, involving partial inelastic accommodation of the strain and the formation of void space through increase in the fracturing rate of the medium.