INTEGRATED MODELLING OF GEOPHYSICAL OBSERVATIONS AT ETNA VOLCANO

Geodetic, gravity and magnetic field changes caused by overpressure sources in volcanic areas were computed by an integrated elastic 3-D model based on Finite Element Method (FEM). The numerical computations are focused on the modeling of a complex description of Etna volcano in order to evaluate the effect of topography and medium heterogeneities. Ground deformation, gravity and magnetic changes are investigated by solving a coupled numerical problem. Different multi-layered crustal structures constrained by seismic tomography and geological evidences were considered to evaluate the effects of topography and medium heterogeneities. Comparisons are made between analytical and numerical solutions to estimate the differences caused by these features. Our findings highlight that heterogeneity and topography engender deviations from analytical results in the geophysical changes produced by pressurized sources under elastic conditions. Hence, neglecting the complexities associated with morphology and medium properties of Etna volcano in standard analytical studies, we could obtain an inaccurate estimate of source parameters from geophysical observations. The FEM approach presented here allows for considering a picture of a fully 3D model of Etna volcano, which could advance the reliability of model-based assessments of ground deformations, gravity and magnetic observations.