FEM-based inversion for heterogeneous fault mechanisms:

Abstract

A procedure, based on the Finite Element Method (FEM) for high-resolution geodetic data inversion, was developed to estimate non-uniform slip distribution during the 2002 September 22 M3.7 earthquake rupture occurring only one month before the 2002–2003 eruption of Etna volcano. FEM-generated synthetic Green’s functions are combined with an inverse algorithm to simulate deformation of the earthquake for a 3-D problem domain that takes into account heterogeneity of material properties in the volcanic edifice. The inversion of DInSAR data shows complex kinematics of the northeastern flank of theEtna volcano involving the Pernicana fault system. We detailed the coseismic shear-rupture mechanism and highlighted a tensile mechanism, never observed before, related to a first attempt of magma intrusion, which preceded the following October 26 eruption.