Numerical modeling of surface deformations on Mt. Vesuvius volcano (Italy) in presence of asymmmetric elastic heterogeneities

The surface displacement field at Mt. Vesuvius calculated by developing elastic asymmetric 3-D and 2-D axially symmetric finite element models is presented. The models take into account the presence of the volcanic edifice, heterogeneities of country rocks, as schematically inferred from seismic tomography, and different shapes and locations of an overpressured source. In particular, we analyze the effect on surface displacements of an asymmetric structure located below sea level underneath the crater, which is more rigid than the host rocks. We tackle the problem by first developing tractable axisymmetric models, to establish some general properties of the deformation field, and then more specific 3-D models. We find that, depending on source shape and location with respect to the rigid structure, the surface displacement field may show peculiar asymmetries that cannot be retrieved with axisymmetric models. Moreover, we find that the effect of the rigid structure and the carbonate basement is to focus the deformation field around the summit area of the volcano. (C) 2003 Elsevier B.V. All rights reserved.