Exploring the Kinematic Structure of Mount Etna Volcano (Sicily, Italy) by Deformation Analysis and Gravity Gradient Tensors

Abstract

Ground deformation monitoring of active volcanoes is used routinely to determine phases of volcano unrest and can provide insights in the evolving plumbing system of a volcano and the influence local tectonics structures have on the volcano tectonic evolution of the volcanic edifice. Volcanic deformation analysis can be performed using velocity and direction measurements of the ground surface using Global Navigation Satellite System (GNSS). In this study, we perform two-dimensional deformation analyses of pre‑ and post‑eruptive phases with the scope of determining the strain before and after an eruptive phase at Mt. Etna Volcano (southern Italy) during 2004‑2006. In order to do so, we analyse the GNSS displacement data from Mt. Etna between 2004‑2005 and 2005‑2006 using the dedicated SSPX software. The extention, dilation and rotation maps of the study area were determined. The contraction and volumetric decrease concomitant the 2004‑2005 effusive eruptive period and extension and volumetric increase for the 2005‑2006 data series were observed. The deformation on the northeast part of Mt. Etna Volcano, which showed different characteristics with respect to its surroundings, was thought to be conditioned by the dynamic of the Pernicana fault system. Additionally, Complete Spherical Bouguer (CSB) gravity anomaly and the gravity gradient tensors were calculated giving insight on the subsurface structures of Mt. Etna Volcano and its surroundings.