New insights on the 2012-2013 uplift episode at Fernandina Volcano (Galapagos)

We analysed the 2012-2013 uplift episode at Fernandina Volcano (Galapagos) through the inverse modeling of Differential Synthetic Aperture Radar Interferometry (DInSAR) ground displacement field. The post-processing analysis of COSMO-SkyMed satellite data revealed that the uplift phenomenon can be divided in three distinctive intervals in which the displacement maintains a nearly constant deformation rate. We used both ascending and descending acquisitions to evaluate the vertical and the horizontal E-W components of the displacement field. The vertical displacement is strongly limited in a narrow region around the caldera rim, where the circumferential fissures that border the summit platform are localized and the E-W component of the horizontal displacement affects the external volcano flanks, up to the apron region. Moreover, we exploited the DInSAR time-series by performing a cross-correlation analysis: both vertical and E-W cross-correlated maps confirm that the observed uplift episode is related to the existence of a single active source, approximated as a pipe-like source. Indeed, our results, obtained through an inverse modeling approach by investigating different type of analytic sources, suggest the existence of an over pressurized pipe-like source, with a slight dip toward SE and located beneath the summit caldera region. The modeled geodetic source could represent the shallower part of an extended and deeper magmatic reservoir.