GNGTS 2016 - Atti del 35° Convegno Nazionale

196 GNGTS 2016 S essione 1.2 progressively increasing the radius of influence around GPS stations from 0.1 to 3 km and evaluating the misfit. In this analysis, only GPS sites with time series longer than 6 years (and without acquisition holes, see Fig. 1C) have been considered. Before the correction of InSAR velocities, the total RMS is 1.3 mm/yr for GPS sites used to estimate the ramp correction. After the ramp removal, the RMS is reduced to 0.5 mm/yr and the two final datasets show a better agreement (Fig. 1D) overall for the entire InSAR and GPS velocity fields, with the exclusion of the edges of the InSAR frame. Vertical interseismic deformation and dislocation modeling. Vertical ground motion rates can provide fundamental constraints in the study of dip-slip faults (in extensional and compressional tectonic settings). Being InSAR observations mainly sensitive to the vertical deformation component, we have extrapolated the vertical deformation rates from InSAR measurements removing the horizontal signal. This latter has been estimated from a continuous Fig. 1 – A (top left) - GPS 3D velocity field referred to the same Reference Point (square) of the InSAR dataset; B (top right) - InSAR long-term velocities along LOS direction from ENVISAT ascending acquisitions and GPS measurements projected along the same sight satellite direction; C (bottom left) - Planar ramp signal removed from InSAR data, estimated using the reported GPS sites; D (bottom right) - Corrected InSAR measurements and GPS data projected in LOS direction. A B C D