GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 Fig. 1: a) Location of the study site in the Italian peninsula (red square) with the highlighted Tiber river (light blue) and its upper basin (blue shaded area). b) Main geological formations and tectonic units and faults at the study site. c) Distribution of both the 33 continuous GNSS stations and the 45 seismic stations employed for the analysis, together with the Tiber upper-basin hydrological control area. Observations For the geodetic observations, we apply variational Bayesian Independent Component Analysis onto the GNSS time series in order to discriminate the main sources of deformation in the study area (Serpelloni et al. 2018). Fig. 2 shows the temporal signal and spatial coefficients corresponding to the independent component with the largest deformation signal. It reveals a remarkable seasonal behaviour and a uniform spatial response in the vertical direction, with displacement amplitudes of the order of ~15 mm. Other identified sources of deformation in the region (not shown) include the respective tectonic signals associated to the post-seismic deformation following the 2016 central Italy seismic sequence and to a seismic swarm occurred at the ATF from the end of 2013 throughout 2014.