Surface deformation analysis in Northeast Italy by using PS-InSAR and GNSS data

Geodetic data play a crucial role in the detection of surface deformation related to active tectonic processes. The present study aimed to investigate the Northeastern Italian sector, characterized by a convergent regime due to the NNW-ward motion of the Adria microplate towards the Eurasian plate, at a rate of ~ 2mm/yr. N-S shortening is accommodated by fold and thrust systems in the Alpine chain and buried below the Friuli-Venetian plain sediments. We used InSAR and GNSS data respectively in 2015-2019 and 2000-2020 time interval to estimate the surface kinematics and deformation pattern of the area. We processed the SAR images acquired by the European satellites Sentinel 1A/B from ascending and descending tracks by using the Stanford Method for Persistent Scatterers (StaMPS). A post-processing of the resulting Line-Of-Sight (LOS) deformation time series was carried out by applying a spatial-temporal filter and calibrating using the velocities provided by GNSS stations. Finally, the post-processed ascending and descending LOS measurements were combined to solve for the vertical and horizontal (east-west) deformation components. We observed a positive vertical signal toward the Alps, in the northern region of Veneto and Friuli-Venezia Giulia. Moreover, we observed a significant negative vertical signal located in the plain and in the coastal zones due to the subsidence that strongly affects these areas. Horizontal velocities with rate of 1-2 mm/yr are observed close to main tectonic structures, especially in the eastern and the northwestern sector of the study area, where GNSS data reveal higher shortening rate.