GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.3 GNGTS 2024 We selected these points, where possible, according to the following criteria: 1. Stability of the monuments; 2. Benchmarks build during the establishment of the IGM95 networks (1993-1995); 3. Number of occupatons on the past; Unfortunately, these criteria are not always respected in partcular the second and third criteria, for example eight points (SPNT, PTDE, POZZ, MOLI, IS13, GEMO, CONS and CAMP) were built during the phase of densifcatons of the network (2000-2001) and four points have only one occupaton (VOLM, PTDE, POZZ and MOLI). Moreover we have examined the duraton of the measurement session for the old campaign, in partcular, the frst campaigns (1993) were characterised by an average of 4.5 hours measurement sessions, which decrease to 2 hours in the early 2000’s (1996,2000,2006 and 2010). In additon we have chosen same points close to same contnues GPS statons, in order to compare our results to those obtain from the permanent statons. Obviously, the IGM95 network was created for cartographic and topographic applicatons, for this reason most of the IGM95 beckmarks do not follow restrictve geodetc requirements for geophysical applicatons (duraton, stability, use of tripod, Anzidei et al. 2008), but, in our opinion, these aspects are probably compensated by their long term velocity (30 years on 2023). However, these IGM95 points were selected in order to improve the strain rate, in term of resolutons, of selected structures on the Northern Apennines and Southern Alps thrust belt, and to establish a “0 points” for the future in order to improve our knowledge about these thrust belt. The data were processed by Gamit-Globk sofware using double-diference phase observaton with ambiguity resolutons, precise orbits and adoptng the absolute phase center model for receiver and satellite antenna. The preliminary velocity feld (Fig.2) is expressed in the IRTF14 reference frame with respect to the Eurasian plate (Altamini et al., 2017). From a preliminary evaluaton, the velocity feld obtained by IGM95 sites is agree with the compressive dynamics and with that obtained by the permanent statons belong to the RING (Rete Integrata Nazionale GNSS) and FReDNet (Friuli Regional Deformaton Network) networks, managed by INGV (Isttuto Nazionale di Geofsica e Vulcanologia) and OGS (Isttuto Nazionale di Oceanografa e di Geofsica Sperimentale) respectvely in the framework of the PRIN2020 - NASA4SHA Project.