GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 images, in some cases also comparing situatons documented by both pre- and post-event images. This analysis allowed for the recogniton of six key-areas (see labels in Fig. 1) where the interacton between long-term and coseismic deformaton was immediately evident, each of them being characterised by diferent tectonic and morphological features. Then, in the feld, we proceeded straight to the previously designated locatons; however, it should be noted that in each region only a limited number of measurement points, even 1 km apart from each other, were considered. This operatonal approach difers signifcantly from that used in previous seismic emergencies in Italy (Pantost et al., 2014), where measurement points were mapped extensively and practcally in a contnuous way along the fault. This strategy is motvated by the huge size of the coseismic phenomena to be mapped, as well as the limited tme and personnel available. In the feld, for ground measurements, tapes and Leica DISTO™ laser distance meters have been used, as we have digital mobile devices equipped with Rocklogger® sofware to determine the positon and orientaton of the coseismic features. Moreover, in order to map the investgated areas homogeneously and obtain detailed 3D models, we used a DJI Mini 2 drone and tablet featuring a LIDAR scanner system (Polycam®). In additon, a huge amount of photographic documentaton has been acquired by professional digital cameras. Preliminary results Overall, more than 600 structural and geomorphic data points, along with ca. 4,000 photos, were acquired in the feld on orientaton, positon and dimension of the coseismic features, including the measurements of kinematcs and ofset components. A part of this dataset was shared in real- tme with the MapLab at INGV in Rome, thanks to the tools of the GIS platorm (ArcGIS Pro®). These georeferenced data pointed to reconstruct the deformatonal patern at the local scale of the six key-areas. Morover, drone surveys provided images to reconstruct eight structure from moton (SfM) high-resoluton (5 cm/pixel) digital surface models (DSM) (Fig. 2), and relatve ortho- photomosaics. In additon, expeditous LIDAR-derived models representatve of the expression of the surface faultng in four key-areas, were also obtained by a handheld device (Fig. 3). In this way it has been possible to derive analytcal models of the coseismic mole-track along the fault trace that contain the georeferenced structural and geomorphic data. In all the investgated key-areas, lef-lateral displacements up to 5.0 m were measured and validated through the comparison of the same piercing points on pre-earthquake Google Earth® images through the same piercing points. Similarly, post-earthquake Google Earth® images allowed, at some places, to reproduce a detailed line drawing of the surface faultng in order to integrate the feld mapping. This allowed us to highlight the relatonships between coseismic surface faultng and tectonic long-term landforms (Fig. 3a).