GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 1.2 131 interpretation of the 29 May episode requires the activation of three different fault segments and a block roto-translation of the Mirandola anticline. In particular, the performed analysis permitted (i) to detect the active seismogenic structures responsible for the observed ground deformation, (ii) to evaluate the impact of the regional tectonic constraints on the modulation of the retrieved deformation field, and (iii) to provide a detailed characterization of the rock failure mechanisms. L ’ Aquila 2009 earthquake. We investigate the earthquake by exploiting ENVISAT DInSAR and GPS measurements and an independently generated fault model. We show that our modelling approach allows us to reproduce the coseismic surface displacement, including its significant asymmetric pattern, as shown by the very good fit between the modelled ground deformations and the geodetic measurements (Fig. 2). Our model permits to investigate the coseismic stress and strain field changes, their relationships with the surrounding geological structures; moreover, it highlights the very good correlation with the seismicity spatial distribution. The retrieved stress field changes show different maxima and in detail, the main event hypocenter is localized in a region of high-gradient strain field changes, while a deeper volumetric dilatation lobe involves the largest aftershock zone. From these findings we argue that the AQE hanging wall downward movement along the steep portion of PFS might have been modulated by the underlying basal detachment; on the other hand, the coseismic eastward motion of the PFS footwall might have triggered further slip on the OS, thus releasing the largest aftershock on an independent source. Amatrice 2016 earthquake. We investigate the ground deformation and source geometry of the 2016 Amatrice earthquake by exploiting ALOS2 and Sentinel-1 coseismic DInSAR measurements. They reveal two NNW-SSE striking deformation lobes, which could be the effect of two distinct faults or the rupture propagation of a single fault. We examine both cases through a single and a double dislocation planar source. Subsequently, we extend our analysis by applying a FE approach jointly exploiting DInSAR measurements and an independent structurally-constrained fault model. Our inversion shows that the coseismic deformation partitioned on the two Northern Gorzano and Redentore-Vettoretto faults (NGF and RVF) which, at the hypocentral depth (8 km), merge into a single WSW-dipping surface (Fig. 3). Fig. 1 - RADARSAT-2 DInSAR measurements and modelled LOS displacement for the two analyzed main seismic events. The FE model setup is showed.