X- and C-Band InSAR data to identify local effects following the 2016 Central Italy seismic sequence

Abstract

The 2016 Central Italy seismic sequence consisted of more than three months long sequence, and still on going, that produced several damages in the areas surrounding the epicenters of the earthquakes causing hundreds of victims. The surface displacement fields due to the main events occurred on August and on October respectively, were effectively constrained by means of X-, C- and Lband InSAR data. The retrieved results revealed significant deformation patterns close the Amatrice, Visso and Norcia towns showing ground subsidence values greater than 20 cm. Moreover, we also observed some local complexities in the interferometric fringes patterns, not directly attributed to the main tectonic patterns. These local effects were effectively analyzed by Cosmo-SkyMed (X-band) and Sentinel-1 (C-band) data because of their wavelength more suitable to the scale of the investigated phenomena. In particular, we detected a clear local signal along the Mount Vettore, the highest mountainous relief of the Mount Sibillini, following the Mw 6.0 Amatrice/Accumuli earthquake. It was constrained by Cosmo-SkyMed data acquired along both the ascending and descending track. In addition, a deformation pattern was observed by Sentinel-1 and Cosmo-SkyMed descending data along the already known Deepseated Gravitational Slope Deformation (DGSD) of Mt. Frascare, in the proximity of the Fiastra Lake Dam. Finally, the seismic events of October 2016 produced some interferometric fringes (with the number depending on the used frequency band) along the sector of Mount Sibillini at the eastside of Acquacanina district. Geomorphological and geological post-processing analysis allowed us to ascribe such patterns to ground displacement occurred along local effects due to gravitative and karst phenomena.