GNGTS 2016 - Atti del 35° Convegno Nazionale

84 GNGTS 2016 S essione A matrice allowing to simulate the evolution of the faulting processes within the best fit solution retrieval. Accordingly, we achieved (i) the active seismogenic structures responsible for the observed ground deformation, (ii) the spatial distribution of the local stress field in term of volumetric stress and strain. The inversion shows that the co-seismic displacement area was partitioned on two distinct en echelon fault planes, which at the main event hypocentral depth (8 km) merge in one single WSW-dipping surface. Slip peaks were higher along the southern half of the Vettore fault, lower along the northern half of Gorzano fault and null in the relay zone between the two faults; field evidence of co-seismic surface rupture are coherent with the reconstructed scenario. Coseismic deformation field and source modelling for the Amatrice event of August 24, 2016 by means of InSAR and CGPS data C. Tolomei, G. Pezzo, C. Bignami, S. Atzori, E. Trasatti, A. Antonioli, S. Stramondo, S. Salvi Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy Introduction. On August 24, 2016 at 1:36 UTC, a Mw 6.0 magnitude earthquake strucks a wide area in the central Apennines of Italy between the towns of Norcia and Amatrice, with the epicenter located close the village of Accumoli. The mainshock was followed by an Mw 5.4 earthquake, about one hour after the main event, and by thousands of further aftershocks along a NW-SE strip extended for about 30 km between Amatrice and Norcia. Immediately after the main event, the INGV personnel involved in the production of InSAR data for the emergency support was activated in order to measure the coseismic crustal deformation and generate a model of the seismic source to support the emergency management. The first preliminary source model was generated within 20 hours of the mainshock. We present the InSAR co-seismic deformation measurements and the seismic source model obtained by the inversion of InSAR and GPS data. In the framework of the activities carried out to provide scientific support to the national Civil Protection Department during the Amatrice earthquake, INGV was activated to generate geodetic measurements of the co-seismic deformation and models of the seismic source. A similar function is carried out by CNR/IREA, and the two institutes worked closely together to cross-validate their InSAR results. Here we present the initial results obtained by the INGV InSAR working group within 30 hours from the mainshock. SAR data. During the first week after the mainshock, several SAR images from various sensors and different frequency bands became available; from them seven interferometric pairs were processed to investigate the co-seismic displacement field. In particular, the satellite interferometric analysis exploited the Japanese satellite ALOS-2 (JAXA), operating in the L- band (wavelength of 23.6 cm), the Sentinel-1 constellation (C-band, wavelength 5.6 cm) from the European Space Agency (ESA), and the Italian COSMO-SkyMed (CSK) constellation (X- band, wavelength of 3.1 cm) developed by the Italian Space Agency (ASI). The first image pair was acquired from ALOS-2, available about 20 hours after the earthquake. Tab. 1 shows the interferometric SAR pairs used for the analysis of surface displacement along the respective radar Lines of Sight (LoS).