GNGTS 2016 - Atti del 35° Convegno Nazionale

198 GNGTS 2016 S essione 1.2 References Anderlini L., E. Serpelloni, M. E. Belardinelli (2016), Creep and Locking of a low-angle normal fault: Insights from the Altotiberina fault in the Northern Apennines (Italy), Geophys. Res. Lett., 43 Barchi M., G. Minelli, G. Pialli (1998), The CROP 03 Profile: a synthesis of results on deep structures of the Northern Apennines, Mem. Soc. Geol. Ita., 52, 383–400. Bennett R. A., et al. (2012), Syn-convergent extension observed using the RETREAT GPS network, Northern Apennines, Italy, J. Geophys. Res., 117, B04408 Berardino P., G. Fornaro, R. Lanari, E. Sansosti (2002), A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms, IEEE Trans. Geosci. Remote Sens., 40, 2375–2383 Devoti R., F. Riguzzi, M. Cuffaro, C. Doglioni (2008), New GPS constraints on the kinematics of the Apennine subduction, Earth Planet. Sci. Lett., 273(1-2):163-174 Montone P, M. T. Mariucci (2016), The new release of the Italian contemporary stress map, Geophys. J. Int., 205 (3), 1525-1531. Lavecchia G., P. Boncio, N. Creati (2003), A lithospheric-scale seismogenic thrust in central Italy, Journal of Geodynamics, 36, 79–94 Pondrelli S., S. Salimbeni, G. Ekstrom, A. Morelli, P. Gasperini, G. Vannucci (2006), The Italian CMT dataset from 1977 to the present, Phys. Earth Planet. Inter., 159, 286–303 Rovida, A., R. Camassi, P. Gasperini, M. Stucchi (2011), CPTI11, the 2011 version of the Parametric Catalogue of Italian Earthquakes, Ist. Naz. di Geofis. e Vulcan., Milano, Bologna. Savage J.C. (1983) A dislocation model of strain accumulation and release at a subduction zone, J. Geophys. Res.: Solid Earth, 88, 4984–4996. Serpelloni E., C. Faccenna, G. Spada, D. Dong, S.D.P. Williams (2013), Vertical GPS ground motion rates in the Euro- Mediterranean region: New evidence of velocity gradients at different spatial scales along the Nubia-Eurasia plate boundary, J. Geophys. Res. Solid Earth, 118, 6003–6024 Tape C., P. Musé, M. Simons, D. Dong, F. Webb (2009), Multiscale estimation of GPS velocity fields, Geophys. J. Int., 179, 945–971 Tectonic features of a crucial sector of the central Mediterranean including northeastern Sicily and southern Calabria G. Barberi, C. Musumeci, D. Patanè, L. Scarfì Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania - Osservatorio Etneo, Catania, Italy Introduction. The analysis of the seismological features performed in this study provides an essential contribution to constrain the present-day geodynamic processes occurring in an important sector of the central Mediterranean area, including the northeastern Sicily and the southern Calabria. For this area, recent studies have shown a very complex tectonic framework, fragmented into crustal blocks separated by seismically active belts and characterized by neighboring collisional, subduction and active volcanic (Etna and Aeolian Arc) domains. In the present study, a high-quality dataset of about 3000 small-to moderate-magnitude earthquakes (1.0<ML<5.7), collected between 1999 and 2013 by a local seismic network, has been exploited for local earthquake tomography. By overlapping earthquakes distribution and velocity discontinuities, it was thus possible to outline the main tectonic structures affecting the area. Moreover, focal solutions traced in the 3D velocity model, together with available published source mechanisms from catalogues with M > 4.0, were used to resolve the current local stress field and to characterize the faulting regime. Data analysis and results. The seismic velocity models (V P , V S and V P /V S ) and the earthquake locations was carried out by exploiting the special features of two algorithms. In particular, in a first step we computed an initial reliable crustal structure by using the program LOTOS (Koulakov, 2009), which uses a self-adapting grid geometry, based on the ray density, to reduce possible bias of the resulting models due to the grid configuration (e.g., overly large node spacing to suitably image the size of genuine anomalies). The 3D V P and V S models