GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 Fig. 1: Epicentral map of 12 earthquakes with ML ≥ 3.5 occurred in the first hours after the mainshock and revised by the BSI (orange symbols) compared to the epicenters of the same events localized by the INGV seismic surveillance room (blue symbols). The stars (blue and orange) are the events with ML=5.7 and ML=5.2 (color code is the same). Fig. 2: Hypocenter location formal errors for parameters of longitude, latitude and depth. Color code is the same as Fig. 1. BSI are formal hypocentral errors from BSI analysis and INGV-SR are formal hypocentral errors from the INGV seismic surveillance room analysis The velocity model issue Events location in the Adriatic Sea suffers from the lack of a specific velocity model for the seismic sequence area. The use of inadequate velocity parameters during the location process can introduce systematic errors, which may result in incorrect seismotectonic interpretations. We therefore built and tested different velocity models from both available geophysical data and our inversion of the velocity structure using the arrival time readings revised by the BSI working group. In order to define deterministic 1D models suitable for earthquake location (Vp and Vp/Vs), we integrated sonic logs from local deep wells (ViDEPI Project, 2005) with literature data that include: seismic commercial profiles, deep seismic refraction surveys, the CROP03 crustal profile, Receiver Function and regional seismic tomography models, Vp/Vs reference values for mid- and lower-crustal crystalline rocks (Coward et al., 1999; Ponziani et al., 1995; Lavecchia et al., 2003; Spada et al., 2013; Di Stefano et al., 2009, Christiansen and Mooney, 1993).