We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano‐Mount Vettore‐Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low‐angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.
We provide a new 3-D GPS velocity field solution of the Euro-Mediterranean area computed at the Centro Nazionale Terremoti (CNT) division of the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The available raw GPS data since 1993, have been fully reprocessed by three different software and the final velocity field is obtained by combining three independent velocity solutions in a least squares sense. The input velocity solutions are treated as stochastic samples of the true velocity field by loosening the reference frame constraints in the associated variance-covariance matrix. The proposed approach allows for a fast combination of multi velocity solutions taking into account the full covariance, if available. The velocity map for the Euro-Mediterranean region will be updated and released regularly on the web portal of the National GPS Network (http://ring.gm.ingv.it). Here we show and discuss in detail the data analysis, combination scheme and results of the analysis procedure.