geosciences Article The 2013–2018 Matese and Beneventano Seismic Sequences (Central–Southern Apennines): New Constraints on the Hypocentral Depth Determination Brando Trionfera 1, Alberto Frepoli 2,*, Gaetano De Luca 2, Pasquale De Gori 2 and Carlo Doglioni 1,2 1 Dipartimento Scienze della Terra, Università La Sapienza, 00185 Roma, Italy;
[email protected] (B.T.);
[email protected] (C.D.) 2 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00185 Roma, Italy;
[email protected] (G.D.L.);
[email protected] (P.D.G.) * Correspondence:
[email protected] Received: 19 November 2019; Accepted: 24 December 2019; Published: 30 December 2019 Abstract: The Matese and Beneventano areas coincide with the transition from the central to the southern Apennines and are characterized by both SW- and NE-dipping normal faulting seismogenic structures, responsible for the large historical earthquakes. We studied the Matese and Beneventano seismicity by means of high-precision locations of earthquakes spanning from 29 December 2013 to 4 September 2018. Events were located by using all of the available data from temporary and permanent stations in the area and a 1D computed velocity model, inverting the dataset with the Velest code. For events M > 2.8 we used P- and S-waves arrival times of the strong motion stations located in the study area. A constant value of 1.83 for Vp/Vs was computed with a modified Wadati method. The dataset consists of 2378 earthquakes, 18,715 P- and 12,295 S-wave arrival times. We computed 55 new fault plane solutions. The mechanisms show predominantly normal fault movements, with T-axis trends oriented NE–SW.