A first look at the Gargano (southern Italy) seismicity as seen by the local scale OTRIONS seismic network

Abstract

OnApril 2013,alocal scale seismic network,namedOTRIONS, composed of twelve short period (1 Hz) three component seismometers, has been located in the northern part of the Apulia (Southern Italy). At each station, the acquisition systemallows the recording of data in situ and their real time transfer toa seismic laboratory located at the Dipartimento di Scienze della Terra e Geoambientali of Università di Bari "Aldo Moro". The preliminary real time detection and localization of the events is automatically realized by using the SeisComp3 software. In the first two months of data acquisition, the network recorded about one hundred low magnitude (ML<2) earthquakes. In that follows,wepresent the results of a study aimed at investigating the crustal structure of the Gargano promontory. To this aimweanalyzed the seismic events recorded in the area by the “Istituto Nazionale di Geofisica e Vulcanologia” (INGV) in the period 2006-2012 and the seismic events recorded by the OTRIONS network in the first two months of acquisition (march and april 2013). From the inversion of P and S travel times of INGV events we inferred a preliminary 3-layer Vp velocity model. The Moho is located at a depth of 27-30 km, in agreement with previous studies. A linearized inversion scheme that uses Velest (Kissling et al., 1994), allowed us to infer a 1D velocity model from the joint inversion of INGV and OTRIONS datasets of P and S travel times. On the whole, the number of earthquakes recorded by the OTRIONS seismic network is higher than 1200 in the period april,2013-march,2014.