GNGTS 2017 - 36° Convegno Nazionale

178 GNGTS 2017 S essione 1.2 Fig. 1 - Map of the study area. Awhite star indicates the epicentral location of the 1915 earthquake from the Catalogue of Italian Earthquakes (Rovida et al. , 2016). Faults modified from Cucci and Tertulliani (2015). Abbreviations: LU, Luco Fault; MA, Magnola Fault; PA, Parasano Fault; PE, Pescina Fault; SE, Serrone Fault; SS, San Sebastiano Fault; TM, Tre Monti Fault; TR, Trasacco Fault; VE, Ventrino Fault. a large interest because it affected a part of the Apennine chain characterized, from a historical perspective, by a very modest seismicity (Baratta, 1915; Rovida et al., 2016). Therefore, the event surprised a completely inadequate building stock (Oddone, 1915), causing a nearly total destruction of many villages within a large area, including the city of Avezzano, where about 10 000 casualties (90% of the population) occurred. Overall, the event caused about 30 000 fatalities. More than 230 localities suffered destructions and damage estimated greater or equal intensity VIII MCS. The epicentral area, where the destruction was the heaviest, resulted NW– SE elongated, including the Fucino basin and all the localities settled there. In the past decades, several seismogenic faults have been proposed as the source of the Fucino earthquake by means of geological, seismological, geodetic and macroseismic data (see Cucci and Tertulliani, 2015, for a complete overview). The different approaches and techniques used in these studies have led to a variety of speculations about the source mechanism and the fault location often contrasting with one another. Moreover, although it had been hypothesized that (see Castenetto and Galadini, 1999 and references therein for additional details) the dewatering of the Fucino Lake could have influenced (triggered?) the earthquake’s occurrence, no quantitative attempts to verify such a hypothesis have been proposed in literature. Hence, a numerical poroelastic model is investigated to estimate the stress changes induced by the dewatering of the Fucino lake. The numerical simulations provide a computational framework to estimate the amplitude, extent and temporal scales of the medium response. The stress changes are computed along the seismogenic source to assess likely relationship between pore pressure variations and seismicity. We performed numerous simulations in order to cover the wide spectrum of seismogenic faults proposed in literature as the source of the Fucino earthquake. Preliminary results evidence that the crustal unloading stresses related to the dewatering of the Fucino lake were not able to trigger