GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 1.2 173 Methods and data. Inedited subsurface data are herein presented, consisting of a series of unpublished seismic reflection profiles and wells gathered for the study area. In this work, we use a new dataset of 2D seismic reflection profiles kindly provided by ENI s.p.a. The entire study area is therefore covered by integration of 97 seismic reflection profiles and 4 boreholes (Varoni, Campotosto, Antrodoco, Amandola) (Fig. 2a). The dataset encompasses a heterogeneous amount of stack and time- migrated seismic reflection lines characterized by a variable quality, due to several factors. We loaded and interpreted the entire dataset by using the Midland software MoveTM, accurately accounting for crooked paths and for datum time-shifts. Finally, we also included additional data encompassing geological sections and maps, a Digital Terrain Model (DTM) of the area and earthquakes hypocenters distribution from Chiaraluce et al. (2017) covering the period of interest (24 August 2016 - 30 December 2016). Such workflow enabled us to build an integrated pseudo-three- dimensional project of the study area (Fig. 2b), providing a novel and multidisciplinary working environment for the imaging of the geologic subsurface structures. In this work, we show a portion of the entire dataset, presenting a 2D subsurface model built up along one representative geological transect (Fig. 2b), intercepting the area struck by the mainshock Mw 6.5. The seismic profiles belonging to this ENE-WSW transect show subsurface structures down to a maximum depth of 5 s (twt), corresponding to 10–12 km, reconstructing a novel geological model across the Norcia-Mt.Vettore area (Fig. 1). Results and conclusions. The results of this work provide constraints regarding some critical points discussed in literature for the central Apennines affected by the last 2016-2017 seismic sequence. The main features investigated are: the depth of the basement, the trajectory of the main thrust and normal faults, the role of the inherited structures on the seismogenic faults and the seismogenic layer involved into the seismicity. The seismic signature of the main thrusts is not evident on the data, but the attitude of the deep reflectors within the tectonic units (top of carbonates and Marne a Fucoidi Fm.) indicates Fig. 2 - a) Location map of the seismic reflection profiles and wells used in this study; b) close-up of the seismic reflection profiles used to construct the geological cross-section (black line), organized into a 3D working project.