GNGTS 2018 - 37° Convegno Nazionale

112 GNGTS 2018 S essione 1.1 The attribute computation done on the original amplitude seismic lines (Fig. 2a and Fig. 3a), has generated new seismic images allowing an increased level of interpretability. We report here the images obtained after the application of EG and PR (Fig. 2b; Fig. 3b), showing peculiar geophysical signatures of geological units and faults. Results and conclusions. The new seismic attribute images help to provide solid constraints for the subsurface geological reconstruction of the epicentral area. A high acoustic impedance contrast is visible in the profile NOR1, slightly West of the Norcia basin (Nb) located between 2-3 s TWT (blue arrows, Fig. 2b). A similar signature is clearly detectable also beneath the Castelluccio di Norcia basin (CNb) in line NOR02: this key-horizon, gently dipping toward East, is here deeper, located between 3-4 s TWT (blue arrows, Fig. 3b), and it is abruptly interrupted toward West. According to Porreca et al. (2018), this prominent reflector, which also seems to act as a threshold in depth for the seismicity, may correspond to the Top of the Basement s.l. (sensu Mirabella et al. , 2008). After the attribute analysis, its signature is quite peculiar in term of amplitude of the reflector package, and it is also clearly recognizable in others surrounding lines. Similar characteristics and depth have been also highlighted by Mirabella et al. (2008) in the Colfiorito area, where another significant seismic sequence occurred in 1997-1998. From Fig. 3 - Attribute analysis on NOR2 (Norcia, Nb, and Castelluccio Basin, CNb). a) standard amplitude line; b) Pseudo- Relief displaying the top Basement s.l. (blu arrows) and the main faults pattern (red arrows).