GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.3 GNGTS 2024 tme. To evaluate the dependence of Q c on frequency f, we fltered all the traces in bands centered around 1, 2, 3, 4, 5, 6, 8, 10, 12, 14 and 16 Hz of frequency (as suggested by Bianco et al., 2002, for Southern Apennines). The obtained results show the increase of Q c with f at all the considered T L (Fig. 1). This dependence could be described by the general relaton: Q c (f) = Q 0 f α (1) where Q 0 is the Q c at 1 Hz and α is the atenuaton exponent. Our results show that in the High Agri Valley Q 0 ranges between 8 and 57, whereas α ranges between 0.66 and 1.14, indicatng that the region is tectonically and seismically actve, as found in other adjacent areas (Filippucci et al., 2021 and references therein). Compared with other tectonic regions worldwide, in the High Agri valley Q c (f) is very low at all the investgated frequencies (Fig. 2). This evidence could be interpreted as due to the fuid presence in the investgated crust, thus providing a further hint on the possible role of fuids in the seismicity of the area. A complete characterizaton of seismic atenuaton of the studied area will require further investgatons, that is the separaton of scatering and intrinsic contributons in the total atenuaton and a 3D imaging to highlight the possible relaton between spatal atenuaton anomalies and seismicity distributon in the investgated area. Fig. 1 –Q c distributon related to several tme windows, startng from 1.5*Ts and ending at 10, 15, 20, 25 and 30 s.