GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 concerns the kinematics, based on the overall geodynamic setting of the study area and the mean orientation of the faults, the rake is set in the range 80°-100° for all three sources. The Durresi Offshore Thrust (ALCS315) likely represents the frontal most basal detachment of the accretionary wedge in this sector of the chain. The fault trace (uppermost tip-line) possibly emerges offshore the Albanian coast with a strike varying between 330° and 345° (Aliaj et al., 2000; 2004; Guzman et al., 2011) dipping ENE-wards. From available geological maps and the analysis if the earthquakes distribution, the overall length is around 70 km (Aliaj et al. 2000; 2004; Baker et al., 1997; Guzman et al., 2011; Louvari et al., 2001; Mu ҫ o et al., 1994). The dip angle is inferred from seismic and geological sections (Aliaj, 2006; Roure et al., 2004; Skrami, 2001; Velaj, 2001) and ranges between 20° and 50° with the lower values likely in the deeper sector, progressively steepening upwards. The maximum depth is tentatively assumed around 18 km according to seismicity distribution (Baker et al., 1997; Louvari et al., 2001; Mu ҫ o et al., 2004) and it has been confirmed by our rheological modeling (see following paragraph). Following the above parametres, a width of almost 40 km could be trigonometrically calculated, taking also into account the curved shape in section view. On the other hand, similar values could be indirectly obtained by applying empirical relationships between length, Mw and width. The Durresi Offshore Thrust is also considered by many authors as the causative source for the Mw 6.4 26 November, 2019 Durresi mainshock (e.g. Caporali et al., 2020; Ganas et al., 2020; Papadopoulos et al., 2020; Vittori et al., 2021) on the basis of geodetic data inversions. Figure 1. Investigated area; contour interval at 100 m; CSSs from GreDaSS database (Caputo and Pavlides, 2013); seismicity with Mw > 4.5 from various catalogues (USGS: purple, CSEM-EMSC: black, GMT: blue, INGV: green); focal mechanism solution for the 26 November, 2019 Durres mainshock from USGS catalogue.