GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 mechanical boundary for coseismic rupture propagation processes. Quasi-continuum deformation in the underlying viscous crustal volume generally progressively induces deformation also within the contiguous elasto-brittle rock body. When sufficient elastic energy is stored and critical conditions are reached, a sudden seismic release generally occurs. From the reconstructed 3D model, several 2D transects could be extracted (Fig. 1) allowing to emphasize the presence of different vertically superposed brittle and ductile layers within the investigated volume. As well documented in several other sectors of the broader Aegean Region, seismicity cut-off depth and modelled BDT depth show a good fit (Maggini and Caputo, 2021). Accordingly, we plotted the available hypocentre locations as proposed by different authors (Baker et al., 1997; Louvari et al., 2001; Mu ҫ o et al., 1994) and catalogues (Fig. 1; USGS: purple; CSEM-EMSC: black; GMT: blue; INGV: green) on the rheological sections confirming the general match. Within the investigated area and particularly in correspondence of the analysed seismogenic sources, this boundary occurs between 8 and 18 km. In turn, this double but independent constraint allows to better define the maximum seismogenic depths and hence the down-dip width of the structures. Finally, in order to provide a contribution to the Seismic Hazard Assessment of the broader region, and particularly to realistically delimit the maximum credible magnitude these sources could release, we applied well-known empirical relationships (Wells and Coppersmith, 1994; Leonard, 2014; Thingbaijam et al., 2017) between the surface rupture length or the width versus magnitude. Following this approach, the obtained values of Mw range between 6.7 and 7.3 for the Durresi Offshore Thrust (ALCS315); from 6.7 and 7.2 for the Durresi Backthrust (ALCS325) and from 6.5 to 7.0 for the Vore Backthrust (ALCS335). References Aliaj S., Sulstarova E., Mu ҫ o B. and Kociu S.; 2000: Seismotectonic Map of Albania Scale 1:500.000 . Seismological Institute, Tirana, Albania. Aliaj S., Adams J., Halchuk S., Sulstarova E., Peci V., and Mu ҫ o B.; 2004: Probabilistic seismic hazard maps for Albania . 13th World Conference on Earthquake Engineering, Vancouver, 2469 . Aliaj S.; 2006 : The Albanian orogen: convergence zone between Eurasia and the Adria microplate . Pinter N. et al. (eds.), The Adria Microplate: GPS Geodesy, Tectonics and Hazards, 133-149. Baker C., Hatzfeld D., Lyon-Caen H., Papadimitriou E. and Rigo A., 1997: Earthquake mechanisms of the Adriatic Sea and Western Greece: implications for the oceanic subduction-continental collision transition. Geophys. J. Int., 131 , 559-594. Caporali A., Floris M., Chen X., Nurce B. and Bertocco M.; 2020: The November 2019 seismic sequence in Albania: Geodetic constraints and fault interaction . Remote Sens., 12 (5), 846, DOI 10.3390/rs12050846