GNGTS 2021 - Atti del 39° Convegno Nazionale

11 GNGTS 2021 S essione 1.1 THE REACTIVATION OF THE FIANDACA AND NIZZETI TECTONIC LIGNMENTS AND THE SEISMIC CRISIS OF 26 DECEMBER 2018 (MONTE ETNA, SICILY) G. De Guidi 1,2 , F. Cannavò 3 , A. Figlioli 1 , S. Giuffrida 1 , D. Russo 1 , F. Carnemolla 1,2 , F. Brighenti 1,2 1 Università di Catania, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Italy 2 CRUST, Centro inteRUniversitario per l’analisi SismoTettonica tridimensionale con applicazioni territoriali, Università di Catania, Italy 3 Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania Osservatorio Etneo, Italy Abstract. We present the analysis of deformation carried by the geodetic monitoring of the tectonic lineaments along the eastern flank of MT Etna, affected by 2018 volcanic unrest. Ac- cording to Bonforte et al ., (2019) and Novellis et al ., (2019) the intrusion of the hydrofracture responsible of the 24 th and 25 th December 2018 eruptive event, reactivated primarily the Fianda- ca fault causing 26 th December 2018 seismic crisis. The Fiandaca tectonic lineament extends for about 5 km in length between the villages of Fleri and Acicatena, is oriented NNW-SSE (Fig.1). It is characterized by low morphological evidence and by a predominantly normal kinematics with a subordinate right lateral component. The Nizzeti fault is part of the Acicatena-Valverde struc- tural system, it shows from the south to the north, a NNW-SSE - NNE-SSW trending and a normal kinematic with a slight right trastensive component. The uprising feeder dyke generated an E-W oriented remote stress field producing a deformation on the eastern and the western flank of Etna volcano. In particular the stress trajectory determines a stress concentration along the main shear discontinuity given rise an earthquake of M w =4.9 and M L =4.8 (Monaco et al ., 2020). The Fig. 1 - Velocity field of south eastern flank of Mt. Etna.