GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 1.1 89 SBWF well matches with the macroseismic area of the 1693 main shocks and the source models proposed by Barbano and Pirrotta (this volume), and with the area were most of the seismogeological effects during this seismic sequence occurred. We analysed instrumental seismicity occurred during 1994-2013 and relocated by Musumeci et al. (2014). Shocks are mainly characterized by strike slip or transtensive mechanisms and a low-to-moderate energy release at depth 10-25 km. Most of the earthquakes are located offshore in the Ionian Sea between Catania and Siracusa on land in the Augusta area and in the eastern sector of the Hyblean Plateau. In addition, seismicity distribution depicts an alignment of earthquakes and two main clusters of seismicity, in the eastern side of the Hyblean Plateau, along a nearly N-S direction (Fig. 3c and d) (Cultrera et al. , 2015; Musumeci et al. , 2015). This band of seismicity overlaps the hypothesized NNE-SSW SBWF. In addition, considering its possible prosecution in the Ionian offshore SBWF holds compatibility with the 11 January shock also as it regards the occurrence of the tsunami. Given the previous discussed evidence we hypothesize that SBWF is a possible candidate for Hyblean Plateau seismicity and in particular for the 1693 seismic sequence. The 9 January foreshock enucleates in the south, near Sortino and strongly damaged the localities along the eastern side of the Hyblean plateau; the 11 January mainshock enucleates northern in the Catania plain or offshore and completely destroyed the previous damaged localities and the villages located north of Catania that were not damaged by the 9 January shock. References Azzaro R. and Barbano M.S.; 2000: Analysis of seismicity of Southeastern Sicily: a proposed tectonic interpretation . Ann. Geofis., 43 , 171-188. Boncio P., Lavecchia G., Pace B.; 2004: Defining a model of 3D seismogenic sources for Seismic Hazard Assessment applications: The case of central Apennines (Italy). Journal of Seismology 8: 407–425, 2004. Catalano S., Romagnoli G., Tortorici G.; 2010: Kinematics and dynamics of the Late Quaternary rift-flank deformation in the Hyblean Plateau (SE Sicily). Tectonophysics 486, 1–14. doi:10.1016/j.tecto.2010.01.013 Cultrera F., Barreca G., Scarfì L., Monaco C.; 2015: Fault reactivation by stress pattern reorganization in the Hyblean foreland domain of SE Sicily (Italy) and seismotectonic implications . Tectonophysics, 661 , 215-228, doi:10.1016/j.tecto.2015.08.043 DISS Working Group; 2018: Database of Individual Seismogenic Sources (DISS), Version 3.2.1: A compilation of potential sources for earthquakes larger than M 5.5 in Italy and surrounding areas . http://diss.rm.ingv.it/diss/ , Istituto Nazionale di Geofisica e Vulcanologia; DOI:10.6092 /INGV.IT -DISS3.2.1. Gasperini P., Bernardini F., Valensise G., Boschi E., 1999. Defining seismogenic sources from historical earthquake felt reports. Bull. Seism. Soc. Am., 89, 94-110. Musumeci C., Scarfì L., Palano M., Patanè D.; 2014: Foreland segmentation along an active convergent margin: new constraints in southeastern Sicily (Italy) from seismic and geodetic observations . Tectonophysics, 630 , 137-149, http://dx.doi.org/10.1016/j.tecto.2014.05.017 ANALYSIS OF SOURCE PARAMETERS FOR BOTH NATURAL AND INDUCED SMALL SEISMICITY IN ITALY P. Roselli, M. Pastori, L. Improta Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy In this study we analyse and discuss some source parameters obtained by Full Moment Tensor (FMT) inversions of small earthquakes with ML comprised between 0.3 and 3.0 occurred in Italy. To perform the FMT inversion we use HybridMT technique (Andersen, 2001; Kwiatek et al. , 2016) supported by a detailed 1D velocity model. This methodology is based on the concept that the first P-pulse area is proportional to the seismic moment. The data-input is obtained from