GNGTS 2018 - 37° Convegno Nazionale

8 GNGTS 2018 S essione 1.1 Dellong, D., Klingelhoefer, F., Kopp, H., Graindorge, D., Margheriti, L., Moretti, M., et al.; 2018: Crustal structure of the Ionian basin and eastern Sicily margin: Results froma wide-angle seismic survey. Journal of Geophysical Research: Solid Earth, 123, 2090–2114. Govers, R. and Wortel, M. J. R.; 2005: Lithosphere tearing at STEP faults: response to edges of subduction zones. EPSL, 236, 505–523. Gutscher, M.-A., Dominguez, S., Mercier de Lepinay, B., Pinheiro, L., Gallais, F., Babon-neau, N., Cattaneo, A., LeFaou, Y., Barreca, G., Micallef, A. and Rovere, M.; 2016: Tectonic expression of an active slab tear from high-resolution seismic and bathymetric data offshore Sicily (Ionian Sea). Tectonics 35, 1. http://dx.doi . org/10.1002/2015TC003898. Gutscher, M.-A., Kopp, H., Krastel, S., Bohrmann, G., Garlan, T., Zaragosi, S., et al.; 2017: Active tectonics of the Calabrian subduction revealed by new multi-beam bathymetric data and high-resolution seismic profiles in the Ionian Sea (Central Mediterranean). Earth and Planetary Science Letters, 461, 61–72. https://doi.org/10.1016/j. epsl.2016.12.020 Maesano F., Tiberi M.M. and Basili R.; 2016: Deep view of the Subduction-Transform Edge Propagator (STEP) fault in the Calabrian Subduction Zone. Geophysical Research Abstracts Vol. 18, EGU2016-16429, 2016 Mele, G.; 1998: High-frequency wave propagation from mantle earthquakes in the Tyrrhenian Sea: new constraints for the geometry of the South Tyrrhenian subduction zone. Geophys. Res. Lett. 25, 2877–2880. Monna, S. and Dahm, T.; 2009: Three-dimensional P wave attenuation and velocity upper mantle tomography of the southern Apennines–Calabrian Arc subduction zone. J. Geophys. Res. 114, B06304. http://dx.doi . org/10.1029/2008JB005677. Neri, G., Orecchio, B., Totaro, C., Falcone, G. and Presti, D.; 2009: Seismic tomography says that lithospheric subduction beneath south Italy is close to die. Seismological Research Letters 80, 63–70. http://dx.doi.org/10.1785/ gssrl.80.1.63. Polonia, A., Torelli, L., Gasperini, L. and Mussoni, P.; 2012: Active faults and historical earthquakes in the Ionian Sea. Natural Hazards and Earth System Sciences 12, 2311–2328. http://dx.doi.org/10.5194/nhess-12-2311-2012. Polonia, A., Torelli, L., Gasperini, L., Cocchi, L., Muccini, F., Bonatti, E., Hensen, C., Schmidt, M., Romano, S., Artoni, A. and Carlini, M.; 2017: Lower plate serpentinite diapirism in the Calabrian Arc subduction complex. Nature Comms. | 8: 2172 | DOI: 10.1038/s41467-017-02273-x Wortel, M.J.R., and Spakman, W.; 2000: Subduction and slab detachment in the Mediterranean- Carpathian Region. Science 290, 1910–1917. A FORESHOCK-MAINSHOCK PAIR: THE 9 JANUARY (MW6.1) - 11 JANUARY (MW7.3) 1693 EARTHQUAKES CASE (SOUTHEASTERN SICILY). PART I. A REAPPRAISAL OF THE SEISMIC SEQUENCE M.S. Barbano, C. Pirrotta Dipartimento di Scienze Biologiche, Geologiche e Ambientali - Università di Catania, Italy In the past, south-eastern Sicily was affected by strong earthquakes such as the 1169, 1542 and 1693 events, with intensity Io up to XI (MCS) and magnitude Mw up to 7.3 (Rovida et al. , 2016). Our study focuses on the area of maximum damage of the 1693 foreshock-mainshock pair (9 and 11 January, Mw≈6.1 and Mw≈7.3, respectively). During this sequence, numerous secondary effects (liquefaction, landslides, fractures and ruptures), described by historical accounts, caused important landscape modifications in the eastern side of south-eastern Sicily. These effects are poorly considered in the reconstruction of the event seismic sources, which are affected by uncertainties and speculation. The ambiguity of the macroseismic field is mainly due to the vicinity to the sea and to the fact that damage of the main shock arise from the summation of the two shocks. Furthermore, accounts report exhaustive descriptions only for the second event (January 11). Consequently, the seismogenic sources of the 1693 foreshock- mainshock are still poorly constrained and several source models where proposed in literature by the inversion of the macroseimic field, often with significant differences (e.g. Sirovich and