GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 1.1 85 limite superiore. Considerando che l’ultimo terremoto su questa faglia potrebbe essere avvenuto intorno all’anno 500 e che il tempo di ricorrenza per questa struttura utilizzato per i calcoli di pericolosità sismica è di 1627 anni, l’anticipo effettivo potrebbe essere di poco superiore al secolo. Bibliografia Chiaraluce L. et al.; 2017: The 2016 Central Italy seismic sequence: A first look at the mainshocks, aftershocks and source models . Seismol. Res. Lett., 88, 757-771. Cheloni D. et al.; 2017: Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data . Geophys. Res. Lett., 44, 6778–6787. Mildon Z. K. et al.; 2017: Coulomb stress transfer and fault interaction over millennia on non-planar active normal faults: the M W 6.5-5.0 seismic sequence of 2016-2017, central Italy . Geophys. J. Int., 210, 1206-1218. Tung S. e Masterlark T.; 2018: Delayed poroelastic triggering of the 2016 October Visso earthquake by the August Amatrice earthquake, Italy . Geophys. Res. Lett., 45, 2221-2229. Walters R. J. et al.; 2018: Dual control of fault intersections on stop-start rupture in the 2016 Central Italy seismic sequence . Earth Planet. Sci. Lett., 500, 1-14. Wang R., Lorenzo-Martin F. e Roth, F.; 2006: PSGRN/PSCMP–a new code for calculating co- and post-seismic deformation, geoid and gravity changes based on the viscoelastic-gravitational dislocation theory . Computers and Geosciences, 32, 527-541. A FORESHOCK-MAINSHOCK PAIR, THE 9 JANUARY (MW6.1) - 11 JANUARY (MW7.3) 1693 EARTHQUAKES CASE (SOUTHEASTERN SICILY). PART II: ACTIVE TECTONIC INVESTIGATION AND SEISMOLOGICAL DATA: IMPLICATION FOR SEISMOTECTONIC CONSTRAINTS C. Pirrotta, M.S. Barbano Dipartimento di Scienze Biologiche, Geologiche e Ambientali – Università di Catania, Italy The 9 January (Mw6.1) and 11 January (Mw7.3) 1693 earthquakes occurred in eastern Sicily as a foreshock-mainshock pair. These events triggered numerous environmental effects, described by historical accounts, besides severe damage to houses and infrastructure and numerous fatalities. Environmental effects, such as liquefactions, landslides, fractures and ruptures are mainly clustered in the eastern sector of the Hyblean Plateau. However, historical accounts do not report a clear description of surface faulting in the area of maximum damage. For this reason and given the absence of relevant active faults in the eastern sector of the Hyblean Plateau, various Authors proposed several faults, located nearby, as sources of the 1693 foreshock-mainshock pair. These structures, differing in location, attitude and kinematics are: the NNW-SSE normal to oblique Malta Escarpment Fault System, located in the Ionian offshore; the N-S strike-slip Scicli Ragusa Fault System, the NE-SW normal Avola Fault, the ENE-WSW reverse Monte Lauro Fault, the NNW-dipping Sicilian Basal Thrust and lastly the STEP Faults located in the Ionian offshore (Fig. 1a, see DISS Working Group, 2018 and references therein). The boxer method (Gasperini et al., 1999) application on a revaluation of the 1693 macroseismic fields of the foreshock-mainshock pair (Barbano and Pirrotta, this volume), returns two, partially overlapped, NNE-SSW directed, seismogenic sources. This evidence suggests that the source responsible can be a unique, NNE-SSW oriented, seismogenic fault, located in the eastern sector of the Hyblean Plateau that broke two times during January 9 and January 11, 1693.