GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 1.1 55 issues and fault rupture models. Federica Riguzzi provided us with the coseismic GPS offsets of the 18 January 2017 seismic events. We thank all the agencies and institutions that have made the GPS observations available for this study. We thank the European Space Agency for providing Sentinel-1 SAR images (freely available at https://scihub. copernicus.eu/dhus/#/ home). GPS station TER 2 was installed by ISPRA (Istituto Superiore per la Protezione e la Ricerca Ambientale) and we acknowledge Dr Piera Gambino and Dr Stefano Calcaterra for providing us the related GPS data. This research has been partly founded by INGV-FISR Project 2016 Centro di Studio e Monitoraggio dei Rischi Naturali dell’Italia Centrale. References Castellarin A., Colacicchi R. and Praturlon A.; 1978: Fasi distensive, trascorrenze e sovrascorrimenti lungo la ’linea Ancona-Anzio’, dal Lias medio al Pliocene. Geologica Romana, 17 , 161–189. Cheloni D., Giuliani R., D’Anastasio E., Atzori S., Walters R. J., Bonci L., et al.; 2014: Coseismic and post-seismic slip of the 2009 L’Aquila (central Italy) Mw 6.3 earthquake and implications for seismic potential along the Campotosto fault from joint inversion of high-precision levelling, InSAR and GPS data. Tectonophysics, 622 , 168–185. https://doi.org/10.1016/j.tecto.2014.03.009. Chiaraluce L., Di Stefano R., Tinti E., Scognamiglio L., Michele M., Casarotti E., et al.; 2017: The 2016 central Italy seismic sequence: A first look at the mainshocks, aftershocks and source models. Seismological Research Letters, 88 (3), 1–15. https://doi.org/10.1785/0220160221. Galadini F. and Galli, P.; 2003: Paleoseismology of silent faults in the central Apennines (Italy): The Mt. Vettore and Laga Mts. faults. Annals of Geophysics, 46 (5), 815–836. Galadini F. and Messina, P.; 2001: Plio-Quaternary changes of the normal fault architecture in the central Apennines (Italy). Geodinamica Acta, 14 , 321–344. Galli P., Galadini F. and Pantosti D.; 2008: Twenty years of paleoseismology in Italy. Earth Sciences Review, 88 , 89-117. Lyakhovsky V., Ben-Zion Y., Ilchev A. and Mendecki, A.; 2016: Dynamic rupture in a damage-breakage rheology model. Geophysical Journal International, 206 , 1126–1134. Tavarnelli E., Butler R.W.H., Decandia E.A., Calamita F., Grasso M., Alvarez W. and Renda P.; 2004: Implications of fault reactivation and structural inheritance in the Cenozoic tectonic evolution of Italy. In U. Crescenti, S. D’Offizi, S. Merlini, & R. Sacchi (Eds.), The nature and tectonic significance of fault zone weakening, Special Publications (Vol. 186, pp. 273–286). London: Geological Society. Tinti E., Scognamiglio L., Michelini A. and Cocco M.; 2016: Slip heterogeneity and directivity of the ML 6.0, 2016, Amatrice earthquake estimated with rapid finite-fault inversion. Geophysical Research Letters, 43 , 10,745– 10,752. https://doi.org/10.1002/2016GL071263. Valoroso L., Chiaraluce L., Piccinini D., Di Stefano R., Schaff D. and Waldhauser F.; 2013: Radiography of a normal fault system by 64,000 high-precision earthquake locations: The 2009 L’Aquila (central Italy) case study. Journal of Geophysical Research: Solid Earth, 118 , 1–21. https://doi.org/10.1002/jgrb.50130 Wells D.L. and Coppersmith K.J.; 1994: New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bulletin of the Seismological Society of America, 84 , 974–1002. THE DAMAGING SEISMIC EVENT OF AUGUST 21, 2017 ON ISCHIA ISLAND (SOUTHERN ITALY): CONSTRAINTS ON THE SOURCE MECHANISM D. Famiani 1 , S. Cesca 2 , T. Braun 1 1 Istituto Nazionale di Geofisica e Vulcanologia, Italy 2 GFZ German Research Center for Geosciences, Potsdam, Germany Introduction. On August 21, 2017, Ischia was struck by a seismic event of M D 4.0 that provoked significant shaking and severe damages (maximum intensity reached in Casamicciola village;Azzaro et al. , 2017) including 2 victims. The incongruity between damage andmagnitude cannot be explained only by local site effects or especially vulnerable constructions, but may be influenced by particular characteristics of the seismic source. The first automatic hypocenter location at INGV was off-shore at a standard crustal depth of 10 km in the area between Ischia island and the Italian Peninsula. Relocation of the event confirmed a shallow hypocenter