GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 1.1 187 observed at the end of the seismic sequence was supplied, assigning the intensity degree for all localities. Our approach is inspired by the common experience in interpreting historical seismic sequences. In fact in these cases the only available info are usually global descriptions of the observed effects from which it is not possible to distinguish those caused by each shock. This approach, although cannot allow to deduce any information on source parameters (magnitude, location, fault dimention), can be useful to compare historical events occurred in the same area. However, due to the relevance and the frequency of cases encountered in literature, we strongly suggest that the issue of seismic sequences intensity assessment should be faced within the seismological community, in order to reach a shared answer to this matter. References Grunthal G., (Ed.) (1998). European Macroseismic Scale 1998 (EMS-98) . European Seismological Commission, Subcommission on Engineering Seismology, Working Group Macroseismic Scales. Conseil de l�������� ������� ’Europe, Cahiers du Centre Europ��� �� ������������ �� �� ������������ ��� ����������� �� ��� é �� �� en de Géodynamique et de Séismologie, 15, Luxembourg, 99 pp. Guidoboni E., Ferrari G., Mariotti D., Comastri A., Tarabusi G. and Valensise G., (2007), CFTI4Med, Catalogue of Strong Earthquakes in Italy (461 B.C.-1997) and Mediterranean Area (760 B.C.-1500). INGV-SGA. http:// storing.ingv.it/cfti4med/ MouyiannouA., PennaA., Rota M., Graziotti F., Magenes G. (2014), Implications of cumulated seismic damage on the seismic performance of unreinforced masonry buildings, Bull. New Zealand Society of Earthquake Engineering, Vol. 47, N. 2, pp. 157-170, 2014 Rovida A., Locati M., Camassi R., Lolli B., Gasperini P. (eds), 2016. CPTI15, the 2015 version of the Parametric Catalogue of Italian Earthquakes. Istituto Nazionale di Geofisica e Vulcanologia. doi :http://doi.org/10.6092/ INGV.IT -CPTI15. LATE QUATERNARY DEFORMATION IN THE CATANIA URBAN AREA (EASTERN SICILY): RELATION WITH THE ACTIVE TECTONICS G. Tortorici, F. Pavano, G. Romagnoli, S. Catalano Dipartimento di Scienze Biologiche, Geologiche e Ambientali – Sezione di Scienze della Terra, Università di Catania, Italy Introduction. The Catania region is located on the frontal zone of the Sicily collision belt (Fig. 1), along the active Nubia-Eurasia convergent plate boundary. The area is affected by an active NNW-SSE oriented compression that is evidenced by focal mechanisms (Scarfì et al. , 2013), stress in situ measurements (Bousquet et al. , 1988) and geodetic data (De Guidi et al. , 2015). Impressive contractional structures (Monaco et al. , 2002, Catalano et al. , 2004) affect the Middle Pleistocene marine succession which crops out to the southeast of the town (Fig. 1). A short segment of a N80 trending thrust ramp, which brings Middle Pleistocene sands on 80 ka old alluvial conglomerates, crops out in the southern part of the town (Fig. 2). Moreover, in the Catania alluvial plain, to the southeast of the town, a set of ENE-WSW oriented folds (Fig. 1) caused responses of the river channel morphology of the Simeto River (Catalano et al. , 2011). Even if in the urban area of Catania the etnean volcanic cover and the intensive urbanization make it difficult, the recognition of the prolongation of the Late Quaternary contractional tectonics beneath the town is a primary target for assessing the seismic hazard of this densely populated area. In this paper we present new geological data, in order to contribute to a more precise location of the recent contractional features in the substratum of the urban area. Geological evidence of contractional features in the Catania substratum. The Late Quaternary tectonic features of the Catania area modified a very complex geometry, due to the high tectonic mobility of the area. The geology of Catania is characterized by a sedimentary