GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 1.1 37 Palano M., Cannavò F., Ferranti L., Mattia M. and Mazzella E.; 2011: Strain and stress fields in the Southern Apennines (Italy) constrained by geodetic, seismological and borehole data . Geophys. J. Int., 187 (3), 1270–1282. Palano M., Puglisi G. and Gresta S.; 2008: Ground deformation patterns at Mt. Etna from 1993 to 2000 from joint use of InSAR and GPS techniques . Journal of Volcanology and Geothermal Research, 169 , 99-120, doi:10.1016/ j.jvolgeores.2007.08.014. Palano M., Rossi M., Cannavò C., Bruno V., Aloisi M., Pellegrino D., Pulvirenti M., Siligato G., and Mattia M.; 2010: Etn@ref, a geodetic reference frame for Mt. Etna GPS networks . ������ �� ����������� Annals of Geophysics, 53 (4), 48-79, doi:10.4401/af-4879. Rasà R., Azzaro R. and Leonardi O.; 1996: Aseismic creep on faults and flank instability at Mt. Etna volcano . In: McGuire, W.J., Jones, A.P., Neuberg, J. (Eds.), Volcano instability on the Earth and other planets. Geological Society, London, Special Publications, 110 , 179-192, doi: 10.1144/GSL.SP.1996.110.01.14. Rust D. and Neri M.; 1996: The boundaries of large-scale collapse on the flanks of Mount Etna, Sicily . In: McGuire, W.J., Jones, A.P., Neuberg, J. (Eds.), Volcano instability on the Earth and other planets. Geological Society, London, Special Publications, 110 , 193-208, doi:10.1144/GSL.SP.1996.110.01.15 Saastamoinen J.; 1972: Contribution to the theory of atmospheric refraction . Bulletin Géodésique 105 (1), 279-298, doi:10.1007/BF02521844. Savage J. C. and Simpson R. W.; 1997: Surface strain accumulation and the seismic moment tensor. Bulletin of the Seismological Society of America, 87 , 1345-1353. Scarfì, L., Langer, H. and Scaltrito, A.; 2009: Seismicity, seismotectonics and crustal velocity structure of the Messina Strait (Italy) . Phys. Earth Planet. Inter. 177 , 65–78. http://dx.doi.org/10.1016/j.pepi.2009.07.010. Zhang H., Thurber C. and Bedrosian P.; 2009: Joint inversion for Vp, Vs, and Vp/Vs at SAFOD, Parkfield, California . Geochemistry Geophysics Geosystems, 10 , Q110032, doi:10.1029/2009GC002709. Holocene earthquakes along the San Demetrio ne’ Vestini fault (AQ A.M. Blumetti, P. Di Manna, E. Vittori, V. Comerci, L. Guerrieri ISPRA, Geological Survey of Italy, Roma, Italy Introduction and geological framework. In the months following the April 6, 2009, Mw 6.3 L’Aquila earthquake in central Apennines (Italy), the Geological Survey of Italy (ISPRA), through a detailed geological, geomorphological and geophysical surveys, carried out a seismic microzonation of the San Demetrio ne’ Vestini, a territory which experienced damage of 6-7 MCS degree (Galli et al. , 2009). This village lays within the L’Aquila intermountain basin, which is made by a system of northwest-southeast-trending tectonic depressions (total length about 30 kilometers) developed inside the inner sector of the Meso-Cenozoic orogenic belt of the Apennines, between the Gran Sasso and the Monti d’Ocre morphotectonic units (Fig. 1). Active crustal extension across this portion of the Central Apennines is demonstrated by GPS velocities around 3 mm/yr (D’Agostino et al. , 2011), and confirmed by the historical seismicity of the region. There is also wide geological evidence of active faulting (Bagnaia et al. , 1992; Blumetti, 1995; Boncio et al. , 2004; Galadini and Galli, 2000; Roberts and Michetti, 2004; Blumetti and Guerrieri, 2007; Galli et al. , 2010, 2011; Giaccio et al. , 2012; Blumetti et al. , 2013). San Demetrio is located at the southern tip of the L’Aquila basin fault zone, an area characte- rized by en echelon and sub-parallel NW-SE trending fault segments. ���� ���������� ������� �� This structural setting is typical at the transition between two primary fault zones (in this case between the L’Aquila Basin F.Z. and the Subequano Basin fault zone). The territory of the San Demetrio municipality is crossed by four NW-SE trending fault segments that have displaced Quaternary deposits (Fig. 1B; Bosi and Bertini, 1993; Giaccio et al. , 2012). ��� �� ����� ������� ������ ��� ���������� ������� ��� ������� ��� �� ������� �� ��� One of them, cutting across the historical centre, was pointed out as capable by the Working Group MS–AQ (2010). The fault (named San Demetrio fault), identified as a possibly active fault by Bagnaia et al. (1992), does not crop out directly with an evident free-face, but