GNGTS 2016 - Atti del 35° Convegno Nazionale

92 GNGTS 2016 S essione A matrice Moro, M., Chini M., Saroli M., Atzori S., Stramondo S., Salvi S.; 2011: Analysis of large, seismically induced, gravitational deformations imaged by high-resolution COSMO-SkyMed synthetic aperture radar . Geology, 39(6), 527–530, DOI 10.1130/G31748.1. Valoroso, L., Chiaraluce L., Piccinini D., Di Stefano R., Schaff D., Waldhauser F.; 2013: Radiography of a normal fault system by 64,000 high-precision earthquake locations: The 2009 L’Aquila (central Italy) case study . J. Geophys. Res. Solid Earth, 118, DOI 10.1002/jgrb.50130. Vannoli, P., Burrato, P., Fracassi, U., Valensise, G.; 2012; A fresh look at the seismotectonics of the Abruzzi (Central Apennines) following the 6 April 2009 L’Aquila earthquake (Mw 6.3) . Ital. J. Geosci., 131, 309-329, DOI 10.3301/ IJG.2012.03. EVIDENCES FROM THE PRELIMINARY MACROSEISMIC SURVEY OF THE AUGUST 24, 2016 AMATRICE SEISMIC SEQUENCE (CENTRAL ITALY) M.A. Zanini, L. Hofer, F. Faleschini, P. Zampieri, N. Fabris, C. Pellegrino Dipartimento di Ingegneria Civile, Edile e Ambientale, Universita’ degli Studi di Padova, Italy Introduction. On August 24, 2016, at 3:36 local time (1:36 UTC) a Mw 6.0 earthquake occurred in Central Italy, at the boundaries of Lazio, Abruzzo, Marche and Umbria regions. The Italian Strong Motion Network of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) located the epicentre at 42.70 ° N and 13.24 ° E, between the Municipalities of Accumoli and Amatrice, in the Lazio region (ISIDe, 2016). The area hit by the seismic event is highly prone to seismic hazard and in the past twenty years two important earthquakes occurred. In 1997 a M w 5.97 earthquake hit the Umbria region, while in 2009 L ’ Aquila Earthquake caused about 300 victims. Historically, the Parametric Catalogue of Italian Earthquakes (CPTI15) (Rovida et al., 2016) shows the high seismic activity of the examined zone in which from the eighteen century a mean annual rate of about 0.25 events with M w greater than 4.0 was observed. First memories of the seismic activity in the area of Accumuli, date back to the M w 5.3 Monti della Laga event, which occurred on July 1627 and related to a I 0 7-8 MCS macroseismic level of damage (Monachesi and Castelli, 1992). On October 7, 1639, a Mw 6.21 (I 0 8-9 MCS) earthquake hit Amatrice and its fractions (Castelli, 2013). The strongest event occurred in 1703 (January 14; I 0 10 MCS, M w 6.92), ca. 20 km from the 2016 epicenter and subsequently in 1730 the area was re-struck by a M w 6.04 earthquake (May 12, I 0 7 MCS) (Guidoboni et al., 2007). After about 150 years, on November 7, 1883, these territories were hit again by the Monti della Laga earthquake (I 0 7 MCS, M w 5.1) and finally in the twentieth century other three significant events occurred (1916, 1950 and 1979) (Tertulliani et al., 2006). Survey methodology. After the 2016Amatrice seismic sequence, teams of the University of Padova performed a field survey of the entire area involved by the earthquake, aiming to develop the macroseismic damage scenario of the event. The Macroseismic-Intensity assessment was performed according to the European Macroseismic Scale (EMS 98) (Gr ü nthal, 1998) and the survey was continuously updated until September 6, 2016 to consider the effects of the cumulative damage caused by the occurred aftershocks. The teams performed detailed survey of 180 localities, assessing the intensity level on the basis of the structural damage observed and the vulnerability class of the buildings. These localities are distributed within the Provinces of Rieti (Lazio), Aquila and Teramo (Abruzzo), Perugia (Umbria) and Ascoli Piceno, Fermo and Macerata (Marche). In addition, short interviews on the earthquake perception were performed to better characterize especially the lowest grades of damage and macroseismic intensity levels. Most of the structures in the surveyed area, are one-or-two-story old stone-masonry residential buildings, with low quality mortar joints and with lack of connections (vulnerability class A and B).