Evaluation of site effects after the 2009 Abruzzo Earthquake using numerical and experimental analyses for the reconstruction planning

The earthquake of April 6th, 2009 in L’Aquila area is one of the largest seismic events of the last years in Italy. The events, that caused significant damage in a large area of Abruzzo regions (cental Italy) and site amplification phenomena, were recorded even at large distances from the epicentre. After the emergency period, a detailed study of the surface effects was necessary for the post-earthquake reconstruction, but in a way it should be carried out rapidly enough to give instructions to urban planners, codes to public administrators and information to engineers. A team of surveyors were trained to collect field information such as geologic and geomorphologic features and geotechnical or geophysical information. The expected seismic inputs were provided, and the collected information where analyzed with the aid of dynamic codes to calculate the possible local site effects. The results are presented as response spectra and amplification coefficients. In this paper the results for one of the most severely damaged area (up to IX-X MCS), the Paganica – Tempera – Onna - San Gregorio area, located 6 to 10 km east of the April 6th main shock, are presented.