SEISMIC CHARACTERIZATION OF THE ACCELEROMETRIC STATIONS ALONG AN ARRAY IN THE SULMONA BASIN Miliana DE CRESCENZO1, Lorenza EVANGELISTA2 Giovanni LANZANO3, Rodolfo PUGLIA4, Anna D’ONOFRIO5, Francesco SILVESTRI6 ABSTRACT The paper summarizes the preliminary results of 1D and 2D seismic site response analyses addressed to the seismic characterization of four accelerometric stations of the RAN (Italian Accelerometric Network) located along an array in the Sulmona alluvial basin, Abruzzo (Italy). The main uncertainties about the morphological and geotechnical soil model of the array concern the morphology and depth of the bedrock and the value of shear wave velocity, VS, at depths greater than 30m. To overcome these difficulties the available geological survey, boreholes, and field geophysical tests, including HVSR and SSR measurements from noise and aftershocks, one cross hole (CH) and two down hole (DH) tests were collected and integrated. The results of the elastic site response analyses at the RAN stations were compared with two recorded events of the Central Italy seismic sequence (24.8.2016 Mw= 6.0 and 30.10.2016 Mw=6.5 earthquakes) in terms of response spectra, amplification factors of peak ground acceleration and spectral intensity. The results revealed that the response towards the middle of the basin is about one-dimensional, while the response at the two stations closer to the border of the valley is significantly affected by the buried morphology of the tectonic contact between the sedimentary soils and the fault rock slope. Keywords: Sulmona basin; central Italy seismic sequence; seismic characterization; 2D numerical analysis 1. INTRODUCTION The Sulmona Basin, also known as Peligna Valley, is one of the easternmost intermountain depression of the Central Apennines. Elongated in the NW-SE direction, it covers an area of about 143 km 2 , and it is characterized by a very steep margin in the eastern part (Morrone Mt., 2061 m a.s.l) in contrast to the flat interior of the basin (Figure 2). Sulmona, located in the heart of this basin, with a population of over 24500 people, relevant industrial activity, and a precious monumental heritage of the Roman and Middle Age, is the most important city of the basin, and, after L'Aquila, is affected by the highest earthquake activity level of the Abruzzo region. This is evidenced by the extensive damages, occurred during historical earthquake (Figure 1). Apart from the event of the 2 nd Century AD, the greatest effects are attributed to the earthquake of November 3, 1706, with epicentre in the Maiella area, valued at 9-10 MCS. The city suffered substantial damage (I 8-9 MCS) also after the historical events of 1349 and of 1456 and the more recent Marsica 1915 and Maiella ,1933 events. (DBMI15-Italian Macroseismic Database 2015). 1Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Naples, Italy, milianadecrescenzo@gmail.com 2Office for Planning, Central Management for the Support to Scientific Network and Infrastructures, National Research Council of Italy, Rome, Italy, lorenza.evangelista@cnr.it 3National institute of geophysics and volcanology, Milan, Italy, giovanni.lanzano@ingv.it 4National institute of geophysics and volcanology, Milan, Italy, rodolfo.puglia@ingv.it 5Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Naples, Italy, anna.donofrio@unina.it 6Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Naples, Italy, francesco.silvestri@unina.it