A study of local site effects in Benevento(Southern Italy) by the analysis of seismic records of explosions

摘要: In this paper we evalllate the seismic amplification effects in town of Benevento llsing records an explo- sion 500 kg fired at abollt 7 km. Seismic were obtained 43 selected sites city by digital three-component stations. A data selection performed on signal-to-noise ratio reduced available to 26 We used spectral techniques evaluate each recording site compared both average spectrum calculated over stations and a reference station. The shapes ratios classified according geological characteristics site. characteristic shape was observed be related specific structure subsoil. particular, basin sediments (Lagonegro Unit) Middle Pleistocene conglomerates failed show effects; thick alluvial deposits showed 5-9 Hz range; finally, alluvial-lacustrine amplified signal frequencies depending thickness deposit. addition, damage distribution caused 1688 earthquake surface layers ancient built-up area town. study ra- tios that these amplify ground motion between 9 12 Hz, i.e. close natural period most widespread buildings time Benevento. Geological jointly carry out zonation urban basis homogeneous responses. validity analysis is limited main frequency band amplitude produced explosions.