Valutazione della pericolosità sismica in alta Valtiberina

This study describes the assessment of probabilistic seismic hazard in Alta Valtiberina performed in the framework of a project funded by Regione dell'Umbria. Starting from the evaluation of the seismogenic potential, the analysis has been done first on the site of Città di Castello to determine the input ground motion, hence the same procedure was applied to the other test sites of the study area. The procedure adopted includes the evaluation of (5% damped) acceleration pseudo response spectra PSA and peak of acceleration PGA, corresponding to the 90% probability of being non-exceeded in 50 years (475 years return period). Finally, and only for the site of Città di Castello, input ground motion was determined using a stochastic finite fault technique based on geological and historical information available for the 1789 earthquake.