SUMMARY
In this paper we report the results of several investigations aimed at evaluating ground motion scenarios for the September 26th, 1997 Colfiorito earthquake (Mw 6.0, 09:40 UTC). We model the observed variability of ground motions through synthetic scenarios which simulate an earthquake rupture propagating at constant rupture velocity (2.7 km/s) and the inferred directivity. We discuss the variability of kinematic source parameters, such as the nucleation position and the rupture velocity, and how it influences the predicted ground motions and it does not account for the total standard deviation of the empirical predictive model valid for the region. Finally, we used the results from the scenario studies for the Colfiorito earthquake to integrate the probabilistic and deterministic approaches for seismic hazard assessment.