Structural and seismological implications of the 1997 seismic sequence in Umbria and Marche, Italy

A complex sequence of seismic events occurred in September 1997, on the border between Umbria and Marche Regions, in central Italy. The moderate magnitude of the main seismic events resulted in considerable damage to town centres and also to the architectural heritage due to the presence in the area of numerous notable monuments and works of art. In this paper the main characteristics and consequences of the seismic sequence in terms of released energy, magnitude, macroseismic distribution, and the seismic history of the affected area, have been investigated. Next, the strong ground motion derived from the accelerometric records, including significant samples of site effects, was analysed. Finally, as many historical town centres were affected by the seismic shaking, suffering extensive damage and losses of their architectural heritage, a study was carried out on the observed damage to existing constructions.