A long seismic sequence affecting the Umbria-Marche region (Central Italy) started on September 26, 1997. Earthquakes with intensities up to IX MCS caused diffused damage over a large area. The resulting damage pattern is investigated, for villages settled in an intermountain basin near the epicentral area. Macroseismic data are collected and compared with the surface geology for 15 villages and hamlets within a restricted area. Among these 15 settlements, six individual groups are discernable showing a gradual variation of the damage severity. Such abrupt damage variation inside a relatively small area is influenced by modest scale lithological transitions. In particular, major effects occurred in those villages settled in the sedimentary basin close to border faults. Safest sites resulted to be those settled on bedrock and on the alluvial plane far from the edge. These observations support models existing in literature, which claim that edge effects and the generation of diffracted waves in soft basins can contribute to a stronger shaking. ¿ 1999 American Geophysical Union