Design earthquake from site-oriented macroseismic hazard estimates

A procedure is presented to determine design earthquakes that are compatible with seismic hazard estimates deduced in terms of macroseismic intensity from a distribution-free, site-oriented approach. Through this procedure it is possible to identify past earthquakes that were mostly responsible for the local hazard, as well as to identify representative magnitude distance pairs to be used for engineering purposes. An example applied to central Italy is discussed and reveals that a design earthquake provided by the approach described here is significantly different from that provided for the same site by the standard disaggregation analysis. This discrepancy is the effect of a different use of information available for hazard assessment at the site under study.