INGV Istituto Nazionale di Geofisica e Vulcanologia
Abstract
The large-scale studies of historical seismology carried out in Italy and Europe in the last decades were mostly aimed at
improving knowledge about earthquakes that were already listed in the extant parametric catalogues, rather than at
identifying earthquakes that were not listed in them.
From 1992 onwards, some of the authors of this study started to look for such “forgotten” earthquakes in different ways (by
systematic surveys of serial historical sources, or by extensive investigation of local records in selected areas). More than 2000
pieces of evidence related to as many earthquakes not listed by any seismological compilations/catalogues were thus identified.
In 2003 all resources were pooled in a common effort, meant to complete the revision of minor “known” earthquakes carried
out by Molin et al. [2008] with a study of the most relevant “unknown” earthquakes identified so far. We present here the
results of the analysis of 227 damaging earthquakes, 155 of which are “unknown” to the seismological tradition. Other 72
events were listed in the Postpischl [1985] catalogue, but not in newer parametric catalogues, no evidence of damage being
available for them at the time: such evidence has now been found and, in 21 cases at least, it allows for a significant re-evaluation
of macroseismic intensity
