Journalistic communication in the 17th-18th centuries and its influence on the completeness of parametric catalogues

Current European parametric catalogues are still based, to a large extent, on the �seismological tradition� represented by the historical earthquake compilations issued between the second half of the 19th century and the first decades of the 20th century. Relatively few earthquakes from outside this tradition are included in the existent parametric catalogues, and those mostly as the result of fortuitous findings. No large scale search of such events has ever been carried out, mainly because of a widespread � if not expressed in such terms � consensus that such operations would be too costly and yield little. Being unlikely that strong earthquakes have been overlooked by any sort of compilation, these investigations would only yield low earthquakes, not effective for the definition of seismic hazard. The authors of this paper believe that a systematic inspection of journalistic sources from the 17th and 18th centuries can significantly contribute towards improving the knowledge of the seismicity of the past, both in general (by leading to the discovery of previously unlisted earthquakes) and also with reference to the retrieval of information on previously unknown earthquakes capable of significant damage, and therefore important for hazard evaluation purposes.