THE SHADOW-ZONE OF LARGE ITALIAN EARTHQUAKES. EARLY JOURNALISTIC SOURCES AND THEIR PERCEPTION OF 17TH-18TH CENTURIES SEISMICITY

From their earliest beginnings in the 16th century, journalists never failed to find earth-quakes interesting. As a result, early journalistic sources offer a huge hoard of original earthquake data, mostly untapped to this day for seismological purposes [Camassi and Castelli, 2003]. In the aftermath of large earthquakes, the journalists of the 17th and 18th centuries tended to react in two ways. Either their interest for seismic news would increase, leading them to hunt for more news of the same kind, or it would focus exclusively on the “big one” to the detriment of lesser contemporary earthquakes. In the first case, it was possible that more earthquakes than usual would be given coverage; but in the second case more earthquakes than usual were likely to be overlooked and shadowed by the larger event. Through a comprehensive cross-check of Italian early journalistic sources, this paper attempts to highlight the “shadow-zones” of some major 17th–18th centuries Italian earthquakes.     

LOOKING FOR “NEW” EARTHQUAKE DATA IN THE 17th-18th CENTURY EUROPEAN “NEWSSELLERS” NETWORK

This study was started in the frame of an assessment of the completeness of parametric earthquake catalogues. Its primary aim was to check whether early journalistic sources can yield “new” earthquake data, i.e. data on previously unknown damaging earthquakes and previously unknown data on such already known events. Another aim was to assess the quality of the resulting information, an important matter given the widespread opinion that early journalistic sources are highly unreliable. A large sample of monographical (pamphlets) and serial (gazettes) early journalistic sources was systematically searched for “new” earthquake data. The results show them to have a high informative content, while being no more unreliable than most historical sources. It is safe to assume that a large-scale combined effort to put this informative potential within general reach would give a great impetus towards increasing the completeness of the parametric earthquake catalogues of most European (and also non-European) countries.