Comment on “The Curious Case of the 1346 Earthquake Recorded Only by Very Young Chroniclers” by Romano Camassi and Viviana Castelli

The article by Camassi and Castelli (2013) (hereinafter CC13) deals with the 1346, northern Italy earthquake, one of hundreds of medieval earthquakes that were investigated in Italy from 1983 to 2007. Regrettably, the article does not add any new data but only proposes a revision and a reinterpretation of published materials. CC13 first criticized the variability of magnitude estimates assigned to this earthquake in catalogs published in Italy over the past 20 years, then went so far as to question whether the 1346 earthquake actually occurred. Their analysis, however, is fraught with demonstrable mistakes in the analysis of medieval texts, such that their conclusions are objectionable both from the point of view of historical criticism and from that of historical seismology. Such conclusions may critically affect the assessment of seismic hazard in a heavily populated and industrialized portion of the Po Plain (northern Italy), right at a time when the threat posed by strong earthquakes in this region is being rediscovered by the citizens and by their administrators following the 20 and 29 May 2012, Emilia events (Mw 6.0 and 5.9). As the coauthors of the catalogs being questioned, we feel an obligation to re-establish what is the evidence supporting 1346 being a real major earthquake and why its magnitude is still uncertain.