The Curious Case of the 1346 Earthquake Recorded Only by Very Young Chroniclers

Abstract

The earthquakes of May–June 2012 affected a heavily populated stretch of country on the northeastern border of the Italian administrative region of Emilia Romagna, which is an area of industrial districts that account for up to 2% of Italy’s gross domestic product and the seismicity of which had been, up till then, considered comparatively moderate. Understandably enough, the 2012 earthquakes had great resonance in the media and effect on public opinion. At the present time the Po Valley earthquakes of May–June 2012 are acknowledged as the strongest ones in the known seismic history of the area. For some years before, a major candidate for this distinction was the earthquake of 22 February 1346. An authoritative study (Boschi et al., 1997) credited the 1346 event with a 6.7 magnitude value that earmarked it as potentially one of the strongest historical earthquakes of Northern Italy. Later on, successive revisions of this study (Boschi et al., 2000; Guidoboni et al., 2007) did noticeably alter the epicentral location and estimated energy of the 1346 earthquake, but without explaining why these alterations had become necessary. In the wake of the May–June 2012 earthquakes the seismic history of the area became an object of great interest for historical seismologists. In this context the historical data set collected by previous studies on the 1346 earthquake was subjected to a thorough review and new information was sought. This paper presents the results of the investigation, which suggests the strong possibility that the 22 February 1346 earthquake never did happen at all.