In troubled times, in a divided country: The 1789 Valtiberina earthquake

Abstract

The Valtiberina region (central Italy) has a seismic record going back to the Middle Ages and including five Io>VIII MCS earthquakes, the earliest of which (1352, 1389, 1458), though recently and extensively studied, remain rather poorly known. This makes it all the more important to ensure that the later ones (1789, 1917) are as thoroughly studied as possible. The 1789 earthquake is listed by the current Italian catalogue (CPTI Working Group 2004) with Io VIII-IX MCS and Mm 5.8. These parameters were assessed from a database of twenty-eight macro- seismic intensity data points (Castelli et al. 1996), which is less than plentiful for a late 18th century earthquake. An analysis of the historical context of the 1789 earthquake and its influence on the production of contemporary accounts evidences a few research paths that previous studies either did not or could not take. Fol- lowing them, the macroseismic database of the 1789 earthquake can be noticeably improved, providing the catalogue compiler with a mean to check the reliability of its current parameters.