How Historical Seismology Can Benefit from Bureaucracy: The Case of the “Lettere Patenti” in the City of Rome in 1703

Abstract

The 1703Mw 6.9 seismic sequence (I0 11 Mercalli–Cancani–Sieberg scale) was one of the most important crises ever occurred in Italy and has left a deep mark on the seismic history of cities and towns of central Italy. Abundant documents testify the damage suffered by the city of Rome during this sequence; however, the descriptions are mainly referred to monumental buildings. For the recent macroseismic practice, such edifices are not statistically representative when used for assessing macroseismic intensity; instead, the information about residential housing provides reliable data especially when using the European Macroseismic Scale 1998. In this work, we show that useful information regarding the ordinary residential stock can be retrieved in the bureaucratic documentation, apparently distant from the repertoires traditionally used for historical seismology studies. In particular, we used administrative acts granted by the government of Rome to authorize maintenance works on the external parts of the buildings, namely the “Lettere Patenti.” The scrutiny of these sources allowed us to enrich the available dataset introducing 93 new damage points found on civil building stock spread in the historic center of Rome. The new dataset contributes to better define the picture of the effects of the 1703 seismic sequence in Rome, which allowed us to assess macroseismic intensity with more confidence.