Macroseismic data in Italy. Early questionnaires and postcards: a brief history and commentary (19th and 20th centuries)

This paper is divided into two parts: the first presents a summary of the history of macroseismic collection data in Italy, from an initial experience in the mid-19th century, to the beginning of the use of macroseismic postcards and their evolution in the first decades of the 20th century; the second part analyses a number of specific aspects of the content of macroseismic postcards. An example of the reading difficulties that these postcards pose is illustrated together with a brief comparison between the Mercalli and Mercalli-Cancani-Sieberg scales, which serve to interpret macroseismic postcards. Both the historical and analytical parts of the paper, aim to improve the comprehension of the sources and, consequently, the knowledge on Italian seismicity.