GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 the seismological tradition were recovered and critically analyzed, and only later was specific bibliographic and archival research carried out to identify new sources, which allowed the available information to be integrated. It is important to bear in mind that the political, economic, social, and cultural circumstances that characterize each historical period strongly influence the characteristics, completeness, and availability of the types of sources. Consequently, despite the small size of the chronological window considered, both the documentation produced and its analysis and interpretation were conditioned by evident limitations of the available sources. Starting from the reference studies of the CPTI15 catalogue, the most important seismic repertories and catalogues were first consulted, such as that of Iaccarino and Molin (1978), or the later PFG catalogue (Postpischl, 1985), in which the six earthquakes are listed. The main seismological compilations, both of national interest as well as those specific to north-eastern Italy, many of which were fruitless as they were not very thorough, such as Goiran (1886, 1892), Piovene (1888), Scarpa (1888), Taramelli (1888) and Zanon (1937). Among these, however, a relatively in-depth work, which therefore deserves special mention, is that of Spagnolo (1907) who reports on the events of 1887, 1897, and 1900. In many cases, these compilations, whose information is derived from scientific observations, direct and indirect testimony, contemporary newspaper reports, and manuscript works, represent the main source of qualitatively important information on the effects of the tremors in individual localities. In the specific case of the six earthquakes considered here, the original macroseismic ‘postcards’ were recovered: questionnaires sent to municipalities to collect information on macroseismic effects, available only for the earthquakes of 14 April 1887 (Marostica), 11 June 1897 (Asolano) and 4 March 1900 (Trevigiano). The majority of these documents are macroseismic postcards in the strict sense, while a small part is made up of correspondence or telegrams, and in some cases, they are also enriched by short descriptive reports, newspaper cuttings, etc. It is important to emphasize that sometimes this documentation may be of little use in assigning an intensity value; in several cases in fact, the observer or speaker has merely assigned an intensity value without providing further descriptive elements that would allow them to be integrated with other sources, further complicating the interpretation process. Among the main sources of information for the study of earthquakes, national, and especially local newspapers (when available and accessible) are of particular interest. Although newspapers are strongly influenced by the socio-political, economic, and cultural situation of the historical period in which they are produced; their contribution proved to be of fundamental importance, in most of the earthquakes examined, for reconstructing the picture of macroseismic effects. On the other hand, the earthquakes of May 1861 and July 1919 are significant: the systematic review of journalistic sources for these two events was unsuccessful, probably due to the particular historical contingencies, the Unification of Italy, and the first post-war period, respectively. Finally, a source that is certainly not marginal is the information obtained through seismological bulletins, which constitute the main background to the compilation of the PFG catalogue and are