Encoding and computer analysis of macroseismic effects

Abstract

We propose a method for the encoding and the computer analysis of the macroseismic effects deduced from historical sources allowing the complete formalization of the process of seismic intensity assessment. In the framework of historical sismology we make use of a multi-criteria decisions-support algorithm, based on the theory of the Fuzzy Sets. By analyzing the texts of the available sources for the 1919 Mugello and 1920 Garfagnana earthquakes, we followed a classification criterion which is independent of any macroseismic scale: we “disarrange” each sentence reported on the sources into 5 syntactic elementary components and represent it by a set of alphanumeric codes. This allows us to retain the maximum adherence to the original sources and to avoid forced interpretations and losses of information due to the need of fitting a given description to each observed effect. Moreover this scheme also allows to gather equivalent effects by reassigning them the same code, and to use this new classification in further processing. This procedure could even be seen as an attempt to define a new macroseismic scale on the basis of a statistical counting of different effects occurrences.