ANNALI DI GEOFISICA. VOL 43. N. 4. August 2000 Seismic scenarios and assessment of intensity: some criteria for the use of the MCS scale Graziano Fcrrad and EmmlUcla Guidohoni SGA. Srnria Geojisic(I Ambiente. Bolog1la, Italy Abstract The rnacroseismir.: scale used for the classification or the more thall 33100 seismi<: effects of the Catalogue of Strollg Italial/ Earthquakes (CFT13) is Ihe Men.:alli Cancani Sieberg (MCS). As in all scales, the lIse of the MCS scale ill determining the macroseismic intensity of historical earthquakes involves difficulties regarding the classification of descriptions of a quality nature. These descriptions often lack standardisalion as Icvels of infonnalion and Ihe semantic value of (he statemenls. and (here are also various levels of description of (he damage in relation to lhe various economic and building contexlS. As is known. (he intensity scales werecompilcd to classify the effects of earthquakes contemporary to the observers. The scales are therefore classification lOols designed to be applied from direct observations. The general criteria used in assessment of (he in(ensity degrees arc Ihose of a direcl comparison between the descriptive outlincs gained from hislOrici.11 research and the dcscripliollS given by Ihc differel1( degrees of Ihe s(.:alc. While Ihis is true in a general sense. Ihere are a number of cases where the inlerprctalion may vacillate when the contexl ex,lmincd contains no elemel1ls of clarification. in relation to the levels of detail of Ihe rese<lfch or the context. To understand how the many problems connected to Ihe assessment of imensity of seismic scenarios carried out from historical sources have been solved the criteria applied are here described. Key words IIIClcmseiswic - macFOseislllic illlem'ifY - ,HCS scale I. Introduction The Il1llcroseismic sCllle used for Ihe clllssifi- cation of the seismic effects of the Caralogfle Strong !ra/ion Earthquakes (CFTI3) is the Mercalli Cancani Sieberg (MCS) with twelve degrees (Sieberg. (932). pillS the annotations F = felt aod NF =nol felt. As in all scales, the use of the MCS scale in determining the macroseismic intensity of his- torical earlhquakes involves dirlicuhics regard- Mailillg address: Or. Grazi,lnO Fcrrari. SGA. Slfll'i .. Gcolisica ArnbielllC. Via Bellornbra 2412. 40136 Bologna. IWly: e-mail: ferrari@sga-storiagco.il 707 ing the classification of descriptions of a qualily nature. These descriptions often lack standardi- sation as regards levels of information and the semantic value of the statements. and there are also various levels of description of Ihe damage in relation 10 the various economic and building contexts. Table I and II present the English version of the MCS scale published by Sieberg in 1932 (figs. I a-c and 2). The unusual terms used in the translation correspond to the need to leave un- moditied the seismological significance of the described effects from Sieberg. 1932). Sieberg makes reference to «Fachwerkbau)), a type of historical housebuilding characterized by walls with wooden framework filled with mud and straw. stones or bricks (fig. 3ll) once very diffused in Germany. Numerous examples still survive both in small centers and in impor- tant historical centers. This type of hOLlscbuild-