A theoretical comparison among macroseismic scales used in Italy

In a recent work, we evidenced some empirical discrepancies between the macroseismic
intensity estimates in Italy in the last decade with respect to those made previously. A possible
reason might be the progressive adoption by Italian researchers of the European Macroseismic
Scale (EMS) in place of the Mercalli Cancani Sieberg (MCS) scale mostly used
up to 2009. In theory, in modern settlements where reinforced concrete (RC) buildings are
increasingly replacing those in masonry, EMS should overestimate MCS because the former
accounts for the lower vulnerability of RC whereas the latter does not because RC
buildings were not considered at all by the MCS scale since they were almost absent at the
time (1912–1932) when it was compiled by Sieberg. However, such theoretical inference is
contradicted by the empirical evidence that, on average, MCS intensities really estimated
in Italy over the past decade slightly overestimate EMS and not vice versa as it should be.
A possible explanation is that the EMS scale had not been well calibrated to reproduce the
MCS, as its authors intended to do. Another possible reason for the discrepancies between
the last decade and the previous ones might be that the MCS scale applied today is not the
same as that defined by Sieberg at the beginning of the twentieth century. In order to better
understand the possible causes of such discrepancies, we present here a formal comparison
between the definitions of the different degrees of such macroseismic scales. After such
analysis, we might argue that another possible reason for the observed discrepancy may
come from the inaccurate assessment of building vulnerability when assessing the EMS
intensity.

Del Mese S, Graziani L, Meroni F, Pessina V, Tertulliani A (2023) Considerations on using MCS and EMS-
98 macroseismic scales for the intensity assessment of contemporary Italian earthquakes. Bull Earthq
Eng. https:// doi. org/ 10. 1007/ s10518- 023- 01703-0
Ferrari G, Guidoboni E (2000) Seismic scenarios and assessment of intensity: Some criteria for the use of
the MCS scale. Ann Geofisc 43(4):707–720
Galli P, Castenetto S, Peronace E (2012a) May 2012 Emilia earthquakes (MW 6, northern Italy): macroseismic
effects distribution and seismotectonic implications. Alpine Mediterr Quat 25(2):105–123
Galli P, Castenetto S, Peronace E (2012b) The MCS macroseismic survey of the Emilia 2012 earthquakes.
Ann Geophys 55(4):663–672. https:// doi. org/ 10. 4401/ ag- 6163
Gasperini P, Bernardini F, Valensise G, Boschi E (1999) Defining seismogenic sources from historical
earthquake felt reports. Bull Seismol Soc Am 89:94–110
Gasperini P, Vannucci G, Tripone D, Boschi E (2010) The location and sizing of historical earthquakes
using the attenuation of macroseismic intensity with distance. Bull Seismol Soc Am 100:2035–2066.
https:// doi. org/ 10. 1785/ 01200 90330
Graziani L, Bernardini F, Castellano C, Del Mese S, Ercolani E, Rossi A, Tertulliani A, Vecchi M (2015)
The 2012 Emilia (Northern Italy) earthquake sequence: an attempt of historical reading. J Seismol
19:371–387. https:// doi. org/ 10. 1007/ s10950- 014- 9471-y
Grünthal G (ed) (1998) European Macroseismic Scale 1998, Vol. 13, Conseil de l’Europe, Cahiers du Centre
Européen de Géodynamique et de Séismologie, Luxembourg, Luxembourg
Medvedev SV (1977) Seismic intensity scale MSK 76. Publ Inst Geophys Pol Acad Sci A-6(117):95–102
Medvedev SV, Sponheuer W, Karnik V (1967) Seismic intensity scale version MSK 1964. Publ Inst Geodyn
48:Jena
Molin D (2003) Considerazioni sull’eventuale adozione in Italia della scala macrosismica europea (EMS-
1998), GNGTS—Atti del 22° convegno nazionale/06.21, ISBN/ISSN: 88-900385-9-4 (in Italian)
Molin D (2009) Rilievo macrosismico in emergenza, Rapporto interno del Dipartimento della Protezione
Civile, Ufficio Valutazione, prevenzione e mitigazione del rischio sismico (in Italian)
Musson RMW, Grünthal G, Stucchi M (2010) The comparison of macroseismic intensity scales. J Seismol
14:413–428. https:// doi. org/ 10. 1007/ s10950- 009- 9172-0
Rossi A, Tertulliani A, Azzaro R, Graziani L, Rovida A, Maramai A, Pessina V, Hailemikael S, Buffarini
G, Bernardini F et al (2019) The 2016–2017 earthquake sequence in Central Italy: macroseismic survey
and damage scenario through the EMS-98 intensity assessment. Bull Earthq Eng 17:2407–2431.
https:// doi. org/ 10. 1007/ s10518- 019- 00556-w
Rovida A, Locati M, Camassi R, Lolli B, Gasperini P (2020) The Italian earthquake catalogue CPTI15. Bull
Earthq Eng 18:2953–2984. https:// doi. org/ 10. 1007/ s10518- 020- 00818-y
Sieberg A (1912) Über die makroseismische Bestimmung der Erdbebenstärke. Ein Beitrag zur seismologische
Praxis. G Gerlands Beitr Geophys 11(2/4):227–239 (in German)
Sieberg A (1932) Erdebeben. In: Gutenberg B (ed) Handbuch der Geophysik, vol 4, pp 552–554 (in
German)
Tertulliani A, Arcoraci L, Berardi M, Bernardini F, Camassi R, Castellano C, Del Mese S, Ercolani E, Graziani
L, Leschiutta I, Rossi A, Vecchi M (2011) An application of EMS98 in a medium-sized city: the
case of L’Aquila (Central Italy) after the April 6, 2009 Mw 6.3 earthquake. Bull Earthq Eng 7:67–80.
https:// doi. org/ 10. 1007/ s10518- 010- 9188-4
Vannucci G, Tripone D, Gasperini P, Ferrari G, Lolli B (2015) Automated assessment of macroseismic
intensity from written sources using the fuzzy sets. Bull Earthq Eng 13:2769–2803. https:// doi. org/ 10.
1007/ s10518- 015- 9759-5
Vannucci G, Lolli B, Gasperini P (2021) Inhomogeneity of macroseismic intensities in Italy and consequences
for macroseismic magnitude estimation. Seism Res Lett 92:2234–2244. https:// doi. org/ 10.
1785/ 02202 00273