Geoscience Reference
In-Depth Information
Rovereto (1955), which actually originated from the far field effects of events oc-
curred in Germany and France, respectively (Camassi et al., 1994). Although the
epicentral intensity was low, Margottini and Screpanti (1991) attributed the mag-
nitude of the “true” earthquakes, respectively Ms 5.87 and Ms 5.26, to the two
presumed “Italian” earthquakes (Camassi et al., 1994). Most of these problems are
now solved; unfortunately it must be admitted that the CPTI04 catalogue (CPTI
Working Group, 2004) still shows the 1991, Graubuenden earthquake as located
in the area of Lecco, due to the fact that - also in this case - only Italian data
were used.
As for the size, the Io of many events, if not most of them, were found to be
overestimated by at least one degree MCS. This was due, in most cases, to the
conservative approach used by the compilers of the previous catalogues, all involved
in safety planning issues.
The event of 1304, 23 October, listed by Postpischl (1985a) as happened in 1303
because of a misinterpretation of Baratta (1901), located near Vicenza, Io 8 MCS,
Mm 5.2, was given Io 7 MCS by ENEL (1985). The earthquakes of 1287 (Cremona),
1334 (Monte Baldo), 1410 (Verona), saw their Io drop from about 8 to less than 6
(ENEL, 1985).
A very interesting case is the event of 7 May 1473, located by Postpischl (1985a)
and previous compilers between Pavia and Lodi, Io 9, Mm 5.2. Further studies
(ENEL, 1985; Gazzini et al., 1991) excluded the possibility that it caused serious
damage, especially in Milano, on the basis of the diary by Cicco Simonetta (15th
cent.), secretary of the Duke of Milano; its maximum intensity was re-evaluated as 5
MCS. This event is interesting because the documents of the Archive of the Sforza
family (1454-1535), although they do not mention damage, report a considerable
interest by the Duke in the event to such an extent that, on May 12th, 5 days after
the event, he wrote to his ambassadors in varied Italian cities, such as Bologna,
Roma and Napoli, asking whether the earthquake had been felt there:
“A dı septe del presente mese circa le tredece hore fo qui nel dominio notro in diversi lochi
uno terremoto el quale duro pocho et non fece nocumento alcuno a li edificii. Desideramo
intendere si lo e intervenuto altrove, pero volimo tu ne scrive et daghe aviso si dicto terre-
moto e stato sentito lı et ne le terre circumstante et quanto dur`oetsilohanociutoalecase
et particularmente de tutto quello che e possuto intervenie per tale casone”. (ASMi, 1473a)
[On the 7th of this month, at about thirteen hours, there was an earthquake in our domain, in
different places, which lasted shortly and did not cause any damage to buildings. We would
like to know whether this event happened in others places, so we would like that you write
about it and give information whether this earthquake was felt there and in the nearby areas,
how long it lasted and whether it damaged houses and all the things that could have happend
for this reason].
He got negative answers from Roma and Napoli (ASMi, 1473b; 1473c), while the
Ambassador in Bologna wrote:
“Rispondo che l'`epiu d'un mese che per alcuni se disse esserci stato alcun movimento sul
fare del dı, ma fu sı breve et sı leve ch'el parse essere in noticia de pochi et come di cosa
quasi non ben certa non se ne fece caso” (ASMi, 1473d)
Search WWH ::
Custom Search