The 7 and 11 May 1984 earthquakes in Abruzzo-Latium (Central Italy): reappraisal of the existing macroseismic datasets according to the EMS98

The aim of this paper is to provide a complete
and reliable macroseismic knowledge of the events that
stroke a large area in Central Italy on 7 and 11
May 1984. Previous studies, together with original
accounts integrated with new and unpublished information,
have been gathered and examined in order to reevaluate
macroseismic intensities in terms of the
European Macroseismic Scale (EMS98). New intensity
maps have been compiled; the total number of localities
with available information for both the shocks increases
from 1254 of the previous study to 1576. On the basis of
the new dataset, the macroseismic magnitude of the first
shock is MW 5.6 which is lower than the previous
macroseismic computation (MW 5.7). Moreover, the
topic of assessing macroseismic intensity in the presence
of multiple shocks has been also investigated,
proposing an unconventional approach to presenting
the macroseismic data: an overall picture of the cumulative
effects produced by all the seismic sequence is
given to support a partial but faithful reconstruction of
the second shock. This approach is inspired by the
common experience in interpreting historical seismic
sequences and gives a picture of the impact of the
1984 events on the territory.