TITLE:
Possible Multiple Sources of the Strong 1117 Po Plain Earthquake, Inferred from the Plio-Quaternary Evolution of the Northern Adriatic Area
AUTHORS:
Enzo Mantovani, Giuliano Brancolini, Daniele Babbucci, Caterina Tamburelli, Marcello Viti
KEYWORDS:
Northern Adriatic Tectonics, Po Plain, Giudicarie Thrust Zone, January 3, 1117 Earthquake Sources
JOURNAL NAME:
International Journal of Geosciences,
Vol.12 No.4,
April
29,
2021
ABSTRACT: The
strongest documented seismic disaster ever occurred in the Po Plain area
(January 3, 1117, M = 6.5) involved significant damage over a large zone. The
genetic mechanism of such an event, most probably caused by more than one earthquake, is still an object of debate. Above all,
the sources so far proposed cannot account for significant features of the
observed macroseismic field. In this work, we suggest that the damage in the
Verona zone was caused by the activation of a fault in the Lessini tectonic
district, while damage in the central Po Plain may be related to a thrust fault
located beneath the Giudicarie belt. The effects felt in northern Tuscany might
derive from the seismic activation of the presumed SW-ward buried
prolongation of the Giudicarie fault. The presence of such transpressional lithospheric
discontinuity in the Adriatic domain since the upper Miocene and its
reactivation (Pliocene-Pleistocene) as a thrust zone is mainly suggested
by an accurate analysis of the observed deformation pattern in the central
Mediterranean region. The proposed Giudicarie source may also help to explain
the damage observed in the central Po Plain on December 25, 1222, which is not
compatible with the seismic sources so far proposed.