Scuola di Dottorato "Archimede" in Scienze, Comunicazione e Tecnololgie, indirizzo Scienze della Terra, Ciclo XXVII, a.a. 2015-2016The Catanzaro Trough is a Neogene-Quaternary basin developed between the Serre
and the Sila Massif, filled by up to 2000 m of Upper Miocene to Quaternary sedimentary
succession, belonging to the central Calabrian Arc and extended from offshore,
Sant’Eufemia Basin (SE Tyrrhenian Sea), to the onshore, Catanzaro Basin.
By joining on land geo-structural with marine geophysical data, we performed a
detailed analysis of processes that during last 5 My have controlled the evolution of
western portion of the Catanzaro Trough. The fieldwork study, focused on the onshore
area, has allowed to acquire more than 700 fault planes, classified on the base of
kinematics and fault directions, whereas the geophysical data (sub-bottom, multi- and
mono-channel seismic profiles), coming from some scientific cruises within the
Sant’Eufemia Gulf (SE Tyrrhenian Sea), gave us the opportunity to reconstruct the
tectono-stratigraphic evolution of the offshore area.
The combination amongst abrupt sea level changes, transpressional and
trans/extensional tectonics and back-arc Tyrrhenian subsidence during SE-drifting of
Calabrian Arc controlled sedimentary basin hosted by the Catanzaro Trough, as the result
we have recognized three tectonic events formed in the Upper Miocene- Zanclean,
Piacezian-Lower Pleistocene, and Middle-Upper Pleistocene.
The data analysis provide information about stratigraphy and tectonics in the strata
and also give some indication of the tectono-stratigraphic architecture. Sedimentary basin,
in fact, looks to be mainly controlled by the activity of NW–SE and NE–SW oriented fault
systems.
The NW-SE oriented faults showing strike slip and oblique kinematics can be
considered responsible for the opening of a WNW–ESE paleo-strait connecting the
Tyrrhenian Sea with the Ionian Sea during multi-phases tectonics that have acted in the
study area since Miocene. The integrated geo-structural and geophysical data show a
change from left-lateral to right-lateral kinematics during Piacezian-Lower Pleistocene, as
the result of a change of the stress field.
Since Middle Pleistocene, the study area experienced an extensional phase, WNWESE
oriented, controlled mainly by NE-SW and subordinately N-S oriented normal faults,
which split obliquely the western Catanzaro Trough, producing up-faulted and downfaulted
blocks, arranged as graben-type systems, extending from onshore to offshore area. In agreement with and Jacques et al., (2001) and Presti et al., (2013), the NE-SW and NS
trend normal faults play a relevant role as part of recent seismotectonic processes
controlling the Late Quaternary geodynamic of the central Calabrian Arc, representing the
source of the main destructive earthquakes occurred in the area.
Thanks to these multidisciplinary approach we are able to provide a more reliable and
detailed structural frame of the central Calabria segment, providing new elements about recent
activity of faults, and giving a further contribution for the seismogenetic potential assessment
of an area historically considered with the highest earthquake and tsunami risk throughout
Italy.Università della Calabri
