Multidisciplinary study of the Tindari Fault (Sicily, Italy) separating ongoing contractional and extensional compartments along the active Africa–Eurasia convergent boundary
The Africa–Eurasia convergence in Sicily and southern Calabria is currently expressed by two different tectonic
and geodynamic domains: thewestern region, governed by a roughlyN–S compression generated by a continental
collision; the eastern one, controlled by a NW–SE extension related to the south-east-directed expansion of
the Calabro–Peloritan Arc. The different deformation pattern of these two domains is accommodated by a
right-lateral shear zone (Aeolian–Tindari–Letojanni fault system) which, from the Ionian Sea, north of Mt.
Etna, extends across the Peloritani chain to the Aeolian Islands.
In this work, we study the evidence of active tectonics characterizing this shear zone, through the analysis of
seismic and geodetic data acquired by the INGV networks in the last 15 years. The study is completed by
structural and morphological surveys carried out between Capo Tindari and the watershed of the chain.
The results allowed defining a clear structural picture depicting the tectonic interferences between the two
different geodynamic domains. The results indicate that, besides the regional ~N130°E horizontal extensional
stress field, another one, NE–SW-oriented, is active in the investigated area. Both tension axes are mutually
independent and have been active up to the present at different times. The coexistence of these different
active horizontal extensions is the result of complex interactions between several induced stresses: 1) the
regional extension (NW–SE) related to the slab rollback and back-arc extension; 2) the strong uplift of the
chain; 3) the accommodation between compressional and extensional tectonic regimes along the Aeolian–
Tindari–Letojanni faults, through a SSE–NNW right-lateral transtensional displacement. In these conditions,
the greater and recurring uplift activity is not able to induce a radial extensional dynamics, but, under the
“directing” action of the shear system, it can only act on the regional extension (NW–SE) and produce the
second system of extension (NE–SW)