Interactions between volcanism and tctonics in the western Aeolian sector, southern Tyrrhenian Sea

New high-resolution bathymetric and magnetic data from the western Aeolian sector, southern
Tyrrhenian Sea, provide insights into structural and volcanic development of the area, suggesting
a strong interaction between volcanism and tectonics. The analysis of these data combined
with relocated earthquake distribution, focal plane solutions and strain rate evaluation indicates
that the dextral strike-slip Sisifo-Alicudi shear zone is a complex and wide area of active
deformation, representing the superficial expression of the deep seated lithospheric tear fault
separating the subduction slab below Sicily and Calabria. Most of the observed volcanic features
are aligned along a NW–SE trend, such as the Filicudi island-Alicudi North Seamount
and Eolo-Enarete alignments, and are dissected by hundred-metre-high scarps along conjugate
NNE–SSW trending fault systems. The magnetic field pattern matches the main trends of
volcanic features. Spectral analysis and Euler deconvolution of magnetic anomalies show the
existence of both deep and shallow sources. High-amplitude, high-frequency anomalies due
to shallow sources are dominant close to the volcanic edifices of Alicudi and Filicudi, while
the main contribution on the surrounding Eolo, Enarete, Alicudi North and Filicudi North
seamounts is given by low-amplitude anomalies and/or deeper magnetic sources. This is probably
related to different ages of the volcanic rocks, although hydrothermal processes may have
played an important role in blanketing magnetic anomalies, in particular at Enarete and Eolo
seamounts. Relative chronology of the eruptive centres and the inferred deformation pattern
outline the Quaternary evolution of the western Aeolian Arc: Sisifo, Alicudi North and Filicudi
North seamounts might have developed in an early stage, following the Late Pliocene–Early
Pleistocene SE-ward migration of arc-related volcanism due to the Ionian subduction hinge
retreat; Eolo, Enarete and Filicudi represent later manifestations that led volcanoes to develop
duringMid-Late Pleistocene, when the stress regime in the area changed, due to the SSE-ward
propagation of the subduction slab tear fault and the consequent reorientation and decrease
of trench migration velocity. Finally, volcanic activity occurred in a very short time span at
Alicudi, where an almost conical volcanic edifice emerged, suggesting negligible interactions
with regional fault systems.