Geodynamic and seismotectonic model of a long-lived transverse structure: The Schio-Vicenza Fault System (NE Italy)
Authors: Zampieri Dario , Vannoli Paola , Burrato Pierfrancesco 
Published: August 2021

Abstract. We make a thorough review of geological and seismological data on the
long-lived Schio-Vicenza Fault System (SVFS) in northern Italy and present for
it a geodynamic and seismotectonic interpretation. The SVFS is a major and high-angle structure transverse to the mean trend of
the eastern Southern Alps fold-and-thrust belt, and the knowledge of this
structure is deeply rooted in the geological literature and spans more
than a century and a half. The main fault of the SVFS is the Schio-Vicenza
Fault (SVF), which has a significant imprint in the landscape across the
eastern Southern Alps and the Veneto-Friuli foreland. The SVF can be divided
into a northern segment, extending into the chain north of Schio and mapped up
to the Adige Valley, and a southern one, coinciding with the SVF proper. The
latter segment borders to the east the Lessini Mountains, Berici Mountains and Euganei
Hills block, separating this foreland structural high from the Veneto-Friuli
foreland, and continues southeastward beneath the recent sediments of the
plain via the blind Conselve–Pomposa fault. The structures forming the SVFS
have been active with different tectonic phases and different styles of
faulting at least since the Mesozoic, with a long-term dip-slip component of
faulting well defined and, on the contrary, the horizontal component of the
movement not being well constrained. The SVFS interrupts the continuity of the
eastern Southern Alps thrust fronts in the Veneto sector, suggesting that it
played a passive role in controlling the geometry of the active thrust belt
and possibly the current distribution of seismic release. As a whole, apart
from moderate seismicity along the northern segment and few geological
observations along the southern one, there is little evidence to constrain the
recent activity of the SVFS. In this context, the SVFS, and specifically its
SVF strand, has accommodated a different amount of shortening of adjacent
domains of the Adriatic (Dolomites) indenter by internal deformation produced
by lateral variation in strength, related to Permian–Mesozoic tectonic
structures and paleogeographic domains. The review of the historical and instrumental seismicity along the SVFS shows
that it does not appear to have generated large earthquakes during the last
few hundred years. The moderate seismicity points to a dextral strike-slip
activity, which is also corroborated by the field analysis of antithetic
Riedel structures of the fault cropping out along the northern
segment. Conversely, the southern segment shows geological evidence of
sinistral strike-slip activity. The apparently
conflicting geological and seismological data can be reconciled considering the faulting style of the
southern segment as driven by the indentation of the Adriatic plate, while the
opposite style along the northern segment can be explained in a sinistral
opening “zipper” model, where intersecting pairs of simultaneously active
faults with a different sense of shear merge into a single fault system.