Publication Date:
2024-01-19
Description:
The complex tectonic evolution of the Alps-Apennines transition zone in NW Italy is still a matter of debate. In
this work, we analyze the 2021–2022 seismic sequences around Genoa to understand how convergence between
Africa and Europe is presently accommodated across the Alps-Apennines transition zone. The map-view distribution
of HypoDD-relocated seismic events reveals a NE-SW alignment for the Savignone seismic sequence, and
NNW-SSE alignments for the Borzonasca and Bargagli sequences. The Borzonasca seismic sequence plots in
correspondence of the Villalvernia-Varzi-Ottone Fault, which is often considered as the boundary between the
Alps and the Apennines, whereas no seismicity is documented along the Sestri-Voltaggio Fault. The main-shock
focal solutions are invariably strike-slip, with near-vertical NNW-SSE and NE-SW to ENE-WSW nodal planes. The
evident earthquake alignments in the study area mark active, km-scale fault planes in the upper crust, pointing to
a scenario of distributed strike-slip deformation in the transition zone between the Alps and the Apennines. The
NE-SW faults are inherited structures that underwent major Neogene rotations and are no longer suitably oriented
to accommodate the northward motion of Adria relative to Europe. The Bargagli seismic sequence may
reflect the formation of new NNW-SSE strike-slip faults in the upper crust that are more suitably oriented to
accommodate the present-day stress field, consistent with the seismotectonic framework outlined by recent
works in the nearby regions of the Adria-Europe plate-boundary zone. Our results highlight the important role of
strike-slip faulting in the Adria-Europe plate boundary zone not only in the past, but also during its present-day
evolution.
Description:
Published
Description:
230101
Description:
OST3 Vicino alla faglia
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
