The general basin and range Apennine topographic
characteristic is generally attributed to the presently active normal fault
systems, whose long-term activity (throughout the Quaternary) is supposed to
have been responsible for the creation of morphological/structural highs and
lows. By coupling field geological survey and geophysical investigations, we
reconstructed the 3-D geological model of an inner tectonic basin of the
central Apennines, the Subequana Valley, bounded to the northeast by the
southern segment of one of the major active and seismogenic normal faults of
the Apennines, known as the Middle Aterno Valley–Subequana Valley fault system.
Our analyses revealed that, since the late Pliocene, the basin evolved in a
double half-graben configuration through a polyphase tectonic development.
An early phase, Late Pliocene–Early Pleistocene in age, was controlled by
the ENE–WSW-striking and SSE-dipping Avezzano–Bussi fault, that determined
the formation of an early depocentre towards the N–NW. Subsequently, the
main fault became the NW–SE-striking faults, which drove the formation during
the Quaternary of a new fault-related depocentre towards the NE. By
considering the available geological information, a similar structural
evolution has likely involved three close tectonic basins aligned along the
Avezzano–Bussi fault, namely the Fucino Basin, the Subequana Valley, and the
Sulmona Basin, and it has been probably experienced by other tectonic basins
of the chain. The present work therefore points out the role of pre-existing
transverse tectonic structures, inherited by previous tectonic phases, in
accommodating the ongoing tectonic deformation and, consequently, in
influencing the structural characteristics of the major active normal
faults. This has implications in terms of earthquake fault rupture
propagation and segmentation. Lastly, the morpho-tectonic setting of the
Apennine chain results from the superposition of deformation events whose
geological legacy must be considered in a wider evolutionary perspective.
Our results testify that a large-scale basin and range geomorphological
feature – often adopted for morpho-tectonic and kinematic evaluations in
active extensional contexts, as in the Apennines – just led by
range-bounding active normal faults may be actually simplistic, as it could
not be applied everywhere, owing to peculiar complexities of the local
tectonic histories
Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.