A signifi cant uncertainty exists in the defi -
nition of both surface pattern and subsurface
continuity (i.e., coupling vs. decoupling)
of active normal faults in the Apennines. In
this study, we investigated the epicentral area
of the MS = 6.9, 1980 Irpinia earthquake—
one of the most destructive historical earthquakes
in Italy—based on detailed topography
analyses, morphostratigraphic and
structural data, and new age constraints from
Quaternary deposits. The active tectonic behavior
of the study area is controlled by a
series of subparallel, mainly WNW-ESE– to
NW-SE–trending, dominantly extensional
faults spanning over the southern Apennines
axial belt. A large part of the active fault
strands is characterized by a subdued topographic
expression, as a result of the young
age of extensional faulting initiation, and of
relatively low mean slip rates. In addition,
as already known from long historical seismicity
records elsewhere, long-lasting quiescence
might alternate with clusters of closely
spaced, strong earthquakes. The long-term
morphostratigraphic record confi rms that
long-lasting quiescence may punctuate fault
activity, with major implications for seismic
hazard assessment. The relatively smallsized
cumulative fault throws estimated by
surface evidence contrast with subsurface
information provided by crustal-scale cross
sections and seismological evidence, which
both suggest the occurrence at depth of largedisplacement,
mature fault zones capable of
nucleating large earthquakes. Furthermore,
although the surface distribution of active
fault strands overlaps the belt affected by
present-day low-magnitude seismicity and
by large historical earthquakes, a mismatch
in the attitude and kinematics of shallow versus
deep faults is unraveled by a comparison
of surface geological versus seismological
data sets. This feature suggests a decoupling
between surface and deep fault zones, and
that outcropping fault planes cannot always
be straightforwardly traced down to hypocentral
depths, particularly in fold-andthrust
belts characterized by strong rheological
contrasts. On the other hand, stress
inversion from outcropping active faults and
from earthquake focal mechanisms indicates
a general consistency of the stress fi eld, thus
suggesting that a homogeneous late Quaternary
extensional regime produces complex
reactivation of the inherited, articulated fault
network affecting different structural levels
of the southern Apennine