Scientific outputs, tools and models produced within the DEFENS project.
Outputs
Project Outputs
Scientific and technological outputs of the DEFENS project.
Publication
Paleoseismic evidence for the Mw~7 1857 earthquake along the Caggiano fault system (southern Italian Apennines)
Galli P., Bello S., Brozzetti F., Galderisi A., Naso G., Pignalosa A., Benedetti G., Comedini M., Peronace E. · June 2025
The 1857 Campania-Basilicata earthquake in the southern Italian Apennines ranks among the most catastrophic
events in Mediterranean history (Mw 7.1), with an estimated death toll ranging between 11,000 and 19,000. It
consisted of a pair of mainshocks occurring within minutes of each other, affecting a vast region between the
northern Vallo di Diano and the northern Agri Valley, two Quaternary intramontane basins separated by the
Maddalena Range. The earthquakes were likely triggered by the cascading rupture of two adjacent, aligned
normal faults, whose exact length and location are uncertain and debated, especially concerning the southern
one. This study focuses on the northern normal fault, here named Caggiano fault system, which extends NW-SE
for approximately 32 km across the Meso-Cenozoic carbonate of the Maddalena Range. After mapping the fault
scarp using 1950s aerial photos and LiDAR-derived DTM, we conducted geological field survey of the entire fault
traces, performing electrical resistivity tomography preparatory to paleoseismic trenching. Subsequently, we
excavated trenches and pits, collecting numerous samples for radiocarbon dating. Results provide conclusive
evidence of surface faulting to the post-Last Glacial Maximum-Holocene, indicating the Caggiano fault system as
a reliable candidate for the 1857 earthquake, as well as earlier events, such as the one in 1561 and previously
undocumented earthquakes in the Middle Age and Roman times. These findings represent a robust contribution
to future seismic hazard assessments, which require reliable identification and seismogenic characterization of
active fault systems.
Mapping fault architecture from depth to surface: integrating microseismicity and structural geology in low-strain Apennine regions
Lavecchia G., Brozzetti F., Bello S., de Nardis R. · July 2025
High-resolution microearthquake data provide a powerful window into active fault architecture from depth to
surface in slowly deforming regions with sparse instrumental seismicity. We integrate microseismic clusters from
enhanced catalogs with detailed structural mapping to reconstruct the 3D geometry of seismogenic extensional
faults in the Latium-Abruzzi sector of central Italy. Investigated earthquake clusters align geometrically and
kinematically with known and newly mapped normal faults showing evidence of Late Quaternary activity. The
3D model depicts a set of SW-to-SSW-dipping, non-planar faults with an average dip of ~55◦ (Sora, San Donato
Val di Comino, Villavallelonga, and Pescasseroli). Their cut-off depths deepen NNE-ward, from ~7 to ~14 km,
suggesting an underlying basal discontinuity dipping~30–35◦. Microseismic patches at the roots of these faults
are mostly elongated along dip rather than along strike. This unusual geometry suggests a stress release pattern
governed by iso-oriented anisotropic roughness and corrugations on the basal discontinuity, which may focus
upward fluid migration and trigger earthquakes along hangingwall splays. Stress inversion reveals a persistent
NE–SW tensional stress field consistent across geological and instrumental timescales. An empirical magnitudearea
relationship, accounting for both epistemic uncertainty in scaling laws and areal variability of fault surfaces,
yields maximum magnitudes between 6.0 and 6.5, consistent with the regional seismotectonic framework. These
findings provide new constraints on fault connectivity, stress distribution, and fluid-fault interactions, and help
identifying potentially seismogenic sources that may remain unrecognized when geological and seismic data are
considered separately.
Paleo‐Earthquake Fingerprints and Along‐Strike Slip Variation of the Silent Mt. Morrone Normal Fault (Central Italy): A Structural‐Geochemical Approach
Bello S., Galli P., Perna M. G., Peronace E., Messina P., Rosatelli G., Andrenacci C., Lavecchia G., Pietrolungo F., Consalvo A., Mouslopoulou V., Brozzetti F. · January 2025
This study provides insights into the tectonic evolution of the normal Mt Morrone Fault System
(MMFS) in Central Italy and highlights the utility of multidisciplinary approaches in reconstructing the seismic
history of dormant fault systems. The MMFS comprises two parallel normal faults that traverse the western
slope of Mt. Morrone, and although the system can produce M > 6 earthquakes, it has been aseismic in post
Roman times. Here, we combine geochemical analysis of carbonate fault‐scarp samples with new structural
fault data and Lidar‐based topographic analysis to provide new constraints on fault geometries and kinematics,
the paleo‐earthquake history of MMFS since the Last Glacial Maximum and its slip rates. Structural analysis
reveals kinematic similarities between the two parallel strands, reflecting their response to the same stress
regime. Rare Earth Elements analyses on 53 limestone samples reveal a minimum of eight concentration
fluctuations upscarp, here interpreted as tectonic exhumation of the fault scarp due to post LGM earthquakes.
Slip per event ranges from 30 to 110 cm typical of earthquakes with 6.3 ≤ M ≤ 6.8. Lidar analysis reveals
triangular slip profiles on both fault strands. We estimate that an earthquake with an average M= 6.5–6.6 would
have a recurrence interval of ∼2,125 ± 125 years. Slip rates were calculated to be 0.5–0.65 mm/yr on the lower
and 0.65–0.7 mm/yr on the upper fault strand, with the combined system having slip rates of 0.62–0.69 mm/yr.
Our findings indicate that both strands of the MMFS are active and accumulate slip interdependently, a finding
that is critical for seismic hazard assessment.
