Maceroni, Deborah

We investigated the Late Quaternary activity of a major, crustal fault affecting the southern sector of Central Apennines, i.e., the Roveto Valley Fault (also known as Liri Valley fault). This sector of the chain was hit by numerous M>5 historical seismic events. For some of these, e.g., the 1654 one (Mw 6.33), the causative seismogenic source has never been conclusively defined. Within this seismotectonic framework, the recent activity of the Roveto Valley Fault is still a matter of debate. Some authors defined its activity as ended in the Middle Pleistocene; others considered it as currently active and seismogenic at least in its southern portion. We collected new geologic and geomorphologic data along the eastern (left) flank of the Roveto Valley, where the fault crops out, and we identified evidence of displacement of alluvial fans that we attributed to the Early, Middle, and Late Pleistocene. Moreover, the analysis of the relationship between colluvial/detrital deposits, chronologically constrained by means of radiocarbon dating, allowed us to define the activation of the Roveto Valley fault also during historical times, that is, over the past few centuries. Evidence of this has been collected along a large sector of the fault trace for a length of some tens of kilometres. The results of our studies contribute to improve the knowledge of the seismotectonic setting of a large sector of the Central Apennines. Indeed, proving the current activity of the Roveto Valley fault casts new light on possible seismogenic sources of major seismicity of central Italy, potentially responsible for severe damage over a wide area and to relevant cities, Rome being among them.

Methods of Earth Sciences have been employed in archaeological sites of the Marsica region, central Italy, in two different perspectives: to enhance knowledge on past natural events which damaged/destroyed ancient settlements/monuments and to gather data useful/necessary for preservation of the local cultural heritage. Within this wide perspective, the paper deals with (i) recent archaeoseismological investigations at Alba Fucens and other sites of the Fucino Plain which add evidence of sudden building collapse to the already available (archaeoseismological and paleoseismological) data concerning seismicity of fifth-sixth century AD; (ii) archaeological investigations on remains of the Medieval church of San Bartolomeo showing that coseismic damage in 1349 caused the abandonment of part of the building and its (re)use for burials; (iii) evidence of slope instability which caused rapid mass deposition in the lowest sector of ancient Alba Fucens since around the half of the sixth century AD, inhibiting the occupation of the Roman town; (iv) capable faulting potentially affecting the westernmost sector of the huge hydraulic works made by Romans during the first-second century AD to drain former Lake Fucino.

The term active and capable fault (ACF) defines an active tectonic structure able to rupture permanently the ground surface. When an ACF represents the expression at surface of a seismogenic source, the study of an ACF involves a twofold aspect: one concerns surface faulting hazard, with engineering implications regarding infrastructures crossing the trace of a ACF, the other concerns the definition of geometric and kinematic characteristics of seismogenic sources, with implications regarding the definition of the seismogenic potential of a given active tectonic structure. Here, we show the results of geological investigations regarding two case studies in the central Apennines. The first site is located near the village of Venere dei Marsi (AQ), where the detailed characterization of geometry and kinematics of a fault splay connected to “San Benedetto dei Marsi – Gioia dei Marsi” active fault segment, allowed us to verify the effectiveness of the ACF territory zonation proposed in “Guidelines for the management of territories affected by Active and Capable Faults” promulgated by the Dipartimento della Protezione Civile Nazionale of Italy in 2015. The second case study is located close to Preci (PG), where field geological investigations were aimed to verify the presence of an ACF in the area of the Sant’Eutizio Abbey severely damaged by the 30 October 2016 Mw 6.5 seismic event, for retrofitting activities, and to characterize the Campi fault segment in terms of recent activity. This allowed to better define the geometric and kinematic characteristics of seismogenic source, responsible for the 2 February 1703 (Mw = 6.8), nucleated by the Norcia active faults system.

Negli ultimi 20 anni l’Italia centrale è stata colpita da tre sequenze sismiche che hanno causato centinaia di vittime e ingentissimi danni all’edificato, a partire da quella umbro-marchigiana del 1997. La sequenza sismica di Colfiorito-Sellano del 1997 fu la prima in Italia ad essere studiata in modo approfondito attraverso diverse metodologie di analisi, geologiche, sismologiche e geodetiche. Successivamente, il crescente avanzamento tecnologico e l’integrazione di diverse discipline e tecniche di indagine ha poi reso quello del 2009 dell’Aquila il terremoto per faglia normale meglio studiato al mondo, fino alla sequenza sismica del 2016-2017. Quest’ultima ha determinato l’impegno di decine di gruppi di ricerca italiani ed esteri nella comprensione del processo sismogenetico che ha dato luogo alla più importante sequenza sismica, in termini energetici e di vastità di area coinvolta, degli ultimi cento anni di questo settore del territorio nazionale. L’analisi della letteratura scientifica prodotta a seguito di queste sequenze sismiche evidenzia tuttavia che ad oggi rimango alcuni nodi non sciolti, alcune incertezze e diversità di interpretazione sui processi sismogenetici che le hanno causate e, più ingenerale, sul quadro sismotettonico dell’Appennino centrale. Il presente contributo ha lo scopo di mostrare il quadro delle conoscenze relative alle tre sequenze sismiche in esame; attraverso l’interpretazione delle informazioni disponibili, acquisite sia prima che dopo gli eventi sismici, e a nuove analisi sui dati raccolti durante le tre sequenze, aiuta a fornire una chiave di lettura “neotettonica” della sismicità maggiore dell’Italia centrale, nonché nuove prospettive in termini di definizione del potenziale sismico associabile alle principali sorgenti sismogenetiche.