Looking Into the Entanglement Between Karst Landforms and Fault Activity in Carbonate Ridges: The Fibreno Fault System (Central Italy)

Abstract

The entanglement between active tectonics and karst systems is well-known in the literature. Karst systems are sound recorders of continental deformation in terms of brittle structures and seismic features and have been successfully used as markers for reconstructing tectonic stresses and assessing preferential directions of increased permeability in oil and gas fields. Karst systems could also be exploited to evaluate the past activity of faults bounding karst hydrostructures, thus providing useful data for the assessment of the seismic hazard of a specific area. In this work, we look into the complex relationship among karst development, recent tectonics and groundwater flow, which appear to be strongly interconnected with each other, to assess the activity of faults bounding karst hydrostructures. We focused our attention on an active karst area located in the Mesozoic and Cenozoic carbonate reliefs of the Italian central Apennines. In this context, the morphological and morphometric features of the karst landforms (dolines, dry valleys, and cave entrances), identified with geomorphological surveys, and their mutual relationship with fractures and fault segments, identified employing geostructural analysis, document stasis and deepening events in karst evolution. Such events are related to changes in the groundwater table and the consequent variation of the paleokarst base level associated with the Quaternary fault activity. A comprehensive evaluation of the evolution of karst systems at local and regional scales, considering the hydrogeological influence on base levels, allows us to use karst landforms as a proxy to unravel fault activity and evolution in Italy and in other similar karst environments.

First evidence of the Late Pleistocene—Holocene activity of the Roveto Valley Fault (Central Apennines, Italy)

“…According to the aforementioned authors, the thrust activity here ended in the Pliocene, followed by a transcurrent phase and then by extensional phase. The Differently from Carrara et al (1995a, b), Saroli et al (2006Saroli et al ( , 2012Saroli et al ( , 2022 defined fault activity as persistent throughout the Quaternary, at least along the southern fault segment (Figure 2B), named as the Posta Fibreno Fault. According to these authors, the fault activity and the related deformation field conditioned a NW-SE distribution of the dolines, pervasively distributed in the carbonate reliefs of the study area.…”

“…Carrara et al (1995a, b) stated that displacements along the fault have been supposed only for the Early Quaternary, implying the current fault's inactivity. By contrast, other authors considered the fault as active during the whole Quaternary (Roberts and Michetti, 2004;Papanikolaou et al, 2005), and more recently, recent activity has been demonstrated for the southern prolongation of the fault (i.e., the Posta Fibreno fault; Saroli et al, 2022), while further investigations defined the inactivity of the northernmost sector . These aspects are by no means trivial as for the evaluations on the fault capability, since villages are settled along the fault (Pescosolido, Balsorano, San Vincenzo Valle Roveto, Morrea, Civita d'Antino, Capistrello, etc.…”

“…According to the same authors, this would have occurred during the Early Pleistocene, after the deposition of the first order of the aforementioned Campoli Appennino alluvial fan, when the base groundwater level was close to the surface (Figure 1A). In this framework, Saroli et al (2022) provides an approximate value of the vertical movement associated with the activity of the Posta Fibreno Fault, supposedly the southern branch of the RVF. Considering that the estimated onset of karst processes is around the Early Pleistocene, the authors obtain a displacement rate in the order of 0.4-0.7 mm/year associated with the fault system.…”

“…By contrast, in the case of the 1654 earthquake (Figure 1B), detailed geological investigations to define the causative fault have never been made. In the last few years, the earthquake has been tentatively associated to the "Posta Fibreno Fault", located in the southernmost sector of the investigated area, showing evidence of the late Quaternary activity between Vicalvi and Pescosolido (Saroli et al, 2012(Saroli et al, , 2022. Seismogenic hypotheses have been recently discussed by Cucci and Cinti (2022), who reviewed the available historical, hydrological, geological, and seismological data related to the 1654 earthquake, suggesting the "Sora Fault" (mapped in the area of Sora by ITHACA Working Group, 2019 and Boncio et al, 2004) as the probable causative source.…”

Combining earth sciences with archaeology to investigate natural risks related to the cultural heritage of the Marsica region (central Apennines, Italy)

“…1). Normal fault exposures have been detected along its eastern flank, i.e., along the northern prolongation of a 24-km-long fault (Middle Liri Valley-Posta Fibreno fault, being part of Liri fault) which has been considered as active during the Late Quaternary (Saroli et al 2003(Saroli et al , 2006(Saroli et al , 2022Dixit Dominus 2020). However, recent activity of the northernmost segments of the Liri fault is debated and will be the object of Sect.…”