Late Quaternary Tectonics along the Peri-Adriatic Sector of the Apenninic Chain (Central-Southern Italy): Inspecting Active Shortening through Topographic Relief and Fluvial Network Analyses

Abstract

Active compressional tectonics along the outer front of the Apenninic-Maghrebian chain (Italy) is well documented along the northern and central segments and in Sicily. On the other hand, the Southern Apenninic Outer Front (SAOF) orogenic activity is well established only until the Lower-Middle Pleistocene. We address the hypothesis of its subsequent late Quaternary activity in central-southern Italy (Abruzzo and Molise regions). We integrated topographic and fluvial network analyses along with morphotectonic investigation of fluvial terraces to identify evidence of differential rock uplift. We compared the results with the main geolithological units, known structural elements, and long-term deformation history from seismic line interpretation. We found variable evidence suggesting localized rock uplift in the Abruzzo region along the SAOF (Abruzzo Citeriore Basal Thrust segment) and inward structures on its hanging wall (Casoli-Bomba high), as well as along part of the Struttura Costiera thrust. Middle-to-Late Pleistocene deformation is constrained by terrace tilting and disruption along the Pescara river. Localized shortening along segments of the Apenninic Outer Front could explain the observed pattern of anomalies which is difficult to explain with long-wavelength regional uplift alone. Our reconstruction is consistent with the long-term deformation of the area and agrees with its seismotectonic setting. Despite the low deformation rate context and the peculiar geological setting which challenges the interpretation of the topographic and geomorphic signals, this study compels reconsideration, in terms of seismic hazard assessment, of the existence of late Quaternary active thrusting in central-southern Italy.

Lithospheric double shear zone unveiled by microseismicity in a region of slow deformation

“…2 b (Red = reverse, blue = normal, green = strike-slip, light yellow = unknown kinematics); green dots = strike-slip Family1 with SW–NE P-axes trending; green stars = strike-slip Family2 (deep-SS) with NNW–SSE P-axes trending; OEF = trace of Outcropping west-dipping Extensional Front. The yellow lines enveloping hypocenters and focal mechanisms offer a section view of the ABT (T1) and the underlying hidden lithospheric thrust identified in this paper (T2); the Moho depth line is from Di Stefano et al 69 . ( d ) Detail from transects E showing the intersection zone between T1 and T1-splay; the hypocenters from EQS-Catalog are projected with a half-width of 2.5 km.…”

“…The prevalent deformation regime (reverse or wrench faulting) of the fold-and-thrust belt at the ABT hanging wall is still debated in the literature. Although active shortening perpendicular to the ABT is well supported by morphotectonic [67][68][69] and GPS data 25,70,71 , constraints from focal mechanisms 42,43,72 are more controversial due to the presence of strike-slip mechanisms for some of the major sequences (i.e., Cesena-Forlì 1993 and Ancona 1972). The presence of these FMs has been variously interpreted in the literature.…”

Geo-archaeology, archaeometry, and history of a seismic-endangered historical site in central Apennines (Italy)

“…The study area falls inside two different seismogenic zones: the Morrone Porrara Fault System (hereinafter MPFS) [20,21] and the Abruzzo Citeriore Basal Thrust (ACBT) in [21] (Additional file 2: Fig. S1) the first belonging to the extensional domain of the central Apennines and the latter to the compressional seismogenic province of Italy [22][23][24][25][26].…”

“…No later ruptures are known on this fault system. The second area corresponds to the compressional seismogenic structure of the ACBT [21], extending towards the Adriatic coast. ACBT might be considered responsible for destructive historical earthquakes such as the 1706 Maiella earthquake (M w 6.8, X-XI MCS), the 1881 Orsogna (M w 5.6, VIII MCS), and the 1933 Pacentro (M w 6.0, IX MCS) (Table 1) [10,11,21,33].…”

The Attenuation and Scattering Signature of Fluid Reservoirs and Tectonic Interactions in the Central‐Southern Apennines (Italy)

“…Across peninsular Italy, the W‐ and E‐ dipping faults bound an upper‐crust extensional seismogenic domain comprising most earthquakes of the Italian seismic catalog (Figure 1b, Lavecchia et al., 2021). The intra‐Apennine extensional domain overlays a deeper compressive province developed at the hanging wall of the west‐dipping outermost front of the Apennine compressional system (de Nardis et al., 2022; Ferrarini et al., 2021). Finally, the E‐W striking transcurrent faults outcropping in the Gargano area and deepening toward the west (Argnani et al., 2009) define a strike‐slip domain below the compressional one and contribute to the high seismic hazard of Central Italy.…”