We present an interpretation of the eastern half portion of the CROP 11 line, a deep reflection seismic profile 265 km long that cuts across the central Apennines from the Tyrrhenian coast to the ...Adriatic coast. In the study area the line cuts across a pile of thrust sheets that underwent tectonic transport between the Messinian and the Pleistocene. In its easternmost part, the line runs through the Plio‐Pleistocene deposits of the Adriatic foredeep. In the foreland region the CROP 11 line integrates previous information on the crustal structure derived from petroleum exploration and from deep seismic sounding refraction experiments. In particular, the CROP 11 line confirms the existence of a very thick sedimentary sequence underlying the Mesozoic‐Tertiary carbonates of the Apulia Platform interpreted as the Paleozoic‐Triassic sedimentary cover of a pre‐Cambrian crystalline basement. In the mountain chain, where the base thrust of the orogenic wedge reaches a depth of about 25 km, this sedimentary sequence appears to be the deepest geological unit incorporated in the thrust system. This interpretation of the CROP 11 profile suggests an unusual thin‐skin tectonic style implying the detachment from the original basement and the incorporation in the post‐Tortonian tectonic wedge of a very thick Paleozoic‐Triassic sedimentary sequence possibly affected by low‐grade metamorphism in the lower part. Other new suggestions from the CROP 11 seismic data concern the origin of the Fucino basin, one of the most remarkable Plio‐Pleistocene intramontane basins. The normal faults bordering this structural depression, as other important normal faults present in the central Apennines (e.g., the Caramanico fault system in the Majella region), seem to have been controlled by gravitational‐collapse processes driven by uplift during crustal shortening rather than by a generalized extension subsequent to the Apennine compression, as usually reported in the geological literature. If this interpretation is correct, the strong seismic activity in correspondence to the Apennine watershed may be related to the very recent increase in the structural relief caused by an out‐of‐sequence propagation of the active thrusts.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Archaeological areas in the mountain region of central Italy can be seriously threatened by geological hazards, and efforts are required to preserve cultural heritage. The Lucus Angitiae is a ...pre-Roman site located along the western edge of the Fucino Basin, the largest continental depression of central Apennines. The carbonate slope overhanging the area is affected by active rockfall processes from two main rock escarpments. In this paper, rockfall assessment was pursued through a 3D kinematic modelling, performed by adopting a probabilistic approach. Specific attention was dedicated to the choice and calibration of the input data, based on field evidence and a literature review. Two different sizes of wedge-shaped rock blocks were identified on rock escarpments, and specific stability analyses were performed. Sensitivity analyses accounting for possible triggering factors, such as water pressure increase and seismic action, were also carried out, together with an investigation of the seismological characteristics of the area. The results of the numerical simulations were used to design effective countermeasures in the framework of a mitigation plan for protection of the archaeological site. Finally, clues of gravity-driven slope deformations at the slope scale were documented, framing the rockfall process in a wider geological scenario.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Along the Italian peninsula adjoin two crustal domains, peri‐Tyrrhenian and Adriatic, whose boundary is not univocal in central Italy. In this area, we attempt to map the extent of the Moho in the ...two terrains from variations of the travel time difference between the direct P wave and the P‐to‐S wave converted at the crust‐mantle boundary, called PsMoho. We use teleseismic receiver functions computed at 38 broad‐band stations in this and previous studies, and assigned each of the recording sites to the Adriatic or peri‐Tyrrhenian terrains based on station location, geologic and geophysical data and interpretation, and consistency of delays with the regional Moho trend. The results of the present study show that the PsMoho arrival time varies from 2.3 to 4.1 s in the peri‐Tyrrhenian domain and from 3.7 to 5.5 s in the Adriatic domain. As expected, the lowest time difference is observed along the Tyrrhenian coastline and the largest values are observed in the axial zone of the Apennine chain. A key new result of this study is a sharp E‐W boundary in the Adriatic domain that separates a deeper Moho north of about 42°N latitude from a shallower Moho to the south. This feature is constrained for a length of about 40 km by the observations available in this study. The E‐W boundary requires a revision of prior mapping of the Moho in central Italy and supports previous hypotheses of lithosphere segmentation.
Key Points
Delay of Moho conversions in central Italy are computed at 24 stations
Seismic stations are assigned to the Adriatic and peri‐Tyrrhenian crust
An E‐W oriented transition in the Adriatic Moho is inferred
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A pre-existing and inherited geostructural setting plays a fundamental role in preparing and developing large-scale slope deformational processes. These structures affect the kinematics of the ...process, the geometrical characteristics, and the geomorphological evolution. In the Apennine Belt, several deep-seated gravitational slope deformations (DSGSDs) that have evolved under a clear structural control have been recognized during the last decades, but none with a continuous and well-defined basal shear zone (BSZ). The structurally-controlled DSGSD of Luco dei Marsi represents the first case of a DSGSD in the Apennine Belt with a well-defined BSZ. Starting from a detailed study of the process and the reconstruction of a morpho-evolutionary model of the slope, a series of numerical modelings were performed for the study of the DSGSD. The analyses allowed us to reconstruct: (i) the mechanism of the process, (ii) the rheological behavior of the rock mass, and (iii) the main predisposing factors of the gravitational deformation. Numerical modeling has demonstrated the significant role played by the inherited structures on the DSGSD and, in particular, the importance of an intensely jointed stratigraphic level in the development of the BSZ.
This paper deals with the origin of the Pretare clastic deposit (PRA), which crops out along the Morricone fluvial valley in the Central Apennines of Italy. With the aim of deciphering the genesis of ...the PRA deposit, geological s.l. and geomorphological analyses were carried out allowing for the interpretation of the PRA deposit as a rock avalanche. Furthermore, geological cross sections constrained by well-log and field survey data, together with stratigraphic, sedimentologic, and morphometric analyses, allowed us to assign the deposit to a catastrophic rock slope failure, which occurred during a cold climate of the Late Pleistocene. Several issues concerning the propagation mechanisms were inferred from the mapping of 350 boulders over the entire accumulation area and from the measure of the morphometric parameters of the landslide body. We also performed a restoration of the potential source area by comparing the reconstructed pre- and post-failure DEMs. A missing volume of 8.41 × 106 m3 was estimated on the south-eastern side of the Vettore Mt., which is consistent with the deposit volume computed from the geological interpretation (10.56 × 106 m3). The outcomes of this study provide useful insights for a better understanding of the Quaternary morpho-evolution of the Central Apennines area where analogous rock avalanche events marked the recent evolution of the belt.
The ancient Appia route was built across central‐southern Italy between the fourth and second century before the common era (B.C.E.). At the Aurunci Mountain Pass, the route crosses carbonate ridges ...that provided the raw material used to pave the road in the first century C.E. This material was replaced with lava blocks of unknown origin in the third century C.E. The study area is at least 50 km from the main volcanic centers along the peri‐Tyrrhenian side of Italy, such as the Colli Albani, Roccamonfina, and Middle Latin Valley volcanoes. The main objective of this research was the chemical–petrographic and isotopic characterization of rock samples from the Appia flagstones to unravel their possible provenance. The analytical procedure included scanning electron microscope and electron microprobe analyses and 87Sr/86Sr–143Nd/144Nd isotopic measurements. Samples taken from unknown quarries found in the Middle Latin Valley volcanic field underwent the same analyses. After comparing the analysis results with data from the literature, the most likely source area was identified with the Roccamonfina precaldera ultrapotassic sequence. The availability and use of volcanic resources for the construction and maintenance of the ancient Appia route in the investigated territories are only outlined in this work and deserve further study.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Physical properties and mechanical parameters of intact rocks are essential in defining geomechanical characteristics of rock masses. The latter are fundamental in the geotechnical design and ...numerical modelling of engineering-geological applications involving slope stability analyses as well as the design of dams, foundations, tunnels, open and underground mines, nuclear storage repository etc. Time and financial constraints of many projects often do not allow to perform all the laboratory tests necessary for physical-mechanical characterization of the rock matrix. In these cases, existing published data are the only tools for appropriate definition of the geomechanical characteristics of the intact rocks and subsequent development of engineering-geological performances.
This paper reports the values of major physical properties and mechanical parameters for several intact rock samples of limestone, collected from the Central Apennines region (Italy). The main physical properties measured for the rock samples are unit weight, density, and porosity. The mechanical parameters derived from the laboratory tests on the samples include uniaxial compressive strength, cohesion, friction angle, tensile strength, elastic modulus, and Poisson's ratio. Only for a few of samples, the index parameters (point load index) and the dynamic characteristics (P-wave velocity) were also measured. The laboratory tests for these samples were performed following the standards by the International Society for Rock Mechanics (ISRM).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper focuses on Deep-Seated Gravitational Slope Deformations (DSGSDs) identified in the Molise region (Italy), along the central-southern sector of the Apennines chain. These phenomena were ...detected and mapped through a combination of aerial-photo interpretation, morphological analyses, and field surveys, integrated through satellite SAR interferometry (InSAR). The obtained general map is organized in different sections: inventory map with identification of DSGSDs and main geological and orographic features, geostructural scheme, representative cross sections, list and characteristics of DSGSDs, geomorphometric maps, landslides map, and seismotectonic setting. This study allowed us to realize a complete inventory of DSGSDs in the Molise region and define the main characteristics of each phenomenon. Through this research, it was possible to establish a general correlation between the analyzed deformations and the geological and geomorphological setting of the region as well as with its geodynamic context.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A detailed analysis of the earthquake effects on the urban area of Rome has been conducted for the L’Aquila sequence, which occurred in April 2009, by using an online macroseismic questionnaire. ...Intensity residuals calculated using the mainshock and four aftershocks are analyzed in light of a very accurate and original geological reconstruction of the subsoil of Rome based on a large amount of wells. The aim of this work is to highlight ground motion amplification areas and to find a correlation with the geological settings at a subregional scale, putting in evidence the extreme complexity of the phenomenon and the difficulty of making a simplified model. Correlations between amplification areas and both near-surface and deep geology were found. Moreover, the detailed scale of investigation has permitted us to find a correlation between seismic amplification in recent alluvial settings and subsiding zones, and between heard seismic sound and Tiber alluvial sediments.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The topic of this research consists in the description of landscape modifications occurring from the 4th century BCE to the 19th century CE as a consequence of quarrying activities on carbonate ...slopes along a tract of the ancient Appia route crossing the central Apennine belt at the Aurunci Mountain pass (Lazio region, central Italy).
The main objectives were to discern different quarrying phases and techniques, quantify quarrying activities and understand the role of quarrying in create morphological features.
Multidisciplinary studies were completed including aerial photogrammetry, geoarchaeological field surveys, morphometric characterization of quarry areas, structural analysis of rock outcrops aided by terrestrial photogrammetry, GPS measurements.
The results of this study show how the local geomorpological and tectonic setting determined which kinds of extractable rock material, i.e., rock blocks or breccias, were used for different purposes. Moreover, different phases of extraction were evidenced. A main Roman quarrying phase, lasting between the 4th century BCE and the 1st century CE, was recognized as taking place over eight quarry areas. These are delimited by sharp edges and have regular shapes, revealing in some cases a staircase-like morphological profile, and are characterized by similar volumes of extracted rock material. A later quarrying phase —the Bourbon Age, 19th century CE—is assumed to be evidenced instead by five quarries with a peculiar semi-elliptical shape and different volumes of carved material. Seven quarries were found to be of uncertain age.
The quarry system described in this paper, together with geomorphological records of slope cuts, terraced surfaces, and the remains of retaining walls, represents a unique and important example of anthropogenic landscape modification in the territory of the central Apennines caused by the construction and maintenance of a Roman road over the centuries. This could be relevant for further studies on the relations between natural environments and the development of civilisation. In addition, the multi-methodological analyses of geomorphological records originated by quarrying activities may be considered for the characterization of similar quarry landscapes.
•Geomorphology of the Aurunci Pass, crossed by the ancient Appia route, features intense quarrying.•Geoarchaeological, morphometric and topographic analyses outlined several quarry types.•Two quarrying phases (Roman and Bourbon) were outlined causing different landscape modifications.•Anthropogenic geomorphological records include terracing, slope cuts, retaining walls.•An original geoarchaeological maps was reconstructed to increase the value of the site.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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