Federico Cella

Normal‐fault growth, segmentation, and their relationships with crustal inheritance and rheological layering are investigated in a post‐thrusting setting of the southern sector of the Northern Apennines. We integrate 3D modeling with gravity, thermal, and seismological constraints to reconstruct the geometry and evolution of the main normal fault systems in the study area, including that responsible for the 2016–2017 central Italy earthquake sequence. Our results support a crustal extensional system in which fault growth and seismogenesis are controlled by progressive segment linkage and structural inheritance, as well as rheological and thermal layering. The normal fault network is dominated by NW‐ to NNW‐striking, high‐angle segments that offset the pre‐existing thrust stack and propagate through the upper crust. Cumulative throw profiles and displacement‐length scaling are consistent with segment interaction and linkage, and strain localization within a mechanically layered crust. Cross‐cutting relationships indicate limited, non‐systematic reactivation of pre‐existing thrust surfaces, while the spatial arrangement of recent faulting suggests localization within crustal domains inherited from the Mesozoic rift template. Projecting earthquake hypocenters onto a new gravity‐constrained balanced geological section provides an unprecedented level of detail on seismicity distribution in the Apennines. Earthquake hypocenters are concentrated between ∼3 and ∼12 km depth and broadly overlap the levels occupied by the Upper Triassic dolomite‐anhydrite succession of the Burano Formation and Mesozoic carbonates lying in the footwall of the main thrust of the region (i.e., the Monti Sibillini Thrust); the vertical distribution of seismicity further reflects rheological contrasts involving a weak phyllitic interval overlying rigid crystalline basement.

This study proposes a procedure to improve the interpretation of data from the Frequency Domain ElectroMagnetic method (FDEM), a geophysical technique with high benefit–cost ratios in archaeology. This method enables the simultaneous analysis of electrical and magnetic properties of the investigated medium, providing data as in‐phase and out‐of‐phase (quadrature) components of the electromagnetic field. Traditionally, FDEM produces individual maps for these components that are typically inspected and related to each other only visually. The proposed procedure is based on unsupervised machine learning that, by providing integrated maps of these two components, overcomes the limitations of visual inspection and streamlines the interpretative phase. The FDEM data acquired at the Torre Galli archaeological site in Calabria, Italy, were clustered using K ‐means, known for its effectiveness in partitioning densely distributed spatial data. The optimal number of clusters was determined through silhouette analysis. Once identified, the clusters were classified as either representative of the natural background or indicative of archaeological interest and mapped in real space. This analysis identified several areas with anomalous geophysical characteristics compared to the natural context, characterized by distinct ranges of EM property values, suggesting the presence of different archaeological targets, such as road, walls and iron/bronze tools, which are distributed heterogeneously in the subsoil. This classification facilitated the rapid delineation of areas with significant archaeological potential that may warrant further investigation, resulting in a reduction of both the study area size and the archaeological effort associated with excavation. A comparison of these areas with previous excavations and the results of a magnetic survey shows that the proposed procedure is promising in enhancing the efficiency and accuracy of the FDEM method for identifying areas of archaeological interest. The findings suggest a move towards automation in the interpretation process, which could improve cost‐effectiveness and time optimization in geophysical and archaeological investigations.

The relatively short‐term effects of ridge subduction may be evaluated in the Peruvian region of the recent (4 and 5 Ma) arrival of the Nazca Ridge at the subduction interface. Such effects are superposed onto—and are mostly discernible from—those of a long‐term, Cretaceous to Miocene tectonic evolution. A comprehensive two‐dimensional model was built to analyze the interaction between “young” ridge subduction and the preexisting structural framework of the overriding plate. This involved the construction of an approximately 1,000 km long and 180 km deep section integrating surface geology and available geophysical information. To constrain at depth and validate the section, we conducted forward modeling of the Bouguer anomaly using two distinct data sets and formulated a two‐dimensional density model considering the petrological properties and P‐T conditions of crustal and mantle rocks. While the deep portion of the subduction system is dominated by the Nazca Ridge flat subduction, upper plate rheology, inherited structures and stratigraphy mostly control fold and thrust belt architecture. This latter is characterized by basement‐involved thrusting and inversion tectonics. Crustal budget calculations provide shortening values ranging from 137 km (25%, considering an original crustal thickness like that of the present‐day Andean foreland) to 275 km (40%, for a rifted pre‐orogenic crust thinned by 20%). Despite the relatively large uncertainty, the obtained range of values is relevant and overall consistent with the northward decrease of shortening away from the Central Andes Orocline estimated by the restoration of vertical axis rotations obtained from paleomagnetic data.

Sediments infilling in intermontane basins in areas with high seismic activity can strongly affect ground-shaking phenomena at the surface. Estimates of thickness and density distribution within these basin infills are crucial for ground motion amplification analysis, especially where demographic growth in human settlements has implied increasing seismic risk. We employed a 3D gravity modeling technique (ITerative RESCaling—ITRESC) to investigate the Fucino Basin (Apennines, central Italy), a half-graben basin in which intense seismic activity has recently occurred. For the first time in this region, a 3D model of the Meso-Cenozoic carbonate basement morphology was retrieved through the inversion of gravity data. Taking advantage of the ITRESC technique, (1) we were able to (1) perform an integration of geophysical and geological data constraints and (2) determine a density contrast function through a data-driven process. Thus, we avoided assuming a priori information. Finally, we provided a model that honored the gravity anomalies field by integrating many different kinds of depth constraints. Our results confirmed evidence from previous studies concerning the overall shape of the basin; however, we also highlighted several local discrepancies, such as: (a) the position of several fault lines, (b) the position of the main depocenter, and (c) the isopach map. We also pointed out the existence of a new, unknown fault, and of new features concerning known faults. All of these elements provided useful contributions to the study of the tectono-sedimentary evolution of the basin, as well as key information for assessing the local site-response effects, in terms of seismic hazards.

Recent techniques of three‐dimensional (3D) imaging of potential field anomalies are effective in estimating the source position in the subsurface by exploiting both the differentiation of the field and the stability of the method. Such a processing is fast and especially suitable for detecting isolated and compact sources, as usually are those of archaeological interest. Among these methods we employed techniques that take advantage from innovative concepts like the multiscale transformation and the scaling function, going well beyond the standard procedures usually employed for data processing with archaeological purposes. We interpreted magnetic data acquired during two geophysical surveys carried out in 2008 and 2010 at Tell Barri, in north‐eastern Syria. Tell Barri is a relevant site for the history of North Mesopotamia. The earliest settlement dates back to the end of the fourth millennium bce whereas the site has been occupied – with no major breaks – until the fourteenth century ce. Based on the magnetic data interpretation, we have selected a test area as a target for an archeological excavation. The excavation found ancient structures closely matching the magnetic source revealed by the geophysical imaging. Since both the ground soil and the material of buried archaeological structures are representative of several ancient settlements in a much larger area (Upper Mesopotamia), we believe that such a geophysical approach could be successful in many archaeological sites scattered through this broad region.

In this paper, we present a new Bouguer gravity map of the Northern Tuscan offshore (central Italy), based on original gravity data acquired on the islands of the Tuscan Archipelago. Our dataset integrates 274 unpublished gravity field measurements with 126 available marine gravity data of the northern Tyrrhenian Sea. The Bouguer anomaly map shows a westward and southward increase of the regional gravity field associated with the uplift of the Moho boundary from central Apennines towards the Tyrrhenian Sea. At a local scale, several Bouguer anomalies are well associated with the igneous plutons of the Elba, Montecristo and Capraia islands, as a result of a deep density contrast between the granitoid intrusive rocks and the embedding metamorphic basement. The presented Bouguer anomaly map represents a useful tool for future studies of the complex geological and geodynamical setting of the Tuscan Archipelago and of the buried and deep igneous structures.

We analyze a wide gravity low in the Campania Active Volcanic Area and interpret it by a large and deep source distribution of partially molten, low-density material from about 8 to 30 km depth. Given the complex spatial-temporal distribution of explosive volcanism in the area, we model the gravity data consistently with several volcanological and petrological constraints. We propose two possible models: one accounts for the coexistence, within the lower/intermediate crust, of large amounts of melts and cumulates besides country rocks. It implies a layered distribution of densities and, thus, a variation with depth of percentages of silicate liquids, cumulates and country rocks. The other reflects a fractal density distribution, based on the scaling exponent estimated from the gravity data. According to this model, the gravity low would be related to a distribution of melt pockets within solid rocks. Both density distributions account for the available volcanological and seismic constraints and can be considered as end-members of possible models compatible with gravity data. Such results agree with the general views about the roots of large areas of ignimbritic volcanism worldwide. Given the prolonged history of magmatism in the Campania area since Pliocene times, we interpret the detected low-density body as a developing batholith.

We present the results of a multidisciplinary and multiscale study at Mt. Massico, Southern Italy. Mt. Massico is a carbonate horst located along the Campanian-Latial margin of the Tyrrhenian basin, bordered by two main NE–SW systems of faults, and by NW–SE and N–S trending faults. Our analysis deals with the modelling of the main NE–SW faults. These faults were capable during Plio-Pleistocene and are still active today, even though with scarce and low-energy seismicity (M_w maximum = 4.8). We inferred the pattern of the fault planes through a combined interpretation of 2-D hypocentral sections, a multiscale analysis of gravity field and geochemical data. This allowed us to characterize the geometry of these faults and infer their large depth extent. This region shows very striking gravimetric signatures, well-known Quaternary faults, moderate seismicity and a localized geothermal fluid rise. Thus, this analysis represents a valid case study for testing the effectiveness of a multidisciplinary approach, and employing it in areas with buried and/or silent faults of potential high hazard, such as in the Apennine chain.