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Fault displacement can be a source of hazard for critical infrastructures located in the nearby of a capable fault. This issue is usually addressed with zonation and avoidance strategies, but sometime the facilities have not this option. An alternative approach to assess likelihood of exceeding a certain level of displacement for pre-existing infrastructures is the Probabilistic Fault Displacement Hazard Analysis. Different empirical approaches have been proposed since the early 2000s to assess the probability of occurrence and the probability of exceedance of certain values of displacement, for both Primary and Distributed faulting, starting from the fault parameters. We propose the methodological approach used to gain the needed parameters and the results of the PFDHA applied to the Anghiari Fault, a poorly constrained NE-dipping segmented normal fault located in the Upper Tiber Valley (Italy) and belonging to the well-known Altotiberina low-angle normal fault system.In order to constrain the fault geometry and to select sites suitable for paleoseismologic trenching we performed geological survey, morphotectonic analysis and geophysical investigations. To assess the capability of the fault and its rate of activity we carried out a paleoseimic campaign, investigating several segments of the Anghiari fault. To obtain a multiscale evaluation of the fault slip rate, we collected samples to date paleosurfaces displaced by the fault with the cosmogenic nuclides methodology. At the end we performed the PFDHA obtaining curves and maps of hazard for both primary and distributed faulting, managing the uncertainties through various rupture scenario involving different fault segment.

The Italian Apennines is a slowly deforming area, despite not properly being an intraplate region. This is particularly true for the Northern Apennines, where~1ka) recurrence intervals. This makes earthquake geology a fundamental tool for characterizing the seismic hazard.The Anghiari fault is a 11 km-long segmented NE-dipping normal fault bounding the western side of the Upper Tiber Valley (Northern Apennines, Italy), and belonging to the well-known Altotiberina low-angle normal fault system. Here, we provide unprecedented evidence of the Holocene activity of the Anghiari fault through geological, geophysical and palaeoseismological investigations. The fault is composed of at least two nearly parallel splays. One splay runs at the base of the Pleistocene Anghiari ridge, downfaulting the late Quaternary alluvial deposits of the Tiber Valley against Middle Pleistocene continental deposits. The other splay is located within the Middle Pleistocene units of the Anghiari ridge. We focus on the latter. Detailed geomorphological analysis, geological mapping and near-surface geophysics, enabled us to select two sites for palaeoseismological trenching. Radiocarbon dating of faulted sediments provides constraints for late Holocene and historical surface faulting events significantly contributing to the estimation of the seismic hazard in the region.

In seismotectonic studies, seismic reflection data are a powerful tool to unravel the complex deep architecture of active faults. Such tectonic structures are usually mapped at the surface through traditional geological surveying, whilst seismic reflection data may help to trace their continuation from the near surface down to hypocentral depths. On seismic reflection data, seismic attributes are commonly used by the oil and gas industry to aid exploration. In this study, we propose using seismic attributes in seismotectonic research for the first time. The study area is a geologically complex region of central Italy, struck during 2016–2017 by a long-lasting seismic sequence, including a Mw 6.5 main shock. Three vintage seismic reflection profiles are currently the only ones available at the regional scale across the epicentral zone. These represent a singular opportunity to attempt a seismic attribute analysis by running attributes like the “energy” and the “pseudo-relief”. Our results are critical, as they provide information on the relatively deep structural setting, mapping a prominent, high-amplitude regional reflector interpreted as the top of basement, which is an important rheological boundary. Complex patterns of high-angle discontinuities crossing the reflectors have also been identified by seismic attributes. These steeply dipping fabrics are interpreted as the expression of fault zones belonging to the active normal fault systems responsible for the seismicity of the region. Such peculiar seismic signatures of faulting are consistent with the principal geological and tectonic structures exposed at surface. In addition, we also provide convincing evidence of an important primary tectonic structure currently debated in the literature (the Norcia antithetic fault) as well as several buried secondary fault splays. This work demonstrates that seismic attribute analysis, even if used on low-quality vintage 2D data, may contribute to improving the subsurface geological interpretation in areas characterized by limited and/or low-quality subsurface data but with potentially high seismic hazard.

The application of Ground Penetrating Radar (GPR) prospecting to the search of fossil structures, particularly using advanced techniques like Finite-difference time-domain (FDTD) modelling and GPR attribute analysis, is currently poorly exploited in paleontology. Here, we promote the use of such a GPR workflow at Bargiano (Umbria, central Italy), a unique paleontological site known for the discovery of cetacean skeletons, dolomitized sperm-whale cololites (Ambergrisichnu salleronae), and layered fossil assemblages. The study site is characterized by a very uneven topography shaping highly conductive clayey deposits, representing not exactly ideal conditions for GPR surveying. After generating models encompassing a real topography and variable electrical properties of media, we simulated buried fossil structures at variable depth with different size and geometry, using different operative frequencies. After obtaining information on the characteristics of reflections, investigation depth, and detectability, we provide a comparison with experimental data, also used to compute instantaneous amplitude and phase attributes. Upon depicting a peculiar GPR signature for our targets, we discuss the results in light of ground-truthing performed through trenching. Our workflow allowed us to restrict the excavation areas, extending the surface information in depth in a non-invasive way, and optimizing the field operations, necessary for the preservation of the study site.

With the aim of unveiling evidence of Late Quaternary faulting, a series of Ground Penetrating Radar (GPR) profiles were acquired across the Campotenese continental basin (Mt. Pollino region) in the southern Apennines active extensional belt (Italy). A set of forty-nine 300 MHz and 500 MHz GPR profiles, traced nearly perpendicular to a buried normal fault, were acquired and carefully processed through a customized workflow. The data interpretation allowed us to reconstruct a pseudo-3D model depicting the boundary between the Mesozoic bedrock and the sedimentary fill of the basin, which were in close proximity to the fault. Once reviewing and defining the GPR signature of faulting, we highlight in our data how near surface alluvial and colluvial sediments appear to be dislocated by a set of conjugate (west and east-dipping) discontinuities that penetrate inside the underlying Triassic dolostones. Close to the contact between the continental deposits and the bedrock, some buried scarps which offset wedge-shaped deposits are interpreted as coseismic ruptures, subsequently sealed by later deposits. Although the use of pseudo-3D GPR data implies more complexity linking the geophysical features among the radar images, we have reconstructed a reliable subsurface fault pattern, discriminating master faults and a series of secondary splays. We believe our contribution provides an improvement in the characterization of active faults in the study area which falls within the Pollino seismic gap and is considered potentially prone to severe surface faulting. Our aim is for our approach and workflow to be of inspiration for further studies in the region as well as for similar high seismic hazard areas characterized by scarcity of near-surface data.

The highest part of the Nera River basin (Central Italy) hosts significant water resources for drinking, hydroelectric, and aquaculture purposes. The river is fed by fractured large carbonate aquifers interconnected by Jurassic and Quaternary normal faults in an area characterized by high seismicity. The 30 October 2016, seismic sequence in Central Italy produced an abrupt increase in river discharge, which lasted for several months. The analysis of the recession curves well documented the processes occurring within the basal aquifer feeding the Nera River. In detail, a straight line has described the river discharge during the two years after the 2016 seismic sequence, indicating that a turbulent flow characterized the emptying process of the hydrogeological system. A permeability enhancement of the aquifer feeding the Nera River—due to cleaning of fractures and the co-seismic fracturing in the recharge area—coupled with an increase in groundwater flow velocity can explain this process. The most recent recession curves (2019 and 2020 periods) fit very well with the pre-seismic ones, indicating that after two years from the mainshock, the recession process recovered to the same pre-earthquake conditions (laminar flow). This behavior makes the hydrogeological system less vulnerable to prolonged droughts, the frequency and length of which are increasingly affecting the Apennine area of Central Italy.

In the present study, starting from original measurement stations, we created the Bouguer anomaly map of Southern Italy with a reduction density of 2670 kg m-3. We perform a regional gravity modelling at crustal scale along the trace of the CROP-04 (on-shore) and MB6 (off-shore) deep seismic reflection profiles crossing the Southern Apennines and the Southern Tyrrhenian Sea. Along the 320 km-long modelled profile, we investigate crustal-scale sources for the observed gravity anomalies. After a compelling review of the published Moho geometries in the area, that were retrieved from either active or passive seismic methods, we test them in the observed gravity field through forward modeling of the Bouguer gravity anomalies. The comparison between the different Moho interpretations shows that the steepness of the subducting slab, the position of the step between the western (Tyrrhenian) and the eastern (Adriatic) Moho and Moho depth represent the main features influencing the observed Bouguer anomalies at crustal scale.Finally, we provide a best-fitting model across both onshore and offshore areas. In the proposed best-fitting model, the wide wavelength and strong regional Bouguer anomalies correlate with the geometry of the Moho discontinuity and deep tectonic structures. On the other hand, the small-amplitude oscillations of the gravity anomalies were attributed to the low-density values of the Pliocene-Quaternary deposits both on- (e.g. the Bradanic trough) and off-shore (e.g. recent deposits in the Tyrrhenian sea bottom). Gravity minima correspond to the crustal doubling underneath the Southern Apennines where the Tyrrhenian Moho (~27 km depth) overlies the deeper Adriatic Moho (~50 km depth). The positive trend of the observed anomaly toward NE is related to the shallowing of the Adriatic Moho to depths of ~28 km in the Adriatic. Similarly, towards SW, the observed anomaly follows a positive trend towards the maxima located in the Central Tyrrhenian Sea. We model this trend as representative of crustal thinning and shallowing to values of ~12 km depth of the Tyrrhenian Moho. We also model a crustal transition from geometries and density values typical of a continental crust in the Adriatic domain towards a more oceanic structure and composition in the Tyrrhenian domain. This crustal model locates the westward flexure of the Adriatic Moho, mimicking the subduction of the Adriatic lithosphere beneath the Peri-Tyrrhenian block and locates step between the western (Tyrrhenian) and the eastern (Adriatic) Moho beneath the Apennines range.The resulted gravity forward model provide contributions to the tectonic settings understanding of the area by providing a robust crustal model ranging from the Tyrrhenian Sea to the Apulian foreland. Finally, we believe that the proposed model can serve as a starting point for future studies investigating the upper crustal geometries in the area and addressing open questions about its relations with seismicity distribution.

Fault displacement is a localized source of hazard for infrastructure located near active and capable faults, such as critical buildings and distributed facilities. This issue can be overcome through zoning and avoidance strategies, but facilities may sometimes not benefit from this option. In the last 20 years, several authors have developed a probabilistic approach to analyse this hazard, known as probabilistic fault displacement hazard analysis (PFDHA), for both principal fault and distributed rupturing. In this work, we apply the approach proposed by YOUNGS et alii (2003) to the Anghiari-Citta di Castello fault, a NE-dipping normal fault located in the northern Apennines of Italy, which shows evidence of Quaternary activity. We explore two different rupturing scenarios to obtain displacement hazard curves and maps for different probabilities of exceedance in 200 years at different distances along and from the principal fault trace for both the principal and distributed rupturing. The expected displacement values for the principal fault rupturing are up to 130 cm for a return period of 10,000 years (2% in 200 years), and the distributed rupturing hazard is 3–4% of the principal fault rupturing hazard. It is null in the footwall of the fault and slightly variable in its hanging wall as a function of distance from the fault trace and fault tip. The variability of the distributed rupturing hazard within the first hundreds of metres from the principal fault can assist to define mitigation strategies for existing facilities located in proximity of the fault.

SUMMARY Evaporites occur in various geological environments: sedimentary basins, orogenic belts, where they often act as tectonic decoupling layers, and as top-seals in hydrocarbon fields. In all cases, they affect the temperature distribution in the upper crust, as their thermal conductivity is relatively higher with respect to other sedimentary rocks. High heat conduction through evaporites enhances the geothermal gradient above the evaporitic layer and decreases it below, with potential consequences for surface heat flow, depth of the brittle–ductile transition and low-enthalpy geothermal exploitation. An accurate determination of their thermal conductivity is therefore necessary. We estimate the thermal conductivity of evaporitic rocks with a two-pronged method. First, an exhaustive review of the literature allows the determination of the conductivity for the main evaporitic minerals and of their variation with temperature. Secondly, in order to assess the effects of compositional variability, we select six samples of Triassic evaporites from the Apennines (from both outcrops and boreholes) and measure their mineralogical composition and thermal conductivity. The composition has a strong effect on conductivity, which goes from 5 W m–1 K–1 when anhydrite or dolomite are volumetrically predominant, to 2 W m–1 K–1 when gypsum is predominant. We also use various mixing models (where the rock conductivity is estimated from the mineralogical composition) and find sufficient agreement between measured and predicted values to justify the use of such models when direct measurements are not available. Finally, as an illustrative example of the thermal consequences of evaporites in the upper crust, we model the variations of temperature and surface heat flow caused by the occurrence of evaporitic layers of different thickness. The results show that the effects on crustal geotherms and the distribution of seismicity can be significant.

In the present study, we perform a gravity modelling at crustal scale along the trace of the CROP-04 (on-shore) and M-6B (off-shore) deep seismic reflection profiles, crossing the Southern Apennines and the Southern Tyrrhenian Sea (Italy). Along the 321 km-long modelled profile, we investigate the crustal-scale sources for the observed gravity anomalies through a simplified model of the crust and upper mantle across both onshore and offshore areas.After a compelling review of the published Moho geometries in the area, that were retrieved from either active or passive seismic methods, we test them in the observed gravity field through forward modelling of the Bouguer gravity anomalies. The comparison between the different Moho interpretations highlights the major contributors to the observed Bouguer gravity at the crustal scale, defining a set of starting values of these parameters for our final model.The proposed model locates the westward flexure of the Adriatic Moho, mimicking the subduction of the Adriatic lithosphere beneath the Peri-Tyrrhenian block and locates the step between the western (Tyrrhenian) and the eastern (Adriatic) Moho beneath the Apennines range providing a valuable geometrical and compositional model at the crustal scale. The model depicts a typical oceanic-to-continental crust transition in the Tyrrhenian domain and represents a solid starting base for further detailed modelling across the area.

Urban geology analyses natural risks and promotes geoheritage in urban areas. In the cities, characterized by a high cultural value, the hypogean artificial cavities, often present in the downtown, offer a unique opportunity to show the geological substratum. Moreover, these places could be a point of interest in urban trekking with the abiotic component of the landscape as a topic (geotourism). To investigate these areas, rigorous bibliographic research and a geomorphological assessment are the first steps, but, besides, non-invasive methods are new techniques increasingly in demand. In this paper, we present a multidisciplinary study on the Etruscan Well (third century B.C.), one of the most important Etruscan artefacts in Perugia (Umbria region, Central Italy). The characteristics of the sedimentary deposits outcropping along the perimeter walls have been collected. Moreover, to show the underground geoheritage, we provide a 3D model of the well and the surrounding area integrating a georeferenced laser scanner survey with ground-penetrating radar prospecting. We aim to obtain a tridimensional mapping of accessible internal rooms to depict the geological characteristics of the Etruscan Well, also revealing a surrounding network of buried galleries. The results are not only a meaningful advancement in the archaeological, geological and historical knowledge of the downtown of Perugia but are a hint for the geoheritage promotion and dissemination, providing images and 3D reconstruction of underground areas.

In this work, the crustal volume struck by the 2016-2017 seismic sequence in Central and Northern Apennines is investigated using constrained 3D inversion of the Bouguer anomaly. After a preliminary regional field removal the residual dataset is then inverted into a 3D density contrast model. With an increasing complexity in the reference geometries, we test different geological scenarios and software settings. Geometries used in the reference models were retrieved from the available geological and geophysical information in the area. Starting with a reference model encompassing turbidites, carbonates and evaporites, and basement we finally test the effects of a low-density layer at the top of the basement. The retrieved density distribution with depth is compatible with previous models. Moreover, results support the hypothesis based on borehole evidence, of a low-density upper basement across the entire area, possibly phyllitic in composition. Comparison of the resulting models with the spatial distribution at depth of M>3 seismic events between August and November 2016, allows to locate volumes with the higher concentration of seismic events. Both at shallow and deep locations, the majority of the events enucleated in volumes relatively denser while deeper events occur in a region of major density change corresponding to the top of the basement.

The 2016–2017 seismic sequence in Central Italy caused the reactivation of a complex NNW-SSE trending, WSW-dipping normal fault system associated with relevant coseismic ruptures. The seismic sequence significantly affected the groundwater circulation hosted in limestone aquifers. Based on the data available in May 2019, this work aims to contribute to understanding how the reactivation of the seismogenic faults has influenced the hydrological system of the upper Nera River basin. It appears that the seismic sequence changed the recession processes of the Nera River. Post-seismic recession curves are described by straight lines (non-darcian flow), while the pre-seismic ones follow the exponential function (darcian flow). After the earthquake, the system empties (i.e., the storage decreases) at a faster rate than before; this effect persists after more than two years from the 2016 earthquake. According to some geological cross-sections, the analysis of coseismic deformations and recession curves, a presumable increase in aquifer permeability seems to be the main factor affecting the post-earthquake river discharge. If the non-darcian recession process continues in the future, the river flow will be more variable than in the past, causing significant problems to water-using productive activities. This because, during prolonged drought periods, the fast decrease of the dynamic water storage would produce discharges lower than in the past. The results here reported can contribute to the understanding of the medium-long term evolution of this particular hydrological system as well as of other similar ones and could be useful to better managing the groundwater resources.

In this work, the crustal volume struck by the 2016–2017 seismic sequence in Central and Northern Apennines is investigated using constrained 3-D inversion of the gravity anomalies. In order to focus on the area comprising the two mainshocks of the sequence, we perform a regional field removal on the data as a preprocessing step. This residual data set is then inverted into a 3-D density contrast model. We perform a series of inversions to test different geological scenarios and parameters, with increasing complexity in the reference geometries. We first test a model comprising turbidites, carbonates and evaporites, and basement and then introduce a low-density layer at the top of the basement. The geometries are obtained in agreement with the available geological and geophysical information in the area. We found that the density distribution with depth is compatible with previous models. Moreover, results support the hypothesis based on borehole evidence of a low-density upper basement across the entire area, possibly consisting of low-grade metamorphic rocks (phyllites). Finally, we compare our modeling results to the spatial distribution at depth of major seismic events between August and November 2016. These events appear to be concentrated within the denser units at both shallow and deep locations, while the deeper events often occur in a region of major density contrast corresponding to the top of the basement.

Starting from 24 August 2016, a long seismic sequence, including nine M-w > 5.0 earthquakes, struck a wide area of the Central Italy. A large amount of geological, geodetic, and seismological data envisages a complex system of NNW-SSE trending, seismogenic normal faults. These active tectonic structures are well known at the surface and consistent with previous seismotectonic studies. In order to improve the comprehension of the seismotectonic framework of this seismic sequence, we provide a novel reconstruction of the subsurface geology of the area close to the Norcia M-w 6.5 mainshock (30 October 2016), based on previously unpublished seismic reflection profiles and available geological data. All the data have been synthesized along a 47 km long, WSW-ENE trending geological cross section, interpreted down to a depth of 12 km. Comparing the subsurface geological model with the available seismological data, we find that the majority of seismicity is confined within the sedimentary sequence and does not penetrate the underlying basement. The basement has been constrained at depths of 8 to 11 km and coincides with the cutoff of the seismicity. We have also traced the trajectories of the seismogenic normal faults activated during this seismic sequence, reconciling the high-angle (dip>65 degrees) normal faults exposed at the surface, with their angle (dip < 50 degrees) at hypocentral depths. The results of this study may be useful for better understanding the rheological properties of the seismogenic rock volume, as well as the coseismic deformations of the topographic surface observed by geodetic techniques and field mapping.

Shallow landslide failures are distributed worldwide and cause economic losses and fatalities. A proper evaluation of the possible occurrence of shallow landslides requires reliable characterization of water content. Volumetric water content (?) is commonly estimated using dielectric sensors, which use manufacturers' calibration curves developed for specific soil types. In this study, we present the experimental results achieved during a laboratory calibration of a capacitance probe (PR2/6 probe), tested on two sandy soils widely outcropping in Central Italy. The proposed equations demonstrate a more reliable estimation of ? with respect to the generalized soil equation provided by the manufacturer, which overestimates ? by up to 10 percentage points. Such overestimation could affect the evaluation of suction stress in partially saturated shallow soils affecting the slope stability analysis. Although the use of ? from correct calibration equations provides less precautionary factor of safety values, a reliable evaluation of the soil moisture condition is fundamental when mapping and predicting the spatial and temporal occurrence of shallow landslides. The use of the PR2/6 probe with the appropriate soil calibration equations in early warning monitoring systems will provide a more reliable forecast, minimizing the number of false alarms.

We present new viscosity measurements of a synthetic silicate system considered an analogue for the lava erupted on the surface of Mercury. In particular, we focus on the northern volcanic plains (NVP), which correspond to the largest lava flows on Mercury and possibly in the Solar System. High-temperature viscosity measurements were performed at both superliquidus (up to 1736 K) and subliquidus conditions (1569–1502 K) to constrain the viscosity variations as a function of crystallinity (from 0 to 28%) and shear rate (from 0.1 to 5 s-1). Melt viscosity shows moderate variations (4 –16 Pa s) in the temperature range 1736–1600 K. Experiments performed below the liquidus temperature show an increase in viscosity as shear rate increases from 0.1 to 5 s-1, resulting in a shear thinning behaviour, with a decrease in viscosity of ca. 1 log unit. The low viscosity of the studied composition may explain the ability of NVP lavas to cover long distances, on the order of hundreds of kilometres in a turbulent flow regime. Using our experimental data we estimate that lava flows with thickness of 1, 5 and 10 m are likely to have velocities of 4.8, 6.5 and 7.2 m/s respectively, on a 5° ground slope. Numerical modelling incorporating both the heat loss of the lavas and its possible crystallization during emplacement allows us to infer that high effusion rates (> 10000 m3/s) are necessary to cover the large distances indicated by satellite data from the MESSENGER spacecraft.

In seismotectonic studies, seismic reflection data are a powerful tool to unravel the complex deep architecture of active faults. Such tectonic structures are usually mapped at surface through traditional geological surveying whilst seismic reflection data may help to trace their continuation from the near-surface down to hypocentral depth. In this study, we propose the application of the seismic attributes technique, commonly used in seismic reflection exploration by oil industry, to seismotectonic research for the first time. The study area is a geologically complex region of Central Italy, recently struck by a long-lasting seismic sequence including a Mw 6.5 main-shock. A seismic reflection data-set consisting of three vintage seismic profiles, currently the only available across the epicentral zone, constitutes a singular opportunity to attempt a seismic attribute analysis. This analysis resulted in peculiar seismic signatures which generally correlate with the exposed surface geologic features, and also confirming the presence of other debated structures. These results are critical, because provide information also on the relatively deep structural setting, mapping a prominent, high amplitude regional reflector that marks the top basement, interpreted as important rheological boundary. Complex patterns of high-angle discontinuities crossing the reflectors have been also identified. These dipping fabrics are interpreted as the expression of fault zones, belonging to the active normal fault systems responsible for the seismicity of the region. This work demonstrates that seismic attribute analysis, even if used on low-quality vintage 2D data, may contribute to improve the subsurface geological interpretation of areas characterized by high seismic potential.

Emissivity and reflectance spectra have been investigated on two series of silicate glasses, having compositions belonging to alkaline and subalkaline series, covering the most common terrestrial igneous rocks. Glasses were synthesized starting from natural end-members outcropping at Vulcano Island (Aeolian Islands, Italy) and on Snake River Plain (USA). Results show that the shift of the spectra, by taking Christiansen feature (CF) as a reference point, is correlated with SiO2 content, the SCFM factor and/or the degree of polymerization state via the NBO/T and temperature. The more evolved is the composition, the more polymerized the structure, the shorter the wavelength at which CF is observable. CF shift is also dependent on temperature. The shape of the spectra discriminates alkaline character, and it is related to the evolution of Qn structural units. Vulcano alkaline series show larger amount of Q4 and Q3 species even for mafic samples compared to the subalkaline Snake River Plain series. Our results provide new and robust insights for the geochemical characterization of volcanic rocks by remote sensing, with the outlook to infer origin of magmas both on Earth as well as on terrestrial planets or rocky bodies, from emissivity and reflectance spectra.

A revised surface heat flow map of a sector of the Northern Apennines is presented, constrained by recently available thermal and petrophysical logs from 174 wells drilled for geothermal and hydrocarbon exploration purposes. The borehole temperatures have been corrected for drilling, inclination, and palaeoclimate effects. The corrected temperature data, combined with petrophysical parameters for each individual formation, have been used to derive shallow geotherms (down to a maximum depth of 8 km), which have yielded site-specific heat flow values. These values, once corrected for palaeoclimatic topographic and erosion/sedimentation effects, have been contoured by a kriging procedure to obtain the heat flow map. The map shows a clear distinction between a western zone (the Tyrrhenian Domain) of high heat flow (>150 mW m −2 ), with closely spaced heat flow isolines, and an eastern zone (the Adriatic Domain) of relatively low ( −2 ), spatially uniform heat flow. The boundary between the two zones is roughly parallel to the axis of the Apennines. Five crustal geotherms (extending to the Moho) and the corresponding rheological profiles confirm that the 70 mW m −2 isoline corresponds to a major tectonic boundary, across which the thermal, structural, and seismic properties of the lithosphere go through a significant change.

In this study, the impact event that produced the Martian Isidis basin (0–20°N and 70–100°E) was modeled using the iSALE hydrocode, and the current lithospheric structure was obtained comparing the calculated admittance from topography and gravity data, with the admittance from top-load and bottom-load flexure models. The best-fit admittance model was obtained using a bottom-load flexure with a thinned crust of 10 km, likely formed by cooling of the surficial melt pool after the impact, and an elastic thickness of 36 km. We found that the impact produced crustal excavation and thickening, surficial melt pool and temperatures >1500 K beneath the area where the free-air maxima is observed. The geometry resulting from the impact modeling is compatible with the radius of the Isidis basin. Derived thermal gradient and heat flux are in agreement with an early-Noachian epoch for the Isidis impact event and with the intense volcanic activity that followed the impact.

The discrepancy between the size of the Apenninic chain and the depth of the Adriatic foredeep is investigated using 2D flexural backstripping on well‐constrained depth‐converted cross‐sections in the Pescara basin (Central Italy). The procedure consisted of removal, uplift, unfolding and unfaulting of the Pliocene–Pleistocene foreland deposits to produce a palaeogeographic map of the basin at the end of the Messinian and to constrain sedimentary rates since the Miocene. Results are found to support the contribution of an external load to the foreland evolution together with the Apenninic chain load. The interplay of the two types of loads resulted in spatial and temporal variations of the foredeep evolution that are quantified by palaeogeographic maps and sedimentation rates obtained through backstripping. Results are interpreted as representing the effects of a southward‐migrating wave linked to slab detachment beneath the Adriatic foredeep. This procedure can be useful to investigate similar problems on other chains worldwide.

In this study, laboratory and GPR water content measurements on two sandy soils are compared. A robust procedure to constrain GPR surveys is provided, aiming to obtain accurate and reliable soil moisture information at the field scale. The application of the well-known Topp’s equation, provided good results only for water contents (θv) from 5 to 17%. Therefore, integrated analyses are mandatory to better understand the subsurface structures and the water content pattern in unsaturated zones. Data and results here presented represent the first reference for typical sandy soils outcropping in Central Italy, providing solid constraints for engineering and hydrogeological applications.

The integration of different techniques for the estimation of the volumetric water content θ in low-loss sandy soils may allow to obtain more reliable measure, after a proper evaluation of the techniques limits and their pros and cons. In particular, the integration of direct laboratory measurements performed on samples $\theta$ values measured) with geophysical data collected on a soil column using a Ground Penetrating Radar (GPR) as well as a Capacitance Probe (CP), allowed us to compare the results and evaluate their accuracy. Our experimental measures, performed on two typical sandy soil outcropping in Central Italy, show that the GPR reflected pulses provide similar permittivity $(\varepsilon_{\mathrm{r}})$ values for both soils at very low θ. The measured $\varepsilon_{r}$ values seem to progressively differ by increasing the soil moisture of the two sands. The CP shows a clear difference of measured permittivity already at lower soil moisture. As θ values in the media increase approaching the soil saturation, the CP $\varepsilon_{r}$ values measured on both the two soils show a larger difference. In conclusion, the comparison between GPR and CP measures in two selected sands under controlled condition $\pmb{(0.05\ , shows that the latter tends to overestimate $\varepsilon_{\mathrm{r}}$ on the entire range investigated. Nevertheless, if a specific laboratory calibration is carried out, as in the present work, reliable $\theta$ values estimations can be obtained by both methods. Other measurement techniques will be tested and compared in further experiments; moreover, the calibration and integration of GPR and CP is advised not only in laboratory studies, but also to better constrain possible field applications.

A series of Ground-Penetration Radar (GPR) profiles were collected on a site located in the Campotenese basin, in the active belt of the Calabro-Lucanian boundary (southern Apennines - Italy). This methodology was applied to visualize the effect of recent deformations possibly related to past ground ruptures due to historical or pre-historical earthquakes. Several 300 MHz and 500 MHz profiles perpendicular to an active normal fault were analyzed and interpreted. Some alluvial and colluvial sediments, belonging to the Middle Pleistocene basin infill, appear to be dislocated by several west and east-dipping faults. The more persuasive evidence of faulting is located in proximity of the contact between bedrock dolostones and Holocene- Pleistocene continental deposits. Despite the gaps on the data coverage and the complexity to create connections among the interpreted features across all the radargrams, we show that our approach is useful to better define and correlate the trends of faults at various scales (master faults and their splays), below the ground surface, in active tectonics areas.

The high-amplitude wide magnetic anomaly that covers a large area of the north-eastern – central Adriatic Sea in the Croatian offshore is ∼100 km wide and extends NW–SE for ∼350 km. The anomaly is located between the Dinarides and Apennines chains, in an interesting geodynamic scenario. The presence of intruded gabbroid rocks in the Croatian archipelago also contributes to making this intriguing and still not extensively investigated anomaly potentially significant to the geologic and geophysical context in which it is located. In this work, we model the Bouguer and magnetic anomalies across the Adriatic Sea. The 2D geophysical modeling was produced across four cross sections considering surface heat flow data to calculate the Curie depth. The magnetic susceptibilities and densities used for the synthetic bodies are in agreement with the literature and with those derived by previous models. The results suggest the presence of an uplifted magnetized basement with high magnetic susceptibility (0.075 SI units) to be the main contributor to the observed magnetic anomaly. This magnetic susceptibility is interpreted as representative of a gabbroid-intruded basement. The high-susceptibility basement is in lateral continuity with a relatively low susceptibility basement (0.025–0.038 SI units). The results of the geophysical modeling are compared with a conceptual geological model realized from the integration of surface, well and geophysical data, the latter concerning seismic, tomographic, magnetic and gravimetric anomalies and heat flow data. These data have been merged in an integrated data-base using MOVE software, and the geophysical modeling was performed using GM-SYS. The comparison allowed to confirm the hypothesis that the magnetic anomaly is related to the basement and to its position in the complex geodynamic evolution of the Apennines–Adriatic–Dinarides system.

In this work we report a GPR study across a tectonic discontinuity in Central Italy. The surveyed area is located in the Castelluccio depression, a tectonic basin in the Central Apennines, close to the western border of the Mt. Vettore. Its West flank is characterised by a set of W-dipping normal faults, considered active and capable of generating strong earthquakes (M w = 6.5, Galli et al., 2008 ). A secondary fault strand, already studied with paleo-seismological analysis ( Galadini and Galli, 2003 ), has been observed in the Quaternary deposits of the Prate Pala alluvial fan. We first defined the survey site using the data available in literature and referring to topographic and geological maps, evaluating also additional methodologies, such as orthophoto interpretation, geomorphologic analysis and integrating all the information in a GIS environment. In addition, we made extensive use of GPR modelling, reproducing the geometric characteristics of the inferred fault area and interpreting the synthetic profiles to recognise local geophysical indications of faulting on the radargrams. Finally, we performed a GPR survey employing antennas with different frequencies, to record both 2D Common Offset profiles and Common Mid Point (CMP) gathers for a more accurate velocity estimation of the investigated deposits. In this paper we focus on the evaluation of the most appropriated processing techniques and on data interpretation. Moreover we compare real and synthetic data, which allow us to better highlight some characteristic geophysical signatures of a shallow fault zone.

The Northern Apennines (NA) are characterized by formerly compressive structures partly overprinted by subsequent extensional structures. The area of extensional tectonics migrated eastward since the Miocene. The youngest and easternmost major expression of extension is the Alto Tiberina Fault (ATF). We estimate 2D rheological profiles across the NA, and conclude that lateral rheological crustal variations have played an important role in the formation of the ATF and similar previously active faults to the west. Lithospheric delamination and mantle degassing resulted in an easterly-migrating extension-compression boundary, coinciding at present with the ATF, where (i) the thickness of the upper crust brittle layer reaches a maximum; (ii) the critical stress difference required to initiate faulting at the base of the brittle layer is at a minimum; and (iii) the total strengths of both the brittle layer and the whole lithosphere are at a minimum. Although the location of the fault is correlated with lithospheric rheological properties, the rheology by itself does not account for the low dip (~ 20°) of the ATF. Two hypotheses are considered: (a) the low dip of the ATF is related to a rotation of the stress tensor at the time of initiation of the fault, caused by a basal shear stress (~ 100 MPa) possibly related to corner flow associated with delamination; or (b) the low dip is associated to low values of the friction coefficient (≤ 0.5) coupled with high pore pressures related to mantle degassing. Our results establishing the correlation between crustal rheology and the location of the ATF are relatively robust, as we have examined various possible compositions and rheological parameters. They also provide possible general indications on the mechanisms of localized extension in post-orogenic extensional setting. The hypotheses to account for the low dip of the ATF, on the other hand, are intended simply to suggest possible solutions worthy of further study.

In this work, we analysed the seismic noise recorded at Mt. Etna by 18 stations during the interval 2007–2015 in the frequency band 0.1–0.3 Hz, chosen to avoid contamination from volcanic tremor. Variations in time of medium seismic velocity in the range − 0.8 to 0.8% were found, mostly affecting the stations located on the volcano summit and flanks. Based on the investigated frequency content, the Δ v / v changes took place from the surface to a depth of ~ 4.5–6.5 km. To identify the source mechanism of the observed medium changes, the variations were quantitatively compared by wavelet transform coherence with volcano-tectonic and meteorological parameters. A significant relationship with meteorological parameters with seasonal periodicity (especially air temperature and snow loading) was found, probably caused by thermo-elastic strain and increasing-decreasing surface loading cycles. Moreover, a sharp medium velocity decrease, taking place in mid-December 2009 and clearly time-related to the largest volcano-tectonic strain release phenomenon of the investigated period, was also found. Such a velocity decrease was interpreted as resulting from ascent of fluids and gas exsolution taking place at the same time as the volcano-tectonic swarm.

Data gathered during the Mariner10 and MESSENGER missions are collated in this paper to classify craters into four geo-chronological units constrained to the geological map produced after MESSENGER’s flybys. From the global catalogue, we classify craters, constraining them to the geological information derived from the map. We produce a size frequency distribution (SFD) finding that all crater classes show fractal behaviour: with the number of craters inversely proportional to their diameter, the exponent of the SFD (i.e., the fractal dimension of each class) shows a variation among classes. We discuss this observation as possibly being caused by endogenic and/or exogenic phenomena. Finally, we produce an interpretative scenario where, assuming a constant flux of impactors, the slope variation could be representative of rheological changes in the target materials.

In this work, we combined multi-scale geological maps of Mercury to produce a new global map where geological units are classified based on albedo, crater density and morphological relationships with other units. To create this map, we used the 250 m/pixel mosaic of images acquired by the narrow- and wide-angle cameras onboard the MErcury Surface, Space ENviron- ment, GEochemistry, and Ranging (MESSENGER) spacecraft during its orbital phase. The geo- logical mapping is supported by digital terrain model data and surface mineralogical variation from the global mosaic of MESSENGER Mercury Atmospheric and Surface Composition Spec- trometer observations. This map comprises the global-scale intercrater plains, smooth plains and Odin-type units as reported in previous studies, as well as units we term bright intercrater plains, Caloris rough ejecta and dark material deposits. We mapped a portion of the Raditladi quadrangle (19-358N, 106-1338E) at a regional scale at a resolution of 166 m/pixel. We characterized the geological context of the area and evaluated the stratigraphic relationships between the units. To obtain a representative geological section, we analysed and corrected available topographical data. The geological cross-section derived from our regional mapping suggests that volcanic emplacement of Raditladi's inner plains followed the topography of the basin after the deposition of impact-related units (i.e. melts, breccias and rim collapse) and was driven by low-viscosity flows. Hollows that appear on Raditladi's peak ring were possibly formed from low-reflectance intercrater plains materials exposed through the peak ring unit.

In this work we study the link between the evolution of the internal structure of Vesta and thermal heating due to 26Al and 60Fe and long-lived radionuclides, taking into account the chemical differentiation of the body and the affinity of 26Al with silicates. Differentiation takes place in all scenarios in which Vesta completes its accretion in less than 1.4 Ma after the injection of 26Al into the Solar Nebula. In all those scenarios where Vesta completes its formation in less than 1 Ma from the injection of 26Al, the degree of silicate melting reaches 100 vol. % throughout the whole asteroid. If Vesta completed its formation between 1 and 1.4 Ma after 26Al injection, the degree of silicate melting exceeds 50 vol. % over the whole asteroid but reaches 100 vol. % only in the hottest, outermost part of the mantle in all scenarios where the porosity is lower than 5 vol. %. If the formation of Vesta occurred later than 1.5 Ma after the injection of 26Al, the degree of silicate melting is always lower than 50 vol. % and is limited only to a small region of the asteroid. The radiation at the surface dominates the evolution of the crust which ranges in thickness from 8 to about 30 km after 5 Ma: a layer about 3-20 km thick is composed of primitive unmelted chondritic material while a layer of about 5-10 km is eucritic., Comment: 22 pages, 3 tables, 6 figures. Accepted for publication on Meteoritics and Planetary Science, Special Issue for the Dawn Mission on the composition of Vesta

In this work, we present a 1:3,000,000-scale geologic map of the Raditladi quadrangle (H04) of Mercury. The area covers nearly 7% of the entire planet and encompasses several features of interest such as the Caloris basin, the Raditladi basin, hollow clusters and volcanic features. The mapping took advantage of the data produced during MESSENGER's orbital phase. The mapped deposits include impact-related units observed at several scales from the Caloris basin to the secondary crater chains. The Smooth Plains unit covers the majority of the area, mantling the older Intercrater Plains and Bright Intercrater Plains units. Results show that the emplacement of all the main units and the Caloris impact event, representing the main geologic events in the quadrangle, were concentrated between 3.96 and 3.72 Ga. After this intense phase, the geologic framework was modified only by local events such as impact craters and hollow formation. This map is among the first products for the detailed geologic characterization of Mercury at such a scale. It will contribute as a constraint and a support for both further local investigation and mapping, and targeting of the forthcoming BepiColombo ESA/JAXA joint exploration mission to Mercury.

We investigate a portion of the ancient (VI and IV centuries BC) polygonal walls of Amelia, in Central Italy. After the collapse of a portion of the walls which occurred in January 2006, a wide project started in order to monitor their external facade and inspect the characteristics of the internal structure, currently not clearly known. In this specific case, the preservation of such an important cultural heritage was mandatory, therefore invasive methods like drilling or archaeological essays cannot be used. For this purpose, a multidisciplinary approach represents an innovative way to shed light on their inner structure. We combine several non-invasive techniques such as Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), specifically adapted for this study, Laser Scanning and Digital Terrestrial Photogrammetry , integrated with other geomatic measures provided by a Total Station and Global Navigation Satellite Systems (GNSS). After collecting some historical information, we gather the whole datasets exploring for their integration an interpretation approach borrowed from the reflection seismic (attribute analysis and three dimensional visualization). The results give rise for the first time to the internal imaging of this ancient walls, highlighting features associable to different building styles related to different historical periods. Among the result, we define a max wall thickness of about 3.5 m for the cyclopic sector, we show details of the internal block organization and we detect low resistivity values interpretable with high water content behind the basal part of the walls. Then, quantitative analyses to assess their reliable geotechnical stability are done, integrating new geometrical constrains provided by the geophysics and geo-technical ground parameters available in literature. From this analysis, we highlight how the Amelia walls are interested, in the investigated sector, by a critical pseudo-static equilibrium.

A ground penetrating radar (GPR) survey was conducted across the Quaternary intramountain graben of the Norcia basin (Italy) in an effort to locate an active fault zone and to investigate the shallow geological structures. Measurements over an exposed (trenched) fault identify a radar signature consisting of hyperbolic diffractions in correspondence with the main fault's position. The migrated profile shows a good spatial correlation with the known fault at a control site. The average wave velocity of radar impulses in the ground was obtained by comparing with the field scans of real traces two synthetic signals, one at the hanging wall and one at the footwall of the fault. This analysis made possible to estimate the thickness of the sedimentary layers involved in the fault mechanism and the stratigraphic throw of the fault itself. The combined use of GPR across the probable northern continuation of the fault, with the information obtained with the study in the exposed fault, was used to select the location of new trench excavations. The GPR, being a relatively easy, non-invasive and high-resolution technique, can thus be used in palaeoseismological investigations, particularly for a preliminary investigation where the geological context is poorly defined.

To add information on the brittle/ductile transition of the Southern Apennine, we investigated a rheological profile of the crust along a WSW–ENE-oriented cross-section running from Neapolitan Volcanic Zone to Apulia foreland. The rheological model was obtained computing a thermal modelling and constrained by a relocalization of earthquakes of the area. Results show that the area is characterized by horizontal rheological variations, with two horizons interlayered with ductile horizons, that are quite predominant with respect to vertical ones. The horizontal stratification of lithospheric rheology has important geodynamic consequence and could provide new insights to better understand the tectonic processes which have played a major role to construct the Southern Apennine belt. Results of this study suggested that well-constrained rheological models, built integrating information from both relocated earthquakes and thermal state, could give important hints on the mechanical behaviour of the crust and its related tectonic processes.