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The relationships between hillslope and fluvial processes were studied in a mountainous area of the Northern Apennines (Italy) where intermittent landslide activity has interacted for a long time with river morphodynamics. The aim of the study was to analyse such relationships in two study sites of the Scoltenna catchment. The sites were analysed in detail and monitored through time. A long-term analysis was carried out based on multitemporal photointerpretation of aerial photos. Slope morphological changes and land use modifications since 1954 were detected and compared with the evolution of the channel morphology. A short-term analysis was also performed based on two monitoring campaigns accomplished in 2021 and 2022 in order to detect possible slope displacements and channel-bed-level changes. The techniques used are global navigation satellite systems and drone photogrammetry accompanied by geomorphological surveys and mapping. The multitemporal data collected allowed us to characterise slope surface deformations and quantify morphological changes. The combination of various techniques of remote and proximal sensing proved to be a useful tool for the analysis of the surface deformations and for the investigation of the interaction between slope and fluvial dynamics, showing the important role of fluvial processes in the remobilisation of the landslide toe causing the displacement of a significant volume of sediment into the stream. [ABSTRACT FROM AUTHOR]

Landslides pose significant risks to towns and villages in Southern Italy, including the San Marco dei Cavoti hamlet (Benevento, Campania), where settlements have expanded into areas threatened by landslides, leading to property damage, disruption to the social fabric and loss of life. This study aims to investigate the surface deformations in the area using Differential Interferometry SAR (DInSAR) analysis on COSMO-SkyMed radar imagery and to assess the potential implications for landslide activity. The DInSAR analysis methodology allowed us to obtain high-precision results presented as time series diagrams and maps of cumulative displacement for the study area. Furthermore, the displacement rates derived from the DInSAR analysis were decomposed into vertical and horizontal components to provide better insights into the slope processes and their potential impacts on the San Marco dei Cavoti hamlet. Our significant findings revealed active slope movements and the uphill enlargement of previously inventoried landslides threatening the San Marco dei Cavoti hamlet. These insights contribute to a better understanding of the landslide dynamics in the region and highlight the areas that may require further investigation or intervention measures. In conclusion, this study demonstrates the effectiveness of DInSAR analysis in providing valuable insights into landslide dynamics and informing potential mitigation measures for at-risk communities. This technique could be applied to other landslide-prone regions to support informed decision-making and enhance the safety and resilience of affected communities. [ABSTRACT FROM AUTHOR]

Geodetic data can detect and estimate deformation signals and rates due to natural and anthropogenic phenomena. In the present study, we focus on northeastern Italy, an area characterized by ~1.5–3 mm/yr of convergence rates due to the collision of Adria-Eurasia plates and active subsidence along the coasts. To define the rates and trends of tectonic and subsidence signals, we use a Multi-Temporal InSAR (MT-InSAR) approach called the Stanford Method for Persistent Scatterers (StaMPS), which is based on the detection of coherent and temporally stable pixels in a stack of single-master differential interferograms. We use Sentinel-1 SAR images along ascending and descending orbits spanning the 2015–2019 temporal interval as inputs for Persistent Scatterers InSAR (PSI) processing. We apply spatial-temporal filters and post-processing steps to reduce unrealistic results. Finally, we calibrate InSAR measurements using GNSS velocities derived from permanent stations available in the study area. Our results consist of mean ground velocity maps showing the displacement rates along the radar Line-Of-Sight for each satellite track, from which we estimate the east–west and vertical velocity components. Our results provide a detailed and original view of active vertical and horizontal displacement rates over the whole region, allowing the detection of spatial velocity gradients, which are particularly relevant to a better understanding of the seismogenic potential of the area. As regards the subsidence along the coasts, our measurements confirm the correlation between subsidence and the geological setting of the study area, with rates of ~2–4 mm/yr between the Venezia and Marano lagoons, and lower than 1 mm/yr near Grado. [ABSTRACT FROM AUTHOR]

New geological and morphotectonic surface data coupled with the revision of the ENI-Exploration & Production seismic lines, made it possible to review the tectonic structure of the Pliocene-Quaternary front of the eastern Southern Alps in the area between the Cellina River and the Tagliamento River (central Carnic Prealps, NE Italy). The eastern Southern Alps are a SE-verging fold and thrust belt in activity from the middle Miocene to the Present. The presence of Paleogene structural inheritances influenced the current structural arrangement of the thrust-belt and the potential seismogenesis, supporting segmentation of the Neoalpine external front. In particular, the presence of the NW-SE trending Mt.Ciaurlec – Palmanova – Pozzuolo structural high, inherited from the W-ward propagation of the External Dinarides during Paleogene, generated lateral lithological facies change and influenced not only the undulation between the Neogene-Quaternary Maniago-Meduno and Toppo-Forgaria Thrusts, but also the segmentation of the outermost portion of the Neoalpine external front consisting into two segments with different geometric and structural characteristics: 1) the ENE-WSW striking Arba-Sequals segment that runs buried under the upper Pleistocene sequences of the piedmont Friuli plain; 2) the W-E Ragogna segment that shows widespread evidence of surface deformation of the Last Glacial Maximum (LGM) alluvial plain. In particular, the long-lasting activity of the Ragogna segment is testified by the late Miocene-Middle Pleistocene angular unconformities, forced drainage anomalies and tilted and uplifted Quaternary palaeosurfaces. A discussion on the seismogenic potential of the investigated structures is proposed. • The active front of eastern Southern Alps in the carnic Prealps (NE Italy) is segmented. • The Paleogene inheritances influenced the present structural architecture of ESA Neogene-Quaternary active front. • Seismogenic potential of each active structure has been evaluated. [ABSTRACT FROM AUTHOR]

Large magnitude earthquakes produce complex surface deformations, which are typically mapped by field geologists within the months following the mainshock. We present detailed maps of the surface deformation pattern produced by the M. Vettore Fault System during the October 2016 earthquakes in central Italy, derived from ALOS-2 SAR data, via DInSAR technique. On these maps, we trace a set of cross-sections to analyse the coseismic vertical displacement, essential to identify both surface fault ruptures and off-fault deformations. At a local scale, we identify a large number of surface ruptures, in agreement with those observed in the field. At a larger scale, the inferred coseismic deformation shows a typical long-wavelength convex curvature of the subsiding block, not directly recognizable in the field. The detection of deformation patterns from DInSAR technique can furnish important constraints on the activated fault segments, their spatial distribution and interaction soon after the seismic events. Thanks to the large availability of satellite SAR acquisitions, the proposed methodological approach can be potentially applied to worldwide earthquakes (according to the environmental characteristics of the sensed scene) to provide a wider and faster picture of surface ruptures. Thus, the derived information can be crucial for emergency management by civil protection and helpful to drive and support the geological field surveys during an ongoing seismic crisis. [ABSTRACT FROM AUTHOR]

Using template matching and GPS data, we investigate the evolution of seismicity and observable deformation in Central Apennines. Seismicity appears more persistent at the base of the seismogenic layer than in the shallower crust. Diffuse activity is reported on segments at depth, alternating along strike with apparent quiescence on segments that experienced one or more Mw6+ earthquakes in 1997, 2009, and 2016. Central Apennines are likely underlain by a sizeable shear zone with areas of diffuse seismicity bounding shallow normal faults where Mw6+ earthquakes occurred. The deformation observed at the surface seems to follow the seismicity variations at the base of seismogenic layer along the Apenninic chain. Principal and independent component analyses of GPS data exhibit a transient when the 2016 foreshock sequence starts. This transient propagated northward from the Campotosto fault up to the Alto Tiberina fault system and has likely loaded the Mw6+ 2016 earthquake sequence. Plain Language Summary: We use a nonstandard method for the detection of microseismicity at depth augmenting the available catalog. The enhanced seismicity distribution is coupled with the observable deformation on a geodetic network of continuous GPS to infer a better comprehension of the earthquake behavior. The earthquake patterns in Central Apennines reveal a segmentation at depth along an almost flat base of seismogenic layer with alternating low and high seismicity rate segments. The deformation recorded at the surface seems to follow the seismicity variations at the base of seismogenic layer along the Apenninic chain also determining a possible seismic‐aseismic mode. We suggest that aseismic deformation has a fundamental role in the tectonic loading and that seismicity, even if heterogeneously distributed, could represent a tracer of it. This conclusion is also supported by the evidence of a transient propagating from south to north during the 2016 Central Italy sequence. Key Points: Subhorizontal shear zone beneath the shallow normal faults of Central Apennines is segmented into high and low seismicity rate strandsRate changes in seismicity are time correlated with a transient deformation observed before the 2016 Central Italy sequenceMw5+ earthquakes on the Campotosto fault highlight a connection between high‐rate shear zone segments and locked fault patches [ABSTRACT FROM AUTHOR]

This paper describes the results of a 2D and 3D numerical modeling carried out on an unstable natural rock slope (volume = 110,000–335,000 m3) located in north-eastern Italy (Friuli Venezia Giulia Region). It was aimed at investigating the mechanical behavior and internal rock mass damage of the unstable slope before the collapse. The numerical simulations testify that the stability condition of the slope is close to the limit equilibrium (strength reduction factor, SRF = 1.03–1.13), as demonstrated by the considerable rock mass damage observed on the field. The overall mechanical behavior of the slope is mainly governed by the kinematic conditions of the secondary internal blocks, which, in turn, depend on the geometry and mechanical properties of the major discontinuities that delimit the adjacent blocks. Slope failure is achieved through internal rock mass damage represented by internal shear and tensile ruptures localized in correspondence with over-stressed zones. The failure mechanism is characterized by sliding along pre-existing discontinuities and inner damage in the form of the enucleation of shear bands that originate internal secondary failure surfaces and/or damaged rock mass zones. The stress–strain modeling predicts intense slope deformations in zones where rock mass damage actually occurred. This paper emphasizes the decisive connection between the geomechanical field survey and numerical modeling. The comparison of surface geological data acquired on the field with the mechanical indicators obtained from the numerical analyses can significantly improve knowledge of the rock mass damage process that involves unstable slopes approaching failure condition. [ABSTRACT FROM AUTHOR]

A sequence of earthquake events consisting of three large shocks occurred in Central Italy from August to October in 2016 with the duration of almost 2 months. The preliminary study on the seismic mechanism suggests that the sequence of events is the result from the activity of the SW dipping Mt Bove–Mt Vettore–Mt Gorzano normal fault system. For investigation and understanding of the coseismic faulting of the seismogenic fault alignment, we collect a set of comprehensive satellite observations including the Sentinel-1A, ALOS-2/PALSAR-2 and GPS data to map the coseismic surface deformation and estimate the source models in this study. The derived faulting model for the first Amatrice event is characterized by two distinct slip asperities suggesting that it is a predominantly normal dip-slip motion with slight strike-slip component. The second event, Visso earthquake is almost a purely normal rupture. The third Norcia event is dominated by the normal dip-slip rupture of the seismogenic fault, and has propagated up to the ground with significant slip. The three faulting models are then utilized to quantify the Coulomb failure stress (CFS) change over the seismic zone. First, the CFS change on the subsequent two seismogenic faults of the earthquake sequence is estimated, and the derived positive CFS change induced by the preceding earthquakes suggests that the early events have positive effects on triggering the subsequent seismicity. We then explore the response relation of the aftershocks including 961 events with magnitudes larger than M 3.0 to the CFS change over the seismic zone. It suggests that the rupture pattern of the aftershocks is similar to the major shocks with predominantly normal dip-slip. To assess the risk of the future seismic hazard, we analyse quantitatively the spatial distribution of aftershock occurrence and CFS transfer at the seismogenic depth, indicating that the ruptures of the three major shocks do partly release the accumulated strain on the associated fault alignment as well as the dense aftershock, but the CFS increase zone with few aftershocks in the southwest of the eastern Quaternary fault alignment of Central Italy poses the potential of further rupture. In particular, the distribution of aftershock migration also suggests that the north extension of the Mt Bove fault is the potential zone with rupture risk. [ABSTRACT FROM AUTHOR]

Arcuate fold-and-thrust belts have been extensively studied in the literature. Less attention, however, has been paid to the characteristics of local-scale arcuate structures, meaning 5–10 km long fold or thrust traces that display map-view curvature. Nevertheless, detailed investigation of small arcuate structures hosted in major arcs can contribute to understanding the pervasiveness of deformation mechanisms. We performed a combined geological and palaeomagnetic study on 21 sites from a c. 60 km2 area in the Northern Apennines in order to analyse minor arcs at a kilometric scale. As evidenced by the geological and structural analysis performed on the 21 sites, the fold axial trend changes from N–S to NW–SE in the study area. The comparison with palaeomagnetic results shows the lack of correlation between vertical axis rotations and fold axial trends. As a consequence, the minor arcuate shapes of thrusts and related folds are interpreted as mostly primary features inherited from the geometry of the palaeomargin, represented by pre-orogenic faults, according to a context of inversion tectonics. [ABSTRACT FROM AUTHOR]

Analysis of patterns of coastal circulation and sediment dispersal is an essential step for the study of controlling factors influencing the long-term dynamics of coastal systems. Modern settings offer the possibility to monitor relevant parameters over relatively short time spans. However, geological examples complement this perspective by providing a time-averaged record where longer trends and stratigraphically significant processes can be evaluated. This study investigates the shallow marine deposits of Le Castella terrace (Upper Pleistocene, southern Italy) to document how patterns of circulation influenced by coastline configuration can affect the preserved millennial-scale depositional record of a progradational shoreline system. The regressive portion of the Le Castella terrace deposits, developed during a relative sea-level highstand and falling stage, consists of a progradational wedge mainly composed of redistributed skeletal particles of a coeval shallow water carbonate factory. Preservation of the morphology of the paleocoastline and abundant current-related sedimentary structures allow reconstruction of the predominant sediment dispersal dynamics responsible for the formation of this sedimentary wedge. Facies and paleocurrent analysis indicate offshore and alongshore sediment transport modes, consistent with coastal circulation driven by storms normally incident to the shoreline and a sharp change in coastline orientation. This coastal inflection influenced circulation patterns causing flow separation and eddy formation in the lee of the curved coastline. Syndepositional tectonic deformation also affected the architecture of the preserved deposits, controlling the nucleation and development of a clinostratified body and determining localized lateral stratigraphic variability. This study illustrates how transient but recurrent circulation patterns associated with changes in coastal orientation and related to high-energy storm events can leave a predominant signature in the stratigraphic record of microtidal shallow-marine successions. [ABSTRACT FROM AUTHOR]

Combined stratigraphic and bio-magnetostratigraphic analyses on a fluvial sequence from the southern margin of the Alessandria Basin (at the junction between the Alps and the Apennines) provide evidence for the first documentation of a late Piacenzian-Gelasian continental record in northern Italy. The basin experienced general growth at the margins and ongoing subsidence in the depocentre, during overthrusting onto the Po Foreland Basin. The studied fluvial succession is 25-30 m thick and can be divided into three units (MRZ1, MRZ2 and MRZ3) delimited by erosional unconformities (S1, S2 and S3). The MRZ1 and MRZ2 units (shallow to confined braided systems) are chronologically restricted between 2.8 and 2.58 Ma based on bio-magnetostratigraphic analyses. The overall stratigraphic framework indicates deposition and erosion during the progressive uplift of the Alps/Apennines system. The frequency of unconformities and sedimentary changes, compared to other coeval successions of other syn-orogenic basins of northern and central Italy, suggests the interaction between high-amplitude global cold stages and tectonic deformation. Tectonic climax occurred in the Gelasian, as revealed by the 450- to 600-ka-long hiatus associated with the S3 unconformity, whereas the subsequent deposition of the MRZ3 unit (meandering alluvial system) including a Gelasian magnetic reversal points to the fading of tectonic activity. The stratigraphic reconstruction provided in this study enriches the current knowledge of the European continental biota: the absence of thermophilous elements in the MRZ1 carpoflora reflects the late Piacenzian cooling phase after 2.8 Ma, whereas the persistence of several extra-European taxa in MRZ3 (e.g. Ampelopsis cf. ludwigii, Boehmeria lithuanica, Cryptomeria rhenana) rules out an age younger than 1.4 Ma. The freshwater mollusc assemblage of MRZ2 shows the occurrence of Pomatias elegans and Tournouerina belnensis, identified for the first time in the Pliocene of northern Italy. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The 1928 CE volcanic activity on eastern Etna, Italy, produced wide surface deformation and high effusion rates along fissures, with excess volumes of about 50 million m3 of lavas. This, in conjunction with the low elevation of the main eruptive vents (1150 m a.s.l.), caused the destruction of the Mascali town. Our research focuses on a multidisciplinary study from field observations and Finite Element Method modelling through COMSOL Multiphysics®, with the aim of reconstructing the geometry, kinematics and origin of the system of faults and fissures formed during the 1928 event. We collected quantitative measurements from 438 sites of azimuth values, opening direction and aperture amount of dry fissures, and attitude and vertical offsets of faults. From west to east, four volcanotectonic settings have been identified, related to dike propagation in the same direction: 1) a sequence of 8 eruptive vents, surrounded by a 385-m wide graben, 2) a 2.5-km long single eruptive fissure, 3) a half-graben as wide as 74 m and a symmetric, 39-m-wide graben without evidence of eruption, 4) alignment of lower vents along the pre-existing Ripe della Naca faults. Field data, along with historical aerial photos, became inputs to FEM numerical models. The latter allowed us to investigate the connection between diking and surface deformation during the 1928 event, subject to a range of overpressure values (1–20 MPa), host rock properties (1–30 GPa) and geometrical complexity (stratigraphic sequence, layer thickness). In addition, we studied the distribution of tensile and shear stresses above the dike tip and gained insights into dike-induced graben scenarios. Our multidisciplinary study reports that soft (e.g. tuff) layers can act as temporary stress barriers and control the surface deformation scenarios (dike-induced graben, single fracture or eruptive fissures) above a propagating dike by suppressing the distribution of shear stresses towards the surface. • The 1928 eruption of Etna produced 14-km-long surface deformations of different types. • Field structural surveys at 438 sites and FEM modelling have been carried out. • We reconstructed the geometry, kinematics and origin of the fault and fissure system. • Soft layers act as temporary stress barriers controlling dyke-induced deformations. [ABSTRACT FROM AUTHOR]

By relocation of shallow and intermediate depth earthquakes and joint evaluation of already available and properly estimated waveform inversion focal mechanisms we investigate the location and shallow kinematics of the residual subducting slab in the Calabrian Arc region, that is the only, apparently still active segment of the old subduction front of the western Mediterranean. In agreement with high P-wave velocity anomaly found at intermediate depths by previous local earthquake tomography, our shallow-to-intermediate earthquake hypocentre distribution shows that the Ionian subducting slab is still in-depth continuous only in a small internal segment of the Arc, while detachment or break-off processes have already developed elsewhere along the Arc. At the same time, the space distribution and the waveform inversion focal mechanisms of the earthquakes occurring at shallow depth (<70 km) do not evidence Subduction Transform Edge Propagator (STEP) fault activity at the edges of the descending slab. In particular, no trace is found of dip-slip faulting along near vertical planes parallel to the slab edges, that is no seismic evidence is available of vertical motion between the subducting segment of the plate and the adjacent portion of it. Also, the seismicity distribution and mechanisms found at crustal depths in the study region do not match properly with the expected scenario of relative motion at the lateral borders of the overriding plate. Our earthquake locations and mechanisms together with GPS information taken from the literature highlight a residual, laterally very short subducting slab showing quasi-nil velocity of trench retreat and no present-day STEP activity, still capable however of causing strong normal-faulting earthquakes in the trench area through its gravity-induced shallow deformation in a weak-coupling scenario. [ABSTRACT FROM AUTHOR]

We present the results of an electric resistivity tomography (ERT) survey, combined with mappings of diffuse carbon dioxide flux, ground temperature and self-potential (SP) at Solfatara, the most active crater of Phlegrean Fields. Solfatara is characterized by an intense carbon dioxide degassing, fumarole activity, and ground deformation. This ensemble of methods is applied to image the hydrothermal system of Solfatara, to understand the geometry of the fluid circulation, and to define the extension of the hydrothermal plume at a high enough resolution for a quantitative modeling. ERT inversion results show Solfatara as a globally conductive structure, with resistivity in the range 1-200 Ω m. Broad negative anomaly of self-potential in the inner part of Solfatara with a minimum in the area of Bocca Grande suggests a significant downward flow of condensing liquid water. Comparison between spatial variations of resistivity and gas flux indicates that resistivity changes at depth are related to gas saturation and fluid temperature. These variations delineate two plume structures: a liquid-dominated conductive plume below Fangaia mud-pool and a gas-dominated plume below Bocca Grande fumarole. The geometry of the Fangaia liquid-saturated plume is also imaged by a high resolution 3-D resistivity model. In order to estimate the permeability, we propose a 2-D axis-symmetric numerical model coupling Richards equation for fluid flow in conditions of partial saturation with the resistivity calculation as function of saturation only. Alternatively, we apply the Dupuit equation to estimate the permeability of the shallow layer. Using these two approaches we obtain the permeability of the shallow layer below Fangaia which ranges between (2-4) x 10-14 m². [ABSTRACT FROM AUTHOR]

Abstract: A significant proportion of moderate-large earthquakes, plus aftershocks, nucleate within and propagate through upper-crustal carbonate-dominated sequences, where the effects of lithological variations on fault behaviour are poorly understood. The Gubbio fault is an active (1984, Ms=5.2) normal fault in Italy, hosted in Mesozoic–Cenozoic limestones and interbedded marls. Fault core domains derived from limestone at the studied outcrop are characterised by fractures/hydrofractures and breccias and host a number of localised (<1.5mm wide) principal slip zones (PSZs). The majority of displacement of up to 230m is concentrated in these PSZs, which comprise cataclasites, gouges, and calcite veins. Degassing bubbles, ‘quenched’ calcite, and the transformation of smectite to illite, are also observed within PSZs, implying frictional heating and seismic slip. In contrast, marl-rich domains exhibit distributed shear planes bounding a continuous and pervasive foliation, defined by phyllosilicate-rich pressure-solution seams. Microstructures in the seams include folds/kinks of phyllosilicates and pressure shadows around clasts, consistent with aseismic fault creep. A model is proposed for the behaviour of lithologically complex carbonate-hosted faults during the seismic cycle, whereby limestone-dominated fault core domains behave in a predominantly seismic manner, whereas phyllosilicate-rich domains behave in a predominantly aseismic manner. [Copyright &y& Elsevier]

We provide a step-by-step analysis and discussion of the 'PSI-based matrix approach', a methodology employing ground deformation velocities derived through Persistent Scatterer Interferometry (PSI) for the assessment of the state of activity and intensity of extremely to very slow landslides. Two matrices based on PSI data are designed respectively for landslides already mapped in preexisting inventories and for newly identified phenomena. Conversely, a unique intensity scale is proposed indiscriminately for both. Major influencing factors of the approach are brought to light by the application in the 14 km area of Verbicaro, in Northern Calabria (Italy). These include lack of PSI data within the landslide boundaries, temporal coverage of the available estimates, and need of field checks as well as the operative procedures to set the activity and intensity thresholds. For the area of Verbicaro, we exploit 1992-2011 PSI data from ERS1/2 and RADARSAT1/2 satellites, projecting them along the maximum slope directions. An activity threshold of ±5 mm/year is determined by applying the average projection factor of local slopes to the PSI data precision. The intensity threshold between extremely and very slow phenomena (16 mm/year) is reduced by ~20 % to account for temporal and spatial averages being applied to attribute representative velocities to each landslide. The methodology allows assessing the state of activity and the intensity for 13 of the 24 landslides premapped in the 2007 inventory and for two newly identified phenomena. Current limitations due to characteristics and spatial coverage of PSI data are critically tackled within the discussion, jointly with respective implications. [ABSTRACT FROM AUTHOR]

Abstract: Three main sets of deformation bands are identified in the Lower Pleistocene carbonate grainstones of Favignana Island (Italy). A bedding-parallel set is interpreted to contain compaction bands, based on the lack of evidence for shear. The other two sets are oriented at a high-angle to bedding, forming a conjugate pair comprised of compactive strike-slip shear bands. In this study, we focus on the compactive shear bands documenting their development, as well as analyzing their dimensional parameters and scaling relationships. Single compactive shear bands are thin, tabular zones with porosity less than the surrounding host rocks, and have thicknesses and displacements on the order of a few mm. The growth process for these structures involves localizing further deformation within zones of closely-spaced compactive shear bands and, possibly, along continuous slip surfaces within fault rocks overprinting older zones of bands. During growth, single bands, zones of bands and faults can interact and link, producing larger structures. The transitions from one growth step to another, which are controlled by changes in the deformation behavior (i.e. banding vs. faulting), are recorded by different values of the dimensional parameters for the structures (i.e. length, thickness and displacement). These transitions are also reflected by the ratios and distributions of the dimensional parameters. Considering the lesser porosity values of the structures with respect to the host rock, the results of this contribution could be helpful for mapping, assessing, and simulating carbonate grainstone reservoirs with similar structures. [Copyright &y& Elsevier]

Abstract: The characteristics of a shallow-level shear zone that is representative of the deformation in the external sectors of the Northern Apennine fold-and-thrust belt are described. The characterization involved an integrated approach using microstructural analysis of deformation fabrics, vitrinite reflectance measurements, XRD analysis on clay minerals and carbon and oxygen stable isotopes analyses. This data set provides the evidence that the thrust was active at very shallow depths (ca. less than 3 km), with maximum paleotemperatures ranging from 60° to 100–110 °C. The regime during fault activity evolved through cycles of compaction and dilation linked to transient build up of fluid overpressure and injection. The alternating cycles of fluids supply generated a fault-fracture mesh with a complex network of blocky and striped veins that formed at temperatures ranging from 150° to 200 °C, not compatible with the conditions in the host rocks. This evidence implies that the shear zone was flooded by hot fluids coming upward from diagenetic and low-grade metamorphic dehydration of clay minerals active at deeper structural levels. The fluids were thus highly channelled and focused where deformation also focused, producing a local pronounced isotopic difference between fluids and host rock. [Copyright &y& Elsevier]

Abstract: Surface deformations in L’Aquila (centre of Italy) caused by the April 6th, 2009 earthquake were studied from space geodesy and remote sensing points of view using Synthetic Aperture Radar Interferometry (InSAR) and Sub-pixel Correlation Technique (SCT). InSAR was used to measure ground surface deformation in the satellite line of sight (LOS) direction and the deformation was determined using two separate interferometric pairs of ENVISAT ASAR and ALOS PALSAR data sets. Furthermore, SCT was employed to investigate the horizontal displacements in the area. Two separate pairs of ENVISAT ASAR and ASTER optical image data sets were employed, and horizontal displacements in Range/Azimuth and in west–east/south–north directions were investigated, respectively. Maximum 28.1cm subsidence in LOS direction was observed on the descending interferogram of the ENVISAT ASAR data set, to the north-west of Onna village. The initial coseismic surface deformation started from the north of the main event epicentre. Most of the post-seismic relaxation occurred after April 7th, toward the south and south-east of the main shock epicentre, and results from SCT showed that the horizontal displacement was not significant on the surface (not more than a few centimetres). [Copyright &y& Elsevier]

The article examines the influence of antiformal settings on the evolution of alpine slopes using 2D numerical modelling. The northern slope of the Upper Vizze Valley, which follows a huge antiform involving meta-granitic and meta-sedimentary rocks, is affected by a complex gravitational phenomenon mainly controlled by the attitude of the foliation. A preliminary geological model based on field surveys was refined using the results of 2D distinct element numerical modelling. In the crown area, the sub-horizontal meta-sedimentary sequence at the fold hinge is cut by sharp planes, whilst in the middle zone the sequence was passively dragged downwards and finally, in the lowest part of the slope, corresponding to the steeply dipping antiformal flank, the deformation propagated across the entire meta-sedimentary succession through strain partitioning along multiple shear surfaces. [ABSTRACT FROM AUTHOR]

Abstract: The Lower Permian succession of the Central Southern Alps (Lombardy, Northern Italy) was deposited in fault-controlled continental basins, probably related to transtensional tectonics. We focussed our study on the stratigraphic record of the Lower Permian Orobic Basin, which consists of a 1000m thick succession of prevailing continental clastics with intercalations of ignimbritic flows and tuffs (Pizzo del Diavolo Formation, PDV) resting on the underlying prevailing pyroclastic flows of the Cabianca Volcanite. The PDV consists of a lower part (composed of conglomerates passing laterally to sandstones and distally to silt and shales), a middle part (pelitic, with carbonates) and an upper part (alternating sandstone, silt and volcanic flows). Syndepositional tectonics during the deposition of the PDV is recorded by facies distribution, thickness changes and by the presence of deformation and liquefaction structures interpreted as seismites. Deformation is recorded by both ductile structures (ball-and-pillow, plastic intrusion, disturbed lamination, convolute stratification and slumps) and brittle structures (sand dykes and autoclastic breccias). Both the sedimentological features and the geodynamic setting of the depositional basin confidently support the interpretation of the described deformation features as related to seismic shocks. The most significant seismically-induced deformation is represented by a slumped horizon (about 4m thick on average) which can be followed laterally for more than 5km. The slumped bed consists of playa-lake deposits (alternating pelites and microbial carbonates, associated with mud cracks and vertebrate tracks). The lateral continuity and the evidence of deposition on a very low-angle surface along with the deformation/liquefaction of the sediments suggest that the slump was triggered by a high-magnitude earthquake. The stratigraphic distribution of the seismites allows us to identify time intervals of intense seismic activity, which correspond to rapid and basin-wide changes in the stratigraphical architecture of the depositional basin and/or to the reprise of the volcanic activity. The nature of the structures and their distribution suggest that the magnitude of the earthquakes responsible for the observed structures was likely higher than 5 (in order to produce sediment liquefaction) and probably reached intensity as high as 7 or more. The basin architecture suggests that the foci of these earthquakes were located close to the fault-controlled borders of the basin or within the basin itself. [Copyright &y& Elsevier]

Abstract: Soft-sediment deformation structures are exposed in sea cliffs in the lower part of the Calcarenite di Gravina Formation (late Pliocene–early Pleistocene) in the Cala Corvino area N of Monopoli (Adriatic sector of the Apulian Foreland, southern Italy). Deformation affects a thickness of about 5m involving a lower calcareous–terrigenous sand and gravel unit and an upper heavily bioturbated grainstone and packstone unit. Deformation is absent from the overlying part of the succession. Large-scale soft-sediment deformation structures are collapse features comprising irregularly elongated conical zones of sinking. In vertical section, narrow “drop” zones occur in the lower sandy–gravelly facies and large gentle folds in the upper grainstone–packstone beds. The degree of deformation decreases upwards. Small-scale soft-sediment deformation structures adjacent to the large-scale conical collapse structures are narrow, vertically elongated load structures about 2m high and 30–50cm wide that involve only the basal terrigenous facies. The distribution of small- and large-scale soft-sediment deformation structures corresponds closely to zones of fracturing in the underlying Cretaceous limestones, and the elongation directions of soft-sediment deformation structures correspond to the orientation of major fractures in the limestones. The soft-sediment deformation occurred due to collapse associated with karstic sinkhole formation along fractures in the bedrock. Geometrical relationships between deformed and undeformed sedimentary units show that deformation occurred in a shallow marine environment. The structures at Cala Corvino provide a rare outcrop-scale record of sinkhole-induced soft-sediment deformation occurring in a shallow marine environment. [Copyright &y& Elsevier]

In the night of April 6, 2009, an earthquake of MW 6.3 magnitude occurred in the Abruzzo region. The hypocenter was estimated by the INGV at 42,35° N, 13,38° E, at a 9.5 km depth; moreover, at least one month of pre-seismic events preceded the main shock and aftershocks continued for at least 6 months. For the understanding of the geodetic and geodynamic implications of the earthquake, the temporal and spatial analyses of the phenomenon are fundamental; our research group has collected the GNSS data provided by about 50 permanent stations in the earthquake area and neighbouring regions; all the data have been processed in order to investigate the stations displacements and, if possible, the deformation pattern. In particular, the time series (two months of data both before and after the earthquake) of the daily coordinates were interpolated for each station in order to estimate the displacement at the main shock epoch: particular attention has been paid to carry out a proper covariance empirical estimation, in order to evaluate the displacement significance. Finally, the displacements of all the stations have been spatially analyzed to indentify the areas with similar displacements and the main discontinuities between them. Thirteen stations that significantly displace horizontally have been found: a rough clustering allows us to discriminate between a near field area that displaces mainly southwards, a south-western region that displaces in a SWdirection and a northeast region with an opposite motion. Only four station in the epicenter area significantly displace vertically, with drops between 3 and 12 cm. [ABSTRACT FROM AUTHOR]

Abstract: We report a laboratory and microstructural study of a suite of deformation experiments in which basalt from Mount Etna volcano is deformed and fractured at an effective confining pressure representative of conditions under a volcanic edifice (40MPa). Particular attention was paid to the formation of a fracture and damage zone with which to stimulate coupled hydro-mechanical interactions that create the various types of seismicity recorded on volcanic edifices, and which usually precede eruption. Location of AE events through time shows the formation of a fault plane during which waveforms exhibit the typical high frequency characteristics of volcano-tectonic (VT) earthquakes. We found that these VT earthquakes were particularly pronounced when generated using dry samples, compared to samples saturated with a pore fluid (water). VT events generated during deformation of water saturated sample are characterised by a distinctive high frequency onset and a longer, low frequency coda exhibiting properties often seen in the field as hybrid events. We present evidence that hybrid events are, in fact, the common type of volcanic seismic event with either VT or low frequency (LF) events representing end members, and whose proportion depend on pore fluid being present in the rock type being deformed, as well as how close the rock is to failure. We find a notable trend of reducing instances of hybrid events leading up to the failure stage in our experiments, suggesting that during this stage, the pore fluid present in the rock moves sufficiently quickly to provide a resonance, seen as a LF coda. Our data supports recent modeling and field studies that postulate that hybrid events generated in volcanic areas are likely to be generated through the interaction of hydrothermal fluids moving through a combination of pre-existing microcrack networks and larger faults, such as those we observe in forensic (post-test) examination. [ABSTRACT FROM AUTHOR]

The deformation pattern of the 6 and 7 April 2009 Mw=6.3 and Mw=5.6 earthquakes in L'Aquila is revealed by DInSAR analysis and compared with earthquake environmental effects. The DInSAR predicted fault surface ruptures coincide with localities where surface ruptures have been observed in the field, confirming that the ruptures observed near Paganica village are indeed primary. These ruptures are almost one order of magnitude lower than the ruptures that have been produced by other major surrounding faults in the past. These faults have not been activated during the 2009 event, but have the capacity to generate significantly stronger events. DInSAR analysis shows that 66% (or 305 km2) of the area deformed has been subsided whereas the remaining 34% (or 155 km2) has been uplifted. A foot-wall uplift versus hangingwall subsidence ratio of about 1/3 is extracted from the mainshock. The maximum subsidence (25 cm) was recorded about 4.5 km away from the primary surface ruptures and about 9 km away from the epicentre. In the immediate hangingwall, subsidence did not exceeded 15cm, showing that the maximum subsidence is not recorded near the ruptured fault trace, but closer to the hangingwall centre. The deformation pattern is asymmetrical expanding significantly towards the southeast. A part of this asymmetry can be attributed to the contribution of the 7 April event in the deformation field. [ABSTRACT FROM AUTHOR]

In the Southern Alps and the northern Dinarides the main Variscan deformation event occurred during Late Carboniferous (Bashkirian to Moscovian) time. It is represented locally by an angular unconformitiy, the "Variscan discordance", separating the pre-Variscan basement from the post-Variscan (Moscovian to Cenozoic) sedimentary cover. The main aim of the present contribution is to investigate whether a Variscan thermal overprint can be detected and distinguished from an Alpine thermal overprint due to Permo-Mesozoic basin subsidence in the Alpine-Dinaric Transition Zone in Slovenia. Vitrinite reflectance (VR) is used as a temperature sensitive parameter to determine the thermal overprint of pre- and post-Variscan sedimentary succeßions in the eastern part of the Southern Alps (Carnic Alps, South Karawanken Range, Paški Kozjak, Konjiška Gora) and in the northern Dinarides (Sava Folds, Trnovo Nappe). Neither in the eastern part of the Southern Alps, nor in the northern Dinarides a break in coalification can be recognized acroß the "Variscan discordance". Consequently the post-Variscan thermal overprint during Permo-Mesozoic paßive continental margin evolution and/or Cenozoic Alpine orogeny reached at least the same intensity as the Variscan (Late Carboniferous) one. In the northern Dinarides (Sava Folds, Trnovo Nappe) Triaßic and Cretaceous rocks reached a similar thermal maturity as the pre-Variscan ones. Therefore in these regions the Alpidic thermal overprint exceeded the Variscan one. The Alpidic thermal overprint in the northern Dinarides (Sava Folds, Trnovo Nappe) occurred in post-Late Cretaceous and pre-Mid Oligocene times. This is testified by a substantial gap in thermal maturity acroß the Upper Cretaceous - Middle Oligocene unconformity. Nappe stacking in the northern Dinarides had no impact on regional maturity patterns. Thermal maturity of post-Variscan Permo-Carboniferous rocks of the northern Dinarides is generally higher than in the South Karawanken Range and the Carnic Alps. This is a result of both, a deeper burial during Permo-Mesozoic basin subsidence and an accumulation of thick Paleogene flysch sediments during the Paleocene to Eocene Dinaric orogeny, [ABSTRACT FROM AUTHOR]

We investigate the 1992–2000 surface deformation affecting the Abruzzi region, Central Italy, by exploiting two set of Synthetic Aperture Radar (SAR) data, acquired by the ERS-1/2 SAR sensors from ascending and descending orbits, respectively. We apply the Small BAseline Subset (SBAS) Differential Synthetic Aperture Radar Interferometry (DInSAR) technique to the SAR data set to estimate the displacement time-series and the corresponding velocity maps. Our DInSAR analysis allows us to detect a previously unreported major change in crustal deformation moving from the highest elevation of the Central Apennines to the Adriatic sector, that we infer as evidence of a complex tectonic boundary between two Adriatic microplates involving a wide interaction zone. An extension effect, at a rate of about 0.10 × 10–6 yr−1, is also confirmed by our investigation. Our findings may have important implications in the seismic hazard assessment within the Adriatic region in Central Italy. [ABSTRACT FROM AUTHOR]

Elastic finite element models are applied to investigate the effects of topography and medium heterogeneities on the surface deformation and the gravity field produced by volcanic pressure sources. Changes in the gravity field cannot be interpreted only in terms of gain of mass disregarding the ground deformation of the rocks surrounding the source. Contributions to gravity changes depend also on surface and subsurface mass redistribution driven by dilation of the volcanic source. Both ground deformation and gravity changes were firstly evaluated by solving a coupled axisymmetric problem to estimate the effects of topography and medium heterogeneities. Numerical results show significant discrepancies in the ground deformation and gravity field compared to those predicted by analytical solutions, which disregard topography, elastic heterogeneities and density subsurface structures. With this in mind, we reviewed the expected gravity changes accompanying the 1993–1997 inflation phase on Mt Etna by setting up a fully 3-D finite element model in which we used the real topography, to include the geometry, and seismic tomography, to infer the crustal heterogeneities. The inflation phase was clearly detected by different geodetic techniques (EDM, GPS, SAR and levelling data) that showed a uniform expansion of the overall volcano edifice. When the gravity data are integrated with ground deformation data and a coupled FEM modelling was solved, a mass intrusion could have occurred at depth to justify both ground deformation and gravity observations. [ABSTRACT FROM AUTHOR]

Abstract: The present work concerns some observations about the paper by , related to the surface deformation analysis carried out for the earthquake that hit the city of L’Aquila, Italy, on April 2009 and based on SAR Differential Interferometry (DInSAR) technique. We have manly identified a criticality about the post-seismic deformation, named by the author postseismic relaxation. The analysis performed by leads to misleading conclusions in terms of seismic hazard all over the epicentral region. Here, some considerations driven by literature and interferograms comparison demonstrate the incorrectness of their interpretation concerning the coseismic and post seismic surface deformation. [Copyright &y& Elsevier]

The Quaternary Fucino basin in the central Apennines of Italy was struck by one of the strongest Italian earthquakes of the last millennium (1915, Mw 7.0). The Avezzano town, ~ 9.0 km away from the epicentre, was completely destroyed. In the surrounding area sizable coseismic surface deformation were catalogued, attesting the severity of earthquake, the proximity to the causative fault and the geological and geomorphological complexity of a basin filled by thick lacustrine sediments. The Avezzano area provides a case study to understand how shallow subsurface geology influences site effects in a deep Quaternary continental basin environment, thus being of potential interest for similar geologic contexts worldwide. Within the investigated area, different possible earthquake-induced effects can occur, such as a) stratigraphic amplifications in a wide range of resonance frequencies (from 0.4 to 15–20 Hz); b) liquefaction; c) coseismic surface faulting; d) basin-edge effects; and e) slope instability. We present and discuss results of basic seismic microzonation study (SM) of the Avezzano area, focusing on geologic constraints aimed at the reconstruction of the shallow subsurface geology, and associated potential for local seismic hazard. We adopted an interdisciplinary approach based on detailed geological-structural, geophysical and seismic analyses to investigate the seismic response of high-seismic risk area, such as the Avezzano town, given the urban and industrial expansion since the last century. We discuss methodological approaches and their uncertainties. • We reconstruct the geological-resonant model of the Avezzano town with detailed geological, subsurface and geophysical data; • The largest earthquake-induced effects are expected along the basin edge where sharp lithotecnical and elastic contrast occur; • Buried fault scarps and lens-shaped sedimentary bodies represent geometric-complexity in the geological model. [ABSTRACT FROM AUTHOR]

The objective of this study is to explain the occurrence and paleo-stress significance of 3D joint clustering in chert nodules (inclusions) within a layered pelagic limestone sequence. The difference in stiffness between chert and limestone is about one order of magnitude. Field observations show that fracture localization occurs mostly in chert nodules as opposed to the limestone matrix. We show with a novel three-dimensional geomechanical modelling analysis how the inclusion (ellipsoid) axes ratio influences fracture intensity and propagation within and outside the chert nodules and how the nodules record different deformation phases under different remote stress conditions. From field observations, we recognize two joint sets in the chert nodules: joints parallel and normal to the plane containing the two major axes of the nodule (bedding plane). In the nodules, the normal-to-bedding joints are interpreted to be younger than the parallel-to-bedding ones. The modelling of the 3D Eshelby solution for the stress field inside the chert nodule and in the surrounding matrix is consistent with our field observations and it suggests a strong differential stress during deformation (σ min r /σ max r < 0.3). Chert nodules in a deformed carbonate sequence, therefore, can provide important clues on the paleo-stress conditions, the temporal sequence of events, and fracture distribution heterogeneity. Image 1 • Chert nodules fracture mechanics in carbonates is modeled for the first time in 3D. • Eshelby's inclusion model applied to chert nodules explains field observations. • 3D nodule shape influences fracture intensity & propagation in nodule and host rock. • Fractures associated to chert nodules can be used as paleostress indicators. • Chert nodules mechanics explains joints distribution at Monte Conero, Italy. [ABSTRACT FROM AUTHOR]

During the last 20 years (1997 to 2017), four seismic sequences with Mw ≥ 5.5 mainshocks nucleated along the Central and Northern Apennines chain (Italy), causing casualties and damage: the 1997 Colfiorito, the 2009 L'Aquila, the 2012 Emilia, and the most recent 2016–2017 Central Italy seismic sequences. In this work, we perform a novel joint analysis of seismological and remote-sensing data to achieve new insights into the faulting process evolution during the considered seismic sequences. To this aim, we study these seismic sequences by exploiting the available seismological data and by applying fractals theory to them. In particular, we characterize the different behavior of compressional and extensional seismic sequences by examining the temporal evolution of the fractal dimension values. In addition, we compare the Differential Synthetic Aperture Radar Interferometry (DInSAR) displacement maps relevant to the considered seismic events (already published in our past papers) and the performed spatial and temporal seismological analyses, in order to emphasize some significant aspects of the different faulting processes active during these Italian seismic sequences. The analysis of the fractal dimension values shows that over time extensional seismic sequences are spatially distributed within a volume, whereas compressional ones are aligned along a preferential surface. These spatio-temporal patterns are confirmed by: (1) the spatial distribution of hypocenters for the events that occurred between the mainshock and the post-seismic synthetic aperture radar (SAR) acquisition; (2) the spatial extension of coseismic DInSAR ground-deformation patterns. The proposed seismic and ground-deformation analyses can thus typify different geodynamic contexts in Italy, providing a distinct image of articulated faulting processes. [ABSTRACT FROM AUTHOR]

A multiscale geometrical and kinematic characterization of fault zones is the starting point to understand fault mechanics, in particular that of potentially seismogenic faults. Fieldwork and seismological studies can provide pictures and kinematic characterization of faults at sub-regional scale (i.e., tens of kilometers). Until the advent of Digital Outcrop Models (DOMs), fieldwork was the sole source of information about the outcrop-scale (i.e., hundreds of metres) internal structure.Here, adopting the above-mentioned methodologies, we discuss the outcrop-scale geometrical and kinematic features of a seismogenic carbonate-hosted normal fault: the Tre Monti fault in Central Italy. In this area, NE-SW oriented extension is accommodated mainly by NW-SE faults, however rare ENE-WSW oriented faults, such as the Tre Monti fault, are also present. This fault crops out for ~7 km with a series of SSE dipping right stepping fault scarps. It accommodates ~1 km throw through a series of sub-parallel fault strands, and mostly shows dip-slip slickenlines. The outcrop-scale structure is well-exposed within an abandoned quarry and it is located between two right stepping fault segments.The integration of classical fieldwork with manual interpretation of a laser-scanner derived DOM allowed us to build a very detailed map and a cross-section displaying minor fault distribution in the fault damage zone. In addition, we calculated the normalised slip tendency and the slickenlines compatibility of the minor faults under three stress fields: (1) a NE-SW extension (regional stress field), (2) a sub-regional NW-SE extension obtained from the kinematic inversion of the slickenlines collected on the Tre Monti fault (fault stress field), and (3) a right lateral transtension/transcurrent deformation defined by the slickenlines collected on the main fault in the quarry (local stress field).Minor faults are heterogeneously distributed within the damage zone and are arranged in two main sets, (1) sub-parallel and (2) orthogonal to the main fault. The first set has the highest slip tendency values for the fault stress field, i.e. the geometry of the fault planes is optimally oriented within this stress field, but the slickenlines are more compatible with the local and regional stress fields. The geometry and kinematics of the second set are well-explained within the local stress field.The overall structure of the Tre Monti fault zone at the outcrop-scale mimics the fault structure at the sub-regional scale and resembles the architecture of seismogenic normal faults obtained from high-precision relocated aftershocks occurred during seismic sequences. We propose that the complexity in minor fault orientation and kinematics is caused by the interaction between the two right stepping fault segments that border the outcrop. [ABSTRACT FROM AUTHOR]

Monitoring surface deformation on dams is commonly carried out by in situ geodetic surveying, which is time consuming and characterized by some limitations in space coverage and frequency. More recently microwave satellite-based technologies, such as advanced-DInSAR (Differential Synthetic Aperture Radar Interferometry), have allowed the integration and improvement of the observation capabilities of ground-based methods thanks to their effectiveness in collecting displacement measurements on many non-destructive control points, corresponding to radar reflecting targets. The availability of such a large number of points of measurement, which are distributed along the whole structure and are characterized by millimetric accuracy on displacement rates, can be profitably adopted for the calibration of numerical models. These models are implemented to simulate the structural behaviour of a dam under conditions of stress thus improving the ability to maintain safety standards. In this work, after having analysed how advanced DInSAR can effectively enhance the results from traditional monitoring systems that provide comparable accuracy measurements on a limited number of points, an FEM model of the Genzano di Lucania earth dam is developed and calibrated. This work is concentrated on the advanced DInSAR technique referred to as Small BAseline Subset (SBAS) approach, benefiting from its capability to generate deformation time series at full spatial resolution and from multi-sensor SAR data, to measure the vertical consolidation displacement of the Genzano di Lucania earth dam. [ABSTRACT FROM AUTHOR]

Abstract: This paper is a response to the comments raised by Marco et al. referring to the work of on “Surface deformation caused by the April 6th 2009 earthquake in L’Aquila (Italy): A comparative analysis from ENVISAT ASAR, ALOS PALSAR and ASTER”. While some of the issues raised by them are relevant and appropriate, the authors believe that some of their comments arose from misunderstanding and needs some elaboration. In this paper, we address their comments and clarify the ambiguities. [Copyright &y& Elsevier]