Papers by Giorgio De Guidi
The discovery of submerged structures, in 2008, during archaeological works in the port of Lipari... more The discovery of submerged structures, in 2008, during archaeological works in the port of Lipari highlights a series of natural and anthropological factors on the struggle of the inhabitants of Lipari against the sinking of their old wharf. The actual excavations (2008The actual excavations ( -2013 radically changed the image of romantic coves with beaches for hauling boats in favor of a mighty structure connected to the port, also suggesting a review of the urban part of the Roman city: Lipari, for centuries a strategic center for the dominion of the southern part of the Tyrrhenian Sea, began to loose its importance, probably because of the sinking of the port, started around the 2 nd -1 st centuries BC and definitely canceled in the 3 rd -4 th century AD. The markers of this vertical deformation are remnants of Roman constructions, Middle Age buildings and morphological indicators of the sea level (i.e. marine notches, abrasion surfaces). Some among these indicators are time-constrained and provide an estimation of the rate of vertical displacement, while some others can only be considered as clues of submergence, but do not provide any velocities. Although the mechanism of the deformation is still unclear, we suggest, together with volcano related processes, the substantial incidence of regional tectonics. In particular, the activity of the NW-SE crustal-scale fault system affecting the whole volcanic arc and NE Sicily can account for the observed deformation.
<p>The geodynamic framework of Mount Etna volcano (Italy) is characterised by two s... more <p>The geodynamic framework of Mount Etna volcano (Italy) is characterised by two superimposed tectonic domains: a compressional one, oriented N-S, and an extensional one, oriented approximately WNW-ESE. The combination of these two domains and the volcano activity, has generated a complex system of faults prevalently on the eastern flank of the volcano. The eastern flank is the most active area of the volcano in terms of deformation and seismicity. The velocities there are at least one order of magnitude greater than in the rest of the volcano flanks due to the eastward sliding of the eastern flank.</p> <p>The monitoring and analysis of the acceleration occurring on the eastern flank of Mount Etna is the keystone to understand the volcano-tectonic dynamics that, apart from the tectonic and magmatic processes, involves the instability of this flank in a densely inhabited area.</p> <p>In order to monitor the deformation, Istituto Nazionale Geofisica e Vulcanologia – Osservatorio Etneo (INGV-OE) and the GeoDynamic & GeoMatic Laboratory of the University of Catania integrate GNSS and InSAR products with twofold objective: to characterize the dynamics of the area and to analyse the deformation transients, this last in view of a possible use in the framework of an alert system.</p> <p>Here, we analyse the ground deformation that occurred between 2016 and 2019 across the faults of the south-eastern flank of Mount Etna. On the south-eastern flank the deformation is accommodated by several faults which have different kinematics and behaviours. We discriminate the deformation transient and the activity of the Belpasso-Ognina lineament, Tremestieri, Trecastagni, San Gregorio-Acitrezza, Linera, Nizzeti and Fiandaca faults. The latter generated the 26 December 2018 earthquake, two days after the eruption of 24 December, which induced a clear post seismic deformation, detected by GNSS and InSAR data. In particular, we discriminate the deformation occurred along the San Gregorio-Acitrezza fault, which is accommodated by the Nizzeti fault, and we analyse the post seismic deformation along the Linera fault. We analyse the Slow Slip Events (SSE) that are observed in the GNSS and InSAR time series in the vicinity of the Acitrezza fault and we quantify and discuss the tectonic origin of the Belpasso-Ognina lineament that we interpreted as a tear fault.</p>
Bollettino Della Societa Geologica Italiana, 2006
A stratigraphic and structural analysis of the northern border of the Hyblean Plateau (south-east... more A stratigraphic and structural analysis of the northern border of the Hyblean Plateau (south-eastern Sicily) has been carried out. This area is characterised by the outcropping of Lower Miocene-Quaternary volcanics and sediments (Schmincke et alii, 1997; Grasso et alii, 2004) and by a prominent WSW-ENE striking fault system (Ghisetti & Vezzani, 1980; Grasso et alii, 2000). From a morphological point of view, the study of the area has been supported by the analysis of four 3D-prospective projections obtained by draping a mosaic of aerial photo on DEM (Digital Elevation Model). Stratigraphic sections have been reconstructed in three key areas distributed from the east to the west of the northern margin of Hyblean Plateau, named respectively Monte Ranne-Monte Serravalle, Salto di Primavera-Filidonna and Palagonia-Poggio Forca, where new Quaternary structures have been recognized. Upper Pliocene and Pleistocene volcanism developed in a shallow marine and locally subaerial environment (S...
Quaternary International, 2019
New dating of rapid vertical deformation of Santa Tecla Fault (Mt. Etna volcano, Sicily) scarps b... more New dating of rapid vertical deformation of Santa Tecla Fault (Mt. Etna volcano, Sicily) scarps by Lichenometry method.
<p>Mount Etna is located on eastern Sicily on the border of the collision z... more <p>Mount Etna is located on eastern Sicily on the border of the collision zone between the Eurasia and Nubia plate. The regional geodynamic framework is characterized by two superimposed regional tectonic domains: a compressional one oriented N-S and an extensional one oriented approximately WNW-ESE. These two domains, together with the volcano-tectonic one, generated a tectonic system which is unique in the world. It exhibits a complex system of faults prevalently on the eastern flank of the volcano, which is the most complicated in terms of interaction between the tectonic, volcano and gravitational processes. The eastern flank of Mount Etna is the most active area of the volcano in terms of deformation and seismicity, because the deformation rates are at least one order of magnitude greater than the surrounding area, due to the eastwards sliding of this flank.</p><p>The monitoring and analysis of the high deformation occurring on the eastern flank of Mount Etna is the keystone for understanding the volcano-tectonic dynamics that, apart from the tectonic and volcanic processes, it is paramount relevant because involves the instability of this flank in a densely inhabited area. In this context the Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo (INGV-OE) created one of the most sophisticated and complete monitoring networks in the world in terms of number of multi-disciplinary station (seismic, geodetic, geochemistry). Since 2014, the GeoDynamic & GeoMatic Laboratory (GD&GM-LAB) of the University of Catania started to create many GNSS sub networks, belonging to the UNICT-Net, in order to determine the offsets occurring on the blocks of each fault of the eastern flank.</p><p>In order to have a complete analysis of deformation, INGV-OE and the GD&GM-LAB started to consider this area as an “open-air laboratory” where integrate GNSS and InSAR data with the twofold objective: to characterize the dynamic of this area for contributing to the volcanic hazard assessment and to identify precursor phenomena on shear structures analysing the relationship between kinematics, dynamics and volcano processes in the frame of the ATTEMPT INGV project.</p>
Italian Journal of Geosciences, 2010
In Sicily, the imbrication of the Apenninic thrust belt above the African foreland determined the... more In Sicily, the imbrication of the Apenninic thrust belt above the African foreland determined the progressive southward migration of marine basins that were shortened from the Middle Miocene until the Pleistocene. The area studied in detail is located in the Caltanissetta Basin, which was in fact, during Neogene times, a series of thrust-top basins (e.g. Corvillo and Mandre). The relationships between Neogene sedimentation and the synchronous development of fold and thrust structures are recorded by unconformities, lap relationships of strata, hiatuses. The stratigraphy of the substratum is dominated by varicoloured clays and siliciclastic deposits of Cretaceous-Early Miocene age. The thrust-top basin stratigraphy is represented by Tortonian siliciclastic deposits and evaporitic deposits, which are the product of the Messinian lowstand. The Early Pliocene flooding was responsible of deposition of chalks and marls and a later regional uplift produced a regression, during Late Pliocene times, with deposition of marls and sandstones. Compressional deformation acted continuously from Middle Miocene until, at least, Middle Pliocene, amplifying the pre-existing structures and creating differing styles of deformation depending on the lithologies involved.
Italian Journal of Geosciences, 2010
... Etna Quaternary substratum sediments, are constituted by the lava flows (350-250 ka; Gillotet... more ... Etna Quaternary substratum sediments, are constituted by the lava flows (350-250 ka; Gillotet alii, 1994) outcropping east of Paternò at the top of sands and conglomerates of the oldest terrace, and by the neck of Motta Sant'Anastasia, intruded in the same terraced deposits (see ...
Natural Hazards and Earth System Sciences, 2021
Annals of Geophysics, 2001
Nakamuras technique, or the H/V spectral ratio method, has been applied to microtremor measureme... more Nakamuras technique, or the H/V spectral ratio method, has been applied to microtremor measurements carried out in the urban area of Catania (Eastern Sicily) to obtain information on the geological structure of some sites,and to make a hypothesis on their seismic response. In general, sites located on soft soils or anthropic debris fillings have shown greater amplification at high frequencies (above 1 Hz). However, a strong lateral variation was observed in the frequency band, thus a denser grid of measurement points is necessary for a precise mapping of the resonant frequencies. In the low frequency range, between 0.1 and 1 Hz, a common peak around 0.2 Hz was observed. The fundamental resonant frequency inferred from the main peak in the H/V spectrum has been used to calculate the depth of the interface between the clays and the main reflector on the basis of the shear-wave velocity: it has been estimated as about 700 m.
Clean Technologies and Environmental Policy, 2016
This study is aimed at investigating the levels of polyaromatic hydrocarbons and nitro-polyaromat... more This study is aimed at investigating the levels of polyaromatic hydrocarbons and nitro-polyaromatic hydrocarbons in polluted urban soils and the potential application of microwave heating as decontamination treatment. The soil samples were collected from an area of 0.05 km 2 of Catania (Sicily, southern Italy) rural site. HPLC in fluorescence and electrochemical-fluorescence detection mode were used for selective separation, identification and quantification of pollutants in soil samples. A bench-scale microwave treatment was performed irradiating a contaminated soil using different operating powers for removing both kinds of contaminants. Results reveal that soil pollutant concentrations were sometimes higher than those found in other locations. Polyaromatic and nitropolyaromatic hydrocarbon levels observed suggest a strong contribution from incomplete combustion of gasoline or other fuels also due to the vicinity to the airport. Many polyaromatic hydrocarbon derivatives are more carcinogenic than the initial contaminant form and may have toxicological significance, even if present at much lower concentrations than their parent compounds. Thus, the environmental levels of these pollutants need to be monitored and removed. Contaminant removals from simulated microwave remediation show that the treatment is effective. Results also showed that contaminant features, especially polarity, significantly influence the dielectric properties of the soil and thus the final temperature reachable during the heating processes and the contaminant removals.
Rendiconti della Societa Geologica Italiana
ABSTRACT
Rendiconti Online Societa Geologica Italiana
Bollettino- Societa Geologica Italiana
In eastern Sicily, fold and thrust deformation affected Middle Pleistocene continental deposits b... more In eastern Sicily, fold and thrust deformation affected Middle Pleistocene continental deposits both at the front and in the axial zone of the Sicilian thrust belt. Along the southern slope of the axial zone, in the Nebrodi Mountains, fluvial terraces flanking the mountain sector of the Simeto River Valley are deformed by a NW-SE striking dextral strike-slip fault associated with a fold having vergence to the SSE. To the south, a Lower-Middle Pleistocene marine to continental succession, forming the sedimentary substratum of Mt. Etna volcano, is folded in a south-verging anticline. This structure, interpreted as a fault propagation fold at the front of the mountain belt, warped -240 kyr old conglomerates. Contractional processes have been followed by a huge entrenchment of rivers, which propagated from the Ionian coast inland, as consequence of the Late Quaternary high-rate of uplifting. This process has been recorded by the formation of severely displaced marine terraces along the Ionian coast. Uplift rates of 0.65 mm/yr since ∼400 kyr in the south-eastern coast, 1.3 mm/yr since -200 kyr in the Catania area and 1.4 mm/yr since 125 kyr in the north-eastern sector, have been estimated. In the thrust belt, the final uplift occurred at the end of the contractional regime (-200 kyr ago), marking a main change in the tectonic regime. The acceleration of the uplift processes, migrating from the foreland to the Mountain Belt with progressively higher rates, can be explained as the effect of the northward propagation of the normal faulting that, related to the regional WNW-ESE extensional tectonic regime of the Siculo-Calabrian rift, occurs in the Ionian offshore.
The volcanic areas experience the greatest deformation in term of velocity and spatiotemporal var... more The volcanic areas experience the greatest deformation in term of velocity and spatiotemporal variability. Cyclic episodes of short-term inflation and deflation, registered during eruptions, are related to magma chambers or dykes migration. Long-term deformations are ascribable to intrusion of large subvolcanic bodies into the crust or even to sub-crustal processes like the rise of a mantle plume. Unfortunately, is not always possible to discriminate among all these processes because they superimpose in space and in time. In this research, bringing the example of Mt. Etna volcano (Italy), we highlight the existence of a source of deformation not directly related to a volcanic process, but that is rather related to the nature of the crust hosting the volcanism. The occurrence of “anorogenic” volcanism such Mt. Etna in the collisional context of the Central- Mediterranean area can sometimes appear anomalous (Lustrino et al. 2011), and is a part of why the tectonic origin of volcanism ...
Uploads
Papers by Giorgio De Guidi