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Barberi, Graziella
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Barberi, Graziella
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graziella.barberi@ingv.it
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- PublicationOpen AccessSlab narrowing in the Central Mediterranean: the Calabro-Ionian subduction zone as imaged by high resolution seismic tomography(2018-03-26)
; ; ; ; ; ; ; ; ; ; ; A detailed 3D image of the Calabro-Ionian subduction system in the central Mediterranean was obtained by means of a seismic tomography, exploiting a large dataset of local earthquakes and computing algorithms able to build a dense grid of measure nodes. Results show that the slab is continuous below the southern sector of the Calabro-Peloritan Arc, but the deformation processes developing at its edges are leading to its progressive narrowing, influencing tectonics and magmatism at the surface, and with possible stress concentration in the tip zones. In the southwest, the deformation occurring at a free slab edge lead to propagation of a vertical lithospheric tear in the overriding plate, which extends along a NW-SE fault system (Aeolian-Tindari-Letojanni) up to about 30 km into the Ionian Sea; further southeast, the lithosphere appears only flexed and not broken yet. In the northeast, the slab seems to break progressively, parallel to the trench. Finally, northwest of Mt. Etna, the tomography highlights low VP that can be related to an upwelling of deep mantle material likely flowing laterally through a window opened by the complete slab detachment.674 16 - PublicationOpen AccessSismicità all’Etna tra Luglio 2005 e Gennaio 2006: evidenze di intrusione magmatica e di dinamica di fianco(2009-11-16)
; ; ; ; ; ; ;Cocina, O.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Giampiccolo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Milluzzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Musumeci, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; Nel presente lavoro sono presentati i risultati di uno studio della sismicità dell’Etna registrata tra Luglio 2005 e Gennaio 2006. Durante tale periodo l’integrazione dei dati provenienti da un esperimento condotto attraverso l’impiego di 20 stazioni temporanee a larga banda in aggiunta alla rete permanente, costituita da 40 stazioni, ha permesso di ottenere migliori localizzazioni ipocentrali (maggior numero di letture P ed S, riduzione degli errori ipocentrali e del gap azimutale). Ciò ha consentito analisi di maggior dettaglio anche degli eventi a più bassa magnitudo (M<2.0) che costituiscono il 75 % del campione. In particolare, si è proceduto alla rilocalizzazione degli eventi (Fig. 1) utilizzando il modello di velocità 3D di Patanè et al. (2006) e al calcolo dei meccanismi focali. La maggior parte della sismicità è localizzata sul fianco orientale del vulcano permettendo una più accurata interpretazione della dinamica di questo settore. Inoltre, la localizzazione 3D dei terremoti ha meglio evidenziato l’attività sismica lungo il Rift meridionale del vulcano relativa ad uno sciame profondo (tra 10 e 15 km) registrato nell’agosto del 2005, probabilmente correlata ad una intrusione magmatica. Infatti, tale sismicità è stata seguita nei mesi successivi da un forte incremento del tremore che, tuttavia, non ha portato nel breve termine ad alcuna eruzione. Ciò nonostante, è stato osservato che in altri periodi la sismicità lungo questo trend strutturale ha preceduto di alcuni mesi l’attività eruttiva (2001, 2002-2003 e 2008).115 76 - PublicationOpen AccessSeismic strain and seismogenic stress regimes in the crust of the southern Tyrrhenian region(2003-08-01)
; ; ; ; ;Neri, G.; Dipartimento di Scienze della Terra, Università di Messina, Italy ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Orecchio, B.; Dipartimento di Scienze della Terra, Università di Messina, Italy ;Mostaccio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ;An investigation has been performed to identify and characterize the seismic deformation zones active over the last decades in the region of Italy that has experienced the strongest seismicity during the last centuries. The study is based on the estimate of hypocenter locations, fault plane solutions, seismogenic stress and seismic strain tensor orientations carried out using the entire dataset of the national and local seismic networks, and the recently improved three-dimensional (3D) crustal velocity model of the study area. A series of simulation tests have been performed to evaluate the significance of the earthquake space distribution obtained and whether it was influenced by network geometry problems related to the sea and the lack of ocean bottom seismometers. In the sectors where hypocentral location was synthetically proved to be reliable, space distributions of earthquakes located with epicenter and focal depth errors less than 3 and 4 km, respectively, have been compared with local geology in order to identify seismogenic faults. The dataset of 32 fault plane solutions estimated with fault parameter errors less than 20° has been used to investigate space variations of seismogenic stress and seismic strain orientations over the study area. Stress was found to be uniform in the Messina Strait and southern Calabria where inversion of the available set of 11 fault plane solutions showed clear evidence of an extensional regime. The different orientations of the minimum compressive stress and strain found in this sector, together with the information available on local geology and tectonics, lead us to propose that the seismicity occurring over the last decades in the Messina Strait and southern Calabria was not in general produced at the main faults, but at minor faults activated by the main tectonic stress field acting in the area. To the west, in the sector including western Etna, the Nebrodi chain and the western Aeolian Islands, analysis of the available set of 16 fault plane solutions revealed a certain degree of stress heterogeneity with an apparent prevalence of north–south compression. This east to west change of stress–strain regimes is evaluated in the light of current hypotheses regarding the geodynamics of the study region.213 364 - PublicationOpen AccessFrequency-magnitude distribution of earthquakes at Etna volcano unravels critical stress changes along magma pathways(2022)
; ; ; ; ; ; ; ; ; ; ; The high seismic productivity of volcanic areas provides the chance to investigate the local stress conditions with great resolution, by analysing the slope of the frequency-magnitude distribution of earthquakes, namely the b-value. Here we investigated the seismicity of Mt. Etna between 2005 and 2019, focusing on one of the largest known episodes of unrest in December 2018, when most of the intruding magma aborted, rather oddly, its ascent inside the volcano. We found a possible stress concentration zone along magma pathways, which may have inhibited the occurrence of a larger eruption. If the origin of such hypothetical loaded region is related to tectonic forces, one must consider the possibility that geodynamic processes can locally result in such rapid crustal strain as to perturb the release of magma. Strong b-value time-variations occurred a few days before the unrest event, suggesting new possibilities for investigating the volcano state and impending eruptions.578 36 - PublicationOpen AccessThe EARTHCRUISERS project (EARTH CRUst Imagery for investigating SEismicity, volcanism and marine natural Resources in the Sicilian offshore)(2019-06-26)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The EARTHCRUISERS project was developed for the MIUR’s call “Progetti Premiali 2015” by the “Istituto Nazionale di Oceanografia e di Geofisica Sperimentale” (Trieste, Italy) in collaboration with the “Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo” (Catania, Italy) and “Stazione Zoologica Anton Dohrn” (Naples, Italy). The main goals of the project are: (i) to identify and characterize the main crustal tectonic structures offshore Sicily and the Aeolian Islands, (ii) to better understand the geodynamic processes controlling seismicity and volcanism affecting this region, and (iii) to furnish a useful tool to estimate seismic, tsunamigenic and volcanic hazard in the highly populated coastal sectors. Furthermore, in order to contribute at the Blue Growth objectives, the project aims to analyze some relevant issues related to mineral prospecting offshore, such as the characterization of the hydrothermal systems in the Tyrrhenian Sea and the impact of the exploitation of oil and gas fields on the marine environment in the Sicily Channel. To achieve these objectives the acquisition of multibeam and sidescan sonar, multichannel seismic reflection, magnetic and gravimetric data is planned. Nearly 2500 km of multichannel seismic reflection lines will be acquired during the project in the Marsili Basin (Tyrrhenian Sea) and Mt. Etna offshore. This large amount of data will allow to: better understand the relationship between tectonics and evolution of volcanism; identify active faults and volcanic bodies; better constrain the seismostratigraphic and structural setting of the study areas, and investigate the eventual occurrence of unstable volcanic slopes which could lead to landslide and tsunami. Finally, the deployment offshore southeastern Sicily of a temporary Ocean Bottom Seismometer (OBS) network will carry out for monitoring the natural seismicity in the area of VEGA platform, the largest oil extraction site in Italian seas. Data collected will be used to study the eventual correlation between local seismicity and oil extractive activities.144 37 - PublicationOpen AccessMultidisciplinary geophysical study of the NE sector of the unstable flank of Etna volcano(2015-04-12)
; ; ;Siniscalchi, A.; ; ;Romano, G.; ;Tripaldi, S. ;Bonforte, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cocina, O.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Siniscalchi, A.; Università degli Studi di Bari, Dipartimento di scienze della Terra e Geoambientali ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Guglielmino, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Romano, G.; Università degli Studi di Bari, Dipartimento di scienze della Terra e Geoambientali ;Sicali, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Tripaldi, S.; Università degli Studi di Bari, Dipartimento di scienze della Terra e Geoambientali; ; ;Università degli Studi di Bari, Dipartimento di scienze della Terra e Geoambientali; ; ;Università degli Studi di Bari, Dipartimento di scienze della Terra e Geoambientali; Università degli Studi di Bari, Dipartimento di scienze della Terra e GeoambientaliOn volcanic areas, usually characterized by complex structural environments, a lot of independent geophysical studies are usually performed. The non-uniqueness of the geophysical inverse models, the different level of reso- lution and sensitivity of the results spurred us to integrate independent geophysical datasets and results collected on Mt. Etna volcano, in order to obtain more accurate and reliable model interpretation. Mt. Etna volcano is located along the eastern coast of Sicily and it is characterized by a complex structural set- ting. In this region, the general N-S compressive regime related to the Africa – Europe collision interacts with the WNW-ESE extensional regime associated to the Malta Escarpment dynamics, observable along the eastern coast of Sicily. At Mt Etna, a great number of studies concerns the existence of instability phenomena; a general eastward mo- tion of the eastern flank of the volcano has been measured with always increasing detail and its relationship with the eruptive and magmatic activity is being investigated. The unstable flank appears bounded to the north by the E–W-trending Provenzana - Pernicana Fault System and to the SW by the NS Ragalna Fault system. Eastwards, this area is divided by several NW–SE trending faults. Recent studies consider this area as divided into several blocks characterized by different shape and kinematics. Ground deformation studies (GPS and InSAR) define the NE portion of the unstable flank as the most mobile one. In the frame of the MEDiterranean Supersites Volcanoes (MED-SUV) project, ground deformation data (GPS and INSAR), 3D seismicity, seismic tomography and two resistivity model profiles, have been analyzed together, in order to put some constraints on the deep structure of the NE sector of the unstable flank. Seismic data come from the permanent network run by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) - Sezione di Catania, Osservatorio Etneo. Ground deformation data comes from InSAR Permanent Scatterers analyses of different spaceborn sensors. The resistivity models come from a MT survey carried out on the eastern flank of the volcano and consisting of thirty broad-band soundings along N-S and NW-SE oriented profiles. We found that the NE sector of the sliding volume, modeled by ground deformation data inversions and character- ized by the highest displacement velocity, is characterized low resistivity values and it is bounded by two seismic clusters. The northern one is clearly related to the Pernicana fault and it’s not deeper than 3 km b.s.l. while the second one is located southwards, beneath the northern wall of the Valle del Bove, not related to any evident struc- ture at the surface. An evident layer with very reduced seismicity lies at 3 km of depth and well corresponds to the simplified analytic models of a sliding planar surface resulting from GPS data inversions.233 123 - PublicationOpen AccessSeismotomography of the crust in the transition zone between the southern Tyrrhenian and Sicilian tectonic domains(2002-12-13)
; ; ; ; ;Neri, G.; Dipartimento di Scienze della Terra, Messina University, Italy ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Orecchio, B.; Dipartimento di Scienze della Terra, Messina University, Italy ;Aloisi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ;A crustal tomography of seismic wave velocity was performed in the contact zone between the southern Tyrrhenian, Sicilian and Ionian tectonic units, a zone where the lithospheric structure can be expected to furnish evident signatures of dynamics related to the Tyrrhenian subduction process. A dataset of 10241 P and 5597 S readings from 932 local earthquakes recorded between 1978 and 2001 by stations operating in Sicily and Calabria was inverted by the SIMULPS12 algorithm for simultaneous computation of hypocenter parameters and Vp and Vp/Vs three dimensional distributions. The study brought significant improvement in the knowledge of the local velocity structure, furnishing new information useful to better identify the local tectonic units. The results appear to be compatible with the most recent hypotheses regarding the geodynamics of the study region.180 150 - PublicationOpen AccessTomographic images and analysis of stress and strain tensors at Mt. Etna: the magmatic unrest leading to the 2008 Etna eruption(2009-11-16)
; ; ; ; ; ; ;Alparone, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cocina, O.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Giampiccolo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Musumeci, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; We analysed the seismic activity preceding and accompanying the onset of the 2008 Mt. Etna eruption. Since January 2008, a clear seismic evidence of a magmatic unrest of the volcano was observed. Seismicity was firstly located in the southwestern sector of the volcano, at depth ranging between 10 and 20 km, along two tectonic structures (NE-SW and NNW-SSE) usually associated with deeper magmatic recharge mechanisms (Figs. 1, 2). Afterwards, the seismicity was located along the shallower portions of the main structures of the northeastern and southern flanks of the volcano (Figs. 1, 2). On May 13, 2008 an intense seismic swarm (about 230 events in 7 hours) announced the beginning of the eruption (Fig. 1, white circles). In order to provide seismological constraints to the magmatic unrest of the volcano, 336 earthquakes recorded from January 2007 to May 2008 (magnitude greater than 1.0) were selected for stress and strain tensors computation and 3D velocity and attenuation structure determination. This in order to individuate possible stress variations caused by the activation of magmatic sources which can be well evidenced by 3D tomographic images.139 441 - PublicationRestrictedIntrusive mechanism of the 2008–2009 Mt. Etna eruption: Constraints by tomographic images and stress tensor analysis(2012-04-11)
; ; ; ; ; ; ;Alparone, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cocina, O.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Giampiccolo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Musumeci, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; Since January 2008, several geophysical parameters have evidenced a recharging phase at Mt. Etna volcano culminating with an effusive eruption that began on May 13, 2008. Seismic activity recorded at Mt. Etna from January 2007 to May 2008 was analyzed in order to provide seismological constraints to the volcano dynamics leading to the eruption. A total of 336 selected earthquakes, withML≥1.5, were used as data source for this study. Specifically, we calculated 3D velocity and attenuation tomography, including a 3D relocation of the events, and we computed 53 selected fault plane solutions (FPSs) that were used for stress tensor inversion. The most important result obtained from the joint analysis of VP, VP/VS and P-wave attenuation is an anomalous zone with normal to high VP (values between 3.5 and 4.5 km/s) and low VP/VS (values≤1.64), which partially overlaps with a low QP (values≤50) volume located along a NS trending channel beneath the central crater. This can be interpreted as a shallow volume characterized by high temperature where the magma is located with the presence of supercritical fluids. The analysis of seismic stress tensor evidenced an extensional regime in the depth range 3–13 km with a vertically oriented σ1. This finding may suggest an extensional stress regime, probably related to the kinematic response of the volcanic edifice to both a deep magmatic intrusion and a condition of decreased regional compressive stress facilitated by sliding processes of the eastern flank of the volcano.648 38 - PublicationOpen AccessNew Geological, seismological and geodetic evidence of active thrusting and folding south of Mt. Etna (eastern Sicily): revaluation of “seismic efficiency” of the Sicilian Basal Thrust(Rendiconti Online della Società Geologica Italiana, 2014-09-01)
;De Guidi, G.; ;Barreca, G.; ;Cultrera, F. ;Grassi, S. ;Imposa, S. ;Mattia, M. ;Monaco, C.; ;Scudero, S. ;De Guidi, G.; Università Catania ;Barberi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Barreca, G.; Università Catania ;Bruno, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cultrera, F.; Università Catania ;Grassi, S.; Università Catania ;Imposa, S.; Università Catania ;Mattia, M.; Università Catania ;Monaco, C.; Università Catania ;Scarfì, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scudero, S.; Università Catania ;Università Catania; ;Università Catania; ;Università Catania ;Università Catania ;Università Catania ;Università Catania ;Università Catania; Università CataniaNew geological, seismological and geodetic data indicate that a NNW-SSE compressive regime occurs in the southern and western sector of Mt. Etna, accommodated by aseismic folding at the front of the chain. In particular, a large WSW-ENE trending anticline (the Catania anticline) is growing west and north of Catania within a middle-late Pleistocene fold system. For its location, geometry and growth rate, it is consistent with detachment fold models. We exclude that this structure have developed in response to volcanic spreading, as proposed by previous authors. Looking at the earthquakes distribution , an interesting finding is a clear trend of the seismic events deepening from very shallow hypocenters, in the area south of Etna, down to a depth of about 35 km, towards the NNW. Moreover, most of the events are clustered. We computed the focal mechanisms for the major and best recorded earthquakes occurring in the area. One cluster located at few kilometers north-west of the summit craters shows fault mechanisms of the deeper events with nearly horizontal P-axes striking NNW-SSE. A segment of the Sicilian Basal Thrust, located at crustal depth under the northwestern sector of the volcano, could be the seismic source. We propose the occurrence of detachment folding at the chain front, as response of a surface frontal propagation of this regional structure, migrating within the clayish middle-late Pleistocene foredeep deposits or at the top of the buried Hyblean foreland sequence. Geological and morphometric analyses suggest a maximum up warp deformation along the anticline axis of 40 m in the last 6000-7000 yrs, with a vertical slip-rate of 5 - 7 mm/yr. These values are consistent with the growth rate of 9 - 10 mm/yr estimated by interferometric data and the horizontal shortening of 5 mm/yr obtained by GPS measurements. Our analysis confirms that, besides the activity related to the volcanic feeding system, the seismic pattern under Mt. Etna edifice can be certainly related to the regional dynamics. The compressive stress is converted into elastic accumulation and then in earthquakes along the ramps to the rear of the chain, whereas along the frontal detachment it is accommodated by aseismic ductile deformation. In fact, despite the high rates of convergence, the seismicity is moderate at the front of the chain and the “seismic efficiency" of the Sicilian Basal Thrust is greater in correspondence of ramps at the rear, where strong earthquakes can occur.180 63