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Troiano A, Di Giuseppe MG, Isaia R. 3D structure of the Campi Flegrei caldera central sector reconstructed through short-period magnetotelluric imaging. Sci Rep 2022; 12:20802. [PMID: 36460790 PMCID: PMC9716173 DOI: 10.1038/s41598-022-24998-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022] Open
Abstract
The Campi Flegrei caldera experienced an unrest phase dating to 2005, which primary expression is the impressive ground uplift, accompanied by increasing degassing and seismic activities. Such last two phenomena developed mainly in the caldera central sector, including the Solfatara-Pisciarelli complex. However, the inner structure of such an area is still not defined, and this originates a poor understanding of the ongoing unrest. This paper describes the results of a new magnetotelluric survey performed in the Campi Flegrei caldera central sector. Through the inversion of data collected in 47 independent soundings, a 3D model of the electrical resistivity has been retrieved, which evidenced a partition of the investigated structure. The Agnano-Astroni area seems to be associated with a liquid-dominated geothermal reservoir, whereas the Solfatara-Pisciarelli area seems to be characterized by a single mixed liquid and gasses-dominated geothermal reservoir, which supplies the main caldera fumaroles. The proposed reconstruction of the geometrical characteristics of the hydrothermal system and the primary fluid rising pathways gives substantial clues about the significance of the detected structures in the evolution of the caldera unrest.
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Affiliation(s)
- A. Troiano
- grid.410348.a0000 0001 2300 5064Sezione di Napoli ‘Osservatorio Vesuviano’, Istituto Nazionale di Geofisica e Vulcanologia, Naples, Italy
| | - M. G. Di Giuseppe
- grid.410348.a0000 0001 2300 5064Sezione di Napoli ‘Osservatorio Vesuviano’, Istituto Nazionale di Geofisica e Vulcanologia, Naples, Italy
| | - R. Isaia
- grid.410348.a0000 0001 2300 5064Sezione di Napoli ‘Osservatorio Vesuviano’, Istituto Nazionale di Geofisica e Vulcanologia, Naples, Italy ,grid.5326.20000 0001 1940 4177Istituto di Geologia Ambientale e Geoingegneria, Consiglio Nazionale delle Ricerche, Roma, Italy
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Mineral-Melt Equilibria and Geothermobarometry of Campi Flegrei Magmas: Inferences for Magma Storage Conditions. MINERALS 2022. [DOI: 10.3390/min12030308] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The eruptions of Campi Flegrei (Southern Italy), one of the most studied and dangerous active volcanic areas of the world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte and phonotrachyte. Petrological investigations carried out in past decades on Campi Flegrei rocks provide crucial information for understanding differentiation processes in its magmatic system. However, the compositional features of rocks are a palimpsest of many processes acting over timescales of 100–104 years, including crystal entrapment from multiple reservoirs with different magmatic histories. In this work, olivine, clinopyroxene and feldspar crystals from volcanic rocks related to the entire period of Campi Flegrei’s volcanic activity are checked for equilibrium with combined and possibly more rigorous tests than those commonly used in previous works (e.g., Fe–Mg exchange between either olivine or clinopyroxene and melt), with the aim of obtaining more robust geothermobarometric estimations for the magmas these products represent. We applied several combinations of equilibrium tests and geothermometric and geobarometric methods to a suite of rocks and related minerals spanning the period from ~59 ka to 1538 A.D. and compared the obtained results with the inferred magma storage conditions estimated in previous works through different methods. This mineral-chemistry investigation suggests that two prevalent sets of T–P (temperature–pressure) conditions, here referred to as “magmatic environments”, characterized the magma storage over the entire period of Campi Flegrei activity investigated here. These magmatic environments are ascribable to either mafic or differentiated magmas, stationing in deep and shallow reservoirs, respectively, which interacted frequently, mostly during the last 12 ka of activity. In fact, open-system magmatic processes (mixing/mingling, crustal contamination, CO2 flushing) hypothesized to have occurred before several Campi Flegrei eruptions could have removed earlier-grown crystals from their equilibrium melts. Moreover, our new results indicate that, in the case of complex systems such as Campi Flegrei’s, in which different pre-eruptive processes can modify the equilibrium composition of the crystals, one single geothermobarometric method offers little chance to constrain the magma storage conditions. Conversely, combined methods yield more robust results in agreement with estimates obtained in previous independent studies based on both petrological and geophysical methods.
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Inflating Source Imaging and Stress/Strain Field Analysis at Campi Flegrei Caldera: The 2009–2013 Unrest Episode. REMOTE SENSING 2021. [DOI: 10.3390/rs13122298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, we analyze the 2009–2013 uplift phenomenon at Campi Flegrei (CF) caldera in terms of temporal and spatial variations in the stress/strain field due to the effect of an inflating source. We start by performing a 3D stationary finite element (FE) modeling of X-band COSMO-SkyMed DInSAR and GPS mean velocities to retrieve the geometry and location of the deformation source. The modeling results suggest that the best-fit source is a three-axis oblate spheroid ~3 km deep, which is mostly elongated in the NE–SW direction. Furthermore, we verify the reliability of model results by calculating the total horizontal derivative (THD) of the modeled vertical velocity component; the findings emphasize that the THD maxima overlap with the projection of source boundaries at the surface. Then, we generate a 3D time-dependent FE model, comparing the spatial and temporal distribution of the shear stress and volumetric strain with the seismic swarms beneath the caldera. We found that low values of shear stress are observed corresponding with the shallow hydrothermal system where low-magnitude earthquakes occur, whereas high values of shear stress are found at depths of about 3 km, where high-magnitude earthquakes nucleate. Finally, the volumetric strain analysis highlights that the seismicity occurs mainly at the border between compression and dilatation modeled regions, and some seismic events occur within compression regions.
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Anatomy of the Bezymianny volcano merely before an explosive eruption on 20.12.2017. Sci Rep 2021; 11:1758. [PMID: 33469148 PMCID: PMC7815830 DOI: 10.1038/s41598-021-81498-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/04/2020] [Indexed: 11/08/2022] Open
Abstract
Strong explosive eruptions of volcanoes throw out mixtures of gases and ash from high-pressure underground reservoirs. Investigating these subsurface reservoirs may help to forecast and characterize an eruption. In this study, we compare seismic tomography results with remote sensing and petrology data to identify deep and subaerial manifestations of pre-eruptive processes at Bezymianny volcano in Kamchatka shortly before its violent explosion on December 20, 2017. Based on camera networks we identify precursory rockfalls, and based on satellite radar data we find pre-eruptive summit inflation. Our seismic network recorded the P and S wave data from over 500 local earthquakes used to invert for a 3D seismic velocity distribution beneath Bezymianny illuminating its eruptive state days before the eruption. The derived tomography model, in conjunction with the presence of the high-temperature-stable SiO2 polymorph Tridymite in juvenile rock samples , allowed us to infer the coexistence of magma and gas reservoirs revealed as anomalies of low (1.5) and high (2.0) Vp/Vs ratios, respectively, located at depths of 2-3 km and only 2 km apart. The reservoirs both control the current eruptive activity: while the magma reservoir is responsible for episodic dome growth and lava flow emplacements, the spatially separated gas reservoir may control short but powerful explosive eruptions of Bezymianny.
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Deep Electrical Resistivity Tomography for a 3D picture of the most active sector of Campi Flegrei caldera. Sci Rep 2019; 9:15124. [PMID: 31641176 PMCID: PMC6805934 DOI: 10.1038/s41598-019-51568-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/28/2019] [Indexed: 12/02/2022] Open
Abstract
The central sector of the Campi Flegrei volcano, including the Solfatara maar and Pisciarelli fumarole field, is currently the most active area of the caldera as regards seismicity and gaseous emissions and it plays a significant role in the ongoing unrest. However, a general volcano-tectonic reconstruction of the entire sector is still missing. This work aims to depict, for the first time, the architecture of the area through the application of deep Electrical Resistivity Tomography. We reconstructed a three-dimensional resistivity model for the entire sector. Results provide useful elements to understand the present state of the system and the possible evolution of the volcanic activity and shed solid bases for any attempt to develop physical-mathematical models investigating the ongoing phenomena.
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Thermal Energy Release Measurement with Thermal Camera: The Case of La Solfatara Volcano (Italy). REMOTE SENSING 2019. [DOI: 10.3390/rs11020167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Quiescent volcanoes dissipate a large part of their thermal energy through hot soils and ground degassing mainly in restricted areas called Diffuse Degassing Structures. La Solfatara crater represents the main spot of thermal release for the Campi Flegrei volcano (Italy) despite its reduced dimensions with regards to the whole caldera. The purpose of this study was to develop a method to measure thermal energy release extrapolating it from the ground surface temperature. We used imaging from thermal cameras at short distances (1 m) to obtain a mapping of areas with thermal anomalies and a measure of their temperatures. We built a conceptual model of the energy release from the ground to atmosphere, which well fits the experimental data taken in the La Solfatara crater. Using our model and data, we could estimate the average heat flux in a portion of the crater as q a v g = 220 ± 40 W / m 2 , compatible with other measurements in literature.
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Anatomy of the Campi Flegrei caldera using Enhanced Seismic Tomography Models. Sci Rep 2018; 8:16254. [PMID: 30389977 PMCID: PMC6214947 DOI: 10.1038/s41598-018-34456-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 10/05/2018] [Indexed: 11/09/2022] Open
Abstract
Campi Flegrei caldera (Southern Italy) is a densely inhabited area and suffered several unrest episodes in the last centuries. The dynamic of the caldera is highly debated because of conflicting interpretations. Here we present a detailed reconstruction of the Campi Flegrei structure obtained using the microseismicity recorded during the 1984 unrest. Enhanced Seismic Tomography models obtained with these data allow us describing seismic velocities, attenuation, and scattering patterns. Results show: (1) a plumbing system with a diameter of 1 km located between 2.3 km and 4 km depth (2) a 0.5 km thick caprock located at 2 km depth interpreted as the main structure regulating the fluid interchange between deep and shallow sectors of the caldera, (3) the shape and volume of a shallow reservoir beneath the city of Pozzuoli; this reservoir played a key role during the 1982-1984 unrest, (4) several small reservoirs beneath the main craters of the caldera. All these features fit into the debated question on magmatic or hydrothermal mechanism driving the caldera deformation resulting of crucial importance to allow a better assessment of the hazard.
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Petrosino S, Cusano P, Madonia P. Tidal and hydrological periodicities of seismicity reveal new risk scenarios at Campi Flegrei caldera. Sci Rep 2018; 8:13808. [PMID: 30217987 PMCID: PMC6138717 DOI: 10.1038/s41598-018-31760-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/15/2018] [Indexed: 12/01/2022] Open
Abstract
The volcano-tectonic seismicity occurring at Campi Flegrei caldera during its present unrest phase, started in 2005, is distributed into time-clustered events emerging from a background composed of earthquakes with higher inter-arrival times. Here, we show that clustered seismicity is cyclically recurrent at time scales from semidiurnal to annual, matching tidal and hydrological periodicities. These results suggest that volcano-tectonic seismicity at Campi Flegrei caldera is driven by both variations in the deep magmatic feeding system and exogenous phenomena, as rainfall or global inflation/deflation cycles of the Earth’s crust, controlled by the lunisolar interaction. Consequently, the role of exogenous triggers in the evolution of the present unrest phase should be properly considered in the elaboration of volcanic risk scenarios, presently limited to the study of surface indicators of deep phenomena.
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Affiliation(s)
- Simona Petrosino
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli - Osservatorio Vesuviano, via Diocleziano 328, 80124, Napoli, Italy
| | - Paola Cusano
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli - Osservatorio Vesuviano, via Diocleziano 328, 80124, Napoli, Italy
| | - Paolo Madonia
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, via Ugo La Malfa 153, 90146, Palermo, Italy.
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Structure of Volatile Conduits beneath Gorely Volcano (Kamchatka) Revealed by Local Earthquake Tomography. GEOSCIENCES 2017. [DOI: 10.3390/geosciences7040111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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De Siena L, Chiodini G, Vilardo G, Del Pezzo E, Castellano M, Colombelli S, Tisato N, Ventura G. Source and dynamics of a volcanic caldera unrest: Campi Flegrei, 1983-84. Sci Rep 2017; 7:8099. [PMID: 28808286 PMCID: PMC5556014 DOI: 10.1038/s41598-017-08192-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/07/2017] [Indexed: 11/09/2022] Open
Abstract
Despite their importance for eruption forecasting the causes of seismic rupture processes during caldera unrest are still poorly reconstructed from seismic images. Seismic source locations and waveform attenuation analyses of earthquakes in the Campi Flegrei area (Southern Italy) during the 1983-1984 unrest have revealed a 4-4.5 km deep NW-SE striking aseismic zone of high attenuation offshore Pozzuoli. The lateral features and the principal axis of the attenuation anomaly correspond to the main source of ground uplift during the unrest. Seismic swarms correlate in space and time with fluid injections from a deep hot source, inferred to represent geochemical and temperature variations at Solfatara. These swarms struck a high-attenuation 3-4 km deep reservoir of supercritical fluids under Pozzuoli and migrated towards a shallower aseismic deformation source under Solfatara. The reservoir became aseismic for two months just after the main seismic swarm (April 1, 1984) due to a SE-to-NW directed input from the high-attenuation domain, possibly a dyke emplacement. The unrest ended after fluids migrated from Pozzuoli to the location of the last caldera eruption (Mt. Nuovo, 1538 AD). The results show that the high attenuation domain controls the largest monitored seismic, deformation, and geochemical unrest at the caldera.
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Affiliation(s)
- Luca De Siena
- University of Aberdeen, School of Geosciences, Dept. Geology and Petroleum Geology, Meston Building, King's College, Aberdeen, AB24 3UE, Scotland, UK.
| | - Giovanni Chiodini
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Via D. Creti 12, 40128, Bologna, Italy
| | - Giuseppe Vilardo
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli-Osservatorio Vesuviano, Via Diocleziano 328, 80124, Napoli, Italy
| | - Edoardo Del Pezzo
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli-Osservatorio Vesuviano, Via Diocleziano 328, 80124, Napoli, Italy.,Instituto Andaluz de Geofisica, Universidad de Granada, Calle Prof. Clavera, Campus Universitario de Cartuja, Granada, Spain
| | - Mario Castellano
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli-Osservatorio Vesuviano, Via Diocleziano 328, 80124, Napoli, Italy
| | - Simona Colombelli
- Department of Physics, University of Naples Federico II, Napoli, Italy
| | - Nicola Tisato
- The University of Texas at Austin, Jackson School of Geosciences, Department of Geological Sciences, 2275 Speedway Stop C9000, Austin, TX, 78712, USA.,Dept. of Civil Engineering, University of Toronto, 35 St. George St., M5S 1A4, Toronto, Ontario, Canada
| | - Guido Ventura
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Roma, Via di Vigna Murata 605, 00181, Roma, Italy.,Istituto per l' Ambiente Marino Costiero, CNR, Napoli, Italy
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De Landro G, Serlenga V, Russo G, Amoroso O, Festa G, Bruno PP, Gresse M, Vandemeulebrouck J, Zollo A. 3D ultra-high resolution seismic imaging of shallow Solfatara crater in Campi Flegrei (Italy): New insights on deep hydrothermal fluid circulation processes. Sci Rep 2017; 7:3412. [PMID: 28611382 PMCID: PMC5469761 DOI: 10.1038/s41598-017-03604-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 05/09/2017] [Indexed: 11/09/2022] Open
Abstract
Seismic tomography can be used to image the spatial variation of rock properties within complex geological media such as volcanoes. Solfatara is a volcano located within the Campi Flegrei, a still active caldera, so it is of major importance to characterize its level of activity and potential danger. In this light, a 3D tomographic high-resolution P-wave velocity image of the shallow central part of Solfatara crater is obtained using first arrival times and a multiscale approach. The retrieved images, integrated with the resistivity section and temperature and the CO2 flux measurements, define the following characteristics: 1. A depth-dependent P-wave velocity layer down to 14 m, with Vp < 700 m/s typical of poorly-consolidated tephra and affected by CO2 degassing; 2. An intermediate layer, deepening towards the mineralized liquid-saturated area (Fangaia), interpreted as permeable deposits saturated with condensed water; 3. A deep, confined high velocity anomaly associated with a CO2 reservoir. These features are expression of an area located between the Fangaia, water saturated and replenished from deep aquifers, and the main fumaroles, superficial relief of the deep rising CO2 flux. Therefore, the changes in the outgassing rate greatly affect the shallow hydrothermal system, which can be used as a “mirror” of fluid migration processes occurring at depth.
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Affiliation(s)
- Grazia De Landro
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy.
| | - Vincenzo Serlenga
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy.,Now at Consiglio Nazionale delle Ricerche, Istituto di Metodologie per l'Analisi Ambientale, Tito, Italy
| | - Guido Russo
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy
| | - Ortensia Amoroso
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy
| | - Gaetano Festa
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy
| | - Pier Paolo Bruno
- Petroleum Institute, Department of Petroleum Geosciences, Abu Dhabi, United Arab Emirates
| | | | | | - Aldo Zollo
- Department of physics "Ettore Pancini", University of Naples "Federico II", Naples, Italy
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Aiello G, Giordano L, Giordano F. High-resolution seismic stratigraphy of the Gulf of Pozzuoli (Naples Bay) and relationships with submarine volcanic setting of the Phlegrean Fields volcanic complex. RENDICONTI LINCEI 2016. [DOI: 10.1007/s12210-016-0573-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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