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Di Giuseppe, Maria Giulia
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Di Giuseppe, Maria Giulia
Email
mariagiulia.digiuseppe@ingv.it
Staff
staff
ORCID
Researcher ID
A-2421-2012
33 results
Now showing 1 - 10 of 33
- PublicationRestrictedGeothermal Investigations of Active Volcanoes: The Example of Ischia Island and Campi Flegrei Caldera (Southern Italy)(2015)
; ; ; ; ; ; ; ; ; ; ; The active volcanic zone of Ischia Island and Campi Flegrei caldera (Campania) have been the site of many geothermal investigations, since the early 20th century. These areas are characterized by very high geothermal gradient and heat flow as consequence of upward migration of magmatic sources coupled with vigorous hydrothermal circulation. After the increment of installed geothermal power in Larderello (Tuscany), the extensive geothermal exploration of Campania was not followed by exploitation projects. In recent time, the attention on the possibility to exploit electric energy has been drawn by the new Italian regulation for exploitation leases. The larger geothermal potential of Campi Flegrei caldera and Ischia Island, located west to the Bay of Naples, makes these areas as possible sites of new geothermal plants installation. We present here the results of recent geothermal researches of Campi Flegrei caldera and Ischia Island, which integrate and improve the information obtained during the exploration performed by SAFEN and AGIP-ENEL companies from the earlier 1940 to 1985. These data are useful to characterize the geothermal reservoirs of this active volcanoes and also to increase the knowledge of volcanic processes and related risk.120 9 - PublicationOpen AccessThe role of stress-dependent permeability in enhanced geothermal systems modelling(2014-07-02)
; ; ; ; ; ; ; We present a procedure for testing the interpretation of the induced seismicity. The procedure is based on Coulomb stress changes induced by deep fluid injection during well stimulation, providing a way to estimate how the potential for seismic failure in different volumes of a geothermal reservoir might change due to the water injection. It was successfully applied to reproduce the observations collected during and after the complex stimulation cycle of the GPK2 and GPK3 wells at the Soultz sous Foret Enhanced Geothermal System EGS site (Alsace, France). In this paper, a conceptual model that links the induced stress tensor and the permeability modifications is considered, with the aim to estimate the permeability change induced during the water injection. In this way, we can adapt the medium behaviour to mechanical changes, in order to better evaluate the effectiveness of the stimulation process for the enhancement of the reservoir permeability, while also refining the reconstruction of the Coulomb stress change patterns. Numerical tests have been developed that consider a physical medium comparable with the granitic basement of the Soultz EGS site, and a geometry of the system that is compatible with that of the GPK2-GPK3 wells. In such a way, the forecasting of the areas of higher likelihood for induced seismicity results in a good agreement between Coulomb stress change patterns and induced seismicity.89 37 - PublicationOpen AccessAbout the shallow resistivity structure of Vesuvius volcano(2008-02)
; ; ; ; ; ; ; ; ;Troiano, A.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Petrillo, Z.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Di Giuseppe, M. G.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Balasco, M.; Istituto di Metodologie per l’Analisi Ambientale (IMAA, CNR), Tito Scalo (Pz), Italy ;Diaferia, I.; Dipartimento di Geologia e Geofisica, Università degli Studi di Bari, Italy ;Di Fiore, B.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Siniscalchi, A.; Dipartimento di Geologia e Geofisica, Università degli Studi di Bari, Italy ;Patella, D.; Dipartimento di Fisica, Università degli Studi di Napoli «Federico II», Napoli, Italy; ; ; ; ; ; ; Magnetotelluric (MT) soundings performed in the past in the volcanic area of Mt. Vesuvius by two independent research groups showed in the same places MT apparent resistivity curves with very similar shape, but statically shifted by one order of magnitude, at least. To try to resolve this ambiguity new controlled source audio-magnetotelluric (CSAMT) measurements have been carried out in the same MT sites. The interpretation of the CSAMT dataset, combined with that of two shallow dipole-dipole geoelectrical resistivity tomographies previously carried out in the area have allowed a reliable electrical structure to be recovered down to a few km of depth, which will next be used for a best constrained re-interpretation of the deep MT soundings.449 746 - PublicationRestrictedThe geothermal system of Ischia Island (southern Italy): Critical review and sustainability analysis of geothermal resource for electricity generation(2014)
; ; ; ; ; ; ; ; ; ; ; In this paper we analyze the main available data related to the geothermal system of Ischia Island, starting from the first geothermal exploration in 1939. Our aim is to define a conceptual model of the geothermal reservoir, according to geological, geochemical, geophysical and stratigraphic data. In recent times, the interest on geothermal exploitation for electricity generation in Italy is rapidly increasing and the Ischia Island is one of the main targets for future geothermal exploitation. Nowadays, one of the main economic resources of the island is the tourism, mainly driven by the famous thermal springs; so, it is crucial to study the possible interaction between geothermal exploitation and thermal spring activities. To this aim, we also analyze the possible disturbance on temperature and pressure in the shallow geothermal reservoir, due to the heat withdrawal for electric production related to small power plant size (1e5 MWe). Such analysis has been performed by using numerical simulations based on a well known thermofluid-dynamical code (TOUGH2!). Obtained results show that such geothermal exploitation generates a perturbation of temperature and pressure field which, however, is confined in a small vol- ume around the well. At shallow level (0e100 m) the exploitation does not produce any appreciable disturbance, and can be made compatible with thermal spring exploitation. Moreover, such results are crucial both for the evaluation of volcanological processes in the island and for the general assessment of geothermal resource sustainability.300 5 - PublicationOpen AccessA geophysical k-means cluster analysis of the Solfatara-Pisciarelli volcano-geothermal system, Campi Flegrei (Naples, Italy)(2018)
; ; ; ; ; ; ; ;; We present an application of the k-means cluster analysis technique to a trivariate geophysical parameter set dis- tributed over a 3 km thick and 1.2 km long section through the geothermally active Solfatara-Pisciarelli area of the Campi Flegrei caldera (Italy). The data set consists of resistivity, P-wave velocity and density parameters, ex- tracted from previously modeled univariate sections through the selected profile and mapped in a joint param- eter 3D space. Six compact and separated clusters have been identified. A subsequent linear regression statistics has allowed two distinct branches of clusters to be recognized, each represented in the joint parameter space by the equation of a plane. Each equation and its partial derivatives define the peculiar combinations among the used parameters. Once mapped back to the space domain, the final image has provided a grouping of the struc- tures in two superimposed blocks with an irregular interface located at 2 km mean depth. Based on drilling data, subsurface stratigraphy and recent seismic activity, the interface between the two blocks has been interpreted in terms of a substantial change in the rocks rheology inside the Solfatara-Pisciarelli volcano-geothermal system, namely the brittle-to-ductile transition.332 520 - PublicationOpen AccessDeep Electrical Resistivity Tomography for a 3D picture of the most active sector of Campi Flegrei caldera(2019-10-22)
; ; ; ; ; ; ; ; ; 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.77 41 - PublicationOpen AccessStructure and Present State of the Astroni Volcano in the Campi Flegrei Caldera in Italy Based on Multidisciplinary Investigations(2022-11-17)
; ; ; ; ; ; ; ; ; ; ; ; ; Despite its known reconstructed volcanic history, the structural setting and present state of the Astroni Volcano of the Campi Flegrei caldera in Italy are still poorly defined. Through structural, geophysical, and geochemical investigations, we elucidate the structure and present volcanic activity of the Astroni Volcano, which hosts tuff cones, scoriae cones, lava domes, and lakes on the crater floor. A volcano-tectonic analysis focused on the entire volcano edifice, coupled with electrical resistivity tomography of the shallower part of the Astroni crater, revealed the main rock formations, faults, and possible fluid patterns within the first 150 m depth. Two main NE–SW and NW–SE trending fault sets were imaged using electrical resistivity modeling and measurements along the wall of the volcanic edifice; they likely delimit a maar-like structure resulting from the highest nergetic subplinian Astroni 6 eruption event and acted as magma pathways during the late eruptive activity stage. A 3D view of the reconstructed resistivity model revealed both deep root-conduit-like structures and shallower dome-like shapes for volcanic edifices on the crater floor. Gas and carbon compositions in the NNE sectors of the Astroni Lago Grande are similar to those of the Solfatara fumarole fluids, suggesting common hydrothermal origin and a possible link with a deep hydrothermal reservoir. This fluid-emission area along the border of the younger volcanic structure exhibits a +40°C maximum soil-temperature anomaly. The proposed volcano-tectonic architecture should improve the unrest scenarios in case of reactivation in this Campi Flegrei caldera sector and the monitoring strategies for the Astroni Volcano.262 114 - PublicationRestrictedSeparation of plain wave and near field contributions in Magnetotelluric time series: A useful criterion emerged during the Campi Flegrei (Italy) prospecting(2018)
; ; ; ; ; The presence of coherent noise in the Magnetotelluric time series greatly obstacles the application of this pow- erful technique in highly urbanized environments. Here the experiences gained during an intensive prospecting of the Campi Flegrei caldera (Italy) are described. In this area the presence of an extensive electrified railroad comports the contamination of the electromagnetic signal by high level of noise related to randomly moving sources. The main task consists in the search for a way to discern the plain wave signal from the noise. This has been achieved through a first application of the well-known Robust Multivariate Errors-in-Variables (RMEV) estimator to the time series collected in the area in order to characterize the global structure of the signal and then through various tests performed on both synthetic and real field Magnetotelluric data. In the end, an empirical criterion has been deduced, based on the rotational analysis of the dominant eigenvectors of the time series Spectral Density Matrix, apt to isolate the plain wave component of the Magnetotelluric data. A var- iation of the standard RMEV scheme has been successively applied in order to obtain a reliable estimate of the apparent resistivity curves. This application has proven its suitability for the time series collected in the Campi Flegrei area, but the logic at its basis could be a key to deal with more general cases.94 6 - PublicationOpen AccessEditorial: Multidisciplinary Investigations for Determining the Structure and Dynamics of Active Volcanic Systems(2022-06-17)
; ; ; ; ; ; ; ; ;Multidisciplinary investigations are widely considered by the scientific community to be the key strategy for understanding the interplay between magmatic processes and volcanic structures as a primary task for volcanological research. Integrating geophysical, geochemical and geological datasets has the potential to provide accurate constraints on the characteristics of volcanic structures and their impact on magma storage and eruption. This Research Topic aims to provide a coherent selection of recent achievements in different aspects of volcanology, geophysics, petrology and/or geochemistry to provide new information about the structure and dynamics of active volcanic and magmatic systems. The presented contributions include the application of laboratory to field-based experimental or modelling studies, geophysics methods and their development and integration post-inversion for the investigations of active volcanic areas.35 10 - PublicationOpen AccessThe Pisciarelli main fumarole mechanisms reconstructed by electrical resistivity and induced polarization imaging(2021-09-20)
; ; ; ; ; ; ; Pisciarelli, together with the adjacent Solfatara maar-diatreme, represents the most active structure of the Campi Flegrei caldera (Italy) in terms of degassing and seismic activity. This paper aims to define the structure of the Pisciarelli hydrothermal system (down to a 20 m depth) through electrical resistivity and time-domain-induced polarization tomography and self-potential mapping. The retrieved 3D image of the area helps reconstruct the Pisciarelli subsurface in its area of maximum degassing, containing the main fumarole ("soffione") and the mud pool. In particular, a channel has been identified in which fluids stored in a deeper reservoir rise toward the surface. Such a structure seems to be surmounted by a clay-cap formation that could govern the circulation of fluids and the abundance of gases/vapors emitted by the soffione. Based on this new reconstruction of the Pisciarelli fumarolic field structural setting, the first conceptual model has been suggested that is capable of simultaneously explaining the mechanisms governing soffione activity and elucidating the role played by the fluid/gas of deeper origin in the shallow fluid circulation system. The proposed model can potentially help to better monitor the processes occurring throughout the Pisciarelli fumarolic field and provide an evaluation of the associated hazards.45 13