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Todesco, Micol
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Preferred name
Todesco, Micol
Official Name
Micol Todesco
Email
micol.todesco@ingv.it
Staff
staff
ORCID
Scopus Author ID
6602139646
Researcher ID
B-1216-2012
52 results
Now showing 1 - 10 of 52
- PublicationRestrictedPhysical modelling and human survival in pyroclastic flows(1998)
; ; ; ; ;Volcanic eruptions increasingly present catastrophic natural risks with hundreds of mil- lions of people now living in areas of active volcanism and major conurbations around active eruptive centres. Interdisciplinary studies in disaster reduction have an important role in volcanic emergency management through advancing our understanding of the physical impacts of eruptive phenomena and the causes of death and injury in explosive eruptions. Numerical modelling of pyroclastic flows, amongst the most destructive of eruptive phenomena, provides new opportunities to improve the evaluation of the potential destructiveness of volcanic events and their human impacts in densely populated areas. In this work, the results of numerical modelling of pyroclastic flow propagation at Vesuvius have been analysed in terms of the physical parameters (temperature, ash in air concentra- tion, and dynamic pressure) that are most critical for human survival. Our numerical simulations of eruptions of Vesuvius indicate that a large area exists where total destruction may not be inevitable in small to medium scale events, a finding that has prompted us to explore further the implications for human survival as part of an interdisciplinary approach to disaster reduction. The lessons of mod- elling at Vesuvius should be integrated into civil protection plans for other urban centres threatened by volcanoes.76 4 - PublicationOpen AccessMulti-variate analysis of the monitoring data at Vulcano and Campi Flegrei(2016-11-22)
; ; ; ; ; ; ; ; ; ; ; ; ; This contribution describes the work-in-progress within the project FREAPROB, funded by INGV. The ultimate goal is to seek signals or recurrent patterns within data of different nature (from geochemistry, geodesy, gravity and seismology), which are recorded at two of the best monitored volcanoes in the world, Vulcano and Campi Flegrei (Italy). In fact, despite the strong monitoring effort, the multivariate and objective analysis of the monitoring observations from different disciplines is still uncommon. The first step of our work has been the collection, collation and homogeneization of some of the available data. At Campi Flegrei, the dataset features all published geochemical data from the two main fumaroles (Bocca Grande and Bocca Nuova), gravity residuals, ground displacement and seismic activity, all recorded by Osservatorio Vesuviano in the last decades. This dataset is being analysed in search for recurrent patterns describing periods of higher fumarolic temperature or characterized by greater deformation rate. For the case of Vulcano, data from the continuous monitoring of the crater rim's fumaroles were collated with the records from the monthly surveys that have been carried out in the last 25 years to monitor the largest and most persistent fumaroles at the La Fossa crater. The fumarole observations (consisting of temperature and geochemical variables) were further merged with the observations from the seismic network to constitute the base for a multivariate analysis. Aim of the analysis is the identification of patterns capable of discriminating periods of high and low temperature at the fumaroles, or periods characterized by more intense seismic activity. This contribution underlines and encourages the development of multivariate datasets and databases that allow searching, through objective statistical analysis, signals and patterns that are difficult to extract “by eye”.105 55 - PublicationOpen AccessVolcanic hazard in Italy: a variegated landscape(2021-12)
; ; ; ; ; ; ; ; ; ; ; Southern Italy is one of the most active tectonic and volcanic settings in the Mediterranean area, comprising persistently active and dormant volcanoes. As we write, two volcanoes feature a persistent eruptive activity: Stromboli, belonging to the Aeolian Archipelago, in the Tyrrhenian Sea, and Etna, along the Eastern coast of Sicily. Both volcanoes are usually characterized by mild explosivity featuring the launch of pyroclasts near the vent, occasional lava flows and lava fountains up to several hundreds of meters. This kind of activity may culminate in the development of eruptive columns, which may reach up to 10-15 thousand meters, in the case of Etna.1207 63 - PublicationOpen AccessVertical ground displacement at Campi Flegrei (Italy) in the fifth century: Rapid subsidence driven by pore pressure drop(2014)
; ; ; ; ; ; ; ; ; ; ;Campi Flegrei (Italy) caldera has experienced episodes of ground deformation throughout its geological history, alternating between uplift and subsidence phases. Although uplift periods are typically more alarming, here we focus on subsidence, looking for its driving mechanisms and its role in the caldera evolution. Historical and archaeological records constrain ground deformation over the last two millennia. Here we revise such records and combine them with published radiometric dating and with the simulation of sea level change. The resulting analysis highlights for the first time a rapid subsidence during the fifth century. We show that rate and magnitude of this subsidence are consistent with the compaction of porous material caused by a pressure drop of ~ 1 MPa within the hydrothermal system. We interpret this event as the decompression of the hydrothermal system following an unrecognized episode of unrest, during Roman times. These findings redefine the pattern of ground deformation and bear important implications for volcanic hazard assessment380 169 - PublicationOpen AccessMODELING OF GAS COMPOSITION AND GRAVITY SIGNALS AT THE PHLEGREAN FIELDS CALDERA(2006-05-15)
; ; ; ;Todesco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Chiodini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Berrino, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; Hydrothermal systems are known to play an important role in the evolution of active calderas: these volcanic systems periodically undergo dramatic unrest crises, commonly involving ground deformation, seismic activity and important changes in several geophysical and geochemical parameters monitored at the surface. These unrest crises may, or may not, culminate with a renewal of the eruptive activity, but in any case they bear important consequences in densely populated regions. Early warning and a prompt evaluation of the state of evolution of the volcanic system are therefore essential to ensure proper mitigation measures. A proper interpretation of monitoring data, however, is only achieved within the framework of a robust conceptual model of the system. Recent research work carried out at the Phlegrean Fields shows that the recent evolution of the caldera is consistent with the presence of a pulsating magmatic source, periodically discharging CO2-enriched fluids into a shallow hydrothermal system. Such pulsating degassing affects the amount of heat and fluids entering the hydrothermal system, the distribution of fluid phases throughout the system, and their composition. As a consequence, degassing controls not only the composition of fluids discharged at the surface, but also ground displacement and gravity residuals. In this work, the TOUGH2 code has been applied to study how different degassing scenarios could affect the composition of discharged fluids and the gravity signals recorded at the surface.162 118 - PublicationOpen AccessMONITORING AND MODELLING HYDROTHERMAL PANAREA SYSTEM (AEOLIAN ISLAND): GPS AND VOLCANOLOGICAL DATA(2008-08)
; ; ; ; ; ; ; ; ;Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Pietrantonio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Anzidei, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Giordano, G.; Università Roma Tre Roma, Italy ;Rinaldi, A. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Todesco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; ; ; ; ; ; ; In November 2002 a submarine gas eruption started offshore 3 Km east of Panarea island (Aeolian Island) on top of a shallow rise of 2.3 km2 surrounded by islets forming a small archipelago. This event has posed new concern on a volcano generally considered extinct. Panarea island and its archipelago (~ 3.3 km2) are the emergent portion of submarine stratovolcano more than 2000 m high and 20 Km across; exhalative activity due to a shallow hydrothermal system is well known since historical times. To monitor and study ground deformation associated with anomalous gas emission, a local GPS network (PANAREA) was designed, set up and measured during time span December 2002 - October 2006. The network consists of nine sites (six constructed after 2002) located on Panarea and on the islets. GPS data analysis was performed combining episodic campaigns of Panarea and other local networks located in the Aeolian area, carried out between 1995 and 2006, and data of continuous European and Italian sites. The results show at Panarea volcano two distinct crustal domains characterized by different kinematics and styles of deformation. The merging of GPS and structural data suggest the relationship among gas vent distribution, submarine volcanological structures and ground deformations. The actual distribution of the estimated strain-rate is consistent with the structural setting.The general subsidence and shortening in the islets area can be interpreted as the response of the surface to the variation of the hydrothermal system reservoir which is progressively reducing its pressure after the gas eruption. A simple first order approach to the modelling of the hydrothermal system is the use of Okada sources.To evaluate the coupled thermo-hydro-mechanical processes going on in Panarea, a two-step model will be implemented. The model first involves the simulation of pore pressure and temperature changes due to fluid circulation. Then the mechanical response of the porous rock is calculated based on the linear theory of poro-elasticity.203 224 - PublicationRestrictedCaldera’s Breathing: Poroelastic Ground Deformation at Campi Flegrei (Italy)Ground deformation at Campi Flegrei has fuelled a long-term scientific debate about its driving mechanism and its significance in hazard assessment. In an active volcanic system hosting a wide hydrothermal circulation, both magmatic and hydrothermal fluids could be responsible, to variable degrees, for the observed ground displacement. Fast and large uplifts are commonly interpreted in terms of pressure or volume changes associated with magma intrusion, while minor, slower displacement can be related to shallower sources. This work focuses on the deformation history of the last 35 years and shows that ground deformation measured at Campi Flegrei since 1985 is consistent with a poroelastic response of a shallow hydrothermal system to changes in pore pressure and fluid content. The extensive literature available for Campi Flegrei allows constraining system geometry, properties, and conditions. Changes in pore pressure and fluid content necessary to cause the observed deformation can then be calculated based on the linear theory of poroelasticity. The predicted pore pressure evolution and fluid fluxes are plausible and consistent with available measurements and independent estimates.
161 49 - PublicationOpen AccessMODELING OF HYDROTHERMAL FLUID CIRCULATION AS A TOOL FOR VOLCANIC HAZARD ASSESSMENT(2009-09)
; ; ; ;Rinaldi, A. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Vandemeulebrouck, LGIT, Université de Savoie, Le Bourget du Lac Cedex ;Todesco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; ;Monitoring of geophysical and geochemical observ¬ables at the surface plays a main role in the under¬standing of—and the hazard evaluation of— active volcanoes. Measurable changes in these parameters should occur when a volcano approches eruptive con¬ditions. Hydrothermal activity is commonly studied as an efficient carrier of signals from the magmatic system. As the magmatic system evolves, the amount, temperature, and composition of magmatic fluids that feed the hydrothermal system change, in turn affecting the parameters that are monitored at the surface. Modeling of hydrothermal circulation, as shown in the past, may cause measurable gravity changes and ground deformation. In this work, we extend our previous studies and increase the number of observable parameters to include gas temperature, the rate of diffuse degassing, the extent of the degassing area, and electrical conductivity. The possibility of nonmagmatic disturbance needs to be carefully addressed to ensure a proper estimate of volcanic hazard.162 202 - PublicationOpen AccessRaccontare le Sale Operative dell’INGV attraverso infografiche(2020-10)
; ; ; ; ; ; ; ; ; Una buona comunicazione è un’attività strategica per un istituto di ricerca come l’Istituto Nazionale di Geofisica e Vulcanologia (INGV). Ancora di più lo è quella che riguarda le attività svolte e i risultati conseguiti dalle Sale Operative, su cui si basa la sorveglianza sismica e vulcanica in Italia. Tutte le informazioni relative a fenomeni in corso potenzialmente pericolosi sono accolte con grande interesse e spesso sono oggetto di attenta valutazione da parte delle popolazioni residenti così come dalle istituzioni. In questi casi, una comunicazione efficace non è soltanto opportuna, ma necessaria a garantire una corretta informazione, a creare e mantenere un rapporto di fiducia con la popolazione e a diventare un autorevole punto di riferimento per le notizie relative alla pericolosità sismica e vulcanica. Queste premesse sono necessarie anche per poter contrastare efficacemente il diffondersi di notizie prive di fondamento, o distorte da interessi diversi dalla diffusione della conoscenza scientifica. Le attività svolte e i dati prodotti nelle Sale Operative sono fortemente diversificati. L’Osservatorio Nazionale Terremoti (ONT) gestisce la Rete Sismica Nazionale (RSN), gli Osservatori Vesuviano (OV) ed Etneo (OE) gestiscono reti di monitoraggio multidisciplinari installate su aree vulcaniche attive. In particolare, l’ONT effettua la sorveglianza sismica del territorio nazionale e delle aree limitrofe e, dal 2017, anche il servizio di Allerta Tsunami del CAT per il monitoraggio dei grandi terremoti a scala globale, con particolare attenzione al Mar Mediterraneo, nell’ambito delle attività dell’ICG/NEAMTWS; l’INGVOV effettua la sorveglianza vulcanica per le tre aree del SommaVesuvio, dei Campi Flegrei e dell’isola d’Ischia e la sola sorveglianza sismica per Stromboli; l’INGVOE svolge la sorveglianza sismica e vulcanica per l’area etnea, per Pantelleria e per le Isole Eolie, collaborando con l’INGVOV per la parte sismologica di Stromboli. Le Sale Operative sono il cuore della sorveglianza sismica e vulcanica in Italia, operano ininterrottamente grazie alla rotazione di personale specializzato, organizzata su turni H24, in ogni giorno dell’anno. Si tratta di un sistema complesso, la cui operatività si basa sulla ricezione, elaborazione, comunicazione ed archiviazione di dati che provengono dai sensori delle reti di monitoraggio, distribuite sul territorio nazionale in ragione delle diverse tipologie di fenomeni attesi. Procedure concordate con il Dipartimento di Protezione Civile (DPC) consentono di informare tempestivamente le autorità preposte al variare di specifici parametri. La sorveglianza sismica e vulcanica è garantita dal monitoraggio continuo e simultaneo di diversi parametri, e dalla loro corretta interpretazione. Ciò è possibile anche grazie ad un continuo sforzo tecnologico volto a migliorare l’acquisizione, la trasmissione e l’elaborazione dei segnali, ed alla ricerca scientifica che interpreta i segnali osservati nel quadro coerente delle conoscenze relative ai diversi contesti geologici che caratterizzano il territorio nazionale. La comunicazione al pubblico dei prodotti delle Sale è svolta attraverso la pubblicazione sul sito web dell’Istituto e delle sue sezioni di dati vulcanologici, sismologici, geodetici e geochimici. Mostrare cosa fanno le Sale Operative dell’INGV permette ai cittadini di comprendere quali risorse e competenze vengono spese per garantire la sorveglianza sismica e vulcanica del territorio. L’adozione di soluzioni innovative, con prevalenza di sintetiche rappresentazioni grafiche consente di inserire le informazioni prodotte dalle Sale nel giusto contesto, favorendo così una migliore comprensione del dato geologico e delle sue implicazioni a un pubblico di non esperti. In questo testo si illustra la progettazione e realizzazione di infografiche dedicate alle attività e ai prodotti delle Sale Operative dell’INGV.560 265 - PublicationRestrictedSignals from the Campi Flegrei hydrothermal system: Role of a ‘‘magmatic’’ source of fluids(2009-05-12)
; ;Todesco, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, ItaliaThis is a parametric study that was carried out to investigate the signals generated by a hydrothermal system fed by a pulsating source of magmatic fluids. This study focuses on the effects that selected properties of the source have on the evolution of hydrothermal activity at Campi Flegrei, Italy. Numerical simulations are carried out to describe a multiphase and multicomponent hydrothermal system. Each simulation describes a short unrest phase, followed by a prolonged quiet period. During the unrest, specific properties of the fluid source (flow rate, fluid composition, source size, and unrest duration) are modified with respect to selected baseline values. The evolution of the system is tracked by looking at two parameters that can be monitored in active volcanic areas: the composition of fumarolic gases and gravity changes. The results describe the temporal evolution of these two observables and allow comparisons of the effects of different source properties. All of the simulated unrest events cause measurable changes in gas composition and gravity. For the geometry and system properties considered, these changes always last beyond the end of the unrest period, and can often persist for decades. Fluid flow rate is the source property that mostly affects the observable evolution. Gravity is more sensitive to source properties than gas composition, and it undergoes the largest and quickest changes. The results also highlight the major role that rock properties and initial conditions have in the evolution of these observable signals.237 23