1,368,785 research outputs found
Volcanic Hazard Assessment at the Campi Flegrei Caldera, Italy
No full textThe Campi Flegrei caldera is a complex and resurgent structure, and its active portion has been the site of an intense volcanism with eruptions concentrated in temporal clusters, called epochs. The caldera is home to about 350,000 people. In the past decades, many scientific studies were aimed at both defining fundamental parameters of a future eruption, and hazard zoning of the territory. The approach to the volcanic hazard assessment of the Campi Flegrei caldera has progressively changed through time from a “deterministic” interpretation of the available information to a quantitative probabilistic elaboration of the main sources of uncertainty. In
particular, on the long-term, Astroni-Agnano-Solfatara is recognised to be the most probable area in which a vent will likely open, while the Averno-Monte Nuovo is the second most probable one. Significant uncertainty affects these results, and a non-negligible vent opening probability spreads over the whole caldera. The inter-event times of volcanic eruptions span from a few years to thousands of years. Within the epochs of activity, the mean recurrence time is tens of years, and intra-epoch temporal groups are evident. The probability that the next eruption will be of < 0.1 km3 volume of magma DRE is *95%. Larger size eruptions tend to be
localised in the central-eastern sector of the caldera. Expected hazards from renewal of explosive volcanism result from pyroclastic fallout and pyroclastic density currents. Pyroclastic fallout deposits in excess of 300 kg/m2 can affect most of the caldera and the city of Naples with more than 10% probability. The entire caldera has the potential to be affected by pyroclastic density currents invasion with mean probability above 30% in its central-eastern portion, and above 50% in the Agnano area. Invasion probabilities of ca. 5–10% have been estimated for the urbanised areas along the eastern slopes of the Posillipo Hill. In summary, probabilistic hazard assessment is particularly important in Campi Flegrei caldera, due to the uncertain location for potential vents and the large variability of eruption styles and sizes that cannot be, at the present time, effectively constrained by monitoring signals.Published311–3556V. Pericolosità vulcanica e contributi alla stima del rischi
The Permanent Monitoring System of the Campi Flegrei Caldera, Italy
No full textWe present the main features of the permanent monitoring system managed by the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Vesuviano in the Campi Flegrei caldera. Eruptive history of this active volcano shows that the majority of the eruptive events has been characterised by high explosivity and was accompanied by pyroclastic density currents. Its last eruption occurred in AD 1538 and in the next centuries the Campi Flegrei caldera has experienced several episodes of bradyseism and also the progressive increasing of the urbanisation in the area (west of Naples). Monitoring the dynamics of a mainly explosive volcano completely embedded in a very populated area is a challenging task. In order to detect any variation in the physical and chemical parameters of the Campi Flegrei caldera, the Istituto Nazionale di Geofisica e
Vulcanologia-Osservatorio Vesuviano manages a permanent multi-parametric monitoring system. All the recorded h24 continuous data are transmitted to the Monitoring Room of the Osservatorio Vesuviano in Naples, where they are acquired, processed and evaluated to define changes in the dynamical state of the volcano. The caldera, since the end of 2004, is experiencing a bradyseismic episode characterised by a low velocity rate uplift, low energy earthquakes and increasing in the magmatic components of fumarolic fluids.
The monitoring and surveillance activity of the Campi Flegrei caldera plays a crucial role in the volcanic emergency plan that includes evacuation of approximately 500,000 people before the beginning of the eruption.Published219-2376SR VULCANI – Servizi e ricerca per la società1IT. Reti di monitoraggio e sorveglianza2IT. Laboratori analitici e sperimentali4IT. Banche dat
Trophic niche of cave populations of Speleomantes italicus
No full textVignoli, Leonardo, Caldera, Federico, Bologna, Marco A. (2006): Trophic niche of cave populations of Speleomantes italicus. Journal of Natural History 40 (29-31): 1841-1850, DOI: 10.1080/00222930600973598, URL: http://dx.doi.org/10.1080/0022293060097359
De pulvere febrifugo occidentalis indiae (1663) de Gaspar Caldera de Heredia y la introducción de la quina en Europa
No full textGaspar Caldera de Heredia y su “De Pulvere Febrifugo Occidentalis Indiae”. Girolamo Bardi y los cardenales Brancaccio y de Lugo. Juan de Vega, introductor de la quina en Europa, según Gaspar Caldera de Heredia. Los testimonios complementarios de Bravo de Sobremonte, Miguel de Heredia y Salado Garcés. El estudio farmacológico de la quina por Gaspar Caldera de Heredia. Texto: Gaspar Caldera de Heredia, “Acerca del polvo Febrifugo de la India Occidental” (1663)//. Gaspar Caldera de Heredia i el seu "De Pulvere Febrifugo Occidentalis Indiae". Girolamo Bardi i els cardenals Brancaccio i de Lugo. Juan de Vega, introductor de la quina a Europa, segons Gaspar Caldera de Heredia. Els testimoniatges complementaris de Bravo de Sobremonte, Miguel de Heredia i Salado Garcés. L'estudi farmacològic de la quina per Gaspar Caldera de Heredia. Text: Gaspar Caldera de Heredia, “Acerca del polvo Febrifugo de la India Occidental” (1663)
GENOVA CITTA' D'ARTE: LO SVILUPPO URBANISTICO (PP. 8-27); CHIESA E CONVENTO DI SANTA MARIA DI CASTELLO (PP. 66-77); COMMENDA DI SAN GIOVANNI DPRE' (PP. 78-83); CHIESA DI SAN DONATO (PP. 84-91); PALAZZO DUCALE (PP. 94-107); PIAZZA SAN MATTEO (PP. 108-119); LE ARCHITETTURE CIVILI (PP. 120-121); PALAZZO DEL PRINCIPE (PP. 122-135); STRADA NUOVA (PP. 136-149); GALEAZZO ALESSI A GENOVA (PP. 150-151); STRADA BALBI (PP. 152-165); VILLA DI LUCA GIUSTINIANI (PP. 166-171); L'INCANTESIMO DELLE GROTTE (PP. 172-173); LA CITTA' FORTIFICATA (PP. 174-183); TEATRO CARLO FELICE (PP. 184-191); PORTO ANTICO (PP. 202-207); LUCA CAMBIASO TRA MITO, PITTURA SACRA E PITTURA DI STORIA (PP. 270-277); QUATTRO CAPOLAVORI PER IL SECOLO D'ORO NELLA CHIESA DEL GESU' (PP. 278-285); COMMITTENZA E COLLEZIONISMO BRIGNOLE-SALE (PP. 322-335); IL CIMITERO MONUMENTALE DI STAGLIENO (PP. 338-347); FRANCO ALBINI E I MUSEI DI GENOVA (PP. 366-371).
No full textHydrothermal fluid circulation and its effect on caldera unrest
No full textThis paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.Accepted3.6. Fisica del vulcanismo4.3. TTC - Scenari di pericolosità vulcanicaope
The Hydrothermal System of the Campi Flegrei Caldera, Italy
No full textIn this chapter, we review the state-of-the-art of the Campi Flegrei caldera (Naples) hydrothermal system, and its behaviour during the last decades. The Campi Flegrei caldera has been undergoing unrest since 1950, as
evidenced by recurrent bradyseismic episodes accompanied by manifest changes in the degassing budget, degassing patterns and in the composition of the fumarolic fluids. caldera. We propose a conceptual model of
the hydrothermal system feeding Solfatara fumaroles, where geochemical information is integrated with Audio Magneto Telluric measurements, which yields a realistic picture of the geometry of the system up to a depth of
2.5 km. The model identifies a 2 km elongated vertical high resistivity structure in axis with the Solfatara fumaroles, which represents a relatively high permeability zone allowing hot fluid ascent from depth to the shallower portions of the hydrothermal system. Pulsed injections of hot magmatic fluids (CO2-rich and CH4-poor oxidised fluids) at the bottom of the hydrothermal system is thought to be one of the key processes that has controlled the evolution of the system during the last 40 years. The episodes of injection of magmatic fluids changed in frequency and intensity during time, ultimately causing an overall heating and pressurisation of the
system since the early 2000s, as reflected by escalating degassing flux, increase in areal extension of the degassing areas, and in the composition of the fumaroles. In particular, the CO2/CH4 and He/CH4 ratios of fumarolic fluids exhibited recurrent peaks, marking the episodes of injection of magmatic fluids. Moreover, the quasi-monotonic increasing trend of the fumarolic CO2/H2O ratio, from 0.15 to 0.18 in 2000 to 0.4 in 2018–2019, has been interpreted as due to the combined action of partial steam condensation, and CO2 addition from a magmatic source and possibly from de-carbonation of hydrothermal calcite favoured by the heating of the hydrothermal reservoir. These changes strongly suggest that the ongoing (since 2000) unrest is triggered by a degassing magma source, but also that the system’s response is modulated by dynamics and structures of the overlying hydrothermal envelope. This evolution clearly requires careful scientific scrutiny and intensified monitoring in the years to come.Published239-25
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An invitation from Thomas Lee Caldera to Dr. Hector P. Garcia.
No full textAn invitation from Thomas Lee Caldera to Dr. Hector P. Garcia for his graduation from Miller High School
Hydrothermal Fluid Circulation and its Effect on Caldera Unrest
No full textThis paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.Published393-4163.6. Fisica del vulcanismo4.3. TTC - Scenari di pericolosità vulcanicareserve
Seismic and Gravity Structure of the Campi Flegrei Caldera, Italy
No full textWe present a comprehensive review of seismic and gravity observations and tomographic models produced over the past four decades in order to understand the structure of the crust beneath the Campi Flegrei caldera. We describe the main lithological and structural discontinuities defined through these observations, illustrate their geophysical responses, and discuss the constraints they give to the understanding of magmatic and volcanic processes. Micro-seismic crises related to caldera unrest, and ambient seismic noise measurements provide comprehensive seismic data to local earthquake and ambient noise tomography. In combination with reflection data from onshore and offshore active seismic experiments, velocity tomography reconstructs the elastic properties of the caldera between surface and ~4 km depth. Active experiments also define the depth of lithological interfaces and deep (~7.5 km) partially molten bodies. Seismic attenuation tomography provides information complementary to velocity tomography, defining lateral lithological changes and the geometry of onshore and offshore fluid and magma bodies down to 4 km depth. Once compared with seismic analyses, gravity data highlight lateral changes in the offshore caldera structures. During the deformation and seismo-geochemical unrest (1982–1984), they permitted to reconstruct a minor (<1 km lateral extent) melt volume related to the point of maximum uplift measured at the caldera. Seismic coda-wave amplitude inversions depict the caldera rim limits in analogy to velocity tomography and map the lateral extension of ~4-km-deep deformation source. Once combined with the results from velocity tomography and gravity inversions, they reconstruct the feeding systems that connect deep deformation source and shallow vents across the eastern caldera, capped by a seismic horizon around a depth of 2 km
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