Roberto Isaia

National Institute of Geophysics and Volcanology | INGV · Vesuvius Observatory

This paper presents the results of an original short-period magnetotelluric survey performed on Vulcano Island (Italy). The obtained three-dimensional resistivity model details structures up to 2.5 km depth, hitherto unexplored. The La Fossa caldera area corresponds to a moderate resistive anomaly, which extends down to the resolved depth and likel...

The Roccamonfina volcano is located within the Garigliano Graben (southern Apennines, Italy) and has been active throughout the Middle‐Late Pleistocene. Along its polyphase volcanic history (630–55 ka), including several caldera‐forming eruptions (385–230 ka), several effusive/mildly explosive monogenetic events occurred along the volcano slopes, w...

Nowadays, modeling of tephra fallout hazard is coupled with probabilistic analysis that takes into account the natural variability of the volcanic phenomena in terms of eruption probability, eruption sizes, vent position, and meteorological conditions. In this framework, we present a prototypal methodology to carry out the long-term tephra fallout...

Nowadays, tephra fallout hazard is based on coupling the physical modeling of the tephra dispersion processes with a probabilistic analysis that takes into account the natural variability of the volcanic phenomena in terms of eruption probability, eruption sizes, vent position and meteorological conditions. In this framework, we present a prototypa...

Silicic calderas are among the most unpredictable volcanoes in terms of precursory signals prior to an eruption; hence understanding the past behaviour and defining an adequate structural framework becomes of utmost importance. This is the case of the Campi Flegrei caldera (southern Italy), which last erupted in 1538 AD and is nowadays one of the m...

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, sc...

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...

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 are...

We report the occurrence of several sand liquefac on structures, such as sand dikes, in the stra graphic record of the Campi Flegrei volcano located both inside and outside the caldera. Five sites were analyzed within the caldera and two outside. The grain size analysis of the sand llings indicates that these deposits are very ne to coarse sands ge...

The Campi Flegrei caldera (southern Italy) has over one third of its extension below the sea. Its volcanic history has been characterized by two major caldera forming erup ons, namely the Campanian Ignimbrite (CI) and the Neapolitan Yellow Tu (NYT), at 40 and 15 ka, respec vely. We analyzed high resolu on seismic re ec on pro les allowing us to cha...

The structure of a caldera may influence its activity, making its understanding crucial for hazard assessment. Here, we analysed high-resolution seismic profiles in the Campi Flegrei (southern Italy) offshore sector. We recognized two main fault systems, including those associated with the formation of the caldera and those affecting the resurgent...

Wetlands are well-known as significant sources of CH4 to the atmosphere, whereas lakes are commonly considered as sinks for C-bearing volatiles produced within bottom sediments. In this work, we present the results of two surveys (summer 2020 and winter 2021, respectively) carried out at the 300×200 m wide Lake Astroni (Phlegraean Fields, southern...

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...

We report the occurrence of several sand liquefaction structures, such as sand dikes, in the stratigraphic record of the Campi Flegrei volcano, located both inside and outside the caldera. Five sites were analyzed within the caldera and two outside. The grain size analysis of the sand fillings indicates that these deposits are very fine-to-coarse s...

Explosive activity preceding the ~40 ka Campanian Ignimbrite (CI) eruption in the Neapolitan volcanic area, Southern Italy, has long been speculated based on the occurrences of widespread tephra layers, with a Campanian geochemical signature, such as the C-22, X-5, and X-6, preserved in Mediterranean Marine Isotope Stage (MIS) 5 sedimentary records...

Silicic calderas are volcanic systems whose unrest evolution is more unpredictable than other volcano types because they often do not culminate in an eruption. Their complex structure strongly influences the post‐collapse volcano‐tectonic evolution, usually coupling volcanism and ground deformation. Among such volcanoes, the Campi Flegrei caldera (...

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 polarizati...

Phreatic and hydrothermal eruptions are small energetic explosive events that generally have few to no precursors and represent a considerable hazard in tourist and urban areas. At the Campi Flegrei caldera, these events have occurred at the Solfatara volcano and have likely occurred at the nearby Pisciarelli site, where the most powerful hydrother...

Pyroclastic density currents are ground hugging gas-particle flows that originate from the collapse of an eruption column or lava dome. They move away from the volcano at high speed, causing devastation. The impact is generally associated with flow dynamic pressure and temperature. Little emphasis has yet been given to flow duration, although it is...

The calculation of the magnitude of an eruption needs the accurate estimate of its deposit volume. This is particularly critical for ignimbrites as no methods for their volume calculations and associated errors and uncertainties are consolidated in the literature, although invariably the largest magnitude eruptions on Earth are made of ignimbrites....

Processes of crystal-mush remobilization bymaficmagma recharges are often related to the outpouring of large volumes of silicic melt during caldera-forming eruptions. This occurred for the Campanian Ignimbrite (CI) eruption (Campi Flegrei, Italy), which produced a voluminous trachy-phonolitic ignimbrite in southern-central Italy about 40 ka ago.We...

The Campi Flegrei caldera (Italy) has been undergoing unrest over the past five decades including episodes of rapid ground deformation, seismicity, and variations in gas emissions. Hydrothermal fluids and gases are released most vigorously in the central sector of the caldera at the fumarolic fields of Solfatara volcano and Pisciarelli. We conducte...

In this paper, we present results of the reconstruction of the total grain size distribution (TGSD) of the material erupted during explosive volcanic eruptions at Campi Flegrei (Italy) considering all components (juvenile, lithic and crystal clasts). To date, the few TGSDs made available have been mostly reconstructed by assuming that the tephra de...

In this study we performed a structural survey on fractures, faults, and dikes. The latter structures are hosted in Mesozoic carbonates exposed in the Presenzano quarry and Pleistocene breccias near Presenzano town, northeast to the Roccamonfina volcano. In order to carry out petrographic and chemical analyses, we collected several samples, in the...

This work focuses on the characterization of deformation structures hosted in the post NYT (15 ka) sequence in both continental and marine areas of Campi Flegrei caldera. A structural survey has been carried out on the rocks exposed on­land. Measurements of fractures, faults, and sedimentary dikes have been collected and analyzed, as well as their...

Mulitdisciplinary Volcanological Reaserach

This study presents a new method, called the Radial Interpolation Method, to interpolate data characterized by an approximately radial pattern around a relatively constrained central zone, such as the ground deformation patterns shown in many active volcanic areas. The method enables the fast production of short-term deformation maps on the base of...

The Campi Flegrei caldera (southern Italy) is characterized by over one­third of its extension lying below the sea. In the last 15 kyr the caldera floor has suffered hundreds of meters of ground deformation alternating uplift and subsidence episodes in response to the activity of the volcanic system. The evidence of significant uplifts is witnessed...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The 4.5 ka trachytic Plinian eruption of Agnano-Monte Spina is the largest magnitude event of the past 5 ka at Campi Flegrei caldera. The complete eruptive sequence consists of six members, three of which, named A, B and D, are characterized by the association of fallout and pyroclastic density current (PDC) deposits well preserved at proximal loca...

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. Th...

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. Th...

Ground deformations are among the main volcanic phenomena occurring within the caldera system and presently recorded at different volcanoes worldwide including the Campi Flegrei active caldera (southern Italy). A new stratigraphic, sedimentological and paleontological survey carried out in the central sector of the Campi Flegrei caldera both along...

We report, for the first time, evidence of seismically induced soft-sediment deformations in the central area of the active Campi Flegrei caldera (southern Italy). We analyzed the marine-transitional and continental sequences located along the coastal La Starza cliffs and several stratigraphic logs exposed during the excavation of a 1 km long tunne...

The Baia–Fondi di Baia was a multi-stage, small-scale eruption which occurred in the western part of the Campi Flegrei caldera at 9525–9696 BP, marking the onset of Epoch 2 of post-Neapolitan Yellow Tuff volcanism. The eruption was characterized by a complex series of events related to two distinct eruptive episodes (Baia and Fondi di Baia) separat...

We report, for the first time in an active volcanic area, the field evidence of seismically- induced deformations. Structures such as sand dykes, sand volcanoes and slumps, are hosted in a marine-transitional and continental successions in the central area of the Campi Flegrei (CF) caldera (southern Italy). A detailed structural survey in an area b...

We present in this paper the results of a geophysical and geochemical survey of self potential, diffuse soil CO2 flux, soil temperature and gas permeability carried out in the Fondi di Baia craters on the western sector of Campi Flegrei caldera, one of the most hazardous active volcano in Italy, aiming at highlighting the small scale volcano-tecton...

The Campi Flegrei caldera (Italy) is an active volcanic system characterized by significant long- and short-term ground deformation phenomena ranging the maxima values in the central sector of the caldera, where La Starza marine terrace is located. A detailed study of the La Starza provided crucial clues for understanding the resurgence of the cent...

Volatile elements play an important role in many aspects of the physicochemical architecture of sub-volcanic plumbing systems, from the liquid line of descent to the dynamics of magma storage and eruption. However, it remains difficult to constrain the behaviour of magmatic volatiles on short timescales before eruption using established petrologic...

We present the results of a meso-scale systematic structural analysis of fractures, faults and dykes exposed at the Somma-Vesuvius volcano (southern Italy). Observed fractures include: (i) radial and tangential (with respect the caldera axis), sub-metric to metric joints associated with the edifice load and volcano-tectonic activity (i.e. inflation...

Volatile elements play an important role in many aspects of the physicochemical architecture of sub-volcanic plumbing systems, from the liquid line of descent to the dynamics of magma storage and eruption. However, it remains difficult to constrain the behaviour of magmatic volatiles on short timescales before eruption using established petrologic...

We present the results of a statistical study on tephra dispersal in the case of a reactivation of the Campi Flegrei volcano. To represent the spectrum of possible eruptive sizes, four classes of eruptions were considered. Excluding the lava emission, three classes are explosive (Small, Medium, and Large) and can produce a significant quantity of v...

The drilling of the Mediterranean Sea near Pozzuoli and Napoli Bay is the topic of this research. The aim of this work is to evaluate the thickness of the Campanian Ignimbrite (CI) eruption at sea, in order to complete an isopach map developed for the PDC of CI and fasten data from drilling with seismic lines that already exist. The isopach map is...

The Solfatara area and its fumaroles are the main surface expression of the vigorous hydrothermal activity within the active Campi Flegrei caldera system. At depth, a range of volcanic and structural processes dictate the actual state of the hydrothermal system below the crater. The presence of a large variety of volcanic products at shallow depth...

The Campanian Ignimbrite (CI) eruption (39 ka) occurred at Campi Flegrei, Italy, and has been the most powerful eruption in the Mediterranean area since 200 ka. This study is focused on the revision and update of the distribution and thickness data of the CI, as well as on giving information on the topological aspect ratio of ignimbrite in order to...

The Baia–Fondi di Baia eruption is one of the sporadic events that have occurred in the western sector of the Campi Flegrei caldera. It dates back to 9525–9696 bp and opened Epoch 2 of the caldera activity after a 1000-year-long period of quiescence. Although relatively small in terms of erupted volume with respect to most of the events of the past...

This study presents a new method for producing long-term hazard maps for pyroclastic density currents (PDC) originating at Campi Flegrei caldera. Such method is based on a doubly stochastic approach and is able to combine the uncertainty assessments on the spatial location of the volcanic vent, the size of the flow and the expected time of such an...

The field trip is devoted to the observation and discussion of the volcanological, mineralogical, and geochemical characteristics of the most famous/infamous leucite-bearing and -free ultrapotassic rocks and their associated shoshonites and calc-alkaline terms, generated by recycling of sediments within the upper mantle via subduction. Indeed, Cent...

In this study, we combine reconstructions of volcanological data sets and inputs from a structured expert judgment to produce a first long-term probability map for vent opening location for the next Plinian or sub-Plinian eruption of Somma-Vesuvio. In the past, the volcano has exhibited significant spatial variability in vent location; this can exe...

The Late Pleistocene Campanian Ignimbrite (CI) super-eruption (Southern Italy) is the largest known volcanic event in the Mediterranean area. The CI tephra is widely dispersed through western Eurasia and occurs in close stratigraphic association with significant palaeoclimatic and Palaeolithic cultural events. Here we present new high-precision 14C...