Campi Flegrei, located in the metropolitan area of Naples, is an archetypal example of a volcanic system capable of producing catastrophic events. Indeed, there is increasing recognition among scientists focusing on Campi Flegrei that the system is reawakening, as evidenced by several types of observations since the 1970s.
The novelty of this proposal lies on the refinement of the close relationship between magma degassing and the magmatic gas reservoir feeding the hydrothermal system at Campi Flegrei. The magmatic fluids are released into the hydrothermal system during episodes of intense degassing, causing its pressurization. The slope of a P-T-H2O array during magma ascent, as determined from crystal-melt cation exchanges, can be directly related to magma cooling rate, which is in turn a function of magma ascent via the effect of pressure on volatile exsolution and degassing. Thus, magma ascent velocities at Campi Flegrei, can be determined from decompression and cooling rate experiments, elucidating the relationships between the initial ascent velocity of magmas and the depths of magma dehydration. The dynamics of gas liberation during the activity of the hydrothermal system will be also investigated and modeled experimentally. The experiments will use custom-designed shock-tube and water tank setups to reproduce scaled-down pressurized gas liberation in two phase flow systems. High-speed imaging and acoustic sensors will be used to parameterize the key dynamics of the gas liberation process. These data will provide a crucial link between the nature and type of the activity that currently occurs, or is expected to occur, at the surface and the dynamics of motion and pressurization of the gas at depth. The output of the experiments will also provide an interpretative key for monitoring the signals from current and future activity.
Hazard evaluation for explosive volcanoes in densely populated areas is a major goal for volcanology. Despite significant advances in the last decades in hazards assessment, volcano monitoring, and eruption forecasting, a predictive capability for more voluminous and explosive eruptions is far from being fully achieved. In the last decades, Campi Flegrei has been one of the world's most active caldera. The combination of dense urbanization and very active short-term deformation makes the volcanic risk in the area very high, evidencing the urgency to design and develop plans focused on volcanic hazard and risk assessment at Campi Flegrei caldera. The structure of the magmatic system consists of a partially molten region at 8 km depth, most likely representing a huge magmatic sill-like reservoir (Judenherc and Zollo 2004; Zollo et al. 2008). The temperature and H2O content of these silicic magmas range, respectively, from ~ 875 to nearly 1000 °C (Masotta et al. 2013) and from 3.5 to 6.0 wt.% (Mollo et al., 2015), with most of their differentiation controlled by fractionation of clinopyroxene followed by alkali feldspar (Mollo et al. 2016). The novelty of this proposal lies on the refinement of the close relationship between magma degassing and the magmatic gas reservoir feeding the hydrothermal system roughly located at a depth of 3.4 km (Zollo et al. 2008). The magmatic fluids would be released from this zone into the hydrothermal system during episodes of intense degassing, causing its pressurization and, in turn, producing pulses of uplift associated with shallow seismic activity (Todesco et al. 2004; Chiodini et al. 2012; Chiodini et al. 2015). The central part of the hydrothermal system is a gas plume where the mixture of magmatic and meteoric fluids moves relatively rapidly from the mixing zone to the Solfatara fumaroles and disseminated degassing structures (Caliro et al. 2007). Overall, the total amount of emitted CO2 increased in recent time and, now, it is greater than 2,000-3,000 ton/day, which is typical of the most dangerous and erupting volcanoes in the world (Cardellini et al. 2017). The experimental and modeling data from this proposal will help to understand the origin of the large amount of steam involved in the process that is currently heating the hydrothermal system through condensation. This heating process may be one of the main causes of the current deformation phase and renewed seismic activity of Campi Flegrei caldera (Chiodini et al. 2015; Chiodini et al. 2017b). The input of magmatic steam into geothermal systems is potentially a very efficient way both for heating and for deforming the rocks (Del Gaudio et al. 2010; D'Auria et al. 2015). During ascent and decompression, magmas approaching the critical degassing pressure abruptly increase their H2O release efficiency, and as such enhance their ability to convey heat to the overlying hydrothermal system (Chiodini et al. 2016).