The thermal regime of the Campi Flegrei magmatic system reconstructed through 3D numerical simulations

• Published in: Journal of volcanology and geothermal research Vol. 328; pp. 210 - 221
• Main Authors: Di Renzo, Valeria, Wohletz, Kenneth, Civetta, Lucia, Moretti, Roberto, Orsi, Giovanni, Gasparini, Paolo
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 15-12-2016
• Subjects: 3D conductive/convective model; Campi Flegrei caldera; Eruptive history; GEOSCIENCES; Hydrothermal convection; Magmatic system; Hydrothermal convection; 3D conductive/convective model
• ISSN: 0377-0273; 1872-6097
• DOI: 10.1016/j.jvolgeores.2016.11.004

We illustrate a quantitative conductive/convective thermal model incorporating a wide range of geophysical, petrological, geological, geochemical and isotopical observations that constrain the thermal evolution and present state of the Campi Flegrei caldera (CFc) magmatic system. The proposed model has been computed on the basis of the current knowledge of: (1) the volcanic and magmatic history of the volcano over the last 44ka, (2) its underlying crustal structure, and (3) the physical properties of the erupted magmas. 3D numerical simulations of heat conduction and convection within heterogeneous rock/magma materials with evolving heat sources and boundary conditions that simulate magma rise from a deep (≥8km depth) to shallow (2–6km) reservoirs, magma chamber formation, magma extrusion, caldera collapse, and intra-caldera hydrothermal convection, have been carried out. The evolution of the CFc magmatic system through time has been simulated through different steps related to its changes in terms of depth, location and size of magma reservoirs and their replenishment. The thermal modeling results show that both heat conduction and convection have played an important role in the CFc thermal evolution, although with different timing. The simulated present heat distribution is in agreement with the measured geothermal profiles (Agip, 1987), reproduces the thermal gradient peaks at the CFc margins in correspondence to the anomalies in surface gradients (Corrado et al., 1998), and suggests temperatures of 700°C at depth of 4km in the central portion of the caldera, in agreement with the estimated temperature for the brittle-ductile transition (Hill, 1992).
•Thermal modeling based on energy conservation is opportune for volcanic areas.•A 3D conductive/convective model of the CF magmatic system has been proposed.•Thermal state of CF plumbing system is important to interpret its ongoing dynamics.•Shallow transient intrusions and associate convective heat transfer fine tune thermal profiles.