Reconstruction of the eruptive history Campi Flegrei caldera by means of the thermomechanical model
1Mikhail Sorokin, 2Oleg Melnik, 3Guido Giordano, 4Luca Caricchi
Affiliations: 1Faculty of Mechanics and Mathematics, Moscow State University, Russia; 2Earth Science department, University of Oxford, UK; 3Department of Science, Roma Tre University, Rome, Italy; 4Department of Earth Sciences, University of Geneva, Switzerland
Presentation type: Poster
Presentation time: Friday 16:30 - 18:00, Room Poster Hall
Poster Board Number: 212
Programme No: 3.10.13
Abstract
We use the measured sequence of individual eruptive unit volumes Vi and their dates ti at the CF caldera as the input dataset for calibrating a thermomechanical model that describes the formation and temporal evolution of a magma chamber through the incremental injection of hot basaltic dikes into cold crustal rocks (at 8-12 km depth). The model accounts for heat transfer between the magma and host rocks, solidification/melting diagrams, the displacement of the medium using an analytical solution for an elliptical crack in a homogeneous medium, and eruptions. We assume that an eruption occurs when the volume of interconnected magma with a crystallinity below a given threshold exceeds Vi. After the eruption, the system shrinks, and new magma begins to accumulate. We calibrate the parameters of the model to match the ti-Vi sequence by varying the magma supply rate, the time of magmatism initiation, and the geometry of the injection zone. Good agreement with the measured data was obtained for a supply rate of 5.4 km³/1,000 years. At this rate of magma injection, we estimate that today more than 43 km3 of eruptible magma are present within the volcanic plumbing system from a total of about 650 km3 of injected magma since 120 ka. Based on the distribution of rock density and melt fraction, we calculated synthetic seismic tomography (Vp and Vs distributions) of the CF caldera and compared it with present-day data.