The dynamics of the Campi Flegrei caldera magma chamber.

The Campi Flegrei volcanic system is certainly a remarkable case study for what concerns magma chamber dynamics. In fact, its magmatic and volcanic history appears to have been largely driven by chamber processes like fractional crystallization, magma mixing, and volatile degassing. These processes have been intensely investigated with a variety of approaches that are described in many chapters of this book, and more specifically, in Chapters 2 to 5. Here we employ physico-mathematical modelling and numerical simulations in order to study the dynamics of magma convection and mixing in a vertically extended, geometrically complex, compositionally heterogeneous magmatic system representing a schematic simplification of an overall picture emerging from previous studies at Campi Flegrei. Although clearly a simplification, a number of first order characteristics of possible real magmatic systems at Campi Flegrei are accounted for, including the more chemically evolved, partially degassed nature of magmas emplaced at shallow depths, and the likely occurrence of multiple reservoirs with different depth, size and shape which can be connected at certain stages during system evolution, allowing deeper, CO2-rich magmas to rise and rejuvenate the shallow magmas.

Japanese volcanoes visualized with muography

High-energy muons that are generated via the reaction between primary cosmic rays and the Earth's atmosphere can be used to map out the density distribution in shallow parts of a volcano's interior. This new subterranean imaging technique called muography has been applied to three different kinds of volcano dynamics in Japan: lava dome formation, vulcanian explosions and magma convection. Taking all of the observational data together, it appears that muography can serve as a new and alternative volcano observation technique, providing a fresh approach to understanding eruption mechanism. This review describes observational studies in which muography has been used to explore the volcano's interior. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.